Patent Application
20180187904
Present invention relates to a device and a method for controlling a supply air flow at a type of chilled beam which may be termed cooling cassette, comfort module, comfort cassette or similar, which is used to provide supply air flow to a premises and control the room environment by cooling and/or heating. A chilled beam is often termed just as a chilled beam despite the fact that it nowadays also may comprise heating possibilities. The comfort cassette differs from the—since long known—chilled beam by that the supply air flow distribution out from the comfort cassette occurs in more than two directions, which is the normal for a chilled beam. The comfort cassette has often a so called four-way air distribution.
Within the field of air handling it is well known to use chilled beams to provide a premises with supply air and simultaneously control temperature and comfort in the premises by coordination of supply air and a circulation water flow through a integrated cooling-, cooling/heating coil. One problem with chilled beams delivering high cooling capacity is that they tend to be relatively elongated, thus occupying a large area/distance of the ceiling, where they normally are integrated. This to be able to deliver large cooling power and air flow within reasonable comfort demands. A more compact and space efficient variant has recently been developed and is basically a more compact chilled beam, but with four-way air distribution, which means that the air is distributed over a large ceiling area, yet the device is space efficient and space-saving. These units may be termed comfort module, climate cassette, cooling cassette or comfort cassette, and is manufactured in dimensions 600×600 mm and 600×1200 mm. Hereinafter in this application, the invention is termed comfort cassette and refers to a device which can be used for air supply and for cooling or for cooling and heating of the room air with one single device.
Developments in real estate operation constantly moves towards improving energy efficiency and in recent years the development of so-called VAV air treatment solutions has become increasingly important. More and more there are demands on that the ventilation of a premises is drawn down to a minimum during the time of non use of a premises, and then be able to switch over to normal operation at registered presence, and also provide the possibility to further force the air flow to maintain a good indoor climate. The few manufacturers on the market which today delivers VAV solutions to comfort cassettes have a solution where the VAV-function comprises a damper placed in the supply air stream before the comfort cassette or integrated on the inlet to the comfort cassette. Within the field of chilled beams the applicant earlier has presented and filed a patent application of a solution of a pressure independent chilled beam with VAV-control directly on the outlets of the so-called pressure box, which is presented in SE1450434-4. Advantages with this technique compared to competing solutions are discussed in that application and thus not comprehensively discussed here. Because the comfort cassettes directs the air in more than two directions, normally four, there is a problem or at least more time consuming to set all sides at set-up adjustment or, with today's solutions, impossible to apply a VAV-solution that not causes unwanted pressure drop, like an extra VAV-damper, in addition to the outlet pressure drop, and solutions adjusting the unit in all air distribution directions. There is thus a need of a comfort cassette with the ability to regulate the supply air in an energy-optimal way, and with the possibility of VAV control.
With the now present invention the object is achieved to solve the above problems in a first aspect of the invention, by a comfort cassette according to the preamble of claim 1, which is arranged to change the configuration at all groups of outlets, for supply air flow out from the comfort cassette pressure box, by only one movement of a cover member. In the preferred embodiment, the respective side/edge of the comfort cassette pressure box comprises one group of outlets, to let supply air flow stream in all directions where outlets are arranged, preferably perpendicular to the sides of the comfort cassette. Changing of the configuration of the groups means either that the number of outlets for outflow changes or that the outlet geometry as such changes regarding opening degree. The design of the cover member together with the outlet geometry, positioning and orientation enables that the movement of the cover member relative the outlets covers or opens the outlets, totally or partly, for through-flow of air, whereby the outflow of air from the comfort cassette is adjustable in all wanted directions where outlets are arranged. The outlets may for example be formed as elongated slots alternatively round holes, which are grouped so that a different number of outlets are open depending on the placement of the cover member. There are no solutions today, where a comfort cassette with outflow in more than two directions, can be controlled by only one movement, which allows control of all sides simultaneously and enables the use of cost-effective and energy-saving VAV-solution also at a comfort cassette.
According to a preferred embodiment of the invention the outlets are formed as elongated slots, which are orientated in a way that all slots have a longitudinal extent in the same direction as the direction of movement of the cover member. This means that a movement of the cover member for instance implies that all slots simultaneously begins to be covered, for example at a started closing movement, and all the slots thus are given the same opening degree around all edges/sides of comfort cassette. Thus, for example the slots may be oriented along two edges of the pressure box and perpendicular to the two other two edges of the pressure box, if it is preferred to have four-way air distribution. As previously mentioned, competitors' solutions not at all offer solutions with control directly on the outlets, but has other forms of throttlings, which is not positive given the total pressure drop and thus the energy costs over the entire operating time for comfort cassette.
