Energy Management System For Future Households

Keywords:

Smart Grid – According to the European Commission a Smart Grid is an electricity network that can cost-efficiently integrate the behavior and actions of all users connected to it – generators, consumers and those that do both – in order to ensure economically efficient, sustainable power system with low losses and high levels of quality and security of supply and safety [].

Smart applications – refers to a variety of energy-related software applications which may provide utility bill tracking, real-time metering, building HVAC and lighting control systems, building simulation and modeling, carbon and sustainability reporting, IT equipment management, demand response, and/or energy audits [].

Smart Metering – A smart meter is usually an electronic device that records consumption of electric energy in intervals of an hour or less and communicates that information at least daily back to the utility for monitoring and billing purposes. Smart meters enable two-way communication between the meter and the central system [].

Energy Management – is the proactive, organized and systematic coordination of procurement, conversion, distribution and use of energy to meet the requirements. The objectives are to conserve resources, protect the environment, save costs, while users continue to have permanent access to the energy they need [], [].

Home Automation – is the extension of building automation and includes centralized control over lighting, heating, ventilation and air-conditioning, security and appliances. It can also provide healthcare related services and assistance of living [].

Table of Contents

TOC \o 1-3

Introduction PAGEREF _Toc \h 1

Problem Statement PAGEREF _Toc1 \h 3

Smart Homes PAGEREF _Toc2 \h 1

Domestic Appliances PAGEREF _Toc3 \h 2

Variable devices PAGEREF _Toc4 \h 8

Variable, but strongly user dependent devices PAGEREF _Toc5 \h 15

Not variable devices PAGEREF _Toc6 \h 18

Actual state of the domestic appliances technology PAGEREF _Toc7 \h 23

Summary of domestic appliances PAGEREF _Toc8 \h 27

Energy Sources PAGEREF _Toc9 \h 29

Photovoltaic PAGEREF _Toc10 \h 30

Combined heat and Power (CHP) PAGEREF _Toc11 \h 34

Smart Home Applications PAGEREF _Toc12 \h 37

Smart Metering PAGEREF _Toc13 \h 46

Storage Systems PAGEREF _Toc14 \h 47

Summary PAGEREF _Toc15 \h 53

Energy Management System PAGEREF _Toc16 \h 55

Algorithm PAGEREF _Toc17 \h 58

General presentation PAGEREF _Toc18 \h 58

Basic Structure PAGEREF _Toc19 \h 60

Structure of the Algorithm PAGEREF _Toc20 \h 61

Main function PAGEREF _Toc21 \h 61

Energy Management PAGEREF _Toc22 \h 67

Costs of Energy PAGEREF _Toc23 \h 70

Summary of the developed energy management system PAGEREF _Toc24 \h 74

Market Analysis of the home automation industry PAGEREF _Toc25 \h 75

Home automation and market development PAGEREF _Toc26 \h 75

Market potential PAGEREF _Toc27 \h 77

Home automation and renewable energy PAGEREF _Toc28 \h 80

Potential clients PAGEREF _Toc29 \h 81

Competitors PAGEREF _Toc30 \h 83

Summary of analysis PAGEREF _Toc31 \h 86

Summary PAGEREF _Toc32 \h 87

List of Abbreviations PAGEREF _Toc33 \h 89

List of Variables PAGEREF _Toc34 \h 90

List of Figures PAGEREF _Toc35 \h 92

List of Tables PAGEREF _Toc36 \h 94

List of Equations PAGEREF _Toc37 \h 95

List of References PAGEREF _Toc38 \h 96

Introduction

Climate change and growing shortage of resources are great challenges of the today’s world. The European Union imports 50 % of its energy consumption and it is expected to reach 70% by 2030 [].

Much progress in energy economics has been made through several conferences, workshops and forums in order to raise public awareness and help the advancement of technology in this field.

Exhaustion of low-cost fossil fuels will have significant consequences for energy sources as well as for the manufacture of plastics and many other things. New sources of fossil fuels keep being discovered, although the rate of discovery is slowing, while the difficulty of extraction simultaneously increases.

More serious are concerns about the emissions that result from fossil fuel burning. Fossil fuels constitute a significant repository of carbon buried deep underground, burning them results in the conversion of this carbon to carbon dioxide, which is then released into the atmosphere. The estimated CO2 emission from the world's electrical power industry is 10 billion tones yearly. This results in an increase in the Earth's levels of atmospheric carbon dioxide, which enhances the greenhouse effect and contributes to global warming. The linkage between increased carbon dioxide and global warming is well accepted, though fossil-fuel producers vigorously contest these findings.

The supply of energy can be disrupted by several factors, including imposition of higher energy prices due to political or economic disputes, wars or physical damage of the energy infrastructure [].

All these reasons lead to the urge in finding more environmentally friendly and sustainable energy sources. It also underlines the fact that end-users need to be more aware of their energy consumption.

The notion of sustainable energetic development has at its base the concept, that the satisfaction of the increasing energy demand should be realized, not by increasing the supply, but by reducing consumption and increasing renewable energy sources. Reduction of consumption and carbon emissions should be done by implementing new technologies and changing lifestyle and user behavior.

In order to achieve these goals, the strategic goals of energy policies are:

Increasing efficiency in energy consumption

Developing a balanced portfolio of domestic energy resources

Environmental protection

Investments in advanced technology

As energy becomes more and more expensive, the user behavior is steadily changing in order to use less of it. Also, fossil fuels being implicated in climate change, there is a growing concern to both reduce consumption and to exchange less carbon-intensive sources of energy.

This motivates not just the individual behavior, but also generates national and international legislation affecting the whole population.

There is an interest in technology that intends to both reduce energy waste and deliver alternative resources of energy in and to the home: there is a continuous development in the field of photovoltaics, battery chemistry, more efficient boilers, heat pumps, heat storage techniques and information technology is being introduced into the home with the aim to manage the energy consumption more economically [].

Solar photovoltaic power offers a viable alternative to fossils fuels for its cleanliness and supply, although at a high production cost. Future technology improvements are expected to bring this cost down to a more competitive range.

Market transformation describes both a policy objective, the overall goal to increase the energy efficient products and services and to promote the value of self-sustaining presence of energy efficient technologies in the marketplace [].

The European Union, in order to lower energy consumption, has been leaning on power producers and consumers to tighten up their acts. In 2009, it recommended that member states investigate the option of mandatory installation of smart meters.

Energy companies have incentives to promote smart devices as this can enable them to launch demand response and energy management programs, which can be efficient tools for energy conservation and can help energy companies to comply with forthcoming energy reduction mandates. Furthermore, a general reduction in peak load reduces the need for investments in reserve power generation capacity [].

The above mentioned facts induce the need to further investigate the current and future energy management strategies. Therefore, the main focus of the thesis is on researching for possibilities to change the user behavior and reduce the electrical energy consumption.

Problem Statement

Energy management means using energy in a judicious and efficient way, in order to maximize incomes (minimizing costs). It is a combination between engineering performance and financial management and it consists of establishing an optimal way in implementing new technological methods within economical limits.

As benefits we can point out:

Improves environment quality

Assures important amounts of money and energy savings

Decreases dependency on other energy suppliers

Assures national and individual development [3]

The use of electricity became largely unconsidered by most of the population, who simply switched on the lights or turned up the thermostat, whenever got dark or cold. As a result domestic energy technology has an important role when it comes to information technology especially in the interest of smart homes.

Money saving is a relatively new area for the smart home, but it is increasing and gaining interest, through rapidly rising costs and governments initiatives to implement smart grids. Home owners have an increasing number of home applications that provide control over their appliances.

In order to save energy in a more advanced method, the house should be investigated by a professional energy auditor, who with special tools analyzes how well are energy systems working, compares them to the utility bills and offers solutions how to become more efficient.

Beyond heating and cooking, other domestic appliances need electricity, to power the electric motors in fridges, washing machines and other white goods or to energize the electronics in that many audio-visual products.

A simple way to save money and reduce carbon emissions is to consume less energy, goal which is targeted by most of the monitoring technologies. Every method of generating electricity has a different economic and environmental footprint, and reducing these costs means considering how much, how rapidly and when is the energy consumed.

Smart meters provide two-way communication between the user and utility, which can help maintaining a more reliable electrical service. These meters combined with energy management systems can help the home owner in finding ways to save energy.

Efforts have been taken to offer the possibility of “load-shedding” in the domestic area, where the consumer may enter into a standing contract with the utility that would allow domestic load to be shed automatically on demand. Appliance manufacturers are considering how to build such capabilities into their devices, but the big challenge is, how the user might express their preferences about when and under what circumstances such load-shedding is considered acceptable. Time based rates are also very attractive to owners of plug-in hybrids and electric vehicles.

When it comes to renewable energy sources there is the challenge of taking advantage of the unexpected availability of energy, when the aim is not shift, but to bring forward the consumption or to store it in batteries [].

The main intention of this document is the better understanding of the actual state and future possibilities of the smart home environment, the human intention, the technicalities of this domain, device communication standards and configurations.

For this, existing systems and smart home applications have been investigated. Analysis of currently available devices and their load profiles, offers the ability to comprehend the status of the smart home market and user behavior.

Energy saving and cost reductions are essential for today’s world. Since every consumer has different needs, working schedule and budget, a general method is not effective enough. By knowing a typical day of the user more specific solutions can be set in motion. This way, not just the results are more remarkable, but it does not require uncomfortable behavior changes from the home owner.

Based on the aforementioned statements, this document investigaain intention of this document is the better understanding of the actual state and future possibilities of the smart home environment, the human intention, the technicalities of this domain, device communication standards and configurations.

For this, existing systems and smart home applications have been investigated. Analysis of currently available devices and their load profiles, offers the ability to comprehend the status of the smart home market and user behavior.

Energy saving and cost reductions are essential for today’s world. Since every consumer has different needs, working schedule and budget, a general method is not effective enough. By knowing a typical day of the user more specific solutions can be set in motion. This way, not just the results are more remarkable, but it does not require uncomfortable behavior changes from the home owner.

Based on the aforementioned statements, this document investigates every aspect of the field, in order to become familiar with this topic and to provide available and future solutions to the rising energy issues.

For this, an own algorithm has been developed, which in the first step is used to describe the load profiles of every device in a household and by this, offers precise information about the user behavior and time of use of each appliance.

This investigation allows creating a further management system. By knowing the time intervals when specific devices are usually working, energy saving methods can be introduced. By analyzing these devices, will offer the possibility to know, which devices can be shifted to another time interval, which are those that are too strongly user dependent and which are those that depend on external factors, such as weather conditions.

Besides the technical approach an economical research has been done, which includes current and future tendencies of the market and offers a more clear details about the perception of home automation and smart home technology.

In the following chapters are explained the generalities of smart homes, their application areas and technologies. Based on the overview, the developed algorithm is then presented, which has purpose to create a method to reduce the energy consumption of a house and to make it independent from the grid with the help of batteries and a photovoltaic system.

In the fifth chapter a market research for home automation is presented, which embraces the markets history, future tendencies, the macro environment of this field, potential clients and main competitors.

In the final chapter a summary of the work, conclusions and an outlook about future challenges are shown.

Smart Homes

In this chapter the investigation of smart homes will be presented.

After getting a general knowledge about the current meaning of the term, in further subchapters the components of the along coming system are described. The elements, such as appliances, sources, storages and control system will be introduced by their properties and current status of their technology.

A smart home is a residence equipped with advanced automatic systems (also called home automation systems), which cover areas such as: security (alarms, remote information and intervention), energy efficiency (automatic control and regulation over utilities) and comfort (interconnection between devices, lights, temperature).

In the smart home of the future connectivity will be embedded in virtually all household devices. Mobile connectivity will be a crucial ingredient in bringing together the different parts of the smart home puzzle.

The smart home environment is characterized by three main roles.

The first one is the user – typically the inhabitant and the family members, also guests should be taken into consideration.

The second role is devices – these allow the concrete realization of smart homes and are the interface for the user.

The third characteristic is services – they are the enabler for intelligent behavior in smart home environment [6].

The popularity of home automation is constantly growing, due to the fact that the affordability and simplicity is rising, through smartphone and tablet connectivity.

The system integrates every electrical device and combines their controls and key functions by using building automation control, technical building management and control directly upon domestic appliances.

Smart meters provide a bidirectional communication between the user and the utility, and can be used with web based tools that can be installed on devices. Smart meters display energy use, allows adjusting remotely the heating, ventilation and lighting, turning on and off appliances [].

