Development of a sorption assisted air conditioning system driven by a solar air collector

Depending on climate and humidity up to 80% of primary energy consumption of HVAC system must be spent for dehumidification of ambient air to achieve conditions of comfort in the room. This large amount is caused by the condensation process, including the cooling down of the air flow below dew point. At the same time, following state of the art, the air has to be warmed up after this step again. The dehumidification can be performed more energy efficient by using sorption technologies. Due to this background, an open system based on a sorptive coated cross-flow heat exchanger of ECOS-type in combination with an evacuated tube solar air collector as heat source is developed within the collaborative project "SorLuko" of Fraunhofer ISE and companies airwasol and Contherm. The development is including a complete re-design of all components, starting with the aluminum heat exchanger, layout of the collector for providing high temperature, and a new developed coating technique. For attesting the improvement of the new components as well as functional proof of the concept, a demonstration system has been built up at airwasol facility. The dehumidification and cooling application makes use of an adsorptive coating in one channel of the cross-flow heat exchanger (HX) of ECOS type, while the cooling of the supply air can be achieved by indirect evaporative cooling generated by saturation of the waste air with water sprayers in the second channel.