Solar cooling systems can be a cost-effective and environmentally attractive air-conditioning solution. The design of such systems, however, is complex. Research carried out under the aegis of the International Energy Agency's Solar Heating and Cooling Program has shown that there is a range of seemingly subtle design decisions that can impact significantly on the performance of solar cooling systems. In order to reduce the risk of errors in the design process, this guide provides detailed and very specific engineering design information. It focuses on case study examples of installed plants that have been monitored and evaluated over the last decade. For three successful plants the design process is described in detail and the rationale for each key design decision is explained. Numerical constraints are suggested for the sizing / selection parameters of key equipment items. Moreover, the application conditions under which the system selection is appropriate are discussed. By following The Guide for any of the three specific solar cooling systems, the designer can expect to reliably achieve a robust, energy-saving solution. This book is intended as a companion to the IEA Solar Cooling Handbook which provides a general overview of the various technologies as well as comprehensive advice to enable engineers to design their own solar cooling system from first principles.
About the Editors xi
List of Contributors xiii
The IEA Solar Heating and Cooling Programme xv
Notes from the Editors xvii
Foreword xix
1 Introduction 1
1.1 About the IEA SHC Task 48 2
1.2 Ambition and philosophy of the book 3
References 4
2 General considerations 5
2.1 Solar thermal air-conditioning general flowsheet 5
2.2 Key design principles 7
2.3 General economic considerations 13
2.4 Performance assessment of SHC systems 16
References 18
3 Case study of a solar cooling system with a small NH3 /H2 O absorption chiller 19
3.1 Application description and design philosophy 19
3.1.1 Background 19
3.1.2 Rationale for the selected configuration 19
3.2 Solar heating and cooling process description 21
3.2.1 Flowsheet description 21
3.2.2 Control philosophy 22
3.2.2.1 Heating and cooling mode selection 23
3.2.2.2 Solar and water-heating flow loops 24
3.2.2.3 Backup heating flow loop 26
3.2.2.4 Chiller process flow loop 28
3.3 Equipment specification 29
3.3.1 Absorption chiller 30
3.3.2 Solar collector field 31
3.3.3 Solar heat exchanger 34
3.3.4 Thermal storage tank 34
3.3.5 Cooling tower 36
3.3.6 Pumps and hydraulics 36
3.4 Hazard and operability 37
3.4.1 Hazard management 37
3.4.2 Commissioning/initial startup 38
3.4.3 Overall performance monitoring 40
3.5 Case study system performance 41
3.5.1 Monthly energy flows 41
3.5.1.1 Source of heat 41
3.5.1.2 Cooling performance 41
3.5.1.3 Heating performance 45
3.5.1.4 Combined heating and cooling performance 46
3.5.2 Instantaneous and daily energy flows 47
3.6 Modeling performance analysis 51
3.6.1 TRNSYS component simulation methodology 51
3.6.2 Case study simulation scenarios 52
3.6.3 Results 52
3.6.3.1 Cold production (QSS.HP) 57
3.6.3.2 Seasonal performance factor (SPFel.thC) 57
3.7 Indicative commercial analysis 58
3.8 Quality assurance checklist 61
3.8.1 Lessons learned 61
3.8.2 Evaluation against principles 62
References 64
4 Case study of a solar cooling system combining an absorption chiller with domestic hot water production 67
4.1 Application description and design philosophy 67
4.1.1 Background 67
4.1.2 Rationale for the selected configuration 68
4.2 Solar cooling process description and design philosophy 69
4.2.1 Flowsheet description 69
4.2.2 Control Philosophy 71
4.2.2.1 Cooling/hot water mode selection 71
4.2.2.2 Control of solar primary circuit pump (Pump 1) 72
4.2.2.3 Control of the solar secondary circuit pump (Pump 2) 72
4.2.2.4 Control of the absorption chiller (pumps 3, 4 and 5, cooler fan) 72
4.2.2.5 Control of the domestic hot water heating pumps (pumps 6 and 7) 73
4.3 Equipment specifications 73
4.3.1 Absorption chiller 73
4.3.2 Solar collector field 75
4.3.3 Evaporatively-cooled dry cooler 77
4.3.4 Thermal storage tank 78
4.3.5 Drain-back tank 79
4.3.6 Pumps 79
4.4 Hazard, operability and installation experiences 80
4.4.1 Hazard management 80
4.4.2 Installation experiences 80
4.4.2.1 Architectural issues 82
4.4.2.2 Installer skills 82
4.4.2.3 Use of the stairwell 82
4.4.2.4 Installation in an occupied building 82
4.4.2.5 Evaporator circuit connection to the main chilled water circuit 82
4.4.3 Commissioning/initial startup 83
4.4.4 Overall performance monitoring 83
4.5 Case study system performance 83
4.5.1 Monthly energy flows 83
4.5.1.1 Source of heat 85
4.5.1.2 Cooling and heating performance 85
4.5.2 Daily energy flows 86
4.6 Modeling performance analysis 87
4.6.1 TRNSYS component simulation methodology 87
4.6.2 Results 87
4.6.2.1 Solar collector tilt angle scenario analysis 90
4.7 Indicative commercial analysis 91
4.7.1 Actual project 91
4.7.1.1 Capital investment cost 91
4.7.1.2 Annual operating and maintenance costs 92
4.7.2 Greenfield sites (IEA Task 48 methodology) 94
4.8 Quality assurance checklist 94
4.8.1 Lessons learned 94
4.8.2 Evaluation against principles 95
References 97
5 Design guide for solar cooling with double-effect absorption chillers 99
5.1 Application description and design philosophy 99
5.1.1 Background 99
5.1.2 Rationale for the selected configuration 100
5.1.2.1 Solar collector field selection/sizing 101
5.1.2.2 Backup heat source 102
5.1.2.3 Hydraulics 102
5.2 Solar cooling process description 104
5.2.1 Flowsheet description 104
5.2.2 Control philosophy 105
5.2.2.1 Solar flow loop 105
5.2.2.2 Chiller process flow loop 106
5.2.2.3 Cooling water flow loop 108
5.3 Equipment specification 108
5.3.1 Absorption chiller 110
5.3.2 Solar collector field 110
5.3.3 Thermal storage tank 112
5.3.4 Pumps 113
5.4 Hazard and operability 114
5.4.1 Hazard management 114
5.4.2 Commissioning/initial startup 115
5.5 Case study system performance 117
5.6 Design performance analysis 120
5.6.1 TRNSYS component simulation methodology 120
5.6.2 Case study simulation scenarios 122
5.6.3 Results 122
5.6.3.1 Storage tank sizing, Sydney location 122
5.6.3.2 Impact of climate 124
5.7 Indicative commercial analysis 126
5.8 Quality assurance checklist 133
5.8.1 Lessons learned 133
5.8.2 Evaluation against principles 134
References 137
Index 139
