Numerical study of a direct-expansion solar-assisted heat pump water heater under frosting conditions based on experiments

Solar Energy ◽  
2020 ◽  
Vol 196 ◽  
pp. 10-21 ◽  
Author(s):  
Xiangqiang Kong ◽  
Jinyu Li ◽  
Baigong Wang ◽  
Ying Li
Keyword(s):  
Heat Pump ◽  
Numerical Study ◽  
Direct Expansion ◽  
Water Heater ◽  
Heat Pump Water Heater

Control strategy and experimental analysis of a direct-expansion solar-assisted heat pump water heater with R134a

Energy ◽  
2018 ◽  
Vol 145 ◽  
pp. 17-24 ◽  
Author(s):  
Xiangqiang Kong ◽  
Kailin Jiang ◽  
Shandong Dong ◽  
Ying Li ◽  
Jianbo Li
Keyword(s):  
Heat Pump ◽  
Control Strategy ◽  
Experimental Analysis ◽  
Direct Expansion ◽  
Water Heater ◽  
Heat Pump Water Heater

scholarly journals Numerical study on the influence of internal heat exchanger in transcritical CO2 heat pumps under optimal pressure conditions

2021 ◽  
Vol 2116 (1) ◽  
pp. 012098
Author(s):  
F Illán-Gómez ◽  
J R García-Cascales ◽  
F J Sánchez-Velasco ◽  
V Sena-Cuevas ◽  
R Otón-Martínez
Keyword(s):  
Heat Exchanger ◽  
Heat Pump ◽  
Strong Influence ◽  
Numerical Study ◽  
Internal Heat ◽  
Heat Pumps ◽  
Operating Conditions ◽  
Water Heater ◽  
Internal Heat Exchanger ◽  
Heat Pump Water Heater

Abstract This paper presents a numerical study on the influence of internal heat exchanger (IHX) exchanging surface in the performance of a transcritical CO2 heat pump water heater at different operating conditions. Five different IHX geometries and four different evaporation temperatures have been studied with water temperature ranging from 10 °C to 60 °C at the gas cooler inlet. The results show a strong influence of IHX characteristics on system’s performance.

scholarly journals Experimental Study of a Novel Direct-Expansion Variable Frequency Finned Solar/Air-Assisted Heat Pump Water Heater

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Jing Qin ◽  
Jie Ji ◽  
Wenzhu Huang ◽  
Hong Qin ◽  
Mawufemo Modjinou ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Ambient Temperature ◽  
Heat Pump ◽  
Operating Mode ◽  
Heating Time ◽  
Solar Irradiation ◽  
Variable Frequency ◽  
Direct Expansion ◽  
Water Heater ◽  
Heat Pump Water Heater

A novel direct expansion variable frequency finned solar/air-assisted heat pump water heater was fabricated and tested in the enthalpy difference lab with a solar simulator. A solar/air source evaporator-collector with an automatic lifting glass cover plate was installed on the system. The system could be operated in three modes, namely, air, solar, and dual modes. The effects of the ambient temperature, solar irradiation, compressor frequency, and operating mode on the performance of this system were studied in this paper. The experimental results show that the ambient temperature, solar irradiation, and operating mode almost have no effect on the energy consumption of the compressor. When the ambient temperature and the solar irradiation were increased, the COP was found to increase with decreasing heating time. Also, when the compressor frequency was increased, an increase in the energy consumption of the compressor and the heat gain of the evaporator were noted with a decrease in the heating time.

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