An Irish research team developed a PVT system consisting of a 170 W photovoltaic panel connected to a water tank placed on the back of the PV module itself. The PVT module is able to significantly reduce the temperature of the PV unit while producing hot water for residential use.
The group said its PVT water collector is an attractive option to boost overall solar panel performance, as the storage tank acts as a typical gas-fired geyser used to produce hot water for domestic use.
“In general, gas-fired geysers are widely used in Pakistan to heat water for daily use, and in recent years, Pakistan has faced the problem of gas overload, which makes hot water production in winter crucial,” it explained, noting that the proposed PVT solution represents a carbon-free solution for hot water supply. “Water from the upper reservoir is flown by gravity, heated in a geyser and then used in households.”
The system consists of a 170 W solar panel connected to a water tank placed on the back of the solar module itself. The size of the storage tank is 150 cm x 66 cm x 4 cm and it is made of wood covered with aluminum sheet to prevent the wood from decaying due to water.
“The PV module circuit was saved by using a rubber seal to prevent water from coming into contact with it,” the researchers explained. “Two top ends, one for the inlet and one for the outlet, were included. Five steel rods were bolted to the back of the wooden plate to support the structure.
The team compared the performance of the PVT module to a reference electrical panel without a water tank. It found that the PVT panel ensured high heat transfer between the PV surface and the tank, which was able to significantly lower the operating temperature of the PV unit. According to the team’s calculations, the power output of the PVT panel was 19% higher than the pure PV equivalent.
“Furthermore, the hybrid PVT module was able to produce hot water, which was considered an added benefit,” the researchers noted, noting that the PVT panel uses about 50.04 percent of the incoming solar radiation, while PV only uses 11.4 percent. “So it can be concluded that hybrid PVT can be used efficiently to produce both electrical energy and hot water from one system.”
They presented the system in the journal “Energy and Stress Analysis of a Photovoltaic Hybrid Thermal Module”, published recently Thermal engineering case studies.
An international research team led by Imperial College London recently conducted a comprehensive review of all solar thermal systems designs developed so far, both at the research and industrial level.