Frosting for Air Source Heat Pumps

Research, Case Studies, and Methods

1st Edition - October 24, 2024
Authors: Mengjie Song, Long Zhang
Language: English
Paperback ISBN:
9 7 8 - 0 - 3 2 3 - 9 5 4 5 7 - 0
eBook ISBN:
9 7 8 - 0 - 3 2 3 - 9 5 4 5 8 - 7

Frosting for Air Source Heat Pumps: Research, Case Studies, and Methods provides a comprehensive accounting of the latest research, analysis, and modeling methods for limiti… Read more

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Frosting for Air Source Heat Pumps: Research, Case Studies, and Methods provides a comprehensive accounting of the latest research, analysis, and modeling methods for limiting frosting and maximizing efficiency. The book begins by outlining the fundamentals of frosting mechanisms, including the condensation and freezing of water droplets. It then provides a wide range of case studies that showcase a variety of surfaces, conditions, and energy generation technologies. Finally, the last chapters demonstrate modeling and analysis of frosting operation before laying out critical considerations for designing a frost control strategy in ASHPs.

Building on the theory and studies contained in the author’s previous work Defrosting for Air Source Heat Pumps, this book provides essential and advanced information for understanding and controlling frosting for these sustainable energy sources.

Frosting for Air Source Heat Pumps
Cover image
Title page
Table of Contents
Copyright
Chapter 1 Introduction of frosting
Abstract
Keywords
1.1 Background of frosting in an air source heat pump (ASHP) unit
1.2 Frost formation process
1.3 Frosting phenomenon and its negative effect
1.3.1 Aerospace field
1.3.2 Aviation field
1.3.3 Liquefied natural gas (LNG) field
1.4 Data analysis of frosting studies
1.5 Objectives and scopes
1.5.1 Freezing of sessile nondeformed water droplet under natural convection on a horizontal cold plate
1.5.2 Freezing of sessile deformed water droplet under natural convection on a nonhorizontal cold plate
1.5.3 Frosting on a horizontal cold plate under natural convection
1.5.4 Frosting on a nonhorizontal cold plate under natural convection
1.5.5 Frosting on a horizontal cold plate under forced convection
1.5.6 Measurement and calculation of frosting characteristics and the recent development of these technologies
1.5.7 Frosting experiment on the surface of fin-tubed heat exchanger
1.5.8 Frosting model on the surface of fin-tubed heat exchanger
1.5.9 Frosting on surface of microchannel evaporator
1.5.10 Reverse cycle defrosting (RCD) for multicircuit outdoor coil
1.6 Book outline
References
Chapter 2 Freezing of sessile nondeformed water droplet under natural convection at early frosting stage in an ASHP unit
Abstract
Keywords
2.1 Introduction
2.2 Theoretical model for the solidification of sessile water droplet
2.2.1 Development of the theoretical model
2.2.2 Calculation process of the droplet profile
2.2.3 Validation of the developed model
2.3 Freezing behaviors during the solidification process of water droplet
2.3.1 Eccentricity evolution during the droplet freezing process
2.3.2 Evolutions of freezing front radius and mixture volume
2.3.3 Initial and final profiles of sessile water droplets
2.3.4 Final freezing times under various conditions
2.3.5 Evolutions of temperatures inside water droplets for different conditions
2.4 Modeling study on the frozen water droplet based on a theoretical model with a curved freezing front
2.4.1 Methodology
2.4.2 The whole process of the developed model
2.4.3 Validation of the developed model
2.4.4 Results and analysis
2.5 Concluding remarks
References
Chapter 3 Freezing of sessile deformed water droplet under natural convection at early frosting stage in an ASHP unit
Abstract
Keywords:
3.1 Introduction
3.2 Initial droplet profile on inclined surface
3.2.1 Experimental setup, procedures and conditions
3.2.2 Modeling work
3.2.3 Results and analysis
3.2.4 Conclusions
3.3 Freezing process of droplets on inclined surface
3.3.1 Experimental setup
3.3.2 Modeling work
3.3.3 Results and analysis
3.4 Summary
References
Chapter 4 Frosting on surface of horizontal cold plate under natural convection in an ASHP unit
Abstract
Keywords
4.1 Introduction
4.2 Whole frosting process in a simple cold plate
4.3 Modeling work on the early frosting stage
4.3.1 Theoretical model of frost layer thickness
4.3.2 Theoretical basis of emphasis on early frosting conditions
4.3.3 Results of influence of each factor on early frosting conditions
4.4 Frost characteristics on horizontal cold plate
4.4.1 Experimental work
4.4.2 Frosting characteristics at different surface temperatures
4.4.3 Frosting characteristics at different surface wettability
4.5 Discussions
4.5.1 Prediction of leaf-shaped frost thickness
4.5.2 Relationship between frost crystal growth characteristics and surface wettability
4.6 Concluding remarks
References
Chapter 5 Frosting on surface of nonhorizontal cold plate under natural convection in an ASHP unit
Abstract
Keywords:
5.1 Introduction
5.2 Experimental work
5.2.1 Experimental procedures and conditions
5.2.2 Data reduction
5.3 Frost process on nonhorizontal cold plate
5.3.1 Frosting stages
5.3.2 Reverse melting
5.4 Frost characteristics on nonhorizontal cold plate
5.4.1 Frost thickness
5.4.2 Frost layer surface roughness
5.4.3 Dynamic frosting rate
5.4.4 Frost density
5.5 Summary
References
Chapter 6 Frosting on surface of horizontal cold flat plate under forced convection in an ASHP unit
Abstract
Keywords
6.1 Introduction
6.2 Frosting characteristics at different air velocities
6.2.1 Experimentations
6.2.2 Results and analysis
6.3 Frosting characteristics at different initial cooling rates
6.3.1 Experimental cases
6.3.2 Results and analysis
6.4 Frosting characteristics at different cold plate temperatures
6.4.1 Experimental cases
6.4.2 Results and analysis
6.5 Summary
References
Chapter 7 Measurement and calculation of frost characteristics on cold surfaces
Abstract
Keywords
7.1 Introduction
7.2 Frost layer thickness and frosting rate
7.2.1 Measurement with physical methods
7.2.2 Frost layer thickness calculations and measurement influence
7.3 Frost accumulation and density
7.3.1 Frost accumulation measurement
7.3.2 Frost density calculation
7.4 Frost thermal conductivity and morphology
7.4.1 Frost thermal conductivity
7.4.2 Frost morphology
7.5 Heat and mass transfer coefficient
7.5.1 Convection heat transfer coefficient
7.5.2 Convection mass transfer coefficient
7.6 Summary
References
Chapter 8 Experimental case studies of frosting on surface of finned tube heat exchangers in an ASHP unit
Abstract
Keywords:
8.1 Introduction
8.2 Spatio-temporal frosting characteristics on FTHXs at a typical condition
8.2.1 Experimentations
8.2.2 Results and analysis
8.3 Effects of fan control modes on frosting characteristics on an FTHX
8.3.1 Experimental cases
8.3.2 Results and analysis
8.4 Effects of frosting conditions on frost distribution and growth on FTHXs
8.4.1 Experimental cases
8.4.2 Results and analysis
8.5 Summary
References
Chapter 9 Numerical case studies of frosting on surface of finned tube heat exchanger in an ASHP unit
Abstract
Keywords:
9.1 Introduction
9.2 A modeling study of frost growth on the edge of windward fins
9.2.1 Model development and validation
9.2.2 Results and analysis
9.3 A modeling study of frost growth on the entire FTHX
9.3.1 Model development and validation
9.3.2 Results and analysis
9.4 Summary
References
Chapter 10 Frosting case studies on surface of micro-channel heat exchanger
Abstract
Keywords
10.1 Introduction
10.2 Experimental setups
10.2.1 Micro-channel heat exchangers used for experiments
10.2.2 Principle of the experimental setups
10.2.3 Measuring points and experimental data acquisition system
10.3 Experimental results
10.3.1 Frost and temperature distribution on the heat exchanger
10.3.2 Heat transfer performance of heat exchanger
10.3.3 Performance and characteristic of micro-channel evaporator
10.4 Summary
References
Chapter 11 Reverse cycle defrosting case studies for multicircuit outdoor coil
Abstract
Keywords
11.1 Introduction
11.2 Experimental study on optimization of defrosting performance
11.2.1 Component optimization
11.2.2 Phase change thermal storage defrosting
11.2.3 Uneven defrosting research
11.2.4 Other studies on RCD enhancement
11.3 Numerical study on optimization of defrosting performance
11.3.1 The study on modeling of system and components
11.3.2 Research on the models of outdoor multicircuit heat exchanger
11.4 Development of RCD control strategy
11.4.1 The defrosting initiating control strategy
11.4.2 The defrosting terminating control strategy
11.5 Summary
References
Chapter 12 Conclusions and future work
Abstract
Keywords
12.1 Conclusions of the present work
12.2 Proposal of the future work
Index