Home automation technologies are viewed as integral additions to the Smart grid. The ability to control lighting, appliances, HVAC as well as Smart Grid applications (load shedding, demand response, real-time power usage and price reporting) will become vital as Smart Grid initiatives are rolled out. The data from smart grids is combined with home automation systems to use resources at either their lowest prices or highest availability, taking advantage, for instance, of high solar panel output in the middle of the day to automatically run washing machines.

One can distinguish 5 levels of home automation, but when speaking about the vision of Smart Homes, we only speak of real home automation from the third level onwards.

Homes which contain intelligent objects – homes contain single, stand-alone applications and objects which function in an intelligent manner.

Homes which contain intelligent, communicating objects – homes contain appliances and objects which function intelligently in their own right and which also exchange information between one another to increase functionality.

Connected homes – homes have internal and external networks, allowing interactive and remote control of systems, as well as access to services and information, both within and beyond the home.

Learning homes – patterns of activity in the homes are recorded and the accumulated data are used to anticipate users’ needs and to control the technology accordingly.

Attentive homes – the activity and location of people and objects within the homes are constantly registered, and this information is used to control technology in anticipation of the occupants’ needs [6].

Domestic Appliances

Domestic appliances are the most important elements of smart homes, since their functioning is strongly related to the energy consumption of the household. Most commonly the devices that are found in the houses are highly user dependent, consequently they don’t have an intelligent behavior. In order to successfully develop these devices, the analysis of their load profile and their current technology is needed. In the following chapter, explanations of the current settings and on further possibilities of advancements are presented.

Some manufacturers are now offering "smart" appliances – appliances that can be connected to smart electric meters or home energy management systems to help you shift your electricity use to off-peak hours. Smart appliances don't just turn off during times of peak electricity demand – instead, they use subtle ways to shift energy use. For example, the air conditioner may run slightly less often. Or the refrigerator might delay it's defrost cycle until the middle of the night, when the charges are lower for electricity.

White goods comprise major household appliances and may include: air conditioner, dishwasher, clothes dryer, drying cabinet, freezer, refrigerator, kitchen stove, water heater, washing machine, trash compactor, microwave ovens and induction cookers [].

In Figure 2.1 current home automation devices are presented and their control by different smart home applications.

Figure 2.1 Home automation devices [66]

In Table 2.1 are presented the typical appliances that can be found in a general household and their consumption in order to offer a general idea, how much power does the household items in our homes use.

Table 2.1: List of appliances and their consumption []

The numbers in the table represent the maximum power consumption. This also means that, during a cycle, the demand can differ, from one time sequence to another. For example, as it can be seen in Figure 2.2, in the case of a washing machine, more energy is needed to heat up the water than for the rising and spinning.

Figure 2.2: Load profile of a washing machine

The blue line represents the apparent power whereas the red line represents the active power, while the average consumption is presented by the green line. Households just have to pay for energy generated by the active power.

The consumed energy of a household is given in kWh and it is given by the integral of the used power over the time.

(2.1)

The annual consumption is then given by the sum of all energy consumptions generated of all devices in the household over one year.

After determining the energy consumption of the house, further categorization and investigation of appliances are possible. In detail classifications are strongly needed in developing individual user profiles and in providing personalized solutions.

One method of device classification can be observed in Table 2.2, which contains the grouping of the appliances found in the household, by their flexibility.

This means, that some devices are variable, so they can be independently used from the time of day. Their functioning can be easily shifted to later time intervals, when the energy prices are lower or there is available renewable energy.

Another category contains the devices that strongly depend on the user behavior and comfort. By changing the way of thinking of the user, these appliances can become flexible as well.

The last category consists of devices that are dependent of external factors, such as weather condition, working schedule of user. These devices can become more economical by setting up storage units.

Table 2.2 Device Categories

Each category will be presented and many of the above mentioned devices will be investigated by their load profile and working principle, available and future technology. Also, for every item, energy and cost saving options will be enumerated.

The load profiles were measured with the measurement system “Energy Logger 4000 by Voltcraft” (Figure 2.2) which allows measurement for all devices connected to a socket, with the help of Mode button different data can be displayed, both apparent and active power, minimum and maximum consumption.

Figure 2.3: Energy Logger 4000 by Voltcraft

Variable devices

This category contains devices that are not influenced by external factors and are not strongly connected to the user behavior. They can automatically operate when lower tariffs are available or the photovoltaic unit in the home provides enough power, because their functioning is not time dependent.

Devices belonging to this category are very flexible, they are not influenced by the comfort of the user, so they offer a great opportunity in energy saving and load shifting. All these efforts lead to more economical solutions and to achieve these goals manufacturers are developing appliances that are able to communicate, not just with the user, but between each other as well.

Devices that are being investigated are: refrigerators and freezers, washing machines, tumbler dryers and dishwashers.

Refrigerators and freezers

Figure 2.4 represents the load profile of a refrigerator. We can see two cycles, one when the compressor is working and it draws power in order to cool down and in the other case when no cooling takes place. If the door is open, the next cooling cycle will take place for a longer time, which leads to more energy usage. Also, the compressor is a highly reactive load, because the apparent power is much higher than the active one.

The higher peaks in some cycles are given by the measurement system. It builds up the average power of one minute. If the cycle time starts directly at the beginning of a new minute of the time in the measurement unit, the average for the first minute will be higher comparatively to the case when it starts at the end of the minute.

Figure 2.4: Refrigerator load profile

Refrigerators represent 4.5% of the total household energy consumption, thanks to recent improvements in insulation and compressors, today's refrigerators use much less energy than older models. The most common refrigerators on the market are the compact ones, which include a freezer section as well. In the European Union, for illustrating energy efficiency, seven categories of energy labels are used, starting from D (the least efficient) to A+++ (the most efficient), emphasized with colored arrows. An A++ type refrigerator uses approximately 250-350 kWh energy per year. An ENERGY STAR certified refrigerator, is at least 20% more energy efficient than the minimum federal government standard [].

Among refrigerator control options we can enumerate the adaptive control system and the real-time energy management system (EMS)

The adaptive control system is built with two controllers, one to control the compressor and condenser and the other to control the evaporator. The specific functions of the controllers enable us to adapt the number of defrost cycles and its lengths.

The real-time EMS consists of the adaptive control system upgraded by the operator enabling monitoring and control of refrigeration systems, this can provide services such as energy management, alarm handling, maintenance management and food quality management, control of the night-mode parameters [].

The information offered by the smart refrigerator can be accessed by smartphones and tablets.

It offers saving options and includes a food management system, which informs users about the food in the refrigerator, such as expiration date. The Smart Diagnosis function provides information for the call center staff to identify problems over the phone, and Smart Adapt that keeps the refrigerator software up-to-date with the latest upgrades, features and options [].

Saving tips

In order to increase the no cooling intervals, the fridge should cool down to a lower temperature. Though, the constant temperature in the refrigerator should not be too low, recommended temperatures are 3°- 4°C for the fresh food compartment and for the freezer section -15°C.

The door seals need to be airtight and the door should be opened when something is needed from the fridge.

Liquids and the food should be covered. Uncovered foods release moisture and make the compressor work harder [].

Tumbler dryers

The working principle of a traditional tumble dryers consists of drawing the cool air, which is then heated up and passed through the tumbler. This hot, humid air is then vented outside, so that the next cycle can start.

Figure 2.5 describes the load profile of this device, where the heating cycles can be easily observed, the blue line represents the apparent power, the red one the active power, whereas the average consumption is shown by the green line.

Figure 2.5: Load profile of tumble dryers

Regular tumbler dryers consume about 6.5% out of the total household consumption, On the market appeared a solar energy heated tumbler dryer, which makes direct use of the solar energy, without converting it to electricity. It has considerably low energy costs, compared to highly efficient heat-pump dryer, it is 60% more efficient than an A+++ labelled dryer. During the summer the dryer utilizes the hot water produced by a rooftop array and during the winter it can be heated using biomass or geothermal heat.

In a family of four people, the added costs of this type of machine, which are around 500 Euro, are paid off in seven years Also, the solar-heated water can be used by other domestic appliances which require water [].

Energy saving options:

Schedule the time interval when the dryer is working. Programming it to work when the tariffs are lower and no other major device is running can help to save a great amount of energy.

During the summer, clothes can be dried outdoors.

Tumble dryers with moisture sensors will automatically turn off when the clothes are dried. This helps to avoid over-drying.

Cleaning the lint trap before every load increases efficiency.

One load should consist of clothes with similar fabrics, this way all the clothes dry in the same amount of time.

The cool-down cycle allows the clothes to finish drying with the remaining heat [21].

Washing machines

As the following figure (Figure 2.2) describes, the notable power demand at the beginning of the washing cycle is due to the water heating. The length of this cycle can differ from one case to another, since it is dependent from the degree to which the washing is set. After this phase the rising cycle starts, which is then followed by the spinning of clothes.

Figure 2.2: Load profile of a washing machine

Some washing machine models are equipped with Smart Grid Technology, which allows the owner to profit from the electricity tariffs. Washing machines with second water connection allow savings up to 47% by using hot water and solar heated thermal system. Currently, in a regular household, 5% of the total consumption is used by washing machines.

Producers are carrying field studies on flexible electricity consumption, by offering intelligent washing machines, tumble dryers and dishwashers for testing. Along with the products every household has installed a smart metering device, which is connected to personal computer in order to control and manage the consumption in harmony with the electricity tariffs. Currently the tariffs must be entered manually to the gateway but the objective is to adjust it and automate the transmission of the information from the supplier to the domestic appliance [].

The smart washing machine is aimed at delivering optimal washing performance with minimal energy use, and also comes with Smart Diagnosis. Through the Smart Access function, users can monitor and control the smart washing machine on their mobile devices.

According to the European Union by 2020, 80% of the households will be equipped with smart electricity meters that allows a two-way communication between the utility provider and the individual home. For the householders, this means, the appliances will be scheduled to run when energy costs are lower [].

Energy saving options

As above mentioned, a washing machine consumes most of the energy in heating up the water. Washing clothes in cold water, using cold-water detergents whenever possible, is more efficient.

Washing and drying full loads should be done with the appropriate washing level settings.

ENERGY STAR clothes washers clean clothes using 50% less water and 37% less energy than standard washers [].

Dishwashers

The cleaning of the dishes is realized by repeatedly spraying strong jets of water on them.

As shown in Figure 2.6 the power demand peaks are due to the need for water heating to a high degree. After every cycle of water spraying, the machine drains the dirty water and pumps clean hot water again. When the program has finished, which usually take one hour, the heating element warms up the air in order to dry the dishes [].

Figure 2.6: Load profile of dishwasher

Dishwashers play an important role in Smart Grid applications, because their average energy consumption is around 5% in a regular household, their functioning is less time-critical and a finished load can be left in the machine independently from time. Drying is can be done by the AutoOpen function: This feature automatically opens the appliance door at the end of a program to release any hot, moisture-laden air from the cabinet [].

Energy Saving tips

The dish washer uses most of the energy when heating up the water.

Soaking or pre-washing is only recommended in cases of burned- or dried-on food.

Be sure the dishwasher is full (not overloaded) when running it.

Avoid using the "rinse hold" on the machine for just a few soiled dishes. It uses 3-7 gallons of hot water each use.

Air dry the dishes, if the machine doesn't have an automatic air-dry switch, turn off the control knob after the final rinse and prop the door open slightly so the dishes will dry faster [].

Variable, but strongly user dependent devices

Comparatively to the devices mentioned in the previous category, these devices need more human interaction in order to function, they are related to the user’s habits, free time and comfort. This category consists of small appliances which are in use just periodically, does not require special planning or the time interval of use is short.

In order to increase energy efficiency for this device category, steps toward changing the user behavior needs to be done. With the appropriate scheduling, loads can be shifted to lower tariff time intervals. Also sizeable amount of energy can be saved if the appliances are not left in standby mode.

In this category we can mention appliances such as hair dryer, curling iron, iron, water heater, vacuum cleaner. Their cumulated energy consumption adds up to approximately 15% of the total household energy consumptiom.

Hair dryer

A hair dryer consists of two main components: a motor driven fan and a heating element. By the combination of these two, the electrical energy is converted to convective heat.

As it is seen in the figure of the load profile (Figure 2.7), the power is needed in order to heat up the nichrome wire, through which the air passes [].

Figure 2.7: Load profile of a hair dryer

Newer hairdryers have a ceramic coating on the heating element which can heat more effectively and evenly. This can reduce the time of usage of the device, which means lower power consumption.

Also, depending on the working schedule, the load can be shifted to later times when there is available photovoltaic power or the storage units are charged.

