TY - JOUR
TI - Influence of opening of electronic expansion valve on heating performance of vehicle heat pump system with economizer
AU - Li Haijun
AU - Chen Gang
AU - Su Zhiyong
AU - Zhang Yibo
AU - Gao Jiayang
AU - Niu Ruikai
AU - Cheng Long
AU - Yin Shuguang
JN - Thermal Science
PY - 2026
VL - 30
IS - 2
SP - 993
EP - 1003
PT - Article
AB - The objective of this study was to investigate the impact of the electronic  expansion valve opening in an automotive heat pump system with an  economizer on the system winter heating performance and frost-related  characteristics. The experiments were conducted at a temperature of -10°C  during the winter months. The adjustment of the opening degrees of the main  and complementary electronic expansion valve was implemented to facilitate  an analysis of the heating performance parameters and the alterations in  frost formation and melting. The findings demonstrated that a diminution in  the main circuit electronic expansion valve opening from 40% to 24% resulted  in an augmentation of the exhaust gas temperature by 12.24°C, accompanied  by a maximum heat production of 2.837 kW and a COP of 1.99. In the low  pressure makeup mode, an increase in the makeup electronic valve opening  from 8% to 15% resulted in a 7.27°C decrease in the exhaust gas  temperature. Concurrently, the maximum heat production and the COP reached  2.851 kW and 2, respectively. In the medium pressure makeup mode, an  increase in the makeup electronic valve opening from 8% to 20% resulted in a  9.4°C reduction in the exhaust temperature. This adjustment resulted in a  maximum heat production of 3.235 kW and a COP of 1.96. In consideration of  the subject of frost-related phenomena, the following observations were  made: the duration required to execute frosting in the no-makeup gas, low  pressure makeup gas, and medium pressure makeup gas modes was 82 minutes, 90  minutes, and 95 minutes, respectively. The duration required for frost  melting was determined to be 5 minutes and 20 seconds, 4 minutes and 30  seconds, and 3 minutes, and 56 seconds, respectively. These findings offer  significant insights in-to the optimization of automotive heat pump systems  during winter operations.
DO - 10.2298/TSCI2602993L
ER -