Heat-release retardative cold conduction device with multi-cavity and multi-phase change and method of calculating transfer heat thereof

Abstract

The invention provides a heat-release retardative cold conduction device with multi-cavity and multi-phase change and a method of calculating the transfer heat thereof. The device comprises an inner cavity, a heat-release retardative cavity, and a phase-change cold storage cavity. The inner cavity is a hollow sealing structure with an unobstructed central core and two closed ends, and a refrigerant is placed in the cavity; the heat-release retardative cavity is encased on a bottom region outside of the inner cavity, and a phase-change heat storage material is placed in the heat-release retardative cavity; the phase-change cold storage cavity is encased on the outside of the inner cavity and is located in a region above the heat-release retardative cavity, wherein the phase-change cold storage cavity does not completely encase a top region outside of the inner cavity, and a phase-change cold storage material is placed in the phase-change cold storage cavity.

1 . A heat-release retardative cold conduction device with multi-cavity and multi-phase change, which is applicable to permafrost engineering and comprises:
 an inner cavity, wherein the inner cavity is a hollow sealing structure with an unobstructed central core and two closed ends, and a refrigerant is placed in the cavity;   a heat-release retardative cavity encasing a bottom region outside of the inner cavity, wherein a phase-change heat storage material is placed in the heat-release retardative cavity, the phase-change heat storage material undergoes phase transition at low temperatures to regulate spatiotemporal distributions of heat;   a phase-change cold storage cavity encasing the outside of the inner cavity and located in a region above the heat-release retardative cavity, wherein the phase-change cold storage cavity does not completely encase a top region outside of the inner cavity, and a phase-change cold storage material is placed in the phase-change cold storage cavity, when an outer wall temperature of the phase-change cold storage cavity reduces to a phase change temperature of the phase-change cold storage material, the phase-change cold storage material undergoes phase transition to store cold energy, thereby reducing the outer wall temperature of the phase-change cold storage cavity; and   a heat dissipation cavity encasing the outside of the inner cavity and located in a region above the phase-change cold storage cavity, wherein a unidirectional heat conductive material is placed in the heat dissipation cavity;   wherein, the heat-release retardative cavity and a corresponding portion of the inner cavity encased by the heat-release retardative cavity constitute a heat-release retardative evaporation section, the phase-change cold storage cavity and a corresponding portion of the inner cavity encased by the phase-change cold storage cavity constitute an intensive condensation section, and the heat dissipation cavity and a corresponding portion of the inner cavity encased by the heat dissipation cavity constitute a condensation section,   a double temperature difference is formed between the heat-release retardative evaporation section and the intensive condensation section, as well as between the heat-release retardative evaporation section and the condensation section, this ensures a balanced and continuous distribution of cooling in both space and time, thereby improving actual efficiency of cold conduction and working time.   
     
     
         2 . The heat-release retardative cold conduction device with multi-cavity and multi-phase change according to  claim 1 , further comprises:
 a heat insulation cavity encasing the outside of the inner cavity and located in a region above the heat-release retardative cavity and in a region below the phase-change cold storage cavity, wherein a heat insulation material is placed in the heat insulation cavity.   
     
     
         3 . The heat-release retardative cold conduction device with multi-cavity and multi-phase change according to  claim 2 , wherein the heat insulation cavity and a corresponding portion of the inner cavity encased by the heat insulation cavity constitute a heat insulation section. 
     
     
         4 . The heat-release retardative cold conduction device with multi-cavity and multi-phase change according to  claim 1 , wherein radiating fins are further mounted on the outer wall of the inner cavity, the outer wall of the phase-change cold storage cavity, and/or the outer wall of the heat dissipation cavity. 
     
     
         5 . The heat-release retardative cold conduction device with multi-cavity and multi-phase change according to  claim 4 , wherein the outside of the radiating fins is coated with a heat-insulating refrigeration coating. 
     