Iron

The working principle of the electric iron is the following: when the current passes through the heating element, it is warmed up and transfers heat to the plate of the iron, which then by applying pressure will remove the wrinkles on clothes.

With the help of the thermostat, the user can set the temperature interval to which the iron should heat up.

As seen in Figure 2.8 the peaks of power demand are when the heating takes place. To prevent from overwarming, every heating cycle is followed by cooling. When reaching a certain minimum temperature another heating cycle begins [].

Figure 2.8: Load profile of iron

To become more economical from the energy consumption point of view, ironing can be done when there is available PV power or the storage unit is charged. If the working schedule does not permit the daytime usage of this device in weekdays, it can be shifted to the weekends.

Water heating

Producers have developed water heaters which include a smart module user interface that allows to adjust temperature, operating modes and gives diagnostic information. The smart module is connected to an electronic thermostat and the electrical junction box allows connecting to the home automation applications [].

Another solution is to use tankless water heaters, which heat water directly without needing a storage tank. It can be based on either a gas burner or an electric element that heats the water. Typically, these water heaters provide hot water at a rate of 7.6–15.2 liters per minute. To overcome this limit, two or more tankless water heaters can be installed, connected in parallel for simultaneous demands of hot water, or separate tankless water heaters should be installed for appliances such as a clothes washer or dishwater.

Tankless water heaters can avoid the standby heat losses associated with storage water heaters, but they use a large amount of electricity to heat up the water instantly [].

Not variable devices

The not variable devices are those that are being used independently from the cost of energy, they are usually influenced by exterior circumstances, such as weather, time of day, working schedule and user comfort as well.

Devices belonging to this category require the presence of the user. For example, there is no use in turning on the TV when nobody is home, set a high room temperature in chambers which are just occasionally occupied.

This category includes a large variety of appliances such as coffee machines, heating and air conditioning, home office and lighting.

Appliances such as coffee machine rely on the comfort of the user and on the preference to drink it freshly cooked.

Heating, ventilation and air conditioning

Space heating represents around 40% and heating, from which hot water represents approximately 15% of the total energy consumption in a household. Most of the space heaters use approximately the same amount of energy 1500 watts, which is converted into heat.

As shown by the load profile of the ventilator in Figure 2.9, after a long warm up phase, the unit alternatively turns off and on at a certain temperature. This switching takes place continuously while working but in a varying time interval.

Figure 2.9: Load profile of a hot air ventilator

Infrared units are energy efficient heaters, as they generate infrared heat that conducts through the humidity in the air and penetrates into the objects in a home. By setting the thermostat, the unit shuts down when reached the desired temperature [].

A digital programmable thermostat set for energy savings during the heating season can save energy and money. Using a programmable thermostat, the owner can adjust the times when to turn on the heating or air-conditioning according to a pre-set schedule. Programmable thermostats can store and repeat multiple daily settings.

Programmable thermostats are generally not recommended for heat pumps, due to the fact that, when a heat pump is in its heating mode, setting back its thermostat can cause the unit to operate inefficiently, which generates costs. However, some companies have begun selling specially designed programmable thermostats for heat pumps, which make setting back the thermostat cost-effective. These thermostats typically use special algorithms to minimize the use of backup electric resistance heat systems [].

Another cost effective solution is to control the heat individually in every location of the house, taking into consideration which room should be warm during the evening and morning, which rooms are not in use just in special occasions.

There is a self-learning thermostat developed, which within a training period determines the needed time to heat up the room to the desired temperature and switches itself on and off, it makes up a schedule, which can be adjusted and controlled from everywhere via smartphones. Besides temperature, the thermostat also has sensors in order to detect humidity, activity and light sensors [].

The efficient control of air-conditioning system is also realized by programmable thermostats.

Also, there are several devices which control HVAC systems. They divide the house in several heating zones, the temperature can be set independently, air humidity and freshness is taken into consideration. If the windows are open the system stops, which also lead to savings. These devices have integrated thermostats which show the current temperature and allow the desired one to be set [].

Microwave ovens are often a much more energy efficient way of cooking items than in the oven. This is because microwave ovens use energy to directly heat your food, whereas electric ovens must also heat the air inside the oven.

Home office and entertainment

Televisions, set-top boxes, digital TV recorders, DVDs and DAB radios combined are responsible for around a fifth of a typical home's electricity bill. 

Digital television recorders: Recording shows doesn’t have to cost. In most homes, entertainment equipment accounts for about 10% of the final electricity bill.

Televisions can be the most power-hungry of all entertainment appliances, particularly the larger ones. The larger a television is the more energy it will consume, regardless of its energy rating. Choosing a smaller TV generally means choosing a more efficient TV, but this is an aspect where user comfort steps in. The power variations that can be seen in the load profile (Figure 2.10) are caused by light/dark scenes, brightness and volume settings.

Figure 2.10: TV load profile

Household computers, printers, monitors and laptops on average make up around 13% of electricity around the home. Choosing an energy-efficient computer can also have a real impact on carbon dioxide emissions and energy costs.

Laptops (Figure 2.11) have a similar load profile as televisions, but since they are smaller in size, they consume less energy.

Figure 2.11: Laptop load profile

Energy Saving tips

ENERGY STAR rated products use around half the electricity of standard equipment, but by selecting energy-efficient office equipment, can result in important energy savings.

Turning devices off when they are not in use or spending time in low-power mode saves energy and by running cooler can prolong the life of the device.

Power management settings on computers and monitors can result in savings.

In the case of laptops and computers automatic switching to sleep mode can save energy.

Laptops use less energy than desktop computers.

By unplugging appliances "phantom" loads are avoided. These loads occur in most appliances that use electricity, such as DVD players, TVs, stereos, computers, and kitchen appliances, and they occur when the device is not functioning, but it is plugged.

Using rechargeable batteries are more cost effective than disposable batteries [].

Actual state of the domestic appliances technology

The Smart Grid, with its system of controls and smart meters, will help to effectively connect all the mini-power generating systems (such as local rooftop solar panels, small hydropower, and wind turbines) to the grid, to provide data about their operation to utilities and owners, and to know what surplus energy is feeding back into the grid versus being used on site.

Miele’s Smart-Grid enabled appliances are equipped with a communication module which is able to communicate with the Internet via power lines and the Miele gateway. This gateway also provides the electricity board's rates and tariffs.

'SmartStart' allows users to define the time at which, a program must have been completed in advance. Within this time window, the program is then launched when electricity is cheapest [].

Miele was the first manufacturer in the world who offered Smart Grid ready Domestic Appliances. This means that the washing machines, dishwashers and tumble dryers with the SG logo are able to take into consideration the price of electricity [].

Miele has also released appliances with intelligent electric controls. Whenever there is a problem with an appliance – such as overheating – the owner will be contacted via the Internet to notify them. Users will also receive e-mails to remind them to clean out the tumble dryer’s fluff filter or to warn them that the Miele refrigerator door has been left open [].

Miele's SmartGrid dishwasher lineup comprises four products which are either integrated or fully integrated. These models achieve the highest energy efficiency rating of A+++ and, depending on the programme, get by with as little as 7 litres of water per cycle. Further convenience features include AutoClose, offering effortless door closure, and a salt reservoir integrated into the dishwasher door [19].

SmartGrid dishwashers also support the 'ExtraQuiet' programme which boasts sound emissions of as low as 40 dB. This makes these models the ideal candidates for installation in open-plan kitchens or in homes where the dishwasher is switched on to run overnight.

Lighting & Lightning-Control

Lighting means the use of both natural illuminations, by capturing daylight and artificial light sources like lamps and light fixtures. 

Daylighting is usually used as the main source of light during daytime in buildings. This can save energy in place of using artificial lighting, which represents a major component of energy consumption in buildings.

Lighting fixtures come in a wide variety of styles for various functions. The most important functions are as a holder for the light source, to provide directed light and to avoid visual glare. Some are very plain and functional, while some are pieces of art in themselves. Nearly any material can be used, so long as it can tolerate the excess heat and is in keeping with safety codes.

Lamps, usually called 'light bulbs', are the removable and replaceable part of a light fixture, which converts electrical energy into electromagnetic radiation.

While lamps have traditionally been rated and marketed primarily in terms of their power consumption, which is expressed in watts, development of lighting technology beyond the incandescent light bulb has eliminated the correspondence of wattage to the amount of light produced. Each technology has a different efficacy in converting electrical energy to visible light, which is measured in lumens [].

Lamp types and their characteristics are compared in Table 2.3.

Among lamp types we can enumerate:

Incandescent lamp – a filament wire heated up to a high temperature by an electric current passing through, until it glows

Fluorescent lamp – a tube coated with phosphor, containing low pressure mercury

Halogen lamp – incandescent lamps containing halogen gases, such as iodine or bromine, which increases efficacy

Neon lamp – a glass tube containing low pressure gas

Light emitting diodes (LED) – emit light by the movement of electrons in a semiconductor material

Compact fluorescent lamps – are designed to replace incandescent lamps

The main characteristics to describe lamps, are the following:

Luminous Flux – the measure of the perceived power of light

Luminous Efficacy – the measure how well a light source produces visible light

Color temperature – is the characteristic of visible light and it is the temperature of an ideal black body radiator that radiates light of comparable hue to that of the light source

Color rendering index – is the ability of a light source to reveal the colors of objects faithfully to their color in natural light

Nominal power – the power for which the system is designed to function

Since lighting represents a fair amount of a building’s energy consumption, about 10%, governments have passed measures to make lighting more energy efficient. In the European Union, starting from 2009, the banning of incandescent lights has started, manufacturers and importers can no longer sell incandescent bulbs of 100 W or above, also frosted bulbs and high-energy halogen lights are being phased out. According, to the European Commission, these measures will result in the reduction of carbon dioxide emission by 15 million tons each year and by 2020 enough energy will be saved to power 11 million households every year [].

Table 2.3 Lamp types [8]

Lighting control refers to the control of lighting in a particular location and it includes occupancy sensor, photocells, time clocks and adjustment occurs manually at each location.

Lighting control systems refer to an intelligent networked system of lighting control devices. These include relays, sensors, light control switches and signals from other control systems. The systems adjustment can be both, manually at the device or at central computer locations via software programs or interface devices.

The major advantage a control system has over a stand-alone control is the ability to control multiple light sources from a single user interface, longer lamp life, less energy consumption. Additionally wireless control systems provide reduced installation costs and flexibility over where switches and sensors may be placed.

Smart Control Technology provides centralized control, allows implementation of scheduling, occupancy control and senses daylight.

Occupancy sensors range in cost from around $30 to $130, depending on the type and manufacturer. The simple payback period from their installation ranges from 0.5 to 5 years, depending on the level of occupancy and the potential for energy savings in the building or area [] [].

Summary of domestic appliances

Based on the previous facts and presentation of different devices it can be concluded, that at the current moment, the smart device market is in a developing phase. Research has shown, that in many cases, the control has to be realized directly by the user. Also there is no communication between different products by different manufacturers are either problematic or non-existent.

To get a deeper look about the general consumption of a household, load profiles are presented below. The give an overview about the behavior of the habitants and their daily profiles.

Load profiles of the energy consumption in a house are strongly influenced by weather condition, number of residents and time of week. In the figures below two cumulated load profiles are presented. The first one represents a one person household, while in the second one, the load profile of a five person family is shown. It can be seen how much the consumption is influenced by the number of persons who live in the house

Figure 2.12: Load profile of consumption in a one-person household

Figure 2.13: Load profile of consumption in a five person family

..

Energy Sources

Recently, a strong rise in the renewable energy market can be observed, due to the growing concern to protect the environment, reduce costs and issues related to energy security, government regulations and initiatives, coal plant retirements and increasing interest in energy efficiency.

16% of the global energy consumption is assured by renewable energy sources, from which 10% is covered by biomass (mainly for heating), 3.4% hydroelectricity, and new renewable (wind, solar) cover the rest 3%.

The incentive to use only renewable energy is strongly motivated by global warming and other ecological and economical concerns. The growth of renewable energy usage shows a fast evolution, in domestic area as well as in the industrial zone [].

The most popular applications in domestic systems are the grid-connected photovoltaic (PV) and the combined heat and power (CHP) systems.

Photovoltaic

Solar systems are now, after hydro and wind power, the third most important renewable energy source in terms of globally installed capacity. Due to the advancing technology, installation costs are steadily declining, while efficiency is rinsing. These factors support PV installations in many countries.

A photovoltaic system is an arrangement of components designed to supply usable electric power for a variety of purposes, using the sun (or, less commonly, other light sources) as the power source.

