Title:
SYSTEM AND/OR METHOD FOR MONITORING AND/OR CONTROLLING THE RELATIVE INTERNAL AIR PRESSURE OF A FACILITY
Kind Code:
A1


Abstract:
A system is provided for maintaining a balanced interior air pressure in a building (10) having a plurality of different localized areas (20). The system includes: a main fan or set of main fans (12) that is selectively controlled to support a desired overall interior air pressure inside the building (10); a plurality of interior sensors (22), each interior sensor (22) arranged to detect a localized air pressure at one of the areas (20) in the building; a plurality of auxiliary fans (26), each auxiliary fan (26) being provisioned to selectively modify the localized air pressure at one of the areas (20) in the building (10); and, a control unit (11) that is in operative communication with the plurality of sensors (22) to obtain air pressure readings therefrom, in operative communication with the plurality of auxiliary fans (26) to control operation thereof, and in operative communication with the main fan or set of main fans (12) to control operation thereof. Suitably, based upon the localized air pressure detected by a given sensor (22), a corresponding auxiliary fan (26), provisioned for the area in which the air pressure was detected by the given sensor (22), is controlled by the control unit (11) to modify the localized air pressure at the area (20) in the building (10) for which the corresponding auxiliary fan (26) was provisioned.



Inventors:
Goldman, Stuart O. (Scottsdale, AZ, US)
Rauscher, Karl F. (Emmaus, PA, US)
Application Number:
12/207735
Publication Date:
03/11/2010
Filing Date:
09/10/2008
Assignee:
LUCENT TECHNOLOGIES, INC. (Murray Hill, NJ, US)
Primary Class:
International Classes:
F04B49/06
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Foreign References:
JPS6277534A1987-04-09
Primary Examiner:
TOWNS, BRITTANY E
Attorney, Agent or Firm:
FAY SHARPE/NOKIA (Cleveland, OH, US)
Claims:
What is claimed is:

1. In a building having a plurality of different localized areas, a system for maintaining a balanced interior air pressure inside the building, said system comprising: a main fan or set of main fans that is selectively controlled to support a desired overall interior air pressure inside the building; a plurality of interior sensors, each interior sensor arranged to detect a localized air pressure at one of the areas in the building; a plurality of auxiliary fans, each auxiliary fan being provisioned to selectively modify the localized air pressure at one of the areas in the building; and, a control unit, said control unit being in operative communication with the plurality of sensors to obtain air pressure readings therefrom, said control unit being in operative communication with the plurality of auxiliary fans to control operation thereof, and said control unit being in operative communication with the main fan or set of main fans to control operation thereof; wherein, based upon the localized air pressure detected by a given sensor, a corresponding auxiliary fan, provisioned for the area in which the air pressure was detected by the given sensor, is controlled by the control unit to modify the localized air pressure at the area in the building for which the corresponding auxiliary fan was provisioned.

2. The system of claim 1, wherein the corresponding auxiliary fan is turned on by the control unit to boost the localized air pressure at the area in the building for which the corresponding auxiliary fan was provisioned when the localized air pressure detected by the given sensor fails to satisfy a determined threshold.

3. The system of claim 2, wherein the control unit monitors the number of auxiliary fans that are simultaneously turned on, and when that number exceeds a determined amount, then the control unit takes remedial action.

4. The system of claim 3, wherein the remedial action includes increasing an operational speed of the main fan or set of main fans.

5. The system of claim 3, said system further comprising: a warning signal, wherein if the remedial action does not result in the number of auxiliary fans that are simultaneously turned on dropping to or below the determined amount, then the control unit activates the warning signal.

6. The system of claim 2, said system further comprising: an exterior sensor arranged to detect an exterior air pressure at a location outside the building, wherein said control unit is in operative communication with the exterior sensor to obtain air pressure readings therefrom.

7. The system of claim 6, wherein the threshold is determine relative to the exterior air pressure detected by the exterior sensor.

8. The system of claim 7, wherein each of the interior sensors, the exterior sensor, the auxiliary fans and the main fan or set of main fans are in operative communication with the control unit via at least one of a corresponding wireless or hardwired communication link.

9. In a building having a plurality of different localized areas, a method for maintaining a balanced interior air pressure inside the building, said method comprising: (a) selectively controlling a flow of exterior air into the building to support a desired overall interior air pressure inside the building; (b) detecting a localized interior air pressure in each of the localized areas in the building, and, (c) selectively modifying the localized interior air pressure in a given localized area of the building in response to the detected localized interior air pressure at the given localized area varying from the desired overall interior air pressure.

