EP3832218B1 - Control unit for opening and closing windows and building comprising such a control unit - Google Patents

Description

technical field

The present invention relates to a building according to the preamble of claim 1.

State of the art

According to the current state of the art, it is known that the temperature, wind, rain and humidity can be measured as actuating signals for a control unit which controls the opening and closing of windows. The desired internal temperature is usually used as the control variable.

CN 107575119A describes a control that enables windows to be opened and closed depending on the volume, humidity and wind speed, so that on the one hand the window is closed when there is heavy rain or strong wind or loud noise, so that no damage occurs and undisturbed sleep is possible, and on the other hand the window is/remains open when there are no adverse effects from the environment.

EP 1225399 A1 describes the equipment of each window with its own measuring unit to determine the local weather conditions. The weather conditions can be used to decide whether or not to ventilate, for example depending on whether opening a window causes local damage or not.

EP 3457041 A1 describes a system for ventilating a building, in which the opening of one damper is controlled as a function of another damper. Temperatures from different rooms can also be taken into account.

However, this procedure does not take into account that a certain air exchange is desired in rooms even under adverse environmental conditions. Air exchange describes how often the entire air in a room was exchanged per unit of time, usually one hour. Although possible CN 107575119A The fact that the air exchange can take place under good environmental conditions does not control the extent of the air exchange.

A building with a control unit according to the preamble of claim 1 is off WO 00/39506 A known. A school is mentioned in this document (last paragraph on page 13), but one or more control units 33 are provided in several separate rooms (as is always the case in schools). This means that each room can be ventilated individually.

In large buildings (such as schools) there is usually a central aisle with classrooms on either side of the aisle. Thus, each classroom only has the windows on one side of the room; on the opposite side is the door to the corridor, as shown in the attached 1 is shown.

Normally, the individual rooms are not fluidly connected (unless the doors to the corridor are left open), and the WO 00/39506 A is no exception here. The problem with such an arrangement is that you can hardly ventilate sufficiently without creating annoying drafts: because if the air is to flow from the window to the opposite side of the room (the necessary air exchange should also take place there), you have to close the window relatively open wide, and then again and again there are strong, disturbing drafts near the windows.

There are investigations into how strong the air exchange in such a room arrangement depends on the opening angle of the windows, the temperature difference between the indoor air and the outside air, the wind, etc., with the result that the air exchange is very difficult to predict.

This is also visually plausible. Suppose the front and rear windows are open in a classroom. If the wind is directed relatively exactly at right angles to the facade, only the pressure in the classroom will increase (dynamic pressure), but almost no air flow will be caused. If the wind direction changes (even just a little) so that the wind comes (at least a little) from behind, then the classroom becomes relative rapidly build up airflow from back to front ("it pulls"). Technically, this is almost impossible to control.

The results are best reproducible if you open two tilting windows arranged one above the other on cold days, because then the air (even without wind) flows in through the bottom tilting window and out through the top tilting window (chimney effect). However, this has the disadvantage that the schoolchildren sitting in front of the open bottom tilting window are directly exposed to the cold outside air, which is unacceptable.

Brief description of the invention

The aim of the invention is to provide a building with a control unit that provides a required air exchange by means of natural convection in a well reproducible manner.

According to the invention, this is achieved by a building with a control unit having the features of claim 1.

According to the invention, the rooms are fluidically connected to one another in such a way that, when the windows are open, air can be transported from one side of the building to the opposite side of the building (possibly also to another side of the building). Namely, it was found within the scope of the present invention that the pressure difference between opposite sides of a building can be determined relatively accurately on the basis of wind speed and wind direction, and this pressure difference also changes only slightly if the wind speed or wind direction changes slightly.

This pressure difference in turn has a very reproducible effect on the air exchange (i.e. the speed of the air flow in the building). With relatively little control effort, the windows can thus be controlled in such a way that the desired air exchange is achieved without risking draughts.

The proposed measures thus make it possible to achieve a constant exchange of air by varying the opening angle to reach. This enables a pleasant room and learning climate, especially in schools, but also in other buildings.

An accurate measurement of the differential pressure between two sides of a building is relatively complex. Therefore, according to one embodiment of the invention, it is provided that the control unit receives the wind direction and the wind speed as input variables and uses them to determine the differential pressure between the two sides of the building.

With today's simulation methods, it is relatively easy to calculate the differential pressure between two sides of a building depending on the wind direction and wind speed. This calculation only needs to be carried out once for a few wind directions and wind speeds and the result stored in the control unit; if intermediate values occur, the control unit can interpolate between the stored values or simply take the closest value. To measure the wind direction and wind speed, only a measuring device is required outside the building in the form of a rotation anemometer or an ultrasonic anemometer.

