The invention relates generally to integrated air flow devices for use with lightly pressurized air streams found in buildings utilizing raised access floor HVAC, ducts or plenums.
Many prior art devices and methods have been devised for heating and air conditioning HVAC systems in buildings. Variable air volume (VAV) is well known terminology in the HVAC industry and applies to systems and devices (often called terminals) that change the flow/volume of cool conditioned air to achieve a balance with, the amount of heat gained in the space or building and thereby maintain suitable temperature control of the occupied space. Many such supply air terminals have commercial market application for both ducted systems and in pressurized access floor air plenum HVAC systems.
Fin tube heating where hot/heating water runs through a copper or steel tube or pipe with perpendicular aluminium fins is one of the most common methods of applying heat at building exterior walls and under windows. Heating coils are the most common method of heating air streams in air ductwork and large building supply fans. There arc also electric coils used in similar air stream manner as well as electric finned heating devices used in electric base board heating.
Some HVAC systems have been devised for raised access floor systems. Raised access floor systems generally comprise a series of spaced apart pedestals which are supported on the lower end there of on a concrete building structural floor while the upper end there of supports a series of panels defining a raised floor. The space between the said raised floor and the concrete floor defines a cavity or floor plenum. For example, U.S. Pat. No. 4,775,001 relates to the design of air terminal devices used in raised floor air supply plenum systems while the U.S. Pat. No. 6,209,330 relates to an air handler based on chilled water as the cooling force that pushes cool/conditioned air into the raised floor under pressure for cooling computer rooms.
Under floor air distribution systems using the floor plenum of the raised access floor as a supply air pathway is a proven technology and growing significantly in the North American market place. The most current versions of the raised access floor utilize in floor air terminals which sit on the surface of a floor tile and have the body of the terminal extend into the floor plenum or cavity through a hole in said floor tile or panel. The body of the terminal has openings and a grille for air dispersion. The openings in the terminal are exposed to the floor plenum air. These terminals have various forms or mechanisms for opening and closing the in floor openings. This is typically done both manually by the occupant directly or by electric /electronic actuators controlled by a building control system typical of today's building technology.
These raised floor air terminals are generally pressure dependent and deliver predictable range of air flow based on stable floor cavity air pressure whereby the volume of air to the occupied space above the raised floor is a function of the amount and size of openings exposed to the floor pressure and the resistance of the air dispersion grille on the surface of the tile. This in floor plenum pressure is maintained as a constant by in floor pressure sensors providing information to a building control system to control the speed of the fan delivering the air to the plenum all in a manner well known to persons skilled in the art.
The fan flow generally is adjusted via the control system to maintain a pressure setting between 0.03 inches water gauge to 0.10 inches water gauge.
The supply air delivered to the air plenums is also typically cooled/conditioned by chilled water cooling coils in said fans, controlled by the building control system and may generally operate at set points from 53° C. to 70° F. with 64° F. being a typical set point.
Given a floor cavity or plenum with conditioned air at pressure so mentioned the building is cooled by the amount of air, cooler than the occupied space temperature condition, permitted to go through the air terminal into the occupied space. A plurality of terminals is used for rooms and occupied floor in buildings.
At the exterior walls of a building it is well known to those appropriately trained and skilled that heat is lost from and gained to the building occupied volume. It is for this reason and particularly in raised access floor HVAC buildings, air terminals are located adjacent to the exterior walls and are operated in conjunction with, or have their own integral, heating devices so that these exterior wall (commonly referred to as perimeter walls) air terminals can compensate for both heat gain and heat loss.
Various in-floor terminals in the North American market place work with separate traditional convective heating fin tube systems typically under the windows. Several current and recent market offerings provide integral fin tube heating and with automatic cooling ability using a well known rotating damper blades on an axis to control the cooling pathways in the terminal. These units also utilize one chamber cooling air flow and a separate chamber for the heating fin tube.
It is an aspect of this invention to control the flow of air, as typically conditioned for HVAC application, from a lightly pressurized plenum, as typically found in raised floor/under floor air HVAC systems (or also duct plenums) into and through the invention (hereafter called an air flow control terminal or simply air terminal). Said air terminal is typically mounted with top surface level with or on top of said raised floor with the majority of the body of the terminal below the raised floor and surrounded by the pressurized conditioned air in the floor cavity or floor plenum. It is another aspect of this invention that the control of air flow from the lightly pressurized plenum or floor cavity will be done by a sliding damper or air control valve assembly which operates by sliding parallel planes of rigid material (typically sheet metal) each with holes through which air may flow, herein called a plate or blade damper. It is a further aspect of this invention that air permitted to flow from the lightly pressurized conditioned air plenum of the raised floor cavity through the damper will enter the body or single chamber of the air terminal. It is yet another aspect of this invention that this single chamber will contain heating means and it is the integration of the heating means and blade damper in a single chamber of the terminal that allows the terminal to be more space efficient than prior art. It is an additional aspect of this invention that air flowing through the damper, into the chamber, through the heating means will leave the terminal by supply air grille at the top of the terminal which directs air into the occupied space above the raised floor with grille air pattern capability as known and applied by those skilled in the art.
