AIR MOVEMENT SYSTEM

Abstract

An air movement system (10) is provided which comprises at least one fan (40), a plurality of exhaust (70) and/or supply points connected to the at least one fan by ducting (50), a plurality of dampers (80) each associated with at least one exhaust and/or supply point for regulating air flow through it, a plurality of sensors (90) each associated with at least one exhaust and/or supply point for sensing a predefined activity within a predefined locale of the at least one exhaust and/or supply point, and a programmable controller (120). The controller is connected to the fan, the dampers and the sensors, and is configured to automatically adjust a damper associated with an exhaust and/or supply point, and adjust the at least one fan, in response to a signal generated by a sensor associated with the same exhaust and/or supply point.

Description

The present invention relates generally to an air movement system and a method of operating an air movement system and finds particular, although not exclusive, utility in an air extraction system.

Air movement systems comprising a fan drawing air out of exhaust points or blowing air in through supply points are well known. It is also known to include dampers, or valves, to control or regulate the flow of air through the ducting associated with such systems. These dampers can be used to isolate areas of a building from direct air movement. Moreover, the fans can be regulated to control their speed and thus the volume flow rate of air through them. The controls for such systems tend to be individual manually controlled switches.

The air movement systems may be forced supply systems, extract systems or may comprise a combination of exhaust and supply such as found in large buildings, for example hotels.

However, with increased attention being paid to the efficiency of all electrical systems, for both economic and environmental considerations, it is desirable to have a better controlled air movement system so that all manner of system criteria may be monitored and regulated to improve efficiency thereof.

In a first aspect the invention provides an air movement system programmable controller for operating an air movement system, the air movement system comprising: at least one fan; a plurality of exhaust and/or supply points connected to the at least one fan by ducting; a plurality of dampers, each damper associated with one of the at least one exhaust and/or supply points, each damper for regulating air flow through the respective associated exhaust and/or supply point; and a plurality of sensors, each sensor associated with either: one of the at least one exhaust and/or supply points for sensing a predefined activity within a predefined locale of the at least one exhaust and/or supply points; or a predefined point in the ducting; wherein the programmable controller is connectable to the fan, the dampers and the sensors, and is configured to: automatically adjust the damper associated with one of the at least one exhaust and/or supply points; and adjust the at least one fan; in response to a signal generated by the sensor associated with the same one of the at least one exhaust and/or supply points.

In a second aspect, the invention provides an air movement system comprising at least one fan; a plurality of exhaust and/or supply points connected to the at least one fan by ducting; a plurality of dampers, each damper associated with one of the at least one exhaust and/or supply points, each damper for regulating air flow through the respective associated exhaust and/or supply point; a plurality of sensors, each sensor associated with either: one of the at least one exhaust and/or supply points for sensing a predefined activity within a predefined locale of the at least one exhaust and/or supply points; a predefined point in the ducting; and a programmable controller, wherein the controller is connected to the fan, the dampers and the sensors, and is configured to: automatically adjust the damper associated with one of the at least one exhaust and/or supply points; and adjust the at least one fan; in response to a signal generated by the sensor associated with the same one of the at least one exhaust and/or supply points.

The programmable controller may be configured to: determine if the at least one fan is fixed-speed or variable-speed; determine which dampers are open; receive a signal generated by the plurality of sensors, the signal indicative of a sensed predefined activity; in response to a determination that the at least one fan is a fixed-speed fan, operate the at least one fan in accordance with a pre-set rule, the pre-set rule selected from a plurality of pre-set rules in response to a determination as to which dampers are open, and in response to a reception of the signal indicative of the sensed predefined activity; and in response to a determination that the at least one fan is a variable-speed fan, operate the at least one fan such that the speed of the at least one fan is set to be approximately proportional to the ratio of the total cross-sectional area of all of the plurality of dampers that are open to the cross-sectional area of a predefined duct.

The sensors may be any one or more of a PIR, a pressure sensor, a temperature sensor, a current sensor or any other manner of 24-volt switch. Any one of the preceding list may be excluded from being provided.

