Heat Transfer Measurements for an Evaporator Plate Discussion of Hysteresis and Ice Formation Phenomena

Paper in proceeding, 2002

The aim of this paper is to investigate ice formation and the possible occurrence of hysteresis phenomenon in a plate-type evaporator, used in for example district heating heat pumps. Detailed heat transfer and pressure drop measurements are carried out for both pure fluids and zeotropic mixtures. Experimental results, together with some simulation results, are used to discuss the ice formation phenomenon. One result is that the refrigerant temperature at start of ice formation differs between refrigerants, especially between pure fluids and mixtures. The evaporator duty is observed to depend on start-up conditions. An explanation based on a boiling hysteresis phenomenon is suggested.