Analytical and Comparative Study for Solar Thermal Cooling and Photovoltaic Solar Cooling in the MENA Region

TRNSYS simulations for Aswan-TSFH and Aqaba-TSFH respectively demonstrate that the maximum cooling load demand during summer season are: 13.9 kW and 15.3 kW; the annual cooling energy de

Younis Yousef Abidrabbu Badran

A Thesis Submitted to the Faculty of Engineering at Cairo University

and Faculty of Electrical Engineering and Computer Science at Kassel University

in Partial Fulfillment of the Requirements for the Degree of

Master of Science

in Renewable Energy and Energy Efficiency

Analytical and Comparative Study for Solar Thermal Cooling and Photovoltaic Solar Cooling in the MENA

Region

By

Younis Yousef Abidrabbu Badran

A Thesis Submitted to the Faculty of Engineering at Cairo University

and Faculty of Electrical Engineering and Computer Science at Kassel University

in Partial Fulfillment of the Requirements for the Degree of

Master of Science

in Renewable Energy and Energy Efficiency

Dr.-Ing Norbert Henze

Systems Engineering and Grid

March, 2012

Analytical and Comparative Study for Solar Thermal Cooling and Photovoltaic Solar Cooling in the MENA

Region

By

Younis Yousef Abidrabbu Badran

A Thesis Submitted to the Faculty of Engineering at Cairo University

and Faculty of Electrical Engineering and Computer Science at Kassel University

in Partial Fulfillment of the Requirements for the Degree of

Master of Science

in Renewable Energy and Energy Efficiency

Approved by the Examining Committee:

Prof.Dr Adel Khalil, Thesis main Advisor

Prof Dr Albert Claudi, Thesis main Advisor

Dr Sayed Kaseb, Member

Faculty of Engineering

Cairo University Kassel University Giza, Egypt Kassel, Germany

March, 2012

Deepest gratitude to my supervisor from Cairo university, Professor Dr Adel Khalil for his support and giving me the chance to carry out this research It has been a pleasure to work with this professor who has a high scientific competence and professionalism In addition I would like to thank my supervisor from Kassel university, Prof Dr.-Ing Albert Claudi for his available advice in this study Thanks to Dr.-Ing Michael Krause from Fraunhofer Institute of Building Physics - Kassel(IBP), who has guided and supported

me especially in the TRNSYS simulation and the thermal air-conditioning cooling design

in this study

I am grateful to Mr Salah Azzam and Mr Firas Alawneh from The Higher Council for Science and Technology National Center (NERC) in Jordan, who supported me in getting the meteorological measurement data for Aqaba city

Thanks to the German Academic Exchange Service (DAAD) for their financial assistance which made it possible for me to pursue the REMENA master program and this study Thanks to my teachers, friends and staff of the REMENA master program and IWES Fraunhofer Institute in Kassel for encouraging me during my work

Abstract

In this thesis, a comparison and analyses of solar thermal and solar photovoltaic (PV) air-conditioning technologies for a Typical Single Family House (TSFH) in two different MENA climates, Aswan-Egypt and Aqaba-Jordan, are performed The building cooling demand is firstly obtained from annual building simulation in TRNSYS software Based

on these simulation results, three scenarios are designed in order to compensate the TSFH’s annual cooling demand in each selected climate These scenarios are solar thermal air-conditioning with storage (absorption chiller), PV air-conditioning without storage and PV air-conditioning with storage The cooling compensation is simulated by Matlab-Simulink for each scenario

TRNSYS simulations for Aswan-TSFH and Aqaba-TSFH respectively demonstrate that the maximum cooling load demand during summer season are: 13.9 kW and 15.3 kW; the annual cooling energy demands are: 44,330 kWh/year and 43,490 kWh/year which represents 97.5 % and 96.3 % of the total annual energy consumption (heating and cooling) On the other hand, Matlab-Simulink demonstrates that the total annual percentage of cooling energy compensation (direct plus storage) difference between the

PV and thermal with storage scenarios does not exceed 1 % in both cases However, differences exist between the two scenarios The performance of daily direct cooling compensation by the PV air-conditioning scenarios is more efficient than in the thermal air-conditioning scenario The direct cooling compensation percentage for the Aswan-TSFH and the Aqaba-TSFH respectively are 39.3 % and 35.8 % for the PV air-conditioning scenarios and 30.8 % and 30.9 % for the thermal air-conditioning scenario The compensation by the storage are 10.7 % and 7.3 %, by the PV air-conditioning with storage scenario and 20.1 % and 11.9 %, by thermal air-conditioning with storage scenario for the two cases respectively

The PV air-conditioning scenario with storage behaves and compensates the cooling demand better than the solar thermal air-conditioning with storage scenario and needs less storage to cover the same amount of cooling load demand However, the storage system in the PV air-conditioning scenario is minor and the direct compensation is major That is vice versa in the thermal air-conditioning scenario This research can be extended to compare and analyze the scenarios in terms of primary energy, economic analysis and different buildings Moreover, the future cost reduction by learning curves