According to another preferred embodiment the cover member is designed as a disc with portions close to the respective group of outlets, i.e. that parts of the disc will partly cover all outlets or completely cover some of the outlets in respective group, while a linear movement of the disc is performed. By moving the cover member/disc to different positions will thus supply airflow change at all groups of outlets simultaneously. It is thus an advantage over the known solutions that only one integral part regulates all sides of the comfort cassette at once, wherein the air flow in all directions changes by a movement of a cover member.
In a preferred embodiment of the comfort cassette is the respective opening degree of the outlets so designed that they are continuously adjustable between 0-100% in cooperation with the cover member displacement. This means that the flow can be fully adjusted to the needs of the premises that the comfort cassette serves, and moreover this fits well to a fully flexible VAV-solution, if there is a need for this. Known solutions have no ability to adjust the flow step-less in all directions, i.e. in addition to two directions and this through one single motion. With the present invention this is possible, which provides a quick adjustment of all sides and a possibility to have a completely VAV-controlled supply air flow.
Particularly preferred is that the outlets are arranged at four edges of the pressure box, that is, the comfort cassette is provided for four-way air distribution, which particularly at need of high cooling capacity is advantageous to achieve good comfort in the premises served. One problem with today's comfort cassettes is that they cannot be regulated entirely according to VAV-principle while the pressure drop still is the lowest possible. At best, it is possible to regulate maximum two sides and keep a basic flow at the other two sides, but if this basic flow should be, for example, a “non-presence” flow, this flow should be low, not to cost unnecessary energy when the room is not in use. Also the possibility of a high air flow in all four directions gets limited, because the flow in two directions thus is low, because this flow can't be VAV-regulated. With the invention it is possible to have a fully adjustable comfort cassette with four-way air distribution with low flow at “non presence”, but also with a high flow at high load in the premises, with high heating or cooling demand.
In a preferred embodiment of the invention is an actuator arranged at the comfort cassette, which actuator is arranged to cooperate with the cover member to provide the change of air flow in all directions. The movement of the cover member takes place as previously described in one direction, and this together with that the cover member is a single integral part makes it possible to, with only one actuator, change the configuration at all groups of outlets and thereby regulate the air flow in all directions. In this way, a cost-effective VAV-control is achieved for said type of comfort cassette, which previously was not possible. A certain position of the actuator movement corresponding to a certain position of the cover member relative to the outlets of the pressure box, representing a particular configuration of the outlets, such as the number of open outlets, the size of the outlets, or to various large outlets opening for the flow of supply air. The actuator position is therefore equivalent to a so-called k-factor of the outlets—the k-factor is a familiar conception in air conditioning. The actuator is arranged to change the configuration of the groups of outlets, preferably by a linear movement of the cover member, whereby, in the preferred embodiment, the open area of the outlets for outflow of supply air out of the pressure box changes. Preferably, the outlets are designed as elongated slots which, for example, are punched out of the pressure box close to its edges. Outside, on the surface of the pressure box is the cover member arranged in connection with the groups of outlets, and in the form of a disc, also provided with punched elongated slots. By that the actuator is linear and connected to the cover member, the cover member is moved linearly in relation to the outlets and covers more or less the outlets open area, in need of change of the supply airflow. By that the performance and flow characteristics of the comfort cassette is determined by laboratory tests according to standard test methods, the so-called k-factor is known for various opening areas of the outlets. The k-factor in this case is dynamic, that is, it changes according to a curve, because that the slot area is changed step-less. The linear movement of the actuator is preferably performed by a shaft, which is moved by the actuator outwardly or inwardly relative to the actuator, resulting in the linear movement. The position of the actuator shaft corresponds to a certain opening degree of the gaps which then corresponds to a k-factor.
According to a preferred embodiment of the invention the new comfort cassette is linked to the applicant's patent SE1450434-4 by that the pressure box comprises a pressure measuring socket, which is useful for representative control of static pressure in the pressure box. This pressure together with that the actuator position is recordable gives that the actual supply air in the comfort cassette is known, according to the description above concerning the k-factor and the actuator. Thus it is possible to calculate the actual air flow based on the actuator position (from which the k-factor is known) and the static pressure in the comfort cassette pressure box. No previously known comfort cassettes offer this facility and known solutions cannot present a fully flexible comfort cassette with VAV-control directly at the outlets without unnecessary pressure loss.
