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.

The disclosure relates to apparatuses and methods for indicating status of multi-phase vacuum-assisted recovery of refrigerant from a vehicle. One apparatus for multi-phase vacuum-assisted recovery of refrigerant from a vehicle includes a compressor that removes refrigerant from the vehicle during a first phase and a second phase of a recovery process. The apparatus also includes a vacuum pump to assist the compressor in the removal of refrigerant from the vehicle during a second stage of the recovery process. Further, the vacuum pump is fluidly connected in series with the compressor during the second phase of the recovery process. The apparatus additionally includes one or more status lights and at least one processor to determine a status of the recovery process. At least one of the status lights is illuminated to represent a status of the recovery process, and at least one is visible from 360 degrees around the apparatus.

A dehumidification system includes a compressor, a primary evaporator, a primary condenser, a secondary evaporator, a secondary condenser, a modulating valve, and an alternate condenser. The secondary evaporator receives an inlet airflow and outputs a first airflow to the primary evaporator. The primary evaporator receives the first airflow and outputs a second airflow to the secondary condenser. The secondary condenser receives the second airflow and outputs a third airflow to the primary condenser. The primary condenser receives the third airflow and outputs a dehumidified airflow. The compressor receives a flow of refrigerant from the primary evaporator and provides the flow of refrigerant to the modulating valve. The modulating valve directs the flow of refrigerant to the primary condenser and to the alternate condenser. The alternate condenser receives a portion of the flow of refrigerant for heat rejection, where the primary condenser receives the remaining portion of the flow of refrigerant.

A method for monitoring a refrigerant charge in a vapour compression system (1) is disclosed, the vapour compression system (1) including a compressor unit (2), a heat rejecting heat exchanger (3), a high pressure expansion device (4), a receiver (5), at least one expansion device (9, 10), and at least one evaporator (11, 12) arranged in a refrigerant path. A change in net mass flow into or out of the receiver (5) and/or a change in net enthalpy flow into or out of the receiver (5) is detected, and a pressure inside the receiver (5) is monitored as a function of time, following the detected change in net mass flow and/or in net enthalpy flow. A time constant being representative for dynamics of the receiver (5) is derived, based on the monitored pressure as a function of time, and information regarding a refrigerant charge in the vapour compression system (1) is derived, based on the derived time constant.

A charge-verification system for a circuit including a condenser having an inlet, an outlet, and a coil circuit tube extending between the inlet and the outlet is provided. The charge-verification system may include a first of coil temperature sensor located on the coil circuit tube a first distance from the inlet and a second of coil temperature sensor located on the coil circuit tube a second distance from the inlet. The charge-verification system may also include a controller receiving a first signal from the first temperature sensor indicative of a first temperature and a second signal from the second temperature sensor indicative of a second temperature. The controller may determine which of the first signal and the second signal is closer to an actual saturated condensing temperature of the condenser.

The present disclosure relates to apparatuses and methods for multi-phase vacuum-assisted recovery of refrigerant from a vehicle. One apparatus for multi-phase vacuum-assisted recovery of refrigerant from a vehicle includes a compressor that removes refrigerant from the vehicle during a first phase and a second phase of a recovery process. The apparatus also includes one or more pressure sensitive devices that are each configured to measure a first pressure and/or a second pressure in the apparatus. Upon the first pressure being less than a first threshold pressure, a vacuum pump that is fluidly connected in series with the compressor assists the compressor in the removal of refrigerant from the vehicle during a second stage of the recovery process. Also, upon the second pressure being less than a second threshold pressure, the vacuum pump ceases assisting the compressor.

A method for controlling a vapor compression system during start-up is disclosed. The rate of change, ΔT.sub.1, of the temperature of refrigerant entering the evaporator, and the rate of change, ΔT.sub.2, of the temperature of refrigerant leaving the evaporator are compared. Based on the comparing step, a refrigerant filling state of the evaporator is determined. The opening degree of the expansion device is then controlled according to a first control strategy in the case that it is determined that the evaporator is full or almost full, and according to a second control strategy in the case that it is determined that the evaporator is not full. Thereby it is ensured that a maximum filling degree of the evaporator is quickly reached, without risking that liquid refrigerant passes through the evaporator.

A variable refrigerant volume system and control method thereof. The variable refrigerant volume system comprises: a compressor (1); a four-way valve (19); an indoor unit; a liquid tube (22), the first end thereof being connected to the indoor unit, the second end thereof being connected to the third valve port of the four-way valve (19), and a condenser (18) being provided on the liquid tube (22); a low pressure air pipe (23), the first end thereof being connected to the indoor unit, and the second end thereof being connected to the fourth valve port of the four-way valve (19); a refrigerant adjustment tank (6), the first port thereof being connected to the liquid tube (22), the second port thereof being connected to the low pressure air pipe (23), and the third port thereof optionally communicating with the liquid tube (22) or the low pressure air pipe (23). The refrigerant adjustment tank (6) provides refrigerant to the variable refrigerant volume system when the system requires more refrigerant, and recycles refrigerant from the variable refrigerant volume system when the system requires less refrigerant. The variable refrigerant volume system can flexibly control a refrigerant recycling amount in accordance with a refrigerant operation situation, thus ensuring system reliability.

A system for charging an outdoor unit with refrigerant includes a sensor configured to measure a refrigerant concentration and a user device configured to receive the measured refrigerant concentration. The system includes that the user device is configured to, in response to the measured refrigerant concentration exceeding a threshold, generate and display an alert on a user interface of the user device indicating the measured refrigerant concentration exceeds the threshold.

A refrigerant recovery system includes a first oil separator including a chamber configured to receive refrigerant from an air conditioning system, a heat exchanger disposed within the first oil separator, and a compressor fluidly connected to the chamber and the heat exchanger. A first valve is disposed in a first flow line that is fluidly connected between an inlet of the first oil separator and a source of refrigerant and a second valve is disposed in a second flow line that fluidly connects the compressor and the heat exchanger. A controller is configured to open the first valve to enable refrigerant to pass into the chamber of the first oil separator, open the second valve so that a flow loop for refrigerant is formed between the heat exchanger and the compressor, activate the compressor to heat the refrigerant flowing through the flow loop, and subsequently commence a refrigerant recovery operation.