A cooling assembly includes an evaporator containing a primary cooling medium, a passive condenser, and a heat exchanger. When a secondary cooling medium is provided to the heat exchanger, the primary cooling medium in the gas phase switches from being received by the passive condenser to the heat exchanger without operating any valves located between the evaporator and the passive condenser and between the evaporator and the heat exchanger. The primary cooling medium circulates between the evaporator and the passive condenser and between the evaporator and the heat exchanger by natural circulation and gravity without a pump in the flow path of the primary cooling medium between the heat exchanger and the evaporator and between the passive condenser and the evaporator to circulate the primary cooling medium.

A system and method for operating a selective emitter is provided. One embodiment comprises a heat sink that absorbs heat from an ambient environment, a heat pipe comprising a cooling portion thermally coupled to the heat sink, a wick portion and a heat dissipation portion, and a selective emitter that is thermally coupled to the cooling portion of the heat pipe. The selective emitter converts absorbed heat into radiative energy that is emitted out through the Earth's atmosphere.

A two-phase cooling system with flow boiling, characterized in that a closed hydraulic circuit apparatus of a heat transfer refrigerating fluid is provided, including: a pump for a refrigerating fluid which, at least in some stretches of the circuit, is two-phase liquid-vapor or multi-phase; a heat sink-evaporator configured to transfer heat by conduction from a component to be cooled to the refrigerating fluid; a condenser, capable of condensing the vapor which develops on the evaporator while simultaneously dissipating the heat given by the refrigerating fluid both by conduction, convection and radiation and by condensation into the environment; a tank which also acts as an expansion vessel, or a tank and an expansion vessel which are distinct and connected to each other; and a plurality of sensors, including flow rate, pressure and temperature sensors and an electronic control system of the pump.

A refrigeration system includes a heat exchanger configured to place a cooling fluid in a heat exchange relationship with a working fluid, a free-cooling circuit having a pump configured to circulate the working fluid through the heat exchanger and a condenser, a flow control valve configured to control a flow rate of the working fluid to the condenser, a condenser bypass valve configured to control a flow rate of the working fluid that bypasses the condenser, and a controller configured to adjust a position of the flow control valve, a position of the condenser bypass valve, a speed of a fan of the condenser, a speed of the pump, and a temperature of a heater based on an ambient temperature, a temperature of the working fluid leaving the condenser, the position of the flow control valve, the position of the condenser bypass valve, or a combination thereof.

A refrigerator based on a molecular sieve, including a first molecular sieve device, a second molecular sieve device, a reversing valve, and a balancing valve, wherein an air flow alternately passes through the first molecular sieve device and the second molecular sieve device through the reversing valve, and then flows back through the balancing valve, so that the first molecular sieve device and the second molecular sieve device are regenerated. The first molecular sieve device and the second molecular sieve device are capable of separating a refrigerant from a depressurized gas, and the refrigerant is condensed after reaching a certain concentration to become a liquid refrigerant, and then enters an evaporator again for refrigeration.

A refrigeration plant including: a first enclosure containing water in the liquid state at a temperature lower than or equal to the temperature of the triple point of water or higher than the temperature of the triple point of water by less than 10° C., and water in the gaseous state at a first pressure equal to the saturated vapor pressure of the water in equilibrium with the pressure of the water in the liquid state; a second enclosure at a second pressure strictly higher than the first pressure by a factor of at least two; a compression device connecting the first enclosure to the second enclosure; a condensing device adapted to condense the water in the gaseous state in the second enclosure into water in the liquid state; and a cold power extraction device for extracting cold power in the first enclosure.

A liquid cooled heat exchanger includes first and second heat exchange chambers that are in thermal communication. The first heat exchange chamber is downstream of the second heat exchanges chamber and receives heat from a heat generating device, such as an electronic circuit. Heat in the first heat exchange chamber can be transferred to the second heat exchange chamber to increase the temperature of a subcooled liquid working fluid in the second heat exchange chamber. This can render a pressure drop across the heat exchanger that is relatively insensitive to a fraction of liquid that is vaporized in the first heat exchange chamber.

Heat transfer devices and systems are provided for the rapid cooling of pulsed high-powered, high-flux devices using flash boiling. Such devices comprise at least two fluidly connected chambers and a heat exchanger in thermal communication with a heat source. A flash boiling event is actively triggered at a location close to the heat source by rapid depressurization of the chamber containing a multi-phase coolant. This boiling process allows for high heat transfer rates from the heat source into the chambers due to the latent heat of vaporization, which results in the rapid cooling of the heat source. A porous medium may also be positioned within a chamber of the device to enhance boiling nucleation and extended surface heat transfer. Methods of rapidly cooling pulsed heat sources are also provided using the devices and systems hereof.

A system includes a heat exchanger mounted to the brackets and receiving cryogen, the heat exchanger having a vertical inlet coupled in parallel to a plurality of equal size horizontal tubes each traversing a width of the heat exchanger and further coupled in parallel to a vertical outlet pipe with an outlet diameter at least twice an inlet tube diameter; a temperature sensor; a thermostat that monitors the temperature sensor and maintains a predetermined temperature set point by communicating with a solenoid valve coupled to the heat exchanger; an exhaust line coupled to the outlet pipe that expels exhaust gas outside the enclosed facility; multiple fans attached to the heat exchanger; and a fail-safe oxygen sensor to protect a biological object in the enclosed facility.

A refrigeration system includes a heat exchanger configured to place a cooling fluid in a heat exchange relationship with a working fluid, a free-cooling circuit having a pump configured to circulate the working fluid through the heat exchanger and a condenser, a flow control valve configured to control a flow rate of the working fluid to the condenser, a condenser bypass valve configured to control a flow rate of the working fluid that bypasses the condenser, and a controller configured to adjust a position of the flow control valve, a position of the condenser bypass valve, a speed of a fan of the condenser, a speed of the pump, and a temperature of a heater based on an ambient temperature, a temperature of the working fluid leaving the condenser, the position of the flow control valve, the position of the condenser bypass valve, or a combination thereof.