Patent ID: 9310103
Filing Date: 2016-04-12
CPC Classification: F24T,F28D,Y02E

Claim Text:
1. A method for storing thermal energy in, and recapturing thermal energy from, respectively, an underground energy storage ( 1 ), comprising at least four drilled holes ( 2 ) in the ground ( 3 ) and arranged at a distance from each other, said holes ( 2 ) having depths of at least 50 meters into the ground, said holes ( 2 ) arranged essentially along plural concentric circles ( 10 , 11 , 12 ), the plural concentric circles defining inner circles and outer circles, a control gear ( 7 ) arranged to control a valve system ( 6 ) arranged to direct a heat carrier ( 8 ), via a conduit ( 23 ) located in the holes, serially connecting the holes of each respective circle, and in the plural concentric circles, to different, respective ones of said holes arranged along each one of the circles to respectively thereby heat and cool surrounding ground along the circles so that the heat carrier can be circulated along different ones of the circles individually allowing a first of the circles to operate as a cooling source while a second of the circles operates as a heating source, the heat carrier being within a closed system and the ground surrounding the circles and holes being the underground energy storage, a temperature measuring coil ( 9 ) extending over a depth of at least one hole ( 2 ) of each circle, the temperature measuring coil ( 9 ) measuring one of the group consisting of i) the temperature of the heat carrier ( 8 ) within the hole, ii) the temperature inside the hole, and iii) a part of surrounding ground located in immediate proximity to the hole, the temperature measuring coil ( 9 ) comprising plural spaced-apart temperature sensors arranged along a depth direction of an extension of the hole such that one temperature sensor is located proximate a lower part of the hole and another temperature sensor is located proximate an upper part of the hole, the temperature measuring coil being coupled to the control gear ( 7 ) said method comprising: each temperature measuring coil regularly measuring the temperature at various depths in the corresponding hole, and reporting measured temperatures to the control gear, using the control gear ( when the temperature of the heat carrier ( when the temperature of the heat carrier ( in the heating and the cooling by the heat carrier flowing through the conduit, respectively, all wells along a current circle are heated or cooled simultaneously, wherein the ground (