GB2523000A

GB2523000A - Ventilation arrangement

Info

Publication number: GB2523000A
Application number: GB1423085.8A
Authority: GB
Inventors: Shaun Fitzgerald
Original assignee: BREATHING BUILDINGS Ltd
Current assignee: BREATHING BUILDINGS Ltd
Priority date: 2013-12-23
Filing date: 2014-12-23
Publication date: 2015-08-12
Also published as: GB201322916D0

Abstract

A ventilation arrangement with a partition 104 between a natural ventilation exhaust chamber 102 having the outflowing air pathway 15 to the ambient arranged at right angles to the incoming air pathway 105a from a room in a building, and a mixing chamber for mixing exterior air 110 and interior air 105b, the mixing chamber having at least one ninety or more degrees turn for the air by means of forced flow produced e.g. by a fan, and from which mixed air is delivered to a room. The two vents being fed with air from the room interior may be formed like grilles, fixed or adjustable. The apertures communicating with the ambient are preferably closable, the air flow passing therethrough being adjustable via one or more damper blades (200, fig. 4). The exhaust chamber may be divided in two or more chambers, one of them having a constriction in the form of a step or shelf. A duct (4, fig. 5) may be fitted to the mixing chamber to deliver air to a room via its open distal end (7, fig. 5) and one or more intermediate outlets (6, fig. 5).

Description

Ventilation Arrangement This invention relates generally to ventilation arrangements and more particularly such arrangements used in building spaces such as school rooms to utilise natural ventilation.

Large rooms and circulation spaces in buildings such as schools tend to have exterior walls but can often have limited or no access to roof space for stack based natural ventilation systems. Ventilation is required to maintain air quality during the occupied time and to assist with cooling by removal of the heat build-up arising from IT loads, lighting, people and solar gains. In winter the temperature of the incoming air is low and causes cold draughts in the vicinity of the air supply openings. In summer, higher rates of ventilation are desirable to provide cooling to the space but temperatures will be hotter away from the supply vents. Differentiations in temperature will be exacerbated by higher occupation levels and/or machines such as photocopiers and computers which may emit heat. By maximising natural air flows in summer and enhancing air movement within the space significant benefits can be made in terms of reducing the amount of heat input during cooler weather which would otherwise be used to pre-heat supply air, and reducing the amount of air conditioning required in hotter weather during the day when the room or space is occupied.

Conventional ventilation systems tend to add heat to incoming air in winter. This can cause overheating in the interior of the space away from the inlet vent due to the presence of internal heat gains. This in turn leads to higher ventilation flow rates and thence more heat being supplied resulting in excessive heating bills. Furthermore, natural ventilation systems which just use a single external façade for air supply and extraction tend to lead to overheating when the space is deeper than approximately 2.5 times the floor to ceiling height.

In accordance with aspects of the present invention there is provided a ventilation arrangement comprising a mixing compartment for interior air and exterior air comprising a front section with variable control aperture having a divider between a natural ventilation exhaust chamber to one side, comprising an air pathway from the room to the exhaust chamber and an air pathway from the exhaust chamber to the exterior substantially perpendicular to the air pathway between the room and exhaust chamber, and a mixing chamber to the other side of the front section with an exterior air inlet and an interior air inlet, the mixing chamber having at least one 90 or more degrees turn for the air by means of forced flow and from which mixed air is delivered to an exhaust vent for supply of mixed air to the room either directly from the unit or via a conduit attached to the ventilation arrangement.

The room air inflow vent to the mixing chamber and the room air inlet to the exhaust chamber may be formed with a fixed or variable grille to allow the available open cross-sectional area to be varied. The exterior air inlet and outlet from the exhaust chamber may be associated with a damper blade to vary the available cross-sectional area for air flow.

The means for forced air flow may be a fan driven mechanically such as with an electric motor.

The exterior air inlet and outlet from the exhaust apertures are closable.

The exhaust chamber may be divided with one of the chambers including a step or shelf constriction. The constriction may vary with distance from the outlet aperture.

In accordance with some further aspects of the present invention there may be provided a ventilation arrangement comprising a conduit with an air mixer compartment as described above at one end and a single outlet or series of outlets to the room. A fan can be located within the conduit.

The conduit may be insulated. The insulation may be thermal and/or acoustic.

A distal end of the conduit away from the mixer compartment may be open. The distal end may have a greater or less cross-sectional area than the conduit. The conduit may have a consistent cross-sectional area. The cross-sectional area of the conduit and/or the distal end may be variable. The cross-sectional area of the conduit and/or the distal end may be variable by an actuator.