     
         6 . The heat-release retardative cold conduction device with multi-cavity and multi-phase change according to  claim 5 , wherein the heat-insulating refrigeration coating is a composite coating composed of a solar reflective material and a radiative refrigeration material,
 wherein the solar reflective material includes TiO2, HfO2, Al, Ag, and Cu, and the radiative refrigeration material includes SiO2, SiC, HfO2, aluminum phosphate, phosphite, C-containing elemental materials, and metal oxides such as Al2O3.   
     
     
         7 . The heat-release retardative cold conduction device with multi-cavity and multi-phase change according to  claim 1 , wherein the phase-change cold storage material is composed of a single phase-change material or a plurality of phase-change materials that undergo solid-liquid phase transition. 
     
     
         8 . The heat-release retardative cold conduction device with multi-cavity and multi-phase change according to  claim 2 , wherein the heat insulation material includes aerogel, aluminum silicate fiber, and polyurethane. 
     
     
         9 . The heat-release retardative cold conduction device with multi-cavity and multi-phase change according to  claim 1 , wherein the structure of the heat-release retardative cold conduction device with multi-cavity and multi-phase is made of carbon steel coated with an anti-corrosion coating on its surface. 
     
     
         10 . The heat-release retardative cold conduction device with multi-cavity and multi-phase change according to  claim 1 , wherein the refrigerant is liquid ammonia. 
     
     
         11 . A method of calculating transfer heat for a heat-release retardative cold conduction device with multi-cavity and multi-phase change, wherein the heat-release retardative cold conduction device with multi-cavity and multi-phase comprises:
 an inner cavity, wherein the inner cavity is a hollow sealing structure with an unobstructed central core and two closed ends, and a refrigerant is placed in the cavity;   a heat-release retardative cavity encasing a bottom region outside of the inner cavity, wherein a phase-change heat storage material is placed in the heat-release retardative cavity; and   a phase-change cold storage cavity encasing the outside of the inner cavity and located in a region above the heat-release retardative cavity, wherein the phase-change cold storage cavity does not completely encase a top region outside of the inner cavity, and a phase-change cold storage material is placed in the phase-change cold storage cavity;   wherein the heat-release retardative cavity and a corresponding portion of the inner cavity encased by the heat-release retardative cavity constitute a heat-release retardative evaporation section, the phase-change cold storage cavity and a corresponding portion of the inner cavity encased by the phase-change cold storage cavity constitute an intensive condensation section, and the method comprises at least the steps of   determining a first temperature difference based on a difference between the outer wall temperature of the heat-release retardative evaporation section and the outer wall temperature of the intensive condensation section as collected;   determining a first heat transfer resistance based on sum values of a heat-conducting resistance from the outer wall to the inner wall of the heat-release retardative evaporation section, an evaporative heat transfer resistance of the inner surface of the heat-release retardative evaporation section, a heat-conducting resistance from the inner wall to the outer wall of the intensive condensation section, a condensational heat transfer resistance of the inner surface of the intensive condensation section, and a heat transfer resistance between the outer wall of the intensive condensation section and the air; and   determining a transfer heat of the device based on the first temperature difference and the first heat transfer resistance.   
     
     
         12 . The method of calculating transfer heat for a heat-release retardative cold conduction device with multi-cavity and multi-phase change according to  claim 11 , wherein if the first temperature difference is greater than or equal to a predetermined working temperature difference for actuating the device, the transfer heat of the device is a ratio of the first temperature difference to the first heat transfer resistances, and if the first temperature difference is less than the working temperature difference, the transfer heat of the device is zero. 
     
     
         13 . The method of calculating transfer heat for a heat-release retardative cold conduction device with multi-cavity and multi-phase change according to  claim 12 , wherein parameters of a phase-change cold storage material in the intensive condensation section and parameters of a phase-change heat storage material in the heat-release retardative evaporation section are determined based on the first temperature difference and the first heat transfer resistance. 
     
