Research Publications

Electrification of space heating through air-source heat pump (ASHP) in residential homes is imperative to national decarbonization efforts. To overcome inefficient ASHP operations during cold periods, ASHP can be coupled with short-term thermal energy storage (TES). Of TES materials, thermochemical salt hydrates are particularly attractive due to their high energy storage densities and low losses. Existing technoeconomic analyses of TES only consider water heat storage, and salt hydrate TES analyses focus on grid-scale TES storage materials and characteristics that are not suitable to be applied to building applications. We quantify the household economic value of diverse salt-hydrate-based TES designs integrated with ASHPs in 4,800 representative single-family detached homes across 12 U.S. cities. Our research blends system-level technoeconomic optimization with bottom-up engineering models of thermochemical salt hydrate-based TES designs. Initial results for residential homes in Detroit, MI, show that TES can reduce annual electricity bill up to 7% ($130) in an individual home when fixed electricity rate is applied, and up to 24% ($430) in an individual home when time of use electricity rate is applied. Additionally, TES can serve as a useful demand response tool, capable of reducing peak load by 26% in an individual home. Cost saving from TES in an individual home can increase by more than 20% when storage size is doubled, and by more than 15% when switching from a low to high energy density salt.