US20100095610A1

US20100095610A1 - Venting Apparatus and Methods

Info

Publication number: US20100095610A1
Application number: US12/528,195
Authority: US
Inventors: Nathan S. Hariharan
Original assignee: Carrier Corp
Current assignee: Carrier Corp
Priority date: 2007-02-21
Filing date: 2007-02-21
Publication date: 2010-04-22
Also published as: CN101631993A; HK1140539A1; WO2008103132A1; CN101631993B

Abstract

A building has an interior space, a first wall surface, and a vent. A vortex guide baffle is positioned at least partially separating a vortex chamber from a remainder of the interior space. The vent is along the vortex chamber. The vortex chamber has an inlet opening from the remainder at the wall.

Description

U.S. GOVERNMENT RIGHTS

The invention was made with U.S. Government support under contract 70NANB4H3024 awarded by the National Institute of Standards and Technology. The U.S. Government has certain rights in the invention.

BACKGROUND OF THE INVENTION

The invention relates to building climate control. More particularly, the invention relates to climate control for building spaces subject to wall heating.
Localized wall heating of building spaces may have several causes. Exemplary heating may include solar heating and heating from sources internal to the building. FIG. 1 shows one exemplary solar heating situation in which a building 20 includes a first interior space 22. An exemplary interior space 22 is an atrium having a windowed front wall 24 and (which may also be a ceiling roof) 26. The exemplary atrium has a back wall 28 which may separate the atrium from one or more other interior spaces 30. The atrium may have sidewalls (not shown). The atrium includes a floor 32 which may be at or near a level of the ground 34. The atrium may have an overall height H_Aand the building may have an exemplary overall height H above the ground.
An exemplary solar heating involves light 42 passing through the front wall and/or ceiling to be received by the front surface/face 44 of the back wall 28. The sunlight thus heats the back wall. The heated back wall induces an upward airflow 46 along the back wall. Upon reaching the ceiling 26, the flow passes forward along the roof and then downward along the interior surface/face of the front wall. Upon reaching the floor 32, the airflow 46 may return rearward.
The resulting recirculation of the flow 46 may cause excessive heat to build-up in the space. Addressing this heat build-up may pose loads upon the building's air conditioning system.

SUMMARY OF THE INVENTION

One aspect of the disclosure involves a building having an interior space, a first wall surface, and a vent. A vortex guide baffle is positioned at least partially separating a vortex chamber from a remainder of the interior space. The vent is along the vortex chamber. The vortex chamber has an inlet opening from the remainder at the wall.
In various implementations, the building may have one or more windows positioned to admit sunlight to the interior space to heat the wall to induce an upward airflow along the wall. The vortex guide baffle may be positioned to redirect the upward flow to form a vortex. The vortex may convey the air to exit the vent. The vent may comprise first and second lateral vents proximate first and second ends of the wall. The vortex guide baffle may be positioned to redirect the upward flow to form first and second vortices respectively conveying the air to the first and second lateral vents.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side schematic view of a building interior space with a vortex venting system.

FIG. 2 is an enlarged side schematic view of the venting system.

FIG. 3 is a partial side schematic airflow diagram.

FIG. 4 is a perspective view of the interior space of FIG. 2.

FIG. 5 is a horizontal sectional view of the venting system of FIG. 2.

FIG. 6 is a side schematic view of the system of FIG. 2 in an alternate mode of operation.

Like reference numbers and designations in the various drawings indicate like elements.