     
         14 . The method of calculating transfer heat for a heat-release retardative cold conduction device with multi-cavity and multi-phase change according to  claim 13 , wherein a mixing amount of the phase-change cold storage material in the intensive condensation section is represented as: 
       
         
           
             
               m 
               ≥ 
               
                 
                   ∫ 
                   
                     
                       1 
                       
                         ∑ 
                         
                           R 
                           i 
                           ′ 
                         
                       
                     
                     ⁢ 
                     
                       ( 
                       
                         
                           T 
                           3 
                         
                         - 
                         
                           T 
                           2 
                         
                       
                       ) 
                     
                     ⁢ 
                     d 
                     ⁢ 
                     t 
                   
                 
                 H 
               
             
           
         
          where T 2  is the outer wall temperature of the intensive condensation section, T 3  is the outer wall temperature of the heat-release retardative evaporation section, the first temperature difference is T 3 −T 2 , the first heat transfer resistance is 
       
       
         
           
             
               
                 ∑ 
                 
                   R 
                   i 
                   ′ 
                 
               
               , 
             
           
         
       
        H is the latent heat of phase change of the phase-change cold storage material, m is a mixing amount of the phase-change cold storage material, and parameters of the phase-change cold storage material include the mixing amount and the latent heat of phase change of the phase-change cold storage material. 
     
     
         15 . The method of calculating transfer heat for a heat-release retardative cold conduction device with multi-cavity and multi-phase change according to  claim 13 , wherein the phase-change cold storage material has a phase change temperature of less than −1.5° C., and a degree of supercooling of less than 2° C., and parameters of the phase-change cold storage material include the phase change temperature and the degree of supercooling of the phase-change cold storage material. 
     
     
         16 . The method of calculating transfer heat for a heat-release retardative cold conduction device with multi-cavity and multi-phase change according to  claim 13 , wherein a mixing amount of the phase-change heat storage material in the heat-release retardative evaporation section is represented as: 
       
         
           
             
               
                 m 
                 ′ 
               
               ≥ 
               
                 
                   ∫ 
                   
                     
                       1 
                       
                         ∑ 
                         
                           R 
                           i 
                           ′ 
                         
                       
                     
                     ⁢ 
                     
                       ( 
                       
                         
                           T 
                           3 
                         
                         - 
                         
                           T 
                           2 
                         
                       
                       ) 
                     
                     ⁢ 
                     d 
                     ⁢ 
                     t 
                   
                 
                 
                   H 
                   ′ 
                 
               
             
           
         
          where T 2  is the outer wall temperature of the intensive condensation section, T 3  is the outer wall temperature of the heat-release retardative evaporation section, the first temperature difference is T 3 −T 2 , the first heat transfer resistance is 
       
       
         
           
             
               
                 ∑ 
                 
                   R 
                   i 
                   ′ 
                 
               
               , 
             
           
         
       
        H′ is the latent heat of phase change of the phase-change heat storage material, m′ is a mixing amount of the phase-change heat storage material, and parameters of the phase-change heat storage material include the mixing amount and the latent heat of phase change of the phase-change heat storage material. 
     
     
         17 . The method of calculating transfer heat for a heat-release retardative cold conduction device with multi-cavity and multi-phase change according to  claim 16 , wherein the phase-change heat storage material has a phase change temperature of less than −1.0° C., and a degree of supercooling of less than 2° C., and parameters of the phase-change heat storage material include the phase change temperature and the degree of supercooling of the phase-change heat storage material. 
     
