An experimental study on achieving even-frosting for an air source heat pump using a novel dual-fan outdoor coil

被引：23

作者：

Bai, Xiaoxia ^{[1
]}

Liu, Shengnan ^{[1
]}

Deng, Shiming ^{[2
]}

Zhang, Long ^{[3
]}

Wei, Minchen ^{[1
]}

机构：

[1] Hong Kong Polytech Univ, Dept Bldg Serv Engn, Hong Kong, Peoples R China

[2] Qatar Univ, Dept Mech & Ind Engn, POB 2713, Doha, Qatar

[3] Beijing Inst Technol, Sch Mech Engn, Dept Energy & Power Engn, Beijing, Peoples R China

来源：

ENERGY AND BUILDINGS | 2022年 / 255卷

关键词：

Air source heat pump; Even frosting; Novel dual-fan outdoor coil; Alternate operation; Frosting duration; Defrosting frequency; DEFROSTING CHARACTERISTICS; WATER-RETENTION; PERFORMANCE; SURFACE; UNIT; FIN; TEMPERATURE; EXCHANGER; SYSTEM; GROWTH;

D O I：

10.1016/j.enbuild.2021.111695

中图分类号：

TU [建筑科学];

学科分类号：

0813 ;

摘要：

Many related studies suggested that a fixed airflow direction usually led to that the most frost would only deposit on the windward side of finned tube heat exchangers (FTHXs) of the traditional single fan outdoor coils in air source heat pumps (ASHPs), result in more frequent defrosting operations and a lower operating efficiency of ASHPs. In this experimental study, to achieve evener frosting on outdoor coils, a novel outdoor coil having two identical fans was proposed. The two fans, Fan A and Fan B, may operate alternately to reverse airflow direction based on a pre-set value of time interval for alternate operation (t(TI)(AO)). Feasibility and stability of the novel dual-fan outdoor coil to achieve even frosting on both windward and leeward sides of the FTHX were experimentally studied via seven experimental cases including both single and multiple frosting-defrosting operation cycles. The experimental results demonstrated that when using the novel dual-fan outdoor coil in Cases 3, 4 and 7, the heating/frosting duration was lengthened by 23.6%, 34.5% and 46.4%, and the averaged output heating capacity ((q) over bar) was increased by 5.5%, 9.5% and 9.6 %, and averaged COP (COP) by 6.7%, 10.5% and 11.1% respectively, and the defrosting frequency was decreased by 33.3% in Case 7,when compared to using the traditional single-fan outdoor coil. Besides, as t(TIAO) values were decreased from 15 mins to 10 mins for both fans, and to 6 mins for Fan A and 8 mins for Fan B, heating/frosting operation duration was increased by 8.9% and 19.4%, respectively, at a higher (q) over bar and C (O) over barP , as compared to those using the traditional single-fan outdoor coil. The experimental results clearly demonstrated that the use of the novel dual-fan outdoor coil can help achieve evener frosting on both sides of the FTHX, and hence a longer heating operation duration and a higher operating efficiency and output heating capacity. (C) 2021 Elsevier B.V. All rights reserved.

引用

页数：14

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