Indoor Air Pressure Management

Abstract

A strategy for minimizing or avoiding the so-called stack effect within buildings (20) includes controlling the temperature within a vertically extending shaft (40) such as an elevator hoistway or stairwell. Controlling the air pressure at each of a plurality of levels (A, B, C, D) within the useable or occupied space of a building (20) allows for controlling a pressure differential between the useable or occupied space and an interior of the shaft (40). Maintaining appropriate pressure differential levels allows for minimizing or avoiding the stack effect that otherwise results in undesirably large drafts between the building interior and the outside, surrounding environment.

Description

FIELD OF THE INVENTION

This invention generally relates to controlling air pressure within buildings. More particularly, this invention relates to controlling air pressure within a building to avoid pressure differentials that result in undesirable airflow between the interior of the building and the outside, surrounding environment.

DESCRIPTION OF THE RELATED ART

There are a variety of situations where airflow management and air pressure

management within a building is desirable and necessary. Various building configurations require controlling airflow between the building interior and the space outside of the building, for example, to prevent undesirably large airflows through passageways (i.e., doorways) that provide access to the building. In some circumstances, the differences in temperature between the inside and outside of the building and the building configuration results in a pressure differential between the inside of the building and the outside environment that results in undesirably large drafts or even gusts between the building interior and the outside, surrounding environment. Such drafts undesirably alter the heat load of the building and may interfere with comfortable passage through a doorway, for example.

One example undesirable airflow through a passageway between a building and an outside area may occur in a high rise building that includes a tall shaft such as an elevator hoistway or a stairwell. Such shafts allow for the so-called stack effect when there are differences between the indoor and outdoor temperatures. The stack effect results in large drafts of air through passageways (i.e., doorways) that provide access to the building when such passageways are open. The difference in pressure between the building interior and the outside environment and the stack effect cause such airflow.

For example, colder air outside of a building during a winter season is heavier than the warm air inside the building. The outside pressure is higher than the inside pressure at lower levels of the building. At upper levels of high rise buildings, the outside pressure is lower than the inside pressure under many circumstances. Accordingly, when there is an opening (such as at a doorway at a lobby entry level of a building) air tends to infiltrate into the building at the lower levels. The air tends to flow toward the top of the building. As airflow tends toward a path of least resistance, the outside air entering the building tends to rise through a vertical shaft such as an elevator hoistway or stairwell toward the top of the building.

One example patent: showing a stack-effect-reducing arrangement is shown in the Japanese Patent Publication No. 07-330247, which was published in December, 1995. Thai document proposes adding cool air to an elevator shaft using suction to draw in outdoor air. That arrangement has limitations.

A typical approach to address undesirable airflow between a building and the surrounding outside environment is to attempt to seal the building from the outside environment Sealing passageways between fee building interior and the outside typically is accomplished using revolving doors. There are various shortcomings and drawbacks associated with that approach. For example, revolving doors tend to limit the number of individuals that can pass through a doorway at any given time. To increase the potential traffic flow, larger revolving doors with larger motors have been introduced. This approach is nu ideal because the larger equipment introduces additional cost and requires additional space.

Another drawback associated with revolving doors is that individuals desiring to pass through an automatically moveable door tend to become anxious about timing their entry into the passageway based upon the motion of the door. In many situations, an individual is not allowed to move slowly or to stop once they enter the vicinity of the revolving door or they may be bumped, by one of the moving door panels.

There is a need for an improved arrangement that minimizes the occurrence of the stack effect to improve airflow management associated with the interior of a building. Additionally, it would be beneficial to be able to eliminate the requirement for revolving doors at building entrances. This invention addresses those needs while avoiding the shortcomings and drawbacks discussed above,

SUMMARY OF THE INVENTION

An exemplary disclosed method of controlling airflow within & building includes controlling airflow through a generally vertical shaft in the building. By maintaining a temperature in the shaft to correspond to an outdoor temperature outside of the building and controlling an air pressure at each level of the building based upon the temperature in the shaft, the disclosed method minimizes the so-called stack effect.

In one example, the air pressures of at least some of the levels of the building are adjusted responsive to a difference between pressure in the shaft and pressure in an occupied building space that is outside of a selected range. One example includes controlling the air pressure at each building level individually. Another example includes grouping sets of building levels into zones and controlling the pressure Within each zone.

A disclosed building includes a plurality of levels. At least one shaft, such as a stairwell or an elevator hoistway, extends generally vertically and provides access to at least some of the plurality of levels within the building. A temperature control mechanism associated with the shaft controls the temperature within the shaft such that the temperature in the shaft corresponds to an outdoor temperature outside of the building.

In one example, the temperature control mechanism includes openings near opposite ends of the shaft to allow airflow between the shaft and the outside of the building.

