WO2009081127A1

WO2009081127A1 - A light well ventilator

Info

Publication number: WO2009081127A1
Application number: PCT/GB2008/004207
Authority: WO
Inventors: Andrew Woods
Original assignee: E-Stack Ltd
Priority date: 2007-12-21
Filing date: 2008-12-18
Publication date: 2009-07-02
Also published as: GB0725154D0; GB2455813A

Abstract

A light well ventilator for disposal in a ceiling void or roof void of a room, building or the like comprises an inner housing defining a first interior space and having a first opening for the passage of airflow between the first interior space and the room, building or the like, a second opening for allowing airflow to pass between the first interior space and the exterior atmosphere, an outer housing arranged to surround the inner housing so as to define a second interior space between the inner housing and outer housing, the second interior space comprising a third opening to allow the passage of airflow between the room, building or the like and the second interior space, the inner housing having at least one perforation therein for transfer of airflow between the first interior space, and the second interior space a power source for assisting the passage of airflow through the inner housing and a control system for controlling the power source and/or the size of at least the second opening.

Description

A LIGHT WELL VENTILATOR

The present invention relates to a light well ventilator for a room, building or the like, and to a method of operating a light well ventilator.

In buildings such as residential housing, it can often be desirable to increase the light level into an otherwise dark or shaded room, particularly north facing rooms. One way of achieving this is by using a window such as a Velux ™ window or light well that can be installed in a roof, for example in order to increase the level of light within the room. Such windows may also be opened in order to provide a fresh inflow of air into the room. However, these windows provide no means of regulating the temperature of the air that flows into the room from the exterior atmosphere. Particularly in winter, this can mean an inflow of uncomfortably cold air into the room. In situations such as this, some form of heating equipment may be necessary in the vicinity of the window in order to pre-heat the cold incoming air. This is costly and can be a noisy, energy inefficient solution.

It is therefore desirable to produce a solution that can provide both controlled natural light and ventilation into a room or building without the need for additional heating equipment in the vicinity of the unit.

According to a first aspect of the present invention, there is provided a light well ventilator for disposal in a ceiling void or roof void of a room, building or the like, the light well ventilator comprising: an inner housing defining a first interior space and having a first opening for the passage of airflow between the first interior space and the room, building or the like, a second opening for allowing airflow to pass between the first interior space and the exterior atmosphere; an outer housing arranged to surround the inner housing so as to define a second interior space between the inner housing and outer housing, the second interior space comprising a third opening to allow the passage of airflow between the room, building or the like and the second interior space; the inner housing having at least one perforation therein for transfer of airflow between the first interior space and the second interior space; a power source for assisting the passage of airflow through the inner housing; and a control system for controlling the power source and/or the size of at least the second opening.

An advantage of this light well ventilator is that cooler ventilation air entering the light well from outside is able to mix in the first interior space with warmer air from the room or building to be ventilated and lit, such that ventilation air is provided to the room at a controlled temperature that is comfortable to the occupants of the room, without the need for electrical or other form of heating to pre-heat the ventilation air. This in turn can make the light well ventilator cheap to operate. The light well ventilator may further comprise at least one sensor locatable in the room, building or the like to be ventilated. The sensor may be a temperature sensor for measuring the temperature inside the room. A further sensor may comprise a CO₂ sensor for measuring CO₂ concentration level in the room. There may also be provided a further temperature sensor for measuring the exterior temperature. In this manner, the level of ventilation and level of natural light entering the room is controllable based on pre-determined levels of comfort inside the room to be lit/ ventilated.

The second opening may be at least partially transparent. It may include a controllable covering that may be controlled according to the input from a light sensor within the room. In this manner, the covering or blind may be used to mitigate the ingress of solar radiation in high summer, and to enable natural light to enter the room in winter.

The first opening and the third opening of the light well ventilator may comprise a perforated member such as a grille or punched metal sheet. Thus the first and third openings may comprise multiple small openings in order to allow the passage of air between the room and the light well structure. The inner housing may have multiple perforations in order to distribute the passage of airflow between the second interior space and the first interior space. The multiple perforations may be evenly distributed about the housing wall.

The second opening may be an actuatable window. The third opening may be variable in size, based on an input to the control system from the one or more sensors.

A second power source may be provided that is in spaced relationship from the first power source inside the first interior space. In this embodiment, one power source or fan would operate to draw cool air into the first interior space from the outside whilst the second fan may operate to draw warm air up from the room into the first interior space. In this embodiment, the two airstreams meet in the first interior space of the inner housing where they are pre-mixed, following which the mixed airstream is able to flow out through the perforated wall of the inner housing, and to sink down through the third opening into the room, building or the like to provide pre-warmed ventilation air.