of both technologies can influence the economic feasibility

Contents

Acknowledgements iv

Abstract v

List of Figures ix

List of Tables xii

List of Symbols xiii

List of Abbreviations xvi

1 Introduction 1

1.1 Background 1

1.2 Objectives and Boundary Conditions 2

1.3 Thesis Structure 3

2 Determination of the Reference Building in MENA Regions 4

2.1 Reference Location Climates 4

2.1.1 Meteorological Data for Reference Locations 5

2.2 Reference Building 8

2.2.1 Architecture Design 9

2.2.2 Facade Stricter 10

2.2.2.1 Wall Construction 10

2.2.2.2 Windows 11

2.2.3 Internal Gain 11

2.2.4 Air Change Condition 12

2.2.5 Cooling and Heating Set Points 12

3 Reference Building Thermal Cooling and Heating Load Simulation 13

3.1 TRNSYS Software Simulation Environments 13

3.2 Description of the Simulation 14

3.2.1 Type 56 Mathematical Description 14

3.2.2 TSFH Modeling with Type56 and TRNBuild 16

3.2.3 TSFH Modeling with Type56 and TRNStudio 18

3.3 Thermal Cooling Load Simulation Results and Analysis of Results 21

3.3.1 The Annual Energy Consumption 21

3.3.2 The Performance of Cooling Load 23

4 Solar Air-Conditioning Technologies 26

4.1 Solar Photovoltaic Air-Conditioning Technology 26

4.2 Solar Thermal Air-conditioning Technology 27

5 Solar Air-Conditioning Scenarios Design and Simulation 29

5.1 Matlab-Simulink Simulation Environments 29

5.2 Solar PV Air -Conditioning Scenarios 30

5.2.1 System Components and Design 30

5.2.2 Systems Simulation and Methodology 37

5.2.2.1 PV air-conditioning Without Storage Scenario 38

5.2.2.2 PV Air-conditioning with Storage Scenario 40

5.3 Solar Thermal Air-conditioning Scenario(absorption chiller) 41

5.3.1 System Components and Design 41

5.3.1.1 Solar Thermal Heating System 42

5.3.1.2 Absorption Chiller 47

5.3.3 System Simulation and Methodology 52

6 Simulation Results and Analysis for Solar Air-Conditioning Scenarios 58

6.1 Solar Photovoltaic (PV) Air-conditioning Scenarios 58

6.1.1The Influence of a Direct Cooling production 59

6.1.2 Excess of Cooling Production and External Back-up Cooling for a Battery Design 63

6.1.3 Annual Cooling Energy Compensation Analysis 65

6.1.3.1 PV Air-conditioning Without Storage Scenario 66

6.1.3.2 PV Air-conditioning With Storage Scenario 67

6.2 Results and Analysis for Solar Thermal Air-conditioning Scenario 69

6.2.1 The Influence of Cooling Production 69

6.2.2 Annual Cooling Energy Compensation Analysis 74

6.2.2.1 Excess Cooling Production and External Back-up Cooling Loads 74

6.2.2.2 Annual Cooling Energy Compensation 76

6.2.2.3 Solar Fraction 79

6.3 Thermal Air-conditioning Scenario Versus PV Air-conditioning Scenarios 81

6.3.1 The Direct Cooling Production Load Performance 81

6.3.2 Annual Cooling Compensation Energy Percentage 87

7 Conclusions and Future Research 90

7.1 conclusions 90

7.2 Future Research 94

References 95

Appendices 102

Appendix A: Schematic vapour compression cycle 102

Appendix B: Solar Photovoltaic module data sheet 102

Appendix C : Inverter data sheet, [45] 103

Appendix D:Description of Wet Cooling Tower, [37] 104

Declaration 105

List of Figures

Figure 2.1: Annual distribution of horizontal global solar radiation for Aswan and Aqaba cities, [16], [17] .6 Figure 2.2 Annual distribution of ambient air temperatures for Aqaba and Aswan cities, [16], [17] .6 Figure 2.3:Annual distribution of ambient air relative humidity in Aswan and Aqaba cities, [16], [17] .7 Figure 2.4: sketch of Typical Single Family House(TSFH) in MENA regions plan, [20] .9 Figure 3.1: Zones of TSFH model in TRNBuild 16 Figure 3.2: Aswan-TSFH model (Type 56) with all the required components and

connections in TRNStudio 18 Figure 3.3: Aqaba-TSFH model (Type 56) with all required components and connections

in TRNStudio 19 Figure 3.4: Yearly cooling and heating energy demand for the Aswan-TSFH and Aqaba-TSFH 21 Figure 3.5: Monthly cooling and heating energy demand in (kWh) for the Aswan-TSFH and Aqaba-TSFH 22 Figure 3.6: Yearly Cooling and heating demands distribution(kW) for the Aswan-TSFH 23 Figure 3.7:Yearly Cooling and heating demands distribution in (kW) for the Aqaba-TSFH 24 Figure 3.8: Weakly Cooling load demand distribution in (kW) for the Aqaba-TSFH and Aswan-TSFH 25 Figure 4.1 :Basic structure of PV air-conditioning systems, [2] 26 Figure 4.2 :Basic structure of heat driven and desiccant air-conditioning systems, [2] 27 Figure 5.1: Schematic flow diagram for solar PV air-conditioning without storage 31 Figure 5.2: Schematic flow diagram for solar PV air-conditioning with storage 31 Figure 5.3: The dimensions of a typical single family house (TSFH) - roof area (1) for PV-array installation 34

Figure 5.4: Solar thermal air-conditioning system scenario, coupling of an absorption chiller with a solar heating system 42 Figure 5.5: Schematic diagram for an absorption chiller for chilled water production, [37] 47 Figure 6.1: PV air-conditioning cooling production along the year for Aswan-TSFH 59 Figure 6.2: PV air-conditioning cooling production along the year for Aqaba-TSFH 59 Figure 6.3: Solar-PV air-conditioning cooling production in Summer week for Aswan-TSFH 60 Figure 6.4: Solar-PV air-conditioning cooling production in Summer week for Aqaba-TSFH 61 Figure 6.5: Solar PV air-conditioning cooling production in winter week for Aswan-TSFH 61 Figure 6.6: Solar PV air-conditioning cooling production in winter week for Aqaba-TSFH 61 Figure 6.7: PV air-conditioning without storage scenario, Excess cooling production and external back-up cooling loads for Aswan-TSFH 63 Figure 6.8: PV air-conditioning without storage scenario, Excess cooling production and external back-up cooling loads for Aqaba-TSFH 64 Figure 6.9: yearly cooling energy compensation by the solar PV air-conditioning system with and without storage scenarios for the Aswan-TSFH and Aqaba-TSFH 65 Figure 6.10: Monthly cooling energy compensation by solar PV air-conditioning system with and without storage scenarios for Aswan-TSFH and Aqaba-TSFH 66 Figure 6.11: Solar thermal air-conditioning cooling production along the year for

