Hybrid photovoltaic-thermic system with enhanced cell energy efficiency

Abstract

Interest towards green energy has been increasing over the past decades, due to the increasing effect climate change and unsustainable energy sources pose to the planet. Among the renewable energy sources only solar, hydropower and wind provide substantial potential, while geothermal, wave energy, and biomass provide a local solution.
Solar energy has the potential of being one of the world’s largest energy providers, due to the fact it is present in every corner of the earth and can be converted with ease into electric energy and thermal energy using photovoltaic(PV) and solar panels.
Hybrid systems generate significant quantities of electricity and also generate heat. Photovoltaic-Thermal(PVT) systems have the potential to reduce the energy consumption in buildings, reducing both thermal and electrical energy, thus reducing the operation costs.
This study aims to design, model, and test the energy efficiency of a PVT system to overcome the main drawbacks of photovoltaic panels.
The main challenge photovoltaic panels face is overheating which leads to a reduction in the cells efficiency and energy production, overcoming this is through cooling and recovering the excess heat with the cooling agent. At the same time using the recovered thermal energy to supply the needs of the building in terms of heating and hot water, either directly or as a preheated primary agent, a further reduction in terms of the building energy requirements is achieved.
This study analyses the performance and efficiency of three original design hybrid photovoltaic systems using water as a cooling agent.
Through cooling a photovoltaic panel with a cooling agent with various flow rates, the efficiency of the photovoltaic cells is maximized, and through keeping their temperature as close to the nominal operating cell temperature (NOCT), the study aims to prevent degradation through overheating and cooling cycles during the day and night.
Through cooling a PV panel with water as a coolant, the efficiency of the photovoltaic cells is increasing from 17.85 in the case of the uncooled panel to over 19% in the case of the water-cooled systems at a flow rate of v = 3 l/min and v = 5 l/min.