From a second aspect of the invention the object is achieved to solve the above mentioned problems by a method for controlling the supply air flow at a comfort cassette according to the preamble of claim 8, which method comprises that the supply air flow, and thus also the through induction generated circulation air flow, is changed in more than two directions, preferably four directions, by that a cover member is moved in only one direction. This is possible by that the outlets are arranged according to a configuration which is changeable by that the cover member is moved relative to the outlets and that all groups of outlets are changed simultaneously, by the movement of the cover member in the direction of movement. The outlets are arranged along more than two sides of the comfort cassette pressure box, which allows the supply airflow change at all sides where the outlets are provided, which has not previously been possible. In the preferred case the respective side/edge of the comfort cassette pressure box comprises a group of outlets, so that supply air can flow in all directions where outlets are arranged, preferably perpendicularly in relation to sides of the comfort cassette. Known solutions can only control the supply air by one cover member per group which changes the supply air to one side at a time, then only used when setting up the flow of the comfort cassette or if a need to change the air flow out of the comfort cassette occurs, due to change of use or for example draught problems in the premises. Alternatively, in some cases, the just mentioned manner for adjustment together with a volume control damper arranged before the comfort cassette or before the pressure box is used in the known solutions. With the now invented method all sides with outlets are regulated simultaneously, which provides a quick adjustment and the possibility of VAV-control in a cost effective and energy-wise good way.
In a preferred embodiment of the method of controlling the supply air flow at the comfort cassette, the cover member is moved by a linear movement, wherein the outlets entirely or partly are covered and thereby the supply air flow is changed. The linear motion is suitable both for outlets in the form of elongate slots, which then gradually gets covered/opened by the linear movement of the cover member, and also for outlets in the form of holes, of which some gets fully covered at different positions during movement of the cover member. The linear motion is well suited for precise control and for possible VAV-control, and a control of more than two sides by a linear movement of one cover member has not previously been possible in known solutions. Also preferred is that the movement of the cover member takes place step-less, and that the outlets are formed as elongated slots which are oriented in the same direction as the moving direction of the cover member, so that respective outlet opening degree is gradually adjustable between 0-100%. The supply flow rate is thus regulated exactly as required and can thus very accurately be adjusted, for example, at increased or decreased supply air need, increased or reduced need for cooling or heating, etc.
According to another preferred embodiment of the method an actuator cooperates with the cover member to make the change of the configuration of the outlets. The actuator is provided at the comfort cassette so that the actuator is connected to the cover member, and by the actuator movement the cover member is displaced to the desired position to provide a configuration of the groups of outlets corresponding to a desired supply air flow. Through collaboration between the cover member and actuator the supply airflow through all sides of the comfort cassette that include outlets will be adjustable, which can be used both when setting up the air flow, and also at VAV-control. The setting of a comfort cassette with a factory-mounted actuator could for example be done in a simple and time-efficient manner by sending a control signal to the actuator, in order to move the cover member to the correct position and adjust the air flow to be, for example, a basic flow through the comfort cassette. A very smooth method, useful to adjust and use the VAV-control at a comfort cassette with multi-way air distribution, is obtained, which gives full control of the supply air flow in all directions. This is not possible with known methods at a comfort cassette.
According to a preferred embodiment of the method the pressure box of the comfort cassette is provided with a pressure measuring socket, which is positioned so that a representative static pressure in the pressure box can be measured via the socket. This pressure is recorded either in a comprehensive control and monitoring system or directly into the actuator. The static pressure in the pressure box and the actuator position is recorded and on the basis of these the actual and correct supply air flow in the comfort cassette is calculated. Known methods at comfort cassettes do not offer this possibility and known solutions do not offer a way to record and calculate supply airflow at a fully flexible comfort cassette with VAV-control directly at the outlets, without excessive pressure drop through extra damper devices. When the comfort cassette comprises an actuator and a pressure measuring socket it is, according to a preferred embodiment of the method, possible that the comfort criteria of the premises, like for example carbon dioxide level, temperature etc. is registered, and at indicated need of a change of room climate, change the supply air flow through the comfort cassette. If the need indicates this the cover member moves by means of the actuator to in that way control the supply air flow through the comfort cassette, whereby the set-point for the premises eventually is achieved. By that all outlet directions at the comfort cassette are used may for instance larger cooling loads be provided to the room in a better way compared to a traditional cooling beam with only two outlet directions.
By the invention are a number of advantages over known solutions obtained:
Below schematic figures shows:
The structural design of the present invention are apparent in the following detailed description of an embodiment of the invention with reference to the accompanying drawings showing a preferred but not limiting embodiment of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1551192-6 | Sep 2015 | SE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/SE2016/050816 | 8/31/2016 | WO | 00 |
