Fewer temperature ties: scalable integration and broad selection of phase change materials for both heating and cooling†

Abstract

The change of seasons necessitates alternate heating and cooling systems, which are indispensable for nearly a third of the global population. Integrating latent thermal energy storage (LTES) and heat pumps (HPs) is gaining attention within the context of renewable energy strategies. However, fulfilling both heating and cooling requirements often requires the combined utilization of several tailored storage units, potentially escalating financial burdens and materials customization challenges related to scalability. Here, an intermediate latent thermal storage solution for dual-season usage is proposed. Combined with a double-effect quasi-two-stage heat pump, wide-temperature-range phase change materials are used in both heat and cold storage. Targeting global areas with seasonal heating and cooling demands, preferred materials are selected from 90 PCMs for 51 countries per region and 95 subnational areas. Through high-throughput screening, materials exhibiting phase change temperatures between 10.5 and 22 °C are pinpointed. In Arkansas, Beijing, Minnesota, and Shanghai, a significant enhancement in demand-oriented energy supply strategies is noted through deploying this system. The annual coefficient of performance enhancement yields an increment of 11.73% to 21.99%, compared to non-integrated heat pumps, and up to 51.31% versus separate heat and cold storage systems. Significantly, this integrated system overcomes cost barriers while minimizing land occupation, and exhibits great resilience amidst global climate change. These findings exemplify its scalable adaptability and potential in global areas, unveiling a global seasonal heating and cooling strategy for the first time and offering insights into alleviating global heating and cooling poverty.