Mengjie Song

Mengjie Song is a Professor in the Department of Energy and Power Engineering, as well as a Teli Young Scholar and the Director of the Frost Lab in the School of Mechanical Engineering at the Beijing Institute of Technology, China. He is also the Editor-in-Chief of Recent Patents on Mechanical Engineering (EI, Scopus), Associate Editor of Frontiers in Energy Research (SCI, IF=2.746). He also works as DECRA Research Fellow at the Sustainable Buildings Research Centre (SBRC) in the Faculty of Engineering and Information Sciences at the University of Wollongong, Australia, and as a Guest Professor of Tomas Bata University in the Czech Republic. Prof. Song has worked for over a decade on the mechanism study of heat and mass transfer coupled with flow. On the topic of frosting and defrosting for air source heat pump, he proposed a series of definitions to describe thermophysical phenomena, such as even/uneven frosting/defrosting, and frosting/defrosting evenness value. His current research interests include solidification of water droplets at different scales and (anti-/de)icing for aircraft surface, and frosting and defrosting for a multi-circuit heat exchanger in refrigeration systems. He has published 122 journal articles and participated in projects from China, Hong Kong, Singapore, Japan, and Australia, handling a total of over 17 million yuan in funding, including 12 as PI. Recently, he was selected for the World’s Top 2% Scientists 2021 (Singleyr) list.

Affiliations and expertise

JSPS Research Fellow, Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Japan

Long Zhang

Doctor Long ZHANG is an Assistant Professor in the Department of Energy and Power Engineering at the Beijing Institute of Technology, China. He received his Ph.D. degrees from both The Hong Kong Polytechnic University and Harbin Institute of Technology, China. His research interests are the coupling mechanism and application research of heat and mass transfer and flow, especially the phase change problems such as frosting, icing, and the key technology research of heat pumps. He has published more than 50 SCI journal articles, including 32 ones as lead/corresponding author and 2 ESI ones. He also published 2 books and 2 chapters for Elsevier, applied for 8 Chinese patents, and made 6 invited presentations at international and Chinese conferences around frosting and icing topics. Additionally, he holds more than 10 projects, including the National Natural Science Foundation of China.

Affiliations and expertise

Postdoctoral Fellow, Department of Energy and Power Engineering, Beijing Institute of Technology, China

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