Experimental study on thermal and flow performance of staggered tube-bundle heat exchanger for seawater source heat pump

On the basis of the hot-gas bypass defrost cycle, a new defrost method for air source heat pump is proposed. In the new defrost cycle, the outdoor heat exchanger is divided into two parts which are connected by a capillary tube. The front and rear parts of the heat exchanger are used as the evaporator and condenser respectively during defrosting, and can be defrosted orderly by using the four-way valve. The defrosting performance of the new cycle is investigated experimentally and the results are compared with that of the reverse-cycle defrost system. The experimental results indicate that the energy is used more efficiently in the new defrost cycle, therefore, the defrosting duration and losses are less than those of the reverse-cycle defrost system. Moreover, it does not extract heat from the indoor space during defrosting in terms of the new defrost cycle. Compared with the reverse-cycle defrost system, it is found that the switching times of the four-way valve in the new defrost system are the same, and the fluctuation of the discharge and suction pressures during the defrosting is much less than that in the reverse-cycle defrosting, hence, the mechanical impact on the system is much less.

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Experimental study on vapor injection air source heat pump with internal heat exchanger for electric bus

Energy Procedia ◽

10.1016/j.egypro.2019.01.817 ◽

2019 ◽

Vol 158 ◽

pp. 4147-4153 ◽

Cited By ~ 1

Author(s):

Xinxin Han ◽

Huiming Zou ◽

Hongbo Xu ◽

Changqing Tian ◽

Wei Kang

Keyword(s):

Experimental Study ◽

Heat Exchanger ◽

Heat Pump ◽

Internal Heat ◽

Air Source Heat Pump ◽

Internal Heat Exchanger ◽

Electric Bus ◽

Vapor Injection

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Experimental Study on Characteristics of False Defrosting for Split Air Source Heat Pump

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.220-223.585 ◽

2012 ◽

Vol 220-223 ◽

pp. 585-591

Author(s):

Rui Chao Tang ◽

Zhi Tao Han ◽

Er Kang Zhang ◽

Shu Guang Liu ◽

Hai Quan Zhang ◽

...

Keyword(s):

Experimental Study ◽

Heat Exchanger ◽

Heat Pump ◽

Control Method ◽

Temperature Sensors ◽

Air Conditioner ◽

Air Source Heat Pump ◽

Shaft Power ◽

Discharge Pressure ◽

Two Temperature

Detailed experimental study on the characteristics of false defrosting of a split type air-source heat pump (ASHP) has been made. The results show that the false defrosting is seriously detrimental to ASHP by comparing varied parameters of compressor such as shaft power, suction and discharge pressure, etc. in normal defrosting and false defrosting. This paper also analyzes a common defrosting control method for air conditioner of split ASHP room, i.e., with two temperature sensors set on indoor heat exchanger, the operating principle thereof and drawbacks in terms of causing false defrosting.

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