Numerical simulation on application of water/Al2O3 nanofluid in heat transfer enhancement in microchannel heat exchanger of solar collectors developed by Solar Tomorrow Inc

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In this ENGAGE project, we propose to numerically model the application of water/Al2O3 nanofluid in heat transfer enhancement in a microchannel heat exchanger used in solar thermal collectors. One of the main problems that the international community faces today is lowering the level of greenhouse gas (GHG) emissions caused by energy generation (both heat and electricity). Renewable energy sources are the key to minimizing environmental impact and reducing emissions level during the heat generation process. Solar thermal technology currently offers efficiency of conversion of solar energy to heat in the range of up to 80% that places the solar thermal technology at the position to dominate the future market for renewable heat. To satisfy the need for innovative solar thermal systems Solar Tomorrow Inc. developed a new kind of building integrated solar thermal collectors based on a proprietary microchannel technology. The collectors achieve high efficiency and are seamlessly integrated into buildings' envelope. The main goal of this project is to further increase efficiency of the microchannel solar thermal collectors by maximizing the heat transfer in the liquid domain of the microchannel heat exchanger to improve the efficiency and heat generation from the entire solar thermal system. The improvement can be achieved by the use of nanofluid. Nanofluid is a terminology for a base fluid material containing one or more than one kinds of nanoparticles. Usually, the nanoparticles that are used in nanofluid are made of metals, carbides, carbon nanotubes or oxides.Metallic nanofluids may enhance the heat transfer in fluid domain because of the thermal physical properties of the nanoparticles. Increase in the volume fraction or concentration of nanoparticles may cause increase in the heat transfer in the liquid domain till a certain volume fraction Depends on the size and average temperature of the solar collectors there would be an optimized volume fraction of the nanoparticle that increases the heat transfer in the microchannel