Study on heat transfer and cold storage characteristics of a falling film type of cold energy regenerator with PCM

The heat transfer and cold storage characteristics of a falling film type of cold energy regenerator were numerically and experimentally studied in cold energy storage process. Combined with falling film heat transfer and cold storage technology with solid-liquid phase change material, the test system was made up of three columns of horizontal tubes and each column vertically contained 36 copper tubes. Hydrophilic coating was sprayed on the outside surface of copper tubes to reduce the solid-liquid contact angle. The heat transfer fluid was water and the film Reynolds number range of liquid film was from 100 to 500. A mixture of decanoic acid, lauric acid and oleic acid was adopted as the PCM whose phase change temperature is around 20 °C. Study results show that the cold energy regenerator has good heat transfer performance and cold storage characteristics with small pumping power consumed. Lower film Reynolds number will strengthen the cold storage performance. At the same time, flexible cold storage quantity can be simply obtained through adjusting the column or row number of the tube bundle. The present study proposes a good choice for cold energy storage unit.