New type of energy efficient heat exchanger for indirectly cooled display cabinets. Laboratory and fields tests.

In this study, a completely new type of air-to-liquid heat exchanger, adapted for obtaining good heat transfer performance even at a laminar flow regime on the liquid side has been evaluated in a display cabinet application. The heat exchanger consists of parallel plates, with liquid in every second passage and air in the other passages. Tests were performed with a traditional open vertical display cabinet, first with a traditional finned-tube coil and thereafter with the new type of heat exchanger, both in a climate chamber and thereafter in the field. The results from both tests showed that the liquid inlet temperature could be increased by around 6°C, from the range -8°C - - 7°C with the traditional coil to the range -2°C - - 1°C with the new type of heat exchanger, which can lead to considerable energy savings and operation without the need for defrosting of the heat exchanger.