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Scientists in Malta have created an aftermarket cooling solution that can be installed on existing standard photovoltaic modules. The system is based on a water chamber placed on the back of the module and can reportedly provide a net electrical energy gain of over 9%.
A group of scientists from the University of Malta has developed an after-market cooling system for photovoltaic modules that uses a water chamber that can be placed in a recess on the back of standard modules.
“The Innovative Photovoltaic Cooling System (IPCoSy) has already been patented,” Luciano Mulè Stagno, corresponding author of the research, told pv magazine . “This invention can be advantageous for offshore or floating PV installations, due to unlimited water resources, and can also benefit both the residential and industrial sectors, which aim to install PV modules and operate them with greater efficiency.”
The system consists of a bottom plate that is hermetically fixed to the base protrusions of a solar module frame to create a water chamber directly beneath the back of the panel itself. “This water chamber is defined by the PV module backsheet, the frame wall, and the bottom plate,” the scientists explain. “Examples of suitable materials for the bottom plate include, but are not limited to, aluminum, stainless steel, polyethylene terephthalate (PET), polypropylene, and polyimide.”
The water chamber includes a water inlet and a water outlet arranged at opposite sites on the frame wall. A temperature sensor is fixed to the backsheet of the photovoltaic module and electrically connected to an external junction box. All these components are sealed with a waterproof material.
The system includes a jet spreader hydraulically connected to the inlet on the inner surface of the frame wall. “This jet spreader is configured to provide uniform fluid dynamics within the water chamber with the goal of expelling the hot water with as little mixing as possible,” the group explains. “The construction of the jet spreader involves an assembly of a T-elbow joint connected to the water inlet at one end and two 45-degree elbow joints connected to two other ends of the T-elbow joint, correspondingly.”
The proposed solution also includes a tube adapter that hydraulically attaches to the water outlet on the outer surface of the frame wall and is intended to facilitate panel installation. “The adapter can be rotated so that the water in the chamber is in contact with the backsheet of the PV module regardless of the installation angle, ensuring maximum heat transfer,” say the researchers, who note that the water is pumped into the cooling system using a water pump that can use seawater or water from a reservoir.
According to the research group, the proposed system can provide net electrical energy savings of more than 9%, and thermal efficiencies of up to 56%.
“The modified PV module incorporating the cooling system costs 9.7% more than current standard PV modules,” Mulè Stagno explained. “A PV system including the aftermarket cooling design in its current state will cost twice as much as current standard PV modules. However, these prices were calculated on “one-off” prototypes, so series production is expected to significantly reduce costs. Moreover, if thermal efficiencies due to water heating are taken into account and not just electrical efficiencies due to PV cooling, these prices already make sense.”
The new cooling technology was presented in the study “ Innovative Photovoltaic Cooling System ”, published in Innovation Disclosure. “This invention excels even more in areas where there is already a water flow for other processes, such as reverse osmosis plants,” the scientists stressed. “In these types of plants, IPCoSy modules will supply electrical energy from a renewable source while using the existing water flow to increase the operational efficiency of the photovoltaic modules.” |
