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An uninterruptible power supply (UPS) system based on supercapacitor and liquid nitrogen (LN2) hybridization is first introduced in this paper. Of the newly designed UPS, the supercapacitor reacts instantaneously once the main supply fails, and it also starts the LN2 power system to produce continuing electricity for the customer. This hybrid UPS system is of environment cleanness, long life time, easy maintenaince, etc. A 10kW model is analyzed in this study. A two-stage nitrogen expander is designed with the rated speed of 900rpm as the long time power generation device of the LN2 cycle. The UPS starting process calculation is carried out. The results reveal that commercial supercapacitors could fulfill this request. This UPS could be a competent choice for the UPS application. Further discussion indicates the LN2 power system could be used widely from UPS to low carbon vehicles. [ABSTRACT FROM AUTHOR]

Highlights: [•] Techno-economical and social analysis of energy storage is conducted for commercial buildings. [•] Methodologies for demand analysis, technical, economical and social evaluations are developed. [•] An illustrative example is analyzed for three kinds of energy storage systems. [Copyright &y& Elsevier]