A renewable energy based air conditioning system for buildings with high comfort requirements

A geothermal desiccant assisted air conditioning system and a dynamically controllable geothermal heat exchanger are investigated. Experimental results of both systems are presented and discussed. The investigated air conditioning system is capable of limiting the electrical energy demand to auxiliary energies. A reduction of 76 % compared to a conventional system is achieved. The energy demand is shifted from electricity to thermal energy required to regenerate the desiccant material. The investigated system requires 2.4 times more thermal energy which can be supplied by solar energy. However, occurring peak loads remain a weak point of the system. Air injecting borehole heat exchangers, which create an artificial groundwater flow, are a promising option to overcome this problem. Numerical and experimental investigations show that the performance can be improved by a factor of 2.5. For peak loads a performance increase by factor 5 is realistic underlining the potential of the borehole heat exchangers to be used in an air conditioning process.