The cross-sectional area of each outlet vent from the conduit may be variable as required. The cross-sectional area may be fixed in use. The cross-sectional area may be variably set in use. The cross-sectional area may be variably adjustable in use. The interior air inlet to the mixing chamber may be wholly or partially closed by a closure or shutter.

Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a schematic front and underside perspective view of a ventilation arrangement in a building space in accordance with some aspects of the present invention; Figure 2 is a schematic back and underside perspective view of the ventilation arrangement as depicted in Figure 1; Figure 3 is a schematic perspective view of the ventilation arrangement with a cowl; Figure 4 is a front view of a ventilation arrangement; and, Figure 5 is a side view of a ventilation system using a ventilation arrangement.

As indicated above, spaces and rooms in buildings need to be ventilated. Natural ventilation has inherent advantages over mechanical ventilation in terms of less energy usage and effectiveness but what is also important is that if any fan driven flow is needed anywhere in the room that the energy for such flow is limited to that necessary. Natural ventilation uses buoyancy forces to a large extent to drive flow and to provide mixing of warmer and cooler air streams and zones to best advantage. In a room which does not have easy access to a roof and the opportunity to include vertical atria or chimneys or the like it may be difficult to fully or substantially depend upon buoyancy forces and natural entrainment to provide appropriate mixing and distribution of air within the room.

In accordance with aspects of the present invention a conduit can be provided which can be vertical or inclined but is normally lateral or horizontal to provide a means to distribute air flows in a space or room. At one end of the conduit a mixing compartment is provided which can receive external air through a front vent section. Typically the front vent section extends through an exterior wall or over a window with the interior air inlet to the mixing chamber adjacent or close to that wall or window. The conduit extends into the room or space and may incorporate one or more outlet vents between the mixing compartment and a distal end of the conduit which is open. Depending upon the shuttering, external damper position and/or mechanical flow drive the relative proportions of external air and internal air in the mixing compartment and thence delivered to the room can be adjusted. In such circumstances the mixed external and room air is pushed out of the ventilation system into the room or passes along the conduit before being delivered to the room through the distal end and any intermediate outlet vents. On a summer's day when the extemal air is cooler than the internal air but warm enough to be introduced without causing cold draughts, the mixing in the compartment will be set accordingly to minimum. On a winter's day the external air will be too cold to be delivered directly into the space and so the degree of mixing will be increased. The ideal is to provide more desirable air conditions in terms of ventilation without need for excessive heating of fresh external air in winter or cooling in summer.

Figure 3 illustrates a mixing compartment 5 in accordance with aspects of the present invention which can be used in a ventilation arrangement with a conduit and other elements to ventilate a room or space. The component 5 has a sleeve 100 to allow a conduit to be secured and vents 101 for air flows into the compartment 5 and with flows through a front section 99 comprising a natural outflow chamber 102 and a fresh air inlet 103 to the mixing chamber divided by a divider 104. The arrows 105 show in flows from a room with flow 105a into the natural outflow chamber 102 through an inflow vent 106 and flow 105b through an interior air inlet 107 to the mixing chamber. By the nature of hotter air rising the flow 105a will naturally exhaust through outflow vent 108 which is generally substantially perpendicular to the inlet 106 so the air flow lOSa turns before being exhausted through the vent 108.

The compartment 5 will be associated with an external wall or over a window so a front edge 99 extends through that wall or window facia to the exterior with or without a Louvre to provide the necessary rain protection across the wall or window.

The interior air flow 105b entering through inlet 107 and exterior air inflow 110 entering through an exterior air inlet 109 are mixed in mixing compartment 5 before being turned by at least 90 degrees leading to the exit aperture 100. Such turning provides some resistance to flow so that adjustable grilles can be used to allow controlled release of the flow. It will also be appreciated that such turning of air flow will reduce draught and flow noise as perceived in the building and allow control of air returning to the room.

Figure 4 illustrates the front of the compartment 5 in which a damper blade 200 acts across the vents 102, 103 as exhausts or inlets for air flows in accordance with aspects of the present invention. The damper blade 200 allows control of in and out flows of air by altering the available open cross-sectional areas to such flows. It will be appreciated that there may be a single blade 200 as depicted or separate blades for each vent or opening 102, 103 with an actuator 201 to one side to set the damper blade 200 as required. This adjustment by the actuator may be manual or automatic dependent upon temperature or wind direction. The actuator may also be remotely controlled by a controller (not shown) independently or in concert with other elements in a building environmental control regime.

