Thermal And Hydraulic Performance Of A Novel Evaporator Coil For Refrigeration Systems

With increasing energy cost and constraints on emission standards, there is a strong need to reduce energy consumption and/or increase equipment efficiency. Refrigeration systems are the third largest use of electricity globally, consuming 1.8 trillion kWh annually. There have been some recent developments in energy efficient refrigeration systems, driven by rising price of electricity and increasing environmental concerns. However, refrigeration equipment remains highly energy demanding. One of the key sources of high energy consumption is the need to periodically heat up the system to defrost the evaporator coils. To solve this problem and reduces the energy demand of the defrosting system, a new evaporator coil is designed which can be defrosted at a fraction of the required energy. The new coil is a finless spiral-helical coil that uses a patented defrost/de-icing technology. In this paper, experimental investigations are presented that compares the thermal and hydraulic performances of a conventional finned-tube coil with a finless coil for a small cooling capacity unit. An experimental setup is designed and built to measure the cooling capacity and air pressure drop of both finned-tube and finless evaporator coils. The results show a higher cooling capacity per surface area for the new finless coil than the finned-tube one and that is mainly due to its higher heat transfer coefficient; making it suitable for this application.