DETAILED DESCRIPTION

FIG. 2 shows a ventilation (venting) system 50 positioned along a junction 52 (e.g., corner) between the back wall 28 and the ceiling 26. The system includes one or more vents. FIG. 3 shows an exemplary pair of left and right vents 54A and 54B proximate left and right ends of the back wall at left and right end walls 56A and 56B of the interior space. The vents may pass directly to the building exterior or via duct(s) 60 (FIG. 2). As is discussed in further detail, in at least a first mode of operation, the system may provide a trapped vortex conveying air out the vents. The exemplary system creates twin vortices 62A and 62B (FIG. 4) of the same angular circulation direction and outwardly divergent longitudinal direction (e.g., mirror images about a vertical plane (e.g., a centerplane) 500 between the vents). The vortices 62A and 62B respectively convey air out the left and right vents 54A and 54B.
The exemplary vortices are generated/trapped by a guide baffle 70 (FIG. 2) of the system 50. The exemplary guide baffle 70 cooperates with an upper portion of the back wall and a back portion of the ceiling to define a trapped space (vortex chamber) 72.
The vents 54A and 54B form an exemplary outlet from the trapped space/chamber 72 in the first mode of operation. There is also at least one inlet. The illustrated inlet 74 is a single inlet extending the length of the back wall. The exemplary baffle 70 extends both vertically and horizontally. The exemplary baffle construction has an L-shaped section. An exemplary leg 76 of the L extends generally vertically and an exemplary foot 78 of the L extends generally horizontally. The exemplary inlet is between the end 80 of the baffle foot and the front surface of the back wall.
In the first mode of operation, as the airflow 46 passes up the back wall along the length thereof, the airflow passes through the inlet 74 into the chamber 72. The chamber 72 may have a combination of two effects. First, the confinement associated by the chamber directs the flow laterally toward the outlets. In the exemplary symmetric configuration, this involves an effective lateral split of the flow in mirror images relative to the centerplane 500. Additionally, the momentum of the flow, upon encountering the ceiling (chamber top) is to be turned (i.e., counterclockwise as viewed in FIG. 2). This turning is continued when the flow sequentially encounters the leg 76, the foot 78, and then the back wall 28. FIG. 3 shows an associated cool air recirculation 86 centrally within the atrium and an opposite local circulation 88 near the junction of the front wall and the ceiling.
In certain situations, the warm air recirculation through the interior space 22 may be desirable. For example, in the winter, the heating may advantageously replace or supplement active heating systems. Accordingly, the system may be configured to shift between the first mode wherein the trapped vortex encourages air and heat discharge and a second mode wherein there is either no trapped vortex or the effect of the trapped vortex is, somehow, reduced. In one example, the mode change may be associated with articulation of the baffle 70. The mode change may alternatively or additionally be associated with opening/closing of the vents 54A and 54B. FIG. 6 shows a configuration wherein the leg 76 of the L-sectioned baffle 70 may be articulated to open the vortex chamber and allow the airflow to pass through along its recirculating flowpath. The exemplary articulation is a collapse (e.g., a downward rotation) onto the foot 78. However, other articulations are possible.
The articulation (e.g., of the leg 76) may be manual or driven by an actuator 90 (e.g., an electric motor, pneumatic actuator, hydraulic actuator, or the like). The actuator may be controlled via a control system 100 (FIG. 1) (e.g., which may be integrated into the building's main HVAC control system) responsive to sensor input (e.g., one or more temperature sensors 102A-C at various locations in the interior space). Within the exemplary first mode (vortex venting mode), operation may be essentially passive (discharge of the air through the vents may be unforced). Alternatively, however, the airflow may be supplemented such as by fan forcing via one or more electric fans 104A and 104B which may also be controlled by the control system 100. Exemplary fans 104A and 104B are air handling units (AHUs) of the building's conventional (e.g., existing) HVAC system operated continuously in all venting modes to provide a desired fresh air exchange.
In one example, the mode may be seasonally switched: the vortex venting first mode during the summer; and the second mode during other seasons. Time-of-day may also be used: the vortex venting mode during the significant insolation hours; and the second mode otherwise. As noted above, sensor-dependent operation is also possible.
The first and second modes may be further divided. For example, the second mode may be divided into: one mode with fan-forced non-vortex venting; and another mode with no venting.
In an exemplary implementation, heat removal may be greater in the vortex venting mode than in the fan-forced non-vortex venting mode (e.g., with fan operational parameters being constant, but not necessarily so). The transfer of heat out of the interior space provided by the system may exceed the heat transfer that would be provided by similarly-placed vents (and AHUs) alone even relative to mass flow and even if mass flow were decreased. For example, the AHUs and vents alone, a cooler overall mixture of air may be vented, including greater amounts of airflow drawn: rearward along the ceiling; and from the center of the atrium. The vortex venting mode biases the vented air to be preferentially drawn from the particularly warm upward flow along the back wall. This may allow the vortex venting mode to remove more heat with the same or lesser airflow than the baseline or non-vortex mode.
However, the airflow (e.g., mass flow rate) discharged through the vents may be higher in the vortex venting mode than in the baseline or non-vortex mode. The use of discrete local vents positioned to accept the vortex discharge may also have similar heat transfer and airflow increases over a more evenly distributed vent of similar net cross-section (i.e., a short vent extending the entire lateral length of the back wall).
The venting system may be provided as a retrofit in an existing building or in a reengineering of an existing building configuration. Alternatively, the system may be implemented in a clean sheet design. Exemplary building spaces include tall elevator lobbies/atria of office buildings.
System properties may be optimized via a combination of experimentation and simulation (e.g., computational fluid dynamics). Further complexities of shape, parts, and the like may be added beyond those shown. An exemplary engineering/optimization process may initially dimension various components based upon estimated properties. This may be followed by experimental or simulation refinement. For example, in the basic structure of FIG. 2, the baffle and chamber have a characteristic height H_C. The vents have a characteristic height H_Vboth extending downward from the ceiling. The inlet has a characteristic depth D_I. D_Imay be selected or optimized to be slightly greater than the thermal boundary layer thickness T_Bof the wall at the inlet 74. Exemplary D_Iis 110-115% of the thermal boundary layer thickness. This allows the airflow into the chamber while limiting leakage. An advantageous chamber depth D_Cis substantially greater than D_I(e.g., approximately four times the thermal boundary layer thickness T_B). Exemplary vent height H_Vis approximately one meter for an exemplary atrium height of 150 m. An exemplary chamber height H_Cis moderately greater than the vent height (e.g., approximately 1.4 H_V). Exemplary atrium heights are greater than 20 m, more particularly greater than 50 m.
One or more embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, details of building layout, local climate, and building orientation may influence any particular implementation. Additionally, the degree to which the implementation involves a clean sheet design rather than a retrofit of an existing building may further influence any particular implementation. Accordingly, other embodiments are within the scope of the following claims.

