Investigating the Suitability of use of low GWP Working Fluid in small-sized Air Source Heat Pumps using MATLAB/SIMULINK (Thesis Sample)

Investigating the Suitability of use of low GWP Working Fluid in small-sized Air Source Heat Pumps using MATLAB/SIMULINK. Abstract Global warming is a major environmental concern, which significantly impacts ecological systems and the safety of coastal cities, therefore effective methods must be adopted to reduce the greenhouse gas emissions and the consumption of fossil fuels. The project discoured herein investigated the suitability of use of the low Global Warming Potential (GWP) working fluids in small-sized heatpumps by use of the analytical and parametric models, simulation and analysis of the effect of the volumetric heating/cooling capacity of the working fluid on the Coefficient of Performance (COP) of the air source heat pump models using MATLAB/SIMULINK. The experimental results that were obtained from the simulations showed a direct proportional relationship between the volumetric heating/cooling capacity of the working fluid and the Coefficient of Performance (COP) of the heatpump. However, much research has examined the performance, characteristics, and application potential of low-GWP refrigerants in heat pumps. A maximum volumetric heating/cooling capacity of the working fliud, of approximately 150W corresponded to the maximum Coefficient of Performance (COP) of the heatpump, of around 5.4 given a maximum enthalpy change of 400kJ/kg in the condenser or evaporator in the heating mode or cooling mode respectively. The Coefficient of Performance (COP) of the heatpump model was found to be most influenced by the volumetric flow rate of the refrigerant, reaching a maximum of about 5.6 with a volumetric flow rate of 0.1m3/s. The volumetric heating/cooling capacity of the refrigerant was also found to be primarily influenced by the maximum enthalpy change in the refrigerant, with a maximum value of approximately 150J/s at an enthalpy change of 400kJ/kg. It was finally deduced that in order to attain optimal operation, the thermodynamic configuration of the heatpump should be such that to maximize the volumetric flow rate of the refrigerant, followed by its volumetric heating/cooling capacity, enthalpy change, and lastly, the density of the refrigerant. This study will provide published reviews for exclusive focus on the status of research on heat pumps with pure low-GWP refrigerants and no systematic application guidelines have been developed for these low-GWP vapor compression heat pumps. Therefore, refrigerants with high mass flow rate by virtue of their higher density, and high volumetric heating/cooling capacity by virtue of their specific heat capacity and high enthalpy change by virtue of their higher evaporation temperatures with lower condensation temperatures, such as the R-1234yf should be widely adopted for use in the air source heat pumps. These findings also suggest that whereas R134a provides reliable performance, refrigerants such as the R290, R1234yf, and R1234ze(E) offer a favorable balance between the energy efficiency and the environmental impact Table of Contents Contents TOC \o "1-3" \h \z \u Abstract PAGEREF _Toc173248446 \h 2Table of Contents PAGEREF _Toc173248447 \h 3List of Figures PAGEREF _Toc173248448 \h 5List of Tables PAGEREF _Toc173248449 \h 5List of Abbreviations and Mathematical Symbols PAGEREF _Toc173248450 \h 5Acknowledgements PAGEREF _Toc173248451 \h 61. INTRODUCTION PAGEREF _Toc173248452 \h 71.1 Background PAGEREF _Toc173248453 \h 71.2 Aim PAGEREF _Toc173248454 \h 71.3 Objectives PAGEREF _Toc173248455 \h 71.4 Specific Objectives PAGEREF _Toc173248456 \h 71.5 Justification PAGEREF _Toc173248457 \h 81.6 Relevance of the Study PAGEREF _Toc173248458 \h 81.7 Scope of the Study PAGEREF _Toc173248459 \h 82. LITERATURE REVIEW PAGEREF _Toc173248460 \h 92.1 Low GWP Refrigerants PAGEREF _Toc173248461 \h 92.1.1 Characteristics and Benefits PAGEREF _Toc173248462 \h 92.2 Air Source Heat Pumps (ASHPs) PAGEREF _Toc173248463 \h 92.2.1 Principles of Operation PAGEREF _Toc173248464 \h 92.2.2 Performance Metrics PAGEREF _Toc173248465 \h 92.3 Influence of Refrigerant Properties PAGEREF _Toc173248466 \h 92.3.1 Refrigerant Density PAGEREF _Toc173248467 \h 92.3.2 Volumetric Flow Rate PAGEREF _Toc173248468 \h 92.3.3 Enthalpy Change PAGEREF _Toc173248469 \h 92.4 Simulation Studies PAGEREF _Toc173248470 \h 102.4.1 MATLAB/SIMULINK for HVAC&R Systems PAGEREF _Toc173248471 \h 102.4.2 Case Studies and Experimental Validation PAGEREF _Toc173248472 \h 102.5 Environmental Impact and Regulations PAGEREF _Toc173248473 \h 102.5.1 Regulatory Frameworks PAGEREF _Toc173248474 \h 102.5.2 Life Cycle Climate Performance (LCCP) PAGEREF _Toc173248475 \h 103. METHODOLOGY PAGEREF _Toc173248476 \h 113.1 System Modeling and Simulation PAGEREF _Toc173248477 \h 113.1.1 Analytical Models PAGEREF _Toc173248478 \h 113.1.2 Heat Transfer Correlations PAGEREF _Toc173248479 \h 123.1.3 Factors Affecting