Characteristics of MEMS Heat Sink Using Serpentine Microchannel for Thermal Management of Concentrated Photovoltaic Cells

This work explains the simulation-based study to understand the thermohydraulic characteristics (thermal resistance and pumping power) of a MEMS heat sink using serpentine microchannels employed for thermal management of concentrated photovoltaic cells; the planar dimensions of both are 1 cm by 1 cm. In this study, water is the coolant and the MEMS heat sink is constructed in silicon. Over the Reynolds number varying from 50 to 1000 and for concentration ratio of 20, the thermal resistance and pumping power of a MEMS heat sink using serpentine microchannel, in comparison with that using straight microchannel, is lower and higher, respectively; the benefit of switching microchannels outweigh the cost as up to 64% reduction in thermal resistance is achieved with just 126% rise in pumping power. Studies are done for understanding the contribution of geometry of the serpentine microchannel on the characteristics of the MEMS heat sink. Irrespective of the geometry, rise in Reynolds number leads to the rise and decrease in the pumping power and thermal resistance, respectively. For a particular Reynolds number, decrease in hydraulic diameter, rise in offset width, and decrease in offset length led to rise in pumping power and decrease in thermal resistance. The contribution of concentration ratio on characteristics of MEMS heat sink using serpentine microchannel is investigated and found to be independent of concentration ratio. Nusselt and Poiseuille numbers of serpentine microchannel are provided for the benefit of heat sink designers; these parameters are higher for serpentine microchannel in comparison with a similar straight microchannel.