Claims

1. A building (20) comprising:

an interior space (22);

a wall (28) surface (44);

a vent (54A, 54B); and

a vortex guide baffle (70), at least partially separating a vortex chamber (72) from a remainder of the interior space (22), the vent being along the vortex chamber and the vortex chamber having an inlet opening (74) at the wall (28).

2. The building of claim 1 wherein:

one or more windows (24, 26) are positioned to admit sunlight (42) to the interior space (22) to heat the wall (28) to induce an upward airflow (46) along the wall; and

the vortex guide baffle (70) is positioned to redirect the upward flow to form a vortex (62A, 62B), the vortex conveying the air to exit the vent (54A, 54B).

3. The building of claim 1 wherein:

the vortex guide baffle is positioned to redirect an upward flow to form first (62A) and second (62B) vortices of opposite longitudinal direction and common circumferential direction.

4. The building of claim 1 wherein:

the vent comprises first (54A) and second (54B) lateral vents proximate first and second ends of the wall; and

the vortex guide baffle is positioned to redirect an upward flow to form first (62A) and second (62B) vortices respectively conveying the air to exit the first and second lateral vents.

5. The building of claim 1 further comprising:

an actuator (90) coupled to at least a first member (76) of the baffle to shift the first member from a condition associated with a first mode to a condition associated with a second mode:

in the first mode the first member (76) is positioned to redirect a thermal airflow to form a vortex, the vortex conveying the air to exit the vent; and

in the second mode the baffle passing the thermal airflow around the baffle to a ceiling.

6. The building of claim 5 further comprising:

a controller (100) coupled to the actuator to control the actuator and configured to shift the first member from the second condition to the first condition responsive to an excess sensed temperature.

7. A building (20) comprising:

an interior space (22);

a wall (28) subject to heating;

at least one vent (54A, 54B); and

trapped vortex means (50) for directing a flow of air, the flow heated by the wall, to exit the at least one vent in at least a first mode.

8. The building of claim 7 further comprising:

a fan (104A, 104B) positioned downstream of the vent.

9. The building of claim 7 wherein:

the means includes an actuator (90) coupled to at least a first member to shift the first member from a condition associated with the first mode to a condition associated with a second mode, in the second mode the means passing the flow of air to a ceiling.

10. The building of claim 9 further comprising:

a controller coupled to the actuator to control the actuator and configured to shift the first member from the second condition to the first condition responsive to an excess sensed temperature.

11. A method for manufacturing the building of claim 7 comprising retrofitting an existing building to add the vent and the means.

12. A method for climate control of a building interior space comprising:

in at least a first mode:

passing an airflow along a wall of the space to heat the airflow;

passing the airflow through a trapped vortex; and

passing the airflow through a vent to exit the space.

13. The method of claim 12 further comprising:

in at least a second mode:

passing said airflow along a wall of the space to heat the airflow;

passing said airflow across a ceiling; and

passing said airflow down along a second wall.

14. The method of claim 13 further comprising:

shifting from the first mode to the second mode by:

shifting a member from a first condition to a second condition:

in the first condition the member redirecting the airflow to form the trapped vortex; and

in the second condition the member allowing the airflow to proceed to the ceiling.

15. The method of claim 13 further comprising:

shifting from the second mode to the first mode by:

shifting a member from a second condition to a first condition:

16. The method of claim 12 wherein:

the trapped vortex is unforced.

17. The method of claim 12 wherein:

a fan (104A, 104B) positioned downstream of the vent draws the airflow.

18. The method of claim 17 wherein:

there are first and second trapped vortices of essentially the same circulation direction but opposite longitudinal direction.

19. The method of claim 12 wherein:

there are first and second trapped vortices of essentially the same circulation direction but divergently opposite longitudinal direction.

20. The method of claim 12 wherein: