A method for operating a cooling circuit. It is provided that a) the actuation signal ST of the coolant compressor is provided so as to increase over time from a minimum value (ST.sub.min) in order to generate a start-up phase of the coolant compressor, b) a control signal maximum value (ST.sub.max) and a control signal threshold (ST.sub.SW) are provided, where ST.sub.SW<ST.sub.max, c) the actuation signal (ST) is limited to the control signal maximum value (ST.sub.max) if the actuation signal (ST) reaches the control signal threshold (ST.sub.SW) and the measured high and/or low-pressure value (PHD, P.sub.ND) satisfies a condition.

A refrigerant control system includes: a charge module configured to determine an amount of refrigerant that is present within a refrigeration system of a building; a leak module configured to diagnose that a leak is present in the refrigeration system based on the amount of refrigerant; and at least one module configured to take at least one remedial action in response to the diagnosis that the leak is present in the refrigeration system.

A dynamic refrigeration system may automatically, at pre-determined time periods on-the-fly, adjust a refrigerant system's refrigerant pressures to predetermined optimal efficiency pressures as the internal and external heat loads change over a range. This may result in the refrigerant system pressures closely operating within a range of predetermined optimal efficiency pressures. This system may automatically instantaneously fine tune and balance on all air conditioning, heat pump, and refrigeration systems as the internal and external heat loads are continuously changing dynamically. The system may include a small liquid refrigerant pump and refrigerant storage tank, one or more wired or wireless pressure transducers and temperature sensors, and a “brain” to make decisions to keep the system instantaneously set at factory specs all the time. The system may include a wireless communication means so it can instantaneously report its operating condition, loads, and cost of operating.

A system for starting a refrigeration system includes a liquid line regulating valve, a liquid line charging valve, a suction line expansion valve, a suction line charging valve, and a controller. The controller is configured to override normal operation of the refrigeration system and transmit a demand signal to enable partial system operation. The controller is configured to operate the liquid line regulating valve and the liquid line charging valve to charge a receiver tank, gradually increase the demand signal to a predetermined level of partial system operation, and release the liquid line charging valve to normal operation. The controller is configured to operate the suction line expansion valve and the suction line charging valve to charge a suction line, gradually increase the demand signal to full system operation, and release the liquid line regulating valve, the suction line expansion valve, and the suction line charging valve to normal operation.

A system for assessing and servicing a vehicle refrigeration system includes at least one sensor and at least one user device communicatively coupled to the at least one sensor. The at least one sensor is configured for attachment to an air vent portion of a vehicle, and is configured to collect at least one measurement. The at least one user device is configured to receive the at least one measurement, process the at least one measurement and generate at least one result, and display the at least one result.

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 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.

A heating, ventilation, and air conditioning (HVAC) system includes an expansion device disposed between a condenser and an evaporator of a vapor compression system and a control panel communicatively coupled to the expansion device. The control panel is configured to: determine a liquid refrigerant level set point of the condenser based on parameters of the vapor compression system, provide a first control signal to increase an opening of the expansion device in response determining that the current liquid refrigerant level in the condenser is greater than a determined liquid refrigerant level set point of the condenser, and provide a second control signal to decrease the opening of the expansion device in response to determining that the current liquid refrigerant level in the condenser is less than the determined liquid refrigerant level set point of the condenser.

Embodiments relate generally to subcooling control of a heating, ventilation, and air conditioning (HVAC) system. An HVAC system may include a compressor, a first heat exchanger, a refrigerant vessel having an inlet fluidly coupled to a discharge conduit extending from the compressor, and the refrigerant vessel having an outlet fluidly coupled to a liquid conduit, the liquid conduit configured to pass liquid refrigerant between the first heat exchanger and a second heat exchanger. The HVAC system may further include an electronic expansion valve (EEV) fluidly coupled between the discharge conduit and the inlet of the refrigerant vessel, wherein the EEV is configured to modulate and divert a portion of vapor refrigerant flowing through the discharge conduit into the refrigerant vessel to control subcooling (SC) produced by the HVAC system.

An air conditioner is provided, which is capable of accurately determining appropriateness of a refrigerant amount in a refrigerating cycle. A control apparatus is configured to: stop a cooling operation; set an expansion valve to a fully-closed state and, at the same time, switch the selector valve to change the direction, in which a refrigerant flows, to an opposite direction; operate a compressor to perform a refrigerant recovery operation, in which a refrigerant contained in an outdoor heat exchanger is recovered by an indoor heat exchanger; and determine the appropriateness of a refrigerant amount in a refrigerating cycle, based on at least one of a time required for recovering the refrigerant, a pressure change in a refrigerant suctioned by the compressor, and temperature of the refrigerant discharged from the compressor during the refrigerant recovery operation.