The lotus type porous copper heat sink has a higher heat transfer capacity as compared to micro channel heat sink for same size. Many studies on this heat sink show that its heat transfer capacity can be further improved by improving design of heat sink. This study investigates the heat transfer and flow characteristics of porous heat sink with different designs of internal bifurcations under both laminar & turbulent flow and studies the effect of such bifurcations on heat transfer of heat sink. The results of heat sink with bifurcations are compared with that of heat sink without bifurcations which show that for case of both laminar & turbulent flow, the heat sink with bifurcation showed better thermal performance as compared to heat sink without bifurcations.

Traditional air conditioning systems use a significant amount of energy on dehumidification by condensing water vapor out from the air. Membrane-based air conditioning systems help overcome this problem by avoiding condensation and treating the sensible and latent loads separately, using membranes that allow water vapor transport, but not air (nitrogen and oxygen). In this work, a computational fluid dynamics (CFD) model has been developed to predict the heat and mass transfer and concentration polarization performance of a novel active membrane-based energy exchanger (AMX). The novel design is the first of its kind to integrate both vapor removal via membranes and air cooling into one device. The heat transfer results from the CFD simulations are compared with common empirical correlations for similar geometries. The performance of the AMX is studied over a broad range of operating conditions using the compared CFD model. The results show that strong tradeoffs result in optimal values for the channel length (0.6–0.8 m) and the ratio of coil diameter to channel height (~0.5). Water vapor transport is best if the flow is just past the turbulence transition around 3000–5000 Reynolds number. These trends hold over a range of conditions and dimensions.

An improvement in performance of hybrid solar system with use of liquid metal alloy GaInSn as a coolant has been demonstrated in this study. The performance of hybrid system using GaInSn, water, and air as coolants under different operating conditions such as ambient temperature, different inlet velocities of fluid, solar irradiations is analyzed using simulation software ANSYS and the results obtained are validated using experiments. The results obtained from simulations and experiments are used for determining important performance criteria such as electrical efficiency, thermal efficiency, and exergy efficiency. The exergy, thermal, and electrical efficiencies were found to be at least 11%, 12%, and 12% higher for hybrid system using GaInSn as a coolant when compared to hybrid systems using air and water as coolants, respectively.