Numerical and Parametric Analysis for Enhancing Performances of Water Photovoltaic/Thermal System

Photovoltaic/thermal (PV/T) systems are innovative cogeneration systems that ensure the cooling of photovoltaic (PV) backside and simultaneous production of electricity and heat. However, an effective cooling of the PV back is still a challenge that affects electrical and thermal performance of the PV/T system. In the present work, a PV/T numerical model is developed to simulate the heat flux based on energy balance implemented in MATLAB software. The numerical model is validated through the comparison of the three-layer PV model with the NOCT model and tested under the operation conditions of continental temperate climate. Moreover, the effect of velocity and water film thickness as important flow parameters on heat exchange and PV/T production is numerically investigated. Results revealed that the PV model is in good agreement with the NOCT one. An efficient heat transfer is obtained while increasing the velocity and water film thickness with optimal values of 0.035 m/s and 7 mm, respectively, at an inlet temperature of 20 °C. The PV/T system ensures a maximum thermal power of 1334.5 W and electrical power of 316.56 W (258.8 W for the PV). Finally, the comparison between the PV and PV/T system under real weather conditions showed the advantage of using the PV/T.

Improving The Efficiency of Photovoltaic Cells by Using the Distilled Water Immersion Method

Photovoltaic panels can convert solar irradiance into (electrical and thermal) energy. The (PV / T) system was developed, created, and its performance tested in this experimental analysis. The main objective of this study was to design, manufacture and evaluate the work of the PV/T system as a thermal collector to enhance heat transfer, by using distilled water as a working fluid used to cool (PV/T) system. The experiment was performed with flow rate of water from (1 L / min to 5 L / min) on the PV / T collector channel. A theoretical and practical study was conducted on the effect of cooling the panels by immersing (PV) from (upper and lower) in a distilled water parallel flow forced circulation. Numerical result obtained by using Comsol Multiphysics program have been used as a computational fluid dynamic (CFD). The numerical study was conducted to determine the optimal depth of immersion of the panel to experiment with it, simulation results showed that the optimum depth of immersion is (5mm). The experimental results were conducted at the Technical Engineering College of Najaf with indoor test conditions that were controlled, Tin=20 °C, h=5mm. The results have been shown that the electrical efficiency of traditional photovolatic panel without cooling varied between (10.5-11.6) %, while the electrical efficiency of PV/T system varied between (14.6-14.7) %.

4E Advancement of Heat Recovery during Hot Seasons for a Building Integrated Photovoltaic Thermal (BIPV/T) System

In conventional building integrated photovoltaic thermal (BIPV/T) systems, heat is only recovered during cold seasons. However, no recovery takes place in hot seasons. Therefore, this study comes up with an answer to the question “how much improvement in the amount of annual recovered heat (ANRH), average exergy efficiency (AAEE), and CO2 saving (ACDS), as well as payback period (PBP), is achieved when heat recovery is done in hot seasons?”. These are representatives of energy, exergy, environmental and economic (4E) aspects, respectively. The results show a 135.6%, 1.8% and 123.0% enhancement in the ANRH, AAEE and ACDS, respectively, while PBP decreases from 6.10 to 3.94 years.