In one example, a pressure control device controls air pressure on each of the plurality of levels to which the shaft provides access to control a pressure differential between the shaft and an occupied space in the building. By controlling the air pressure on such levels, the pressure differential between the shaft and the floor levels can be controlled in a manner that minimizes the so-called stack effect.

The various features and advantages of this invention will become apparent to those skilled In the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates an example building.

FIG. 2 schematically illustrates selected control components of an example embodiment.

DETAILED DESCRIPTION

FIG. 1 schematically shows a building 20 that includes a plurality of floors or levels A, B, C, D... YY and ZZ. The example building 20 is a high rise building.

At least one vertically extending shaft 40 provides access to at least some of the levels within the budding. In one example, the shaft 40 is an elevator hoistway. In another example, the shaft 40 is a stairwell,

In the illustrated example, a temperature control mechanism is associated with the shaft 40. In this example, the temperature control mechanism comprises openings 42 and 44 that allow for airflow between the interior of the shaft 40 and the environment outside of the building 20, in this example, the openings 42 and 44 are near opposite ends of the shaft to allow a flow passage through the shaft for the outside air to flow through the shaft. Allowing the outside air to flow through the shaft establishes a temperature within the shaft that corresponds to the outside temperature. In some circumstances, the outside temperature and die temperature within the shaft will be approximately equal.

FIG. 2 schematically illustrates selected control components of one example embodiment. In this example, a temperature sensor 50 is supported within the shaft 40 to provide an indication of a temperature within at least a portion of the shaft 40. Depending on the length of the shaft, a plurality of temperature sensors may be spaced along the height of die shaft, A plurality of temperature sensors also allows for accommodating differences in temperature that may occur along the length of the shaft,

A controller 52 receives information from the temperature sensor 50 regarding the temperature within the shaft 40. The controller 52 in one example also receives information regarding an outside temperature outside of the building 20, When the controller 52 determines that there is a difference between the temperature in the shaft and the temperature outside of the building 20 and the difference is outside of a selected range, the controller 52 activates an air mover 54 to increase the amount of outside airflow into the shaft 40. In one example, the air mover 54 comprises a fan.

In one example, the direction of air movement within the shaft 40 Is controlled depending on the outside temperature. On relatively cold days (i.e., the outside temperature is lower than that inside the building) the air is directed through the shaft from the bottom toward the top. This is accomplished using one or more air movers 54 associated with one or more of the openings 42, 44 or otherwise positioned to achieve such airflow through the shaft 40. On relatively warm days (i.e., when the outside temperature is higher than that inside the building) the air is directed from the top toward the bottom of the shaft 40. This is accomplished in one example using at least one air mover 54 to cause the desired direction of airflow through the shaft.

Directing the air movement through the shaft depending on the outside temperature ensures that the outside air in the shaft travels as desired and does not enter the useable or occupied space within the building.

By maintaining a correspondence between the temperature within the shaft 40 and the temperature outside of the building 20, the pressure differential between the shaft and the outside of the building is minimized. This facilitates minimizing die so-called stack effect. Hie disclosed example of FIG. 2 also includes an arrangement for managing pressure at the different levels within the building 20 to minimize a pressure differential between the shaft 40 and the useable or occupied space on each level.

In one example, the temperatures in any stairwell are controlled to correspond to the temperature control in an elevator shaft. This example coordinates temperature management in ail shafts 40 within a building to avoid having pressure increases on stairwell doors, which might otherwise occur if only elevator shaft temperatures were controlled.

Considering the example of FIG. 2, a controller 60 controls the air pressure on an example level YY of the building 20 for even further enhanced airflow control, in this example, the controller 60 controls an air mover 62, such as one associated with a known HVAC system, to increase or decrease the amount of airflow onto the level YY to thereby increase or decrease the air pressure on that level of the building. In the illustrated example, the controller 60 receives information from the temperature sensor 50 regarding the temperature within the shaft 40 to make appropriate air pressure adjustments on the building level. The temperature within the shaft 40 is related to the pressure within the shaft in a generally known .manner. The controller 60 uses such information for maintaining an air pressure in the useable or occupied space of the building level YY to achieve the desired pressure differential between the building level and the shaft 40.

In the example of FIG. 2, a pressure sensor 64 is provided at an appropriate location within the useable or occupied space of the building level YY so that the controller 60 may make appropriate air pressure adjustments to achieve the desired pressure differential between the useable or occupied space and the shaft 40. In one example, some pressure difference will be accommodated. In another example, the controller 60 is programmed to maintain air pressure on the building level such thai there is effectively no pressure difference between the useable or occupied space on that level and the corresponding portion of the shaft 40.

