Ventilation system

Abstract

A ventilation system for ventilating a room, comprising: a lowered ceiling, defining a ceiling space between the lowered ceiling and a ceiling of the room and having an air permeable ceiling surface area; a raised flooring, supported by a support frame and defining a floor space between the raised flooring and a floor of the room, the raised flooring being air permeable over a floor surface area opposite to the air permeable ceiling surface area; an air supply inlet connected to the floor space; and an air outlet, connected to the ceiling space, wherein the air permeability of the raised flooring varies in dependence on distance from the air supply inlet for forming a substantial vertical air flow in which air entering the room through the floor surface area displaces air in the room in the vertical direction and forces air out through the ceiling surface area.

Claims

1. A ventilation system for ventilating a room, comprising: a lowered ceiling, defining a ceiling space which, when installed, is between the lowered ceiling and a ceiling of the room, the lowered ceiling having a ceiling surface area that is air permeable; a raised flooring, being supported by a support frame, defining a floor space which, when installed, is between the raised flooring and a floor of the room, the raised flooring being air permeable over a floor surface area that is opposite to the air permeable ceiling surface area; an air supply connected with an air supply inlet to the floor space for supplying air into the floor space; and an air outlet, connected to the ceiling space for exiting air from the ceiling space, wherein the air permeability of the raised flooring varies in dependence on distance from the air supply inlet for forming a substantial vertical air flow in which air entering the room through the floor surface area displaces air in the room in the vertical direction and forces air out through the ceiling surface area.

2. The ventilation system according to claim 1, wherein the raised flooring comprises a plurality of floor tiles with through-holes, wherein the number of through-holes per cm.sup.2 and/or size of the through-holes is adapted as a function of the distance from the air supply inlet.

3. The ventilation system according to claim 2, wherein each floor tile is provided with a moveable blocking member that is displaceable along a surface area of the tile for at least partly blocking off the through-holes.

4. The ventilation system according to claim 3, wherein each floor tile further comprises a pressure sensor for sensing an air flow pressure through the floor tile and an electric actuator arranged for displacing the blocking member along the surface area of the tile, and wherein the ventilation system further comprises a controller which is with an input connected to each sensor, for receiving a measured pressure value, and adapted for determining an air pressure distribution over the surface of the flooring surface area, and which controller is with an output connected to each electric actuator, and adapted for operating each electric actuator to displace the blocking member adjusting the size of the through-holes of a respective floor tile in dependence of the received pressure value of the respective floor tile and the calculated pressure distribution.

5. The ventilation system according to claim 3, wherein each floor tile is provided with upper through-openings of a first diameter in a predefined pattern and wherein the blocking member is provided with lower through-openings in a predefined pattern matching the predefined pattern of the upper through-openings, each lower through-opening having a second diameter which is larger than the first diameter or being slot-shaped, having a length which is larger than the first diameter and a width at least equal to the first diameter, the upper and lower through-openings forming the through-holes of the floor tile.

6. The ventilation system according to claim 2, wherein each of the through-holes in each floor tile is provided with a logarithmic valve for automatically adjusting a size of the through-opening in dependence on air pressure.

7. The ventilation system according to claim 1, wherein the raised flooring comprises a sound proofing material, which in the floor surface area forms a resistance against air flow through the floor surface area and varies in thickness and/or density as a function of the distance from the air inlet; and/or is provided with through-holes, wherein the number of through-holes per cm2 and/or size of the through-holes is adapted as a function of the distance from the air supply inlet.

8. The ventilation system according to claim 1, wherein the floor surface area of the raised flooring comprises a protective zone, the protective zone having an increased permeability with respect to the surrounding floor surface area.

9. The ventilation system according to claim 2, wherein a section of the ceiling surface area has a permeability that is equal or higher than a section of the floor surface area that is opposite.

