SUSTAINABLE HEATING AND COOLING WITH SOLAR-POWERED DIFFUSION – ABSORPTION TECHNIQUE WITH EARTH HEAT EXCHANGERS
Earth heat exchangers in combination with reversible electrical heat pumps are regularly used for air-conditioning of recent low-energy buildings. At the University of Applied Sciences in Stuttgart, the exchange of the electrical heat pump by a thermal powered diffusion-absorption machine with a nominal cooling power of 3.5 kW and heating power of 7.5 kW is investigated. The driving energy is supplied by solar power, in the wintertime assisted by an auxiliary heater. Two earth heat exchangers with a length of 80 m each can be used for direct cooling of the building during summertime as well as for removal of heat from the condenser / absorber of the machine. During wintertime this energy can be retracted from the ground for heating purposes. The projected saving of primary energy is 56%.