Progetto HYCOOL - D4.5 Evaluation of long-term behaviour and possible degradation of the materials in the adsorption chiller - RE-65/24

The aim of this report is to allow a better estimation of the life time of the adsorber materials within adsorption heat pumps, highlight possible degradation mechanisms and present adapted testing procedures for their identifications as well as mitigation strategies for the prevention or reversal of the material ageing. Two different types of ageing were tested for. At CNR ITAE, accelerated cyclic ageing test was performed whereas at Empa on-shelf ageing was investigated for several adsorbent materials (SAPO- 34 from Fahrenheit, Siogel from Oker and RMF activated carbon from Empa). While the stability of all sorbents was good under operational cycling, storage conditions need to be chosen carefully in order to conserve the adsorption characteristics of all materials. Namely long-term storage should not be performed under humid condition. An accelerated testing procedure was developed to test for possible ageing under humid storage conditions. In general, the manufacturers and operators of adsorption chillers are encouraged to perform such tests in order to identify potential weak points in the system and prevent additional maintenance. As mitigation measures, degassing of the chiller before down time, storage or shipping has been highlighted.