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Optimization of Cold Storage Efficiency in a Rankine‐Cycle‐Based Cold Energy Storage System
Author(s) -
Du Yanping,
Ding Yulong
Publication year - 2017
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.201600259
Subject(s) - cold storage , energy storage , environmental science , nuclear engineering , exergy efficiency , superheater , degree rankine , organic rankine cycle , thermal energy storage , rankine cycle , process engineering , energy recovery , waste heat , waste management , thermodynamics , exergy , materials science , engineering , heat exchanger , mechanical engineering , power (physics) , boiler (water heating) , energy (signal processing) , mathematics , physics , statistics , horticulture , biology
A 5 kW small‐scale cold energy storage (CES) system based on subcritical CO 2 was studied by thermodynamic analysis. If off‐peak electricity is used to heat CO 2 in the superheater, the predicted storage efficiency is 30–40 % if we consider the actual efficiencies of the key components in the CES system. In the ideal case, the maximum storage efficiency is as high as 43.9 %. The value of the storage efficiency is much larger and can be over 100 % if waste heat is utilized in the heater. The parametric study showed that the cold storage efficiency in the CES system was improved with an increase of the operating pressure and component efficiencies. The mass flow rate of CO 2 and the temperature at the inlet of the engine had a negative contribution to the storage efficiency because of the increased electricity consumption in the superheater.