Liquid-gas heat exchanger for low pressure refrigerant application

Liquid-gas heat exchanger has been developed for subcooling-superheating process of vapor compression refrigeration cycle. Refrigeration cycle utilizes low pressure refrigerant, which facilitates in easy piping installation and spill-proof operation. Experimental and numerical studies have been performed in order to quantify and understand thermal-hydraulic behavior of subcooling-superheating (liquid-gas) heat exchanger. As a result of low pressure refrigerant application, low volumetric flow rate in liquid domain can result in dominant natural convection and thus, poor heat exchanging performance. Also, high volumetric flow rate of low pressure gas refrigerant can increase gas side pressure drop. Both phenomenon were observed in conventional shell and tube heat exchanger application and resulted in system COP (Coefficient of Performance) degradation. This paper deals with development of efficient heat exchanger providing high heat transfer, designed for specific application, composed of multiple-fin and microchannel tubes type heat exchanger installed in shell structure. CFD (Computational Fluid Dynamics) methods are used for design optimization; leading toward improved system performance along with size reduction in comparison to shell and tube heat exchanger.