Currently in Europe, solar photovoltaic power is used primarily in Germany and Spain where the governments offer financial incentives. In the U.S. Washington State also provides financial incentives. Photovoltaic power is also more common, as one might expect, in areas where sunlight is abundant.

Photovoltaics is a fast growing market: On average, installations have grown by more than 48% annually in the period from 2000 to 2012. Europe contributed 66 % of the total cumulated installations in 2012. In contrast, installations in China and Taiwan accounted for 7 % of the total cumulated installations

Photovoltaics supplied about 4.7 % of Germany’s electricity demand in 2012 Renewable sources delivered about 23 % of the electricity in 2012. According to the German Federal Network Agency, in March 2014, Germany has installed PV plants of a total of 36.2 GW nominal power. [43] Most of the installed PV systems in Germany are connected to the low voltage grid and generate electricity in close proximity to consumers [].

PV system performance has strongly improved. The typical Performance Ratio has increased from 70 % to about 85 % over the last 15 year. The record lab cell efficiency is at about 25 % for monocrystalline silicon and 17 % for Cadmium Telluride (CdTe) solar cells.

Also the Energy Payback Time for Silicon (Si) PV modules is about one year for locations in Southern Europe; thus the net clean electricity production of a solar module is 95 %.

The Energy Payback Time of PV systems is dependent on the geographical location: PV systems in Northern Europe need around 2.5 years to balance the inherent energy, while PV systems in the Southern Europe equal their energy input after 1.5 years and less [16].

Solar power is pollution-free during use, production-end waste and emissions are manageable with existing pollution control methods, also PV installations can operate up to 100 years with little maintenance or intervention [].

Grid-connected photovoltaic power systems consist of Photovoltaic panels, Maximum power point tracking (MPPT), solar inverters, power conditioning units and grid connection equipment. Unlike Stand-alone photovoltaic power systems these systems seldom have batteries. When conditions are right, the grid-connected PV system supplies the excess power, beyond consumption by the connected load, to the utility grid. It can as well contribute to the reduction of transmission and distribution costs [].

Figure 2.14: PV System on a rooftop and Inverter on the wall []

Residential grid-connected photovoltaic power systems with a capacity around or less than 10 kilowatts can meet the load of most consumers and they can feed the excess power to the grid. A smart meter will give feedback and monitor the transferred power, this is also called net metering. If the photovoltaic wattage is less than the average consumption, the consumer will be able to buy grid energy. If the photovoltaic wattage exceeds the average consumption, the produced energy will be in excess of the demand. In this case, this power can earn revenue by being sold to the grid.

Depending on their agreement with their local grid energy company, the consumer only needs to pay the cost of electricity consumed less the value of electricity generated. This will be a negative number if more electricity is generated than consumed. Additionally, in some cases, cash incentives are paid from the grid operator to the consumer.

Connection of the photovoltaic power system can be done only through an interconnection agreement between the consumer and the utility company. The agreement details the various safety standards to be followed during the connection.

In Figure 2.3, a cost comparison is shown, between implementing a 4kW PV System in Germany and the U.S.

Figure 2.15 Cost of implementing 4kW PV system []

In order to build up an intelligent household energy management system, not just the loads, but the behavior of sources has to be understood as well. Therefore, below power profiles for the photovoltaic plants are presented.

The load profile of a 5 kW PV system is presented in the figures below (Figure 2.17 and Figure 2.18), in two cases, one during winter time, while the other in the summer. As it can be seen the power production is in the middle of the day, with peaks around noon.

Since, the behavior of the PV systems are strongly dependent of the weather, the load profiles are affected. During winter times, the daylight is shorter and less powerful, so the production times are shorter and lower as well. In summer time, production starts earlier and stops later. Short peak drops can be caused by cloud drifts or short rains.

Figure 2.16: PV load profile – winter

Figure 2.17: PV load profile – summer

Combined heat and Power (CHP)

Combined heat and power (CHP) or cogeneration is the use of a heat engine or power station to simultaneously generate electricity and useful heat. The Micro – CHP is the extension of the idea of cogeneration to the family homes or small offices.

Figure 2.18 : Combined Heat and Power Diagram

CHP systems are able to increase the total energy utilization of primary energy sources, such as fuel and concentrated solar thermal energy. CHP has been steadily gaining popularity in all sectors of the energy economy, due to the increased costs of fuels, particularly oil-based fuels, and due to environmental concerns, particularly climate change.

In many cases industrial CHP systems primarily generate electricity and heat is a by-product; micro-CHP systems in homes or small commercial buildings are controlled by heat-demand, delivering electricity as the by-product. When used primarily for heat in circumstances of fluctuating electrical demand, micro-CHP systems will often generate more electricity than is instantly being demanded.

Micro-CHP systems achieve much of their savings and attractiveness to consumers, through a "generate-and-resell" or net metering model where in-home generated power exceeding the instantaneous in-home needs is sold back to the electrical utility. This system is efficient because the energy used is distributed and used instantaneously over the electrical grid. The main losses are in the transmission from the source to the consumer which will typically be less than losses incurred by storing energy locally or generating power at less than the peak efficiency of the micro-CHP system. So, from a purely technical standpoint dynamic demand management and net-metering are very efficient.

As it is shown in Table 2.4 shows, the future of combined heat and power, particularly for homes and small businesses, will continue to be affected by the price of fuel, including natural gas. As the technology advances and fuel prices continue to climb, this will make the economics more favorable for energy conservation measures, and more efficient energy use, including CHP and micro-CHP. Production costs will decline, while efficiency and operation lifetime will increase. The recent development of small scale CHP systems has provided the opportunity for in-house power backup of residential-scale photovoltaic (PV) arrays.

Table 2.4: Evolution in time of CHP technology

Combined heat and power solar (CHAPS), is a cogeneration technology used in concentrated photovoltaics that produce both electricity and heat in the same module. The heat may be employed in district heating, water heating and air conditioning, desalination or process heat.

The results of a recent study show that a PV+CHP hybrid system has the potential to radically reduce energy waste in the electrical and heating systems and also enables the share of solar PV to be expanded [],[].

The German government is offering large CHP incentives, including feed-in tariffs and bonus payments for use of micro-CHP generated electricity.  North-Rhine Westphalia launched a 250 million subsidy program for up to 50 kilowatts lasting until 2017 [].

Combined heat and power systems are presented due to the fact that besides photovoltaic systems they are the most spread decentralized energy source in the residential area. Although, the focus of this thesis relies on the photovoltaic systems and they will not be further analyzed, in the further development of the management systems they should be taken into consideration.

Smart Home Applications

Within the concept of energy management, the main focus of the thesis is on applications developed for smart homes. In order to get a deeper knowledge, in this chapter the investigation of the existing technologies, communication protocols and control systems are presented.

An Energy Management Software refers to a variety of energy-related software applications which may provide utility bill tracking, real-time metering, building HVAC and lighting control systems, building simulation and modeling, carbon and sustainability reporting, IT equipment management, demand response, and/or energy audits [].

Smart home applications can be segmented by the next characteristics:

Time saving applications – which enable existing tasks to be completed more quickly or with less human input

Environment enhancing applications – which make the homes more comfortable by controlling the heat, lights, air conditioning more intelligently.

Money saving applications – which reduce energy consumption or water usage

Entertainment or time using applications – which provide methods to make leisure ime more enjoyable [6].

Figure 2.19: Smart home application structure [20]

A Smart Home defines a residence that uses a home controller to integrate various home automation systems that allow the owners to monitor and control a wide range of applications, with improved energy efficiency, access control, security.

There are many operators and manufacturers who already launched different applications that can be managed over the internet via smartphones.

Future Smart Homes will integrate all applications and will be able to control them, even if the components are from different producers.

Among networking technologies we can mention INSTEON, X10, ZigBee, Z-Wave or C-Bus.

There are several mobile applications for both iOS and Android operating systems which operate with wireless signal: INSTEON Hub, Loxone, xComfort (developed by Eaton), Wiser Home Control (developed by Schneider Electric), ProSyst apps (manufacturer for Miele products, E-car integration, surveillance services).

Samsung also developed an application for the Smart Homes, and intends to enlarge this service through partnerships with third-party service providers in the home appliance sectors, helping foster joint commercial opportunities and grow the connected home service marketplace.

In 2013, Samsung created a Smart Home Steering Committee to align all of its product groups behind the Smart Home platform. The company also plans to team up with partner companies to offer additional applications for home energy, secure home access, healthcare and eco-home services [].

A new solution is to combine configuration and control protocol via Bluetooth communication.  It will allow consumers to control any Bluetooth Smart enabled device in the home from wherever they are, including lighting, heating, appliances and security systems. Crucially for the consumer experience, solutions based on the protocol don’t require the complex setup, pairing, or use of an access device such as a router [].

Communication protocols

Communication protocols are systems containing digital rules for data exchange between computers. In the following the most common protocols in home automation will be presented.

The concept of mesh network means there's more than one way to get the message to the destination.

INSTEON is a mesh network, in order to connect lighting switches and loads without wiring. It is designed to enable devices such as light switches, thermostats and different types of sensors to be networked together using the power line or radio frequency [].

X10 is used for communication between domotics and it uses power line wiring for control, but a wireless radio based protocol is also defined. It allows compatible products to communicate between the already existing electrical wires. The appliances and devices are receivers, and the means of controlling the system, such as remote controls or keypads, are transmitters.

In order to turn off a lamp in another room, the transmitter will issue a message in numerical code that includes the following:

An alert to the system that it's issuing a command

An identifying unit number for the device that should receive the command

A code that contains the actual command, such as "turn off" [].

ZigBee is used to create personal area networks built from low power digital radios. It is used for applications that require a small amount of data rate, long battery life and secure networking. It has added services, such as monitoring plug-in electric vehicles. This is also a mesh network [].

Z-Wave, another mesh network, is a wireless communication protocol designed to remotely control applications in residential environments, it can be easily embedded in electronic devices, such as remote controls, smoke alarms and security sensors [].

It uses a Source Routing Algorithm to determine the fastest route for messages. Because this routing can take up a lot of memory on a network, Z-Wave has developed a hierarchy between devices: Some controllers initiate messages, and some are "slaves," which means they can only carry and respond to messages [].

Some open source protocols are as well available on the market, mainly for low-cost and low-power control networks, for applications such as sensor networks, security and monitoring. These protocols can be implemented to transceivers and micro controllers from different manufacturers. (For example One-Net, OSIAN or TinyOS) [].

Applications

INSTEON Hub is an INSTEON central controller, a device that connects the owner to his home from any smartphone or tablet, anywhere in the world. It controls INSTEON light bulbs, wall switches, outlets, and thermostats at home or remotely and receive instant email or text message alerts from motion, door and window, water leak, and smoke sensors if the user is remote from the house [].

The Loxone Miniserver is the centerpiece of the Loxone home automation solution. It allows to control all the appliances in a home. Ranging from simple blind control to intelligent and cost-efficient zoned heating systems.

With a user-friendly configuration software everything can be configured and can be controlled by applications on smartphones, tablets or PC-s [].

Figure 2.20 – Loxone Home Automation Solution []

Eaton’s xComfort application does not just control the machines left turned on, the lights and heating and ventilation systems, sends notifications via mobile phones, but also offers burglary and fire protection, the possibility of installing a panic button and presence simulation [].

Prosyst is a German Company, collaborating with appliance manufacturers, such as Miele, who’s application can be used for home monitoring, home automation, energy efficiency, smart heating, smart heating and the possibility of collaboration with a smart grid [].

LG in a partnership with the free Line messaging app created a service, called HomeChat (see Figure 2.26). The application lets the user to you send texts to compatible LG appliances. It works on Android, BlackBerry, iOS, Nokia Asha, and Windows Phone devices as well as OS X and Windows computers.

This update is very useful, since a frequent complaint about LG's Smart ThinQ line products were that all the devices require different apps.

The LG devices that are able to synchronize to the HomeChat network include a washing machine, oven, refrigerator and a robotic vacuum [].

Figure 2.21: HomeChat application []

Panasonic has developed a connected home, which is connected to medical facilities, allowing owners to do their own medical checkups from home.

In the spring of 2014, outside of the Japanese city of Fujisawa, Panasonic will open the Fujisawa Sustainable Smart Town, a purpose-built, green city, containing 1,000 houses, all connected to a single smart grid, enabling the electricity supply to be lined up with demand. Every house will come equipped with photovoltaic systems, home fuel cells and sensor-controlled lighting. This means a cut of 70% in emissions compared to standard communities of the same size.

Projects of this type are the ideal but they also offer possibilities for further research, which will end up in finding altered solutions for older European cities [].

