Load control system and method for regulating power supply to a thermostat
First Claim
1. A system for controlling a load control relay (LCR) for a heating, ventilating, and air conditioning (HVAC) system, the system comprising a controller programmed to:
- measure a thermostat delay time of a thermostat of the HVAC system, the thermostat delay time comprising an amount of time between restoring the LCR and receiving power in a load control line coupled between the thermostat and a load of the HVAC system;
calculate a new cycle shed time and a new cycle restore time based on the measured thermostat delay time, wherein the new cycle shed time and the new cycle restore time compensate for the thermostat delay time; and
control the LCR according to the new cycle shed time and new cycle restore time.
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Accused Products
Abstract
A system for controlling a load control relay (LCR) supplying power to a thermostat of a heating, ventilating, and air conditioning (HVAC) system includes a controller programmed to maximize the amount of time that a load of the HVAC system may receive power. The controller operates by measuring a thermostat delay time of the thermostat and modifying cycle shed and restore times for controlling the LCR based on the measured thermostat delay time. By controlling the LCR according to the modified cycle shed and restore times, the controller compensates for the thermostat delay time, and the load is able to be active for a longer period of time than it otherwise would be when operating under demand-response controls.
15 Citations
20 Claims
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1. A system for controlling a load control relay (LCR) for a heating, ventilating, and air conditioning (HVAC) system, the system comprising a controller programmed to:
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measure a thermostat delay time of a thermostat of the HVAC system, the thermostat delay time comprising an amount of time between restoring the LCR and receiving power in a load control line coupled between the thermostat and a load of the HVAC system; calculate a new cycle shed time and a new cycle restore time based on the measured thermostat delay time, wherein the new cycle shed time and the new cycle restore time compensate for the thermostat delay time; and control the LCR according to the new cycle shed time and new cycle restore time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of controlling a load control relay (LCR) for a heating, ventilating, and air conditioning (HVAC) system having a thermostat and a load control line coupling the thermostat to a load, the method comprising:
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measuring a thermostat-induced delay between a time the LCR is restored and a time power is received on the load control line; defining a compensation time to offset the thermostat-induced delay; calculating a new cycle shed time and a new cycle restore time based on the compensation time; and controlling the LCR according to the new cycle shed time and the new cycle restore time. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A load control system for selectively supplying power to a thermostat of a heating, ventilating, and air conditioning (HVAC) system, the load control system comprising:
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a load control relay (LCR) coupleable to the HVAC system; a sensor configured to sense whether a load control line for a load of the HVAC system is active; a communication system capable of communicating with a master station to receive a control command comprising a shed percentage and one of a control duration and a cycle period for controlling the LCR; and a controller for selectively controlling the LCR according to the control command, the controller programmed to; calculate a cycle shed time and a cycle restore time based on the control command; control the LCR according to the cycle shed time and the cycle restore time; determine a thermostat delay between a restore time of the LCR and a time the sensor senses that the load control line is active; modify the cycle shed time and the cycle restore time based on the thermostat delay to counteract the thermostat delay; and control the LCR according to the modified cycle shed time and the modified cycle restore time. - View Dependent Claims (17, 18, 19, 20)
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Specification