Evaluating the potential of thermochemical energy storage to decarbonize buildings: A case study in the United States
摘要
Thermal energy storage (TES) can support the integration of renewable energy in buildings, with the goal of decarbonizing heating loads that contribute significantly to the overall energy consumption and carbon emissions of this sector. Thermochemical salt hydrates that undergo a reversible chemical reaction with water vapor in air can be leveraged for compact heat storage in buildings. This work evaluates the viability of an open system thermochemical energy storage reactor that is charged using solar-thermal energy (solar collector) and discharged using ambient air in different representative climate regions in the United States. The charge–discharge performance of five salts is simulated over seasonal and daily storage timescales, with SrBr2 and MgCl2 emerging as the optimal materials that achieve high volumetric energy densities and outlet temperatures suitable for thermal end-uses (space and water heating). The size of a storage reactor for peak load shifting/shaving over a 4-h period is also estimated and found to be smaller than standard HVAC components in residential buildings. This suggests the promising potential of thermochemical materials as a compact thermal energy storage technology to decarbonize buildings over diurnal to seasonal timescales.
Graphical abstract HighlightsExploring the viability of open system thermochemical energy storage in the United States buildings sector. Integrating solar collectors to facilitate dehydration and location-specific hydration of five salts in a packed bed reactor. Analyzing energy supply and demand on a short (hourly) and long (seasonal) term basis for optimal salt selection. Offsetting space and water heating loads in residential buildings using thermal energy storage.
As decarbonization efforts grow, renewable energy and sustainable technologies offer avenues to curb and avert further harm to our environment and communities. However, renewable energy sources frequently face the challenge of intermittency. For example, solar collectors can harness abundant thermal energy during peak supply hours, but unfortunately, these hours often do not align with peak demand for thermal energy. This misalignment underscores the necessity to advance thermal energy storage technologies. Thermal energy storage paired with intermittent renewables is capable of storing energy and releasing it to offset high thermal loads in residential buildings such as space and water heating. Thermochemical energy storage materials in the form of salt hydrates are especially appealing in the residential sector due to their high energy density making it possible to design compact reactors, which is crucial for residential implementation where space is limited.