Heat exchange element and systems and method for exchanging thermal energy

Abstract

A heat exchange element, comprising: an outer flow element, an inner flow element arranged within the outer flow element, an element flow path comprising forward flow path and a return flow path, wherein the forward flow path is arranged between the outer flow element and the inner flow element, the return flow path is arranged within the inner flow element, the element flow path is configured to guide a working fluid from the forward flow path to the return flow path, a pressure control element, arranged fluidically between the forward flow path and the return flow path.

1 . A heat exchange element, comprising
 an outer flow element,   an inner flow element arranged within the outer flow element,   an element flow path comprising forward flow path and a return flow path, wherein.
 the forward flow path is arranged between the outer flow element and the inner flow element,. 
 the return flow path is arranged within the inner flow element,. 
 the element flow path is configured to guide a working fluid from the forward flow path to the return flow path, and 
   a pressure control element, arranged fluidically between the forward flow path and the return flow path.   
     
     
         2 . The heat exchange element according to  claim 1 , wherein the heat exchange element is a heat absorption element, wherein the pressure control element is configured to reduce the pressure of the working fluid for converting at least a part of the working fluid from a liquid to a gaseous state, wherein the pressure control element is configured to maintain the pressure in the forward flow path at a pressure at which the working fluid is in the liquid state. 
     
     
         3 . The heat exchange element according to  claim 1 , wherein the pressure control element has at least a first position having a first fluid return opening and second position having a second fluid return opening, wherein the second fluid return opening is greater than the first fluid return opening. 
     
     
         4 . The heat exchange element according to  claim 3 , wherein the pressure control element is configured to be arranged in the first or the second position by a pressure difference between the working fluid in the forward flow path and the working fluid in the return flow path. 
     
     
         5 . The heat exchange element according to  claim 1 , further comprising a control unit configured to control the pressure control element. 
     
     
         6 . The heat exchange element according to  claim 1 , wherein the pressure control element is a pipe section with a small pipe diameter, for example having a capillary section or a pipe section having a small orifice. 
     
     
         7 . The heat exchange element according to  claim 1 , wherein the pressure control element comprises a pipe section with a diameter reduction element arranged in the return flow path at the distal end of the inner flow element, wherein the pipe diameter defined by the diameter reduction element is smaller than a pipe diameter of the inner flow element, such that, downstream of the pressure control element, the return flow path comprises a larger diameter than the small pipe diameter. 
     
     
         8 . The heat exchange element according to  claim 7 , further comprising
 a space eliminator being arranged coaxially to the diameter reduction element and within the diameter reduction element,   a flange configured to receive a space eliminator flange, wherein the space eliminator is fixedly connected to the space eliminator flange, extending through an opening of the flange;   
       wherein heat exchange element is part of a modular system comprising a plurality of space eliminator flanges, each comprising a space eliminator of different size. 
     
     
         9 . The heat exchange system according to  claim 8 , wherein the pressure control element comprises an overpressure protection system comprising a resilient member, e.g. a spring, wherein the resilient member is mechanically connected to the diameter reduction element, and is configured to exert a biasing force onto said diameter reduction element, wherein the diameter reduction element is configured to move relative to the space eliminator when a pressure force exerted by the fluid onto the diameter reduction element exceeds the biasing force. 
     
     
         10 . The heat exchange element according to  claim 1 , the forward flow path has an annular cross section and the return flow path as a circular cross section. 
     
     
         11 . The heat exchange element according to  claim 1 , wherein the pressure control element is arranged at a distal outer end of the inner flow element. 
     
     
         12 . A modular heat exchange element, comprising
 a heat exchange element according to  claim 1 , wherein the inner flow element has an inner flow element diameter; and   at least one further inner flow element having a further inner flow element diameter which is different from the inner flow element diameter, wherein modular heat absorbing is configured for arranging either one of the inner flow element and the further inner flow element modularly inside the outer flow element, thereby allowing to modify the forward flow path and the return flow path.   
     
     
         13 . A system for exchanging thermal energy, comprising
 an inlet pipe configured to receive a working fluid in liquid state;   an outlet pipe configured to guide the working fluid in an at least partially gaseous state; and   a plurality of heat exchange elements according to  claim 1 , wherein the heat exchange elements are arranged fluidically in parallel between the inlet pipe and the outlet pipe.   
     
     
         14 . The system according to  claim 13 , comprising
 a further inlet pipe configured to receive the working fluid or a further working fluid in liquid state;   a further outlet pipe configured to guide the working fluid or the further working fluid, respectively, in an at least partially gaseous state; and   a further plurality of the heat exchange elements, wherein the further heat exchange elements are arranged fluidically in parallel between the further inlet pipe and the further outlet pipe;   
       wherein the heat exchange elements and the further heat exchange elements extend in opposite directions, are arranged physically parallel to each other, and are arranged in an alternating arrangement. 
     
     
         15 . A thermal buffer system, e.g. a molten salt buffer system, comprising
 a housing configured to receive a buffer material, e.g. an inorganic salt,.   a system for absorbing thermal energy according to  claim 13 , wherein the heat exchange elements are arranged in the housing,   a system for expelling thermal energy, comprising a plurality of heat expelling elements, wherein the thermal buffer system is configured to provide thermal energy to the buffer material with the system for expelling thermal energy, and absorb thermal energy from the buffer material with the system for absorbing thermal energy.   
     
     
         16 . A system for generating electricity, comprising the system according to  claim 13 , wherein the heat exchange elements are configured to receive solar heat, further comprising a gas turbine fluidly connected to the outlet pipe and configured to be convert thermal energy from the working fluid in gaseous state into electric energy. 
     
     
         17 . A method for absorbing or expelling thermal energy, and/or for exchanging thermal energy between a gas and a liquid, and/or for buffering thermal energy, and/or for generating electricity, wherein the method comprises a step of using a heat exchange element according to  claim 1 . 
     
     
         18 . A method for absorbing thermal energy, comprising the following steps:
 guiding a working fluid in liquid state through a forward flow path, wherein the forward flow path is arranged between an outer flow element and an inner flow element of a heat exchange element;   guiding the working fluid through a return flow path, wherein the return flow path is arranged within the inner flow element, wherein the working fluid flows through a pressure control element before flowing into the return flow path,   
       further comprising a step of reducing the pressure of working fluid when the working fluid flows through the pressure control element, thereby converting at least a part of the working fluid from a liquid to a gaseous state.