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 Contributors

Preface

Chapter 1 Introduction

1.1 Background

1.2 Fundamentals

1.3 Applications

1.4 A guide to this book

Chapter 2 Current development of CO2 heat pump

2.1 Introduction

2.2 CO2 properties

2.3 Working principle of transcritical CO2 heat pump

2.4 A brief history of CO2 heat pump

2.5 CO2 cascade heat pump system

2.6 Advanced CO2 heat pump system with an ejector

Chapter 3 Fluid Dynamics and Heat Transfer of Supercritical Carbon Dioxide Cooling

3.1 Supercritical properties

3.2 Supercritical heat transfer fluid mechanics

3.3 Supercritical gas cooling experiments

3.4 Supercritical CO2 heat transfer correlations

3.5 Supercritical CO2 pressure drop

3.6 Supercritical CO2 heat transfer and pressure drop with lubricants

3.7 Summary and need for additional research

Chapter 4 Boiling flow and heat transfer of CO2 in an evaporator

4.1 Introduction

4.2 Boiling heat transfer of liquid CO2 in an evaporator

4.3 Sublimation heat ransfer of dry ice-gas CO2 in an evaporator/sublimator

Chapter 5 Theoretical analysis of CO2 expansion process

5.1 Introduction

5.2 Thermodynamic analysis of the expansion process in transcritical CO2 cycles

5.3 Theory of ejector-expansion devices

5.4 Expansion work recovery devices for transcritical CO2 systems

Chapter 6 Trans-critical carbon dioxide compressors

6.1 Introduction

6.2 Sliding vane CO2 compressor

6.3 Screw CO2 compressor

6.4 CO2 rolling rotor compressor

6.5 SCO2 scroll compressor

6.6 SCO2 turbo-compressor

6.7 SCO2 piston compressor

6.8 Future trends

6.9 Some key technical problems of CO2 compressor

6.10 Conclusion and perspectives

Chapter 7 CO2 subcooling

7.1 Introduction

7.2 CO2 thermodynamic properties and approach

7.3 Internal heat exchanger

7.4 Dedicated mechanical subcooling

7.5 Integrated mechanical subcooling

7.6 Summary

Chapter 8 High temperature CO2 heat pump system and optimization

8.1 Background

8.2 Basic system design

8.3 High temperature operation and key equipment

8.4 System Optimization

8.5 Applications and challenges

8.6 Commercialized Products by High Temperature CO2 Heat Pump

8.7 Summary

Chapter 9 Performance Analysis and Optimization of a CO2 Heat Pump Water Heating System

9.1 Introduction

9.2 System configuration

9.3 System modeling

9.4 Numerical solution

9.5 Conditions for performance analysis and optimization

9.6 Performance analysis under periodically steady state

9.7 Performance enhancement by extracting tepid water

9.8 Performance analysis under unsteady state

9.9 Performance estimation under unsteady state

9.10 Performance optimization under unsteady state

9.11 Other issues on performance analysis and optimization

Chapter 10 Transcritical CO2 heat pump space heating

10.1 Attempts towards the space heating used a transcritical CO2 heat pump

10.2 Thermodynamic analysis of the subcooler based CO2 heat pump

10.3 Comparison between the subcooler based CO2 system and the cascade cycle

10.4 Optimal discharge pressure

10.5 Optimal medium temperature

10.6 Conclusion and prospect

References