Solar Water Heating Systems (SWHS) are the most widely used type of Solar Heating and Cooling Systems. These systems pass cold water through a pipe that goes into a heat exchanger. From the exchanger, solar collectors carry heat transfer fluid, which is heated from the incoming infrared radiation from the sun. Then, it is the heated fluid what warms up the stored water that is used to heat or cool homes.
Solar thermal heating and cooling is a well-known and still evolving technology. Among recent developments, it is the innovation of the district solar heating network in Denmark, showing optimized performance. Further development is performed to achieve advanced solar energy collectors.
Two main types of solar collectors are currently in the market: unglazed and glazed (flat plate and evacuated tubes). Glazing is preferable as collector’s efficiency can be further improved by adding transparent insulation materials to the collector’s surface, allowing in this way the reduction of heat losses between the panel and the environment. The newest development can be found in new designs like thermoplastic natural rubber tubing on absorber plates with foam insulation and water as the working fluid. Through this combination, 72% efficiency and 65ºC tank temperature can be reached. Other benefits are the low manufacturing costs, the high performance and the high durability.
Further developments are focused on the heat transfer fluid, looking for fluids with low freezing point in cold climates and high boiling point in hot climates. These properties together with others like viscosity, and thermal capacity play a key role in the overall performance of the system. Some examples of fluids that are being analysed are the air, oils, hydro-carbon, glycol/water mix, refrigerants, etc.
Earth Observation can be used to determine the right location for the installation of heating system. Satellite data and its modelling allow to foresee the irradiation and hence to choose the site with the potentially highest irradiation. Depending on the infrastructure, satellite images can be also used to monitor its efficiency and condition.
Main stakeholders doing R&D: Ibersolar Energía, Solaris Energía Solar, Osiel S.L., Giacomo & Cidete Technologies
Main stakeholders in the market: Zytech, Acpsol Energia Solar, Arpi Solar Systems, Energy Panel, Kom Sol International World Wide Distribution, Novasol Sistemas Energéticos, Promasol Energía Solar