The idea of combining both types of technology into a combined solar collector for heating a pair of water / air heat transfer agents arose from the need for high utilization of energy gains from solar radiation throughout the year and maximizing the operating time of the solar system.
The combined solar collector using two heat transfer substances is in principle based on a situation typical of a temperate and cold climate zone. In it, the level of solar radiation in summer is sufficient for the preparation of hot water (50 - 60 ° C), while in winter the outlet temperatures from solar collectors usually do not reach values higher than 30 ° C. However, they may still be sufficient, eg for heating cold ventilation air.
Based on the data obtained during testing, experts from UCEEB performed a year-round simulation analysis. Its results confirmed the possibility of increasing heat gains from solar systems by up to 20% when using combined solar collectors.