     
         18 . A method of calculating transfer heat for a heat-release retardative cold conduction device with multi-cavity and multi-phase change, wherein the heat-release retardative cold conduction device with multi-cavity and multi-phase comprises:
 an inner cavity, wherein the inner cavity is a hollow sealing structure with an unobstructed central core and two closed ends, and a refrigerant is placed in the cavity;   a heat-release retardative cavity encasing a bottom region outside of the inner cavity, wherein a phase-change heat storage material is placed in the heat-release retardative cavity; and   a phase-change cold storage cavity encasing the outside of the inner cavity and located in a region above the heat-release retardative cavity, wherein the phase-change cold storage cavity does not completely encase a top region outside of the inner cavity, and a phase-change cold storage material is placed in the phase-change cold storage cavity;   wherein the heat-release retardative cavity and a corresponding portion of the inner cavity encased by the heat-release retardative cavity constitute a heat-release retardative evaporation section, and the phase-change cold storage cavity and a corresponding portion of the inner cavity encased by the phase-change cold storage cavity constitute an intensive condensation section;   in a condition where the phase-change cold storage cavity does not completely encase a top region outside of the inner cavity and a top portion of the inner cavity constitutes a condensation section, or in a condition where the heat-release retardative cold conduction device with multi-cavity and multi-phase change comprises a heat dissipation cavity which is encased on the outside of the inner cavity and is located in a region above the phase-change cold storage cavity, and the heat dissipation cavity and a corresponding portion of the inner cavity encased by the heat dissipation cavity constitute a condensation section, the method comprises the steps of   determining a first temperature difference based on a difference between the outer wall temperature of the heat-release retardative evaporation section and the outer wall temperature of the intensive condensation section as collected;   determining a first heat transfer resistance based on sum values of a heat-conducting resistance from the outer wall to the inner wall of the heat-release retardative evaporation section, an evaporative heat transfer resistance of the inner surface of the heat-release retardative evaporation section, a heat-conducting resistance from the inner wall to the outer wall of the intensive condensation section, a condensational heat transfer resistance of the inner surface of the intensive condensation section, and a heat transfer resistance between the outer wall of the intensive condensation section and the air;   determining a second temperature difference based on a difference between the outer wall temperature of the heat-release retardative evaporation section and the outer wall temperature of the condensation section as collected;   determining a second heat transfer resistance based on sum values of a heat-conducting resistance from the outer wall to the inner wall of the heat-release retardative evaporation section, an evaporative heat transfer resistance of the inner surface of the heat-release retardative evaporation section, a heat-conducting resistance from the inner wall to the outer wall of the condensation section, a condensational heat transfer resistance of the inner surface of the condensation section, and a heat transfer resistance between the outer wall of the condensation section and the air; and   determining a transfer heat of the device based on the first temperature difference, the second temperature difference, the first heat transfer resistance and the second heat transfer resistance.   
     
     
         19 . The method of calculating transfer heat for a heat-release retardative cold conduction device with multi-cavity and multi-phase change according to  claim 18 , wherein
 if both the first temperature difference and the second temperature difference are greater than or equal to a predetermined working temperature difference for actuating the device, the transfer heat of the device is the sum of a ratio of the first temperature difference to the first heat transfer resistances and a ratio of the second temperature difference to the second heat transfer resistance;   if the first temperature difference is greater than or equal to the working temperature difference and the second temperature difference is less than the working temperature difference, the transfer heat of the device is the ratio of the first temperature difference to the first heat transfer resistance;   if the second temperature difference is greater than or equal to the working temperature difference and the first temperature difference is less than the working temperature difference, the transfer heat of the device is the ratio of the second temperature difference to the second heat transfer resistance; and   if both the first temperature difference and the second temperature difference are less than the working temperature difference, the transfer heat of the device is zero.   
     
     
         20 . The method of calculating transfer heat for a heat-release retardative cold conduction device with multi-cavity and multi-phase change according to  claim 18 , wherein heat regulation is performed by a phase-change heat storage material in the heat-release retardative evaporation section during a phase transition process, which comprises:
 when the outer wall temperature of the condensation section is lower than the outer wall temperature of the intensive condensation section, heat from the heat-release retardative evaporation section is firstly dissipated through the condensation section; and   when the outer wall temperature of the condensation section is greater than or equal to the outer wall temperature of the intensive condensation section, heat from the heat-release retardative evaporation section is firstly dissipated by consuming the cold storage capacity of the intensive condensation section.   
     
     
         21 . The method of calculating transfer heat for a heat-release retardative cold conduction device with multi-cavity and multi-phase change according to  claim 18 , wherein refrigeration is performed by a phase-change cold storage material in the intensive condensation section during a phase transition process, which comprises:
 when the outer wall temperature of the intensive condensation section is reduced to the phase change temperature of the phase-change cold storage material, the phase-change cold storage material undergoes phase transition to store cold until the outer wall temperature of the intensive condensation section is reduced to or even lower than the phase change temperature of the phase-change cold storage material.