Thermal Container Including a Thermal Unit

Abstract

In some embodiments, a thermal container may include a thermal tank, a cold source reservoir, and a tube forming a closed loop in contact with the thermal tank and with the cold source reservoir and configured to secure a thermal fluid. The thermal fluid may have a freeze temperature that is below zero degrees Celsius. The thermal container may further include a pump coupled to the tube and configured to circulate the thermal fluid between the cold source reservoir and the thermal tank when a temperature of the thermal tank exceeds a selected temperature. In some embodiments, the thermal container may further include a heating element coupled to the thermal tank and configured to apply heat to the thermal tank when the temperature falls below the selected temperature by more than a threshold amount.

What is claimed is: 
     
         1 . A thermal container comprising:
 a thermal tank;   a cold source reservoir;   a tube forming a closed loop in contact with the thermal tank and with the cold source reservoir and configured to secure a thermal fluid, the thermal fluid having a freeze temperature that is below zero degrees Celsius; and   a pump coupled to the tube and configured to circulate the thermal fluid between the cold source reservoir and the thermal tank when a temperature of the thermal tank exceeds a selected temperature.   
     
     
         2 . The thermal container of  claim 1 , wherein the thermal fluid comprises propylene glycol. 
     
     
         3 . The thermal container of  claim 1 , further comprising a control circuit coupled to the pump and configured to control the pump to adjust a flow rate of the thermal fluid flowing through the tube based on a difference between the selected temperature and the temperature within the thermal tank. 
     
     
         4 . The thermal container of  claim 3 , further comprising:
 one or more temperature sensors coupled to the control circuit and configured to determine a temperature of the thermal tank; and   wherein the control circuit is configured to adjust the flow rate based on the temperature.   
     
     
         5 . The thermal container of  claim 4 , further comprising:
 an interface coupled to the control circuit and accessible by a user to configure a temperature setting; and   wherein the control circuit is configured to adjust the flow rate based on the temperature relative to the temperature setting.   
     
     
         6 . The thermal container of  claim 1 , wherein the cold source reservoir defines an enclosure sized to receive a piece of dry ice having a temperature of approximately −110° Fahrenheit. 
     
     
         7 . The thermal container of  claim 1 , further comprising a heating element coupled to the thermal tank, the heating element configured to apply heat to the thermal tank when the temperature falls below the selected temperature by more than a threshold amount. 
     
     
         8 . The thermal container of  claim 1 , further comprising a reverse flow valve that may be controlled to reverse fluid flow from the thermal tank to the cold source reservoir when a temperature of one of the thermal tank and an ambient environment falls below a threshold temperature. 
     
     
         9 . An apparatus comprising:
 a thermal unit sized to fit within a portable thermal container defining an enclosure, the thermal unit including:
 an interface to receive a selected temperature; 
 one or more temperature sensors; and 
 a control circuit coupled to the interface and the one or more temperature sensors, the control circuit configured to selectively control one of a heating element and a cooling element to maintain a temperature of the enclosure within a range of the selected temperature. 
   
     
     
         10 . The apparatus of  claim 9 , wherein the heating element comprises at least one of a wire, a ribbon, and a strip configured to radiate heat in response to a control signal from the control circuit. 
     
     
         11 . The apparatus of  claim 10 , wherein at least a portion of the heating element is flexible. 
     
     
         12 . The apparatus of  claim 9 , wherein the cooling element comprises:
 a cold source reservoir;   tubing forming a closed loop, the tubing including a first portion coupled to a surface of the cold source reservoir and including a second portion; and   a pump coupled to the tubing and configured to circulate a thermal fluid through the closed loop based on control signals from the control circuit.   
     
     
         13 . The apparatus of  claim 12 , wherein the second portion of the tubing is formed from a flexible material. 
     
     
         14 . The apparatus of  claim 12 , wherein the cold source reservoir comprises a dry ice reservoir. 
     
     
         15 . The apparatus of  claim 9 , wherein the interface comprises at least one of a touchscreen, a display and a keypad. 
     
     
         16 . The apparatus of  claim 9 , wherein the interface comprises a transceiver configured to communicate with a computing device. 
     
     
         17 . An apparatus comprising:
 a container defining an enclosure;   a thermal unit sized to fit within the enclosure, the thermal unit including:
 an interface to receive a selected temperature; 
 one or more temperature sensors; and 
 a control circuit coupled to the interface and the one or more temperature sensors, the control circuit configured to selectively control one of a heating element and a cooling element to maintain a temperature of the enclosure within a range of the selected temperature. 
   
     
     
         18 . The apparatus of  claim 17 , wherein the cooling element comprises:
 a cold source reservoir;   tubing forming a closed loop, the tubing including a first portion coupled to a surface of the cold source reservoir and including a second portion; and   a pump coupled to the tubing and configured to circulate a thermal fluid through the closed loop based on control signals from the control circuit.   
     
     
         19 . The apparatus of  claim 17 , wherein the heating element comprises the heating element comprises at least one of a wire, a ribbon, and a strip configured to radiate heat in response to a control signal from the control circuit. 
     
     
         20 . The apparatus of  claim 17 , wherein the interface to receive a selected temperature includes at least one of a Universal Serial Bus interface and a wireless transceiver interface configured to communicate with a computing device to receive the selected temperature.