According to a second aspect of the invention, there is provided a method of operating a light well ventilator, the light well ventilator comprising an inner housing defining a first interior space and having a first opening to allow passage of airflow between the first interior space and the room, building or the like, a second opening for allowing airflow to pass between the interior space and the exterior atmosphere; an outer housing arranged to surround the inner housing so as to define a second interior space between the inner housing and the outer housing, the inner housing having at least one perforation therein for transfer of airflow between the first interior space and the second interior space; and a power source for assisting passage of airflow through the inner housing, the method comprising the steps of controlling the size of the second opening and controlling the power source to either: draw in exterior air through the first interior space such that the incoming exterior air is able to mix with a second warmer airstream entering the second interior space from the room, building or the like and passing through the at least one perforation into the first interior space, the pre-mixed exterior air and warmer air providing warmed ventilation air to the room, building or the like; or to draw in warm room air into the first interior space so as to expel excess heat from the room, building or the like into the exterior atmosphere.

These and other aspects of the invention will become apparent to the skilled person upon reading the following description of preferred embodiments of the invention that will now be described by way of example only with reference to the accompanying drawings, in which:

Figure 1 shows a first embodiment of a light well ventilator in accordance with the invention, operating in a "winter" mode;

Figure 2 is a schematic view of the light well ventilator of Figure 1, operating in a "summer" mode; and Figure 3 is a schematic view of a second embodiment of a light well ventilator in accordance with the invention.

Referring to Figure 1, a room or building 10 includes a ceiling 12 at the top thereof. The building further comprises a roof 15, spaced from the ceiling 12 to define a roof or ceiling void 20. Installed in the roof or ceiling void 20 is a light well ventilator 30. The light well ventilator 30 comprises an outer cylindrical housing 35 and an inner cylindrical housing 40, the two cylindrical housings being mounted co-axially such that the outer cylindrical housing 35 surrounds the inner cylindrical housing 40. A first interior space 50 is defined inside the inner cylindrical housing 40. A second annular interior space is defined in the gap between the walls of the outer cylindrical housing 35 and the inner cylindrical housing 40. The first interior space 50 and the second annular interior space 60 each extend the length of the light well ventilator. At a lower end of the first interior space 50, there is provided a grille or perforated sheet 65 that provides an opening between the room or building and the inner cylindrical housing. At an upper end of the first interior space 50, the inner cylindrical housing 40 is terminated by an actuatable window 70 that seals the inner cylindrical housing from the atmosphere when it is closed and which when open provides ventilation air to the first interior space 50. The window is transparent and thus also provides natural light from the exterior into the first interior space 50 and thus into the room or building 10, via the grille or perforated sheet 65. Although the inner housing and outer housing of the light well ventilator of the present embodiment are described as being cylindrical in shape, it will be apparent to the skilled person that other shapes, such as but not limited to square or triangular, could also be used. In an embodiment, the inner housing 40 and outer housing 35 may be of different shapes. At a lower end of the second interior space 60, at ceiling level, the housing 35 is open to the room 10, via a grille or perforated sheet 75. At an upper end of the second interior space 60, the housing 35 is sealed from the atmosphere. The inner housing 40 includes at least one, preferably multiple perforations 80, allowing the passage of air between the first and second interior spaces, 50,60. In this manner, air flowing into the second interior space 60 from the room or building 10 must flow through the perforations into the first interior space 50.

The window 70 includes a blind or other covering 85 that is permeable to airflow but may be used to screen the ingress of sunlight into the light well ventilator when desired.

A power source e.g. a fan 90 is provided at the lower end of the first interior space 50 in order to assist the drawing of air either from the room or from the exterior into the first interior space, depending upon a direction of rotation of the fan.

A temperature sensor 105 is located in the room or building 10 in order to measure the room temperature. A second temperature sensor 120 is located on the roof 15 at the exterior of the light well ventilator for measurement of the exterior temperature. In the present embodiment, a CO₂ sensor 110 is also present in the room or building 10. The measurements recorded by each of the sensors 105,110 and 115 are used as input data into an algorithm for controlling the size of the opening 71 formed by opening or closing the window 70 to a lesser or greater extent. The algorithm computes the desired extent of opening of the window 70 that will provide enough ventilation air through the opening 71 and into the first interior space 50. The algorithm also computes whether the fan 90 should be operated in order to assist the drawing of cooler ventilation air through the opening 71 in "winter mode", or in "summer mode" to draw warm air upwards from the room 10. The output of the algorithm is used by a controller 100 to operate an electric stepper motor or other control device to adjust the window 70 and the operation of the fan 90.

