Methods and systems for operating hvac systems in low load conditions
AssigneeLennox Industries Inc.
InventorDer-Kai Hung
Life of this patent
Estimating the term…
Abstract
A system comprising a compressor, a first valve coupled to the compressor and coupled to a first coil, a first expansion valve coupled to the first coil, a second coil, and a second expansion valve. The second expansion valve coupled to a third coil, a second valve coupled to the compressor and the third coil. A controller operable to operate the first valve, the first expansion valve, the second expansion valve, and the second valve. The second coil is coupled to the compressor and the refrigerant flows from the second coil to the compressor.
Claims20
A method of operating a variable refrigerant flow (VRF) system, the method comprising:
- determining that a cooling demand of the VRF system is below a threshold cooling demand;
- in response to determining that the cooling demand is below the threshold cooling demand, generating an artificial cooling load, wherein generating the artificial load comprises:
- operating a first valve to direct refrigerant discharged from a compressor only into a first coil;
- operating a first expansion valve to direct an amount of the refrigerant received from the first coil to a second expansion valve;
- operating the second expansion valve to direct the amount of the refrigerant to a third coil;
- and
- operating a second valve to direct the amount of refrigerant to flow from the third coil to the compressor.
A method of operating a variable refrigerant flow (VRF) system, the method comprising:
- determining that a cooling demand of the VRF system is below a threshold cooling demand;
- in response to determining that the cooling demand is below the threshold cooling demand, generating an artificial cooling load, wherein generating the artificial load comprises:
- operating a first valve to direct refrigerant discharged from a compressor only into a first coil;
- operating a first expansion valve to direct an amount of the refrigerant received from the first coil to a second coil, wherein the second coil is coupled to the compressor and the first amount of the refrigerant flows from the second coil to the compressor.
A variable refrigerant flow (VRF) system, the system comprising:
- a compressor operable to compress refrigerant;
- a first valve positioned between and coupled to the compressor and a first coil;
- a first expansion valve positioned between and coupled to a second expansion valve, the second expansion valve positioned between and coupled to a third coil;
- a second valve positioned between and coupled to the compressor and the third coil;
- and
- a controller, wherein, in response to determining that a cooling demand of the VRF system is below a threshold cooling demand, the controller is operable to generate an artificial load by:
- operating the first valve to direct refrigerant discharged from the compressor only into the first coil;
- operating the first expansion valve to direct an amount of the refrigerant received from the first coil to the second expansion valve;
- operating the second expansion valve to direct the amount of the refrigerant to the third coil;
- and
- operating the second valve to direct the amount of refrigerant to flow from the third coil to the compressor.
Dependencies are inferred from the claim text.