A method is provided for protecting a refrigerant vapor compression system during a standstill period following shutdown of the refrigerant vapor compression system. A method is provided for detecting a low refrigerant charge level in a refrigerant vapor compression system operating in a transcritical mode. A refrigerant vapor compression system is provided that includes a controller operative to perform a refrigerant charge detection method.

Standalone and self-contained cooling systems using compressed liquid and/or gas CO.sub.2 containers positioned in an insulated or non-insulated vessel encompassing a container which is either vertically positioned in an upright or an upside-down position.

The liquid and/or gas CO.sub.2 coolant is then released into a capillary system or flow metering system to allow the CO.sub.2 to enter a second body to where the CO.sub.2 coolant properties may be leveraged. The second body includes, by way of example, a plate, a cushion, a spot treatment pad for a person's muscle, or a cooler.

The temperature is controlled by a metering CO.sub.2 releasing system encompassing an electronic control device which sends alerts when pre-defined thresholds are exceeded.

The invention's metering CO.sub.2 releasing system may be triggered by an electronic or a thermostatic valve or may be triggered manually or by an electronic solenoid.

A refrigerant circuit has a liquid passage that allows a receiver to communicate with a utilization heat exchanger, and a first expansion valve provided in the liquid passage. The controller opens the first expansion valve when the compression element is in the stopped state and a pressure in the receiver exceeds a predetermined first pressure.

An electronic expansion valve (1) is provided, comprising an inlet (9), an outlet (8), an armature (2), a stop member (3), a biasing member (4) and a solenoid coil (12). The biasing member (4) provides a biasing force on the armature (2) towards a closing direction while the solenoid coil (12) may be provided with a current to provide a magnetic force on the armature (2) towards an opening direction. It is intended to provide an electronic expansion valve that may be controlled more precisely and has a higher safety. To this end the pressure difference between the inlet pressure and the outlet pressure provides a differential pressure force on the armature (2) towards an opening direction to allow a fluid flow from the inlet (9) to the outlet (8), and furthermore the armature (2) is displaced away from the stop member (3) to allow a fluid flow from the inlet (9) to the outlet (8) if the sum of the magnetic force and the differential pressure force on the armature (2) exceeds the biasing force. The invention furthermore relates to a refrigeration system comprising such an electronic expansion valve as well as a method for calibrating such an electronic expansion valve.

A circulating loop for transporting refrigeration to a remote location is connected serially between a Gifford-McMahon (GM) or GM type Pulse Tube cold head and the compressor. Either high pressure gas from the compressor can flow through the remote heat station before returning to the cold head or low pressure gas can flow from the cold head to the remote heat station before returning to the compressor. A first fraction of gas, which may include all of the gas at ambient temperature, enters a counter-flow heat exchanger, is cooled by the cold head, flows to the remote load, and then returns to ambient temperature as it flows through the counter-flow heat exchanger. The high or low pressure line may have a circulation control valve that diverts a second fraction of gas to flow directly between the cold head and compressor. A controller adjusts the circulation control valve to optimize the cooling of the load.

A safety valve includes a secondary-side refrigerant circuit that includes a secondary-side receiver that reserves a refrigerant, a flow path switching portion that includes a first connecting portion, a second connecting portion, and a third connecting portion connected to the secondary-side receiver, the flow path switching portion (96) that switches between a first state in which the third connecting portion communicates with the first connecting portion and a second state in which the third connecting portion communicates with the second connecting portion, and a safety valve that includes a safety valve connecting portion connected to the first connecting portion or the second connecting portion, and releases the refrigerant to outside when a refrigerant pressure in the secondary-side receiver satisfies a predetermined condition, in which at least the safety valve connecting portion is made of stainless steel.

A subcooling controller includes a sensor and a processor. The sensor measures one or more of a temperature external to a first heat exchanger that removes heat from carbon dioxide refrigerant, a temperature of the carbon dioxide refrigerant, and a pressure of the carbon dioxide refrigerant. The processor determines that one or more of the measured temperature external to the first heat exchanger, the temperature of the carbon dioxide refrigerant, and the pressure of the carbon dioxide refrigerant is above a threshold and in response to that determination, activates a subcooling system. The subcooling system includes a condenser, a second heat exchanger, and a compressor. The condenser removes heat from a second refrigerant. The second heat removes heat from the carbon dioxide refrigerant stored in a flash tank. The compressor compresses the second refrigerant from the second heat exchanger and sends the second refrigerant to the condenser.

A defrost system includes a thermosiphon defrost circuit that is provided by being branched from a circulation line, in which, at the time of defrosting, a CO.sub.2 refrigerant staying inside a fin-tube heat exchanger repeats a two-phase change of a gaseous form and reliquefaction, and which forms a CO.sub.2 circulation path together with the fin-tube heat exchanger; electromagnetic opening/closing valves that are closed at the time of defrosting and set the CO.sub.2 circulation path to a closed circuit; and a first electric heater arranged above the thermosiphon defrost circuit so as to be adjacent to the thermosiphon defrost circuit, and naturally circulates the CO.sub.2 refrigerant in the closed circuit at the time of defrosting.

A pressure control equipment changes a pressure in a tank from an initial pressure (atmospheric pressure) to a first pressure (negative pressure), so as to cause a liquid coolant from an external container to be injected into the tank. After a certain amount of the liquid coolant is injected into the tank, the pressure control equipment causes the pressure in the tank to change from the first pressure to a second pressure (atmospheric pressure). Then, after a settling period, spontaneous bumping is caused in the liquid coolant in the tank. Due to the spontaneous bumping, the pressure in the tank is rapidly, temporarily increased, and bubbles in the liquid coolant in the tank liquefy. With this process, cavities are deactivated.

An object is to, upon occurrence of a disproportionation reaction of a refrigerant, suppress impacts of the disproportionation reaction in a refrigeration cycle. A refrigeration device of the present disclosure includes a compressor, a heat source-side heat exchanger, a use-side heat exchanger, an expansion mechanism, a switching valve that switches between a heating operation state in which the use-side heat exchanger is caused to operate as a condenser and a cooling operation state in which the heat source-side heat exchanger is caused to operate as a condenser, and a control device. A working medium containing an ethylene-based fluoroolefin is used as a refrigerant. Upon detecting, in the heating operation state, that pressure of the working medium in a high pressure part including the compressor and the condenser has increased to a threshold value or higher, the control device controls the switching valve so as to switch operation from the heating operation state to the cooling operation state.