The effect of temperature glide on the performance of refrigeration systems.

Many currently used refrigerants are potent greenhouse gases and therefore need to be replaced with lower global warming potential (GWP) fluids. The list of the proposed replacements includes a significant amount of refrigerant mixtures that exhibit large temperature glides during the phase change. The use of such refrigerants will affect the temperature distribution in evaporator and condenser and thus impact a refrigerating system behavior. The current work analyses the effect of refrigerant glide on the performance of refrigeration systems. The discussion is supported with experimental observations of two different refrigeration systems at different operating conditions. The results suggest that refrigerant glide have significant effect on performance of systems through means of temperature glide matching, refrigerant composition variation and heat transfer coefficient degradation. This effect differs depending on the refrigeration system design, type of evaporator/condenser and thermodynamic properties of refrigerant. Attending to the experimental results of the study, it is concluded that the possible advantages of temperature glide are not utilized at the conditions of drop-in replacements.