An illustrative example refrigerant system includes a compressor configured to pressurize a refrigerant fluid. The compressor includes a sump portion. A heater is situated to heat at least the sump portion. A controller is configured to selectively operate the heater to apply heat to at least the sump portion while the compressor is off to establish and maintain a superheat condition in the compressor.

A refrigerant metering system/method incorporating a manual expansion valve (MEV), condenser isolation valve (CIV), flow isolation valve (FIV), and evaporator isolation valve (EIV) is disclosed. The MEV is configured to replace a conventional automated expansion valve (AEV) that controls a refrigerant flow valve (RFV) that is positioned in a heating, ventilation, and air conditioning (HVAC) system between a refrigerant condenser coil (RCC) and a refrigerant evaporator coil (REC) and permits manual metering of refrigerant by the RFV from the RCC to the REC and also allows complete shutoff of refrigerant flow by the RFV from the RCC to the REC. The MEV allows rapid HVAC repair and restoration of service where a replacement AEV is not readily available. The CIV/FIV/EIV are positioned in the refrigerant flow lines to permit the AEV and/or REC to be isolated from HVAC refrigerant flow for repairs to the AEV and/or REC.

A refrigerated display case having a housing defining a temperature controlled space and a refrigeration system coupled to the housing is provided. The refrigeration system is configured to be operable to affect a temperature of the temperature controlled space. The refrigeration system includes an actuator, a controller, and a sensor. The controller is configured to continuously update a stored position of the actuator based on measurement of an electric current provided to the actuator, retrieve the stored position after a power failure, and restart control based on the stored position of the actuator. The sensor is configured to communicate with the controller.

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.

An air conditioning system including a compressor having a motor; a condenser; an evaporator; a drive providing multiphase, AC output to the motor; a motor braking assembly electrically connected to the drive, the motor braking assembly including at least one switch and at least one braking resistor; wherein the at least one switch is held in an open state by power from the drive; wherein upon disruption of power to the motor, the at least one switch assumes a closed state shorting windings of the motor through the at least one braking resistor.

A refrigeration cycle apparatus is a refrigeration cycle apparatus having a refrigerant circuit having a compressor, a condenser, a supercooler, an expansion device, and an evaporator connected by a refrigerant pipe, and configured to circulate refrigerant containing refrigerant having a temperature gradient, wherein the supercooler sets a degree of supercooling of the refrigerant, which is a temperature difference between a temperature from the condenser to a refrigerant flow inlet of the supercooler and a temperature in a refrigerant flow outlet on a downstream side of the supercooler, to be larger than the temperature gradient generated at a time of refrigerant shortage of the refrigerant between the refrigerant flow inlet and the refrigerant flow outlet of the supercooler, the refrigeration cycle apparatus including a refrigerant amount determination unit configured to compare a determination threshold value set to a value larger than the temperature gradient of the refrigerant with the degree of supercooling of the refrigerant, and determine whether or not there is a shortage of a refrigerant amount filled in the refrigerant circuit.

An air conditioning apparatus includes an electric compressor, an inverter, a temperature detection element, and an ECU. The electric compressor compresses a refrigerant drawn from a refrigerant intake port and discharges the refrigerant from a refrigerant discharge port. The inverter is integrated with the electric compressor so as to be cooled by the drawn refrigerant, and operates the electric compressor according to a control signal. The temperature detection element detects a temperature of the inverter. The ECU outputs a control signal to control the inverter. The ECU performs any one or both of a control for reducing a self-cooling amount of the electric compressor and a control for increasing a self-heat generation amount of the inverter with respect to the inverter when the temperature detected by the temperature detection element is lower than a predetermined reference temperature.

An air-conditioning apparatus includes a refrigerant circuit formed by connecting a compressor that discharges a zeotropic refrigerant, an outdoor-side heat exchanger that exchanges heat between outside air and the refrigerant, a first expansion device that regulates the pressure of the refrigerant, and a load-side heat exchanger that exchanges heat between the air in an air-conditioning target space and the refrigerant. The air-conditioning apparatus includes a controller that has a composition computing function unit and a composition determining function unit The composition determining function unit is configured to adopt a predetermined value set in advance and related to composition as a circulating composition if the computation result is determined as incorrect, and adopt the computation result as the circulating composition if the computation result is determined as correct.

According to one embodiment, a refrigeration cycle apparatus, a fusible plug is attached to a low-pressure-side pipe between an evaporator and a compressor. The refrigeration cycle apparatus includes a heat quantity reduction member. The fusible plug fuses when a temperature of heat transmitted from the low-pressure-side pipe to the fusible plug reaches a predetermined value or more, and then opens the inside of the low-pressure-side pipe to atmosphere. The heat quantity reduction member reduces the quantity of heat to be transmitted to the fusible plug.

An example transport refrigeration system includes first and second refrigeration circuits configured to cool first and second transport compartments, respectively. An electric machine powers the first and second refrigeration circuits. A controller is configured to monitor a temperature of the electric machine, and reduce a cooling capacity of a selected one of the first and second refrigeration circuits based on the temperature exceeding a first threshold.