Solar thermal - Facades

Solar thermal uses the heat of the sun's rays to heat a transfer fluid in solar collectors.

Solar thermal and solar electricity on roofs and facades are in competition for the surfaces.
Both techniques have advantages and disadvantages. These depend on the individual case. A few examples:

The warm water supply for a beach house (showering after swimming in the lake) can be completely covered with some thermal solar collectors. The warmer the weather is, the more people go swimming in the lake and the more frequently the shower shower is used. In bad weather, only little shower water is available, but as hardly anybody bathes in the lake the shower is hardly used. In winter, guests stay away. Perfect match between demand for hot water and hot water supply.

A group of homeowners operates a year-round storage with many solar panels on their roofs. The storage stores the sun's heat during the summer. This heat will be used in winter for heating. Apart from the storage loss the gained solar heat can be fully exploited.

A teacher couple does have a rather large solar collector system for water heating on their roof. The plant provides enough hot water for the period from March to October. In summer, the theoretically possible heat output can not be fully exploited because there is far more hot water than the owners are able to use for showering. Moreover, during summer the owners go away on holiday just when the plant would have its high season. For people who like to travel in summer, a photovoltaic system is often a better solution. With that, the electricity generated in summer is not lost. Instead, it will be fed into the public grid and be payed for by the grid operator.

For an office building where hardly any hot water is needed a solar thermal system is rather out of place anyway.