The technical solution is a decentralised hot water boiler with two AC heating rods. The tenant can operate the first heating rod with an output of two kilowatts himself: He can set the desired temperature on the thermostat. He has no access to the second heating rod, which also has an output of two kilowatts, because this is reserved for solar power use.
See also: Electric heating mat for new and old buildings
It is controlled by a timer so that from March to September between 10 a.m. and 2 p.m. it uses surplus solar power to heat water. It heats the drinking and shower water to 70 degrees. Only when the temperature in the boiler drops to 50 degrees does the first heating element switch on. The residents thus need significantly less expensive electricity from the public grid. (mfo)
Also interesting: My-PV triples production space for solar electric heating systems