10. The method of claim 9, said method further comprising: provisioning the building with a plurality of auxiliary fans, each auxiliary fan being arranged to affect the localized interior air pressure of one of the localized areas, wherein the step of selectively modifying the localized interior air pressure is achieved by selectively controlling the operation of the auxiliary fan provisioned in the building for the given localized area.

11. The method of claim 10, said method further comprising: monitoring the number of auxiliary fans that are simultaneously turned on; and, when the number exceeds a determined amount, taking a remedial action.

12. The method of claim 11, wherein the remedial action includes increasing the flow of exterior air into the building.

13. The method of claim 12, said method further comprising: outputting a warning signal when the remedial action does not result in the number of auxiliary fans that are simultaneously turned on dropping to or below the determined amount.

14. The method of claim 13, said method further comprising: detecting an exterior air pressure at a location outside the building.

15. The method of claim 14, wherein the desired overall interior air pressure is determine relative to the detected exterior air pressure.

16. The method of claim 15, said method further comprising: provisioning the building with a plurality of interior sensors, each interior sensor detecting the localized interior air pressure at one of the localized areas in the building; and, providing at least one exterior sensor arranged to detect the exterior air pressure.

17. The method of claim 16, said method further comprising: providing at least one of a wireless communication link and a hardwired communication link over which each of the interior sensors, the exterior sensor and the auxiliary fans are in operative communication with a control unit provisioned to control the auxiliary fans based on data received from the sensors.

Description:

FIELD

The present inventive subject matter relates to the art of air pressure monitoring and/or control within a facility. Particular application is found in conjunction with certain types of positively pressurized facilities or buildings, and the specification makes particular reference thereto. However, it is to be appreciated that aspects of the present inventive subject matter are also amenable to other like applications.

BACKGROUND

Commonly, it is desired in some buildings and other facilities to have an internal positive air pressure relative to the outside ambient air pressure. For example, a relative positive internal air pressure is often maintained in facilities where it is desired to keep exterior airborne or other contaminates (e.g., dust, hazardous material, fumes, etc.) from entering the building. For example, relative positive internal air pressure is often employed in hospitals or other medical facilities, computer rooms, telecommunication offices, delicate manufacturing plants, etc. As can be appreciated, the relatively positive internal air pressure generally promotes airflow through openings in the facility or building in an interior to exterior direction, thereby minimizing or otherwise inhibiting airborne or other like contaminates from entering the facility or building through those openings. Typically, a building may employ an HVAC (Heating, Ventilation and Air Conditioning) system to achieve the relative positive internal air pressure. For example, the HVAC system may include an air intake vent and/or fan or the like that draws or otherwise forces exterior air into the building (e.g., through a suitable filter) to achieve the desired positive air pressure within the building relative to the outside air pressure.

While normally a relative positive internal air pressure may be generally maintained in a building or facility, there can be at times localized interior air pressure variations in and/or about the faculty, e.g., caused by localized variations in the outside air pressure, openings in the building, etc. Accordingly, while an overall positive interior air pressure may be maintained in the facility or building relative to the outside air pressure, the relative interior air pressure may tend to become negative (or not sufficiently positive) at some localized points or areas in the facility or building due to the aforementioned causes and/or other reasons. Having such localized points or areas of weak or negative air pressure within a building or facility relative to the exterior air pressure is generally undesirable in many cases, e.g., insomuch as it may facilitate (or in any event not sufficiently hinder) airborne and/or other like contaminants from entering the building at those localized points or areas. While this may not always be a significant problem, it may become so after a wildfire, chemical spill, dirty bomb, or other abnormal event that contaminates the outside air or otherwise significantly degrades the exterior air quality.

Generally, the aforementioned localized variants (i.e., localized areas within the building tending or prone to have a weak or negative internal air pressure relative to the exterior air pressure) are addressed by simply over-engineering the HVAC system or other positive pressure producing system, i.e., so that the overall relative positive internal air pressure generated within the build or facility significantly exceeds the expected demand or what would otherwise be normally desired. However, such a solution has certain limitations and/or drawbacks. For example, the “over-engineering” solution generally wastes energy in the creation of the excess air pressure. Additionally, added cooling and/or heating expenses associated with conditioning the excess air flowing through the facility can also undesirably accompany this solution. Furthermore, the extra air movement itself can be a negative consequence.

