Adsorbent-Adsorbate Pairs for Solar Thermal Energy Storage in Residential Heating Applications: A Comparative Study

Abstract

This paper investigates the feasibility of using different adsorbent-adsorbate pairs in a thermal energy storage cycle to store solar energy for residential heating applications in Canada. Silica gel, activated carbon, activated aluminum, zeolite-4A, zeolite-5A and zeolite-13X adsorbents paired with methanol and water adsorbates are considered. Calculations are made to determine the volume, mass and cost of the adsorbent-adsorbate pair required to heat a house with four occupants. Zeolite 4A-water and zeolite 13X-water pairs are found to be the most economic (with an actual cost of 285 CAD and 374 CAD, respectively) and efficient (maximum heat of adsorption) adsorbent-adsorbate pairs with the minimum mass required, (290 kg and 226 kg, respectively) to meet the spatial heating requirements of the house.

An experimental comparison of thermal energy storage in directly and indirectly radiated adsorbent beds integrated with solar thermal collectors

“…Notably, when the adsorbate is water, zeolite 13X has a higher net heat of adsorption than other adsorbents such as silica gel, activated alumina, zeolite 4A, and zeolite 5A, which reduces the volume of adsorbent required for TES applications. 17 Furthermore, there have been numerous studies reported in the literature which show zeolite 13X yields good results in adsorbent-based TES systems. 18,19 More details regarding the zeolite 13X used in this work are provided in Table S1 in the supplementary information.…”

“…Furthermore, during the recharging phase water can be delivered to the zeolite 13X beads by passing air through the adsorbent bed; the water vapor in the air is adsorbed as air flows through the adsorbent bed. Notably, when the adsorbate is water, zeolite 13X has a higher net heat of adsorption than other adsorbents such as silica gel, activated alumina, zeolite 4A, and zeolite 5A, which reduces the volume of adsorbent required for TES applications 17 . Furthermore, there have been numerous studies reported in the literature which show zeolite 13X yields good results in adsorbent‐based TES systems 18,19 .…”