An open sorption heat storage concept and materials for building heat supply

Zettl, B. (Speaker)

Activity: Talk or presentationOral presentation

Description

Sorption heat stores, which utilize adsorption heat released during hydration processes, have got the potential to be realized as loss free seasonal heat storages to supply hot water and heating for households. The possibility to store solar energy in summer und use thermal energy in winter is a key technology to reach high solar fractions in heat supply of domestic buildings compared to conventional solar thermal applications. Recent studies (2-4) have examined the possibilities and restrictions of such storage concepts using synthetic zeolites. Further development seems necessary since these materials need high desorption temperatures quite above the temperatures provided by conventional solar thermal collectors. Even if the costs for zeolite based storage concepts have not reached market acceptance yet, much additional efforts are made to improve the systems and to utilize new and more economic storage materials. In order to overcome material performance problems of salt impregnated structures, new process concepts have been developed. An open sorption drum-reactor, as described in literature (1), was used for characterization of several sorption materials. In contrast to fixed bed reactions a moved bed can avoid over-hydration in the gas entrance area and control of reaction is easy and swift compared to large vessel-reactors. Over-hydration, sticking, incoherent melting, thermolysis and other material related problems have been identified in connection salt-impregnated structures. Characteristics of the adsorption reaction were analysed (see Fig 1&2) at different operation temperature levels and moisture contents of the inlet-airstream. With the use of an appropriate sensoring system characteristics of the process are determined. Since the airstream is used as moisture transfer medium and thermal transfer at the same time special requirements for material permeability results. Several materials have been measured and the results are compared in terms of heat storage capacity, temperature shift, required air moisture, desorption behaviour and durability.
Period9 Mar 2015
Event title9th International Renewable Energy Storage Conference IRES: null
Event typeWorkshop
LocationDüsseldorf, Germany