当前无间断电源（UPS）的储能单元以化学蓄电池为主，能量密度低、寿命短、维护费用高、污染环境等。本研究提出一种新型的基于超级电容与液氮动力耦合的无间断电源系统，并重点研究液氮动力循环系统，它包括一个开式郎肯（Rankine）循环和一个闭口布雷顿（Brayton）循环，二者相耦合，从而充分回收利用液氮冷能，并有蓄热换热器为膨胀机前的氮气提供预热。该无间断电源系统具有反应迅速、能量密度高（储存、输出）、环境友好、寿命长、易维护、剩余电量易检测等优点。本项目将深入研究该系统的基础理论、总体热力学性能、高压低温流体的流动与传热特性、相变蓄热材料特性、蓄热换热机理以及高压比膨胀机的设计优化等科学问题，同时建立基于超级电容与液氮动力系统耦合的无间断电源系统原理试验台，为基于新型物理储能的无间断电源的设计提供理论基础和原理验证。

The Uninterruptible Power Suppply (UPS) generally utilizes chemical battery as the electricity storage unit at present, which comes up with some drawbacks, such as low energy density, short life time, high-cost maintenance, hazardous effect to the enviroment, etc.. An UPS system based on supercapacitor and liquid nitrogen power cycle hybridization was first introduced in this research proposal. And it will mainly investigate the liquid nitrogen power cycle. This liquid nitrogen cycle combines an open Rankine cycle and a closed Brayton cycle, which could recover the cold energy of the liquid energy. Moreover, a thermal storage unit is also engaged, which preheats the nitrogen before entering the expander to generate power.The proposed UPS system may reveal merits as follows: fast reaction when outage occurs, high energy density (both storage and discharging processes), environmentally benign technique, long life time, easy maintenance, easy inspection of the remained energy and so on. The project will carry out fundamental research in depth including: the systematic thermodynamic theory, fluid flow and heat transfer characteristics under high-pressure and low-temperature conditions, phase change material property, thermal energy storage and heat transfer mechanism, to develop and optimize high pressure ratio expander, etc.. It will build up the first demonstration of an UPS based on supercapacitor and liquid nitrogen cycle hybridization system. It could provide theoretical principle and verification for the UPS design based on physical energy storage technology.