In the so-called "winter mode", operation of the light well ventilator is as follows. If the window 70 is in the closed position, there is no inflow of air from the outside into the first interior space 50. The fan 90 may be operated to pull airflow down into the room 10 from the first interior space 50. Warm air from the room 10 flows upwards through the grille member 75 into the second interior space 60. From there, the air may flow through the perforations 80 into the first interior space 50, where the fan 90 will then re-circulate the air back into the room. However, if the window 70 is open, as shown in Figure 1, operation of the fan 90 also acts to draw in cold air from the exterior into the first interior space 50, where it mixes with the warmer room air, pre-mixing the colder exterior air to a comfortable temperature. The pre-mixed air is then able to sink through the grille or perforated member 65 into the room 10 below where it provides warmed ventilation air at a comfortable temperature to the occupants of the room or building 10. Throughout operation of the winter mode, the covering 85 may be drawn back so as to allow the maximum possible natural light through the window 70 and into the first interior space 50 and thus into the room or building 10 via grille member 65. The controller 100 may operate the covering or blind 85 based on input data from a light sensor 130 present in the room or building 10.

In the so-called "summer mode" the window 70 is open at least to an extent. The fan 90 may be operated in a reversed direction from the winter mode such that it acts to draw air up from the room 10, through the grille 65 and into the first interior space 50. From here, the warm air rises and exits the light well ventilator via the opening 71. However, a percentage of the air rising through the first interior space 50 may seep through the perforations 80 in the inner cylindrical housing 40 and flow back through the second interior space 60 and through the grille 75 into the room 10. The air may also flow up from the room, through the grille 65 and into the second interior space 60, depending on how quickly the fan operates compared to the natural buoyancy of the upflow or to e.g. wind driven upflow. From the second interior space 60, the air flows through the perforations 80 into the first interior space where it exits the light well ventilator via the opening 71. In the summer mode, the light sensor 130 may detect a higher than desirable threshold of solar radiation incoming through the window 70 and accordingly the blind 85 may be fully or partially drawn.

In either winter or summer mode, the light well ventilator is operated by a control algorithm, which the skilled person will appreciate may take various forms, one of which is as follows.

Step 1: Check room temperature at sensor 105 and check CO₂ concentration in room at sensor 110. If room temperature exceeds 24°C or if CO₂ concentration exceeds 800ppm (parts per million), then check external temperature at sensor 120.

Step 2: If external temperature measured at sensor 120 is below a predetermined threshold (e.g. 17°C), open the window 70 and turn on the fan 90 in downflow mode (winter mode).

Step 3: If the external temperature measured at sensor 120 is above the predetermined threshold (e.g. 17°C), open the window 70 and turn on the fan in upflow mode (summer mode). Step 4: If the room temperature is measured at sensor 105 to be lower than a desired comfort threshold (e.g. 19°C), and if CO₂ concentration is within a desired range (e.g. ≤ 800ppm), close the window 70.

Step 5: If room temperature and CO2 measurements are within the desired range, turn off the fan 90 and close the window 70.

Step 6: Check the solar radiation level at sensor 130 and if too high, close blind 85.

Step 7: Re-check status of system every five minutes.

It will be apparent to the skilled person that the details of the desired threshold, repeat times for measurements and also the number of repeat measurements that will be required in order to trigger a change to the operation of the light well ventilator are variable, and that the above algorithm is illustrative only. The skilled person in the art will appreciate that there are many ways of programming such an algorithm and that these are conventional in the art and will not be described here.

In a second embodiment, the light well ventilator may include a second fan located in an upper region of the first interior space 50, in addition to the first fan 90. The fans will operate in opposing directions relative to each other. For example, if fan 90 is rotated to operate as shown in Figures 2 and 3, it will draw air upwards from the room 10, through the grille 65 into the first interior space 50. Meanwhile, the contra-rotating fan 95 will draw in cooler exterior air through the opening 71 , where it will be mixed with the warm room air in the first interior space 50. The pre-mixed ventilation air will then be able to escape through the perforations 80 in the wall of the inner cylindrical housing 40, from where it sinks downwards through the grille 75 and into the room or building 10, providing controlled temperature regulated ventilation air, removing the need for mechanical heating of the inflowing air. The blind 85 may be opened or closed according to solar radiation levels read by the light sensor 130.

The light well ventilator can also be operated in "summer mode" in which the two fans 90,95 are operated in co-rotation such that each fan draws air from the room, through the grille 65 into the first interior space 50 and out of the light well ventilator at opening 71.

In an embodiment, the light well ventilator is powered by a solar panel 145 (shown in Fig. 3) at the exterior of the room, building or the like in which the light well ventilator is installed. For example, any one or all of the fans 90,95 the actuation of the window 70 or of the blind 85 may be powered by the solar panel 145.

The term "opening" will be understood by the skilled person to include an aperture or a series of apertures, the size of which is or may be variable to control flow rate therethrough. The grille member 65 and/or 75 may however be replaced by a simple opening without departing from the scope of the invention as claimed.

