Implicit Equation for Photovoltaic Module Temperature and Efficiency via Heat Transfer Computational Model

Abstract

This paper evaluates the photovoltaic (PV) module operating temperature’s relation to efficiency via a numerical heat transfer model. The literature reports that higher PV module operating temperatures impact PV module efficiency. There are dozens of explicit and implicit equations used to determine the PV module operating temperature. However, they are not universal, and for each application, it is necessary to insert a correction coefficient based on the environment and boundary conditions. Using a numerical method covering a more comprehensive range of PV module operation conditions to estimate a global equation, this study considers the solar radiation flux, Gt, solar ray direction with respect to the ground level, γ, convective heat transfer coefficient, h, tilt angle, β, ambient temperature, Ta, PV power output, Ppv, PV panel efficiency, η, and environmental properties. The results match the extant empirical work and related literature. PV module efficiency is found to have a linear relationship to the PV module operating temperature via a numerical heat transfer model corresponding to the well-known PV module. It specifies that heat transfer convection changes with PV module tilt angle, causing PV module operating temperature effects. It also represents the PV module operating temperature variations with ambient temperature and solar flux, like those reported in the literature.

Temperature Field Measurement of Photovoltaic Module Based on Fiber Bragg Grating Sensor Array

“…In pure natural convection, the flow intensity caused by buoyancy can be expressed by the Rayleigh number . In outdoor environments, when the operating temperature of the photovoltaic module placed at an angle of 30~80° is 30~100 °C, [ 33 ]. In this case, the buoyancy-driven convection is in the transition stage between laminar flow and turbulent flow, and the temperature field changes near the surface of the photovoltaic module are very complex at this stage.…”

Wind Velocity and Forced Heat Transfer Model for Photovoltaic Module

“…The conversion of solar energy into electricity within a photovoltaic (PV) panel depends on various factors related to the module's properties and its surrounding environment [1,2]. A significant portion of the incoming solar energy is dissipated within the panel as heat.…”

“…In a stable operating state, the primary means of heat dissipation from the panel's surface to the surrounding environment are radiation and convection [3,4]. To accurately determine the surface temperature of a photovoltaic module in a steady-state energy balance [1,5], the following essential data must be considered:…”

“…Gathering and appropriately utilizing these data points are vital steps in predicting the surface temperature of a photovoltaic module in a state of steady energy equilibrium. In the realm of heat transfer coefficients, various empirical relationships have been suggested to characterize heat transfer due to wind, offering satisfactory outcomes under specific circumstances [1,6]. In this context, T C represents the temperature utilized for forecasting the electrical performance of the module.…”

“…The temperature of PV modules is significantly influenced by environmental factors, and wind speed plays a crucial role in heat transfer through convection [1,3,6]. Typically, wind speed is assumed to have a cooling effect [1].…”