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Korean scientists have proposed a simple method to transform existing photovoltaic systems into photovoltaic-thermal (PVT) systems. They claim the new design offers a cheaper alternative to expensive PVT systems, while allowing for easier and faster deployment.
Researchers at Pusan ??National University in South Korea have developed a hybrid photovoltaic-thermal rooftop system that can also be installed as a retrofit solution where a photovoltaic system is already operating.
The system uses attachable solar collectors (ASC) designed to be combined with photovoltaic panels and convert the latter into FVT modules on site without the need to dismantle them.
“Our PVT-ASC system is economically advantageous for small-scale buildings and those with photovoltaic panels already installed,” lead author of the research Sangmu Bae told pv magazine . “The ASC is lightweight and designed with on-site construction in mind. An installer can directly transport two or more ASCs.”
According to Bae, the PVT-ASC system can overcome the technical and economic limitations of current commercial PVT arrays, which require higher initial costs compared to conventional PV systems.
“In addition, the PVT-ACS is beneficial for the environment because the work process can be significantly reduced,” he also said. “If the photovoltaic panels are already installed on a building, disassembly and transportation work can be omitted.”
The researchers explained that the type of ASC used for the solution consists of a 1,800 mm × 910 mm rectangular shell, a 1,624 mm × 855 mm closed-loop heat exchanger inserted inside the shell. The collector must be fixed to the back of the photovoltaic panel with thermal grease and carbon steel tubes. “This simple manufacturing process can be applied to buildings without specialized construction knowledge,” they add.
The solution also includes a waterproof film applied to the parts of the ASC exposed to the outside environment, as well as the inlet and outlet connections of the heat exchanger, which, according to the academics, makes work easier during on-site installation.
They verified the configuration of the proposed system in a south-facing pilot array located in Gimhae-si (South Korea). The system consists of PVT-ASC panels, a heat accumulator, a circulation pump, thermocouples, a flowmeter, a pyranometer and a data logger.
Measurements showed that the assembly has a thermal efficiency in line with that of commercial PVT products. “The thermal efficiency of the PVT-ASC was reasonable, considering the simpler attachment method compared to the lamination and roll bonding methods of typical PVT modules,” the academics explain.
They also conducted an economic analysis that showed that the average standard price of the proposed system could be $280/m2, which would be 30%, or $120/m2, less than the standard price of PVT in Korea. They also explained that the total costs of the PVT-ASC system include disassembly, manufacturing, transportation and installation work that was saved compared to conventional PVT systems. This sum was estimated at $3,820.
The group presented the system in the article “ Development of photovoltaic-thermal using attachable solar collector based on on-site construction,” published in Applied Thermal Engineering . “The PVT-ASC presented in the research article is a prototype, so its initial investment cost is high. However, if production processes and facilities are built for marketing, the unit price can be reduced,” says Bae. |
