Heat Transfer and Pressure Drop Characteristics of a Liquid Cooled Manifold-Microgroove Condenser
High performance condensers are essential components in energy conversion, electronics cooling and process systems. Increased capacity and functionality with less and less available space has been a main driving force for development of next generation of condensers in energy systems. Our previous work in this area has demonstrated that manifold-microgroove heat exchangers operating in single-phase or two-phase modes offer substantially higher heat transfer performance with a greatly reduced pumping power when compared to state-of-art microchannel heat exchangers. The goal is to enhance heat transfer while minimizing the pumping power, volume and weight. A compact lightweight manifold microgroove condenser, with 60 × 600 micron microgrooves and cooling capacity of 4kW, was fabricated, assembled and tested using different manifolds. Experiments using R236fa and R134a as a working fluids were performed measuring inlet and outlet temperatures, flow rates and pressure drops for the refrigerant and water side. Overall heat transfer coefficient and pressure drop across condenser were determined and refrigerant side heat transfer coefficient were calculated based on water side heat transfer coefficient. Experimental results indicate significant effect of manifold geometry on condenser performances. Refrigerant side heat transfer coefficient of 60 kW/m2K with pressure drop of just 7 kPa has been demonstrated using R-134-a.