Controlling the air pressure at the building levels to control the pressure differential between the interior of the shaft 40 and the useable or occupied space on each level allows for minimizing the occurrence of the so-called stack effect because there is not a pressure differential that tends to instigate significant airflow into the space within the shaft 40. This allows for not requiring the type of sealing at building entrances that is typically accomplished using revolving doors, for example. By effectively managing the pressure within the building and controlling the temperature and therefore, the pressure, within the shaft 40, the so-called stack effect can be minimized or avoided.

In one example, a controller 60 is assigned to controlling the air pressure on each level within the building on an individual level basis. In another example, groups of building levels are controlled as a single zone. Having each level individually controlled or groups of levels controlled in zones allows for managing different pressure levels at different relative heights within the building to accommodate variations thai occur along the length or height of the shaft 40 and the air pressure differences that occur outside of the building at elevations corresponding to different building levels. Given this description, those skilled in the art will be able to select whether individual level control or zone control Will best meet the needs of their particular situation.

Known relationships between outside air temperature and air pressure and known air pressure control techniques can be employed to achieve air pressures at various levels within a building to achieve a desired pressure differential between a useable or occupied space of a building and a vertically extending shaft. Those skilled in tire art will be able to select from among such known techniques to meet the needs of their particular situation.

The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this invention. The scope of legal protection given to this invention can only be determined by studying the following claims.

Claims

1. An elevator hoistway, comprising:

a shaft through which an elevator cab can move; and

a temperature control mechanism associated with, the shaft to control a temperature within the shaft such that the temperature in the shaft corresponds to an outdoor temperature near the shaft, the temperature control mechanism directing airflow within the shaft in a first direction when the outdoor temperature is lower than, the temperature in the shaft and directing airflow within the shaft in a second, opposite direction when the outdoor temperature is higher than the temperature in the shaft.

2. The elevator hoistway of claim 1, wherein the temperature control mechanism comprises at least one opening near each of opposite ends of the shaft, each of the openings permitting airflow between the shaft and an outdoor environment near the shaft.

3. The elevator hoistway of claim 2, including at least, one temperature sensor that provides an indication of the temperature in at least a portion of the shaft.

4. The elevator hoistway of claim 3, including an sir mover that selectively varies an amount of airflow between the shaft and the outdoor environment responsive to an indication from the temperature sensor that the temperature in the shaft does not correspond to the outdoor temperature within a selected range,

5. The elevator hoistway of claim 2, wherein the openings establish an airflow passage through the shaft for outdoor air to flow through the shaft

6. The elevator hoistway of claim 1, wherein the temperature control mechanism maintains the temperature in the shaft approximately equal to the outdoor temperature.

7. A method of controlling airflow through a generally vertical shaft in a building having a plurality levels, comprising the steps of:

adjusting a temperature in the shaft to correspond to an outdoor temperature outside of the building; and

controlling an air pressure of at least one level of the building based upon the temperature in the shaft.

8. The method of claim 7, including adjusting the air pressure of the at least one level to maintain a pressure difference between the shaft and the level within a selected range.

9. The method of claim 7, including controlling the air pressure of each of the plurality of levels individually.

10. The method of claim 7, including grouping at least two of the plurality of levels in a zone and controlling the air pressure of the zone,

11. The method of claim 7, including controlling the air pressure of each of the plurality of levels to achieve a desired pressure differential between the shaft and each level.

12. The method of claim 7, including increasing an amount of airflow on at least one of the levels to increase the pressure on the at least one level.

13. The method of claim 7, wherein the shaft comprises one of a stairwell, or an elevator hoistway,

14. The method of claim 7, including directing airflow in the shaft in a first direction when the outdoor temperature is lower than the temperature in the shaft and in a second, opposite direction when the outdoor temperature is higher than the temperature in the shaft.

15. The method of claim 7, wherein the building includes a plurality of generally vertical shafts and the method includes coordinating the temperatures within the shafts.

16. A building comprising:

a plurality of levels;

at least one elevator hoistway shaft that provides access to at least some of the plurality of levels;

at least one stairwell shaft that provides access to at least some of the plurality of levels; and

a temperature, control mechanism associated with each of the shafts to control a temperature within each shaft such that the temperatures in the shafts are coordinated and correspond to an outdoor temperature outside of the building,

17. The building of claim 16, comprising a pressure control device that controls an air pressure on each of the at least some of the plurality of levels.

18. The building of claim 17, wherein the pressure control device maintains the air pressure on each level to achieve a desired pressure differential between the air pressure on the level and an air pressure in at least the elevator hoistway shaft

19. The building of claim 16, wherein the temperature control mechanism directs airflow within at least the elevator hoistway shaft in a first direction when the outdoor temperature is lower than the temperature in the elevator hoistway shaft and in a second opposite direction when the outdoor temperature is higher than the temperature hi the elevator hoistway shaft.

20. The building of claim 19, wherein the temperature control mechanism also directs airflow within the stairwell shaft in the first and second directions.