Yet another drawback to the over-engineering solution is the potential to actually increase contamination of the interior air. For example, such over-engineering generally means that more outside air must be brought into the facility and that can in turn increase the overall interior contamination since any implemented filtering may not remove 100% of the contaminates. Finally, moving additional air through filters will tend to cause the filters to become clogged more quickly. This can be especially true when the exterior air contamination is significantly high, which is also precisely when a relatively positive interior air pressure is most desirable.

Accordingly, a new and improved internal air pressure monitoring and/or control system and/or method is disclosed that addresses the above-referenced problems and others.

SUMMARY

In accordance with one embodiment, a system is provided for maintaining a balanced interior air pressure in a building having a plurality of different localized areas. The system includes: a main fan or set of main fans that is selectively controlled to support a desired overall interior air pressure inside the building; a plurality of interior sensors, each interior sensor arranged to detect a localized air pressure at one of the areas in the building; a plurality of auxiliary fans, each auxiliary fan being provisioned to selectively modify the localized air pressure at one of the areas in the building; and, a control unit that is in operative communication with the plurality of sensors to obtain air pressure readings therefrom, in operative communication with the plurality of auxiliary fans to control operation thereof, and in operative communication with the main fan or set of main fans to control operation thereof. Suitably, based upon the localized air pressure detected by a given sensor, a corresponding auxiliary fan, provisioned for the area in which the air pressure was detected by the given sensor, is controlled by the control unit to modify the localized air pressure at the area in the building for which the corresponding auxiliary fan was provisioned.

In accordance with another embodiment, a method is provided for maintaining a balanced interior air pressure in a building having a plurality of different localized areas. The method includes: selectively controlling a flow of exterior air into the building to support a desired overall interior air pressure inside the building; detecting a localized interior air pressure in each of the localized areas in the building; and, selectively modifying the localized interior air pressure in a given localized area of the building in response to the detected localized interior air pressure at the given localized area varying from the desired overall interior air pressure.

Numerous advantages and benefits of the inventive subject matter disclosed herein will become apparent to those of ordinary skill in the art upon reading and understanding the present specification.

BRIEF DESCRIPTION OF THE DRAWINGS

The inventive subject matter disclosed herein may take form in various components and arrangements of components, and in various steps and arrangements of steps. The drawings are only for purposes of illustrating preferred embodiments and are not to be construed as limiting. Further, it is to be appreciated that the drawings are not to scale.

FIG. 1 is diagrammatic illustration showing an exemplary internal air pressure control and/or regulation system suitable for practicing aspects of the present inventive subject matter.

FIG. 2 is a flow chart showing an exemplary process or method in accordance with aspects of the present inventive subject matter for balancing internal air pressure within a building and/or correcting localized variations in the internal air pressure.

FIG. 3 is a flow chart showing an exemplary process or method in accordance with aspects of the present inventive subject matter for discriminating generalized changes in the overall interior air pressure from localized variations in the internal air pressure and suitably correcting for the former.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

For clarity and simplicity, the present specification shall refer to structural and/or functional elements, entities and/or facilities, relevant standards, protocols and/or services, and other components that are commonly known in the art without further detailed explanation as to their configuration or operation except to the extent they have been modified or altered in accordance with and/or to accommodate the preferred embodiment(s) presented herein.

With reference now to FIG. 1, there is shown a facility or building 10 including an HVAC system regulated and/or otherwise controlled by an air pressure control unit (APCU) 11 to suitably maintain a balanced air pressure in the building 10 that is generally positive overall relative to an air pressure outside the building 10. As shown, the HVAC system includes a main air intake fan or set of main air intake fans 12 that is selectively operated and/or controlled to draw or otherwise force exterior air obtained via a vent 14 into the building 10, e.g., through a suitable air filter 16. Optionally, the filtered air is in turn delivered via ducts 18 into various rooms or localized areas 20 of the building 10. For simplicity and clarity herein, FIG. 1 shows the building 10 including only two rooms or localized areas 20. However, in practice, the building 10 may optionally include any suitable number of rooms or localized areas (i.e., more or less than two) arranged and/or equipped similarly to the exemplary rooms or areas 20 illustrated in FIG. 1.

