A novel design for solar collector used for water heating application having nanofluid as working medium: CFD modeling and simulation

Abstract

A solar collector is a simple and cheap device that is capable of collecting and converting solar radiation into useful heat energy. The thermal performance of the solar collectors can be enhanced significantly with the suspension of nanoparticles in the base fluid. A novel design for a solarassisted water heater (SWH) is proposed in the current study and the effect of nanofluid has been investigated on the thermal efficiency of the SWH. The use of nanofluid is one of the prominent methods in comparison to other techniques for improving the performance of solar collectors and therefore, the base working fluid i.e. water is mixed with the alumina nanoparticles of average particle size of 30 nm, and they are assumed to be spherical. The flow and thermal characteristics of nanofluid through the solar water heater are simulated numerically with the help of the Eulerian-Eulerian two-phase model using the finite volume method (FVM). The commercial package i.e. ANSYS Fluent is used for modeling the problem under transient conditions with a pressure-based solver. In comparison to a conventional flat plate collector, the proposed solar water heater consists corrugated absorber-plate and the effect of radius of curvature of corrugation has been investigated on the heat transfer and collector efficiency. With the proposed design the heat transfer area available with the riser tubes increases remarkably and it leads to a 43% and 14% increase in heat transfer augmentation and collector efficiency, in comparison to the conventional solar water heater.