Advanced liquid cooling for concentrated photovoltaic electro-thermal co-generation

Abstract

We demonstrate an advanced packaging approach with an embedded silicon micro-channel water cooler wliere the photovoltaic cell is electrically connected by a metallization on the silicon sustrate. The backside of the silicon substrate contains the micro-machined fluidic channels thereby minimizing the thermal resistance compared to a state - of- the - an package. This leads to a reduced temperature drop between the photovoltaic cell and the coolant, allowing an increase in the temperature of recovered heat. A low-pressure drop split-flow fluid manifold is implemented to distribute the coolant from one single input to the micro-channel array and back from two outlet pons. A thermal resistance of 0.12 cm 2KW was demonstrated, which allows for the removal of 100W/cm 3 heat (>1000 suns) at a △T of I2K. Direct chip attacited silicon coolers enable higher overall concentration factor thereby reducing photovoltaic cell cost. An additional benefit of silicon is its inertness against corrosion and the matching thermal expansion coefficient which allows building of systems with a very long lifetime. The split flow configuration reduces pumping power to about 5% of the system photovoltaic output. More complex manifold micro-channel systems are proposed to minimize the pumping power to a level below 1% and to cool arrays of cells on a single large substrate.