10. The ventilation system according to claim 1, further comprising a ventilation unit which comprises the air supply and the air outlet, wherein the air supply comprises an outside-air inlet, arranged for receiving air from an outdoor environment, and an air supply fan, arranged between the outside-air inlet and the air supply inlet, to force air from the outdoor environment to the air supply inlet of the floor space, and wherein the air outlet comprises an inside-air inlet, connected to the ceiling space for exiting air from the ceiling space, an inside-air outlet, connected to the inside-air inlet and arranged for exiting air to the outdoor environment, and an air removal fan, arranged in between the inside-air inlet and the inside-air outlet, to force air from the ceiling space to the inside-air outlet.

11. The ventilation system according to claim 10, wherein the ventilation unit further comprises a filter, arranged between the outside-air inlet and the air supply inlet and adapted to filter the incoming air from contaminants.

12. The ventilation system according to claim 10, wherein the ventilation unit further comprises a mechanical ventilation heat recovery (MVHR) system, connected to both the air supply and the air outlet and adapted to transfer heat from the air outlet to the air supply, and a bypass arranged between the air supply and the MVHR system and to bypass air from the outside environment around the MVHR system when a temperature of air in the air outlet and/or in the air inlet is equal or higher than a predetermined temperature.

13. The ventilation system according to claim 10, wherein the ventilation unit is a modular unit comprising at least four equally sized and shaped modules, preferably eight.

14. The ventilation system according to claim 1, further comprising a diffuser, located at the air supply inlet and adapted to direct incoming air into multiple radial directions in the floor space, such that the incoming air is distributed over the floor space at a predetermined distribution.

15. A floor tile for use in a ventilation system according to claim 1, having a predetermined permeability and sound proofing.

16. The floor tile according to claim 15, comprising a plurality of through-holes, each through hole being provided with a logarithmic valve for automatically adjusting a size of the through-opening in dependence on air pressure on either side of the floor tile.

17. The floor tile according to claim 15, comprising a plurality of through-holes and a moveable blocking member that is displaceable along a surface area of the floor tile for at least partly blocking off the through-holes.

18.-20. (canceled)

21. A set of modules for forming a ventilation unit for use in a ventilation system according to claim 13, the set of modules comprising: a first and a second fan module, each comprising a fan a first and a second inlet module, each comprising an air inlet a first and a second outlet module, each comprising an air outlet, and preferably MVHR system module, comprising a MVHR system and a bypass, wherein the modules are stackable and connectable such that the first inlet module, the first fan module and the first outlet module form an air supply channel and the second inlet module, the second fan module and the second outlet module form an air outlet channel.

22. The set of modules according to claim 21, wherein each module is comprised in a housing, and wherein the housing has a length (L1) equal to the width of two floor tiles and a depth (D1) equal to the width of one floor tile.

23.-25. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Embodiments of . . . according to the present invention will be described by way of example, with reference to the attached drawings, in which:

[0067] FIG. 1 shows a perspective view of a classroom provided with a ventilation system according to the invention;

[0068] FIG. 2A shows a top view of the raised flooring of the ventilation system in FIG. 1;

[0069] FIG. 2B shows a detailed view of section IIB of the raised flooring in FIG. 2A;

[0070] FIG. 3 shows a top view of an embodiment of the lowered ceiling of the ventilation system in FIG. 1;

[0071] FIGS. 4A and 4B show a respective top and bottom perspective view of a floor section for a raised flooring of a ventilation system according to the invention; and

[0072] FIGS. 5A, 5B and 5C show a logarithmic valve for use in a raised flooring of a ventilation system according to the invention under three different air pressure conditions;

[0073] FIG. 6 shows a perspective view of a ventilation unit for use with a ventilation system according to the invention;

[0074] FIG. 7 shows a frontal view of the ventilation unit of FIG. 6;

[0075] FIG. 8 shows a side view of the ventilation unit of FIG. 6;

[0076] FIG. 9 shows an exploded view of the ventilation unit of FIG. 6, showing the individual modules the ventilation unit is made of;

[0077] FIG. 10 shows a perspective view of an office provided with a ventilation system according to the invention; and

[0078] FIG. 11 shows a cross-section of part of the floor space at the air supply, where a diffuser is provided.

