Patent ID: 9671175
Date: 2017-06-06
CPC Classifications: F01K,F25B,F28D,Y02E

Claim:
1. A system for reversibly storing electrical energy as thermal energy comprising: a reversible subcritical vapour-liquid cycle having a working fluid flow path cycling through a hot storage fluid heat exchanger configured and arranged to exchange thermal energy between a working fluid, as the working fluid changes phase, and a hot storage fluid, a vapour pressure changing apparatus configured to change pressure of the working fluid in a vapour phase and arranged between and fluidly adjacent the hot storage fluid heat exchanger and a cold storage fluid heat exchanger, the cold storage fluid heat exchanger arranged fluidly adjacent the vapour pressure changing apparatus, configured and arranged to exchange thermal energy between the working fluid, as the working fluid changes phase, and a cold storage fluid, a liquid pressure changing apparatus arranged fluidly adjacent the cold storage fluid heat exchanger opposite the vapour pressure changing apparatus, configured to change pressure of the working fluid in a liquid phase, and an inter storage heat exchanger arranged fluidly between the liquid pressure changing apparatus and the hot storage fluid heat exchanger, configured and arranged to exchange sensible heat of the working fluid with a storage fluid; a hot storage fluid flow path cycle passing through the hot storage fluid heat exchanger and a hot storage fluid tank storing the hot storage fluid; a cold storage fluid flow path cycle passing through the cold storage fluid heat exchanger and a cold storage fluid tank storing the cold storage fluid; and an inter storage tank flow path cycle fluidly connecting the hot storage fluid tank to the cold storage fluid tank via the inter storage heat exchanger.