Malaysian researchers have developed a system that can absorb heat from PV modules and transmit it to a nanofluid, in order to transform it into thermal energy and use it for different applications. The panels have an overall efficiency of 89%.
Image: Universiti Kebangsaan Malaysia
Researchers at Universiti Kebangsaan Malaysia have fabricated a photovoltaic-thermal (PVT) system that uses a cooling nanofluid circulation system with a phase change material (PCM). The system can absorb heat from the PV panels and transmit it to the nanofluid, where it can be transformed into thermal energy and used for different applications. The Malaysian group said their work uses micro-fins copper tubes for the first time, in order to enhance the thermal conductivity of the PCM.
PCM can absorb, store and release large amounts of latent heat over defined temperature ranges. They have often been used at the research level for PV module cooling and the storage of heat.
The scientists built the system with a 30 W solar module measuring 640 mm x 360 mm x 25 mm. They used a 9.52 mm pipe, which they soldered to the panel with copper tape and pure copper. They also used a PCM container filled with 2.75 kg of nano PCM, a heat exchanger, and a PCM expansion tank.
“The operational fluid from the reservoir is pushed through the PVT by a pump,” they explained. “In order to keep the entryway’s temperature stable, the working fluid loses heat from the PVT by passing through a heat exchanger connected with the cooling unit.”
The scientists tested the systems under different illumination conditions and a room temperature of 27 C, with the working fluid temperature set at 20 C, controlled by a water-cooling chiller. The temperature of the cooled PV panel fell from 86.2 C to 42.1 C, which pushed its overall efficiency to 89%.
“The thermal and electrical energy of a PVT system utilizing Nano PCM and Nanofluids in a Micro fins tube is more than that of any other system studied,” the researchers said, without providing data on system costs.
The researchers presented the system in “Experimental analysis for the photovoltaic thermal collector (PVT) with nano PCM and micro-fins tube nanofluid,” which was recently published in Case Studies in Thermal Engineering. In recent years, the group has also developed multi-level fin heat sinks for solar module cooling, as well as lapping and longitudinal fins.
