Title Page
Abstract
Contents
Nomenclature 18
Chapter 1. Introduction 26
1.1. Background 26
1.2. Literature review 30
1.2.1. Experimental and simulation study on SGSHPs with serial and parallel configurations 30
1.2.2. Optimization of SGSHPs with serial and parallel configurations 34
1.3. Objectives 38
Chapter 2. Method 41
2.1. Experiment 41
2.1.1. Experimental setup and test procedure 41
2.1.2. Measuring devices 48
2.1.3. Data reduction 53
2.2. TRNSYS Simulation 54
2.2.1. System description 54
2.2.2. Simulation conditions and model 58
2.3. Optimization of SGSHPs with serial and parallel configurations 69
2.3.1. Optimization conditions and design parameters 69
2.3.2. Optimization process 74
2.3.3. LCCP and LCC analysis 81
Chapter 3. Performance characteristics of SGSHPs with serial and parallel configurations 87
3.1. Introduction 87
3.2. Results and discussion 89
3.2.1. Operating characteristics of HGSHPs with serial and parallel configurations 89
3.2.2. Performance comparison of HGSHPs with serial and parallel configurations 95
3.2.3. Performance comparison of SGSHPs with serial and parallel configurations in long-term operation 109
3.3. Summary 131
Chapter 4. Optimization of SGSHPs with serial and parallel configurations 135
4.1. Introduction 135
4.2. Results and discussion 136
4.2.1. Breakdown of LCC and LCCP 136
4.2.2. Optimization results 139
4.2.3. Effects of the initial conditions on the optimization of the SGSHPs 166
4.3. Summary 176
Chapter 5. Concluding remarks 181
5.1. Conclusions 181
5.2. Future works 187
References 188
Appendix A. Uncertainty analysis 198
Table 1.1. Literature review on SGSHPs with serial and parallel configurations. 33
Table 1.2. Literature review on optimization of SGSHPs with serial and parallel configurations. 37
Table 2.1. Specifications of components of experimental setup. 46
Table 2.2. Test conditions for SGSHPs with serial and parallel configurations. 47
Table 2.3. Specifications of RTD sensor. 48
Table 2.4. Specifications of pressure transmitter. 49
Table 2.5. Specifications of mass flow meter. 50
Table 2.6. Specifications of volumetric flow meter. 50
Table 2.7. Specifications of electric power meter. 51
Table 2.8. Specifications of data acquisition unit. 52
Table 2.9. Thermal transmittance of building and heating and cooling demands for 20 years. 63
Table 2.10. Parameters used for building simulation model. 64
Table 2.11. Parameters used for solar collector model. 65
Table 2.12. Parameters used for ground heat exchanger model. 66
Table 2.13. Parameters used for storage tank model. 67
Table 2.14. Parameters used for circulation pump model. 68
Table 2.15. Thermodynamic properties of the selected refrigerants. 72
Table 2.16. Optimization conditions and design parameters. 73
Table 2.17. Parameters used for ANN and MOGA. 80
Table 2.18. Parameters used for LCCP analysis. 83
Table 2.19. Parameters used for LCC analysis. 86
Table 4.1. Optimal design parameters and refrigerant. 165
Table A.1. Uncertainties of parameters for experiment. 199
Fig. 1.1. SGSHPs with (a) serial and (b) parallel configurations. 29
Fig. 1.2. Number of studies on SGSHPs with serial and parallel configurations. 32
Fig. 1.3. Number of studies on optimization of SGSHPs with serial and parallel configurations. 36
Fig. 2.1. Experimental setup to investigate HGSHPs with serial and parallel configurations. 44
Fig. 2.2. Schematic of experimental setup to investigate HGSHPs with serial and parallel configurations. 45
Fig. 2.3. Schematics of (a) GSHP system and SGSHP systems with (b) serial and (c) parallel configurations. 56
Fig. 2.4. Operation modes for SGSHP systems with (b) serial and (c) parallel configurations. 57
Fig. 2.5. (a) Temperature bins and (b) monthly total horizontal solar radiation for the selected regions. 61
Fig. 2.6. DHW consumption profiles according to hours. 62
