Paper presented to the 3rd Southern African Solar Energy Conference, South Africa, 11-13 May, 2015.
Two natural zeolitic tuffs of different European origin were studied for thermal adsorption storage application and as possible additives in plaster. The water adsorption behavior and the thermal adsorption storage properties were checked by thermoanalysis and in a lab-scaled storage of 1.5 L volume. The storage capacities achieve about half of the capacities of synthetic zeolites. The mixing properties in standard plaster showed to be very suitable for use. From our thermoanalytical results we estimated for an additive content of 20 wt.% thermal effects of 30-50 kJ/kg plaster. The thermal effect of Micronal® in plaster amounts to 20 kJ/kg plaster if the possible concentration of 10 wt.% is taken into account. Thus, the zeolitic tuff have a better thermal effect than the BASF product Micronal® containing an organic phase change material (PCM) as active component.