SE545839C2

SE545839C2 - Chilled beam

Info

Publication number: SE545839C2
Application number: SE2150586A
Authority: SE
Inventors: Peter Sønderskov; Torp Vegar Hagen
Original assignee: Trox Auranor Norge As
Priority date: 2018-10-31
Filing date: 2019-10-30
Publication date: 2024-02-20
Also published as: SE2150586A1; WO2020091603A1; NO20181398A1; NO345103B1

Abstract

SummaryChilled beam (11) for mounting in or under ceiling comprising a plenum box (14) for supplied air and an adjustable supplied air flap (17) in conjunction with the plenum box (14) and controlled by a first motor (15), further comprising a cooling loop (22) ) for circulating fluid on the underside of the chilled beam and a plurality of outlet nozzles (29) on the side walls of the chilled beam. The chilled beam further comprises a second motor (25) arranged to regulate the effective size of the outlet nozzles (29), where the second motor (25) is arranged to be controlled by a control unit (26) which receives signals from an airflow measurer (24) within the chilled beam, in such a way that the zone length and the degree of induction in the chilled beam maintain at the desired level regardless of the supplied air rate of the plenum box (14).

Description

Chilled beam The present application deals a chilled beam in accordance with the introduction part of patent claim Background In open-plan offices and industrial offices it is frequently need to renew air and control the temperature to maintain a comfortable, healthy and productive environment.

For this purpose, ventilation systems have been established for years with or without temperature control, but more and more often with such control, as the temperature on hot summer days can give temperatures and humidity not comfortable to stay in and where it is difficult performing productive work.

However, there can be various challenges with making such systems working well under varying conditions, since the need for fresh and supplied air can vary considerably and because the need for cooling can vary considerably.

So-called chilled beams have been extensively used for such purposes. These are coolers that both supply fresh air, that is conditioned, but also air that is already in the room, passing a cooling loop, so that an additional cooling effect is added, in addition to the fresh air being supplied.

In order that cooling effect is well distributed in the room, it is important that the speed the air leaves the cooler with is not too low, but spreads well under the ceiling before the air flows down. If this speed becomes too low, the cooling effect becomes too great right under the cooler and too small in the other areas of the room. An important parameter in this regard is the so-called zone length which is briefly explained as a measure of how far the air from the chilled beam moves before the speed falls below a given value, typically 0.15 m /s winter time and 0.2 m/ s summer time according to the Norwegian standard. If the zone length is too low, this is experienced as uncomfortable under the chilled beam. If the zone length is too high, you will instead experience air current down the walls or in the collision zone between two airjets.

Another parameter of importance is the induction rate, that is, the ratio between the volume flow rate of the air of the rom which is recycled via the chilled beam and the volume flow rate of the fresh supplied air (also referred to as supplied air) through the same. In some contexts, the induction rate is defined as the ratio of total volume flow rate (supplied air plus recirculated air) from the chilled beam to the volume flow rate of supplied air alone. Regardless which of the above definitions is used, the induction rate is a measure of how efficiently a given amount of supplied air is used.

Various measures have been proposed to ensure that the cooling air is well distributed both when the rate of supplied air is high and when it is low. EP 2 304 329 A4 describes an example of this type of equipment.

However, no existing systems have a satisfactory solution to the aforementioned problems.

Purpose of the invention Thus, it is purpose of the present application to provide a chilled beam which provides a satisfactory solution to the aforementioned problems, when there is a need for low volume rate of supplied air (also called supplied air rate) as well as high volume rate of supplied air.

Present application The above-mentioned purpose is achieved through the chilled beam of the present application as defined in patent claim Preferred embodiments of the invention are set forth in the dependent patent claims. The chilled beam according to the present application, ensures that the zone length and the degree of induction in the chilled beam maintains at the desired level, regardless of whether the supplied air rate is high or low. The velocity of the air flow from the chilled beam maintains, so that no local fall of cold air under the chilled beam occurs when operating at low supplied air rates.

