Solar-thermal panel overcomes problem of stagnation
Viessman’s Vitosol200-FM solar-thermal flat panel ends the problem of overheating and stagnation with the use of ThermProtect, a patented ‘intelligent’ absorber layer that, through temperature-dependent change in its crystal structures, adjusts automatically to changes in sunlight and heat absorption.
Traditional flat-panel solar-thermal collectors can be prone to steam production due to stagnation, which in turn leads to degradation of the heat-transfer medium. This can be an issue in spring or summer when excess heat from the Sun cannot always be used and the panel temperature rises. ThermProtect rejects the excess heat back to the environment.
Above an absorber temperature of 75°C, the coating increases its emitting of incoming solar radiation and, in effect, shuts down. When the temperature of the collector falls below 75°C, the structure of the coating will return to its original state, and 95% of the incoming solar energy is absorbed and converted into heat.