A SYSTEM FOR SUPPLYING AIR TO A ROOM

Abstract

A system for supplying air under the ceiling of a room comprising a pair of air inlet openings arranged side by side and configured to supply a pair of air streams into the room along the ceiling. The pair of air inlet openings are controllable to assume a first configuration where the supplied pair of air streams have first air stream directions spanning a first span angle and form a first angle with the ceiling, and the pair of air streams are substantially distinct air streams; and a second configuration where the supplied pair of air streams have second air stream directions spanning a second span angle smaller than the first span angle and form a second angle with the ceiling and are directed lower than in the first configuration, and the pair of air streams combine to form a combined air stream.

Claims

1. A system for supplying air under the ceiling (21) of a room, the system comprising a pair of air inlet openings (10, 11) arranged side by side at a horizontal distance (d) from each other, each air inlet being configured to supply an air stream into the room in an air stream direction having a direction component parallel to the ceiling, wherein each inlet comprises a set of non-horizontal non-vertical tilted baffles controllable to assume a first configuration where the supplied pair of air streams have first air stream directions spanning a first span angle and form a first angle with the ceiling, and a second configuration where the supplied pair of air streams have second air stream directions spanning a second span angle and form a second angle with the ceiling, wherein the first span angle is different from the second span angle, and the first angle with the ceiling is different from the second angle with the ceiling.

2. A system according to claim 1 wherein, in the first configuration, the first air stream directions are divergent.

3. A system according to claim 1 wherein each of the first air stream directions has a direction component towards the ceiling.

4. A system according to claim 1 wherein, in the second configuration, the second air stream directions are non-divergent.

5. A system according to claim 1 wherein the second air stream directions do not have direction components towards the ceiling.

6. A method of operating a system according to claim 1, the method comprising at relatively high air flow, operating the system in the first configuration, and at relatively low air flow, operating the system in the second configuration.

7. A system according to claim 1, wherein in the first configuration the supplied pair of air streams are directed upwards and to the side to create two distinct jets.

8. A system according to claim 7, wherein the airstreams supplied in the first configuration are directed towards the ceiling in such a way that they spread out across the ceiling in a radial pattern, forming a radial wall jet.

9. A system according to claim 1, wherein in the second configuration the supplied pair of air streams are directed straight ahead and horizontally and are close enough to be attracted to each other to merge into a single, circular wall jet.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 shows a pair of wall mounted air inlet openings in a first configuration seen from above;

[0014] FIG. 2 shows the pair of air inlet openings in FIG. 1 seen from the side;

[0015] FIG. 3 shows the pair of air inlet openings in FIG. 1 in a second configuration and seen from above;

[0016] FIG. 4 shows the pair of air inlet openings in FIG. 3 seen from the side;

[0017] FIG. 5 shows the pair of air inlet openings in FIGS. 1 and 3 seen from the room;

[0018] FIG. 6 shows a set of air directing baffles for mounting in the air inlet openings in the first configuration and seen from the side; and

[0019] FIG. 7 shows the set of air directing baffles in FIG. 6 in the second configuration and seen from the side.

DETAILED DESCRIPTION OF THE INVENTION

[0020] In FIGS. 1, 3 and 5 are shown two inlet openings 10, 11 for supplying air mounted in a wall 20 of a room near the ceiling 21 and separated from each other by a horizontal distance d, e.g. by 2-3 times the largest horizontal dimension of the inlet openings. Alternatively, the inlet openings 10, 11 may arranged in a housing wall of a ventilation or air conditioning apparatus suspended from the ceiling or as a floor standing unit which does not require a wall of the room for being supported.

[0021] Each opening 10, 11 has a geometrical size that results in an essentially three-dimensional jet of the inlet air with e.g. a circular or oval cross section, as opposed to a mainly two-dimensional plane jet. The inlet openings 10, 11 are shown having a rectangular opening, but the openings may have any other suitable shape.