As depicted in figure 3 it will be appreciated that grilles 101 also control mixed air flows and will be located upon a lower underside 202 of the compartment 5. As will be described later these grilles can be open or closed or partially open to allow variation to mixed air flows returned to the room.

In terms of construction the compartment Swill be formed of sheet metal or a plastic material with insulation (thermal and/or acoustic) applied or formed within the interior walls.

Generally the compartment 5 will have a length 302 in the order of 1000 millimetres whilst the cowl 300 shall have a length of typically 200 to 500 millimetres to allow projection through a wall or over a window. Such dimensions provide sufficient depths to allow mixing and return of mixed air to a room or space.

Figure 1 illustrates a mixing compartment 5 in a winter mixing condition and Figure 2 illustrates a mixing compartment 5 in a summer boost condition. In figure 2 it will be noted that the grilles 107 are configured so that they are preferably closed. The parts of the grille which are closed mean there is less air recirculation.

The conduit 4 extends away from the ventilation arrangement 5 inwards into the room 2 in a desired configuration. Typically the conduit 4 extends towards an interior wall 9.

There may be multiple ventilation arrangements in a given room 2. The conduit 4 is generally a tube or pipe of an appropriate cross-sectional area which may be fixed along its length or vary for operational performance or by necessity due to constrictions/obstructions in the building structure 3 but then compensated in the configuration of the arrangement. As shown the conduit 4 is generally lateral but may be inclined or vertical at least in part if required but then the differing buoyancy and thermal stratification effects must be accounted for in the configuration of the arrangement design in accordance with aspects of the invention. Thus, the conduit 4 may be rendered with a greater cross-section or different aspect ratio between height and width or have a different shape so rather than circular the conduit 4 could be oval or rectangular in cross-section to control air flow in the conduit in association with the main drivers for air flow aspects of the present invention as described later.

The mixing compartment 5 as indicated is located in a facia of a window 8 or a wall.

The compartment 5 is generally a box with horizontal or vertical openings for inflow and exhaust outflow. The vertical vent opening 109 draws in external air or expels internal air in the room 2 from or to the exterior of the building 3. The internal air and the external air are mixed in the compartment in proportion to the shuttering of the vents and/or natural and mechanical flow drivers such as a motor driven fan and convection. The vents or grilles will normally be Louvre type arrangements or have dampers to alter the available cross-sectional area of the vent and so the capacity for air flows into or out of the compartment for mixing. Such changes in available cross-sectional area 99 and 107 can be significantly effective with natural up flow 105b into the mixing chamber due to convection. However, advantageously the present invention also includes a means to mechanically drive unmixed fresh air flow using a fan with 107 preferably closed. The fan may be located at a displaced location within the conduit 4 or a respective fan within 5. The fan or fans can be operated at different speeds so creating different flow rates through the vents in the compartment 5. By mixing external air and internal air it will be appreciated a desired air quality such as temperature can be attained and retained without too much further energy input through central heating radiators or air conditioning. The present invention provides a capacity for external air in flows through the external vent 99 and a capacity for air flows in and out through the vents 101, out through the vent formed by 100 and the intermediate vents 6 and the distal end 7 when a conduit 4 is used. The air mixed in the compartment 5 can effectively determine the air presented by the present ventilation arrangement in the room 2.

The intermediate vent 6 or several such vents are located along the length of the conduit 4 as shown. The intermediate vent 6 is generally up facing towards the ceiling of the room 2 or sideways. In such a configuration as will be appreciated the natural thermal downward air flow from cooler supply air into the room 2 can be utilised. Damper 200 will be used to provide full or partial closures to control air flow but additionally mechanically driven flow by a fan can be used in the ventilation arrangement 5 or conduit 4. Thus, in such circumstances natural air flow can be used and only supplemented with mechanically driven flow when required or where acquisition of a desired air temperature more quickly is desired.

The distal end 7 is normally fully open and spaced from the interior wall 9 so that air can flow out as required. In such circumstances air can be expelled as part of the mix of air created at the mixing compartment 5. The end 7 may be simply an opening to the conduit 4 or may include some form of fixed or variable constriction which can be set for particular room 2 conditions or variable in operation using an actuator. The actuator in addition to any actuators and controllers for the other vents and fans can all be coordinated by a master controller to set the vents and speed(s) of the fan(s) for prevailing conditions within the building at that time or changes of usage e.g. a foldable partition wall is removed or number of occupants changes or nature of occupation.