Aswan-TSFH 69 Figure 6.12: Solar thermal air-conditioning cooling production along the year for Aqaba-TSFH 70 Figure 6.13: Solar thermal air-conditioning cooling production in summer week for Aswan-TSFH 71 Figure 6.14: Solar thermal air-conditioning cooling production in summer week for Aqaba-TSFH 72

Figure 6.15: Solar thermal air-conditioning cooling production in winter week for

Aswan-TSFH 72 Figure 6.16: Solar thermal air-conditioning cooling production in Winter week for

Aqaba-TSFH 72 Figure 6.17: Solar thermal air-conditioning excess cooling production and external back-up cooling loads for Aswan-TSFH 74 Figure 6.18: Solar thermal air-conditioning excess cooling production and external back-up cooling loads for Aswan-TSFH 75 Figure 6.19: The cooling energy compensation by the solar thermal air-conditioning system scenario for Aqaba-TSFH and Aswan-TSFH 76 Figure 6.20: Monthly cooling energy compensation by the solar thermal air-conditioning system scenario for Aswan-TSFH and Aqaba-TSFH 77 Figure 6.21: Annual solar fraction for the solar thermal air-conditioning system scenario

in Aswan-TSFH and Aqaba-TSFH 79 Figure 6.22: Monthly solar fraction for the solar thermal air-conditioning system

scenario in Aswan-TSFH and Aqaba-TSFH 79 Figure 6.23: PV air-conditioning versus solar thermal air-conditioning, cooling

production performance in Summer Week for Aswan-TSFH 81 Figure 6.24: PV air-conditioning versus solar thermal air-conditioning, cooling

production performance in Summer Week for Aqaba-TSFH 82 Figure 6.25:PV air-conditioning versus solar thermal air-conditioning, cooling

production performance in Summer day for Aswan-TSFH 83 Figure 6.26: PV air-conditioning versus solar thermal air-conditioning, cooling

production performance IN Summer day for Aqaba-TSFH 84 Figure 6.27: Percentage of cooling Energy compensation by the three scenarios for Aswan-TSFH 87 Figure 6.28: percentage of cooling Energy compensation by the three scenarios for Aqaba-TSFH 88 Figure A: Schematic vapour compression cycle, [2] 102 Figure D: Schematic drawing of an open type wet cooling tower, [37] 104

List of Tables

Table2.1 :Constructional components of the reference building (TSFH), [21], [20] 10 Table2.2 : Thermal properties of the Single glass window for the reference TSFH in Aswan and Aqaba, TRNSYS library and [13] 11 Table2.3 :Air change(ventilation and infiltration) rate for Aswan-TSFH and Aqaba-TSFH 12 Table 5.1 : Parameters of the flat plate collector, [52] 44 Table5.2: Lithium Bromide-water (WEGRACAL SE 15ACS15) absorption chiller

parameters, compiled from [56] and [10] 50 Table5.3: Technical parameters of the back-up heater, storage and cooling tower, 51 Table6.1: Yearly cooling energy compensation by the solar PV air-conditioning system with and without storage scenarios for Aswan-TSFH and Aqaba-TSFH 66

List of Symbols

Variables Units Description

C1 W/m2K linear heat transfer coefficient

C2 W/m2K2 Quadratic heat transfer coefficient

COPABCH Coefficient of performance for absorption chiller

Cw kJ/kg K Specific heat capacity of water

Wh The back-up cooling energy

Gtilt W/m2 Global solar radiation on a tilted surface

W Heat power production by the absorption chiller

of cooling system

W Compensated cooling power by the storage

K, C Module’s operation temperature

T coll K Average fluid temperature in the collector

∆TS K The temperature difference of the storage tank

U W/m2K Storage heat losses coefficient

- PV module efficiency at the standard test condition

Subscripts

List of Abbreviations

TSFH Typical Single Family House

MENA Middle East and North Africa

NOCT Operation Cell Temperature

TRNSYS TRaNsient SYstem Simulation program

NERC National Energy Research Center

IWES Institute for Wind Energy and Energy System Technology

ETMY Egyptian Typical Meteorological Year

IWEC International Weather for Energy Calculations

1 Introduction

1.1 Background

Worldwide, the growing demand for traditional air-conditioning has caused a

significant increase in demand for primary energy resources ‘‘This results in a

significant increase in peak electric power demand in summer reaching, in many cases,

the capacity limits of the network and causing the risk of blackouts’’ [1] That due to,

increasing living standards, comfort expectations and global warming In many countries of Middle East and North Africa (MENA), air-conditioning is one of the main consumers of electrical energy today For example in Egypt, at least 32 % of the electrical energy used by the domestic sector is for air-conditioning: [2], [3] However, there is a higher solar radiation in the MENA regions, with a potential that is larger than the total electricity demand worldwide The average daily sunlight exceeds 8.8 hours, with an average DNI1 of 2,334 kWh/m2/year [4] Solar air-conditioning is one of the technologies which allows to obtain important energy savings compared to traditional air-conditioning plants, by using the renewable solar source This is definitely the case for the hot and sunny regions in the MENA In addition, the growing demand for air-conditioning in typical single family houses (TSFH) and small office buildings is opening new sectors for this technology in the MENA regions

