Patent ID: 9709337
Date: 2017-07-18
CPC Classifications: F28D,Y02E,Y10T

Claim:
1. An arrangement for storing thermal energy, comprising: a subterranean passage having a passage wall, the subterranean passage and the passage wall being formed out of an existing subterranean medium, the subterranean passage comprising a plurality of sections, the subterranean passage having a fluid therein, wherein at least one of the plurality of sections is curved and wherein said subterranean passage is configured as a helix; a channel having a cross-sectional area smaller than a cross-sectional area of the subterranean passage, the channel being formed out of the subterranean medium and extending from a first opening formed in the passage wall of one of the plurality of passage sections to a second opening formed in the passage wall of another of the plurality of passage sections such that a fluid connection is created between the passage sections; a fluid communication device including a first pipe arranged to extract a portion of the fluid from the subterranean passage, a pump fluidly connected to the first pipe, and a second pipe arranged to return the portion of the fluid to the subterranean passage; and a heat exchanger positioned above the subterranean medium and fluidly connected to the pump of the fluid communication device to receive the portion of the fluid extracted by the first pipe of the fluid communication device from the subterranean passage, perform a heat transfer process on the portion of the fluid, and fluidly connected to the second pipe of the fluid communication device to return the portion of the fluid to the second pipe for return to the subterranean passage, wherein the first opening and the second opening are located at different elevations of the subterranean passage such that the channel allows natural thermal convection between the passage sections that are connected by the fluid connection.