Suitably, each room/area 20 is equipped or otherwise provisioned with a sensor 22 that measures or otherwise detects the localized internal air pressure in the room/area 20 where the sensor 22 is located. Suitably, the sensors 22 are wirelessly connected to the APCU 11, e.g., via a radio frequency (RF) or other suitable over-the-air interface. Alternately, the sensors 22 may optionally be hardwired to the APCU 11. In either case, the sensors 22 are arranged to report, send or otherwise communicate localized interior air pressure measurements or other like readings to the APCU 11. Suitably, the sensors 22 may automatically send the measurements or readings periodically, or the sensors 22 may return the reported data, e.g., in response to polling or requests received from the APCU 11, or the data may be intermittently or otherwise communicated from the sensors 22 to the APCU 11 as desired.

Similarly, the outside or exterior ambient air pressure is optionally measured or otherwise detected by one or more corresponding sensors (e.g., such as the illustrated sensors 24) that are located or otherwise arranged about an exterior of the facility or building 10. Suitably, the sensors 24 are wirelessly connected to the APCU 11, e.g., via an RF or other suitable over-the-air interface. Alternately, the sensors 24 may optionally be hardwired to the APCU 11. In either case, the sensors 24 are arranged to report, send or otherwise communicate exterior air pressure measurements or other like readings to the APCU 11. Suitably, the sensors 24 may automatically send the measurements or readings periodically, or the sensors 24 may return the reported data, e.g., in response to polling or requests received from the APCU 11, or the data may be intermittently or otherwise communicated from the sensors 24 to the APCU 11 as desired.

Under normal operating conditions, suitably the main fan or set of main fans 12 is operated and/or controlled by the APCU 11 (e.g., by regulating its speed) to produce and/or maintain a sufficient airflow to generate a generally positive overall air pressure inside the building 10 relative to the air pressure outside the building 10, i.e., the ambient and/or exterior air pressure which is, for example, made known or available to the APCU 11 in accordance with air pressure measurements and/or other like readings obtained by the exterior sensors 24. Optionally, the fan 12 is wirelessly operated and/or controlled by the APCU 11, e.g., via an RF or other suitable over-the-air interface operatively connecting the two for communication therebetween, or alternately, the fan 12 and APCU 11 may be operatively connected to one another via a hardwired communication link. In either event, in accordance with one exemplary embodiment, the APCU 11 optionally controls the operation and/or speed of the fan 12 based upon knowledge of the exterior air pressure obtained from the sensors 24, e.g., so as to produce a desired generally positive overall air pressure inside the building 10 relative to the air pressure outside the building 10. For example, optionally, when a relatively lower exterior air pressure is measured or otherwise detected by the sensors 24, then the APCU 11 sets a relatively lower operational speed for the fan 12, and conversely, when a relatively higher exterior air pressure is measured or otherwise detected by the sensors 24, then the APCU 11 sets a relatively higher operational speed for the fan 12. In this manner, the airflow and/or pressure generated by the selective operation and/or control of the main fan or set of main fans 12 generally results in an overall interior air pressure being produced and/or maintained that is positive by a desired amount relative to the exterior air pressure.

Suitably, the APCU 11 is also programmed or otherwise provisioned to produce and/or maintain a substantially balanced air pressure inside the building 10, i.e., to eliminate or minimize localized variations in the internal air pressure. Optionally, the APCU 11 achieves the aforementioned balancing by selectively operating and/or controlling one or more auxiliary fans (e.g., such as the fans 26 illustrated in FIG. 1) that are located or otherwise arranged within the facility or building 10, e.g., in or adjacent or otherwise near particular rooms or areas 20 of the facility or building 10. Optionally, the fans 26 are wirelessly operated and/or controlled by the APCU 11, e.g., via an RF or other suitable over-the-air interface operatively interconnecting the elements for communication therebetween, or alternately, the fans 26 and APCU 11 may be operatively connected to one another via one or more hardwired communication links.

Regardless of the implemented communication channel, by appropriately operating and/or controlling a particular fan 26 provisioned for or otherwise corresponding to a particular localized area inside the building 10 (e.g., such as a particular room or area 20) that has a weak or negative air pressure (e.g., relative to an air pressure outside the building 10), the APCU 11 can suitably boost or otherwise augment or alter the localized air pressure in the particular localized area to eliminate or minimize the localized variation. For example, in one exemplary embodiment, the APCU 11 compares localized interior air pressure measurements or other like readings obtained from the interior sensors 22 to the air pressure measurement or other like reading obtained from the exterior sensors 24. Optionally, in another alternative embodiment, the APCU 11 simply compares the localized interior air pressure measurements or other like readings obtained from the interior sensors 22 to a set, defined or otherwise determined threshold (e.g., the generally positive overall interior air pressure at which one desires to maintain the building 10). In either case, if the interior air pressure measured or detected in a given localized area where one of the interior sensors 22 is located (e.g., a particular room/area 20) is not sufficiently positive relative to the exterior air pressure measured or detected by the corresponding exterior sensor 24, or as the case may be, if the particular localized interior air pressure does not suitably meet the determined threshold, then the APCU 11 signals or otherwise switches on the particular fan 26 provisioned for or corresponding to that particular localized area (i.e., the particular room/area 20) so as to suitably boost or otherwise augment or alter the localized air pressure in the particular localized area.