Today, there are two main solar conditioning technology options: solar thermal conditioning, where the solar absorption cooling is the first type of this option and it is still practical for remote building in places where there is an excess of heat energy available Another option is the solar photovoltaic air-conditioning, by using electricity

air-from renewable sources to power the conventional cooling equipment ‘‘On the other

hand, the market introduction of photovoltaic systems is much more aggressive than that of solar thermal power plants; cost reductions can be expected to be faster for photovoltaic systems But even if there is a 50% cost reduction in photovoltaic systems and no cost reduction at all in solar thermal power plants, electricity production with solar thermal power plants in southern Europe and North Africa remains more cost-

effective than with photovoltaic systems’’ [5]

1 Direct Normal Irradiance

A lot of papers have been published that describe the performance of thermal conditioning technology under different climate conditions in the world: [6], [7], [8] and [9] In addition, there are also a number of publications available that cover the performance of solar photovoltaic air-conditioning technology or different performance between the two technologies such as [10] However, there are very few research on the solar air-conditioning technology under the MENA region climate conditions, for its importance in this region Therefore, there are areas in which one or the other of the two technologies should be preferred for technical reasons under the MENA regions’ climates

air-1.2 Objectives and Boundary Conditions

The performance of solar air-conditioning technology is strongly dependent on the ambient climate conditions, the building standards and the users’ behaviour The main objective of this thesis is to analyze and compare the solar thermal air-conditioning technology and the photovoltaic air-conditioning technology under different thermal load profiles and under the MENA region climate conditions Additionally, to evaluate the cooling compensation by employing this technology to the cooling load demand of the selected building (TSFH) in two different climate locations: Aswan-Egypt, Aqaba-Jordan In order to achieve the aforementioned objectives, the study focuses on the:

 Determination of TSFH as a reference building for the two selected locations in this study : Aswan city in Egypt and Aqaba City in Jordan

 Determination of the TSFH cooling load demand for the two selected locations carried out by the TRNSYS Software

 Design and simulation of three solar air-conditioning scenarios to cover the cooling load demand of a TSFH for the two respective locations where the simulation is carried out by MATLAB-Simulink

The considered scenarios are as following:

 Solar photovoltaic air-conditioning without storage

 Solar photovoltaic air-conditioning with storage

 Solar thermal air-conditioning with storage (absorption chiller)

1.3 Thesis Structure

The climate of the selected location and a detailed description of the reference building are given in chapter 2 The description of the reference building includes its architectural design, orientation, wall construction, window type, indoor climate, air change rate, internal gain, cooling and heating set points

The thermal cooling and heating load demands for the reference building (TSFH) are simulated by TRNSYS software for the two selected locations A description of the simulation environments, the models as well as the simulation results and their analysis are given in Chapter 3 Chapter 4 includes a general description of available solar air-conditioning technologies and its state-of-the-art

In Chapter 5, three solar air-conditioning scenarios have been designed and simulated for each TSFH in the selected locations This chapter discusses three parts: simulation environments, solar radiation on a tilted surface by TRNSYS software and then each of the scenario components and design followed by the scenario simulations and methodology

Chapter 6 includes the simulation results and the analysis for each scenario Then, the comparison between the solar thermal air-conditioning with storage scenario and the two solar PV- air-conditioning scenarios with and without storage is done The conclusions of this study are summarized in chapter 7 Moreover, an outlook for further work that could be done is given

2 Determination of the Reference Building in MENA Regions

To investigate the above objective two cities in two countries were selected from MENA regions, Aqaba city in Jordan from Middle East(ME) and Aswan in Egypt from North Africa(NA) The reference building model in this study was selected for the two locations, namely typical single family house (TSFH) The aim of this chapter is to determine the reference building TSFH, for various climate conditions of the selected locations in MENA regions For the locations climate conditions, solar radiation, ambient air temperature and relative humidity For the building, the construction (i.e wall U-values, type of window glazing), internal heat gains air exchange rate etc were defined That in order to simulate the TSFH thermal load demand by using TRNSYS software The Simulation in more details will be further explained in next chapter

2.1 Reference Location Climates

The building cooling and heating demands are strongly influenced by the outdoor ambient air temperature and global solar radiation around it In this study, the TSFH cooling demand calculations depends on the selected locations climates Aqaba city in Jordan and Aswan city in Egypt

Jordan is located in Middle East (ME) regions its’ area is 9 X 104 km2, 80% of its area is desert The climate of Jordan may be divided into three main categories depending on the altitude: low-, medium- and high-mean temperature regions [11] Aqaba city is located south of Jordan at latitude 29°31'N and longitude 35°E on the Aqaba Gulf of the Red Sea The meteorological station is 51 meters above sea level It is located in the high –mean temperature regions This city is characterized by very hot and dusty weather in summer; summer temperatures rise above 45 ◦C Winter is mild therefore there is little need for heating with extremely little amount of precipitation The mean annual daily average temperature is estimated at around 24.1 ◦C [12], [13]

Egypt is located in North Africa (NA) regions its area 1,001,450 km2 and it is mostly desert Aswan city is the 3rd biggest city in Egypt today and the biggest one in upper Egypt located at latitude 23°54'N and longitude 32°E [14] Aswan enjoys a relatively high temperatures, dry weather and arid climate; Summers in Aswan grow unbearably hot with the average temperature ranging from 31.6 °C to 33 °C and in July sear up to almost 34 °C In Winter the average temperature ranging from 23-30°C and rainfall almost non-existent and no need for heating [15]

2.1.1 Meteorological Data for Reference Locations

The meteorological data for the two reference locations (Aswan, Aqaba) had been selected, these data sets were used to perform the calculations and generate the results presented in this study