Fig. 2.7. Performance of SGSHPs with serial and parallel configurations using R134a and alternative refrigerants. 71
Fig. 2.8. Optimization process for SGSHPs with serial and parallel configurations. 78
Fig. 2.9. Schematic of a trained ANN network to predict the LCC and LCCP. 79
Fig. 3.1. Pressure and enthalpy diagram of HGSHP system with a serial configuration in (a) serial and (b) forced recovery modes. 92
Fig. 3.2. Pressure and enthalpy diagram of HGSHP system with a parallel configuration in (a) parallel and (b) natural recovery modes. 93
Fig. 3.3. Pressure and enthalpy diagram of LSHP and HGSHP systems with serial and parallel configurations. 94
Fig. 3.4. Mass flow rate of refrigerant of the HGSHPs under serial and parallel modes according to Tw.i.HSHX and. Vw.HS.[이미지참조] 102
Fig. 3.5. (a) Heating capacity and (b) total work input of the HGSHPs under serial and parallel modes according to Tw.i.HSHX and. Vw.HS.[이미지참조] 103
Fig. 3.6. COP of the HGSHPs under serial and parallel modes according to Tw.i.HSHX and.Vw.HS.[이미지참조] 104
Fig. 3.7. HELS and HERLS of the HGSHPs under serial and parallel modes according to Tw.i.HSHX and Vw.HS.[이미지참조] 106
Fig. 3.8. (a) Heating capacity and COP and (b) HEHS and HELS of the HGSHPs under natural and forced recovery modes according to Tw.i.HSHX.[이미지참조] 107
Fig. 3.9. (a) Refrigerant mass flow rate and total work input and (b) heating capacity and COP of serial and parallel modes according to Tw.o.LS.[이미지참조] 108
Fig. 3.10. Operation time of SGSHPs with serial and parallel configurations in (a and b) Berlin, (c and d) Helsinki, (e and f) Stockholm, and (g and h) Seoul. 119
Fig. 3.11. Heat recharged into and extracted from the ground of SGSHPs with serial and parallel configurations. 121
Fig. 3.12. Variation in the ground temperatures of GSHP and SGSHPs in (a) Berlin, (b) Helsinki, (c) Stockholm, and (d) Seoul. 123
Fig. 3.13. Variation in the COP of GSHP and SGSHPs in (a) Berlin, (b) Helsinki, (c) Stockholm, and (d) Seoul. 125
Fig. 3.14. Variation in the boiler power consumption of GSHP and SGSHPs in (a) Berlin, (b) Helsinki, (c) Stockholm, and (d) Seoul. 127
Fig. 3.15. Total energy consumption of GSHP and SGSHPs over 20 years in (a) Berlin, (b) Helsinki, (c) Stockholm, and (d) Seoul. 129
Fig. 3.16. Solar collector efficiency according to (a) month in Berlin and (b) solar collector area in the regions. 130
Fig. 4.1. Breakdown of the (a) LCC and (b) LCCP of the SGSHPs with the serial and parallel configurations. 138
Fig. 4.2. LCC and LCCP of SGSHPs with the serial and parallel configurations according to the ASC and LGHX in (a) Berlin, (b) Helsinki, (c) Stockholm, and (d) Seoul.[이미지참조] 149
Fig. 4.3. Pareto fronts of SGSHPs with serial and parallel configurations according to refrigerants. 153
Fig. 4.4. LCCP and LCC for the optimized SGSHPs with serial and parallel configurations according to refrigerants. 157
Fig. 4.5. Optimal design parameters for the SGSHPs with the serial and parallel configurations. 158
Fig. 4.6. LCC and LCCP reductions of SGSHPs with serial and parallel configurations in (a) Berlin, (b) Helsinki, (c) Stockholm, and (d) Seoul. 160
Fig. 4.7. (a) LCC and (b) LCCP reductions of SGSHPs compared to the GSHP according to design parameters. 161
Fig. 4.8. Performance improvement of the SGSHPs compared to the GSHP in (a) Berlin, (b) Helsinki, (c) Stockholm, and (d) Seoul. 163
Fig. 4.9. (a) LCH and (b) LCEH of the GSHP and optimized SGSHPs in the regions. 164
Fig. 4.10. LCC and LCCP for the GSHP and optimized SGSHPs with serial and parallel configurations according to the building insulation. 171
Fig. 4.11. LCC and LCCP for the GSHP and optimized SGSHPs with serial and parallel configurations according to the reduction in Gelec.[이미지참조] 173
Fig. 4.12. LCC and LCCP for the GSHP and optimized SGSHPs with serial and parallel configurations according to the increase in Celec.[이미지참조] 175