There is provided a HVAC system comprising: a fluid circuit for conveying a refrigerant; a compressor for compressing the refrigerant; three heat exchangers defining an evaporator, an outdoor exchanger and a heat recovery exchanger provided along the fluid circuit; an expansion valve provided along the fluid circuit; and a receiver connected in parallel to the expansion valve, wherein a fill valve is located between the receiver and a connection upstream of the expansion valve and a drain valve is located between the receiver and a connection downstream of the expansion valve; wherein the fluid circuit comprises a plurality of valves which are configured to be controlled based on a selected operating mode such that at least one of the outdoor exchanger and the heat recovery exchanger is connected to a discharge line of the compressor and in series with one of the other heat exchangers which is connected to a suction line of the compressor, with the expansion valve disposed between the heat exchangers; wherein the fill and drain valves are configured to be controlled to store a volume of refrigerant in the receiver so as to provide an effective refrigerant charge in the fluid circuit that corresponds to the selected operating mode.

A system for measuring and recharging an air conditioning system includes a vent sensor configured to be coupled to an outlet vent of an air conditioning system. The vent sensor is configured to measure at least one parameter of an air flow from the outlet vent. A processor is in signal communication with the vent sensor. The processor is configured to receive the at least one parameter of the air flow and determine a current refrigerant level of the air conditioning system.

An air conditioner has a refrigerant circuit filled with a predetermined amount of a refrigerant, the circuit being formed of an outdoor unit and an indoor unit connected to each other by refrigerant piping, the outdoor unit having a compressor, an outdoor heat exchanger, and an expansion valve, the indoor unit having an indoor heat exchanger. The conditioner has an estimation model that estimates an amount of remaining refrigerant remaining in the circuit by using at least rotation frequency of the compressor, refrigerant discharge temperature at the compressor, heat exchanger temperature, degree of opening of the expansion valve, and outside air temperature, of operation state quantities indicating operation states during operation. The indoor heat exchanger has a sensor that is provided at an indoor heat exchanger intermediate portion connecting a first indoor heat exchanger port and a second indoor heat exchanger port to each other.

A method of judging lack-of-freon in an air conditioner and an air conditioner control method. The control method includes: acquiring outflow air temperatures at the first air outlet and the second air outlet, and calculating a temperature difference; comparing the temperature difference with a preset temperature difference threshold; and adjusting an opening degree of the expansion valve accordingly. In the method, the opening degree of the expansion valve can be automatically adjusted according to a result of temperature comparison to compensate for the flow rate of freon, so as to improve the cooling or heating efficiency of the air conditioning system and realize the adaptive adjustment of the air conditioner, thereby ensuring the cooling or heating efficiency of the system even if the system lacks freon to a slight extent and effectively reducing energy consumption. The judging method has a higher accuracy of judging result, and is easier to implement.

Disclosed is a refrigerant charge management device comprising a refrigerant charge vessel enclosing a volume, a movable impervious barrier separating the volume into a first volume and a second volume, a first port disposed in fluid communication with the first volume and configured for fluid connection to a heat pump system, and a second port disposed in fluid communication with the second volume and configured for fluid connection to the heat pump system, wherein the movable impervious barrier is configured to move in response to a difference in pressure between the first volume and the second volume thereby changing the size of the first volume and the second volume.

An air-conditioning apparatus includes a compressor, an indoor heat exchanger, a first outdoor heat exchanger and a second outdoor heat exchanger, a valve between the second outdoor heat exchanger and the indoor heat exchanger switching between an opened state and a closed state, a temperature sensor detecting a temperature of refrigerant that flows into the second outdoor heat exchanger and liquefies, and a condensing-temperature detection device, wherein during first cooling operation in which the first outdoor heat exchanger functions as a condenser, the indoor heat exchanger functions as an evaporator, and the valve is in the closed state, when a comparative temperature becomes equal to or higher than a prescribed temperature, the air-conditioning apparatus switches to second cooling operation in which the valve is brought into the opened state, the comparative temperature being a value obtained by subtracting a temperature detected by the temperature sensor from the condensing temperature.

An air conditioner including: a compressor; a heat exchanger fluidly connected to the compressor; a pressure sensor provided in a first flow path connecting an outlet of the compressor to an inlet of the first heat exchanger; a temperature sensor provided in a second flow path connected to an outlet of the heat exchanger; and a processor connected to the compressor, the pressure sensor, and the temperature sensor. The processor configured to: acquire a reference index value based on a first reference pressure measured by the pressure sensor and a first reference temperature measured by the temperature sensor, acquire a measurement index value based on a first measurement pressure measured by the pressure sensor and a first measurement temperature measured by the temperature sensor, and display a shortage of a refrigerant of the air conditioner based on the reference index value and the measurement index value.

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.

A refrigerant-amount determination kit includes a sensor and a processor. The sensor is mounted at least temporarily on at least one of a portion of a refrigeration cycle apparatus and the periphery of the refrigeration cycle apparatus. The refrigeration cycle apparatus is an apparatus having a refrigerant circuit that includes a compressor, a condenser, and an evaporator. The processor determines the amount of a refrigerant in the refrigerant circuit based on a detection result detected by the sensor during operation of the refrigeration cycle apparatus.

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.