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US 10,520,235 B2Granted
Method to avoid fan cycling during low ambient operation
AssigneeLennox Industries Inc.
InventorsDavid Mackey, Aylan Him, Zer Kai Yap
Life of this patent
Estimating the term…
Abstract
A system based on temperature and/or pressure switches connected to a fan controller. An HVAC circuit includes at least one condenser coil with a plurality of tubes, one or more stages coupled to one or more compressors, at least one temperature sensor, at least one fan configured to provide airflow across the plurality of tubes, and a controller. Instead of cycling the fan off and on, fans associated with the condenser are kept running at a low speed.
Claims16
An HVAC circuit comprising:
- at least one condenser coil comprising a plurality of tubes configured to allow refrigerant to circulate, and comprising one or more stages coupled to one or more compressors, wherein the at least one condenser coil is fluidly coupled to other components of the HVAC circuit;
- at least one temperature sensor;
- at least one fan configured to provide airflow across the plurality of tubes;
- and
- a controller configured to control the speed of the at least one fan and to receive temperature measurements from the at least one temperature sensor, the controller further configured to determine a minimum fan speed based on a measured temperature and to direct the at least one fan to spin at a rate greater than or equal to the minimum fan speed when the measured temperature is less than a predetermined temperature, wherein, when the refrigerant circulates through at least a portion of the plurality of tubes of the at least one condenser coil, the minimum fan speed is greater than zero rotations per minute.
2 more elements
An HVAC refrigeration circuit comprising:
- a condenser coil comprising a liquid line and a plurality of tubes configured to allow refrigerant to circulate, and comprising first, second and third stages, wherein each stage is coupled to a respective compressor;
- at least one temperature sensor;
- at least one pressure sensor coupled to the liquid line of the condenser coil;
- at least one fan configured to provide airflow across the plurality of tubes;
- and
- a controller configured to control the speed of the at least one fan, to receive temperature measurements from the at least one temperature sensor, to receive pressure measurements from the at least one pressure sensor, and to control the activity of the first, second, and third stages and the respective compressors, the controller further configured, when a measured temperature is below a predetermined temperature, to determine a fan speed, based on the measured temperature, to maintain pressure in the liquid line within a predetermined range, and to adjust the at least one fan to the fan speed, wherein, when the refrigerant circulates through at least a portion of the plurality of tubes of the at least one condenser coil, the fan speed is greater than zero rotations per minute.
3 more elements
Dependencies are inferred from the claim text.