PERFORMANCE ANALYSIS OF HEAT EXCHANGER FOR COOLING APPLICATIONS UNDER DRY AND WET CONDITIONS

The present study is carried out to compare evaporator coil's performance for dry and wet conditions. Numerical simulations are performed by solving a set of governing equations for the above-mentioned operating conditions (dry and wet). Two typical fin configurations, named plain and corrugated or wavy fins, for the staggered tube arrangements are studied. The model utilizes the conservation equations of mass, momentum, and energy to the physical domain. Only a two-phase condition for the flow within the evaporator tube is considered. The working fluid considered for cooling in the heat exchanger is R134a. Variation of evaporator coil performance for different operating parameters such as air inlet temperature, air inlet relative humidity, refrigerant inlet temperature, and mass flow rates of refrigerant and air is presented in this study. The analysis is performed by solving the sets of equations in a MATLAB environment. It is worth observing that the value rises when the relative humidity, air mass flow rate, and air inlet temperature increase. The values are increased by about 7% and 12% from the dry working condition to the wet working condition for plain and wavy fin configurations, respectively. With increase in refrigerant mass flow rate and evaporation temperature, the UA value increases but it is not as much significant as air mass flow rate and air inlet temperature. The air-side pressure drop is increased by 30% for a wavy fin as compared to a plain fin.