Therefore, in accordance with one aspect of the invention, there is provided an airflow control terminal for use in controlling the supply of air into a building interior. The airflow control terminal includes a rectangular housing having a bottom, a top, two opposite sides and an interior, said top including a grill for allowing air to flow from the interior of the housing to the interior of the building. A heating unit is positioned in the interior of the rectangular housing above the bottom and below the top. One of said bottom and opposite sides has a plurality of first apertures dimensioned to permit air to flow from outside the housing into the interior of the housing. A damper is slidingly mounted to the said bottom and opposite sides having the first apertures, the damper having a plurality of second apertures dimensioned and positioned on the damper such that the damper can slide between a first position wherein the first and second apertures are aligned to permit an airflow from outside of the rectangular housing to the interior of the rectangular housing and a second position wherein the first and second apertures are misaligned and the airflow is obstructed. The heating unit is positioned above the first and second apertures.
In accordance with another aspect of the present invention, there is provided an airflow control terminal as described in the preceding paragraph wherein the airflow control terminal is coupled to a lightly pressurized conditioned air passage such that the airflow is from the lightly pressurized conditioned air passage into the interior of the housing.
In accordance with another aspect of the present invention, there is provided an airflow control terminal as described in the preceding paragraph wherein the airflow through the control terminal has a volume rate which is a function of a degree of alignment between the first and second apertures and wherein the first and second apertures are dimensioned and configured such that there is a linear relationship between the volume rate of airflow and the movement of the damper between its first and second positions. The movement of the damper can be any incremental position in between the first and second position.
In accordance with another aspect of the present invention, there is provided an airflow control terminal as described in the previous paragraphs wherein the airflow control terminal is able to function in a cooling mode by shutting off the heating means, the amount of cooling in the building interior being controlled by the amount of airflow through the airflow control terminal.
In accordance with yet another aspect of the present invention, there is provided an airflow control terminal as described in the previous paragraphs wherein the airflow control terminal is able to operate in two heating modes, a first heating mode wherein the damper is positioned close to its second position to minimize the airflow into the interior of the housing to enhance convection through the heating means and a second heating mode wherein the damper is positioned close to its first position to maximize the airflow into the interior of the housing when the lightly pressurized conditioned air passage has an ambient air pressure.
With the foregoing in view, and other advantages as will become apparent to those skilled in the art to which this invention relates as this specification proceeds, the invention is herein described by reference to the accompanying drawings forming a part hereof, which includes a description of the preferred typical embodiment of the principles of the present invention.
a is a top plan view of the air damper/valve portion of the present invention in its fully closed orientation.
b is a cross sectional view through
a is a top plan view of the air damper/valve portion of the present invention in its fully opened orientation.
b is a cross sectional view through
a is a plan view of the air damper/valve portion of the present invention in it's partially opened orientation.
b is a cross sectional view through
In the description that follows like parts are marked throughout the specification and the drawings with the same reference numerals. The drawings are not necessarily to scale and in some instances proportions may have been exaggerated in order to more clearly depict certain features of the invention.
Referring firstly to figures la through 3b, the valve portion of the present invention is shown generally as item 10 generally consists of two flat pieces of rigid material, typically sheet metal, and for the purposes of this description called damper plates or blades. These damper plates 1a and 1b will each have holes 22 and 24, respectively. The damper plates will typically be oriented with one plate or blade laid with planes of the plates next to each other, one atop the other or potentially side by side. The damper plates are slidingly attached to each other such that one plate may slide relative to the other from a first position, as shown in
The damper plate holes 22 and 24 will typically be similar or identical size and shape on each damper plate; however, different shapes, sizes and orientations may be used to achieve differences in flow for a given amount of slide of the damper plates relative to each other.
The slide damper/air valve may work with each plate sliding but more typically one plate would be a sliding damper and the other would he fixed and be formed into the housing of the air terminal as seen in
Referring now to
In the case of the typical application as seen in
The normal operating method for this airflow and heating control supply air terminal would be to operate in a cooling mode and a heating mode. These modes would typically be controlled by electric/electronic controls devices normally found in the building HVAC industry and as applied by those skilled in the art. In order to satis1˜′ the room or space temperature as measured by a temperature sensor or thermostat the control system engages heating or cooling as necessary.
In cooling mode the method is to control the amount of cool pressurized air released from the floor plenum through the terminal and air grille and releasing the conditioned air to the occupied space. In this invention this is done by sliding the damper blade to align the holes to a greater degree when more cooling is required. The building automation system energizes the terminal actuation for the blade damper in a modulating fashion to match cooling air flow with, heat gain in the space through windows or internal gains (people, lights, equipment). In heating mode the heating means, in this example means fin tube 40 (an industry standard device) operates by building heating water circulating through the tube. The tube and fins normally convect heat to the surrounding space.
With reference to
Another mode for heating is also available when building air conditioning systems that normally provide the conditioned pressurized air supply to the plenum 12 are shut off in night mode or weekend mode.
Under this condition the sliding plate damper 1 moves to the 100% open position (holes frilly aligned) and the fin tube heating operates in pure convection mode (without pressurized airflow assistance) with a convection air stream and path from the floor plenum 12 through the holes 42 and 44 (see
It is also possible to create a cooling only terminal based on this rectilinear configuration which may be applied where heating is provided by other methods at other locations or not required due to climate or placement of terminal where there are no heat losses but only heat gains. In
It is further possible to configure the damper to shape differently and use multiple surfaces of the terminal. In
A specific embodiment of the present invention has been disclosed; however, several variations of the disclosed embodiment could be envisioned as within the scope of this invention. It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.
This application claims priority from U.S. provisional patent application No. 61/390,206 filed on Oct. 6, 2010 the entirety of which is incorporated herein by reference.
Number | Date | Country | |
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61390206 | Oct 2010 | US |