DESCRIPTION OF EMBODIMENTS

[0079] FIG. 1 shows a perspective view of a classroom provided with a ventilation system 100 according to the invention, having a wall 9 extending between the floor and the ceiling of the room. The ventilation system in the room 100 is shown to have a raised flooring 10, a lowered ceiling 1 and an air supply inlet 3. The raised flooring 100 and lowered ceiling 1 are both air permeable over surface areas which are located opposite one another, covering a substantial surface area of the respective floor and ceiling of the room and being substantially parallel thereto. Due to the raised flooring and lowered ceiling, the room is vertically divided into three volumes: a floor space, between the floor of the room and the raised flooring 10, a user space for use of the room, extending between the raised flooring 10 and the lowered ceiling 1, and a ceiling space, between the lowered ceiling 1 and the ceiling of the room. The air supply inlet 3 is connected to the floor space for supplying fresh air from the buildings air-conditioning system. The air permeability of the raised flooring 10 varies in dependence on distance from the air supply inlet 3 for forming a substantial vertical air flow entering the user space of the room through the raised flooring 10 having a substantially even flow rate over the permeable floor surface area. This causes the incoming fresh air to displace the air already present in the user space of the room vertically, forcing it towards the lowered ceiling 1 and through the lowered ceiling surface area for exiting the room.

[0080] Through varying the air permeability of the raised flooring 10 in dependence on distance from the air supply inlet 3, the air entering the room through the raised flooring has substantially the same flow rate over the whole floor surface area substantially the same volume and flow speed, causing a vertical laminar flow of fresh air entering the room via the floor. The directly opposite permeable ceiling surface area allows the vertical laminar flow of fresh air being maintained substantially vertical and laminar over the entire height of the room between the raised flooring 10 and lowered ceiling 1, preventing the mixing of air due to ventilation and minimizing transverse movement of aerosols inside the room, for example due to persons moving through the user space.

[0081] In the classroom, on the raised flooring 10, desks for pupils 91 and a teachers desk 90 are placed. In order to further prevent the chances of transverse spreading of aerosols between, for example, pupils and teacher, or to a specific pupil, the permeability of the raised flooring immediately under and around their desks 90, 91 may be increased with respect to the surrounding raised flooring, providing a protective zone. In this protective zone, the vertical laminar air flow is increased with respect to the vertical laminar air flow in the rest of the user space of the room, effectively creating a curtain-effect preventing substantially all air transfer from the rest of the user space of the room into the protective zone.

[0082] Although the example in FIG. 1 shows a classroom, the same ventilation system may be used in any room and protective zones can be set up where and as desired.

[0083] FIG. 2A shows a top view of the raised flooring 10 of the ventilation system in FIG. 1, with FIG. 2B showings a detailed view of section IIB thereof. The raised flooring 10 has an air permeable surface area consisting of floor tiles 11. The number of through-holes per cm.sup.2 in each tile 11 is increased with increasing distance d1, d2 from the air supply inlet 3. In order to install the raised flooring 10, a lay-pattern of floor tiles 11 having varying amounts of through-holes per cm.sup.2 needs to be determined, based on the dimensions of the room and the required air refreshing rate thereof. To facilitate easy installation of the raised flooring 10, a set of floor tiles 11 may be provided wherein each of the floor tiles 11 is provided with an ID related to a row number with respect to the air inlet and a position within that row from one side of the raised flooring 10.

[0084] Providing floor tiles 11 with through-holes is a relatively easy manner of obtaining tiles with a predetermined and constant air permeability. Additionally or alternatively, the size of the through-holes may adapted as a function of the distance from the air supply inlet 3. The size of the through-holes may be made adjustable such that a single tile design can be used for the entire raised flooring, removing the requirement of designing a predetermined lay-pattern for each specific room. Such tiles are described in more detail in relation to FIGS. 4A 4B and 5.

[0085] FIG. 3 shows a top view of the lowered ceiling 1 of the ventilation system 100 in FIG. 1. Similar to the raised flooring 10, the lowered ceiling 1 has an air permeable surface area consisting of tiles 5. To facilitate the vertical laminar air flow through the user space of the room remaining vertical over the entire height thereof, each section of the ceiling surface area has a permeability that is equal or higher than a section of the floor surface area that is opposite therefrom. Hereto, the depicted ceiling 1 has tiles 5, wherein the number of through-holes per cm.sup.2 in each tile 5 is increased with increasing distance d1, d2 from the air supply inlet 3. Further, the top view of the ceiling 1 shows an air outlet 2, connecting the ceiling space to the outlet of the air-conditioning system for removing the exiting air from the room.

