Thermal Container Including a Thermal Unit
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.
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.