For example, maintaining the zone length and induction degree of the chilled beam can mean that the pressure is kept constant, or it can also alternatively mean that the pressure within a predefined interval is allowed to be reduced or increased as the rate is reduced or increased. The point is that with the extra motor, flap control connected to it, and a logical control of the effective area of the outlet nozzles, you are completely free to choose pressure within the chilled beam's plenum box regardless of the volume rate in to this (plenum box).

Detailed description of the embodiments according to the invention In the following, the invention is further explained in the form of non-limiting embodiments illustrated in the accompanying figures.

Figure 1 is a perspective view of a chilled beam according to the present application. Figure 2 is an end section of a chilled beam according to the present application. Figure 3 is a sketch showing a partial side section of an embodiment of the present application, but also illustrating a logical control system according to the invention. Figure 4 shows a side view of an embodiment of the present application.

Figures 5a-d show an enlarged side view of a detail of the chilled beam according to the present application.

Figure 6 shows in perspective a chilled beam according to the present application mounted under a ceiling.

Figure 7 shows in perspective a chilled beam according to present application mounted in a ceiling.

Figure 1 shows a chilled beam 11 with an outer body 12, an in|et 13 to a plenum box 14 (shown in dotted line). The figure shows a first motor 15 for controlling a supplied air flap (not shown) and an underside 16 which has a grid structure so that air can passes through. The general construction of the chilled beam shown in figure 1 is also designed in accordance with prior art in the field.

Figure 2 shows an end section of the chilled beam shown in figure 1. Here, the body 12 and the plenum box 14 and an in|et 21a and an outlet 21b for cooling liquid and a cooling loop 22 are shown between the in|et 21a and the outlet 21b. The cooling loop 22 typically has the form of straight, parallel pipe sections connected to u-shaped sections (not shown). The pipe sections are typically provided with cooling flanges 23 to increase their effective area and thereby their ability to transfer heat.

The arrows marked A show how the supplied air of the plenum box 14 passes out through nozzles in this, to both sides and obliquely to the side edges of the chilled beam throughout its length. The movement in the air caused in the room, causes air to be taken up towards the central part of the chilled beam and up past the cooling loop as shown with arrows B, and thereby cooled, before this cooled air of the room is mixed with the air from the nozzles out of the plenum box. This mixed air, shown with arrows C, then leaves the chilled beam in a direction mainly horizontal along the ceiling. The cold air will fall down due to greater density than warmer air, but since it leaves the chilled beam with a horizontal speed component, it will be well distributed in the room and not cool excessively directly under the chilled beam.

An airflow measurer 24 is shown in the in|et 13. The airflow measurer 24, typically a venturi or a hot wire anemometer, is connected to a control unit 26, typically a (programmable logic control).

Figure 3 shows a side view of the upper part of the chilled beam, meaning the part which mainly encloses the plenum box 14. On the left side is shown the in|et 13 thereto and the first motor 15 which controls a supplied air flap 17. In case of a great need for cooling the flap is fully open so that the maximum volume rate of conditioned air enters the plenum box 14 and further into the room therefrom. As figure 3 shows, the first motor 15 is in logical connection with the control unit 26 such that information from this determines the position of the supplied air flap 17. A substantial new element is shown below. To the right of figure 3 is shown a second motor 25 which is also in contact with the control unit 26 which in turn is in logical contact with an air flow measurer 24 in the in|et 13. The second motor 25 is arranged so that it can change the effective cross- sectional area of the outlet nozzles and thereby the volume rate of air emitting through these. This affects the flow conditions through the plenum box and thereby the volume rate recorded by the airflow measurer 24. The control unit 26 can thereby be tuned (programmed) so that the first and second motors cooperate to provide a desired relation between the effective area of the supplied air flap and the effective area of the sum of outlet nozzles. More specifically, the control unit may be programmed to maintain a desired velocity of air out through the outlet nozzles. Typically, this may mean that the second motor at all times controls the effective size of the outlet nozzles so that the desired amount of air determined by the control unit 26 at all times passes through the plenum box.

