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) metho...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. Comparative experiments using both the stand reverse cycle defrosting (SRCD) method and the NRCD method were carried out on an experimental ASHP unit with a nominal 2.5 kW heating capacity. The results indicate that during defrosting operation, using the NRCD method improves discharge and suction pressures by 0.24 MPa and 0.19 MPa, respectively, shortens defrosting duration by 60%, and reduces the defrosting energy consumption by 48.1% in the experimental environment, compared with those by the use of SRCD method. Therefore, using the NRCD method can shorten the defrosting duration, improve the indoor thermal comfort, and reduce the defrosting energy consumption in defrosting.展开更多
DAR （diffusion absorption refrigeration） cycle is driven by heat and has no moving parts. It is based on refrigerant and absorbent as the working fluid together with hydrogen as an auxiliary inert gas. To circulate ...DAR （diffusion absorption refrigeration） cycle is driven by heat and has no moving parts. It is based on refrigerant and absorbent as the working fluid together with hydrogen as an auxiliary inert gas. To circulate the working fluid without a mechanical pump, the diffusion absorption cycle relies on a bubble pump. Experimental system was designed and operated. Its aim was to investigate the performance of a bubble pump operating with three lifting tubes. The experimental results of the system were compared to existing models. The comparison showed that there was a bad agreement between the experimental and the theoretical results.展开更多
The disturbance, caused by the boiling Phenomena in the inverted meniscus ac evaporator, is of great importancein the normal operation of the CPL, especially When the heat load is low. By theoretical and experimental ...The disturbance, caused by the boiling Phenomena in the inverted meniscus ac evaporator, is of great importancein the normal operation of the CPL, especially When the heat load is low. By theoretical and experimental studies onthis issue, it shows that the evaporator of the CPL operates in a mode of boiling in the Wick. By solving a set ofmomentum equations, it concludes that, this kind of boiling Phenomena in the wick cause no notable negativeinfluence on the normal peiformance of the CPL, although there really edests some adVerse influence during theCPL start-up. Addihonally, the causes of the dry-out of the evaporator under low heat load are conducted in thepaper. The conclusions are verified by subsequent experiments. More details about the experiments are alsodescribed in the paper.展开更多
基金Project(50606007) supported by the National Natural Science Foundation of China
文摘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. Comparative experiments using both the stand reverse cycle defrosting (SRCD) method and the NRCD method were carried out on an experimental ASHP unit with a nominal 2.5 kW heating capacity. The results indicate that during defrosting operation, using the NRCD method improves discharge and suction pressures by 0.24 MPa and 0.19 MPa, respectively, shortens defrosting duration by 60%, and reduces the defrosting energy consumption by 48.1% in the experimental environment, compared with those by the use of SRCD method. Therefore, using the NRCD method can shorten the defrosting duration, improve the indoor thermal comfort, and reduce the defrosting energy consumption in defrosting.
文摘DAR （diffusion absorption refrigeration） cycle is driven by heat and has no moving parts. It is based on refrigerant and absorbent as the working fluid together with hydrogen as an auxiliary inert gas. To circulate the working fluid without a mechanical pump, the diffusion absorption cycle relies on a bubble pump. Experimental system was designed and operated. Its aim was to investigate the performance of a bubble pump operating with three lifting tubes. The experimental results of the system were compared to existing models. The comparison showed that there was a bad agreement between the experimental and the theoretical results.
文摘The disturbance, caused by the boiling Phenomena in the inverted meniscus ac evaporator, is of great importancein the normal operation of the CPL, especially When the heat load is low. By theoretical and experimental studies onthis issue, it shows that the evaporator of the CPL operates in a mode of boiling in the Wick. By solving a set ofmomentum equations, it concludes that, this kind of boiling Phenomena in the wick cause no notable negativeinfluence on the normal peiformance of the CPL, although there really edests some adVerse influence during theCPL start-up. Addihonally, the causes of the dry-out of the evaporator under low heat load are conducted in thepaper. The conclusions are verified by subsequent experiments. More details about the experiments are alsodescribed in the paper.
