WEB Adsorption heat storage and transformation: Towards harmonization of an adsorbent and a cycleThursday (24.09.2020) 10:10 - 10:40 P: Processing and Synthesis 1 Part of:
Adsorption heat storage and transformation (AHST) is considered as an alternative to common compression and absorption machines. Although several adsorption chillers have already appeared in the market, there is still big room to improve their performance and reduce size. In this lecture, we consider the role of adsorbent in AHST and discuss which adsorbent properties are optimal for various AHST cycles. This approach is based on the assumption that for each specific adsorption cycle, there is an optimal adsorbent which properties would allow a harmonization just with this cycle. To create an image of such an idealized adsorbent, we take into consideration both thermo-dynamic and dynamic requirements. Conclusions are formulated in terms of the optimal isobar (isotherm) shape and the adsorption uptake. We use the Dubinin-Polanyi adsorption potential F as a quantitative measure of the affinity between the adsorbent and the adsorptive. At the same time, for many working pairs, the F-value also determines borders of AHST cycle.
For discovering adsorbents promising for AHST, it is worthy of following two complementary lines:
a) screening of adsorbents that had been initially developed for other applications (gas drying, separation, etc.). Indeed, booming progress in the materials science offers a huge choice of novel porous solids which might be used for AHST. We give here an overview of several classes of materials that are potentially promising for this emerging application. Among them are metal-organic frameworks, porous carbons, aluminophosphates, composite "salt in porous host matrix" and others. Developing a database of adsorbents promising for AHST, which is in great demand, is discussed;
b) intent synthesis (tailoring) of new specific adsorbents harmonized with various AHST cycles under different climatic conditions. Particular examples of the target-oriented design of the re-quired adsorption properties are given for selected adsorbents of water, methanol, and ammonia.
New advanced adsorbents harmonized with particular AHST cycles are prerequisite for a major breakthrough in adsorptive cooling/heating/storage, and therefore, are pivotal for this challenging application.