Conceptualization and analysis of a novel combined sorption and phase-change material thermal storage system. (December 2020)

• Record Type: Journal Article
• Authors: Garimella, Srinivas; Keniar, Khoudor; Rattner, Alexander S.; Kini, Girish
• Is Part Of: Journal of energy storage. Volume 32(2020)
• Publication Date: 2020-12
• Subjects: Thermal storage -- Absorption -- Waste heat recovery -- Working pair -- Heat of mixing; Energy storage -- Periodicals; Energy storage -- Research -- Periodicals; 621.3126
• DOI: 10.1016/j.est.2020.101745
• Languages: English
• ISSNs: 2352-152X

Abstract

Highlights: A new sorption-based, long-term thermal storage cycle proposed. Enthalpy of dilution, instead of enthalpy of absorption, used to deliver heat. Evaporator and absorber replaced with a sensible heat exchanger and a liquid-liquid mixer. Second law criterion established to evaluate working fluids. Cycle integrated with PCM to achieve higher efficiencies for seasonal storage. Abstract: A new sorption-based thermal storage cycle is proposed. Energy is stored chemically by separating the constituents of highly non-ideal solutions, yielding much lower stand-by losses than in conventional approaches. The cycle avoids limitations of previously proposed sorption-based storage cycles by using a liquid-liquid mixer, and does not require a thermal source during discharge. A criterion based on a second law analysis is developed to evaluate potential working fluids for the cycle. Different cycle configurations are analyzed. An enhanced combined sorption and phase-change material (PCM) cycle is also investigated and compared with conventional thermal storage systems. For delivering 100 GJ of energy after 8 months, the combined cycle has an efficiency of 11% and lower storage volumes (down to 0.1 ×) than conventional thermal storage technologies. The energy density of the combined sorption-PCM system is 30 kWh m − 3 .