A sensor control system includes: a refrigerant leak sensor configured to, when powered, measure an amount of a refrigerant present in air outside of a heat exchanger of a refrigeration system, where the heat exchanger is located within a building that is at least one of heated and cooled by the refrigeration system; and a power control module configured to one of: continuously power the refrigerant leak sensor; and disconnect the refrigerant leak sensor from power when a blower that moves air past the heat exchanger is on.

An air-conditioning apparatus includes a fan configured to deliver air toward the outdoor heat exchanger, a power unit configured to supply electric power to the fan, a fan input detector configured to detect a physical value related to the electric power supplied to the fan, and a controller configured to control the four-way valve to switch between a first operation in which the outdoor heat exchanger functions as an evaporator and a second operation in which the outdoor heat exchanger functions as a condenser. The first operation is switched to the second operation when the physical value detected by the fan input detector is equal to or larger than a reference value. The controller adjusts the reference value so that the reference value when refrigerant flowing through the outdoor heat exchanger has a high temperature is smaller than the reference value when the refrigerant has a low temperature.

An air conditioner is provided. The air conditioner includes a display, a storage configured to store power consumption information and time information which are required to increase or decrease an indoor temperature by a unit temperature according to an outdoor temperature, a sensor, and a processor configured to predict, based on a desired temperature being input, at least one of a power consumption or a required time for the indoor temperature to reach the desired temperature by the sensor based on information stored in the storage, and provide at least one of the predicted power consumption or the required time through the display.

A system for starting a refrigeration system includes a liquid line regulating valve, a liquid line charging valve, a suction line expansion valve, a suction line charging valve, and a controller. The controller is configured to override normal operation of the refrigeration system and transmit a demand signal to enable partial system operation. The controller is configured to operate the liquid line regulating valve and the liquid line charging valve to charge a receiver tank, gradually increase the demand signal to a predetermined level of partial system operation, and release the liquid line charging valve to normal operation. The controller is configured to operate the suction line expansion valve and the suction line charging valve to charge a suction line, gradually increase the demand signal to full system operation, and release the liquid line regulating valve, the suction line expansion valve, and the suction line charging valve to normal operation.

An inverter control device that controls an inverter unit that converts a DC voltage from a converter unit to an AC voltage and supplies the AC voltage to the DC motor includes a storage unit that stores therein information regarding a synchronization-loss limit; a synchronization-loss limit-current calculation unit that calculates the limitation value on the synchronization-loss limit current on the basis of the magnet temperature of the DC motor, the bus voltage to be applied to the inverter unit, and the information regarding a synchronization-loss limit; and a control unit that compares the primary current to be input to the converter unit with the limitation value and that, when the primary current exceeds the limitation value, outputs an adjustment command to adjust the operating frequency of the DC motor such that the primary current becomes equal to or less than the limitation value.

Containers (100) for cryopreserved biological samples (102) may include an insulated housing including a cavity (108) for containing at least one cryopreserved biological sample; and a sealed reservoir (106) at least partly surrounding the cavity, the sealed reservoir including liquified gas (120) such as liquified air, the gas being kept largely liquified by a heat transfer engine (112) such as a Stirling cryocooler. A valve (114) may be provided to function as both a pressure relief valve and an inlet valve. The inlet valve may be coupled to a sensor (122) for sensing a volume of liquified gas within the sealed reservoir. The container may further include a heat exchanger (116) coupled to the heat engine and extending into the sealed reservoir.

A method for a refrigeration system includes receiving a temperature difference (TD) setpoint indicating a desired temperature difference between outside air and refrigerant and modifying the TD setpoint based on conditions currently being experienced by the refrigeration system. The modified TD setpoint is selected to cause a decrease in total power consumption, wherein the total power consumption comprises power consumed by a compressor to yield a discharge pressure and power consumed by a condenser fan to operate a fan speed.

A refrigeration system includes at least one compressor, a condenser, one or more sensors, and a controller. The one or more sensors are operable to sense data associated with the refrigeration system. The controller is operable to receive operating data associated a first control variable and a second control variable, the operating data received from the one or more sensors. The controller is further operable to determine, based on the operating data, that a control objective is not met, and operate the refrigeration system according to a configuration selected to cause the control objective to be met in response to determining that the control objective is not being met, wherein operating the refrigeration system according to the configuration selected to cause the control objective to be met comprises overriding control of the second control variable until the control objective is met.

A free piston Stirling refrigerator of the present invention has a cylinder provided inside a casing; a piston and a displacer that are provided in a way such that they are capable of reciprocating inside the cylinder; a linear motor for reciprocating the piston; and a control unit for controlling the operation of the linear motor. Particularly, the control unit has an inverter circuit for generating an alternating current with a given frequency and then supplying the alternating current to the linear motor; a current detection circuit for detecting the current outputted from the inverter circuit; and a control circuit for controlling the output from the inverter circuit based on a turbulence in the current detected by the current detection circuit. Thus, collisions between the piston and the displacer (i.e. hitting) can be restricted through an inexpensive configuration and a simple control.

A system is configured to remotely determine characteristics of a local operating environment of an outdoor condenser unit. The system includes a detector configured to sample power consumption of the condenser unit to obtain a sampled power consumption time series. An analyzer receives the sampled time series of the detector and determines characteristics of a local operating environment of the condenser unit from the power consumption time series. The analyzer generates an output that includes information about the local operating environment.