Thermal management systems for extended operation

A thermal management method, comprising:

• transporting a refrigerant fluid along a refrigerant fluid flow path that extends from a refrigerant receiver through an evaporator to an exhaust line;
• extracting heat from at least one heat load in contact with the evaporator;
• transporting through an electronically controllable control device, an inert gas from a gas receiver to the refrigerant receiver at least prior to transporting or during transporting of the refrigerant fluid to control a vapor pressure in the refrigerant receiver;
• discharging at least a portion of the refrigerant fluid from the exhaust line so that the portion of discharged refrigerant fluid is not returned to the refrigerant fluid flow path and is exhausted to an ambient environment;
• measuring at least one thermodynamic property in the refrigerant fluid flow path with a sensor device that produces a control signal, the sensor device disposed along the refrigerant fluid flow path;
• and
• determining by an electronic controller system that comprises a processor, memory, storage media storing a computer program comprising executable instructions and I/O interfaces to receive sensor data and to transmit control signals, the storage media storing a computer program comprising executable instructions for processing the received sensor data from the sensor device and generate a control signal to control the electronically controllable flow control device to adjust operation of the electronically controllable control device, according to the at least one measured thermodynamic property.

A thermal management system, including:

• an open circuit refrigeration system that has a refrigerant fluid flow path, with the refrigerant fluid flow path comprising:
• a first receiver configured to store an inert gas;
• a second receiver configured to store a refrigerant fluid, with the second receiver coupled to the first receiver;
• an evaporator coupled to the second receiver, the evaporator configured to extract heat from at least one heat load that thermally contacts the evaporator;
• an exhaust line;
• and
• an electronically controllable flow control device;
• a sensor device disposed to sense at least one thermodynamic property in the refrigerant fluid flow path, where the sensor device is a first sensor device of a plurality of sensor devices, including the first sensor device, configured to measure a plurality of thermodynamic properties in the refrigerant fluid, and the plurality of sensor devices are configured to sense temperature and generate one or more electrical signals corresponding to temperature values to control a temperature of the at least one heat load in the evaporator;
• and
• an electronic controller system comprising a processor and memory and I/O interfaces to receive sensor data and to transmit control signals, and the electronic controller system further comprising storage media storing a computer program comprising executable instructions to:
• process the sensor data from the first sensor device;
• and
• generate a control signal to control the electronically controllable flow device.

A thermal management method, comprising:

• transporting a refrigerant fluid along a refrigerant fluid flow path that extends from a refrigerant receiver through an evaporator to an exhaust line;
• extracting heat from at least one heat load in contact with the evaporator;
• transporting through an electronically controllable control device, an inert gas from a gas receiver to the refrigerant receiver at least prior to transporting or during transporting of the refrigerant fluid to control a vapor pressure in the refrigerant receiver;
• discharging the refrigerant fluid from the exhaust line so that the discharged refrigerant fluid is not returned to the refrigerant fluid flow path;
• measuring at least one thermodynamic property in the refrigerant fluid flow path with a sensor device that produces a control signal, the sensor device disposed along the refrigerant fluid flow path;
• and
• determining by an electronic controller system that comprises a processor, memory, storage media storing a computer program comprising executable instructions and I/O interfaces to receive sensor data and to transmit control signals, the storage media storing a computer program comprising executable instructions for processing the received sensor data from the sensor device and generate a control signal to control the electronically controllable flow control device to adjust operation of the electronically controllable control device, according to the at least one measured thermodynamic property;
• and
• discharging the inert gas from the gas receiver into the refrigerant receiver when the vapor pressure in the refrigerant receiver exceeds a target pressure.