Bionic micro porous evaporation foil for photovoltaic cell cooling

A novel cooling system for photovoltaic (PV) cells on the basis of a bionic evaporation foil is demonstrated. A prototype version of the foil is presented which has been realized by a two-layered dry film resist. The foil is laminated directly on silicon substrates providing good thermal contact with the water cooled down by evaporation. In this work the fabrication of the evaporation foil is shown as well as the cooling capabilities with respect to environmental temperature, pore density, structure heights, etc. The bionic evaporation foil provides cooling performance equivalent to the state of the art of today's PV-systems. A temperature reduction up to 11.7 degrees C is proved with perspective to further significant enhancement. The presented system is capable of self-regulating the water flow and the resulting cooling rate by its direct dependency on environmental conditions like temperature and air velocity. (C) 2014 Elsevier B.V. All rights reserved.