Regardless of the used technology (X10, INSTEON; Z-Wave) the term “scene control” is repeatedly present. Scenes can be used for setting your wakeup conditions in the morning, setting a theater environment to watch your favorite movie, locking up the house and turning on the security at bedtime. Each scene can be initiated with a single timed event or by pushing a single controller button.

Setting Wakeup Conditions – The controller will raise the lights to 30% brightness, sets background music to low volume fifteen minutes before getting up, it turns on the coffee pot on in the kitchen, warms up the towel warmer in the bathroom and turns on the bathroom light. At the designated wakeup time, it will raise lights to 60% brightness and turns on music or TV up to medium or high volume.

Setting a Theater Environment –Pushing the Theater Scene button on the remote control will result in dimming of the lights, the TV turned on and the speakers turned up to high volume. If someone rings the doorbell or the phone rings, the lights come back up and the movie pauses.

Going to Bed – All exterior doors are automatically locked, every light in the house is turned off, the thermostat is lowered, and the night alarm system is enabled [].

In April 2014, Honda revealed a smart home concept which utilizes an ultra-efficient design that combines solar panels and energy saving smart technology. The prototype functions like a mini power plant and energy grid. Beside the solar panels, it is equipped with an electric vehicle and a 10 kWh lithium battery pack. The Honda Energy Management System distributes the power in the most efficient way, by deciding when to pull from the battery and when to store up for later, also, it is capable of improving grid reliability, by responding to demand response signals and providing several grid services, such as supplying power to the grid [].

In addition to that, the home will function as a “living laboratory” where the researchers will evaluate new opportunities at the meeting point of housing, transportation, energy and environment. Honda’s environmental efforts extend beyond personal mobility to cars and homes. According to research, powering houses and light duty vehicles contribute to 44% of U.S. greenhouse gas emissions.

The house brings together all the latest innovations and green building technology. It contains a 9.5 kW roof mounted PV system, an electric vehicle, geothermal radiant heating and cooling, advanced lighting, passive design (the construction of the house takes into account the weather conditions of the area), sustainable materials and waste management system [].

Figure 2.22: Honda Smart House Concept []

The Sunny Home Manager is a part of SMA-s smart home product package. This application is accesible via PC and Smartphone. The user can benefit from automatic functions and evaluation charts. The radio controlled sockets are used to control the appliances, but also as repeaters, to ensure a reliable connection to the network.

SMA is the first manufacturer of an energy management solution that provides load control and allow integration of power storage systems. It refers to weather forecasts, predicts PV power generation and considers time of use electricity rates when it comes to load shifting. It can control all compatible household items via internet, on PC or smartphones. Users can follow functions, charts, different evaluations with high precision [].

Figure 2.23: SMA flexible home manager system

As shown in Figure 2.9, the system is able to shift the activation of electrical loads which increase the rate of self-consumption and reduces dependence of grid and costs of electricity.

Figure 2.24 : Load profile of a household equipped with the SMA Sunny Home Manager

Smart Metering

In order to achieve the European and national energy policy objectives, new global approach in generation, transmission, distribution, metering and consumption of electricity is necessary.

A smart meter is usually an electronic device that records consumption of electric energy in intervals of an hour or less and communicates that information at least daily back to the utility for monitoring and billing purposes. Smart meters enable two-way communication between the meter and the central system.

Smart meters have a digital display and are similar in size to regular meters. Various types and models of smart meters are available, but all of them have the same basic functionality. Using a communications network, the internal antenna present in smart meters sends electricity consumption data to the utility. An external antenna may be required in some cases for improving signals over longer distances and ensuring reliable data transmission. This antenna can be attached on or near the meter box.

Smart meters can also record the energy that is fed back into the distribution network from co-generation sources, such as wind turbines and solar panels.

Smart metering communication technology enables centralized meter reading, so meter readers don’t have to visiting individual premises for data collection. However, the meter may need to be examined occasionally for testing and maintenance [].

Smart meters have the capability to offer a vast amount of data. However, the meter is just one of the sensors and actuators in the grid, they are an important first step towards smart grids, since they bring intelligence between the grid and the final costumer. A smart meter is also capable of monitoring supply disruptions, diagnostics of electrical components, meter system status, remote configuration, power limitation, load management, both by network operator and customer, interface to home communication systems and energy management systems [1].

Storage Systems

The main challenge of the current electricity system is that electric power demand varies during the day and during the year. In many cases the load profile of the appliances used by a household are not in synchrony with the load profile of the power generated by the PV system.

A method to balance out the differences is to mount storage systems, which can store up the additional power generated by the photovoltaic system and provide energy at later times when it is needed.

In the following, a brief description of energy storing possibilities are presented.

Grid energy storage is a method to adapt energy consumption to energy production, which is done to increase efficiency, lower the costs, facilitate the use of the energy sources and ensure reliability of the delivery system by ironing out irregularities in energy output. Also, energy storage has the ability to provide backup power and stabilization services.

Storage systems reduce grid load by limiting the maximum feed in capacity, thus avoiding power loss due to throttling.

There are several types of available energy storage technologies, such as pumped hydro, compressed air energy storage, various types of batteries, flywheels, electrochemical capacitors, etc., which can be used for multiple applications: energy management, backup power, load leveling, frequency regulation, voltage support, and grid stabilization. Importantly, not every type of storage is suitable for every type of application, motivating the need for a portfolio strategy for energy storage technology [].

In households energy storage is realized by batteries. In the Table 2.5 the commercially available batteries and their characteristics are presented.

As shown in the figure below (Figure 2.17), batteries come in many shapes and sizes and they can use different chemicals, such as lead-acid, nickel-cadmium. Lithium-ion, lithium-ion polymer. Main standpoints when it comes to battery characterization are: the nominal cell voltage, energy density, specific power, self-discharge rate, cycle durability and time durability [].

Figure 2.25: Battery units []

Based on assumptions, specialists say, that for a typical household a suitable PV/Battery set-up would have a 5.3 kW solar PV system for the day and a 10.6 kWh battery capacity for the night [].

A battery is a device that contains electrochemical cells, which convert chemical energy into electrical energy. Each cell consists of a positive and a negative terminal (cathode, anode), while electrolytes allow ions to move between the terminals, which allows current to flow out of the battery to perform work [].

Currently the technology has a main focus on the lead-acid, lithium, sodium-sulfur, vanadium-redox, polysulfide-bromide and redox-flow batteries, the development is assured by the advancement of the industry [].

Table 2.5: List of commercially available battery types

By charging batteries in low demand periods and discharging it when the demand is higher the than the power generated by the PV system can help in eliminating the need to draw energy from the grid.

Another storage possibility, which shows a steadily increasing interest is the usage of E-cars as storage systems. Further on this topic will be elaborated.

E-Cars as storage systems

An electric vehicle (EV) uses one or more electric motors or traction motors for propulsion. Three main types of electric vehicles exist, those that are directly powered from an external power station, those that are powered by stored electricity originally from an external power source, and those that are powered by an on-board electrical generator, such as an internal combustion engine (hybrid electric vehicles) or a hydrogen fuel cell. 

An electric car is an automobile that is propelled by one electric motor or more, using electrical energy stored in batteries or another energy storage device. Electric motors give electric cars instant torque, creating strong and smooth acceleration [21].

Since EVs can be plugged into the electric grid when not in use, there is a potential for battery powered vehicles to even out the demand for electricity by feeding electricity into the grid from their batteries during peak use periods (such as midafternoon air conditioning use) while doing most of their charging at night, when there is unused generating capacity.

In Figure 2.8 an outlook of batteries for 2020 is described, each type of battery is presented by the following characteristics: performance, safety, life span, specific power, cost, specific energy. Challenges are, to build batteries with increased performance at minimal costs.

Figure 2.26: Batteries for Electric Cars. Opportunities and outlook for 2020 []

A method to reduce the need for new power plants is the vehicle-to-grid connection. This means that the vehicle’s battery is being drained during the day by the power company.

Furthermore, the current electricity infrastructure needs to deal with increasing shares of variable-output power sources such as PV solar panels or windmills. This could also change the speed at which the batteries are charged or discharged.

Concepts are, as shown in Figure 2.9, these exchanges and the charging will take place at stations as gas or petrol stations. These stations will need huge charging and storage potential, which would be manipulated to vary the speed of charging, power output during shortage periods to stabilize the grids [].

Figure 2.27 : Vehicle to grid concept []

Vehicle to grid is a version of battery-to-grid power applied to vehicles. There are three concepts vehicle-to-grid:

A hybrid or Fuel cell vehicle, which generates power from storable fuel, and produces power for utilities during peak periods with its generator. The vehicles produce power from fossil fuels, biofuels or hydrogen, so they serve as a distributed generation system.

A battery-powered or plug-in hybrid vehicle, which by its rechargeable battery capacity is able provide power to the grid in period of peak load demand, and then they can be charged during off-peak periods, when the energy is cheaper. Here the vehicles serve as a distributed battery storage system to buffer power.

In the case of solar vehicles, they use their excess charging capacity to provide power to the electric grid when the battery is charged. Basically, the vehicle will become a small renewable energy power station. Such systems have been in use since the 1990s and are routinely used in the case of large vehicles, especially solar-powered boats.

When it comes to smart grid technology, the vehicle to grid system will be able to monitor the status of the grid and to determine if additional power is required by the grid, from sources that can respond rapidly, or if the power demand can absorb transitional power supply. A system of this kind, has the potential to reduce or eliminate the fluctuation of the grid, which can be frequent if renewable energy sources are introduced to the grid. The owners of electric vehicle will benefit from supporting a more stable power grid, which can mean reduced utility costs for the vehicle owner [],[].

Nissan developed an electric vehicle that is capable to supply a household with energy stored in the car’s battery (Figure 2.23).

A power control system (PCS) needs to be installed, which connects the lithium-ion battery to the household’s distribution board while plugged in. Through the system the energy delivery can work in both ways.

The stored energy has to be converted and this is realized by the PCS as well [].

Figure 2.28: Vehicle to homes []

PV Home Storage Systems

Some batteries are suitable for temporary storing solar energy. Integrating battery systems into decentralized PV installation to increase the consumption of generated solar power have become attractive for end customers, due to the fact that they can provide energy when the demand is higher than the production.

Implementing such batteries can help in balancing the consumption to the production. Among the benefits we can enumerate the followings: less electricity usage, boosted self-consumption, which means more independence, system’s compatibility with the smart grid.

A suitable lithium-ion battery would have:

Battery size: 5.33 kWh

Number of cells/modules: 36/3

System capacity: 120 Ah

Rated voltage: 44.4 V

Continuous current/ peak current: 100A/200A

Weight: 75 kg

L x W x H: 790x250x575 mm

Air cooling system with optimized control

Cycle numbers: >2000

Modular setup

Optimized thermal design

Highly efficient with a wide range of applications

Simple to mount and maintain

The hardware and software for such batteries are developed to meet the requirements of the user and application. Among key features we can mention its capability to me to measure individual cell voltage and temperature, precise measurements, safety management, cooling system, interface for external components [].

As an existing example we can point out the SMA Flexible Storage System, which can work with almost any lead acid or lithium-ion battery from major manufacturers, such as LG, Sony, Samsung, SAFT, Akasol, Leclanche and Dispatch Energy [].

Summary

The application areas, scenarios and technologies raise different challenges for developers that intend to realize smart home services.

Hardware and appliances consist the first barrier. Smart homes should bring together branches that have been standalone until now. Hardware from different producers uses different communication standards and technologies, managing interoperability of the devices is a big problem.

In addition average lifetime of the appliances are limited. Besides the problem of interconnecting, the challenge to add new devices, replace old ones and implementing new technologies should also be possible when it comes to smart homes.

Many of the scenarios in a smart home are based on the user’s location, the problems in determining the exact position should not result in the malfunctioning of the system and it should be as non-intrusive as possible, by meeting special requirements of security and privacy.

Also issues might be raised by the human-computer interaction. Some functions might be able to be controlled by a complicated sequence of steps, which by some members of the family cannot be set. The user interface needs to be as simple as possible, so that the user can benefit from every setting.

As it is also presented by the figures containing the load profiles of households and PV systems, the household consumption is not synchronized to the PV system’s power generation. In order to become more efficient there are two possibilities. Store the energy in storage units and shift the loads of the devices.

The following chapters will present the aims and goals of the energy management systems. Also, the developed algorithm, which provides control over the distinct load profiles.

Energy Management System

An energy management system (EMS) is a system with the purpose of monitoring, controlling and optimizing the energy consumption.