Suitably, having turned-on a particular auxiliary fan 26, depending on the magnitude or size of the difference between the localized interior air pressure measured or detected in the given localized area at issue (e.g., the air pressure in the corresponding room/area 20 measured by the corresponding interior sensor 22) and the exterior air pressure (e.g., measured or detected by the corresponding exterior sensor 24), or as the case may be, depending on the magnitude or size of the difference between the localized internal air pressure and the determined threshold, the APCU 11 optionally controls the speed of the turned-on auxiliary fan 26 to produce and/or maintain an airflow therefrom that results in a sufficiently corrective boost, augmentation or other suitable alteration of the localized internal air pressure so as to make the localized internal air pressure positive by a desired amount relative to the exterior air pressure or so as to otherwise make the localized internal air pressure meet the determined threshold. Optionally, once the localized interior air pressure has been restored to a sufficiently positive level relative to the exterior air pressure (e.g., as measured or detected by the respective sensors 22 and 24), or as the case may be, once the localized interior air pressure has meet the threshold, the operational speed of the corresponding auxiliary fan 26 may be maintained by the APCU 11. However, if the localized interior air pressure starts to rise or become overly positive relative to the exterior air pressure or threshold, e.g., due to the operation and/or speed of the corresponding auxiliary fan 26, the APCU 11 may then accordingly reduce the operational speed of the auxiliary fan 26 or even shut-off the fan 26 altogether in order to maintain the localized internal air pressure at the desired level relative to the exterior air pressure and/or threshold. Of course, if the localized internal air pressure again becomes too weak or negative (e.g., relative to the exterior air pressure or threshold), then the APCU 11 optionally turns the corresponding auxiliary fan 26 back on and/or increases its operational speed accordingly in order to maintain the localized internal air pressure at the desired level relative to the exterior air pressure and/or threshold. In this manner, by individually operating and/or controlling separate auxiliary fans 26 located and/or otherwise arranged to provide localized airflow and/or localized air pressure adjustments to different localized areas in the building 10 (e.g., such as the different rooms/areas 20 illustrated in FIG. 1) based upon specific localized interior air pressure measurements and/or readings for the different localized areas in the building 10 (e.g., obtained by the interior air pressure sensors 22), the APCU 11 is able to produce and/or maintain a substantially balanced air pressure inside the building 10 which is sufficiently positive by a desired amount or threshold, e.g., relative to the air pressure outside the building 10 (e.g., measured or detected by the exterior air pressure sensors 24).

Suitably, the APCU 11 continually or otherwise monitors and/or records the states of each auxiliary fan 26 arranged within the facility or building 10, e.g., the operational states of each fan 26 (i.e., on or off), operational speed of each fan 26, etc. In one exemplary embodiment, if the number of auxiliary fans 26 that are turn-on or that are otherwise being operated simultaneously exceeds a set or otherwise determined threshold, then this potentially indicates that the building 10 is experiencing a relatively widespread drop in the overall interior air pressure (e.g., below the level which is generally desired), as opposed to simply an imbalance in the internal air pressure or a localized variation. Accordingly, when this condition is detected by the APCU 11 (e.g., from the monitored state of the auxiliary fans 26), the APCU 11 optionally takes suitable remedial action. For example, to generally raise or otherwise adjust the overall air pressure inside the building 10, the APCU 11 optionally controls the main fan or set of main fans 12 accordingly, e.g., turning-on the main fan or set of main fans 12 and/or increasing its optional speed. As can be appreciated, the foregoing remedial action will generally tend to raise the overall air pressure inside the building 10. Moreover, such an increase in overall air pressure will generally also be detected in the various rooms/areas 20 of the building 10, e.g., by the sensors 22. Accordingly, as described above, the APCU 11 will in turn eventually turn-off one or more of the auxiliary fans 26 when the air pressure in one or more of the rooms/areas 20 reaches or is otherwise restored to the desired level, e.g., as a result of increasing the operational speed of the main fan or set of main fans 12. Accordingly, once the number of auxiliary fans 26 in simultaneous operation drops below the threshold, the APCU 11 may optionally suspend the remedial action previously taken or at least cease further progression of the remedial action—e.g., the operational speed of the main fan or set of main fans 12 may be maintained by the APCU 11 at the level where the number of auxiliary fans 26 in simultaneous operation remains below the threshold.

