Experimental Study on Air-Source Heat Pump Alternate Defrosting with Multiple Outdoor Units in Parallel

An experimental system of an air-source heat pump with multiple outdoor units in parallel was designed and built. The outdoor units were defrosted in turn using hot subcooled liquid for defrosting. The heat pump heating performance variations in the course of frosting and defrosting under different...

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Main Authors: Niu Jianhui, Liang Zheng, Liu Fusheng, Ma Guoyuan, Feng Lianyuan
Format: Article
Language:zho
Published: Journal of Refrigeration Magazines Agency Co., Ltd. 2024-12-01
Series:Zhileng xuebao
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Online Access:http://www.zhilengxuebao.com/thesisDetails#10.12465/j.issn.0253-4339.2024.06.158
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author Niu Jianhui
Liang Zheng
Liu Fusheng
Ma Guoyuan
Feng Lianyuan
author_facet Niu Jianhui
Liang Zheng
Liu Fusheng
Ma Guoyuan
Feng Lianyuan
author_sort Niu Jianhui
collection DOAJ
description An experimental system of an air-source heat pump with multiple outdoor units in parallel was designed and built. The outdoor units were defrosted in turn using hot subcooled liquid for defrosting. The heat pump heating performance variations in the course of frosting and defrosting under different outdoor temperature and humidity conditions were experimentally studied, and the heating performances of the hot liquid subcooling alternate defrosting system and hot gas bypass alternate defrosting system were compared and analyzed. The experimental results show that the hot liquid subcooling alternate defrosting can enable the heat pump to complete the defrosting under the condition of continuous heating and that the defrosting performance is good. When the outdoor air temperature is -10 ℃ and the relative humidity is 90%, the optimal time to start defrosting is 30 min. At this time, the system heating capacity decreases from 9.87 kW when there is no frost to 8.71 kW when the defrosting starts, and the heating COP decreases from 3.73 to 3.36. When the system operates defrosting under different humidity conditions, the minimum values of system heating capacity and heating COP can reach 5.42 kW and 2.28, respectively. Compared to the case of bypassing 20% of discharge gas for defrosting, the average heating capacity of hot liquid subcooling alternate defrosting is 13.8% higher, and the heating COP<sub>C</sub> is 10.1% higher.
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issn 0253-4339
language zho
publishDate 2024-12-01
publisher Journal of Refrigeration Magazines Agency Co., Ltd.
record_format Article
series Zhileng xuebao
spelling doaj-art-e4f5b1052e124923a14bdc5c030f45b42025-08-20T03:15:54ZzhoJournal of Refrigeration Magazines Agency Co., Ltd.Zhileng xuebao0253-43392024-12-014515816678553575Experimental Study on Air-Source Heat Pump Alternate Defrosting with Multiple Outdoor Units in ParallelNiu JianhuiLiang ZhengLiu FushengMa GuoyuanFeng LianyuanAn experimental system of an air-source heat pump with multiple outdoor units in parallel was designed and built. The outdoor units were defrosted in turn using hot subcooled liquid for defrosting. The heat pump heating performance variations in the course of frosting and defrosting under different outdoor temperature and humidity conditions were experimentally studied, and the heating performances of the hot liquid subcooling alternate defrosting system and hot gas bypass alternate defrosting system were compared and analyzed. The experimental results show that the hot liquid subcooling alternate defrosting can enable the heat pump to complete the defrosting under the condition of continuous heating and that the defrosting performance is good. When the outdoor air temperature is -10 ℃ and the relative humidity is 90%, the optimal time to start defrosting is 30 min. At this time, the system heating capacity decreases from 9.87 kW when there is no frost to 8.71 kW when the defrosting starts, and the heating COP decreases from 3.73 to 3.36. When the system operates defrosting under different humidity conditions, the minimum values of system heating capacity and heating COP can reach 5.42 kW and 2.28, respectively. Compared to the case of bypassing 20% of discharge gas for defrosting, the average heating capacity of hot liquid subcooling alternate defrosting is 13.8% higher, and the heating COP<sub>C</sub> is 10.1% higher.http://www.zhilengxuebao.com/thesisDetails#10.12465/j.issn.0253-4339.2024.06.158air-source heat pumphot liquid defrostinghot gas defrostingheating performance
spellingShingle Niu Jianhui
Liang Zheng
Liu Fusheng
Ma Guoyuan
Feng Lianyuan
Experimental Study on Air-Source Heat Pump Alternate Defrosting with Multiple Outdoor Units in Parallel
Zhileng xuebao
air-source heat pump
hot liquid defrosting
hot gas defrosting
heating performance
title Experimental Study on Air-Source Heat Pump Alternate Defrosting with Multiple Outdoor Units in Parallel
title_full Experimental Study on Air-Source Heat Pump Alternate Defrosting with Multiple Outdoor Units in Parallel
title_fullStr Experimental Study on Air-Source Heat Pump Alternate Defrosting with Multiple Outdoor Units in Parallel
title_full_unstemmed Experimental Study on Air-Source Heat Pump Alternate Defrosting with Multiple Outdoor Units in Parallel
title_short Experimental Study on Air-Source Heat Pump Alternate Defrosting with Multiple Outdoor Units in Parallel
title_sort experimental study on air source heat pump alternate defrosting with multiple outdoor units in parallel
topic air-source heat pump
hot liquid defrosting
hot gas defrosting
heating performance
url http://www.zhilengxuebao.com/thesisDetails#10.12465/j.issn.0253-4339.2024.06.158
work_keys_str_mv AT niujianhui experimentalstudyonairsourceheatpumpalternatedefrostingwithmultipleoutdoorunitsinparallel
AT liangzheng experimentalstudyonairsourceheatpumpalternatedefrostingwithmultipleoutdoorunitsinparallel
AT liufusheng experimentalstudyonairsourceheatpumpalternatedefrostingwithmultipleoutdoorunitsinparallel
AT maguoyuan experimentalstudyonairsourceheatpumpalternatedefrostingwithmultipleoutdoorunitsinparallel
AT fenglianyuan experimentalstudyonairsourceheatpumpalternatedefrostingwithmultipleoutdoorunitsinparallel