Modern houses often have a heat pump heating system and a ventilation system with heat recovery. This combination uses ambient heat and reduces the building’s energy requirements. Adding sufficient insulation allows building operation that is almost greenhouse-gas neutral. This invention from the Aachen University of Applied Sciences, a thermoelectric exhaust-air heat pump, builds on this principle. It uses thermoelectric elements to extract heat energy from exhaust air and transfers it to the supply air. Several thermoelectric elements are inserted between the supply air and the exhaust air duct and arranged according to the countercurrent heat exchanger principle.

The invention can extract much more heat energy from exhaust air than heat recovery alone can manage. The supply air can also be heated beyond the exhaust air temperature with thermoelectric elements. Buildings with high energy efficiency classes therefore need no additional heat generation system and thus save space and money. The thermoelectric exhaust-air heat pump can also cool the building, making an air conditioning system unnecessary. The system is quiet and compact enough to be integrated into the facade.