Increased Efficiency of Photovoltaic Module via Groundwater Cooling: Energy and Economic Considerations

Solar energy will be an important source of energy for a sustainable energy system whether or not it is directly collected (solar thermal, photovoltaics) or indirectly collected (wind, wave, etc). This project focused on increasing the efficiency of the direct conversion of solar energy into electricity, which is also known as photovoltaics (PV). It has long been known that photovoltaic cells perform less efficiently at higher temperatures. In fact, solar modules under concentration are frequently cooled either actively or passively. The current study, however, focused on cooling modules under no concentration. The goal of the current project was to answer the question: Can the energy gained by cooling a photovoltaic module with groundwater be greater than the energy used by the cooling system and is there an economic benefit? A digital simulation of a simple photovoltaic module under groundwater cooling was performed in order to answer the research question. The simulation was performed for Phoenix, AZ and assuming certain control parameters it was found that the overall system produced over 9% more electricity than a system without groundwater cooling. While the groundwater cooled system increased overall electrical production, the economics of the system will also be presented. Recently, an Arizona utility APS introduced time of use pricing for electricity. Because groundwater cooling provides the most benefit during very hot days with high electrical demand, cooling is more economically attractive. A simple economic analysis will be presented including estimated costs of the cooling system and added value of the excess electrical energy produced under different APS rate plans.