A cryocooler includes a displacer, a cylinder that forms an expansion space, a Scotch yoke mechanism configured to drive the displacer in a reciprocating manner, a first rod that extends from the Scotch yoke mechanism, a housing that includes an assist chamber, a rotary valve configured to switch between a state in which the expansion space and a discharge side of a compressor are connected and the assist chamber and a suction side of the compressor are connected and a state in which the expansion space and the suction side of the compressor are connected and the assist chamber and the discharge side of the compressor are connected, a motor configured to drive the Scotch yoke mechanism and the rotary valve, and an on-off valve configured to open and close a gas flow path through which the rotary valve and the assist chamber are connected.

A packaged, pumped liquid, evaporative-condensing recirculating ammonia refrigeration system with charges of 10 lbs or less of refrigerant per ton of refrigeration capacity. The compressor and related components are situated inside the plenum of a standard evaporative condenser unit, and the evaporator is close coupled to the evaporative condenser. Single or dual phase cyclonic separators may also be housed in the plenum of the evaporative condenser.

A dynamic receiver is included in parallel to an expander of a heating, ventilation, air conditioning, and refrigeration (HVACR) system. The dynamic receiver allows control of the refrigerant charge of the HVACR system to respond to different operating conditions. The dynamic receiver can be filled or emptied in response to the subcooling observed in the HVACR system compared to desired subcooling for various operating modes. The HVACR system can include a line directly conveying working fluid from compressor discharge to the dynamic receiver to allow emptying of the dynamic receiver to be assisted by injection of the compressor discharge.

A cryocooler includes an expander provided with an expander motor including a motor rotary shaft, a displacer that changes a volume of an expansion space of a working gas by reciprocating linearly by the motor rotation shaft rotating, and a rotary valve that controls intake and exhaust of the working gas into the expansion space by rotating by the motor rotation shaft rotating, a pressure sensor that measures a pressure of the working gas and outputs a measurement signal indicating the measured pressure, and a controller that receives the measurement signal, detects a feature point appearing periodically in the measured pressure during an operation of the cryocooler, acquires a motor drive waveform indicating a command rotation speed of the motor rotary shaft determined to vary within one rotation of the motor rotary shaft, and outputs the motor drive waveform in synchronization with the feature point appearing periodically.

A refrigeration system including an evaporator defining an evaporator envelope and positionable to condition an airflow, the evaporator including an airflow inlet, an airflow outlet, and one or more refrigerant coils. The refrigeration system also includes a pressure sensor that is positioned to detect an outlet air pressure at or adjacent the outlet, and positioned to detect one or both of an ambient air pressure and an inlet air pressure and to generate a signal indicative of the corresponding air pressure. A control system in operative communication with the pressure sensor to determine a pressure differential based on the signal indicative of the outlet air pressure and the signal indicative of the ambient air pressure or the inlet air pressure, the control system configured to selectively initiate a demand defrost of the evaporator based on the determined pressure differential.

The purpose of the present invention is to provide a vehicle air conditioning system and a control method of the vehicle air conditioning system which enable detecting leaks of flammable refrigerant without requiring a separate sensor. This vehicle air conditioning system is provided with: a refrigeration cycle for cooling (23); a heat pump cycle for heating (33); a refrigerant that is very flammable, has an explosive range near room temperature, and circulates in the refrigeration cycle for cooling (23) and the heat pump cycle for heating (33); an outside temperature sensor (44) which detects the outside temperature; a pressure sensor (49) which detects the refrigerant pressure; and a control device which calculates the refrigerant density, which is the density of refrigerant, on the basis of the outside temperature and the pressure, and determines whether or not the refrigerant density has fallen below a prescribed threshold value which is based on the amount of sealed refrigerant, the total volume in the refrigeration cycle for cooling (23) and in the heat pump cycle for heating (33), the volume of the vehicle cabin, the standard density of the atmosphere, and the explosive limit of the refrigerant.

A method for determining a level of refrigerant charge in a cooling circuit of an air-conditioning system and a module for leak detection are provided. The method includes determining a total quantity of refrigerant contained in the cooling circuit of the air-conditioning system solely based on data internal to the air-conditioning system.

A HVACR protection system can include a pressure sensor to sense pressure within a refrigerant line coupled to a compressor; a timer; and a protection system controller. A compressor controller in communication with the protection system controller can control operation of the compressor and disable the compressor until successful completion of a vacuum test of the refrigerant line. The vacuum test can initiate upon the pressure sensor sensing the pressure being less than or equal to a vacuum test pressure, at which point the timer begins timing for a vacuum test time period. The vacuum test is successfully completed upon expiration of the vacuum test time period with the pressure remaining less than or equal to the vacuum test pressure for the vacuum test time period. The protection system controller can enable the compressor controller to operate the compressor upon successful completion of the vacuum test.

The present disclosure relates to a method for controlling a level of superheat during a pump mode of operation of a refrigeration system, wherein the refrigeration system can operate in either the pump mode or a compressor mode, and has an electronically controlled expansion valve (EEV). A controller obtains a stored, predetermined pump differential pressure range able to be produced by a pump of the system. The controller also obtains a stored, predetermined superheat range, and detects a superheat level. When the detected superheat level is outside of the superheat temperature range, the controller commands adjusting at least one of the EEV and a speed of the pump based on whether the detected superheat level is above or below the superheat range, and whether a current pump differential pressure is above or below the predetermined pump differential pressure range.

A refrigeration cycle apparatus includes: a compressor configured to compress refrigerant and discharge the refrigerant to a refrigerant pipe; an air heat exchanger configured to exchange heat between air and the refrigerant flowing through the refrigerant pipe; an expansion valve configured to adjust pressure of the refrigerant flowing through the refrigerant pipe; a water heat exchanger configured to exchange heat between water supplied from the water return header pipe and the refrigerant and send out the water to the water delivery header pipe; an outlet pressure sensor provided on a water outlet side of the water heat exchanger and configured to measure water pressure; and a controller, in which the controller controls an opening degree of the bypass valve such that a value of water pressure measured by the outlet pressure sensor is equal to a preset target value.