ADMINISTRATIVE BUILDING IN TUNIS First YEAR MASTER DEGREE ENERGY ENGINEERING REALIZED BY : JOSHUA DELE BAMI DO HAMZA BEN AHMED 1. Introduction: As… [611213]

ENERGY OPTIMIZATION FOR
ADMINISTRATIVE BUILDING IN TUNIS
First YEAR MASTER DEGREE ENERGY ENGINEERING

REALIZED BY :
JOSHUA DELE BAMI DO
HAMZA BEN AHMED

1. Introduction:
As new progression accorded to regulate the use of energy, the optimization study project
applied for various sector of activities has the priority to be established, in order to reduce the
exhausted quantity and to adapt exactly the needed amount of energy that we should ensure
for residential or industrial building.
Due to the specific calculus developed basica lly from the energy balance analysis , this project
illustrate s how can we improve the use of the e nergy needed for the heat air and conditioning
system applied for an actual building located in TUNIS respecting the climatic and
geographic coordinates, the thermal class of temperature, and how can we propose various
solutions starting basically from the current characteristics of the building.
2. Description of the building :
The project is consisting an administrative building located through a ground level located in
TUNIS, so it’s belong the thermal class of temperature ZT1.
The thermal class of temperature is concerning the estimated external temperature when we
need to determine the required thermal energy inside the building ( High external temperature
estimated for the ZT1 is 45°C ) .

The thermal class of temperature according to the Ministry of Energy in Tunisia
The building sweeps a surface equal to 70m², respect ing an angular orientation of 25°
according to the north meridian.

The Administ rative department including the two areas in which we need to provide the
air conditioning system
The following table illustrates all the details describing the home:
Coordinate Value
Longitude 10°16
Latitude 39°16
Conditioning Air Surface 1580 m²
Angu lar Orientation 25°
City Tunis
Thermal Class ZT1

The distribution of the conditioning air surface is separated through two areas , in effect, we
can approximately consider that these two areas are not belong the building, then we develop
the energy bala nce fo r both of the two areas separately.

Room N°1 :
The room N°1 sweeps a surface equal to 950 m².
Coordinate Value
Conditioning Air Surface 950 m²
North Wall 106,4 m²
Ouest Wall 70 m²
South Wall 106,4 m²
Est Wall 70 m²
North Window 12 m²
South Window 12 m²

Room N°2 :
The room N°2 sweeps a surface equal to 630 m².
Coordinate Value
Conditioning Air Surface 630 m²
North Wall 88,2 m²
Ouest Wall 56 m²
South Wall 88,2 m²
Est Wall 56 m²
Ouest Window 10 m²
South Window 12 m²

These parameters are basi cally needed to develop the work starting by identifying the
configurat ion of the building, we have to determine the thermal characteristics assuming the
heat transfer submitted i nside and outside the building.
The carpentry:
The carpentry provided is of aluminum joinery type equipped with glazing having the
following characteristics:
Simple glazing with low emission 6 mm thick.
The heat loss coefficient (K): 4.27 W / (m² ° C)
Light Transmission Factor (TL): 0.88
Energy Transmission Factor (TE): 0.48 .
The wall:
Double wall as 35 cm of thickness , consisting of two hollow red brick walls separated by a
polystyrene insulation as 4 cm of thick ness. The heat loss coefficient k of such wall is
estimated at 0.56 w / m² ° C.
The roof :
Insulated roof with 4 cm of thickness composed of polystyrene . The heat loss coefficient k of
such wall is estimated at 0.68 w / m² ° C.

The thermal energy needed to be provided for the building, respecting the parameters and the
energy balances presented previously accorded to the thermal class ZT1 , is determined by
CLIPPERFORMANCE software as one of the main tools of calculation respecting the
Tunisian and AFNOR standards.
Such software needs to get the characteristics of the building as required INPU T including the
thermal characte ristics of the materia ls.
As a result , CLIPPERFORMANCE illustrates the result as the average req uired thermal
energy per m² during one year . According to the INPUT of the Building, we get as result :
Q = 61 kWh/m²
Q = (61 x 1580 ) / 3600 = 27 kW

The following figures describes the dashboard of the CLIPPERFORMANCE including the
INPU T related to the building, and the result .

CLIPPERFORMANCE DASHBOARD INCLUDING THE INPUTS
AND THE RESULTS

3. The solutions to provide the requir ed energy :
In order to ensure the required energy, we need to overestimate the quantity calculated from
CLIPPERFORMANCE as the following form :
Qestimated = 27 x 1 , 33 = 36 kW
Then , we can develop various kind of solutions, which could be integrated for the heating and
the air conditioning.