[0086] FIGS. 4A and 4B show a respective top and bottom perspective view of embodiments of a floor section for a raised flooring of a ventilation system according to the invention, the top perspective view of FIG. 4A being similar to the floor tiles with fixed hole size and pitch shown in FIGS. 2A and 2B.

[0087] The floor section in FIG. 4A shows a floor tile 11 with four adjustable supports 12, for forming a supporting frame which supports the raised flooring at a predetermined distance from the floor of a room. The floor tile 11 has a predetermined width W and length L and is provided with a number of through-holes 19 having a hole size Φ.sub.1, which are spaced apart at a fixed width-wise and length-wise pitch dw, dl. At a lower side, the floor tile 11 is provided with a layer of sound proofing material 16, which layer extends over most of the lower side of the floor tile 11. In order not to impact the predetermined air permeability of the floor tile, as provided by the pattern of through-holes, the layer of sound proofing material is provided with a matching pattern of through-holes, having a larger hole size.

[0088] The floor section in FIG. 4B shows a similar floor tile 11′ as the floor tile 11 in FIG. 4A, now from the bottom. Additionally or alternatively to the layer of soundproofing, the floor tile 11′ is provided with a moveable blocking member 16′ that is held in guide rails 13′ to the lower side of the tile 11′ and provided with an electrical actuator in the form of a rack and pinion 22, 21 for displacing the blocking member 16′ in the guide rails, along the bottom surface of the tile 11′. The floor tile 11′ further comprises a pressure sensor 18′, located in a through-hole, for sensing an air flow pressure through the floor tile. The blocking member 16′ is provided with through-holes 19′ in a pattern matching the pattern of through-holes of the tile 11′, i.e. thus the length-wise and width-wise pitch dl′, dw′ of the through-holes in the blocking member 16′ is equal to those of the tile. The size Φ.sub.2 of the through-holes 19′ is larger than the size Φ.sub.1 of the through-holes in the tile 11′. By moving the blocking member 16′, the effective through-hole size of the tile 11′ is adjustable. This adjustability is automated by connecting the electric actuator 21, 22 and the sensor 18′ to a controller (not shown). By connecting all floor tiles 11′ of the raised flooring to the controller, the controller the through-hole size of each floor tile 11′ until the measured flow pressure of each tile is substantially the same.

[0089] Alternatively to an electrically controlled system, the variability of the air permeability of the raised flooring 10 in dependence on distance from the air supply inlet 3 can be automated by fitting each of the through-holes in the tiles with logarithmic valves. FIGS. 5A, 5B and 5C show such a logarithmic valve under three different air pressure conditions. The logarithmic valve comprises a tubular outer body 39 and a flexible inner tube 38, which has a dome-shaped cross-section and is with an upper and a lower side fixed to both ends of the tubular outer body 39, forming the closing member of the valve 19′. As shown in FIG. 5a, when the air pressure on both ends of the valve is equal, the flexible inner tube 38 closes off the valve, such that no though-opening exists and the flow rate O through the valve is zero.

[0090] The dome-shaped flexible inner tube 38 has an opening resistance rate which substantially logarithmically increases at increasing opening. Thus when an air flow of increasing pressure is applied to one side of the valve, the inner tube 38 generates an initial opening O.sub.1 matching a first pressure level F.sub.1 which is lower than the increasing pressure. When the valve is placed between two separate spaces, this causes the pressure inside the space on the inlet side of the valve to rise. Between two connected spaces with a plurality of through-holes and one air inlet, this reduces the effect of pressure drop due to the presence of the opening of the valve and depending on the amount of valves, their pitch and valve properties, all valves may be opened to the same opening size before a further increase in incoming air pressure opens the valves closest to the air supply inlet further. Thus with a sufficient amount of valves provided in the raised flooring, this effect ensures a more homogeneous pressure distribution in the floor space, such that all valves over the floor surface area open to substantially the same size and produce a vertical laminar flow of substantial equal flow rate in the user space.