In this way, a PIR in a hotel bedroom may detect the presence or absence of occupants and inform the controller of this fact. The controller may then operate the system to supply fresh air to the bedroom when occupied and cease supplying it when not occupied. Since in hotels such air movement systems are relatively large and complex several fans, both exhaust and supply, may be provided. Furthermore relatively long lengths of ducting, with main ducts and branch ducts, are provided throughout the building.

The controller may be programmed to operate the system in as an efficient manner as possible. For instance, the controller may vary fan speeds, and open and close dampers to regulate air flow throughout the various ducts to ensure that air is only supplied and extracted where and when necessary.

The system may be pre-programmed to keep open predetermined dampers and a fan running at a predetermined speed when the system is in a ‘stand-by’ state, where no activity is occurring within the building.

The controller may be connected wirelessly and/or by wire to the fan, the dampers and the sensors. A combination of wireless and wired connections is contemplated.

The controller may be configured to automatically adjust at least one damper and the at least one fan to maintain a minimum or maximum airflow through the air movement system at predetermined times of day and for a predetermined period of time regardless of sensed activity or inactivity.

For instance, using the hotel example, the system may be set to supply fresh air into every bedroom at a maximum volume flow rate (or at least, at a rate greater than typical), and exhaust air from every bathroom at a maximum volume flow rate (or at least, at a rate greater than typical), for thirty minutes at 12:00 hours every day when the hotel rooms are typically unoccupied. Individual room overrides to prevent such air exchange may be provided as required, for instance by the use of a PIR to detect occupancy, or by a receptionist informing the system not to disturb that room until further notice.

The minimum airflow situation may be exemplified in a situation such as a factory where dust is created during working hours and it is undesirable to switch off the system immediately after the last person has left. Rather, the system may be operated for a further predetermined fifteen minutes to ensure no settling of dust within the system.

The system may include a first power supply, and any one or more of the dampers, fan, sensors and controller may include a second power supply for adjusting the at least one fan and the plurality of dampers when the first power supply is unavailable. The second power supply may be a battery back-up supply.

In this way, graceful shut-down of the system may be effected if the first power supply fails so as to prevent exhaust or supply points being left open or closed.

The controller may include an override setting such that each damper and the fan are controllable individually and distinct from any pre-programming. This allows for unusual situations such as chemical spills leading to noxious fumes in industrial settings.

The controller may include a pre-determinable time period after which the override setting will be cancelled returning the controller to run in accordance with its pre-programming. This prevents the system being left with the fans running at maximum unnecessarily after the incident has been attended to.

However, the controller may be configured to prevent the fan being operated at a predetermined volume-flow rate when a predetermined number of dampers are in the closed position. For instance, the controller may be pre-programmed to prevent the fan being run at maximum volume flow-rate with all the dampers in the closed position as this might collapse the ducts, or at the very least, cause them damage. Other scenarios may also be pre-programmed to prevent damage to the system as appropriate. For instance, the controller could be pre-programmed to ensure that a minimum number of dampers must be open before the fan is increased in speed beyond a predetermined threshold value.

The controller may be configured to connect to a graphical user interface, or the system may include a graphical user interface, and any one or more of the fan, dampers, sensors and exhaust/supply points may be indicated graphically on the interface, and the controller may be programmable by means of visually associating on the interface any one or more of the fan, dampers, sensors and exhaust/supply points with any of the others.

The graphical user interface may be a screen or monitor. It may be incorporated into the controller or may be connected thereto. Also, the screen may be part of a computer to which the controller is connected.

Each element of the system may be represented by an icon on the screen. A ‘drag and drop’ approach may be used to connect or associate the various elements to one another. Other ways of associating them is also contemplated such as by drawing lines between the various elements with a mouse.

Characteristics of the various elements may be entered using the graphical user interface, such as the fan diameter, minimum and maximum speed, duct sizes and lengths, the type of locale by each exhaust and supply point and so on.

The graphical user interface may be configured to provide graphical illustrations of predetermined criteria relating to the system over time. For instance, the predetermined criteria may be one or more of power consumption, volume flow-rates and cost. This information may be obtained by processing data stored in a memory, and therefore the system may include a memory for storing system events over time.

The controller may be configured to be connectable to a computer over a communications network. For instance, a LAN, WAN or other such system. In this way and with appropriate permissions the system may be pre-programmed and interrogated remotely.