[0022] In FIGS. 5, 6 and 7 is shown that the inlet openings 10, 11 have a mechanical arrangement, here in the form of a set of adjustable baffles 12, for 10 changing the flow direction of air streams leaving the inlet openings. FIGS. 6 and 7 show the set of baffles 12 and an air stream directed onto the set of baffles. FIG. 6 show the baffles 12 in a first configuration or position where the baffles direct the air stream upwards, and in FIG. 7 the baffles 12 are in a second configuration or position where the baffles let the air stream pass through the set of baffles with substantially no change in direction. Other mechanical structures than baffles can be used to direct the inlet air streams, such as nozzles whose direction can be varied.

[0023] FIG. 5 shows the pair of air inlet openings 10, 11 with a set of baffles 12 in each inlet. In each inlet the set of baffles 12 is tilted so that the baffles are neither horizontal nor vertical.

[0024] In FIGS. 1, 2 and 6 the baffles 12 are in the first configuration, and the air streams leaving the two inlet openings 10, 11 thereby, in addition to a direction component parallel to the ceiling, also have a direction component directed towards the ceiling and thus forms a first angle with the ceiling. With the baffles 12 in the first configuration FIG. 1 also shows that the air streams leaving the two inlet openings 10, 11 also have a direction components directed away from each other, i.e. the air stream directions are diverging.

[0025] In FIGS. 3, 4 and 7 the baffles 12 are in the second configuration, and the air streams leaving the two inlet openings 10, 11 thereby have an air stream direction substantially parallel to the ceiling.

[0026] The positions of the baffles 12 are not limited to the first and second configurations shown here, but they can assume intermediate configurations and configurations beyond the interval defined by the above first and second configurations. The size and shape of the inlet openings can be different, and they can be controlled individually to obtain asymmetrical air flow conditions, if desired. The number of air inlet openings is not limited to two as shown here, but the ventilation apparatus can have three or more inlet openings according to need. The described change of direction of the air jets is intended to accompany a change in volume flow.

First Configuration, Maximum Flow

[0027] Jets are directed upwards and to the side to create two distinct jets which are essentially separate as illustrated in FIGS. 1, 2 and 6. This is accomplished as the combined result of having two inlet openings separated by a horizontal distance d, and by directing the jets away from each other to the sides. If the two jets are released with too small distance d between them and/or if they are released in parallel, or possibly converging, they will attract each other and merge with each other to form a single jet.

[0028] The two separated jets are directed towards the ceiling, which in turn cause them to spread out across the ceiling in a radial pattern, forming a radial wall jet or planar jet instead of a circular jet.

[0029] This broad air stream has a large contact surface to the surrounding room air, which consequently is effectively entrained into the inlet jet causing air velocities to drop due to larger volumes of air being set in motion.

[0030] The end result of the separated radial flows is that the throw is kept relatively short in spite of the large flow rate considered.

Second Configuration, Minimum Flow

[0031] Jets are directed e.g. straight ahead and horizontally as illustrated in FIGS. 3, 4 and 7. In this case, the two jets are close enough to be attracted to each other and will merge into a single, circular wall jet that in turn is attracted to the ceiling because of the Coanda effect. Compared to the first configuration with separated flows described above, there is less entrainment of room air, and the thus more concentrated flow keeps the throw relatively long.

[0032] At intermediate flow rates, the directions of the two jets can be varied to intermediate positions between those of the first and second configurations.

[0033] By choosing appropriate opening sizes corresponding to the volume flow, this principle ensures that the throw is kept nearly constant at a large variety of volume flows.

[0034] It is also possible to use the vacation of jet direction to prevent down draft in the case of large temperature difference between the inlet jets and room air. Cold inlet air has a tendency to drop because of density difference, thus creating an uncomfortable down-draft. By forming a more concentrated jet this can be prevented. This can be regulated automatically by measuring inlet temperature and room temperature as well as volume flow. However, care must be taken that velocities are not too high.