Effects of Greenhouse Building Materials on the Energy Consumption of Cold Climate Solar Greenhouses
Traditional agricultural and farming practices demand significant energy, exacerbating overreliance on fossil fuels that drive climate change. With this growing issue, the implementation of “agrivoltaics” – the dual use of land for agriculture and photovoltaic (solar) energy production – has become increasingly relevant. One interesting agrivoltaic system is a greenhouse that could be fully powered by solar cells, which would increase viable land for agricultural use without increasing demand for fossil fuels. In this work, we aim to determine the impact of various greenhouse building materials on the greenhouse’s energy efficiency and annual crop yield. Our previous work showed that agrivoltaic greenhouses in northern, colder climates (specifically Minneapolis) suffer from significant heating demands. We hypothesize that building materials with larger thermal resistance will reduce greenhouse heating demands. Using a MATLAB model, we simulated the energy usage and plant growth of an agrivoltaic greenhouse with a roof coated with luminescent nanoparticles surrounded by a grid of photovoltaic cells. By retrieving thermal properties, emissivity, and light transmission data from the literature of commercially used plastics and glasses, we varied the materials properties of the greenhouse walls and roof to understand the optimal material that minimizes energy demand without compromising plant growth. We determined that using a “Hortiplus” glass can reduce heating demands by 25 percent while reducing lettuce yield by just ten percent; this glass maintained visible light transmission while decreasing emissivity through a tin oxide coating. Future work will explore the balance between crop yield and energy demand in additional climates.