Thermodynamic performance and cost optimization of a novel hybrid thermal-compressed air energy storage system design

Journal Article · Fri May 11 00:00:00 EDT 2018 · Journal of Energy Storage

DOI:https://doi.org/10.1016/j.est.2018.05.004· OSTI ID:1441174

Houssainy, Sammy ^[1]; Janbozorgi, Mohammad ^[2]; Kavehpour, Pirouz ^[2]

---

1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
2. Univ. of California, Los Angeles, CA (United States)

Compressed Air Energy Storage (CAES) can potentially allow renewable energy sources to meet electricity demands as reliably as coal-fired power plants. However, conventional CAES systems rely on the combustion of natural gas, require large storage volumes, and operate at high pressures, which possess inherent problems such as high costs, strict geological locations, and the production of greenhouse gas emissions. A novel and patented hybrid thermal-compressed air energy storage (HT-CAES) design is presented which allows a portion of the available energy, from the grid or renewable sources, to operate a compressor and the remainder to be converted and stored in the form of heat, through joule heating in a sensible thermal storage medium. The HT-CAES design incudes a turbocharger unit that provides supplementary mass flow rate alongside the air storage. The hybrid design and the addition of a turbocharger have the beneficial effect of mitigating the shortcomings of conventional CAES systems and its derivatives by eliminating combustion emissions and reducing storage volumes, operating pressures, and costs. Storage efficiency and cost are the two key factors, which upon integration with renewable energies would allow the sources to operate as independent forms of sustainable energy. The potential of the HT-CAES design is illustrated through a thermodynamic optimization study, which outlines key variables that have a major impact on the performance and economics of the storage system. The optimization analysis quantifies the required distribution of energy between thermal and compressed air energy storage, for maximum efficiency, and for minimum cost. This study provides a roundtrip energy and exergy efficiency map of the storage system and illustrates a trade off that exists between its capital cost and performance.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• Grant/Contract Number: AC36-08GO28308
• OSTI ID: 1441174
• Report Number(s): NREL/JA-5500-71685
• Journal Information: Journal of Energy Storage, Vol. 18, Issue C; ISSN 2352-152X
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

25 ENERGY STORAGE
air energy storage
storage efficiency
thermodynamic optimization