Hydraulic and Thermal Engineering Calculation in the Laminar Mode of Operation of a Photoelectric Thermal Battary

Abstract

Efficient conversion of solar energy into electrical and thermal energy has become a major goal of researchers around the world. In this regard, the authors have developed photovoltaic thermal installations to efficiently convert solar energy into electricity and heat. This article briefly analyses the development of a photovoltaic thermal system for efficient cooling of the photovoltaic part with various methods and coolants. A photovoltaic thermal battery (PTB) with a cooling system based on multichannel polycarbonate has been developed. The dimensions of the cellular polycarbonate channels are 7 x 12 mm2. Water flows horizontally through more than 200 channels in parallel streams. The thickness of the cellular polycarbonate sheet is 4 mm. The PTB cooling system is a structure consisting of a sheet of cellular polycarbonate and channel openings, which are attached to two perpendicularly located polypropylene tubes using transparent silicone sealant. This design of the cooling system (absorber) has less weight and a lower cost compared to traditional metal structures, and the cellular polycarbonate sheet in the PTB is protected from direct exposure to ultraviolet radiation emitted by the sun. The model of a combined PTB installation based on a "photovoltaic battery and heat converter" (PVB-TC) was implemented using COMSOL Multiphysics 5.6. Hydraulic and thermal calculations were carried out in laminar mode, and PTB parameters were determined: water temperature at the outlet of the absorber PTB , water pressure at the inlet of the absorber , and water flow G at the corresponding water velocities W=0.1 m/s, 0.2 m/s, and 0.3 m/s, taking into account three values of ambient temperature - 25 °C, 35 °C, and 45 °C. The modelling process took into account the use of concentrated solar radiation in a combined PEP-TEP installation using weakly concentrating reflectors.

Keywords

• hydrodynamic calculation
• comsol multiphysics 5.6
• photovoltaic thermal battery
• cooling methods
• model
• thermal analysis
• water velocity
• water flow
• water temperature
• pressure
• environment