Comparison of the Thermal Performance of a Solar Heating System with Open and Closed Solid Sorption Storage

TRNSYS simulations have been performed for each system concept using the properties of two different thermochemical storage materials (TCM). It is shown that the type of TCM has a significant influence on the systems fractional thermal energy savings. Using silica gel as TCM, both system concepts' performances are only slightly better compared to a standard water-filled storage tank of the same size. The TCM zeolite 13 XBF, a binder free 13 X zeolite, leads to significantly better fractional thermal energy savings. Although the two systems under investigation behave differently, the fractional thermal energy savings are similar. High solar thermal fractions up to a complete solar coverage can be achieved for both storage concepts with moderate collector array and store sizes.