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

在这个项目中，我们建议对水/氧化铝纳米流体在太阳能集热器微通道换热器中的强化换热应用进行数值模拟。当今国际社会面临的主要问题之一是降低能源(热电)产生的温室气体(GHG)排放水平。在制热过程中，可再生能源是最大限度地减少对环境的影响和降低排放水平的关键。太阳能热能技术目前提供高达80%的太阳能到热能的转换效率，这使太阳能热能技术处于主导未来可再生热市场的地位。为了满足对创新太阳能热系统的需求，Solar Tomorrow Inc.开发了一种基于专利微通道技术的新型建筑集成太阳能集热器。收藏家达到了很高的水平 高效，并无缝集成到建筑物的围护结构中。该项目的主要目标是通过最大限度地提高微通道换热器液区内的换热，进一步提高微通道太阳能集热器的效率，从而提高整个太阳能热系统的效率和产热量。这种改进可以通过使用纳米流体来实现。纳米流体是指含有一种或多种纳米颗粒的基础流体材料。通常，纳米流体中使用的纳米粒子是由金属、碳化物、碳纳米管或氧化物组成的，金属纳米流体由于其热物理性质可以增强流体领域的换热。增加纳米颗粒的体积分数或浓度可能会导致液态区域内的换热增加，直到某个体积分数取决于太阳能集热器的尺寸和平均温度为止。 是增加微通道内换热的纳米颗粒的最佳体积分数

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