A Three-Dimensional Comprehensive Numerical Investigation of Different Operating Parameters on the Performance of a Photovoltaic Thermal System With Pancake Collector

Abstract

Performance of photovoltaic (PV) module decreases significantly with increasing cell temperature due to its overheating. Photovoltaic thermal (PVT) is an optimized technology that facilitates effective removal and utilization of this excess heat leading to enhanced electrical performance. In this article, a 3D numerical model has been developed and analyzed to investigate the PVT performance with a new pancake-shaped flow channel design. This flow channel is attached directly to the backside of PV module by using thermal paste. The governing equations are solved numerically by using Galerkin's weighted residual finite-element method (FEM), which has been developed using COMSOL Multiphysics® software. The numerical results show that the cell temperature reduces on an average 42 °C, and the electrical efficiency and output power increase by 2% and 20 W, respectively, for both aluminum and copper channels with an increase in inlet velocity from 0.0009 to 0.05 m/s. On the other hand, overall efficiency of the PVT system drops about 13% in both cases as the inlet temperature increases from 20 °C to 40 °C. Cell temperature is found to increase approximately by 5.4 °C and 9.2 °C for every 100 W/m2 increase in irradiation level of the PV module with and without cooling system, respectively. Regarding flow channel material, it has been observed that use of either copper or aluminum produces almost similar performance of the PVT module.

Effect of nanofluids on heat transfer and cooling system of the photovoltaic/thermal performance

“…The governing equations of PVT system are given below (Nasrin et al , 2018a, 2018b, 2018c; Sardarabadi and Passandideh-Fard, 2016; Nahar et al , 2017; Fayaz et al , 2018): where:…”

“…The boundary conditions are as follows (Nasrin et al , 2018a, 2018b, 2018c; Nahar et al , 2017; Fayaz et al , 2018): at all solid boundaries of the fluid passing path: no-slip condition u = v = w = 0; at the solid-fluid interface inside heat exchanger: knftrue(∂T∂ntrue)nf=khetrue(∂T∂ntrue)he; at the inlet boundary of the fluid passing path: T = T in , u = 0, v = V in , w = 0; and at the outlet boundary: convective boundary condition p = 0. …”

“…The amount of total received energy by the solar cell, output electrical power and collected thermal energy (Nasrin et al , 2018a, 2018b, 2018c; Nahar et al , 2017; Fayaz et al , 2018) from the PVT system are calculated by the following equations respectively: and …”

“…The instantaneous electrical, thermal and overall efficiencies (Nasrin et al , 2018a, 2018b, 2018c; Nahar et al , 2017; Fayaz et al , 2018) of the PVT system are: …”

“…In addition, this numerical code is used to get the solar cell temperature of PVT system operated by water. The values of cell temperature against the inlet water temperature at T amb = 27°C, G = 1,000 W/m 2 , V in = 0.005 m/s is compared with that of Nahar et al (2017) and is shown in Table V. The authors used polycrystalline silicon PV panel (1,570 × 940 mm) of five layers, 6*10 number of cells, pancake format fluid flow pipe design with aluminum metal, length of pipe of 8.5 m, inner radius of pipe of 0.012 m, packing factor of 0.95, glass transmitivity of 0.9, cell absorptivity of 0.9 and reference efficiency of PV 11 per cent.…”