Versatile siloxane based adsorbent coatings for fast water adsorption processes in thermally driven chillers and heat pumps

• We report a versatile silicone based coating procedure.
• Various samples with coating thickness between 130 and 290 μm were achieved.
• We measured very fast rise up times between 24 s and 29 s.
• The hydrothermal stability has been proven over 3000 cycles.
• The coating procedure is inexpensive and environmental benign.

In this work a versatile and hydrothermally stable binder based coating with fast adsorption kinetics for the use in thermally driven adsorption chillers, heat pumps and within dehumidification processes is reported. Two different adsorbents, a SAPO-34 with a typical adsorption isotherm favorable for low desorption temperatures and a zeolite Y for higher desorption temperatures were used. The coatings were prepared out of an aqueous dispersion for different binder contents with a minimum of 2.5 wt%. The performance of the coating and the influence of the binder on the equilibrium and dynamic adsorption characteristics were evaluated by means of thermogravimetry and a volumetric pressure jump method. Finally the hydrothermal stability under typical application boundary conditions was evaluated with surprisingly fair stability even for a very low binder content of a 2.5 wt%.