Transcritical CO2 Heat Pump

XIN-RONG ZHANG, PHD, is Professor in the Department of Energy and Resources Engineering at Peking University in China. His contribution to this area includes not only the funda­mentals, such as flow and heat transfer of supercritical CO2; but also applications, designs of commercial and industrial CO2 heat pumps, novel CO2 re­frigeration cycle using solid-gas flow, and solar powered CO2 cogeneration system. He teaches a graduate course called “CO2 Refrigeration and Heat Pumps” at Peking University.HIROSHI YAMAGUCHI, PHD, is Professor in the Department of Mechanical Engineering at Doshisha University in Japan. He received his doctorate from the University of Manchester Institute of Science and Technology in the United Kingdom in 1982. His research focus is on fluid engineering, solar energy conversion, ultra-low temperature refrigeration, and magnetic fluids.

• List of ContributorsPrefaceChapter 1 Introduction1.1 Background1.2 Fundamentals1.3 Applications1.4 A guide to this bookChapter 2 Current development of CO2 heat pump2.1 Introduction2.2 CO2 properties2.3 Working principle of transcritical CO2 heat pump2.4 A brief history of CO2 heat pump2.5 CO2 cascade heat pump system2.6 Advanced CO2 heat pump system with an ejectorChapter 3 Fluid Dynamics and Heat Transfer of Supercritical Carbon Dioxide Cooling3.1 Supercritical properties3.2 Supercritical heat transfer fluid mechanics3.3 Supercritical gas cooling experiments3.4 Supercritical CO2 heat transfer correlations3.5 Supercritical CO2 pressure drop3.6 Supercritical CO2 heat transfer and pressure drop with lubricants3.7 Summary and need for additional researchChapter 4 Boiling flow and heat transfer of CO2 in an evaporator4.1 Introduction4.2 Boiling heat transfer of liquid CO2 in an evaporator4.3 Sublimation heat ransfer of dry ice-gas CO2 in an evaporator/sublimatorChapter 5 Theoretical analysis of CO2 expansion process5.1 Introduction5.2 Thermodynamic analysis of the expansion process in transcritical CO2 cycles5.3 Theory of ejector-expansion devices5.4 Expansion work recovery devices for transcritical CO2 systemsChapter 6 Trans-critical carbon dioxide compressors6.1 Introduction6.2 Sliding vane CO2 compressor6.3 Screw CO2 compressor6.4 CO2 rolling rotor compressor6.5 SCO2 scroll compressor6.6 SCO2 turbo-compressor6.7 SCO2 piston compressor6.8 Future trends6.9 Some key technical problems of CO2 compressor6.10 Conclusion and perspectivesChapter 7 CO2 subcooling7.1 Introduction7.2 CO2 thermodynamic properties and approach7.3 Internal heat exchanger7.4 Dedicated mechanical subcooling7.5 Integrated mechanical subcooling7.6 SummaryChapter 8 High temperature CO2 heat pump system and optimization8.1 Background8.2 Basic system design8.3 High temperature operation and key equipment8.4 System Optimization8.5 Applications and challenges8.6 Commercialized Products by High Temperature CO2 Heat Pump8.7 SummaryChapter 9 Performance Analysis and Optimization of a CO2 Heat Pump Water Heating System9.1 Introduction9.2 System configuration9.3 System modeling9.4 Numerical solution9.5 Conditions for performance analysis and optimization9.6 Performance analysis under periodically steady state9.7 Performance enhancement by extracting tepid water9.8 Performance analysis under unsteady state9.9 Performance estimation under unsteady state9.10 Performance optimization under unsteady state9.11 Other issues on performance analysis and optimizationChapter 10 Transcritical CO2 heat pump space heating10.1 Attempts towards the space heating used a transcritical CO2 heat pump10.2 Thermodynamic analysis of the subcooler based CO2 heat pump10.3 Comparison between the subcooler based CO2 system and the cascade cycle10.4 Optimal discharge pressure10.5 Optimal medium temperature10.6 Conclusion and prospectReferences