High-Temperature Heat Pump Using CO2-Based Mixture for Simultaneous Heat and Cold Energy Reservation

Chengyu Li; Yongzhen Wang; Qiang Guo; Youtang Wang; Hu Chen

doi:10.3390/en16186587

High-Temperature Heat Pump Using CO₂-Based Mixture for Simultaneous Heat and Cold Energy Reservation

Chengyu Li, Yongzhen Wang^*, Qiang Guo, Youtang Wang^*, Hu Chen

^*Corresponding author for this work

School of Mechanical Engineering

Research output: Contribution to journal › Article › peer-review

1 Citation (Scopus)

Abstract

To leverage temperature glide in evaporation, a transcritcal heat pump using a CO₂-based mixture is investigated from a perspective of simultaneous heat and cold energy storage. Coefficient of performance for heating (COP_h) and exergy efficiency are used to evaluate system performance. A parametric investigation on the heat pump is conducted, and the coupling behavior of the cycle with thermal energy storage (TES) material is investigated in view of stored exergy of TES. Optimization and comparative studies are carried out among various mixtures. The results reveal that maximum cycle temperature is mainly affected by high pressure and superheating degree, while minimum cycle temperature, as well as cold exergy, is highly dependent on evaporating temperature glide, with little influence from high pressure. The total exergy efficiency can reach up to 60%. The temperature of low temperature TES could reach as low as −32.4 °C for CO₂/R601, providing the largest proportion of cold exergy to total exergy, up to 30.1%.

Original language	English
Article number	6587
Journal	Energies
Volume	16
Issue number	18
DOIs	https://doi.org/10.3390/en16186587
Publication status	Published - Sept 2023

Keywords

CO-based mixture
cold exergy
heat pump
thermal energy storage

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

Access to Document

10.3390/en16186587

Cite this

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title = "High-Temperature Heat Pump Using CO2-Based Mixture for Simultaneous Heat and Cold Energy Reservation",

abstract = "To leverage temperature glide in evaporation, a transcritcal heat pump using a CO2-based mixture is investigated from a perspective of simultaneous heat and cold energy storage. Coefficient of performance for heating (COPh) and exergy efficiency are used to evaluate system performance. A parametric investigation on the heat pump is conducted, and the coupling behavior of the cycle with thermal energy storage (TES) material is investigated in view of stored exergy of TES. Optimization and comparative studies are carried out among various mixtures. The results reveal that maximum cycle temperature is mainly affected by high pressure and superheating degree, while minimum cycle temperature, as well as cold exergy, is highly dependent on evaporating temperature glide, with little influence from high pressure. The total exergy efficiency can reach up to 60%. The temperature of low temperature TES could reach as low as −32.4 °C for CO2/R601, providing the largest proportion of cold exergy to total exergy, up to 30.1%.",

keywords = "CO-based mixture, cold exergy, heat pump, thermal energy storage",

author = "Chengyu Li and Yongzhen Wang and Qiang Guo and Youtang Wang and Hu Chen",

note = "Publisher Copyright: {\textcopyright} 2023 by the authors.",

year = "2023",

month = sep,

doi = "10.3390/en16186587",

language = "English",

volume = "16",

journal = "Energies",

issn = "1996-1073",

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T1 - High-Temperature Heat Pump Using CO2-Based Mixture for Simultaneous Heat and Cold Energy Reservation

AU - Li, Chengyu

AU - Wang, Yongzhen

AU - Guo, Qiang

AU - Wang, Youtang

AU - Chen, Hu

PY - 2023/9

Y1 - 2023/9

N2 - To leverage temperature glide in evaporation, a transcritcal heat pump using a CO2-based mixture is investigated from a perspective of simultaneous heat and cold energy storage. Coefficient of performance for heating (COPh) and exergy efficiency are used to evaluate system performance. A parametric investigation on the heat pump is conducted, and the coupling behavior of the cycle with thermal energy storage (TES) material is investigated in view of stored exergy of TES. Optimization and comparative studies are carried out among various mixtures. The results reveal that maximum cycle temperature is mainly affected by high pressure and superheating degree, while minimum cycle temperature, as well as cold exergy, is highly dependent on evaporating temperature glide, with little influence from high pressure. The total exergy efficiency can reach up to 60%. The temperature of low temperature TES could reach as low as −32.4 °C for CO2/R601, providing the largest proportion of cold exergy to total exergy, up to 30.1%.

AB - To leverage temperature glide in evaporation, a transcritcal heat pump using a CO2-based mixture is investigated from a perspective of simultaneous heat and cold energy storage. Coefficient of performance for heating (COPh) and exergy efficiency are used to evaluate system performance. A parametric investigation on the heat pump is conducted, and the coupling behavior of the cycle with thermal energy storage (TES) material is investigated in view of stored exergy of TES. Optimization and comparative studies are carried out among various mixtures. The results reveal that maximum cycle temperature is mainly affected by high pressure and superheating degree, while minimum cycle temperature, as well as cold exergy, is highly dependent on evaporating temperature glide, with little influence from high pressure. The total exergy efficiency can reach up to 60%. The temperature of low temperature TES could reach as low as −32.4 °C for CO2/R601, providing the largest proportion of cold exergy to total exergy, up to 30.1%.

KW - CO-based mixture

KW - cold exergy

KW - heat pump

KW - thermal energy storage

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