Abstract
Thermal energy storage systems in buildings can store cooling/heating energy during non-peak load hours or when renewable energy sources are available for later use when demanded. Using the building envelope as a thermal battery can help to shave the peak load, reduce the burden in electric grids, and enhance the occupant's thermal comfort. Sensible energy storage on wall systems such as thermally activated building systems can provide an active thermal storage strategy. However, most of the stored energy is used through passive means directed by the thermal lag, which can impede the on-demand release of the stored energy. Integrating active insulation systems with building thermal storage systems can increase the flexibility of charging and discharging time and duration. In this study, a wall system equipped with an active insulation system and thermally activated storage system was designed, and its performance on active cooling energy contribution was studied. The performances of energy storage (charging), release (discharging) of the thermal energy storage energy, and the active insulation system were studied separately and together as an integrated system. Results showed that the thermal properties of the thermal energy storage core material and the pipe spacing of both embedded pipes in the thermal energy storage and hydronic pipes used in the active insulation system affected the wall performance the most out of all the tested wall system parameters. During discharging, the heat flux into the wall was as high as 81.92 W/m2. The active insulation system's dynamic R-value varied between less than 1ft2•°F•h/BTU (0.18 m2•K/W) to 98% of the equally thick foam insulation's R-value.
| Original language | English |
|---|---|
| Article number | 103815 |
| Journal | Journal of Energy Storage |
| Volume | 46 |
| DOIs | |
| State | Published - Feb 2022 |
Funding
This manuscript has been authored in part by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ). This work was funded by the Federal Energy Management Program (FEMP) of the US Department of Energy (DOE), under Contract No. DE-AC05–00OR22725. A portion of this research used resources at the Building Technologies Research and Integration Center, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. This work was funded by the Federal Energy Management Program (FEMP) of the US Department of Energy (DOE), under Contract No. DE-AC05–00OR22725 . A portion of this research used resources at the Building Technologies Research and Integration Center, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory.
| Funders | Funder number |
|---|---|
| U.S. Department of Energy | DE-AC05–00OR22725 |
| Office of Science | |
| Oak Ridge National Laboratory |
Keywords
- Active insulation system
- Convective water loop
- Cooling load
- Heat flux
- Hydronic system
- Peak-load
- Thermal energy storage
