DESICCANT COOLING TECHNOLOGY POWERED BY SOLAR THERMAL AIR COLLECTOR SYSTEMS

摘要

Two large desiccant cooling units powered by 100 m² solar air collector fields were designed and implemented in a public library building in Spain and a production hall in Germany. The systems differ in the sorption wheel technology used (silicagel matrix and LiCl sorption wheel) and in the auxiliary energy supply source, which is an auxiliary heater in the German and an auxiliary cooler in the Spanish case. In both systems it could be shown that only temperature measurements are reliable performance indicators and that the dehumidification potential in commercial units has to be derived from temperature measurements. For the enthalpy changes during the drying process, laboratory measurements were carried out on smaller commercial desiccant wheels in Stuttgart and optimum rotation speeds and volume flow ratios were determined. rnThe monitoring results from the Spanish desiccant cooling plant are part of the building management system and complete datasets are only available for short periods in 2002. Together with detailed measurements on the plant they could be used for short term performance evaluation and COP´s of 0.5-0.6 were obtained at regeneration temperatures of 70°C. For the German system a whole summer period has been analysed. The mean COP of the desiccant cooling system was 0.95. If only the full desiccant operation is considered, the COP drops to 0.5. An interesting fact is that a significant part of the heating energy was provided at exterior temperatures below 25°C, where the desiccant process is very energy intensive.