The term Energy Management System can also refer to a computer system which is designed specifically for the automated control and monitoring of those electromechanical facilities in a building which yield significant energy consumption such as heating, ventilation and lighting installations.

Load management, also known as demand side management (DSM), is the process of balancing the supply of electricity on the network with the electrical load by adjusting or controlling the load rather than the power station output. This can be achieved by direct intervention of the utility in real time, by the use of frequency sensitive relays triggering circuit breakers (ripple control), by time clocks, or by using special tariffs to influence consumer behavior. Load management allows utilities to reduce demand for electricity during peak usage times, which can, in turn, reduce costs by eliminating the need for peaking power plants. In addition, peaking power plants also often require hours to bring on-line, presenting challenges should a plant go off-line unexpectedly. Load management can also help reduce harmful emissions, since peaking plants or backup generators are often dirtier and less efficient than base load power plants. These technologies are constantly under development [],[].

In order to inexpensively generate solar power and substitute the utility grid, systems providing intelligent and automatic energy management have key importance when it comes to renewable energy supply. This importance is even rising as energy transition is progressing.

Energy management systems provide all day control and programmable power output for the photovoltaic system, so they will take over the properties of power plants. By the advance of technology, these systems will also be able to continually compare prices of the supply and demand for power.

Later on, besides solar PV systems, heat pumps, thermal energy storage and electric vehicles can be integrated. The transition has already started and by the continuous improvements and increasing compatibility of devices from different manufacturers, smart home will not only mean smart phone controllable household items, but independent homes from the energetic point of view, with low energy costs [31].

When comparing the load profile of the PV system’s power production to the load profile of the household’s consumptions presented in the figure below (Figure 3.1), it can be observed that the time intervals do not match.

While the power generation peaks of the photovoltaic system are during noon and afternoon, the peaks of the power demand are in the morning and in the evening.

This brings along the need adapt energy management methods, in order to balance out the loads. Such measures can be: load shifting to earlier or later times when there is enough power generated by the PV system (see Figure 3.2), to integrate storage systems (batteries, electric vehicles) which can supply energy for the devices which have specific functioning times. Another recommendation is the consideration of variable tariffs, energy provider companies differentiate energy costs by several criteria, such as power demand level, night or daytime, weekdays or weekends.

Figure 3.1: Comparison of PV power generation and household consumption

Figure 3.2: Load profile after implementing the load shifting method

Based on the above mentioned facts, an own algorithm was created, which has the intention to investigate solutions to the existing energy management problems. In the next chapter the detailed description can be found.

Algorithm

The main purpose of this thesis is to create a method to reduce the energy consumption and to create a way to influence a household’s load profile, in order for it to be in concordance with the load profile of the photovoltaic system, or to become independent from the grid with the additional help of a storage unit, in this case a battery.

For this, a behavior based efficiency algorithm was created in MATLAB, which relies on the consumers’ habitual behavior but also on one-time behaviors and allows the user to be constantly able to monitor the daily consumption of the working appliances, to change the status of the devices, follow the load profiles of the photovoltaic system, the battery and the cumulated or separated consumption of every utility. By the continuous monitoring of the consumption, not just the user behavior can be changed, but it can contribute to the changing of the market conditions as well as to the energy price evolution.

General presentation

The main goal is to create transparent load profiles, which are easy to control and let us get deeper knowledge about the general behavior of a typical household. For the analysis detail information is needed. Individually from each electrical device, data is required about how, when and how long it is used. The more familiar we are with the users habits, the more personalized energy management system can be built up, which results in not just more energy efficient behavior, but lower costs, balanced grid and cleaner environment.

The algorithm is developed with the scientific programming language MATLAB from Mathworks® []

MATLAB is a high-level language and interactive environment for numerical computation, visualization, and programming. It allows to analyze data, develop algorithms, and create models and applications.

MATLAB is suitable for a range of applications, including signal processing and communications, image and video processing, control systems, test and measurement, computational finance, and computational biology.

Currently, in order to determine the costs of energy, the consumption of households are realized by energy meters. Even though the smart meters are able to create power profiles, it is related to the total power consumption, while in the interest of changing the daily behavior we need to be aware of the consumption of every device, any time, separately and cumulated as well.

Therefore the created algorithm can build up the daily load profile of every device, every day of the year. By saving the data, we can periodically compare the performance in time, easily evaluate and draw conclusions about further possibilities to improve and become more energy efficient.

Even though every household has a different mixture of appliances, there are several common items which are present in today’s typical houses.

The algorithm’s basis consists of predefined load profiles of several largely available household items, as they in previous chapters were already presented. These load profiles are following the operation of the devices minute by minute, which will allow accurate results.

To create a general idea about the time of use of the devices, a survey from the laboratory of power systems and energy supply at Fachhochschule Südwestfalen Soest [], was taken into consideration.

The questionnaire surfaces information such as time duration of device usage, frequency of usage. These results helped in creating a general opinion about the energy consumption of families, from one to more than five members, in making distinction between summer and winter behavior, as well as weekend and working day profiles and offering deeper knowledge where can changes be made.

The information gathered also shows that devices related to entertainment and home office are common to be represented by more than one device. By knowing which device is in use, we were able to create operating cycles for each device which then contributed in building up the daily profiles.

After getting familiar with the user behavior, an energy management system has to be developed and energy sources and storage systems has to be implemented.

The algorithm considers a photovoltaic system as energy source and as storage unit a battery.

The construction of the program allows extension of the storage system with another battery or with an electrical vehicle.

The management system is shifting the load profiles of the devices by a predefined criteria. As it was mentioned in Chapter 2, we can distinguish variable and non-variable devices. The program verifies, to which category belongs the functioning device, and if there is not enough PV power and the device is variable, it recommend to shift the load to other time intervals.

By the end of the day, the program also calculates the generated costs and incomes of the day.

If there is additional PV power and the battery is fully charged, power will be supplied to the grid.

The algorithm considers appliances such as: refrigerator, washing machine, dish washer, coffee machine, TV, laptop, hair dryer, clothes dryer, lights and oven. Also, the list can be extended by additional devices, which are present in the house.

Basic Structure

The basic structure of the algorithm consists of two Matlab files.

The first one, as it is shown in Figure 4.1, contains several sub functions, gathered in the main function. In this, in the first step, a minute by minute update takes place, where it is checked which device is running, which, is then followed by the calculation of the load profiles and costs.

The constant update of the status of the devices, practically allows us a real time control over the appliances, consumption and cost.

The other Matlab file, see Figure 4.1, acts like a user interface and allows the user to change the status of the devices, connect other storage devices to the system and also, offers the possibility to study the load profiles of different appliances, the cumulated load profile, as well as the power and energy profile of the storage system and the status of energy supplied and drawn from the grid.

Figure 4.1: Basic structure of the main algorithm and user interface

Structure of the Algorithm

This chapter is focusing on the understanding of the created algorithm. As above mentioned, the control over the program is realized by two files. The first one is responsible for several calculation and includes separate sub functions for exact cost and consumption determination, while the other one provides the data for the main function and offers monitoring possibilities.

Main function

The main function, represented in Figure 4.2 entitled “main” is responsible for the running of the whole progress. Here are called the sub functions, in the precise order of runoff and purpose.

In the first step some initial pieces of information are required, such as the dimension of the photovoltaic system and the number of people who live in the house. This is needed for setting calculation parameters, determination of standby coefficients, initializing time and date and for the selection of the appropriate PV power profile.

This step is done in the first sub function of the main algorithm, called “offline_config1”.

In the main function a run time file provides the functioning of the program for a whole day. The current state of the algorithm requires initialization of date. This is important because the user behavior on weekdays is different from weekends, also due to the weather conditions the power generated by the PV system is very unstable. This feature, with the availability of weather prognosis can be useful in planning load shifting, also in further versions of the algorithm, the program will be able to automatically determine the exact date and time.

The weather prognosis can be taken from online databases and updated in predetermined time periods, having exact data will allow changes in the planning of device usage.

.

Figure 4.2: Structure of the main function

As already mentioned, sub function Offline Configuration 1 allows the user to enter the required data for the program to work. Information such as dimension of PV system, date of the year and number of people leaving in the house has to be introduced.

Sub function Offline Configuration 2 is needed to generate structured arrays for the devices, storage system and grid. These structures are needed for parameter configuration and contain information such as name of device, load profiles. The adoption of arrays also simplify and optimize the algorithm, they can be saved as historical data, extended with further cells and calling the stored data in them in other functions are more easier.

Currently, the block for devices contains the next fields:

Name – indicates the device;

Load_prof – contains the measured load profile of the device in a matrix.

Priority – indicates if the use of the device can, or cannot be shifted to a later time;

Stat – indicates the current status of the device, whether if it is working or not;

Daily_profile – builds up a daily load profile for every device, indicating when was the appliance working during the day;

Load_length – is vector, indicating that in a cycle how long was a device working;

En_cons – indicate the amount of energy consumed by the device up to the present moment

The storage array contains field for the next characteristics:

Name – name of device;

P – power profile of the battery;

E – energy profile of the battery;

Stat – indicates if the battery is present or not;

The grid block is built up from:

Total_en_supply – the amount of energy supplied to the grid up to the present moment,

Total_en_taken – the amount of energy drawn from the grid up to the present moment;

Total_en_tr – the overall balance of the energy transit up to the present moment;

The information regarding the load profiles are given by the measurements (see Chapter 2.1), based on the mentioned survey (see reference nr. [93]), which gives information about the times when certain devices are used in households. However, the survey does not mention how many lights are working or how many oven plates are in use when cooking, so for valid information standard average values have been considered, which then, based on the number of residents were multiplied with a certain coefficient. This method was applied in consideration of the standby loads as well.

The configuration of these profiles is also done in the offline configuration, which later, when the system will be connected to a real household, will get the profiles by direct, real time measurement.

After configuring the necessary data, the program enters a while loop, in which, by user defined settings the load profiles will be built up and costs will be calculated. This loop will represent the real time workflow, since it starts running in synchronicity with the program and its calculations. The loop runs minute by minute and does all the tasks in every cycle.

In the first step the program checks, the status of the device and verifies if the appliance is turned on or not. The constant update is done by the sub function “online_config”.

At the current moment, since the program is not connected to a real household, the status of the appliances are given by the user in the other Matlab file, which acts as a user interface and was introduced previously. If the system will be connected to a household, the configuration will be taken over and done automatically by the program.

The settings are stored in a “.mat” file, which is then accessed by the sub function found in the main file. Due to the fact that the switches are completely user dependent, the update takes place every minute.

The configuration is then followed by the sub function “length_counter”, which is responsible for building up the current and daily profile of the devices. This function loads the measured load profiles of the working appliances and implements them in current time. The power consumption is saved to the corresponding array cells of the device. On the other hand, the sub function measures how long has the device been working and calculates the cumulated energy that was consumed up to the present moment, by every device, separately, which is also stored in the structured array.

Figure 4.3 shows that regularly households use their appliances either in the morning, before going to work, either in the evening, when the come home. The function mentioned above, builds up these daily profiles.

Figure 4.3: Typical time intervals for using the washing machine

After calculating the separate load profile for every device in particular, the total consumption is calculated. This is done in sub function “load_profiles”. In addition to the overall consumption profile, which is the sum of all the devices that are working at the very moment, (see Figure 4.4) two other profiles are created, one which represents the consumption of devices that are not flexible and another which describes the behavior of flexible devices and whose functioning will be later shifted.

Figure 4.4: Cumulated load profile of a household

Figure 4.5: Cumulated load profile of non-flexible devices

Figure 4.6: Cumulated load profile of flexible devices

Energy Management

The above mentioned functions are responsible for determining the user behavior and the loads of the household, but in the creation of energy management systems further considerations are needed. As stated before the goal is to have grid independent households, where consumers will be able to cover their own energy needs. Therefore, own energy sources are needed, for example, PV systems. In the algorithm a photovoltaic system is implemented.

In order to manage the energy consumption it is needed to know how much power and energy is provided by the PV system as well, this is related to the weather forecast and capacity of the PV system, the algorithm calculates the daily profile.

Another key element in the energy management, is the presence of storage systems. In this case, the algorithm considers a battery. Its dimension is defined by the user, in the previously presented offline configuration. In the following the recommendations and the used optimization method are presented.

For maximum performance, firstly the self-consumption needs to be optimized, independently from the cost.

Self-Consumption optimization

As it was previously presented, devices can be categorized by their capability of being shifted to other time intervals. By load shifting we can reduce energy wasting and increase independency from the grid. In addition to this, using the devices during daytime, when there is enough energy available from the PV, considerable amount of costs can be saved.

