A system for monitoring and reporting internal refrigeration unit temperatures includes a temperature measuring device for placement within the refrigeration unit. The temperature measuring device has a first temperature sensors situated in a liquid or solid mass (e.g. glycol or glass beads) for measuring an average temperature within the refrigeration unit and/or has a second temperature sensors exposed to ambient air within the refrigeration unit for measuring an instantaneous temperature within the refrigeration unit. A circuit periodically transmits the average temperature and/or the instantaneous temperature from the temperature measuring device to a server where the average temperature and the instantaneous temperature are analyzed to determine and/or predict a fault with the refrigeration unit. Upon determination and/or prediction of the fault, an alert is sent to at least one staff member indicating the refrigeration unit and fault.

A system and method for a compressor includes a compressor connected to a condenser, a discharge line temperature sensor that outputs a discharge line temperature signal corresponding to a discharge line temperature of refrigerant leaving the compressor, and a control module connected to the discharge line temperature sensor. The control module determines a saturated condenser temperature, calculates a discharge superheat temperature based on the saturated condenser temperature and the discharge line temperature, and monitors a flood back condition of the compressor by comparing the discharge superheat temperature with a predetermined threshold. The control module increases a speed of the compressor when the discharge superheat temperature is less than or equal to the predetermined threshold.

An air conditioner according to an embodiment includes: a compressor configured to compress a refrigerant; an indoor heat exchanger configured to convert a vapor refrigerant into a liquid refrigerant in a heating mode; an outdoor heat exchanger configured to convert a liquid refrigerant into a vapor refrigerant in the heating mode; a main pipe connecting the indoor heat exchanger to the outdoor heat exchanger; an injection pipe branching from the main pipe and connecting to an injection port of the compressor; an injection valve installed on the injection pipe and configured to control a flux of the refrigerant flowing to the injection pipe; and a controller configured to calculate a target discharge superheat (DSH) based on a correlation between a compression coefficient, a compressor frequency, and a DSH that are represented by an operating condition , and control a current DSH based on the target DSH.

Systems and methods for controlled subcooling of working fluid in a heating, ventilation, air conditioning and refrigeration (HVACR) system through a suction line heat exchanger are disclosed. The suction line heat exchanger may receive a first fluid flow travelling to a suction of the compressor in the HVACR system and second flow of working fluid that is travelling from a heat exchanger receiving the discharge of the compressor to an expansion device. Superheating of the first working fluid may be determined based on temperature measurements prior to and following the suction line heat exchanger. The superheating may be used to control the quantity of the second flow of working fluid introduced into the suction line heat exchanger, for example to maintain superheat that is below a threshold value. These systems may include chillers and heat pump systems, and methods may be applied to chillers or heat pump systems.

A driving apparatus includes: an inverter unit generating a three-phase alternating-current voltage from a direct-current voltage in accordance with a drive signal based on a voltage command and outputting the three-phase alternating-current voltage to a permanent-magnet motor, the permanent-magnet motor including a permanent magnet; a current detection unit detecting a motor current flowing through the permanent-magnet motor; and a control unit generating the voltage command to control an operation of the inverter unit and estimating a temperature of the permanent magnet to perform a protection operation on the inverter unit on the basis of the motor current and an overcurrent protection threshold. The control unit sets the overcurrent protection threshold on the basis of a magnet temperature estimated value of the permanent magnet and any one of a control computation period of the control unit, an output voltage frequency of the inverter unit, and a carrier frequency based on the output voltage frequency of the inverter unit.

A method operates an absorption heat pump system, specifically the flow of hydronic cooling fluid through the condenser during system start-ups, or when the cooling fluid temperature is low. To minimize the time for an absorption heat pump to reach full cooling or heating capacity, it is desirable for the high side pressure to increase as fast as possible, and the low side pressure to decrease as fast as possible. Since the high side pressure is a function of the temperature of the refrigerant exiting the condenser, if the condenser cooling fluid temperature is low, the corresponding high side pressure will be low, which may not permit adequate working fluid flow rates from the high pressure side of the system to the low pressure side.

A method of cooling a motor coupled to a compressor of a chiller includes adjusting a position of a motor cooling valve located fluidly between the motor and a refrigerant source, using a motor temperature control system coupled to the motor cooling valve to regulate an amount of refrigerant introduced into the motor from the condenser according to a temperature control scheme performed as a function of a monitored temperature in the motor, a first temperature threshold, and a second temperature threshold lower than the first temperature threshold. The temperature control scheme includes a motor cooling control process that adjusts the position of the motor cooling valve based on a stator winding temperature set point relating to stator windings of the motor. A proportionally limited close command override associated with a first temperature range above the second temperature threshold proportionally limits a close command provided to the motor cooling valve.

A refrigeration cycle apparatus includes a refrigerant circuit and a controller for controlling the refrigerant circuit. The refrigerant circuit includes a compressor, a condenser, a pressure-reducing device and an evaporator. Refrigerant circulating through the refrigerant circuit contains propane or propylene. The controller sets a degree of superheat of refrigerant at an entrance port of the compressor to be a value greater than or equal to 10 degrees.

A cooling system includes: a compressor; a condenser; an expansion valve; an evaporator; an internal heat exchanger having a first conduit in heat exchanging contact with a second conduit, the first conduit being part of a high pressure fluid line between the condenser and the expansion valve, the second conduit being part of a low pressure fluid line between the evaporator and the compressor; a bypass line connecting the high pressure fluid line with the low pressure fluid line and for injecting small amounts of liquid fluid from the high pressure fluid line into the low pressure fluid line; a valve arranged in the bypass line for opening and closing the bypass line; and a control device for monitoring a load point of the compressor and controlling the valve to an open position when the load point exceeds a threshold.

A method of cooling a motor coupled to a compressor of a chiller includes adjusting a position of a motor cooling valve located fluidly between the motor and a refrigerant source, using a motor temperature control system coupled to the motor cooling valve to regulate an amount of refrigerant introduced into the motor from the condenser according to a temperature control scheme performed as a function of a monitored temperature in the motor, a first temperature threshold, and a second temperature threshold lower than the first temperature threshold. The temperature control scheme includes a motor cooling control process that adjusts the position of the motor cooling valve based on a stator winding temperature set point relating to stator windings of the motor. A proportionally limited close command override associated with a first temperature range above the second temperature threshold proportionally limits a close command provided to the motor cooling valve.