Heat pipe, system and method for switching and/or programming a transport of heat

Abstract

A heat pipe having a working chamber having an evaporator region operatively connected to a heat source, and a condenser region operatively connected to a heat sink. A working fluid is provided in the working chamber, and heat is transferred from the heat source to the heat sink by the working fluid in a first state of operation. The heat pipe is a switchable and/or programmable thermal diode or a switchable and/or programmable heat switch, at least one activatable functional material is provided, which is arranged and configured to keep the evaporator region free of the working fluid and/or to prevent the working fluid from evaporating in a second state of operation, in order to reduce and/or hinder heat transfer and/or to alter the preferential direction of heat conduction. A system and method for switching and/or programming heat transfer in a heat pipe are also provided.

1 . A heat pipe ( 1 ), comprising:
 at least one working chamber ( 2 ) having at least one evaporator region ( 3 ) operatively connected to a heat source, and at least one condenser region ( 4 ) operatively connected to a heat sink;   a working fluid ( 5 ) in the working chamber ( 2 ) by which heat is transferred from the heat source to the heat sink in a first state of operation;   wherein the heat pipe ( 1 ) is configured as at least one of a switchable or programmable thermal diode or as at least one of a switchable or programmable heat switch;   at least one activatable functional material is arranged and configured to at least one of keep the evaporator region ( 3 ) free of the working fluid ( 5 ) or prevent the working fluid ( 5 ) from evaporating in a second state of operation, in order to at least one of reduce or hinder heat transfer alter a preferential direction of heat conduction.   
     
     
         2 . The heat pipe as claimed in  claim 1 , wherein
 the heat pipe ( 1 ) is configured as a switchable thermal diode or heat switch, and the at least one activatable functional material is configured to at least partly change properties in an external field.   
     
     
         3 . The heat pipe as claimed in  claim 1 , wherein
 the heat pipe ( 1 ) is configured as a programmable thermal diode or heat switch, and the at least one activatable functional material is configured to change properties depending on conditions within the working chamber ( 2 ).   
     
     
         4 . The heat pipe as claimed in  claim 1 , wherein
 the working chamber ( 2 ) has a closed volume configured for heat transfer by convection of the working fluid ( 5 ) that is evaporated and for reverse transfer of the working fluid ( 5 ) that is condensed.   
     
     
         5 . The heat pipe as claimed in  claim 4 , wherein
 the heat pipe ( 1 ) is formed with a fluid circuit for the working fluid ( 5 ), and the fluid circuit comprises a fluid recycling conduit for transport of the condensed working fluid ( 5 ) from the condenser region ( 4 ) back to the evaporator region ( 3 ).   
     
     
         6 . The heat pipe as claimed in  claim 4 , wherein
 the closed volume has at least one: of a) at least one of a fluid-phobic coating ( 6 ) or structuring in the evaporator region ( 3 ) or b) at least one of a fluid-philic coating ( 6 ) or structuring in the condenser region ( 4 ).   
     
     
         7 . The heat pipe as claimed in  claim 1 , wherein
 the at least one activatable functional material comprises a switchable coating of at least one of the evaporator region ( 3 ) or the condenser region ( 4 ), and   at least a surface property of the coating of the evaporator region ( 3 ) is variable from fluid-philic to fluid-phobic.   
     
     
         8 . The heat pipe as claimed in  claim 7 , wherein
 the switchable coating ( 6 ) at least one of is or comprises ORMOCER®.   
     
     
         9 . The heat pipe as claimed in  claim 1 , wherein
 the at least one functional material comprises a reservoir for the working fluid ( 5 ).   
     
     
         10 . The heat pipe as claimed in  claim 9 , wherein
 the reservoir for the working fluid ( 5 ) comprises of a gel as an adsorbent or as mesoscopically structured surface.   
     
     
         11 . The heat pipe as claimed in  claim 9 , wherein
 the reservoir for the working fluid ( 5 ) comprises a polymer gel having a temperature-induced volume phase transition.   
     
     
         12 . A system comprising:
 the heat pipe as claimed in  claim 1 ; and any of the preceding claims   means of applying a field in order to alter properties of the activatable functional material.   
     
     
         13 . The system as claimed in  claim 12 , wherein
 the means of applying a field comprise field generators for at least one of an electrical field, a magnetic field, a stress-strain field, generation of light, light, generation of heat, or generation of refrigeration.   
     
     
         14 . The system as claimed in  claim 12 , wherein
 the system includes a combination of two of the activatable functional materials, with one of the two activatable functional materials comprising a liquid reservoir fir the working fluid and the other of the functional material s comprising an ORMOCER® of variable fluid-philic/fluid-phobic properties.   
     
     
         15 . A method of at least one of switching or programming heat transfer in a heat pipe having at least one working chamber ( 2 ) having at least one evaporator region ( 3 ) and at least one condenser region ( 4 ), and a working fluid ( 5 ), the method comprising the following method steps:
 A) evaporating the working fluid ( 5 ) in the evaporator region ( 3 ), and transferring heat by the gaseous working fluid ( 5 ) from the evaporator region ( 3 ) to the condenser region ( 4 ), and   B) condensing the working fluid ( 5 ) in the condenser region ( 4 ), and removing the heat to a heat sink,   operating the heat pipe ( 1 ) as a thermal diode or thermal switch, and altering a thermal conductivity by the applying of an external field and/or depending on conditions within the working chamber ( 2 ).   
     
     
         16 . The method as claimed in  claim 15 , wherein
 the thermal conductivity of the thermal diode or of the heat switch is altered by at least one of keeping the evaporator region ( 3 ) free of the working fluid ( 5 ) or stopping the working fluid ( 5 ) from evaporating.   
     
     
         17 . The method as claimed in  claim 15 , further comprising reversing
 a preferential direction of thermal conduction of the thermal diode by exchanging is surface properties of an evaporator region ( 3 ) and a condenser region ( 4 ) by the applying of an external field and/or depending on conditions within the working chamber ( 2 ).