The split system:
Composed of an outdoor unit and an indoor unit, the SPLIT system known as air -air system is
considered the most frequently devises used for the residential and commercial requirement.
The following table describe the first proposal to ensure the required th ermal energy using
SPLIT system :
Equipment Thermal power Quantity
SPLIT System -Room 1
York 7 kw ( 24000 Btu/hr) 4 ( respecting 27kWh/m² for
950 m²)
SPLIT System -Room 2
York 7 kw (24000 Btu/hr)
3 ( respecting 27kWh/m² for
630 m²)

Advantages:
Adjusting manual ly the parameters of each devise
Simple Installation in the place that we choose
High Efficiency
The cheapest cost
Disadvantages:
Noisy system
Prone to technical damage
Electrical consumptio n:
Equipment Thermal power COP Electrical Power
SPLIT System York 7 kW ( 24000 Btu/hr) 3,65 1,92 kW

The chiller:
As one of the famous technology frequently installed in order to provide the required thermal
energy, the chiller system contribute to reduce or to increase the temperature inside a local, by

serving a certain flow of ‘’cold water’’ through internal unit then to inject or to throw a
certain q uantity of calories from the local.
The following table describe the second proposal to ensure th e required th ermal energy using
chiller system:
Equipment Power Quantity
Chiller -York 40 kW 01
Indoor unit -York 25 kW 01
Indoor unit -York 15 kW 01

Advantages:
It’s serving cold water as a cheap source of energy instead to put the refriger ant
High efficieny based on the closed circuit of the water circolator
Disadvantages:
High cost of insta llation
Not suita ble to work by speed variator

Electrical consumption:
Equipment Thermal power COP Electrical Power
Chiller S ystem York 40 kW 3,2 12,5 kW
Indoor unit -York 25 kW 3.3 7.6 kW
Indoor unit -York 15 kW 3.3 7.6 kW

The DRV system :
As a new technology appeared DRV are typically installed with an air conditioner
inverter which a dds a DC inverter to the compressor in order to support variable motor speed
and thus variable refrigerant flow rather than simply perform on/off operation .
Equipment Power Quantity
Outdoor unit -York 40 Kw 01
Indoor unit -York 25 Kw 01
Indoor unit -York 15 Kw 01

Advantages:
Updated system and adapted to work with speed variator.
Disadvantages:
High cost of installation
A huge amount of refrigerant
Electrical consumption:
Equipment Thermal power COP Electrical Power
Outdorr Unit -York 40 kW 3.6 11.11 kW
Indoor unit -York 25 Kw 3.3 7.6 kW
Indoor unit -York 15 Kw 3.3 7.6 kW

4. Comparison details :
Summarizing the details included in the study as the following table contribute to specify the
total cost needed for the proposal case s as the following table :
Devise Price s Estimated
SPLIT SYSTEM YORK 7 KW 750 EURO
CHILLER YORK – 40 K W 9500 EURO
OUTDOOR UNIT -40 kW 10500 EURO
INDOOR UNIT 25 kW 1500 EURO
INDOOR UNIT 15 kW 1000 EURO

According to these results, we can compare the costs for the three variants:
Variant Cost
SPLIT SYSTEM 5250 EURO
CHILLER 12000 EURO
VRV 13000 EURO

Consequently, the first variant is concerning the lowest cost proposed to integrate the heat and
conditioning inside the building, we note that the cost of the CHILLER and VRV proposal s
requires also the addition of the prices related to the pipeline and the fluid regulator.
In order to follow the functioning of all the proposals , we focus in this paragraph on the
evolution of the COP during the lifetime of the system.
Variant LIFETIME COP
SPLIT SYSTEM 10 Years 3,65
CHILLER 15 Years 3,2
VRV 15 Years 3,6

At this level, we consider as simple hypothes is that all the COP parameter tend to be nul
during the last year of the lifetime ’s devises.

Decreasing of COP COEFFICIENT during an estimated period of LI FETIME for the three variants,
prove that the SPLIT variant is not suitable for long working period despite the low cost of
installation

5. Conclusion :
 It is necessary needed to specify the energy required from various method in order to get
more proposals ensuring the same order of power with the lower consumption.
 Improving the efficiency is not meaning to reinstall the building and providing the new
technology, we can refer also to manage the operating mode, or to optimize quantity of the
devises neede d at home.
 We have to take care about the COP coefficient for the thermal system when we need
to size or to propose one variant, because it is not only the price that guides us to choose
one variant, our variant could be the lowest cost with the lowest lifetime working.
 Like CLIPPERFORMANCE , various software are becoming the main tool for the future
project, which refer to install smart system that adapt automatically the ideal climatic
conditions inside the home.

REFERENCE FOR YORK CATALOGUE :
https://www.daikin.eu/c ontent/dam/document -library/catalogues/as/air -cooled –
chiller/dwdc/Applied%20Systems%20Catalogue_ECPFR14 -400_Catalogues_French.pdf
REFERENCES FOR THE LIFETIME OF THERMAL EQUIPMENT :
https://www.hannabery.com/heat -pumps101 -faqs.sht ml
https://www.mcgarryandmadsen.com/inspection/Blog/Entries/2015/7/30_What_is_the_average_lif
espan_of_an_air_conditioner .html