Method and apparatus for delivering conditioned air using pulse modulation
AssigneeAirFixture L.L.C.
InventorStanley J. Demster
Life of this patent
Estimating the term…
Abstract
A method and apparatus for delivering conditioned air using short duty cycles during which a damper is fully open for a time and fully closed for the remaining time. Conditioned air is continuously supplied to a plenum at low pressure and is applied to the space when the damper is open and blocked when the damper is closed. The proportion of on to off time during each duty cycle is adjusted to meet the load. When several supply terminals serve a space, their duty cycles are staggered to avoid fan instability. A special motor is coupled directly to the damper shaft for fast opening and closing of the damper. A magnetic latch holds the damper open or closed until the motor moves it again.
Claims16
A method of delivering conditioned air to a space, comprising the steps of:
- sensing a condition in the space;
- selecting a duration for a duty cycle that is less than two minutes;
- selecting a time period during each duty cycle which is dependent on the condition sensed in the space;
- applying conditioned air to the space during said time period of each duty cycle;
- and
- stopping the application of conditioned air to the space during the part of each duty cycle that does not include said time period.
Apparatus for delivering conditioned air to a space, comprising:
- a source of conditioned air,
- a terminal unit communicating with said source to receive conditioned air therefrom and apply the air to the space, said terminal unit including a damper having a fully open condition wherein conditioned air is applied to the space by said terminal unit and a closed condition wherein the flow of conditioned air from said terminal unit is blocked by said damper;
- a sensor in the space sensing a selected condition therein;
- and
- a control system having sequential duty cycles each of a selected duration, said control system being responsive to the condition sensed by said sensor to effect the fully open condition of said damper for a selected time period during each duty cycle and the closed condition of said damper for the part of each duty cycle that does not include said selected time period.
Apparatus for delivering conditioned air to a space, comprising:
- a sensor for sensing a selected condition in the space;
- a plurality of terminal units each receiving conditioned air for application to the space, said terminal units being spaced apart in the space;
- a damper for each terminal unit having a fully open condition wherein conditioned air is applied to the space and a closed condition wherein the flow of conditioned air to the space is blocked, each damper having successive duty cycles each including a selected time period dependent on the condition sensed by said sensor;
- and
- a control system for effecting the fully open condition of each damper during said selected time period of each duty cycle and the closed condition of each damper during the part of each duty cycle that does not include said selected time period, said control system initiating the duty cycles of at least one damper at a different time than the duty cycles of another of said dampers is initiated.
Apparatus for delivering conditioned air to a room having a space located above a ceiling overlying the room, said apparatus comprising:
- a source of conditioned air;
- an enclosed supply plenum located in said space immediately above the ceiling and communicating with said source to receive conditioned air therefrom;
- a terminal unit on said ceiling arranged to receive conditioned air from said supply plenum and apply the conditioned air to the room;
- a temperature sensor in said room for sensing the air temperature therein;
- a damper associated with said terminal unit having a fully open condition wherein conditioned air is applied to the room by said terminal unit and a closed condition wherein the flow of conditioned air from said terminal unit is blocked, said damper having successive duty cycles each including a selected time period dependent on the temperature sensed by said sensor;
- a control system for effecting the fully open condition of said damper during said selected time period of each duty cycle and the closed condition of said damper during the part of each duty cycle that does not include said selected time period;
- a return air plenum in said space separated from said supply plenum and communicating with said source to supply return air thereto from the room;
- and
- a return register in the room communicating with said return air plenum to supply return air thereto.
A method of delivering conditioned air to a space, comprising the steps of:
- selecting a duty cycle having a fixed duration comprising a first time period and a second time period together occupying the entirety of said fixed duration;
- sensing a condition in the space;
- setting said first time period according to the condition sensed in the space;
- applying conditioned air to the space during said first time period of each duty cycle;
- stopping the application of conditioned air to the space during said second time period of each duty cycle;
- and
- varying the duration of said first time period in response to changes in the condition sensed in the space.
Dependencies are inferred from the claim text.