The meteorological data file of Aqaba city contains measurement data in 15 minute intervals for the year 2010 It is includes, the horizontal solar radiation (beam, diffuse and global), ambient air temperature and relative humidity The file was received in Excel-format from the National Energy Research Centre (NERC) in Jordan

The meteorological data of Aswan city, in Egyptian Typical Meteorological Year (ETMY) format and in Energy Plus Weather (EPW) format Were received This formats was developed as a standard development for energy simulation by Joe Huang with data provided by the U S National Climatic Data Center whichfor periods of record from 12

to 21 years, all ending in 2003 This file was hourly data included the horizontal solar radiation (beam, diffuse and global), ambient air temperature and relative humidity [16] Figures 2.1 to 2.3 represent the horizontal global irradiation, ambient air temperature and relative humidity data for each location Aqaba and Aswan

Figure 2.1: Annual distribution of horizontal global solar radiation for Aswan and

Aqaba cities, [16], [17]

Figure 2.1 shows, distribution of the global horizontal solar radiation for Aswan city and Aqaba city, in Aswan city has higher peak daily of global horizontal solar radiation than Aqaba city along the year; in summer season reaches near to 1000 W/m2 ,1050 W/m2

and in winter 600 W/m2 , 700 W/m2 for Aqaba and Aswan respectively In addition the radiation difference between the two cities, in winter higher than in summer seasons

Figure 2.2 Annual distribution of ambient air temperatures for Aqaba and Aswan

cities, [16], [17]

Figure2.2 illustrates, the annual distribution of ambient temperatures in Aqaba city and Aswan Approximately in both cities; in summer season the daily maximum peak temperatures reaches to 40oc and in sometimes to 45oc, in winter changes between

25oC to 30oC Aqaba city daily temperatures are fluctuated along the year higher than Aswan, this means Aswan night temperatures higher than Aqaba night temperatures This leads to higher night cooling consumption by the buildings in Aswan city than in Aqaba city

Figure 2.3:Annual distribution of ambient air relative humidity in Aswan and Aqaba

cities, [16], [17]

As shown in Figure2.3,the relative humidity distribute along the year for both cites Aqaba and Aswan Generally Aqaba city has higher ambient air relative humidity along the year than Aswan, especially in July, August and September Additionally, it is fluctuated in Aqaba more than in Aswan The high relative humidity of location, leads to increase building cooling consumption

2.2 Reference Building

The reference building which has been selected in this study is a typical single family house (TSFH) relates to the MENA locations, Aswan city in Egypt and Aqaba city in Jordan This section defines the TSFH and the definition include architecture design and orientation, constriction building elements descriptions (walls, roof, floor and windows), internal heat gain, the heating and cooling set points and the air change conditions This building data must be determined in order to simulate the thermal cooling and heating demands for the building by using TRNSYS software.More details about the thermal consumption simulation by TRNSYS software for TSFH will be further explained in next chapter

According to department of statistic (DOS), type of building (TSFH) called ‘’Dar’’ in Jordan represents about 72 % of the total residential building in Jordan [18], [19] As mentioned by [11], 54.6 % of the dwellings in Jordan are detached as TSFH In addition the average useful living floor area per capita is about 20m2 and 6 persons residents per dwelling Hollow cement-blocks are most widely used for constructing walls: nearly two-thirds of the total housing being built with such cheap blocks, followed by reinforced concrete and white-stone Nearly 95% of flat roofs, in Jordan are constructed using reinforced concrete, and the remaining fraction employed roof tiling, asbestos and/or corrugated steel-sheets

Most of TSFH in MENA regions specially in Jordan and Egypt, has same building architecture design, it has a flat roof, it consists Gust room , living room, kitchen, two or three bedrooms and the bathrooms

However a simplification was made in this study, the typical Single family house in Jordan same that’s in Egypt In order to simplify the comparison of solar thermal air-conditioning scenarios and solar photovoltaic air-conditioning scenarios, which as the major objective in this study, Figure 2.4 shows the TSFH sketch and It can be described

as follows [20], [13]:

2.2.1 Architecture Design

The reference object (of TSFH) was taken from [20], [13] (see Figure 2.4) The floor area

is about 224 m2, perimeter is 60.35 m and ceiling internal height is 2.86 m It is rectangular shape and consists of three bedrooms, living room, guest room and Kitchen Number of occupants is 6 persons

The sketch of TSFH in Figure 2.4 shows the building orientation where the Gust room and the living room are facing to south The zones dimensions were provided by Eng Tawfiq Al- Khamayseh (Architecture engineer works for Al-Bayader Company for construction and engineering in Ramallah, Palestine) This architecture design of the TSFH was considered for the two climate locations, Aswan and Aqaba cites

Figure 2.4: Sketch of Typical Single Family House(TSFH) in MENA regions plan, [20]

2.2.2 Facade Stricter

2.2.2.1 Wall Construction

The construction consists of typical stone walls(External walls), it consists of stone, concrete, concrete blocks and plaster The various material of the building envelope, layers the thicknesses and energy performance data describing the reference building

(TSFH) listed in Table 2.1 [21], [20]

Table2.1 : Constructional components of the reference building (TSFH), [21], [20]

[m]

Density [kg/m3]

Thermal Conductivity [kJ/h m K]

Specific heat capacity [kJ/kg K]

U-Value of component [W/m2K]

6.12

1.008 0.864 0.936

2000

1400

2000

4.32 2.7 4.32

1.008 0.864 1.008

1400

2300

1200

3.42 6.3

0.612

1.008 0.936

1.69

1.0 0.864 0.864 0.936

1.0

1.18581

2.2.2.2 Windows

A single glazed window with U-value of 5.68 W/m2 Ok was selected for the reference

building TSFH ‘‘This considered as one of the most popular windows type in the

selected locations The U-value indicates the rate of heat flow due to conduction, convection, and radiation through a window as a result of a temperature difference between the inside and outside in (W/m2.K)’’ [13] The windows parameter are

summarized in Table 2.2 This parameters According to TRNSYS library and [13]