Notwithstanding implementation of the foregoing remedial action, at times the number of fans 26 in simultaneous operation may not drop below the threshold level as desired. For example, over time the filter 16 may become significantly clogged or otherwise compromised thereby restricting airflow therethrough such that even when the main fan or set of main fans 12 has reached its maximum operational speed there is still not sufficient airflow through the filter 16 to generate or otherwise achieve the desired air pressure inside the building 10, e.g., as measured or otherwise detected by the sensors 22. Accordingly, the APCU 11 is optionally programmed or otherwise provisioned to sound an alarm or provide another visual or audible warning or other suitable indication of this condition. For example, after the APCU 11 has set the operational speed of the main fan or set of main fans 12 to its maximum level or some other desired upper limit, the APCU 11 optionally sets a clock or other timer in motion. Meanwhile, the APCU 11 continues to monitor the operational state of the auxiliary fans 26. If after the expiration of a set or otherwise determined time period (e.g., measured by the aforementioned clock or timer) the number of auxiliary fans 26 in operation has still not fallen below the threshold level, then the remedial action (i.e., increasing the operational speed of the main fan or set of main fans 12) is optionally deemed to have failed, e.g., due to a clogged filter 16. Accordingly, when this condition is met, the APCU 11 optionally generates the aforementioned visual or audible warning or other suitable indication, e.g., which signals maintenance staff or other suitable persons to check, clean, replace or otherwise service the filter 16. Suitably, during the foregoing maintenance, the APCU 11 optionally operates and/or otherwise regulates the auxiliary fans 26 so as to support the relative positive internal air pressure, e.g., while the main fan or set of main fans 12 may be turned off to perform and/or complete the maintenance. In this manner, the auxiliary fans 26 can at least temporarily help prevent or hamper the entry of exterior airborne contaminates or the like (i.e., by supporting the creation of a relatively positive internal air pressure at their respective locations) and give the maintenance staff some time to respond to the alarm condition.

With reference now to FIG. 2, there is shown a process or method 100, e.g., implemented by the APCU 11 to regulate operation of the auxiliary fans 26, that achieves a balanced internal air pressure, e.g., inside the building 10. Suitably, the process or method 100 is implemented for each pair of interior sensor 22 and auxiliary fan 26 arranged in the facility or building 10. Optionally, the entire process or method 100 is iteratively repeated successively and/or continually to maintain a balanced air pressure inside the building 10 over time.

At step 102, the APCU 11 monitors the air pressure (AP) and/or variations or changes therein over time. Suitably, the internal air pressure of a localized region within the building 10 is monitored, e.g., such as in a room or area 20, and optionally, the corresponding exterior air pressure is also monitored. In one suitable embodiment, air pressure measurements or other like readings are periodically, intermittently or otherwise obtained by the APCU 11 from the interior sensor 22 and/or optionally from a corresponding exterior sensor (e.g., such as exterior sensor 24).

At decision step 104, the APCU 11 compares the localized interior air pressure (LIAP) to a set or otherwise determined threshold (THLIAP). Suitably, THLIAP is set or otherwise determined to reflect the desired interior air pressure, e.g., which is optionally some positive amount relative the monitored exterior air pressure, some absolute value, or otherwise. In the illustrated example, if the LIAP is less than the threshold THLIAP, e.g., by more than a given tolerance, then the process 100 branches to step 120. Alternately, if the LIAP exceeds the threshold THLIAP, e.g., by more than a given tolerance, then the process branches to step 140. Otherwise, if the LIAP is substantially equal to the threshold THLIAP, e.g., within a given tolerance, then the LIAP is acceptable and the current iterative cycle of the process 100 may end, while optionally maintaining the current operational state of the auxiliary fan 26.