The algorithm distinguishes two of device categories:

Flexible devices that can function independently from the time of day and can operate when lower energy tariffs are available. These are appliances such as washing machine, clothes dryer, and dishwasher. They can function when the habitant is not present, so they offer the possibility to be shifted.

Non-flexible devices are those, which strongly depend on user comfort and are influenced by exterior circumstance, time of day, working schedule. In this category we can enumerate the coffee machine, TV, laptop, lights, and oven. These devices need the presence of the user, so their functioning intervals cannot be changed.

The sub function “grid_stat” is responsible for the device’s energy supply. This means, that it verifies if there is enough energy generated by the photovoltaic (PV) system for the device to function. If yes, it will draw power from the PV system. If not, it will check if there is enough battery energy.

The battery status is calculated in the sub function entitled “storage”, which, as the status of the devices, is updated minute by minute. If the demand of the device is higher than available in the battery, the system will draw power from the grid.

On the other hand, if there is more energy available than needed, the system will check the status of the battery and if it is not full, charging will take place, in the other case, the surplus will be fed to the grid.

Due to the fact, that the program intends to reflect the current situation and behavior of households, the algorithm will follow the orders of the user, regardless of the device type. However, it also builds up a scenario, which is more economical from both energy, both cost point of view.

After turning on the device, the algorithm will evaluate if it’s flexible or not.

If the device is flexible and there is not enough PV energy available, the algorithm will shift the appliance to another time interval, when there is enough. If there is no such interval during the day, the program will commute the item to an interval where the difference between the demand and production is the lowest. In this case, the remaining demand will be lower, so the storage system will be able to supply the needed amount of power.

If the device is not flexible, the algorithm will continue to run with the generic settings and will automatically draw power from the battery or grid.

This scenario can be monitored as well, (see Figure 4.6 and Figure 4.7 ) and its intention is to draw a comparison between the two cases and to demonstrate how much energy can be saved by changing the user’s attitude.

The figures are very suggestive and they indicate that just by simply turning on the devices, that are not strongly connected to the user’s presence, in times when there is power generated by the photovoltaic system, great amount of energy and money can be saved.

Figure 4.7: Actual power consumption profile of a household

Figure 4.8: Balanced load profile of a household

Costs of Energy

At the end of every day, the program will calculate the total expenses and incomes generated during the day.

If there is more photovoltaic power than needed, the supplied energy will generate incomes, while drawing power will generate costs.

Cost calculations are done by two tariff models. In the first one, the price of the consumed energy is the same during the whole day and the same prices apply, without load limit.

In the second case, there is a load limit. If the power demand is above 1.2 kW, the energy has a different price range, than in the case when demand is below 1200 W.

Note:

The following assumptions were taken into consideration while writing the program:

The cost of energy supplied to the grid is considered cheaper than the cost of the energy taken from the grid.

The tariffs that were used in the calculations are the following:

Case 1:

Taking energy from the gird: 0, 28 Euro/kWh

Supplying energy to the grid: 0, 1368 Euro/kWh

Case 2:

For power demand below 1200 W, the cost of energy is 0, 23 Euro/kWh

For power demand above 1200 W, the cost of energy is 0, 28 Euro/kWh

Supplying energy to the grid: 0, 1368 Euro/kWh [;]

Directly used power is more efficient than stored power

Due to the fact, that batteries have losses while charging and discharging, energy can go to waste. If using instantly the generated power, these losses can also be saved.

If the battery is full, the remaining energy is being supplied to the grid

Supplying energy to the grid can generate extra income and can help in balancing out the grid energy prices.

The costs were calculated for the cumulated load profile presented in the figure below:

Figure 4.9: Cumulated load profile for cost calculation

Costs with case 1

Figure 4.10: Screenshot of cost calculation through method 1

Costs with case 2

Figure 4.11: Screenshot of cost calculation through method 1

Comparison

The final costs are calculated for a single day. As it can be seen in Figure 4.10 and Figure 4.11 the costs are lower when the differentiating taxation profile is in force. Changing the user behavior can lead to serious savings, especially when calculations are for a whole year.

By multiplying the final values with the number of the days in a year, can add up to savings to around 600 Euros/year.

Also, the cost calculations refer to cases without implemented storage systems, which can additionally decrease the expenses.

Summary of the developed energy management system

The intent of the algorithm is to offer a deeper knowledge about the consumption of the households and to point out the current imbalance between the energy sources and user behavior.

This algorithm is the first step to create systems that are able to efficiently use the power generated by the PV system, without creating user discomfort or completely ignore the user’s wishes.

The construction and structure of the program is easily understandable, which is a great benefit because it leaves room for improvements. Further extensions can be made, by adding new sub functions or Matlab files to the main function, also, not-needed parts can be removed. This means that new devices can be added to the system, databases can be connected to it, weather forecasts or more sophisticated energy management systems can be implemented.

Market Analysis of the home automation industry

As technology advances in time, it starts to take over greater parts in our lives, today there are no homes without computers, internet, home cinema or other digital technologies. Each generation brings new concept and ideas to the market, new issues, frustrations and opportunities. The latest wave of technology is energy related. Applications at this level are not just comfort related any more, they take into consideration the environment.[7]

Smart home systems offer control over following categories: lighting and window systems, security and access control systems, heating and cooling, home appliance control, home office and entertainment systems, healthcare and energy management systems. []

Home automation and market development

Even the concept of home automation has been in existence for a long time, it failed to significantly grow in the 1990s, when the first commercial solutions were made available, due to prohibitive costs, poor user-friendliness, unconvincing benefits for end-users, proprietary approaches and erratic reliability. But in the last few years the market experienced a major growth. Regulations introduced by governments and the increasing interest to save costs among home owners are the primary contributing factors in the profound change of the market.

The home automation and controls have not only led to power savings but also contributed to a more comfortable life and enhanced the living standards.

The market for home automation and controls is segmented into lighting control, security control, access control, HVAC control, entertainment control, communication protocols, standards and data distribution, outdoor control, and other controls. []

The components used in the home automation system are designed mostly by expert engineers and manufactured for a limited number of appliances, therefore they have high prices and a narrow area of use.

Technology companies produced control systems for their own line of products, while in a house the control should be brought together for different appliances, from different manufacturers.

Even nowadays, control system security may be difficult and costly to maintain, especially if the control system extends beyond the home, for instance by wireless or by connection to the internet or other networks

Ongoing costs include electricity, to run the control systems, maintenance costs for the control and networking systems, including troubleshooting, and eventual cost of upgrading as standards change. Increased complexity may also increase maintenance costs for networked devices. Cloud-based services supporting an installation may also entail fees for setup, usage, or both. [11]

In developed countries, home environments are increasingly getting equipped with devices. For example, in 2008 94% of all German households had a TV screen, 70% also a DVD-player, 86% had mobile phones, computers and laptops were present in 75% of all households. [,66]

While in 2011 in the U. S. 71.7% of the population reported accessing the internet from home, today, 83% of households include HDTVs (doubled since 2009), according to the research of “Chetan Sharma Consulting” the average U.S. household owns five connected devices to the internet. It is also estimated that among 70-80% of these devices can access via wireless connection [].

Worldwide, from 2011, when there were 9 billion connected devices, the number raised to 10 billion, today. This increase is expected to continue in the future, as people tend to adapt to new technologies and devices very fast.[] This is significant to the home automation market, since internet connectivity is the first step when it comes to implement such systems.

On the other hand, the advance of technology and the evolvement of the power of devices bring up new problems. The product life cycle decreases, while more features are delivered than the user actually uses. This is either because he is not aware of the possibilities, either due to the fact that the operation is too complex. Although, an important aspect, when choosing and adapting a new technology is the costumer’s wish to stay in control. This wish can appear in several levels:

Control over usage: Customers want to be in charge whether to use a particular device, application or service at all.

Control over operation: Customers want to control the way in which a particular device, application or service is used.

Control over time: Users set the amount of time they are spending on the operation of a particular device, application or service.

Control over combination: Customers want to choose the applications and services that are part of their smart home solutions.

Control over evolution: Customers decide when and how their smart home solutions will be upgraded or extended [].

Implementing smart home solutions means that the user will have to hand over some of the controlling to the system or service. In order to give the user the feeling of remaining in control, smart home systems have to provide sufficient information to the user about the current action and highlight its benefits. If a user understands why the system has set a device to a specific operation, and if he has the possibility to overwrite this decision, he will certainly tend to accept the loose of control.

Market potential

While there is still much room for growth, according to “ABI Research” [], 1.5 million home automation systems were installed in the US in 2012, and an uptake could see shipments topping over 8 million in 2017. As resulted of the research of “Berg Insight”, 36 million homes in Europe and North America will be smart by 2017. []

The European market is still in the development phase, at the end of 2012 there were 1.06 million smart homes in use. By the end of 2013 Europe had about 1.45 million systems and it is expected to reach 17.4 million systems by 2017. [68]

“Markets and Markets” forecasts that automation in Europe will continue growing further to 2016 with a Compound Annual Growth Rate (CAGR) of 13%. The worldwide home automation and control market should reach from $16.9 billion in 2011, $35.6BN in 2016, with a CAGR of 16.1%. Such growth is increasing customer demand for energy efficient solutions, improved security and demand for handy systems [].

The market was dominated by the entertainment control segment, with a percentage of 22% from the revenues of 2010. Communications, standards and protocols and the outdoor control segments will also grow fast, with an expected CAGR of 23.7 % until 2016.

Between years 2011-2016 systems in Asia will also present a growing popularity, with an expected CAGR of 19.9%. [104]

Researchers at Massachusetts Institute of Technology (MIT), developed kitchen systems that by studying user behavior, such as cooking, eating and the frequency with which they open the fridge, will gather up information and create a home automation system that will be able to balance the technology and human interaction. [7]

Household electricity prices have risen by 4% a year between 2008 and 2012 as a result of levies and taxes linked to renewable energy, according to the Commission. []

The U.S. market for home automation experienced a growth of 6% between the years 2010-2011. In the longer term, according to forecasts, this growth will be even stronger, up to 10.6 annual growth [].

The market is going through a solid growth phase, marked with complexity and immaturity. There are variations in growth pattern across different geographies. These variations exist in terms of technologies used and applications preferred [].

It’s clear that the smart home market is becoming increasingly measurable as it grows, fact proven by concrete deals like Google’s recent acquisition of Nest. Judging simply by the investments of companies like Google, Microsoft, and other industry giants, it’s easy to see that the home automation industry is the next big step in the people’s lives [].

With Ford at the helm, the MyEnergi collaboration includes global heavy-hitters such as the power management company Eaton, solar industry giant SunPower, home appliance company Whirlpool, and semiconductor innovator Infineon, as well as smart thermostat pioneer Nest Labs [].

In Figure 5.1 it is presented how home automation systems were adopted in homes. In the beginning, systems were covering solutions for gardening. By the evolution of time, these systems came step by step closer to our homes and they are even capable of offering health care and assistance of living.

Figure 5.1: Evolution of adoption of smart home systems [110]

The adoption of smart home solutions is influenced by several factors. The demand analysis has six relevant spheres of influence:

Price: level and transparency of end-user prices with respect to the first-time purchase and the day-to-day usage.

Value added: concreteness, availability and relevance of the primary features of a smart home solution.

Security: data protection, privacy protection and fraud prevention.

Durability: compatibility, standardization, modularity, extensibility, quality and persistence of the complete system and its components.

Simplicity: ease of installation, ease of use and ease of experience.

Outer appearance: visual integration into the home environment with regard to aesthetics and design [67].

Home automation and renewable energy

Home automation is strongly connected to the renewable energy market and the introduction of smart grids.

In this field a strong rise in demand can be observed, due to the growing concern to protect the environment and issues related to energy security, government regulations and initiatives, coal plant retirements, increasing interest in cost efficiency.

Renewable energy technologies like wind and solar have been heavily subsidized since the EU set a target in 2008 of sourcing 20% of energy from renewable sources by 2020 [71].

New economic models are now emerging. In the UK the feed-in-tariff is encouraging take up of micro-generation technologies by both homeowners and commercial organizations. The Green Deal aims to support retrofitting by providing loans that will accompany the built stock (rather than the borrower) and enable investment costs to be paid off from energy bill savings. Berkeley had a similar system for a time but this was adversely affected by reassessments of property risk in the aftermath of the US mortgage crisis

Sun energy is the largest available renewable energy to humans while water and air are also some important alternatives for power generation.