According to [13], the optimum window area for the TSFH in Aqaba city, on the east and

on west facades amounts to 20% of the wall surface area On the North facade, windows area is 10% whereas 30% for the west facade Same for Aswan-TSFH was assumed The TSFH windows were considered without any internal or external shading

Table2.2 : Thermal properties of the Single glass window for the reference TSFH in Aswan and Aqaba, TRNSYS library and [13]

Internal gain is thermal (sensible or latent) heat which dissipates from persons, lighting,

or electric equipments (computer, wash machine, etc.) This heat gains contributes in the building cooling and heating load demands The rate of internal heat gain is 150 W from occupants and electric equipment It is considered based on ISO 7730 standard where the number of occupants is 6 persons in TSFH The heat gain 120 W/person (Seated, very light writing) was considered constant, which represents an average activity could be done daily by the occupants in addition the heat gain from appliance defined also as a constant (300 W/day) during the year that according to ISO 7730 standard in TRNSYS data library

2.2.4 Air Change Condition

The air tightness of Middle East and South East Asia buildings is less than European standard, which leads to higher infiltration rate According to the United Arab Emirates UAE building regulations, the ventilation rate should be 0.4/h

In this study, the TSFH for both locations Aswan and Aqaba have the same ventilation and infiltration rates Natural ventilation was considered for this building according to MASDAR energy design guide line [22]as it regarded a proper code for efficient building design where the natural ventilation is constant during the day and throughout the year The value of infiltration rate has been defined according to ASHRAE 90.1 standard [23] The Iinfiltration and ventilation rats for TSFH are given in Table2.3

Table2.3 : Air change (ventilation and infiltration) rate for Aswan-TSFH and

Aqaba-TSFH

2.2.5 Cooling and Heating Set Points

The initial step in the cooling and heating load consumption calculation is defending indoor and outdoor conditions of TSFH Indoor conditions depends on building use, number and type of occupancy, and/or code requirements In this study, the TSFH indoor design conditions, the set-point temperature and relative humidity for cooling and heating are set according to ASHRAE, Handbook Fundamental (2005) [24], [20] For cooling, it is 24 ◦C dry bulb and a maximum of 50–65% relative humidity For heating, it

is 20 ◦C dry bulb and 30% relative humidity

3 Reference Building Thermal Cooling and Heating Load Simulation

The major objective for this chapter is to calculate the thermal cooling and heating loads for the two cases: Aswan-TSFH and Aqaba-TSFH cases That is in order to investigate the main objective of this study: to compare and to analyze the solar thermal air-conditioning technology and PV air-conditioning technology in the MENA regions This chapter has two parts The first part discusses and describes the thermal cooling and heating loads simulation by using TRANSYS Software The second part includes the thermal cooling load simulation results and analysis of the results

3.1 TRNSYS Software Simulation Environments

TRANSYS is a transient system simulation program It is a well known software diffusely adopted for both commercial and academic purposes The software includes a large

library of built-in components, often validated by experimental data [8], [25] It is a

component-based simulation engine Components (or types) are individual engineering systems such as a boiler, thermal storage tank, PV panels, or a pipe that are defined by a discrete set of inputs, outputs, parameters, and the mathematical functions which govern their operation It is dynamic, transient building energy and energy supply systems modelling tool which offers distinct advantages as well as disadvantages over its alternatives (e.g energy plus) [26] It is a complete and extensible simulation environment for the transient simulation of systems, including multi-zone buildings [20]

The program allows the users to create and design complex energy engineering systems

by adding and dropping components from the software library to a simulation map and connects this components’ inputs and outputs together [26] This makes TRANSYS a very capable tool to simulate the building cooling and heating loads For the sake of the aforesaid reasons, the TRANSYS software is selected in this study to simulate TSFH cooling and heating loads for each case: Aswan-TSFH and Aqaba-TSFH TRNSYS consists

of suitable of programs In this study, only two of these programs have been deployed: TRNSYS simulation studio and Multi-zone building (TRNBuild) [27]

3.2 Description of the Simulation

The first step before starting this simulation, which is done in Chapter 2, includes: the

selecting TSFH-indoor design conditions ( such as, number of occupancy, internal gains,

air change conditions ,heating and cooling set points etc ), selecting TSFH-envelope

data ( e.g architectural design, facade stricter data etc ) and selecting TSFH-outdoor

climatic data (solar radiation, ambient temperature, relative humidity)

TYPE 56 (Multi-zone building model) in TRNSYS is chosen to simulate the heat

conduction through opaque surfaces of the TSFH-envelop In order to use this type, two

separate processing program must be carried out The first process, TRNBuild program

reads in and processes a file containing the TSFH description and generate two files

(described later) The second process occurred in the TRNStudio program, the two

generated files will be used by the TYPE 56 component during a TRNSYS simulation

3.2.1 Type 56 Mathematical Description

The TRNSYS mathematical model calculations are influenced by the outdoor climatic

conditions, the indoor design conditions and the TSFH envelop structure ‘‘The heat

balance method is used by TRNSYS as a base for all calculations For conductive heat

gain at the surface on each wall, TRNSYS use Transfer Function Method (TFM) as a

simplification of the arduous heat balance method’’ [28], [29]:

-

- ……….… … ………… ………… … …(3.1)

(3.2)

‘‘ Where the surface temperatures and heat fluxes are evaluated at equal time intervals

The k refers to the term in the time series, and it specified by the user within the