The controller may be configured to be accessible via a web browser.

The air movement system may include a filter for filtering air as it passes into or out of the system. The filter may be connected to the controller. This may allow the controller to monitor the filter's performance and/or state of efficiency such that a signal may be generated when maintenance is required.

In a third aspect the invention provides a method of operating an air movement system comprising the steps of providing an air movement system according to the second aspect, and operating the programmable controller to automatically adjust the damper associated with one of the at least one exhaust and/or supply points, and adjust the at least one fan, in response to a signal generated by the sensor associated with the same one of the at least one exhaust and/or supply points.

In a fourth aspect, the invention provides a method of operating an air movement system comprising the steps of providing an air movement system according to the second aspect, determining if the fan is fixed-speed or variable-speed, determining which dampers are open, providing a pressure sensor at a pre-defined point in the ducting and determining the air pressure, and using the controller to operate the fan in accordance with pre-set rules dependent on the determination as to whether or not the fan is fixed-speed or variable speed, on the determination as to which dampers are open, and on the determination of measured air pressure at the pre-defined point, wherein one pre-set rule operates the fan if it is a variable-speed fan such that the speed is set to be approximately proportional to the ratio of the total cross-sectional area of each damper which is open to the cross-sectional area of a pre-defined duct.

If the ratio is less than a predefined threshold value the fan may be operated at a pre-set speed. For instance, a minimum speed may be set.

The pre-defined duct may be the main intake and/or exhaust duct.

The system may include a filter and the method may further comprise the steps of determining if the fan is operational and operating the fan in accordance with said determination. For instance, if the fan is running then the filter may be activated. Alternatively, if the fan is not running the filter may be deactivated.

The system may be sub-divided into groups of devices and any of the method steps may be repeated for each group to ensure granular control of the overall system.

Throughout this specification the term ‘air movement system’ has been used, however, it will be understood that in one embodiment, the term ‘ventilation system’ may be used alternatively or additionally.

The above and other characteristics, features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. This description is given for the sake of example only, without limiting the scope of the invention. The reference figures quoted below refer to the attached drawings.

FIG. 1 is a schematic plan of an air movement system according to one embodiment of the invention; and

FIG. 2 is a schematic plan of an air movement system according to another one embodiment of the invention.

The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn to scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other orientations than described or illustrated herein.

It is to be noticed that the term ‘comprising’, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression ‘a device comprising means A and B’ should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

Similarly, it is to be noticed that the term ‘connected’, used in the description, should not be interpreted as being restricted to direct connections only. Thus, the scope of the expression ‘a device A connected to a device B’ should not be limited to devices or systems wherein an output of device A is directly connected to an input of device B. It means that there exists a path between an output of A and an input of B which may be a path including other devices or means. ‘Connected’ may mean that two or more elements are either in direct physical or electrical contact, or that two or more elements are not in direct contact with each other but yet still co-operate or interact with each other.

Reference throughout this specification to ‘one embodiment’ or ‘an embodiment’ means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases ‘in one embodiment’ or ‘in an embodiment’ in various places throughout this specification are not necessarily all referring to the same embodiment, but may refer to different embodiments. Furthermore, the particular features, structures or characteristics of any embodiment or aspect of the invention may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

Similarly, it should be appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

Furthermore, while some embodiments described herein include some features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form yet further embodiments, as will be understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practised without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

In the discussion of the invention, unless stated to the contrary, the disclosure of alternative values for the upper or lower limit of the permitted range of a parameter, coupled with an indication that one of said values is more highly preferred than the other, is to be construed as an implied statement that each intermediate value of said parameter, lying between the more preferred and the less preferred of said alternatives, is itself preferred to said less preferred value and also to each value lying between said less preferred value and said intermediate value.

The use of the term ‘at least one’ may, in some embodiments, mean only one.

The invention will now be described by a detailed description of several embodiments of the invention. It is clear that other embodiments of the invention can be configured according to the knowledge of persons skilled in the art without departing from the underlying concept or technical teaching of the invention, the invention being limited only by the terms of the appended claims.

