Results 111 to 120 of about 470 (129)
Some of the next articles are maybe not open access.
Applied Energy, 2012
Abstract When an air source heat pump (ASHP) unit operates in heating mode, frost can be accumulated on the surface of its finned outdoor coil which normally has multiple parallel circuits on its refrigerant side for minimized refrigerant pressure loss and enhanced heat transfer efficiency.
Shiming Simon Deng, Minglu Qu
exaly +2 more sources
Abstract When an air source heat pump (ASHP) unit operates in heating mode, frost can be accumulated on the surface of its finned outdoor coil which normally has multiple parallel circuits on its refrigerant side for minimized refrigerant pressure loss and enhanced heat transfer efficiency.
Shiming Simon Deng, Minglu Qu
exaly +2 more sources
Applied Energy, 2012
Abstract When an air source heat pump (ASHP) operates in heating mode, frost can be accumulated on the surface of its finned outdoor coil. Frosting deteriorates the operation and energy efficiency of the ASHP and periodic defrosting becomes necessary. Currently the most widely used standard defrosting method for ASHPs is reverse cycle defrost. On the
Minglu Qu +3 more
openaire +1 more source
Abstract When an air source heat pump (ASHP) operates in heating mode, frost can be accumulated on the surface of its finned outdoor coil. Frosting deteriorates the operation and energy efficiency of the ASHP and periodic defrosting becomes necessary. Currently the most widely used standard defrosting method for ASHPs is reverse cycle defrost. On the
Minglu Qu +3 more
openaire +1 more source
International Journal of Refrigeration, 1991
Abstract Many air source heat pumps use the reverse-cycle defrost to eliminate frost that forms on the outdoor heat exchanger during normal winter operation. During the defrost, the heat pump is switched from the heating to the cooling mode to provide heat to the outdoor heat exchanger to melt the frost.
Dennis L O'Neal +2 more
openaire +1 more source
Abstract Many air source heat pumps use the reverse-cycle defrost to eliminate frost that forms on the outdoor heat exchanger during normal winter operation. During the defrost, the heat pump is switched from the heating to the cooling mode to provide heat to the outdoor heat exchanger to melt the frost.
Dennis L O'Neal +2 more
openaire +1 more source
Central South University, 2011
To solve the fundamental problem of insufficient heat available during defrosting while ensuring the efficient and safe system operation for air-source heat pumps (ASHPs). A novel reverse-cycle defrosting (NRCD) method based on thermal energy storage to eliminate frost off the outdoor coil surface was developed.
Jian-kai Dong +3 more
exaly +2 more sources
To solve the fundamental problem of insufficient heat available during defrosting while ensuring the efficient and safe system operation for air-source heat pumps (ASHPs). A novel reverse-cycle defrosting (NRCD) method based on thermal energy storage to eliminate frost off the outdoor coil surface was developed.
Jian-kai Dong +3 more
exaly +2 more sources
Advanced Energy Systems, 1997
Abstract The heating seasonal performance factor (HSPF) of an air-source heat pump is degraded by the defrost cycle. Investigations have been performed previously which looked at active enhancement within the suction-line accumulator. This paper presents the results of a similar study with the use of passive enhancement techniques in ...
Terrance M. Roberts, Darin W. Nutter
openaire +1 more source
Abstract The heating seasonal performance factor (HSPF) of an air-source heat pump is degraded by the defrost cycle. Investigations have been performed previously which looked at active enhancement within the suction-line accumulator. This paper presents the results of a similar study with the use of passive enhancement techniques in ...
Terrance M. Roberts, Darin W. Nutter
openaire +1 more source
Renewable Energy, 2020
Abstract Adopting thermal energy storage (TES) based reverse cycle defrosting (RCD) for cascade air source heat pumps (ASHPs) is a feasible way to tackle the defrosting problem when the cascade ASHP is operated in heating process. However, during TES-based RCD, the phase change material (PCM) undergoes multi-mode heat discharging process, resulting ...
Qu Minglu +6 more
openaire +1 more source
Abstract Adopting thermal energy storage (TES) based reverse cycle defrosting (RCD) for cascade air source heat pumps (ASHPs) is a feasible way to tackle the defrosting problem when the cascade ASHP is operated in heating process. However, during TES-based RCD, the phase change material (PCM) undergoes multi-mode heat discharging process, resulting ...
Qu Minglu +6 more
openaire +1 more source
Applied Thermal Engineering, 2014
Abstract A previous related study has indicated that for an air source heat pump (ASHP) unit having a vertically installed multi-circuit outdoor coil, during reverse cycle defrosting, downwards flowing of melted frost over the outdoor coil surface could affect the defrosting performance, without however giving a detailed quantitative analysis ...
Mengjie Song +3 more
openaire +1 more source
Abstract A previous related study has indicated that for an air source heat pump (ASHP) unit having a vertically installed multi-circuit outdoor coil, during reverse cycle defrosting, downwards flowing of melted frost over the outdoor coil surface could affect the defrosting performance, without however giving a detailed quantitative analysis ...
Mengjie Song +3 more
openaire +1 more source
Applied Thermal Engineering, 2017
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 ...
Song, Mengjie FYTGS +4 more
openaire +3 more sources
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 ...
Song, Mengjie FYTGS +4 more
openaire +3 more sources
Building Services Engineering Research and Technology, 2011
When an air source heat pump (ASHP) unit is used for space heating at a low ambient temperature in winter, frost may be formed on its outdoor coil surface. Over time, frost accumulation on coil surface may become sufficient to restrict air passage through the coil and increase the heat transfer resistance between ambient air and coil surface, leading ...
Dong Jiankai +4 more
openaire +1 more source
When an air source heat pump (ASHP) unit is used for space heating at a low ambient temperature in winter, frost may be formed on its outdoor coil surface. Over time, frost accumulation on coil surface may become sufficient to restrict air passage through the coil and increase the heat transfer resistance between ambient air and coil surface, leading ...
Dong Jiankai +4 more
openaire +1 more source