TRNBUILD description within the TRNBUILD program the coefficients of the time

-

series (a's, b's, c's, and d's) are determined by the z-transfer function routines of

literature ’’[30] The Heat gain by radiation and convection is calculated using [28]:

……… ……….… (3.9)

For more details about the mathematical model which are used by TRNSYS simulation, see TRNSYS16 manual [33]

3.2.2 TSFH Modeling with Type56 and TRNBuild

TRNBuild is used to enter the TSFH input data and to create the TSFH description file (*.bui) This file includes all the information required to simulate the building where (*.bui) file used to generate three new files: the (*.bld)2, (*trn)3 files which are used by TYPE 56 during the simulation process in TRNStudio program and information file(*.inf)4)

As shown in Figure 3.1, TRNBuild allows the users to specify all the building structure in details that is needed to simulate the thermal behaviour of the TSFH such as geometry data, wall construction data, windows data, etc Furthermore, it needs SCHEDUALE information which define the internal heat gain from the equipment and occupants during the day in the TSFH

Figure 3.1: Zones of TSFH model in TRNBuild

2 The file containing the Geometric information about the building

3 The file containing the wall transfer function coefficients

4 An informational file

This section includes a brief description of steps for the TSFH modelling with TYPE 56 and TRNBuild which are followed in this study

As shown in Figure 3.1, the TRNBuild manager defines the project details: TSFH orientation, iconic properties which define the parameter value for software calculation such as air density, specific heat of air etc Inputs icon which is used to add the required INPUTS to TYPE 56 (such as, control strategies etc.) whereas the outputs icon describe the OUPUTS of TYPE 56 such as sensible energy demand of zone etc where this is the last step of the building description

The TSFH zones thermal definition step include the adding zone walls and windows in addition to its thermal description (see Tables 2.1 and 2.2): defining the materials that will make up the layers of the wall (from internal zone to external) in addition to the wall area, geography (external and internal), thermal conductivity etc., defining the materials that will make up the layers of the window and adding (its thermal properties, area and orientations etc.)

After the TSFH zones definition step, inserting the TSFH zones required regime, data step has been followed which includes: infiltration and ventilation data, heating and cooling set points, internal gain setting data, comfort and Humidity In this study ,Chapter 2 includes all of the required data for the second step where the infiltration and ventilation data listed in Table2.3, the internal gain is considered based on ISO 7730 standard Cooling set point is 24 0C dry bulb and a maximum of 50–65 % relative humidity The Heating set point is 20 0C dry bulb and 30 % relative humidity

Defining the outputs needed from TYPE 56, in this step the output can be selected from the list such as, sensible energy demand (cooling and heating) of building, air temperature of zone, etc In this study, the sensible energy demand of three bedrooms, living room, guest room and kitchen is defined as outputs for TYPE 56

The final step in the running model is to generate the TYPE 56 files: (*.bui) file used to generate three new files: the (*.bld)5, (*trn)6 files which are used by TYPE 56 during the simulation process in TRNStudio program and information file (*.inf)7

5 The file containing the Geometric information about the building

6 The file containing the wall transfer function coefficients

3.2.3 TSFH Modeling with Type56 and TRNStudio

After the TSFH Model in TRNBuild is created and the TSFH description file (*.bui) is generated, the TSFH modelling with Type56 and TRNStudio started to complete the simulation of the TSFH thermal cooling and heating loads demands The brief description of the simulation steps which are followed in this software (TRNStudio) are

as described as follows:

The first step, creating a new Multizone building project and all its necessary parameters have been entered (such as drawing TSFH plan, setting zone properties, setting window, etc) Once the created project has been finished the simulation studio will create a multi zone building description (stored in a BUI file), translate the TSFH description file (*.bui) file to the internal files necessary for simulation (*.bld8, *trn9

files) from TRNBuild program, create a simulation project (stored in a TMF file) and open it in the simulation studio [33] So a simulation with the important components and links for the first run are automatically generated

Figure 3.2: Aswan-TSFH model (Type 56) with all the required components and

connections in TRNStudio

7 An informational file

8 The file containing the Geometric information about the building

9 The file containing the wall transfer function coefficients

Figure 3.3: Aqaba-TSFH model (Type 56) with all required components and

connections in TRNStudio

Figure 3.2 and Figure 3.3 show that the TSFH model (Type 56) with all required components and connections in simulation studio for Aswan and Aqaba respectively The studio simulation has been started to specify the values for the variables in the components of the TSFH model then determines how data flows from one component to another (such as solar radiation data flows from TYPE 16e to TYPE 56 ) This data flow

is indicated by a link between two components in the Assembly Panel window Assembly Panel window includes the simulation components as shown in the right hand side in Figure 3.2 and Figure 3.3 However, the link shown on the assembly panel is purely informational So it must specify the details of the link between two components

to actually flow data from one component to another [33]

As known in Chapter 2, the meteorological data of Aswan city in TMY and EPW format and its hourly horizontal solar radiation data In addition, regarding the TSFH geometry, the direct and diffuse radiation of every hour should be determined Then it must be converted into hourly tilted radiations depending on the sun position in the sky and on the TSFH surface’s slope from the horizontal plan So TYPE 15-3, weather data reading and processing have been chosen for the Aswan-TSFH model in order to read the Aswan

meteorological data file and to calculate the hourly solar radiation (direct plus diffuse) regarding to the TSFH surface’s slope and on the sun position in the sky After that data has been processed, it will be provided from TYPE 15-3 to TYPE 56 in order to simulate the TSFH cooling and heating demands.