In FIG. 1 an air movement 10 is shown. The system 10 is installed in a series of two rooms 20, 30. The system 10 comprises an exhaust fan 40 at one end of a main duct 50 which extends through one of the room 20. The fan 40 is located outside the room 20 but it could be positioned in the body of the wall, or inside the room 20.

An air inlet 25 is provided in an external wall of the room 20.

In the room 20, five work stations 60 are located. Each work station creates fumes, dust and or heat and needs air extraction from its locale. This is effected by extraction points 70 provided adjacent each work station 60. The extraction points are linked to the main duct 50 such that any fumes, dust or heat is sucked into the duct and expelled from the room via the fan 40.

The air flow through each extraction point 70 is regulated by a damper or valve 80 provided in the main duct 50 adjacent each extraction point 70.

Each damper 80 is controlled by the controller 120. The dampers are linked to the controller 120 by means of control wiring 125, although wireless connections are also contemplated.

The controller 120 is pre-programmed to open each damper 80 as required and in the light of signals generated by each sensor 90, 110 located adjacent each work station 60.

Each sensor 90 may have a wireless link to the controller 120. However, wired connections are also contemplated with some sensors 110.

Each sensor may be of the type that directly detects the presence of personnel such as a PIR, or may be a current detector 110 detecting when the actual work station is in use. For instance, when a lathe is switched on the current change in the electrical supply is detected. Other types of sensor such as temperature gauges, sound detectors are also envisaged. A simple switch may also be incorporated if necessary. More than one type of sensor may be located adjacent each work station 60.

In the adjacent room 30 a branch duct 55 off the main duct 50 provides a route for extracting air from the room 30. There are three extraction points 70 shown. A sensor 100 detects the presence of personnel in the room. The sensor 100 is connected by wire 125 to the controller 120.

A damper 85 is provided at the point where the branch duct 55 extends away from the main duct 50. In this way if the pre-programming of the controller dictates that no extraction is to take place from the room 30 if it has been empty for more than 15 minutes then the controller may close the damper 55 in the branch duct thus isolating that room from the rest of the system. In this way, the fan speed may be reduced as less air requires moving. Moreover, by closing the branch duct 55 at a point near to the main duct 50 there will be less losses due to friction as otherwise the branch duct may be regarded as ‘dead-leg’.

The controller may be pre-programmed such that a minimum airflow is always maintained through the main duct 50 even when no work stations 60 are in use. To effect this the controller runs the fan at a set speed and keeps open a predetermined number of dampers 80, even if only slightly open. The dampers may be regarded as booster dampers and it may be the two on the left hand side of FIG. 1.

When all personnel have gone home at the end of a working day, the controller 120 may be pre-programmed so that it only turns off the fan completely fifteen minutes after the last personnel presence has been detected, or other such signal has stopped being transmitted by any of the sensors.

In the morning, before the working day starts, the controller may be pre-programmed to undertake a clean of the system by opening all dampers fully and running the fan at maximum speed for a predetermined time period such as five minutes. The system may then return to a stand-by mode where a minimum air flow is maintained by keeping two dampers open and a the fan set at a relatively slow speed.

In FIG. 2, an alternative system 210 is shown. This system is based on an example hotel floor comprising six bedrooms 220, three on each side of a corridor 228. Each bedroom 220 has an en-suite bathroom 222.

Each bathroom 222 has an extraction point 270. Each bedroom has a supply point 272. Each bedroom and bathroom also has a sensor 100. The sensors are connected to the controller (not shown) by wiring 125, although wireless connections are contemplated.

Each supply 272, or exhaust 270 point is connected by branch ducting 254, 256 to main ducts 250, 252. The main ducts 250, 252 are located above the corridor 228 separating the two sets of bedrooms 220.

One of the main ducts 250 is the exhaust duct extracting air from the bathrooms by means of a fan 240 located in the duct 250 and forcing it out into the atmosphere.

The other main duct 252 is the supply duct bringing in fresh air from outside. A heat exchanger may be employed to recover heat from the extracted air before it leaves the building and transfer it to the incoming fresh air.

Each branch duct 254, 256 includes a damper 280, 282 such that each bedroom 220 and bathroom 222 may be independently isolated from or connected to the main ducts 250, 252 as required by the controller.

