Patent ID: 8965586
Filing Date: 2015-02-24
Classification: F24F,G05B,G05D,H04L,Y02B

Abstract:
1. A method of reducing energy consumption by retrofitting a preexisting single zone constant volume HVAC system that provides one or more of the following: heating, cooling, or ventilation to an indoor space within a single zone of a building that has periodic occupancy, wherein the heating, cooling, or ventilation is initiated based upon preset conditions or on occupancy command and wherein the preexisting HVAC system includes a fan assembly configured to operate between no operation and a maximum ventilation with a range of operation from 0 to 100%, a thermostatic device, heating and/or cooling equipment having preexisting equipment control terminations, the energy reducing method comprising: providing a programmable logic controller that can receive input from the thermostatic device and send heating, cooling, and ventilation instructions to a preexisting fan assembly for ventilating an indoor space within a single zone of a building, and to a preexisting heating assembly that can send heat to the same indoor space, and to a preexisting cooling assembly that can send cooling to the same indoor space; and operably connecting the programmable logic controller to preexisting equipment control terminations; providing a variable frequency drive (VFD), controlled by the programmable logic controller, and operably connecting the VFD to the preexisting fan assembly; operating the preexisting HVAC system in a ventilation mode, a heating mode, and/or a cooling mode, controlled by the programmable logic controller; operating the preexisting fan assembly at a reduced speed during the ventilation mode when the less than maximum ventilation is required; and providing fault detection via a discharge air sensor or current status switch.