Please use this identifier to cite or link to this item: http://hdl.handle.net/10397/65728
Title: Experimental investigation on reverse cycle defrosting performance improvement for an ASHP unit by evenly adjusting the refrigerant distribution in its outdoor coil
Authors: Song, M
Liu, S
Deng, S 
Sun, Z
Yan, H
Keywords: Air source heat pump
Defrosting
Experimental study
Melted frost downwards flowing
Multi-circuit outdoor coil
Uneven refrigerant distribution
Issue Date: 2017
Publisher: Pergamon Press
Source: Applied thermal engineering, 2017, v. 114, p. 611-620 How to cite?
Journal: Applied thermal engineering 
Abstract: For an air source heat pump (ASHP) unit, reverse cycle defrosting operations are always conducted to solve the undesired frosting problem. Previous studies verified that, uneven refrigerant distribution (URD) and melted frost downwards flowing (MFDF) along the vertically installed multi-circuit outdoor coil would degrade system defrosting performance. However, it is hardly possible to separate the URD and MFDF effects in a practical multi-circuit outdoor coil. In addition, it is a fundamental coupled problem of uneven heat and mass transfer. Consequently, to investigate the coupled effects of MFDF and URD on system defrosting performance, a sequential experimental study is carried out and reported in this paper. Firstly, a special testing facility and tailor-made three-circuit outdoor coil were introduced. This is followed by two experimental cases designed, with frost evenly accumulated on the surface of each circuit by adjusting the stop valves’ opening degrees. After the experimental results compared, basing on refrigerant evenly and unevenly distributed into each circuit, energy analysis was also given. Finally, as concluded, the coupled effects were negative on system energy performance, and defrosting efficiency increased by 7.4%, from 40.5% to 47.9%, when the refrigerant's distribution changed from uneven to even. This study makes contributions on the optimization of system control strategies.
URI: http://hdl.handle.net/10397/65728
ISSN: 1359-4311
EISSN: 1873-5606
DOI: 10.1016/j.applthermaleng.2016.11.206
Appears in Collections:Journal/Magazine Article

Access
View full-text via PolyU eLinks SFX Query
Show full item record

SCOPUSTM   
Citations

4
Citations as of Aug 11, 2017

Page view(s)

15
Last Week
5
Last month
Checked on Aug 13, 2017

Google ScholarTM

Check

Altmetric



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.