Performance Metrics PAGEREF _Toc173248480 \h 123.1.4 Simulation Setup PAGEREF _Toc173248481 \h 133.2 User-Defined Functions PAGEREF _Toc173248482 \h 133.3 SIMULINK Model PAGEREF _Toc173248483 \h 143.3.1 Connectivity and Layout PAGEREF _Toc173248484 \h 153.4 Numerical Analysis and Graph Plotting PAGEREF _Toc173248485 \h 164. RESULTS PAGEREF _Toc173248486 \h 184.1 Parametric simulation results PAGEREF _Toc173248487 \h 184.1.1 Parametric simulation of the Analytical model in the Heating mode PAGEREF _Toc173248488 \h 184.1.2 Parametric simulation of the Analytical model in the Cooling mode PAGEREF _Toc173248489 \h 194.2 Analytical simulation results PAGEREF _Toc173248490 \h 204.2.1 Analytical model simulation in the Optimal Configuration locus, for the Heating mode PAGEREF _Toc173248491 \h 204.2.2 Analytical model simulation in the Optimal Configuration locus, for the Cooling mode PAGEREF _Toc173248492 \h 214.3 Analytical analysis PAGEREF _Toc173248493 \h 215. DISCUSSIONS PAGEREF _Toc173248494 \h 235.1 Overview of Simulation Results PAGEREF _Toc173248495 \h 235.2 Parametric simulation and analysis results in MATLAB/SIMULINK PAGEREF _Toc173248496 \h 235.3 Analysis of Volumetric Heating/Cooling Capacity PAGEREF _Toc173248497 \h 235.4 Influence of Independent Variables PAGEREF _Toc173248498 \h 245.4.1 Refrigerant Volumetric Flow Rate PAGEREF _Toc173248499 \h 245.4.2 Volumetric Heating/Cooling Capacity PAGEREF _Toc173248500 \h 246. CONCLUSIONS AND FUTURE WORK PAGEREF _Toc173248501 \h 256.1Conclusions PAGEREF _Toc173248502 \h 256.2Future Work PAGEREF _Toc173248503 \h 25References PAGEREF _Toc173248504 \h 27Appendix A: SIMULINK User-defined functions script code for the SIMULINK Simulation Air Source Heatpump Model PAGEREF _Toc173248505 \h 29Appendix B: MATLAB script code for the Analytical Analysis of the Analytical Modle of the Air Source Heatpump Model PAGEREF _Toc173248506 \h 32 List of Figures TOC \h \z \c "Figure" Figure 1: The inductive tracing of the the proportionality relations of both the target variables. A: The SIMULINK sine wave block and the gain block used to generate the signals, B: The SIMULINK scope graph for inductive simulation and analysis of the analytical model PAGEREF _Toc172429596 \h 14 Figure 2: The schematic flow chart of the analytical model of the air source heatpump PAGEREF _Toc172429597 \h 15 Figure 3: The SIMULINK model of the analytical model of the air source heatpump PAGEREF _Toc172429598 \h 15 Figure 4: Parametric simulation of the Analytical model in the Heating mode. A: The graph of Refrigerant density Vs Volumetric Heating Capacity Vs COP, B: The graph of Volumetric flow rate Vs Volumetric Heating Capacity Vs COP, C: The graph of Enthalpy change Vs Volumetric Heating Capacity Vs COP PAGEREF _Toc172429599 \h 18 Figure 5: Parametric simulation of the Analytical model in the Cooling mode. A: The graph of Refrigerant density Vs Volumetric Cooling Capacity Vs COP, B: The graph of Volumetric flow rate Vs Volumetric Cooling Capacity Vs COP, C: The graph of Enthalpy change Vs Volumetric Cooling Capacity Vs COP PAGEREF _Toc172429600 \h 19 Figure 6: Analytical model simulation in the Optimal Configuration locus, for the Heating mode. A: The graph of Refrigerant density, Volumetric Heating Capacity Vs COP, B: The graph of Volumetric flow rate Vs Volumetric Heating Capacity Vs COP, C: The graph of Enthalpy change Vs Volumetric Heating Capacity Vs COP PAGEREF _Toc172429601 \h 20 Figure 7: Analytical model simulation in the Optimal Configuration locus, for the Cooling mode. A: The graph of Refrigerant density Vs Volumetric Cooling Capacity Vs COP, B: The graph of Volumetric flow rate Vs Volumetric Cooling Capacity Vs COP, C: The graph of Enthalpy change Vs Volumetric Cooling Capacity Vs COP PAGEREF _Toc172429602 \h 21 Figure 8: Analysis of volumetric heating/cooling capacity PAGEREF _Toc172429603 \h 23 List of Tables TOC \h \z \c "Table" Table 1: Heating Mode Simulation Results PAGEREF _Toc172429604 \h 21 Table 2: Cooling Mode Simulation Results PAGEREF _Toc172429605 \h 22 List of Abbreviations and Mathematical Symbols Abbreviation/Quantity Unit Global Warming Potential (GWP) - Coefficient of Performance (COP) - Refrigerant heating/cooling capacity W Refrigerant density kg/m^3 Refrigerant volumetric flow rate m^3/s Enthalpy change in the evaporator (Δhevap ) kJ/kg Enthalpy change in the condenser (Δhcond) kJ/kg Enthalpy change across the compressor (Δhcomp) kJ/kg Acknowledgements I would like to thank [Supervisor/Professor Name] for their guidance and support through out this project. Special thanks to [Institution/Organization] for providing the necessary resources and tools. 1. INTRODUCTION 1.1 Background Due to economic development and population growth, global energy consumption has sharply increased, and the appropriate use of energy sources has become an important research topic for many countries. The increasing need for the environmentally friendly refrigerants has led to the exploration of the use...