A coupling method using CFD, radiative models and a surface model to simulate the micro-climate

Sammanfattning: The increasing demand for energy, depletion of fossil fuels, rising global warming, and greenhouse gas emissions have stimulated the need for widespread development and adoption of renewable energy sources (RES) worldwide. Among these sources, solar energy has emerged as a major contender to meet the growing demand. It offers adaptable applications and provides an alternative to traditional energy sources. A brand-new application of solar panels is agrivoltaics. Agrivoltaics consists in installing solar panels above farming lands such as crops. The combination of solar energy production and farming on the same lands increases the overall yield of the land and brings several other opportunities. However, agrivoltaics is also very challenging. An improper installation of solar panels above crops may result in a dramatic drop of the farming yield. Thus, it is of major importance to understand how to maximize the solar energy production without harming the plants or decrease the farming yield. This master’s thesis focuses on the impact of agrivoltaic systems on the micro-climate close to the crop. The goal is to link the modified physical phenomena within an agrivoltaic system and their impact on the crops. The methodology is based on Computational Fluid Dynamics (CFD). The idea is to realize high fidelity simulations of the different physical phenomena and their coupling, and compare them to experimental data. Flow simulations coupled with radiative models and a surface model are realized in this perspective. The master’s thesis is divided in three parts. 1. Based on experimental data collected during three years at the EDF lab les Renardières, determine which physical phenomena impact the most the crop and what are the key parameters to study the growth of the plants. 2. Validate with experimental data from the atmospheric laboratory the SIRTA (Site Instrumental de Recherche par Télédétection Atmosphérique) of the engineering school Polytechnique, the radiative models and the surface model of the CFD software. 3. Study the impact of an agrivoltaic system on the identified physical phenomena with a simple geometry composed of one pitch of solar panel. The data study shows clearly that the plant temperature, the groundwater, and the radiation play crucial roles in the growth of the plant. A lack of radiation or groundwater will limit the growth of the crops. In addition, extreme temperatures can harm the crops. Consequently, this research project will firstly focus on capturing the impact of the solar panels on these three key parameters. Simulations are using a coupling of a 1D radiative model which is computationally fast and that can therefore be applied on a very large domain to compute the absorption of the atmospheric layers and the clouds, and a 3D radiative model which is able to capture the impact of an obstacle such as a solar panel. This coupling is validated for the shortwave radiation and the longwave radiation. Finally, full U-RANS simulations with the radiative models, the surface model and the - turbulence model are realized. The impact of the panels on the radiation field, the soil temperature, the specific humidity and on other fields such as the wind speed is well captured.