SORPTION THERMAL ENERGY STORAGE SYSTEMS WITH EMBEDDED MEMBRANES FOR IMPROVED POWER DENSITY

Document Type

Conference Proceeding

Publication Date

2022

Department

Department of Mechanical Engineering-Engineering Mechanics

Abstract

Sorption thermal energy storage (STES) systems are considered promising thermal energy storage options as they could simultaneously store hot and cold energies. Liquid-based STES systems, however, suffer from a limited desiccant-refrigerant interfacial area available for absorption and desorption processes, thereby reducing the rate at which energy can be stored or recovered (i.e., power density). A dedicated absorber module could increase the desiccant-refrigerant interfacial area, but it makes the STES system more complex requiring control over desiccant pumping, distribution, and potential crystallization. Here, a passive STES approach is introduced to effectively increase the desiccant-refrigerant interfacial area for effective mass transfer during absorption and desorption processes. The new approach relies on engineered superhydrophobic membrane structures creating thin liquid films improving sorption rate and thus power density. In this extended abstract, early proof-of-concept experiments were conducted to scrutinize the validity of the proposed concept. Experimental results show that the peak temperature observed during the absorption process increases with the membrane surface area to salt mass ratio. The temperature lift observed during the absorption process increases from 8.9ºC in the case of no-membrane to 23.3ºC in the case of a membrane surface area to salt mass ratio of 2.48 m2/kgsalt. The insights from this work help to improve the cyclic longevity issue of sorption thermal energy storage systems for heat load shifting, shedding, and modulation in buildings and more.

Publication Title

Proceedings of the Thermal and Fluids Engineering Summer Conference

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