At step 120, the APCU 11 sets the operational state of the auxiliary fan (AF) 26 to “on” and optionally provides the AF 26 a suitable signal or other message indicating the same. At decision step 122, the monitored LIAP is again compared to the threshold THLIAP. If the LIAP remains less than the threshold THLIAP, e.g., by more than a given tolerance, then the process 100 continues to step 124, otherwise if the monitored LIAP now meets or exceeds the threshold THLIAP, e.g., by more than a given tolerance, then the LIAP has been sufficiently corrected and the current iterative cycle of the process 100 may end, while optionally maintaining the current operational state of the AF 26.

At decision step 124, the APCU 11 checks the speed of the AF 26, e.g., known from the monitored operational state of the AF 26. If the speed of the AF 26 is already at its maximum or at or above some other upper limit, then the process 100 continues to step 126 where the APCU 11 provides an audible or visual or other suitable warning or other like indication of the current fault condition—namely, that the desired LIAP cannot be reached or maintained even at the maximum or upper limit of the AF's operational speed. Optionally, the APCU 11 may also take further automatic remedial actions, e.g., such as increasing the speed of the main fan or set of main fans 12. In any event, following step 126, the current iterative cycle of the process 100 may suitably end, while optionally maintaining the current operational state of the AF 26. Alternately, at decision step 124, if the speed of the AF 26 is not at its maximum or is below some other upper limit, then the process 100 branches to step 128 where the APCU 11 incrementally or otherwise increases the operational speed of the AF 26 and the process 100 loops back and/or otherwise returns to step 122.

At decision step 140, the APCU 11 checks the operational state of the AF 26. If the AF 26 is off, then the process 100 continues to step 142 where the APCU 11 provides an audible or visual or other suitable warning or other like indication of the current fault condition—namely, that excessive LIAP is being experienced even when the AF 26 is off. Optionally, the APCU 11 may also take further automatic remedial actions, e.g., such as decreasing the speed of the main fan or set of main fans 12. In any event, following step 142, the current iterative cycle of the process 100 may suitably end, while optionally maintaining the current operational state of the AF 26. Alternately, at decision step 140, if the AF 26 is on, then the process 100 branches to step 144, where the APCU 11 checks the speed of the AF 26, e.g., known from the monitored operational state of the AF 26.

At decision step 144, if the speed of the AF 26 is already at its minimum or at or below some other lower limit, then the process 100 branches to step 146 where the APCU 11 sets the operational state of the auxiliary fan (AF) 26 to off and optionally provides the AF 26 a suitable signal or other message indicating the same. As shown, following step 146, the process 100 jumps to step 150 (i.e., bypassing step 148). Alternately, at decision step 144, if the speed of the AF 26 is above its minimum or some other lower limit, then the process 100 continues to step 148 where the APCU 11 incrementally or otherwise decreases the operational speed of the AF 26 and the process 100 then continues to step 150.

At decision step 150, the monitored LIAP is again compared to the threshold THLIAP. If the monitored LIAP remains above the threshold THLIAP, e.g., by more than a given tolerance, then the process 100 returns to step 140, otherwise if the monitored LIAP now meets or has dropped below the threshold THLIAP, e.g., by more than a given tolerance, then the LIAP has been sufficiently corrected and the current iterative cycle of the process 100 may end, while optionally maintaining the current operational state of the AF 26.

With reference now to FIG. 3, there is shown a process or method 200, e.g., implemented by the APCU 11, to discriminate between generalized drops, losses or other changes in overall air pressure inside a facility such as the building 10 and localized variations or imbalances experienced in the internal air pressure. Optionally, the entire process or method 200 is iteratively repeated successively and/or continually to guard against generalized losses or other unwanted changes in overall internal air pressure, while still maintaining a balanced air pressure inside the building 10 over time. Suitably, iterative cycles of the process or method 200 may optionally be executed concurrently and/or consecutively with each iterative execution cycle of the above-described process or method 100.

At step 202, the APCU 11 monitors and/or records the current operational state of each of the AFs 26 arranged in the facility or building 10. For example, the APCU 11 monitors and/or records which AFs 26 are on and/or off, the set or operational speed of each AF 26, etc.

At decision step 204, the number (N) of AFs 26 that are currently operating (i.e., in the “on” state) is compared to a set or otherwise determined threshold (TH). As shown in the illustrated embodiment, if N is not greater than or otherwise does not meet the threshold TH, then a generalized drop or decrease in overall interior air pressure is deemed as not being experienced, and the current iterative cycle of the process 200 may end, while optionally maintaining the current operational state of the main fan (MF) or set of main fans 12. Otherwise, if N is greater than or does otherwise meet the threshold TH, then a generalized drop or decrease in overall interior air pressure is deemed as being experienced, and the process 200 accordingly continues on to step 206 for suitable remedial action.

