Heat pump motor optimization and sensor fault detection
AssigneeCopeland Corporation
InventorsVijay Bahel, Hank Millet, Mickey Hickey, Hung Pham, Gregory P. Herroon, Wayne R. Warner, Jean-Luc M. Caillat
Life of this patent
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Abstract
The microprocessor-based HVAC control system detects sensor faults by comparing thermistor readings with predetermined extreme values, indicative of sensor fault. The system automatically selects the appropriate combination of automatic/preset modes of operating key system components such as the expansion valve, the demand defrost system and the indoor fan speed control system. With a view towards minimizing any negative impact on system performance and reliability in the event of sensor malfunction.
Claims15
In a heat pump system including a refrigerant compressor and an electrically controlled expansion valve, a system operating method comprising,
- obtaining a discharge temperature by measuring a property indicative of the temperature of refrigerant discharged from the compressor;
- comparing the discharge temperature with a predetermined temperature indicative of an alert condition;
- based on said comparing step:
- (a) if the discharge temperature is above said predetermined temperature, using the discharge temperature to control the setting of said expansion valve, and
- (b) if the discharge temperature is not above said predetermined temperature, setting said expansion valve to a predetermined setting.
In a heat pump system including a refrigerant compressor and an electrically controlled expansion valve, a system operating method comprising,
- obtaining a discharge temperature by measuring a property indicative of the temperature of refrigerant discharged from the compressor;
- obtaining an outdoor air temperature by measuring a property indicative of the outdoor air temperature;
- comparing the discharge temperature with a predetermined temperature indicative of an alert condition;
- comparing the outdoor air temperature with a second predetermined temperature indicative of a second alert condition;
- and
- based on said comparing steps:
- (a) if said outdoor air temperature is above said second predetermined temperature and if said discharge temperature is above said predetermined temperature, then controlling said expansion valve to increase refrigerant flow, and
- (b) if said discharge temperature is not above said predetermined temperature,
- setting said expansion valve to a predetermined setting.
In a heat pump system including a refrigerant compressor and an electrically controlled expansion valve, a system operating method comprising,
- obtaining a discharge temperature by measuring a property indicative of the temperature of refrigerant discharged from the compressor;
- obtaining a line voltage measurement by measuring a property indicative of line voltage;
- comparing the discharge temperature with a predetermined temperature indicative of an alert condition;
- comparing the line voltage to a predetermined nominal voltage;
- and based on said comparing steps:
- (a) if said discharge temperature is above the said predetermined temperature and if said line voltage measurement is below said predetermined nominal voltage,
- then controlling said expansion valve to increase refrigerant flow, and
- (b) if said discharge temperature is not above said predetermined temperature,
- setting said expansion valve to a predetermined setting.
Dependencies are inferred from the claim text.