Nowadays, technologies are changing rapidly and enhancing human life by providing alternative solutions, global communications, fastest information transfers, comfortability and eases. All human life sectors are fundamentally based on technology development, including the energy sector. In the energy sector, technology can address the environmental issues and depletion of fossil fuels which is dominant in human life. These technologies have born among us such as solar photovoltaic, wind turbine, biofuel, fuel cell and so on and so forth until the new one which is remained under research to be commercialized is PV/T (photovoltaic thermal).
Before PV/T born, the researcher has tried to develop PV and also Solar Thermal System in separated researches. PV panel is one of technology that can harness the light energy to generate the electricity power by collecting its radiation on one semiconducting panel. PV panel works by absorbing photons (bundle of light energy) and exciting them to the higher energy level so the electrons in semiconductor materials move more easily (across the junction) producing the voltage and DC currents later. Semiconducting materials are multifarious and abundant in our earth, such as silicon (amorphous, monocrystalline, polycrystalline, thin silicon film), cadmium telluride (CdTe), Copper-Indium-Gallium-Selenide (CIGS) or organic materials (dye-sensitized). In another hand, Solar Thermal System is a system that harnesses the thermal energy from the sun to generate the heat or electricity by using thermal-conductive materials and conductive fluids (water or refrigerants or others). This technology works by heating the conductive material (generally, the geometry is piping) with the sunlight and this material will be heated and transfer the heats to the fluids in it and flow through the pipeline to be harnessed directly or generate the electricity.
Nowadays, researchers not only try to improve the solar cell efficiencies but also innovating the PV and thermal system to be one system namely PV/T technology. PV/T comprises common PV panel coupled by the thermal system (on the back of the PV panel) to generate electricity together as one system. This can generate more electricity in one identic area. This can address the issue of low efficiency in PV panel or thermal as a standalone system and the issue of land use problem (costly and complicated).
PV/T has three types namely air based PV/T, concentrated and liquid-based PV/T within categorized by three kinds of liquids like water, refrigerants and hybrid water/air. PV/T within the air is the most practical and can be done with minimum operational cost, while water-based PV/T is more efficient one rather than air-based PV/T based on their thermo-physical properties.
PV/T has developed well over 25 years. National Renewable Energy Laboratory (NREL) has developed PV/T well established and prominently all over the world. In the ASEAN region, there is a Solar Energy Research Institute (SERI) who tries to develop PV/T as one of the answers for agricultural industries issues. Both institutes would like to build the most efficient PV/T systems from materials, fluids, geometrical, devices, and appropriate thermal insulator. Not technically only, NREL tries to develop how to conduct the training, installation, commissioning and management of PV/T system if it will be commercialized in the near future. By their research, all countries will wish good PV/T commercial as a better renewable energy tool which is affordable and easy-to-use for all.