Figure 3 further shows a unit 27 which can be a thermostat which provides the control unit 26 with information on the temperature in the room and thereby about the need for changing the volume rate of supplied air, which is then regulated with the first motor 15. Figure 3 also shows a unit 28 for the basic setting of the unit, a setting which may vary depending on the room temperature desired, the size of the room and other basic requirements for the operation of the unit. This allows individual adjustment of the individual chilled beam without need to reprogram the control unit 26. For example, there may be a need for a different setting in rooms facing south compared to rooms facing east or north.

Figure 4 shows a slightly enlarged side view of the chilled beam without the body 12, with plenum box 14 at the top and cooling loop 18 at the bottom. Also shown here, a number of outlet nozzles 29 along the lower part of the plenum box 14. Furthermore, a rod-shaped type of flap 30 is guided along a linear forward and reverse movement of the second motor 25. The rod-shaped flap 30 has the same number of openings as there are outlet nozzles and with the same spacing. Upon gradual movement of the flap 30, the outlet nozzles change from being fully open to becoming gradually more closed until an at least possible opening.

Figure 5a shows a section of the wall of the chilled beam plenum box with a plurality of six outlet nozzles 29. Below is shown the flap 30 - in non-assembled condition - which is adapted to be operated by the second motor 25. The flap has six windows 31 which are located at the same mutual distance as the distance between the outlet nozzles.

In Fig. 5b it is shown the flap mounted behind (within) the outlet nozzles 29 in the "neutral" position, that is, with fully open nozzles. In Figure 5c the flap 30 is slightly moved to the left and here the windows 30 do not fully overlap the outlet nozzles which have therefore reduced their effective size with an area shown shaded. In Figure 5d the flap 30 is moved further to the left and the effective opening of the outlet nozzles is further reduced here. Since the response to the airflow volume rate through the nozzles is not proportional to the nozzle area, it may be appropriate to use nozzle openings which are not of regular shape but are tapered.

Figure 6 shows a chilled beam according to the present application mounted under an inner-roof or a ceiling.

Figure 7 shows a chilled beam according to the present application mounted integrated in a ceiling. In this assembly, both air and cooling water can be directed invisibly to the chilled beam.

What is genuinely new is not that the effective area of the outlet nozzles can be regulated, but that this regulation is set in a system by means of airflow measurement and logic control which allows a predetermined change in the effective size of the outlet nozzles in response to a change in the effective opening of the inlet flap.

Claims

Patent claims

1. Chilled beam (11) for mounting in or under ceiling comprising: - a plenum box (14) for supplied air, with an inlet (13) to the plenum box (14), - an adjustable supplied air flap (17) in conjunction with the plenum box (14) and controlled by a first motor (15), - a cooling loop (18, 22) for circulating fluid on the underside of the chilled beam, where room air is induced through the cooling loop (18, 22), and - a plurality of outlet nozzles (29) on the side walls of the chilled beam for the supply of air out of the plenum box (14), characterized in that the chilled beam comprises a second motor (25) arranged to regulate the effective size of the outlet nozzles (29) and that the second motor (25) is arranged to be controlled by a control unit (26) which receives signals from an airflow measurer (24) in the plenum box inlet (13), in such a way that the zone length and the degree of induction in the chilled beam are maintain§g:ï_ at the desired level regardless of the supplied air rate of the plenum box (14).

2. Chilled beam according to claim 1, where the second motor (25) is controlled by the control unit (26) in such a way that a narrowing of the supplied air flap (17) results in a reduction of the effective size of the outlet nozzles (29).

3. Chilled beam according to claim 1 or claim 2, where the second motor (25) is control- led by the control unit (26) in such a way that the pressure maintains at a constant level.

4. Chilled beam according to any one of the preceding claims, where the second motor (25) controlls the effective size of the outlet nozzles (29) with a rod-shaped flap (30) on the respective sides of the chilled beam, where the flap (30) has one opening (31) for each of the outlet nozzles.

5. Chilled beam according to any one of the preceding claims, where also the first motor (15) is controlled by the control unit (26).

6. Chilled beam according to any one of the preceding claims, where the control unit (26) is a programmable logic control (PLC).

7. Chilled beam according to any one of the preceding claims, where the second motor (25) is a linear motor.