Energy reducing retrofit method and apparatus for a constant volume hvac system
AssigneeTransformative Wave Technologies LLC
InventorsDanny Miller, Justin Sipe
Life of this patent
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Abstract
An energy-reducing method and apparatus for retrofitting a single zone, constant volume HVAC system, with or without an economizer, that provides heating, cooling, and ventilation to occupants within a building space. The present invention includes the introduction of a programmable logic controller and variable frequency drive (VFD) that takes control of the existing fan, heating, cooling, and optional economizer operation. The reduction of the fan speed in the ventilation mode when the 100% operation is not needed saves significant energy of the existing constant volume HVAC system where the fan motor is designed to run 100% of the time.
Claims4
An efficiency enhancing controller (EEC) for enhancing energy efficiency in an indoor space of a building having an occupancy that is served by a single zone, constant volume HVAC system, the EEC comprising:
- a programmable logic controller adaptable for a single zone constant volume HVAC system to receive input signals from sensors and a thermostatic device and send control heating, cooling, and ventilation instructions or an occupancy command to:
- a fan assembly of the constant volume HVAC system to ventilate an indoor space in a building, and
- a heating assembly that can send heat to the indoor space, and
- a cooling assembly that can send cooling to the indoor space;
- and
- a variable frequency drive (VFD) that receives signals from the programmable logic controller and can control the frequency of a fan motor of the fan assembly,
- wherein the programmable logic controller has the capability to reduce the fan motor speed via the VFD when the sensors indicate that the indoor space is less than fully occupied.
Dependencies are inferred from the claim text.