At step 206, the operational state of the MF 12 is determined, e.g., by the APCU 11. If the MF 12 is already on, then the process may advance directly to step 210, otherwise if the MF 12 is off, the process branches to step 208 where the APCU 11 turns on the MF 12 before proceeding to step 210. At step 210, the operational speed of the MF 12 is compared (e.g., by the APCU 11) to its maximum or other upper limit. If the maximum speed or other upper speed limit of the MF 12 has not been reached or met, then the process 200 advances to step 212 where the operation speed of the MF 12 is incrementally or otherwise increased (e.g., by the APCU 11) and then the process 200 loops back and/or otherwise returns to step 204.

Alternately, at step 210, if the MF 12 has already reached or otherwise met its maximum speed or other upper speed limit, then the process 200 branches to step 214 where it is determined whether or not a timer or clock has been started or is currently running. Suitably, the timer or clock is programmed or otherwise provisioned (e.g., within the APCU 11) to count-down or otherwise measure or mark a set or otherwise determined time period. If the timer/clock has not been started or is not yet running, then the process 200 branches to step 216 where the timer/clock is started and the process then loops back and/or otherwise returns to step 204. Otherwise, if the timer/clock has already been started, then the process 200 advances to step 218.

At decision step 218, the APCU 11 checks the timer/clock to determine if the set or otherwise determined time period has expired. If the set or otherwise determined time period has not expired, then the process 200 loops back and/or otherwise returns to step 204, otherwise, if the set or otherwise determined time period has expired, then the filter 16 is deemed to be clogged or otherwise compromised insomuch as the airflow produced by the MF 12 operating at its upper or maximum speed limit for the designated time period has still failed to produce the desired effect, i.e., a generalized increase in overall interior air pressure sufficient to decrease the number (N) of AFs 26 simultaneously being operated to a level below the determined threshold TH, and accordingly, the process 200 continues to step 220. At step 220, the APCU 11 provides an audible or visual or other suitable warning or other like indication of the current fault condition. Optionally, the APCU 11 may also take further automatic remedial actions, e.g., such as operating or regulating one or more of the AFs 26 so as to support the relative positive internal air pressure, e.g., while the main fan or set of main fans 12 may be turned off to perform and/or complete maintenance on the filter 16.

In one optional embodiment, the foregoing internal air pressure control system is intended to be retrofit into an existing building. Accordingly, employing portable floor fans 26 and/or wireless communication links between the APCU 11 and the sensors 22 and 24 and between the APCU 11 and the auxiliary fans 26 facilitates quick and easy installation of the system. However, in alternate embodiments, the system may be installed in conjunction with new construction or renovation of a building or facility, in which case it may be more suitable and/or desirable to employ hardwired communication links between the various elements and/or more permanently installed auxiliary fans 26. Additionally, while the foregoing description has been made with reference to producing and/or maintaining a generally positive internal air pressure relative to the external air pressure, those of ordinary skill in the art will appreciate that the foregoing description and/or above-described internal air pressure control system can be readily adapted to maintain a relatively negative internal air pressure if it should so be desired.

In any event, it is to be appreciated that in connection with the particular exemplary embodiments presented herein certain structural and/or function features are described as being incorporated in defined elements and/or components. However, it is contemplated that these features may, to the same or similar benefit, also likewise be incorporated in other elements and/or components where appropriate. It is also to be appreciated that different aspects of the exemplary embodiments may be selectively employed as appropriate to achieve other alternate embodiments suited for desired applications, the other alternate embodiments thereby realizing the respective advantages of the aspects incorporated therein.

It is also to be appreciated that particular elements or components described herein may have their functionality suitably implemented via hardware, software, firmware or a combination thereof. Additionally, it is to be appreciated that certain elements described herein as incorporated together may under suitable circumstances be stand-alone elements or otherwise divided. Similarly, a plurality of particular functions described as being carried out by one particular element may be carried out by a plurality of distinct elements acting independently to carry out individual functions, or certain individual functions may be split-up and carried out by a plurality of distinct elements acting in concert. Alternately, some elements or components otherwise described and/or shown herein as distinct from one another may be physically or functionally combined where appropriate.

In short, the present specification has been set forth with reference to preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the present specification. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.