In each of the embodiments described above, the light well ventilator is shown in a vertical orientation. However, it need not be so and the first, second and third openings need not be vertically displaced with respect to one another.

The light well ventilator may be mounted at a location other than in the roof of a building. It could for example be installed in a wall of the building 10. The light well ventilator may be an integral part of the building design or it may be added later as a retro-fit.

Various modifications may be made to the embodiments described without departing from the scope of the invention as defined by the following claims.

Claims

1. A light well ventilator for disposal in a ceiling void or roof void of a room, building or the like, the light well ventilator comprising: an inner housing defining a first interior space and having a first opening for the passage of airflow between the first interior space and the room, building or the like, a second opening for allowing airflow to pass between the first interior space and the exterior atmosphere; an outer housing arranged to surround the inner housing so as to define a second interior space between the inner housing and outer housing, the second interior space comprising a third opening to allow the passage of airflow between the room, building or the like and the second interior space; the inner housing having at least one perforation therein for transfer of airflow between the first interior space and the second interior space; a power source for assisting the passage of airflow through the inner housing; and a control system for controlling the power source and/or the size of at least the second opening.

2. A light well ventilator as claimed in claim 1, further comprising at least one sensor locatable in the room, building or the like to be ventilated.

3. A light well ventilator as claimed in claim 2, in which the sensor is a temperature sensor.

4. A light well ventilator as claimed in claim 3, further comprising a CO₂ sensor locatable in the room, building or the like to be ventilated.

5. A light well ventilator as claimed in claim 1, in which the second opening is at least partially transparent.

6. A light well ventilator as claimed in claim 5, in which the second opening includes a controllable covering actuatable to vary exposure of the second opening to the room, building or the like.

7. A light well ventilator as claimed in claim 6, further comprising a light sensor, the output of which provides an input to the control system to determine actuation of the controllable covering.

8. A light well ventilator as claimed in any of claims 1-7, in which the first opening and the third opening each comprise a perforated member.

9. A light well ventilator as claimed in any of claims 1-8, in which the size of the third opening is variable.

10. A light well ventilator as claimed in claim 1 in which the inner housing includes multiple perforations therein.

11. A light well ventilator as claimed in claim 5 in which the second opening is an actuatable window.

12. A light well ventilator as claimed in any preceding claim, further comprising a second power source arranged inside the first interior space in a spaced relationship from the first power source.

13. A light well ventilator as claimed in any preceding claim in which the inner housing and outer housing are cylindrical in shape.

14. A light well ventilator as claimed in claim 13 in which the inner housing is located generally co-axially with the outer housing.

15. A method of operating a light well ventilator, the light well ventilator comprising an inner housing defining a first interior space and having a first opening to allow passage of airflow between the first interior space and the room, building or the like, a second opening for allowing airflow to pass between the interior space and the exterior atmosphere; an outer housing arranged to surround the inner housing so as to define a second interior space between the inner housing and the outer housing, the inner housing having at least one perforation therein for transfer of airflow between the first interior space and the second interior space; and a power source for assisting passage of airflow through the inner housing, the method comprising the steps of controlling the size of the second opening and controlling the power source to either draw in exterior air through the first interior space, such that the incoming exterior air is able to mix with a second warmer airstream entering the second interior space from the room, building or the like and passing through the at least one perforation into the first interior space, the pre-mixed exterior air and warmer air providing warmed ventilation air to the room, building or the like; or to draw in warm room air into the first interior space so as to expel excess heat from the room, building or the like into the exterior atmosphere.

16. The method of claim 15, in which the step of controlling the size of the second opening and controlling the power source based upon an input from at least one sensor locatable in the room, building or the like.

17. A method as claimed in claim 16, in which the sensor is a temperature sensor.

18. A method as claimed in claim 16, in which the sensor is a CO₂ sensor.

19. The method of claim 15, in which the light well ventilator further comprises a covering for the selective prevention of the ingress of solar radiation into the second opening, the method further comprising the step of controlling usage of the covering depending on an input from a further sensor.

20. A method as claimed in claim 19, wherein the further sensor is a light sensor.

21. A method as claimed in claim 15, in which the light well ventilator further comprises a third opening providing fluid communication between the second interior space and the room, building or the like, the method further comprising the step of controlling the size of the third opening to regulate a rate of airflow passing therethrough.

22. A method as claimed in any preceding claim in which the light well ventilator is powered by a solar panel.

23. A room, building or the like, including a light well ventilator as claimed in any of claims 1 to 14 installed therein.

24. A room, building or the like as claimed in claim 23, further comprising a solar panel disposed at an exterior thereof for providing power to the light well ventilator.