As indicated above aspects of the present invention have particular use in relation to large rooms and spaces such as in schools and public buildings where occupation levels vary and there can be significant differences in air temperature. The present ventilation arrangement can be located in flat roof buildings and for example only a room 2 with a height of 2.7 metres and a depth 11 of 6.8 metres away from a window 8 can accommodate a mixing compartment 5 with a 0.3 metres square lateral opening 99 and vent 101. The conduit 4 as seen in figure 5 extends substantially adjacent a ceiling or soffit 14 towards the interior wall 9. In such circumstances a ventilation arrangement is provided which will achieve desired air temperature control and ventilation whilst only impinging 0.3 metres into the room 2 so that with a 2.7 metres high room an adequate height of about 2.4 metres (2.7 minus 0.3 metres) is left for normal operations.

As seen in figure 1 air flows shown by arrowheads 15, 16 can be provided at different depthsllocations into and out of the room 2 and each of these flows will be at different rates dependent upon the flow stimulus provided by fans and natural flow with an objective of achieving a more even or desired temperature disposition which may be even or not within the room 2 using a mix of external fresh air and internal air taken from the room 2 into the compartment 5 for mixing. Mixing with existing internal air will mean that less conditioning for warming of the external air is required when drawn into the ventilation system.

Claims

Claims 1. A ventilation arrangement comprising a mixing compartment for interior air and exterior air comprising a front section with variable control aperture having a divider between a natural ventilation exhaust chamber to one side, comprising an air pathway from the room to the exhaust chamber and an air pathway from the exhaust chamber to the exterior substantially perpendicular to the air pathway between the room and exhaust chamber, and a mixing chamber to the other side of the front section with an exterior air inlet and an interior air inlet, the mixing chamber having at least one 90 or more degrees turn for the air by means of forced flow and from which mixed air is delivered to an exhaust vent for supply of mixed air to the room either directly from the unit or via a conduit attached to the ventilation arrangement.
2. An arrangement as claimed in claim 1 wherein the room air inflow vent to the mixing chamber and the room air inlet to the exhaust chamber are formed with a fixed or variable grille to allow the available open cross-sectional area to be varied.
3. An arrangement as claimed in claim 1 or claim 2 wherein the exterior air inlet and outlet from the exhaust chamber are associated with a damper blade to vary the available cross-sectional area for air flow.
4. An arrangement as claimed in any of claims 1 to 3 wherein the means for forced air flow is a fan driven mechanically by an electric motor.
5. An arrangement as claimed in any preceding claim wherein the exterior air inlet and the outlet from the exhaust apertures have means to allow them to be closable.
6. An arrangement as claimed in any preceding claim wherein the exhaust chamber is divided into more than one chamber with one of the chambers including a step or shelf constriction.
7. An arrangement as claimed in claim 6 wherein the constriction has means to allow it to vary in terms of the extent of constriction with distance from the outlet aperture.
8. A ventilation arrangement as claimed in any preceding claims comprising a conduit with the mixer compartment at one end and a single outlet or series of outlets to a room.
9. An arrangement as claimed in claim 8 wherein a fan is located within the conduit.
10. An arrangement as claimed in claim 8 or claim 9 wherein the conduit is insulated.
11. An arrangement as claimed in claim 10 wherein the insulation is thermal and/or acoustic.
12. An arrangement as claimed in any of claims 8 to 11 wherein a distal end of the conduit away from the mixer compartment is open.
13. An arrangement as claimed in claim 12 wherein the distal end has a greater or less cross-sectional area than the conduit.
14. An arrangement as claimed in claim 12 or claim 13 wherein the conduit has a consistent cross-sectional area.
15. An arrangement as claimed in claim 12 or claim 13 wherein the cross-sectional area of the conduit and/or the distal end is variable.
16. An arrangement as claimed in claim 15 wherein the cross-sectional area of the conduit and/or the distal end are variable by means of an actuator.
17. An arrangement as claimed in any preceding claim wherein the cross-sectional area of each outlet vent from the conduit is variable as required by an adjustable flap.
18. An arrangement as claimed in claim 17 wherein the cross-sectional area is fixed in use.
19. An arrangement as claimed in claim 17 wherein the cross-sectional area is variably set in use dependent upon conditions.
20. An arrangement as claimed in any preceding claim wherein the interior air inlet to the mixing chamber is wholly or partially closed by a closure or shutter.
21. A ventilation arrangement substantially as hereinbefore described with reference to the accompanying drawings.