The ideal smart home concept contains a renewable energy source, in most cases photovoltaics, a storage unit (batteries or electric vehicles) and an energy management system.

Between years 2002-2012 photovoltaics met a 48% annual rise, and in Europe contributed 66% of the total cumulated installations.

The factors lined up against the continued strong growth of photovoltaic (PV) in Europe and around the world are formidable: a continuing economic and financial crisis; industry consolidation; a global market rebalancing; political and regulatory instability as governments reconsider their commitment to renewable energy sources and climate-change mitigation. But even in the face of all of this, the following report shows how, under the right conditions, the prospects going forward for solar PV – a clean, safe and infinitely renewable power source – remain solid.

Driven by local and global energy demand, the fastest PV growth is expected to continue in China and India, followed by Southeast Asia, Latin America.

Home automation technologies are viewed as integral additions to the Smart grid. Communication between a home automation system and the grid would allow applications like load shedding during system peaks, or would allow the homeowner to automatically defer energy use to periods of low grid cost.

Green Automation is the term coined to describe energy management strategies in home automation when data from smart grids is combined with home automation systems to use resources at either their lowest prices or highest availability, taking advantage, for instance, of high solar panel output in the middle of the day to automatically run washing machines

Potential clients

As it is presented in the figure below, home automation solutions can be divided in several focus groups.

Among potential clients we can enumerate the owners of flats and houses.

The adopted solution can differ from one client to another based on the following criteria: actual status of installed equipment, whether the home is located in a building or it is a house, budget, age, number of people leaving together.

Figure 5.2: Possibilities offered by the home automation industry

Source: http://www.rolandberger.fr/media/pdf/Roland_Berger_taC_Home_Automation_20140205.pdf

Home automation companies can specialize either in fulfilling just segments of the home automation markets or can offer whole house solutions.

Potential clients can be grouped in three categories: “demanding for simplification”, formed by users who would like to adopt automation solutions to simplify everyday life and are looking for tangible and familiar system components.

The other category is composed by clients “demanding for variety”, who appreciate high grade and innovative products and are willing to pay higher prices for well-known brands.

Customers belonging to the group of “demanding for options” are looking for modularity and the possibility to further extend the system with new appliances [66].

The most attractive sector is related to the entertainment and security sector. The system can set up scenes for movie nights, turn off the lights, turn on the home cinema and if the phone rings the movie will be put on pause.

The system will automatically lock the doors at night or if the tenant is gone for a longer period of time it will occasionally turn on the lights or the TV.

A typical 4 member family can be interested in services that offer childcare, such as monitoring whether the baby cries, housekeeping, setting the washing machine to times when the kids are awake or nobody is home.

If the tenant belongs to the elderly, healthcare and assisted living plays an important role of the everyday life, the system will send reminders that the medicine has to be taken, keep track of the blood pressure, offer medication possibilities for different symptoms of illnesses.

Home automation is also very important from the users comfort point of view. It not just allows to turn off the oven from the living room, but also offers a hint of luxury and sophistication due to the numerous modern interfaces.

Competitors

Among the player of this market we can differentiate:

Direct stakeholders, who already have equipment installed in the home and see home automation as a way to strengthen their current value proposition or to gradually shift their positioning:

Utilities: to better manage energy consumption/costs (demand-response capability), offer new services to their customers and understand them better;

Decorative specialists: to offer higher-value products (glass, lights) and new services related to decorative elements (remote control, etc.);

Security operators: to increase their equipment level and develop subscription services;

Communication & entertainment: to increase data traffic, offer a differentiating factor and control the main final user interface.

Indirect stakeholders – do not have devices widely installed at home, but could use home automation to get at the best positioning:

Healthcare: e-services, and alternatives to hospitals or nursing homes;

Housekeeping: direct connection between appliances and suppliers (from the fridge to the supermarket) and replacement of human services (ex: automated vacuuming);

Monitoring children: parental control services, replacement of human services (ex: basic child care).

Home automation is seen from two different angles. On one hand, it is a growth opportunity, by expanding the offering, having a positive impact on image and recurring revenues. On the other hand, it is also a key threat to current operations, as it opens the door to new entrants and challenges the current offering and business models []

Figure 5.3: Players in the home automation industry

Source: http://www.rolandberger.fr/media/pdf/Roland_Berger_taC_Home_Automation_20140205.pdf

Smart home solutions consists of a wide range of hardware and software technologies. This, together with the continuous market growth and interest among potential clients, attract many new competitors to the market.

Beside traditional whole-home solution vendors such as Crestron, Control4, Gira, Jung, telecom operators, security service providers, energy companies and other vendors are entering the industry.

Companies with years of experience, such as Honeywell, Whirlpool, Phillips, Sony, LG are also developing their own systems and design home appliances that are working with their very own home automation application [69].

This brings new problems, this area has to face.

The first is complexity. Installing a connected home is a complex procedure, which has been plagued by a lack of standards and general difficulty for the end user. Also, in Europe, with utilities eager to sweeten the deal for customers by joining forces with smart home designers, this may be changing.

The second is fragmentation. There is no guarantee that different devices and hubs will interoperate. All of them use different protocols and will not work well together. That means that specific point solutions around, have been quite successful, but the wider connected home hasn’t really taken off.

In many ways, this is where smartphones can work their magic. While individual smart appliances may not be able to communicate with each other, they can communicate with an iPhone or an iPad. The fact that smartphones can be used as remote controls for a very wide variety of things is a forte for the smart home market.

But that still doesn’t solve the third problem: inertia. While there are market drivers, such as security or wanting to reduce home energy bills, they are easy to put off and will often depend on people moving home. While most households may think that a connected home solution is a good idea, there’s a big difference between that and them actually installing this solutions into their own home.

This is especially true considering that smart home technology is designed for newly built homes or refurbished ones. Europeans live in old houses, and they don’t change them as often as Americans do [].

In the following the analysis of the market’s main competitors is presented.

Globally the most important market players include Crestron Electronics, Inc., ADT Corporation, AMX LLC, and Control4 Corporation; accounting for more than 35% of the market share. The rest of the market is distributed among companies that are specialized in specific applications and those with generalized solutions, such as Lutron Electronics Company Inc., Honeywell, ABB Ltd., Nortek, Inc., Vantage Controls, Schneider Electric SA, SoftAtHome, LivingTech [].

In Europe, key competitors are Crestron Electronics, ABB, Eaton, Loxone, Prosyst and appliance manufacturers such as Miele, LG, Bosch or Sony [].

Crestron Electronics is on the market for more than 40 years (founded in 1968) in the United States of America and it is the global leading manufacturer for advanced home automation and control systems, providing control solutions to the entire home. The developed hardware includes programmable controllers, touch panels, keypads [].

ABB group is a multinational corporation, founded in 1988, headquartered in Switzerland, with the main operating focus in automation. With a global revenue of 40 billion dollars in 2011, the company is present in 100 countries. The low voltage division develops KNX systems (communication protocol for intelligent buildings) that integrate and automate ventilating, security and electrical installations [].

Eaton Corporation, with the headquarters in Dublin, Ireland is a power management company, present on the market since 1911. With a combined revenue of 21.8 billion dollars it is present in more than 170 companies. For residential and small commercial applications the company developed a wireless control system, named xComfort, which provides centralized control over all the electrical equipment, in order to maximize comfort (lights, heating, cooling, remote control via PC, phone and tablets), security, safety and savings [].

Loxone is a highly growing Austrian company, founded in 2009. The main field of activity is implementing a Miniserver based home automation system, capable of providing control from any device, PC-s, smartphones, tablets. During a three year activity the company has sold over 21000 Miniservers. The main operating markets are Germany, Austria, Switzerland, United Kingdom and Spain but the company sold products in more than 60 countries [].

Prosyst is a company founded in 1997 in Germany, and offers software platforms for service providers and device manufacturers. By 2009, the company’s OSGi (open service gateway initiative) implementation was sold over 4.000.000 times. Among product specification we can enumerate: full remote management support, configuration management and diagnostics. It is ideal as a common software platform for distributed target devices. Strong collaboration exists with manufacturers such as Miele, Samsung or Bosch [].

As the sales continue to grow new competitors enter the market, which include start-ups, and large telecom and cable companies as well [].

Summary of analysis

Until now the development of home automation applications did not “take off” quite as rapidly as expected. The main driving forces in the current development and deployment of home automation have to be identified. Saving energy, increasing of comfort and simplification of the running of the home could be it. In addition the need for health and social services for specific target groups could also support turning our homes into smart homes.

The tendency of the market is a positive one, its dimensions are world widely constantly growing, which is demonstrated by several factors. Big appliance companies develop their own home automation systems, cooperation between car companies and white good manufacturers are started, IT companies purchase startups from the home automation industry.

The main spheres of influence for consumers are increasingly favorable.

As technology improves, prices of the systems are lowering, new functions are being introduced, the security and privacy is increasing, while the control of the systems are getting simple and easily manageable, since it is realized from smart phones and tablets.

As barriers, we can mention that even though prices follow a decrease, installation of these systems is still costly and a skepticism among home owners are still widely available.

While a large part of population in Europe, live in flats and old houses, where installation of these systems can be difficult or more expensive.

The above presented facts, show that the market for home automation systems has a great potential, with many possibilities to improve from technical and economical point of view as well.

Summary

This paper serves to purpose to get a deeper knowledge about the current and future status of the smart home market.

As it has been previously presented, in the contemporaneous sense, when considering smart homes, the primary goal is to increase users’ comfort, by being able to remotely control segments in a household, such as heating, lighting, security.

By the pressure of the world’s energy problems and government incentives this perceptions will change in the future and the appellation of smart homes will also include energy management systems and will be able to become more independent from the grid. They will have installed own energy sources and storage units.

Applications that have implemented solutions to save money and energy start to appear on the market, but there are numerous challenges that need to be overcome.

One of the main problems is the lack of interoperability among different appliances. Smart homes should bring together and control branches that have been standalone until now.

The lack of knowledge of the devices and user behavior influenced the development of the algorithm presented in this thesis.

By using special functions, the program analyzes, how a household is working, which are its weak points, calculates load profiles, costs and by building up alternative scenarios offers solutions on how to become more efficient.

By offering important information and the possibility to continuously improve and extend it, the program can become a very flexible and precise energy management system for the future households.

As people become more and more concerned about issues related to the environment and household energy consumption, by analyzing the global market of the home automation industry we can draw the conclusion that it is steadily improving and it gains more and more interest in our everyday lives.

The above facts, show that the market for home automation systems is in its development phase and has a great potential, with many possibilities to improve from technical and economical point of view as well.

List of Abbreviations

List of Variables

List of Figures

Figure 2.1 Home automation devices [66] 19

Figure 2.2: Refrigerator load profile 23

Figure 2.3: Load profile of tumble dryers 25

Figure 2.4: Load profile of a washing machine 26

Figure 2.5: Load profile of a dishwasher 28

Figure 2.6: Load profile of hair dryer 30

Figure 2.7: Load profile of iron 31

Figure 2.8: Hot air ventilator load profile 33

Figure 2.9: TV load profile 35

Figure 2.10: Laptop load profile 36

Figure 2.11: Load profile of consumption in a one-person family 40

Figure 2.12: Load profile of consumption in a five person family 41

Figure 2.11: Installed PV systems in Germany by size 43

Figure 2.12: PV System on a rooftop and Inverter on the wall 44

Figure 2.13 Cost of implementing 4kW PV system 45

Figure 2.14 : Combined Heat and Power Diagram 45

Figure 2.15: Batteries for Electric Cars. Opportunities and outlook for 2020. 51

Figure 2.16 : Vehicle to grid concept 52

Figure 2.17: Vehicle to homes 53

Figure 2.18: Smart home application structure 55

Figure 2.19 – Loxone Home Automation Solution 57

Figure 2.20: Homechat application 58

Figure 2.21: Honda Smart House Concept 60

Figure 2.22: SMA flexible home manager system 61

Figure 2.23 : Load profile of a household equipped with the SMA Sunny Home Manager 61

Figure 4.1 Basic structure of the main algorithm 69

Figure 4.2: Basic structure of the second Matlab file 70

Figure 4.3: Structure of the main function 71

Figure 5.1: Evolution of adoption of smart home systems 78

Figure 5.2: Possibilities offered by the home automation industry 81

Figure 5.3: Players in the home automation industry 83

List of Tables

Table 2.1: List of appliances and their consumption 20

Table 2.2 Device Categories 21

Table 2.3 Lamp types 38

Table 2.4: Evolution in time of CHP technology 47

Table 2.5: List of commercially available battery types 49

List of Equations

(2.1) 19

List of References