Carrier Corporation

Ba-Tung Pham

Philippe Rigal

Michel Karol Grabon

Pierre Delpech

Michal Karol Grabon

Cretin Pascal

Michal K Grabon

An apparatus for managing refrigerant charge in an air conditioning unit comprising a cooling circuit through which a refrigerant flows from a compressor, through a condenser, and through an evaporator, a heat recovery circuit extending from a first terminus between the compressor and the condenser to a second terminus between the evaporator and the condenser, a heat recovery unit located between the first and second terminus of the heat recovery circuit, a first valve located between the condenser and the first terminus, a second valve located between the first terminus and the heat recovery unit, a third valve located on a cooling charge circuit having a first end on the cooling circuit between the condenser and the evaporator and a second end at the evaporator, a fourth valve located on a heating charge circuit having a first end on the heat recovery circuit and a second end at the evaporator, and a logic unit for sensing a saturated temperature and opening and closing the valves based upon the saturated temperature to manage the refrigerant charge.

Charge management for 100% heat recovery units

A method for controlling load capacity in an air conditioning unit comprising the steps of initializing a saturated condensing temperature upper bound (SCT_UP), comparing a saturated condensing temperature (SCT) to a maximum condensing temperature threshold (MCT_TH), unloading a single load capacity step, allowing the air conditioning unit to stabilize, and setting the SCT_UP equal to the SCT after the unloading, and increasing the load capacity by one capacity step if increased load capacity is required, the SCT is less than or equal to the MCT_TH, and the SCT&#x3c;the SCT_UP.

Method to control high condenser pressure

An expansion valve is controlled in response to sensing conditions at the outlet of at least one compressor within a refrigeration loop in a manner that achieves low suction superheat operation of the compressor. In particular, a discharge superheat is computed using data obtained from a specific mathematical model of the compression process corresponding to the current capacity stage of the compressor. The position of the expansion valve is controlled so as to result in an actual discharge superheat being within a predetermined dead band amount of the computed discharge superheat.

Expansion valve control

An electronic expansion valve (EXV) used in a refrigeration cycle for a heat pump or chiller is controlled to maintain minimum pinch for ensuring proper flooded cooler exchange performance by monitoring the delta temperature between the cooler fluid and the saturated suction temperature. The discharge superheat is monitored to protect the compressor from liquid slugging. If the discharge superheat is lower than the expected value, the EXV opening is adjusted. A controller monitors certain system variables which are used to determine the optimal position of the EXV to optimize the system performance, the proper discharge superheat value, and the appropriate refrigerant charge.

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Chassieu, France

Ba-Tung Pham