In a similar manner to the system described with reference to FIG. 1 the sensors 100 provide basic information to the controller about the state of each room. The sensors may be PIR, temperature, humidity and so on. More than one type of sensor may be present in each room.

In this way, rooms that are not in use may be left without air movement, or with only minimal air flow from the bedroom to the bathroom. By contrast, rooms in use may have greater airflow. The airflow in each bedroom may be controlled to a certain extent by an occupant of the room with an override controller (not shown).

It will be understood that only a portion of a fully integrated system which would be required in a hotel is shown in FIG. 2. Other supply and extraction points may be located in the corridor 228. The main ducts 250, 252 may connect with ducts in other parts of the hotel and on other floors. This is why the main ducts 250, 252 are shown open-ended. Ducts will be closed at their ends if no connections to other ducts are required. More than one fan in each duct 205, 252 may be required especially if the duct lengths are relatively long.

The controller may be pre-programmed to increase air movement in all rooms every morning, or only in rooms marked as being occupied the night before, or for the night coming. Accordingly, the system may include apparatus for the room allocations to be integrated into the controller such that a receptionist may update the controller as people check-in and check-out of the hotel. In this way the efficiency of the air movement system is optimised.

In any embodiment, various devices may be grouped together at least for the purpose of identification by the controller. For instance, in a relatively large network a fan, several dampers and several associated sensors may be grouped together in one group, and another fan and several other dampers and sensors may be grouped together in another group. The controller may then be pre-programmed to use different settings (such as predefined thresholds, rules etc.) to control each group (or ‘sub-system’). In this way, more fine control of the overall system is possible.

The system may have one of the following states:

Standby—(when no work is occurring) in which all fans and the filter are off to save energy;

Clean—(used to clean the ducting) in which all fans are running at the maximum limit set by the installation engineer and all dampers open. The clean state can operate on start-up and/or on schedule and/or before entering standby;

User Override—in which the system suspends all judgment and allows the user to specify the exact state of all devices;

Operational Default—in which the system extracts or provides air but has not yet been configured for energy saving running;

Operationally Optimised—in which the system has been configured and the controller can make decisions based on its pre-programming as to how the individual devices should be set.

An example of the underlying concept for pre-programming of the controller for the operationally optimised state is as follows.

Pre-Conditions: As part of system commissioning the following must be completed to enable the algorithm to run:

1. A fan (either one of the variable ones or the single fixed speed fan) has been designated as the primary fan;

2. If the pressure sensor is fitted then it has been configured with its measurement range so that % readings can be converted to Pa;

3. If the pressure sensor is fitted then it has been configured with a minimum and maximum target setting. The midpoint of this band is the desired value for optimal efficiency;

4. The primary fan (if variable) has been chosen to either be controlled according to the measures air pressure in the main duct (requires sensor) or by the number of dampers open;

5. The primary fan (if variable) adjustment method been chosen to be either stepwise increments or a single-step (which may require calibration);

6. Device groups have been created in the system configuration to create system nodes which can be locally optimized to give fine-grained optimization;

7. All devices (dampers, the fixed speed fan, variable fans etc.) except the primary fan, the filter and the pressure sensor have been allocated to a device group;

8. The main duct has been configured with its cross-sectional surface area (calculated from either a diameter or a length and width);

9. All dampers have been configured with cross-sectional surface area (calculated from either a diameter or a length and width);

10. All variable speed fans have been given their max kW output in the system configuration so that % utilization can be converted to kW;

11. All variable speed fans have been given their minimum utilization level. This ensures that a fan is always on ‘enough’ even when workload is low;

12. If the adjustment of the primary fan is single-step then the calibration cycle must have been run which measures system behaviour to learn how to adjust the fan to hit the target pressure in a single step.

Claims

1. An air movement system programmable controller for operating an air movement system, the air movement system comprising:

at least one fan;

a plurality of exhaust and/or supply points connected to the at least one fan by ducting;

a plurality of dampers, each damper associated with one of the at least one exhaust and/or supply points, each damper for regulating air flow through the respective associated exhaust and/or supply point; and

a plurality of sensors, each sensor associated with either: one of the at least one exhaust and/or supply points for sensing a predefined activity within a predefined locale of the at least one exhaust and/or supply points; or a predefined point in the ducting;

wherein the programmable controller is connectable to the fan, the dampers and the sensors, and is configured to: automatically adjust the damper associated with one of the at least one exhaust and/or supply points; and adjust the at least one fan; in response to a signal generated by the sensor associated with the same one of the at least one exhaust and/or supply points.

