3D Thermal Analysis of  Passive Cooling  Methods of PV Panels

This is a team project contributed by Hari Bharadwaj Narayanan, Anand Tripathi, Yi-Chen Chen and Mingjun Li.

Research Background

•Photovoltaic modules experience reduced efficiency in high-temperature environments. 

•We aim to optimize the heatsink design for better heat dissipation.

Method

• We use the central difference method to approximate the 3D steady-state heat conduction equation

• Analyze the result in different conditions

Assumptions for the Analysis 

•Radiation heat flux [W/m^2]= 800

•Panel material is primarily glass.

•Solar irradiance is constant. 

•Ambient temperature varies with time. 

•Convection coefficient is constant. 

•Radiation emitted from the panel is negligible 

In this study, the heat transfer has been discretized using the central difference method, which involves averaging the temperature of the surrounding nodes to find the temperature of the node under consideration. The actual discretization of each node varies depending on the location and the boundary conditions. 

To be exact, in this study, 50 unique nodes (8 surfaces, 23 edges, 18 corners and one interior node) were identified in the domain and appropriately discretized.  

Result and Analysis

The main output result, the interface temperture, was used to assess the fin performance. The study varied fin thickness, thermal conductivity and ambient tempertures to identify optimal configurations for minimizing interface temperature.  

From the result, we noticed that the lower the thermal conductivity, the greater is the fin length (beyond the interface (0.02 m)) where temperature variance can be seen. Besides, a more noticeable effect was observed at fin thermal conductivity =10 W/m·K, indicating some sensitivity to thickness in this range.

By varying the ambient temperture, we found that the greater the ambient temperature, the greater the interface temperature. 

Please feel free to read the report attached below for more detail.

The central‐difference method is a finite‐difference scheme for estimating derivatives that combines forward and backward differences via Taylor‐series expansions. By taking the average of these two approximations, we eliminate the leading error terms, resulting in a more accurate estimate of the derivative.

This method is different from CFD. In this model, the temperature field inside the solid is obtained by solving the Laplace equation using the central difference method, where temperature is approximated at discrete grid points and boundary conditions are applied explicitly.

In CFD, the governing conservation equations are integrated over each control volume. The finite volume method ensures local conservation of mass, momentum, and energy, allowing the flow field and heat transfer to be solved simultaneously. 

It is worth noting that even when the thermal conductivity is increased by two orders of magnitude, the reduction in fin temperature is less than 10 °C. This suggests that solid conduction is no longer the limiting factor, and the air-side convection resistance dominates the overall thermal resistance. Under the same environmental conditions, improving cooling performance therefore relies more on increasing the effective heat transfer area, such as by adding more fins or increasing fin height.