[0091] A protective zone may be provided by an increased amount of the same logarithmic valves and/or using valves with a lower opening resistance in a predetermined area of the raised flooring, increasing the amount of air outputted into the protective zone with respect to the surrounding floor surface area.

[0092] Although the logarithmic valve is depicted with an inner tube having a dome-shaped cross-section, alternatively shaped valves having the same functionality are known and may be implemented instead. An alternative, well-known, logarithmic valve, for example, comprises a layer of silicon, or other soft flexible material, of predetermined thickness, which covers the through-holes in the floor tile, wherein the layer of material is provided with an x-cut within the circumference of each through-hole. The x-cut provides an opening through the material layer, which opening size depends on the pressure difference between each side of the x-cut and has an opening resistance rate which increases at increasing opening, similar to the depicted logarithmic valve.

[0093] FIGS. 6, 7, 8 and 9 respectively show a perspective view, a frontal view, a side view and an exploded view of a ventilation unit 200 for use with a ventilation system according to the invention. Said ventilation unit 200 is a dedicated ventilation unit dedicated to the ventilation system in a room, such that each room in a building supplied with a ventilation system according to the invention is independently ventilated and cross-contamination between rooms by the ventilation system is fully prevented.

[0094] The ventilation unit 200 as depicted consists of eight modules 201, 202, 203, 204, 205, 206, 207, 208, together comprising air inlet piping Pi, air outlet piping Po, a filter 2016, an air supply fan 212, an air removal fan 214, a bypass 210 and a mechanical ventilation heat recovery (MVHR) system 217. Each module 201, 202, 203, 204, 205, 206, 207, 208 is dedicated to a specific function within the ventilation unit 200, such that there is an outside air inlet module 201 comprising an outside air inlet Ai1, an outside air outlet module 204 comprising an outside air outlet Ao2, an inside air inlet module 208 comprising the air supply inlet 3′, an inside air outlet module 205 comprising the air outlet 2′, an air supply fan module 207 comprising the air supply fan 212, an air removal fan module 203 comprising the air removal fan 214 and two MVHR system modules 202,206 comprising the MVHR system 217 and bypass 210. The modules 201, 202, 203, 204, 205, 206, 207, 208 are stacked together in two columns of equal height.

[0095] The air inlet piping Pi extends between the outside air inlet Ai1, which forms a first air inlet of the ventilation unit 200, and an air supply inlet 3′, which forms a second air outlet Ao2 of the ventilation unit 200, through the inside air inlet module 208 and the MVHR system modules 202, 206, via the air supply fan module 207 to the outside air outlet module 205. The air supply inlet 3′ as depicted in the figures extends along the bottom surface of both the outside air outlet module 205 and the inside air outlet module 204, such that incoming air is distributed along a width of the floor prior to entering the floor space. The filter 216 is arranged in the air inlet piping Pi between the outside air inlet Ai and the MVHR system modules 202, 206, ensuring any dust, debris and other undesired contaminants are filtered from the incoming air prior to entering the MVHR system. The air supply fan 212 is arranged in between the air inlet piping Pi, such that rotation of the air supply fan 212 forces air from the outside air inlet Ai1 to the air supply inlet 3′.

[0096] The air outlet piping Po extends between an air outlet 2′, which forms a second air inlet A01 to the ventilation unit 200, and an outside air outlet Ao2, which forms the first air outlet of the ventilation unit 200. The air removal fan 214 is arranged in between the air outlet piping Po, such that rotation of the air removal fan 214 forces air from the air outlet 2′ to the outside air outlet Ao2. Prior to the air removal fan 214, the outlet piping is lead through the MVHR system 217, for recovering heat from the air passing through the outlet piping Po. The bypass 210 is provided onto the MVHR system 217, and provided in between sections of the inlet piping Pi prior to the positioning of the air supply fan 212. Via the bypass 210, incoming air through the inlet piping Pi is heated by the MVHR system 217 or, depending on a desired temperature inside the room compared to a temperature of the incoming air, lead around the MVHR system 217 to substantially maintain the outside air temperature.

