Ngo, Lloyd ChabalaBello-Ochende, TundeMeyer, Josua P.2016-10-112016-06Lloyd Chabala Ngo, Tunde Bello-Ochende & Josua Meyer (2016) Numerical investigation of natural convection of cavity receiver for low power application, International Journal of Green Energy, 13:8, 845-851, DOI: 10.1080/15435075.2016.11616281543-5075 (print)1543-5083 (online)10.1080/15435075.2016.1161628http://hdl.handle.net/2263/57095A parabolic dish/cavity receiver configuration is one of the solar thermal systems used for light-heat conversion at high temperature. Such systems are subject to continuous changes in ambient conditions such as wind, solar insolation, and ambient temperature. These environmental variations, as well as changes in receiver inclination angle, affect the overall receiver performance leading to energy loss. Natural convection contributes a significant fraction of the energy loss and hence a thorough understanding of its characteristics is essential to effectively minimize it in order to improve the system efficiency. A three-dimensional numerical investigation was conducted on a modified cavity receiver to quantify the convective components of the total heat loss and to determine the effects of the operating temperature, receiver inclination angle, and aperture size on the heat loss. The effects of the variation of air properties were accounted for by using polynomial relationships for density, specific heat capacity at constant pressure, dynamic viscosity, and thermal conductivity in the simulation. The calculated natural convection heat loss showed a nonlinear dependence on the inclination angle and aperture size. Visualization results such as temperature contours were also presented to gain an insight into the effects of natural convection.en© 2016 Taylor and Francis Group, LLC. This is an electronic version of an article published in International Journal of Green Energy, vol. 13, no. 8, pp. 845-851, 2016. doi : 10.1080/15435075.2016.1161628. International Journal of Green Energy is available online at : http://www.tandfonline.comloi/ljge20.Cavity receiverNatural convectionNusselt numberParabolic dishEngineering, built environment and information technology articles SDG-07SDG-07: Affordable and clean energyEngineering, built environment and information technology articles SDG-09SDG-09: Industry, innovation and infrastructureEngineering, built environment and information technology articles SDG-13SDG-13: Climate actionPostprint Article