Analysis of various system designs for adsorption cycle in building heating applications

Abstract

Buildings are major energy consumers, highlighting the need for efficient thermal energy storage to reduce reliance on non-renewable sources. Adsorption-based systems offer significant energy savings for heating applications. This research compares four critical adsorption-based cycles: adsorption thermal energy storage, adsorption heat transformer, adsorption mass recovery with heating and cooling, and a novel combined cycle. The study uncovers new insights into temperature and pressure control challenges through lumped parameter modeling. These dynamic modeling results advance our understanding and optimization of adsorption systems, enhancing their feasibility and efficiency for building heating. The adsorption mass recovery cycle demonstrates superior energy storage density (289 kW h/m³) compared to the adsorption heat transformer cycle (240 kW h/m³) and the adsorption thermal energy storage cycle (157 kW h/m³). It also has the highest water uptake (0.56 kg/kg), surpassing the other two cycles. Despite its pressure fluctuations and temperature instability challenges, the adsorption mass recovery cycle outperforms the adsorption heat transformer and adsorption thermal energy storage cycles in energy storage density. The novel combined cycle optimizes heat storage and release, achieves the highest energy storage density (302 kW h/m³), and outperforms the individual cycles. The combined cycle's performance was evaluated in a home in South Korea, revealing significant energy savings and proving an effective solution for enhancing energy efficiency in building heating systems. This research addresses a crucial gap and provides a foundation for future advancements in thermal energy storage.