An air conditioner is provided with a refrigerant circuit that has a first refrigerant path to which a compressor, a first utilization-side heat exchanger, a first expansion valve, and a heat source-side heat exchanger are connected in order. A control unit controls the compressor and the first expansion valve. When the control unit receives a request for high-temperature air that temporarily increases the temperature of the hot air blown out through the first utilization-side heat exchanger, the control unit changes the control of the first expansion valve so that the temperature of a refrigerant that flows through the first utilization-side heat exchanger increases.

The invention belongs to the technical field of vending machines and provides a vending machine refrigeration module, including a compressor, an evaporator, a condenser controller and a temperature sensor. The temperature sensor feeds back a detected temperature value to the controller. The detected temperature value is compared with a set temperature value to automatically adjust the motor speed of the compressor, the fan speed of the evaporator, and the fan speed of the condenser. The refrigeration module provided by the invention can automatically adjust the rotation speed of the compressor motor, the evaporator fan and the condenser fan according to the temperature detected by the temperature sensor, thereby avoiding full speed operation and reducing energy consumption and avoiding energy waste, improving energy efficiency.

An air conditioner system is disclosed. The air conditioner system includes: a compressor; a four-way valve configured to provide a refrigerant circulation path depending on an operation mode of the air conditioner system; a blocking valve disposed between the compressor and the four-way valve; a circulation line configured to provide a path for introducing a refrigerant discharged from the compressor back into the compressor, when the blocking valve is in a closed state; and a controller configured to control the blocking valve based on a pressure of the refrigerant discharged from the compressor.

A refrigerant amount management system manages an amount of refrigerant with which a plurality of refrigeration cycle apparatuses is filled. Each refrigeration cycle apparatus has a refrigerant circuit. The refrigerant amount management system includes an additional-filling-amount obtaining unit that obtains an additional filling amount of refrigerant with which a refrigeration cycle apparatus has been additionally filled after installation, a storage unit, and a useful-information creation unit. The storage unit stores apparatus information regarding the refrigeration cycle apparatus that has been additionally filled with refrigerant and the additional filling amount of the refrigeration cycle apparatus identified with the apparatus information in association with each other. The useful-information creation unit creates useful information to be used in management of the amount of refrigerant based on the additional filling amount of one of the refrigeration cycle apparatuses and the additional filling amount of another of the refrigeration cycle apparatuses.

An HVAC system includes an evaporator. The evaporator includes a sensor configured to measure a property value (i.e., a saturated suction temperature or a saturated suction pressure) associated with saturated refrigerant flowing through the evaporator. The system includes a variable-speed compressor configured to receive the refrigerant and compress the received refrigerant. The system includes a controller communicatively coupled to the sensor and the variable-speed compressor. The controller monitors the property value measured by the sensor and detects a system fault, based on the monitored property value. In response to detecting the system fault, the controller operates the compressor in a freeze-prevention mode, which is configured to maintain the property value above a setpoint value by adjusting a speed of the variable-speed compressor. This prevents or delays freezing of the evaporator during operation of the system during the detected system fault.

A compressor (31a, 31b) and an oil separator (35a, 35b) are provided in a refrigerant circuit (20). A flow-rate regulating valve (41a, 41b) is provided in an oil return pipe (40a, 40b) for returning a refrigerating-machine oil in the oil separator (35a, 35b) to the compressor (31a, 31b). A temperature sensor (42a, 42b) is provided downstream of the flow-rate regulating valve (41a, 41b) in the oil return pipe (40a, 40b). The oil-amount determiner (71a, 71b) determines whether an oil shortage state in which the amount of the refrigerating-machine oil held by the compressor (31a, 31b) is insufficient is present, on the basis of a measured value obtained by the temperature sensor (42a, 42b).

A multi-air conditioner for cooling and heating is provided to remove latent heat and sensible heat by using a single outdoor unit. The multi-air conditioner includes: at least one indoor unit installed in a room, that comprises an indoor heat exchanger and an indoor expansion valve; an outdoor unit connected to the indoor unit via a refrigerant pipeline, that comprises an outdoor heat exchanger, a plurality of compressors, an outdoor expansion valve, and a four-way valve; and a dedicated outdoor air ventilation unit connected to the indoor unit and the outdoor unit via the refrigerant pipeline, that dehumidifies and ventilates outdoor air and supplies the outdoor air to the room, wherein the outdoor unit provides a refrigerant to both the dedicated outdoor air ventilation unit and the indoor unit by controlling the compressors depending on an operation mode of the dedicated outdoor air ventilation unit and the indoor unit. Accordingly, it is possible to run an air conditioner for cooling and heating and a dedicated outdoor air conditioner simultaneously by using a single outdoor unit. Moreover, the handling of sensible and latent heats can be controlled by a single outdoor unit, thereby minimizing facility costs and enhancing control reliability.

A control circuit, a signal conversion circuit and a control method are disclosed. The control circuit includes a controller, which controls a load circuit according to a received input signal; and an enable module, which is connected to the controller and enables the controller on the basis of a frequency of the input signal, wherein the controller is caused to be in an operational state so as to control the load circuit according to the input signal when the frequency is higher than a predetermined threshold, and the controller is caused to be in a sleep state and thus not control the load circuit according to the input signal when the frequency is lower than the predetermined threshold

A method and a device for controlling a capacity change of a compressor, and a smart home appliance. The method includes: determining whether a capacity of the compressor is required to be changed; if yes, determining an intermediate frequency; changing the capacity of the compressor while maintaining the operating frequency of the compressor at the intermediate frequency; and the maintaining the operating frequency of the compressor at the intermediate frequency reduces a sudden change in output of the compressor after the changing the capacity.

A refrigerant amount management system manages an amount of refrigerant with which a plurality of refrigeration cycle apparatuses is filled. Each refrigeration cycle apparatus has a refrigerant circuit. The refrigerant amount management system includes an additional-filling-amount obtaining unit that obtains an additional filling amount of refrigerant with which a refrigeration cycle apparatus has been additionally filled after installation, a storage unit, and a useful-information creation unit. The storage unit stores apparatus information regarding the refrigeration cycle apparatus that has been additionally filled with refrigerant and the additional filling amount of the refrigeration cycle apparatus identified with the apparatus information in association with each other. The useful-information creation unit creates useful information to be used in management of the amount of refrigerant based on the additional filling amount of one of the refrigeration cycle apparatuses and the additional filling amount of another of the refrigeration cycle apparatuses.