In the simulation case of Aqaba-TSFH, there is a difference because the metrological data file has been in Excel format So the TYPE 9e has been chosen in order to call and read the excel data file which provides this data through the link to TYPE 16e The TYPE 16e completes the data processing before delivering it to TYPE 56 as in Aswan-TSFH case In this step, the Reindl model has been chosen in TYPE 15-3 and TYPE 16e in order

to calculate the tilted solar radiation For more details about Reindl mathematical

model, see the TRNSYS16 module [33]

As shown in the above figures, TYPE 33e has been chosen for both cases ‘‘This

component takes as input the dry bulb temperature and relative humidity of moist air from the processing data component and calls the TRNSYS Psychrometrics routine, returning the following corresponding moist air properties: dry bulb temperature, dew point temperature, wet bulb temperature, relative humidity, absolute humidity ratio,

and enthalpy’’ [33] This data is transferred to TYPE 56 to use it in the cooling and

heating demand calculations

TYPE 69b is selected for each model in order to determine the effective sky temperature, which is used by TYPE 56 to calculate the long-wave radiation exchange between an arbitrary external surface of the TSFH and the atmosphere TYPE 65 is online graphics component which is used to display selected system variables while the simulation is progressing [33]

Final step in the TRNStudio simulation is the running step, where the cooling load is calculated in 15 minutes time step by TRNSYS software for the two case studies Then the cooling and heating load demand simulation results for the TSFH has been provided for both cases

3.3 Thermal Cooling Load Simulation Results and Analysis of Results

As mentioned before, the major objective of this simulation is to determine the cooling load of a typical single family house in two different climate locations in the MENA regions: Aswan city in Egypt and Aqaba city in Jordan The discussion and analysis on simulation results concentrate mainly on sensible cooling load demand of TSFH (three bedrooms, living room, guest room and Kitchen) The simulation results and the analysis of the results are documented in subsequent subsections

3.3.1 The Annual Energy Consumption

This section discusses the annual cooling load consumption for both cases, Aswan-TSFH and Aqaba-TSFH Figure 3.4 and Figure 3.5 below diagram the total annual and monthly cooling and heating energy consumptions for the aforementioned cases respectively

Figure 3.4: Yearly cooling and heating energy demand for the Aswan-TSFH and

Aqaba-TSFH

The simulation result in Figure 3.4 shows the annual energy consumption where the total cooling load energy are : 44,330 kWh/year and 43,490 kWh/year; the total heating load energy are: 1114 kWh/year and 1635 kWh/year for the Aswan-TSFH and the Aqaba-TSFH cases respectively On the other hand, 97.5 % and 96.3 % of the annual energy consumption are cooling load for the two cases respectively

Figure 3.5: Monthly cooling and heating energy demand in (kWh) for the

Aswan-TSFH and Aqaba-Aswan-TSFH

Figure 3.5 shows the cooling energy required during a long period throughout the year which is ten months, from February to the end of November, while the heating energy period is very short, three months (January, February and December) for both cases The previous results and discussion show the extent of a need and importance of cooling compared to heating for both cases in the aforementioned locations

The monthly cooling energy demand in Aswan-TSFH is higher than Aqaba–TSFH’s throughout the year except for the months of June, July and August Whereas, in Aqaba-TSFH, there is a higher cooling energy consumption due to a higher humidity in Aqaba city than in Aswan city as shown in Figure 2.3 for the reason that the ventilation increases the inside building’s humidity and hence it causes the mentioned difference

3.3.2 The Performance of Cooling Load

Now this section is dealing with the TSFH cooling power demand(real-time power kW), not energy yields (kWh) Because this study going to compensate the power production from the solar air-conditioning systems, not energy Production However, Figure 3.6 and Figure 3.7 display the cooling load demand distribution throughout the year, for Aswan-TSFH and Aqaba-TSFH cases These loads follow the solar radiation load which was shown in Figure 2.1 In addition, it follows the outdoor ambient air temperature distribution throughout the year Furthermore it follows the outdoor ambient air relative humidity, where high relative humidity leads to increasing the cooling demands So it will be worth to compensate the solar irradiation to this cooling consumption

The maximum cooling load for Aswan-TSFH is 13.9 kW as viewed in Figure 3.6 As shown in the Figure, the peak load takes place during the months of June and August On the other hand, the smallest cooling load occurs during January, February and December For Aqaba-TSFH, the simulation result diagrammed in Figure 3.7 shows that the maximum cooling load is in the range 14.8 -15.3 kW and this load occurs during the periods of June and August Besides, the smallest cooling load happens during January and December

Figure 3.6: Yearly Cooling and heating demands distribution(kW) for the

Aswan-TSFH

Figure 3.7: Yearly Cooling and heating demands distribution in (kW) for the

Aqaba-TSFH

The cooling demand generally follows the outside ambient air temperature Normally, higher temperature leads to higher cooling load due to a heat transition through the building’s envelope from hotter outside to a cooler inside of the building In Aqaba city, the outside average monthly ambient temperature varies from around 15 0C in January

to almost 35 0C in August In addition, there are bigger daily ambient temperature fluctuations compared with Aswan’s ambient air temperature (see Figure 2.2) which in turn leads to a variation in cooling load throughout the year In Aqaba-TSFH, as shown

in Figure 3.7, the highest cooling load occurs between June and August , which matches the highest outside ambient temperature

In comparison with Aqaba city, the ambient temperature in Aswan city does not vary a lot throughout the year The minimum monthly ambient temperature is 20 0Cin January and the maximum is 350C in August In addition, it has low daily fluctuations (see Figure 2.2) A small variation in ambient temperature leads to a minor variation in the cooling load demand in Aswan-TSFH (see Figure 3.6) The lower cooling load fluctuation of Aswan-TSFH means higher night cooling load demand, compared with Aqaba-TSFH According to Figure 3.5; during the months of June, July and August; the cooling energy consumption in Aqaba-TSFH is higher than Aswan-TSFH’s Hence, identical results are