Theoretical analysis and experimental study on optimal exhaust pressure for CO₂ heat pump

Authors

LIU Xiao-ting, College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China; Shanghai Professional Technology Service Platform on Cold Chain Equipment Performance and Energy Saving Evaluation, Shanghai 201306, China
GU Zhong, College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China; Shanghai Professional Technology Service Platform on Cold Chain Equipment Performance and Energy Saving Evaluation, Shanghai 201306, China
XIE Jing, College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China; Shanghai Professional Technology Service Platform on Cold Chain Equipment Performance and Energy Saving Evaluation, Shanghai 201306, China; Shanghai Engineering Research Center of Aquatic Product Processing & Preservation, Shanghai 201306, China; National Experimental Teaching Demonstration Center for Food Science and Engineering 〔Shanghai Ocean University〕, Shanghai 201306, ChinaFollow

Corresponding Author(s)

谢晶（1968—），女，上海海洋大学教授，博士。E-mail:jxie@shou.edu.cn

Abstract

Objective: This study aimed to optimize the performance of heat pump system and discuss the optimal exhaust pressure of carbon dioxide system under the control of different working conditions. Methods: By establishing a CO₂ trans-critical heat pump model, the relationship between exhaust pressure and heat production, inspiratory superheat, refrigerant mass flow rate and system energy efficiency was analyzed, and the influence of inlet and outlet water temperature and ambient temperature on the optimal exhaust pressure was deeply studied. Moreover, the reliability of the model was verified by the CO₂ heat pump test bench. Results: At the three effluent temperatures, the heat production increased with the increase of exhaust pressure, and the mass flow rate decreased with the increase of exhaust pressure. The cycle performance coefficient and superheat showed a trend of first increasing and then decreasing with the increase of exhaust pressure, the optimal exhaust pressure increased with the increase of inlet and outlet water temperature and ambient temperature, but the increase of inlet and outlet water temperature reduced the system cycle performance coefficient. Based on this, the optimal exhaust pressure correlation formula at the outlet temperature of 60 ℃ was fitted, and five groups of tests were designed to prove its reliability. Conclusion: The optimal exhaust pressure of the system is determined by a large number of simulation data, and compared with the test values, it is found that the error values are less than 5%, which meets the test and design requirements.

Publication Date

6-9-2023

First Page

70

Last Page

76

DOI

10.13652/j.spjx.1003.5788.2022.80926

Recommended Citation

Xiao-ting, LIU; Zhong, GU; and Jing, XIE (2023) "Theoretical analysis and experimental study on optimal exhaust pressure for CO₂ heat pump," Food and Machinery: Vol. 39: Iss. 5, Article 12.
DOI: 10.13652/j.spjx.1003.5788.2022.80926
Available at: https://www.ifoodmm.cn/journal/vol39/iss5/12

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