[0097] Due to the arrangements of the air inlet and outlet piping and affiliated systems, the ventilation unit 200 is formed by two abutting columns of modules. One column is, in stacking order, formed by the outside air outlet module 204, the air removal fan module 203, one of the MVHR system and bypass modules 202 and the outside air inlet module 201. The other column is, in stacking order, formed by the inside air inlet module 208, the air supply fan module 207, the other of the MVHR system and bypass modules 206 and the inside air outlet module 205.

[0098] Each of the eight modules 201, 202, 203, 204, 205, 206, 207, 208 is equal in size and shape, having a length D1 equal to two times the width of a floor tile and a height H1 and width D2 equal to the width of a floor tile, such that the total length DT and total height HT of the ventilation unit are each four times the width of a floor tile. By ensuring the size of the modules matches the size of the floor tiles, the modules are easy to fit in between the tiles when placing the raised flooring around the modules.

[0099] The modules are made of a material which provides each module with sufficient stiffness and rigidity to allow the modules being stacked without affecting their shape, whilst being relatively light-weight, for ease of transport and installation. Hereto, the side surfaces of the modules may comprise sheets of a metallic material. However, preferably the side surfaces of the modules are made of wood, providing sound and vibrational insulation between the ventilation unit and the room in which it is placed.

[0100] Preferably, the floor tiles have a standard width and length of 60 cm (or about 24 inch), resulting in the ventilation unit 200 having both a total length DT and height HT of 240 cm (or about 96 inch). This height will fit into most rooms and allows the ventilation unit being integrated in the room design as a wall-section, either forming (part of) an external room wall or internal partitioning wall, depending on the particular size and use of the room.

[0101] In order to further reduce vibrations and noise from transferring between the flooring and the modules, dampers 50 are provided below the floor tiles directly abutting the ventilation unit 200, as shown in FIG. 6. These dampers are box-shaped elements, fitting between the supports 12, and are open on two opposite sides, for allowing air to flow through. The top of the dampers 50 may be provided with openings matching the openings in the floor tiles, but are preferably closed in order to provide optimal damping. Each of the box-shaped elements are preferably made of wood panels, and provided with one or more layers of foamed material on an inner surface thereof. These box-shaped elements are relatively easy and cheap to manufacture. However, it will be apparent to the skilled person that alternative materials, such as for example rubbers, and/or shapes, may be implemented to achieve a desired damping.

[0102] FIG. 10 shows a perspective view of a room 100′ which is used as an open plan office, and which is provided with a ventilation system according to the invention. Alternative to the room 100 shown in FIG. 1, the ventilation system shown in FIG. 10 comprises a partition wall 200′ masking a ventilation unit 200 as shown in FIGS. 6-9. The positioning of the partition wall 200′, and thus the ventilation unit, is chosen to fit with the floorplan of the workspace inside the office 100′. The permeable raised flooring 10′ and permeable lowered ceiling 1′ are laid around the partition wall 200′ and both have a hole pattern which depends on the distance from the partition wall 200′. In very large rooms, additional ventilation units may be included, with the hole pattern in both the raised flooring and the lowered ceiling being adjusted therefor. It will be apparent that the ventilation system in the room as depicted in FIG. 10 could be equally beneficially fitted in other rooms, including but not limited to classrooms, shops, gyms, nurseries and nursing homes.

[0103] In order to further enhance the distribution of air from the air inlet over the floor area, a diffuser may be provided in the floor space at the air supply 3′. FIG. 11 shows a cross-section of part of the floor space at the air supply 3′, with an example of such a diffuser 55. The diffuser 55 has a number of fins, which are placed at varying angles with respect to the air supply 3′, forming a fanned shape when seen from above. The fanned shape directs the incoming air flow into all directions of the floor space, aiding a more even distribution of air. The pattern of fins of the diffuser may be adjusted to a predetermined desired air distribution.

[0104] The present invention has been described above with reference to a number of exemplary embodiments as shown in the drawings. Modifications and alternative implementations of some parts or elements are possible, and are included in the scope of protection as defined in the added claims.