Computational multiphase iterative solution procedure for thermal performance investigation of phase change material embedded parallel flow solar air heater

Abstract

In this numerical work, we present a computational multiphase iterative solution procedure for thermal performance investigation of PCM embedded parallel flow solar air heater. This study comprehensively addressed the possibilities of obtaining thermal back using PCM under double air flow arrangement. Therefore, heat flux (600≤I≤·1000W/m2) and flow parameter i.e. total mass flow rate (0.01≤(M˙=m˙1+m˙2)≤0.05kg/s) is considered for the present investigation and thermal performance of the collector design is compared for three air flow cases, viz. i) when equal mass flow rate is maintained in both duct (m˙1=m˙2=M˙/2), ii) when high mass flow rate (m˙2)is maintained in the upper duct and relatively low mass flow rate is maintained in the lower channel (m˙1<m˙2), and iii) when low mass flow rate (m˙2)is maintained in the upper duct and relatively high mass flow rate is maintained in the lower channel (m˙1>m˙2) The present mathematical modelling involves an iterative solution procedure using MATLAB code, which is capable of predicting components and flowing air temperatures. Steady state energy balance for each component and flowing fluid is performed to obtain boundary conditions. However, unsteady diffusion and convection form of the energy equation are solved for each component and air flow pass, respectively, to present temperature distribution. Finite volume method is applied to solve the developed unsteady governing differential (energy) equations and the convergence criterion of 10–6 is considered. The maximum thermal performance of 64.1% is obtained when total mass flow rate is 0.05 kg/s. Moreover, the obtained temperature contours are delineated in order to understand the related physics.