2. The air movement system programmable controller of claim 1, further configured to:

determine if the at least one fan is fixed-speed or variable-speed;

determine which dampers are open;

receive a signal generated by the plurality of sensors, the signal indicative of a sensed predefined activity;

in response to a determination that the at least one fan is a fixed-speed fan, operate the at least one fan in accordance with a pre-set rule, the pre-set rule selected from a plurality of pre-set rules in response to a determination as to which dampers are open, and in response to a reception of the signal indicative of the sensed predefined activity; and

in response to a determination that the at least one fan is a variable-speed fan, operate the at least one fan such that the speed of the at least one fan is set to be approximately proportional to the ratio of the total cross-sectional area of all of the plurality of dampers that are open to the cross-sectional area of a predefined duct.

3. The air movement system programmable controller of claim 1, wherein the controller is configured to automatically adjust at least one damper and the at least one fan to maintain a minimum or maximum airflow through the air movement system at predetermined times of day and for a predetermined period of time regardless of sensed activity or inactivity.

4. The air movement system programmable controller of claim 1, wherein the controller includes an override setting such that each damper and the at least one fan are controllable individually and distinct from any pre-programming.

5. The air movement system programmable controller of claim 3, wherein the controller includes a pre-determinable time period after which the override setting will be cancelled returning the controller to run in accordance with its pre-programming.

6. The air movement system programmable controller of claim 1, wherein the controller is configured to prevent the fan being operated at a predetermined volume-flow rate when a predetermined number of dampers are in the closed position.

7. The air movement system programmable controller of any preceding claim, including a memory for storing system events over time.

8. The air movement system programmable controller of claim 1, including a filter for filtering air as it passes into or out of the air movement system.

9. The air movement system programmable controller of claim 8, wherein the filter is connected to the controller.

10. The air movement system programmable controller of claim 1, wherein the sensors are any one or more of a PIR, a pressure sensor, a temperature sensor, a current sensor and a switch.

11. A method of operating an air movement system comprising the steps of:

providing an air movement system comprising: at least one fan; a plurality of exhaust and/or supply points connected to the at least one fan by ducting; a plurality of dampers, each damper associated with one of the at least one exhaust and/or supply points, each damper for regulating air flow through the respective associated exhaust and/or supply point; and a plurality of sensors, each sensor associated with either: one of the at least one exhaust and/or supply points for sensing a predefined activity within a predefined locale of the at least one exhaust and/or supply points; or a predefined point in the ducting;

providing an air movement system programmable controller according to any one of the preceding claims; and

operating the programmable controller to automatically adjust the damper associated with one of the at least one exhaust and/or supply points, and adjust the at least one fan, in response to a signal generated by the sensor associated with the same one of the at least one exhaust and/or supply points.

12. The method of claim 11, further comprising the steps of:

determining if the at least one fan is fixed-speed or variable-speed;

determining which dampers are open;

receiving a signal generated by the plurality of sensors, the signal indicative of a sensed predefined activity;

in response to a determination that the at least one fan is a fixed-speed fan, operating the at least one fan in accordance with a pre-set rule, the pre-set rule selected from a plurality of pre-set rules in response to a determination as to which dampers are open, and in response to a reception of the signal indicative of the sensed predefined activity; and

in response to a determination that the at least one fan is a variable-speed fan, operating the at least one fan such that the speed of the at least one fan is set to be approximately proportional to the ratio of the total cross-sectional area of all of the plurality of dampers that are open to the cross-sectional area of a predefined duct.

13. The method of claim 12, wherein if the ratio is less than a predefined threshold value the fan is operated at a pre-set speed.

14. The method of claim 12, wherein the predefined duct is the main intake and/or exhaust duct.

15. The method of claim 12, wherein the air movement system includes a filter and the method further comprises the steps of determining if the at least one fan is operational and operating the at least one fan in accordance with said determination.