Experimental research on hot liquid defrosting system with multiple evaporators

•A new type of defrost method named as Hot Liquid Defrosting System with Multiple Evaporators for cold storage (HLME) was proposed.•The system can continuously refrigerate during defrosting without increasing additional power consumption.•Although it is in defrosting, the HLME system refrigeration performance is still desirable. It is universally acknowledged that the growth of frost layer will deteriorate the performance of refrigeration system in cold storage. Seeking efficient and rapid defrosting methods is a common concern in academic. This study presents a new type of defrosting method named as Hot Liquid Defrosting System with Multiple Evaporators (HLME) for cold storage. Multiple evaporators are installed in different refrigeration rooms in HLME system. When one of them needs to be defrosted, hot liquid refrigerant out of condenser is first used to remove the frost layer of the fins with achieving liquid refrigerant sub-cooled at the same time. The system can continuously refrigerate during defrosting without increasing additional power consumption. To further study the refrigeration system working performance, an experimental apparatus of this system was developed. A tested room with artificial load was constructed and the refrigeration performance of the system has been experimentally investigated in the process of frosting and defrosting, which mainly included the variation of the vapour suction, discharge pressure and temperature of the compressor, the liquid refrigerant temperature, the sub-cooler heat exchange, refrigeration capacity and refrigeration COPc.