A Pumped Thermal Energy Storage Cycle with Ccapacity for Concentrated Solar Power Integration

Joshua Dominic McTigue, Pau Farres-Antunez, Alexander White

Research output: Contribution to conferencePaper

21 Scopus Citations

Abstract

Pumped thermal energy storage (PTES) is a grid-scale energy management technology that stores electricity in the form of thermal energy. A number of PTES systems have been proposed using different thermodynamic cycles, including a variant based on a regenerated Brayton cycle that stores the thermal energy in liquid storage media (such as molten salts) via heat exchangers. This has several advantages, including the possibility to consider hybrid 'solar-PTES' systems employing technology developed by the concentrated solar power (CSP) industry. Such a hybrid system could charge the same hot stores using either solar energy or off-peak electricity (e.g, from nearby wind farms), increasing the capacity factor of the plant while employing the same heat engine during discharge. In this paper, two different configurations of solar-PTES systems are proposed and studied numerically: (i) a configuration in which an existing CSP plant is retrofitted with a Brayton heat pump, and (ii) a configuration in which a new hybrid plant uses the Brayton cycle both for charge and discharge. In both cases, the need to absorb and reject heat at conditions close to ambient temperature requires the Brayton cycle to incorporate intercooled stages at the cold side of the cycle. On the other hand, the intercooling process increases the minimum temperature of the cold stores, meaning that widely available and nonflammable antifreeze solutions (such as water-ethylene glycol) may be used as the cold storage medium.
Original languageAmerican English
Number of pages10
DOIs
StatePublished - 2019
Event2019 Offshore Energy and Storage Summit (OSES) - Brest, France
Duration: 10 Jul 201912 Jul 2019

Conference

Conference2019 Offshore Energy and Storage Summit (OSES)
CityBrest, France
Period10/07/1912/07/19

NREL Publication Number

  • NREL/CP-5500-74135

Keywords

  • concentrated solar power
  • energy efficiency
  • heat exchangers
  • pumped thermal energy storage
  • thermodynamic cycle analysis

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