Load management aware fan control

Abstract

A fan-control device for overriding normal operation of a circulation fan delivering conditioned air through ductwork in an unconditioned space. The fan-control device includes a detection circuit and a fan relay. The detection circuit is configured to detect a cooling system control voltage and a cooling system control current and to output a fan control override signal when the cooling system control voltage is detected and the cooling system control current is absent.

Description

FIELD OF THE INVENTION[0001]The present invention relates generally to management of electrical loads. More particularly, the present invention relates to control of circulation fans in a load-managed system for conditioning air.BACKGROUND OF THE INVENTION[0002]To manage electricity usage during times of peak demand, utility companies enroll consumers in load management, or load-shedding, programs. Participants of load-management programs agree to allow utility companies to reduce their power consumption by controlling operation of high-energy usage appliances such as air conditioners, hot water heaters, pool heaters and so on. Control of such appliances may be accomplished through the use of a controller integrated into, or cooperating with, a utility meter, thermostat, load-control device, or other such device.[0003]One of the most common high-energy-consuming appliances targeted for load control is a compressor of an air-conditioner. In a traditional forced-air heating and coolin...

AI Technical Summary

Benefits of technology

[0013]In some embodiments, the fan relay is configured to receive the fan control override signal from the detection circuit and to break an electrical connection between a thermostat of the HVAC system and the fan in response to the fan control override signal, thereby overriding normal control of the fan by the thermostat and preventing operation of the fan and circulation of unconditioned air when the load-management device is activated.

[0015]In yet another embodiment, the present invention comprises a method of optimizing cooling efficiency when managing multiple electrical loads of cooling systems of buildings included in a load-management program, at least some of the cooling systems including above-ground ductwork. The method includes providing a load-management device to each of a plurality of buildings having cooling systems, providing a fan control device to the at least one of the plurality of buildings including the cooling system having above-ground ductwork, and transmitting a load-management command to the plurality of load-management devices, the command causing each of the load-management devices to interrupt power to the compressor and unconditioned air from being distributed through the above-ground ductwork in that building.

[0016]Each of the load-management devices of this method is configured to cause power to a compressor of the cooling system to be interrupted in response to a load-management command, and at least one of the plurality of buildings includes a cooling system having above-ground ductwork for distributing conditioned air. Further, the fan control device is configured to communicate with the load-management device provided to the building and to prevent operation of a circulation fan when power to the compressor is interrupted.

Problems solved by technology

However, in those buildings having air ducts located primarily in uncooled attic spaces, the continued operation of the circulation fan may cause the temperature of the space to be cooled to rise relatively quickly, especially in very hot weather conditions.

This accelerated warming effect is especially problematic in high-temperature climates, such as those in the southern and western parts of the United States.

While installing such relatively extensive and complex networks into a building to directly control all appliances, including a circulation fan, may be one way to avoid the accelerated warming effect described above, this option remains relatively expensive and often impractical.

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