If the measuring device for determining the wind direction and the wind speed is provided at a minimum distance of 10 m, preferably 20 m, from the building, there is the additional advantage that gusts of wind can be detected before they hit the building. This means that the windows can be closed further before the pressure difference in the building increases and drafts occur. Conversely, if the measuring device used to determine the wind direction and wind speed detects a drop in the wind, you will have to wait a few seconds before opening the window further, because the outside pressure at the window also drops with a time lag.

In such a building, which is regulated by such a control unit, it is expedient if a radiator is provided under at least one window, with a grille with a skirt provided above the radiator but below the window as a resistance to reducing the flow of warm air in front of the window is. In winter, the radiator prevents the cold air flowing in through the window Air sinks downwards, which would be uncomfortable for people sitting near the window. On the other hand, the grille with apron prevents an excessive heat curtain from forming in front of the window, which would reduce the desired air exchange.

Brief description of the drawing figures

The invention is explained in more detail on the basis of the following exemplary embodiment. 1 Figure 1 shows the floor plan of a highly simplified building to which the present invention can be applied; and 2 shows a tilting window with an arrangement to keep unpleasant cold air inside to avoid winter.

Description of execution types

The building 11 consists of only two rooms 12, 13, between which a corridor 14 is located. The corridor 14 can be entered via an entrance door 41; from corridor 14 you can reach rooms 12 and 13 via doors 42 and 43 respectively. The doors 41, 42 and 43 are normally closed so that they do not affect the air exchange.

Both the space 12 and the space 13 are fluidically connected to the corridor 14 through overflow openings 42 and 43, respectively. These overflow openings 42 and 43 are preferably provided in a suspended ceiling; however, all other known overflow openings can also be used. In the rooms 12 and 13 narrow windows 22 and 32 or 23 and 33 are provided, the opening angle of which can be adjusted by the control device according to the invention. Of course, further windows (in particular for sufficient daylight) can be provided.

The present invention is intended in particular for schools where classrooms are provided on both sides of a corridor.

The following example should clarify the calculation.

Determining how large the pressure drop across a classroom's windows is when the pressure differential between the windward and leeward sides of the building is known is relatively straightforward. Let's assume the pressure difference is 7 Pa. Since one usually wants to achieve a specific volume flow and the overflow openings have a constant size, the pressure drop at these overflow openings can be determined by a single measurement. Suppose the pressure drop across the overflow openings is 1.5 Pa each, then the total pressure drop across the windows of the two classrooms is 7 Pa-2*1.5 Pa = 4 Pa, and if the windows are opened equally, then there is a pressure drop of 2 Pa at the windows of each of the two classrooms.

Suppose a skylight window is controlled to Constantly supplying the classroom with fresh air. An air change of 1.5 h ^-1 is aimed for. The skylight has a length of 1.5 m and a height of 0.5 m, ie an area of 0.75 m ² . The spatial geometry of the class is 9 mx 9 mx 3 m, so the class has a volume of 243 m ³ . This means: the volume flow should be 364.5 m ³ /h.

The window manufacturers usually measure the air flow through their windows very precisely depending on the opening angle and the pressure difference (or calculate it using simulation calculations). The window given in the example has 0.75 m ² , ie 7500 cm ² . This area is divided into 7500 parts T _i , each with a side area of 1 cm×1 cm, and the flow velocity v _i (more precisely, its component in the spatial direction) is determined in this field. The total airflow is then:

The result for the window given in the example is: <b>Table 1</b> 2 pa 4 pa 6 pa 8 pa 10 Pa 12 Pa 3° ^165m3 /h 231 ^m3 /hr ^280m3 /h 327 ^m3 /h 366 ^m3 /h 403 ^m3 /h 5° 252 ^m3 /h 289 ^m3 /hr 374 ^m3 /h 413 ^m3 /h 462 ^m3 /h 514 ^m3 /h 10° 304 ^m3 /h 334 ^m3 /hr 415 ^m3 /h 458 ^m3 /h 521 ^m3 /h 563 ^m3 /h 15° 312 ^m3 /h 347 ^m3 /h 431 ^m3 /h 483 ^m3 /h 541 ^m3 /h 597 ^m3 /h 20° ^275m3 /h 349 ^m3 /h 437 ^m3 /h 483 ^m3 /h 544 ^m3 /h 601 ^m3 /h

You can see that the air exchange changes relatively little between 10°, 15° and 20° opening angle; between 3° and 10°, however, the change is relatively strong.

The values in this table can be approximated by the following empirical formula:

Here q _v means the air flow, α the opening angle of the window and Δp is the pressure difference across the window. By rearranging one can express α:

So if you aim for a volume flow of 364.5 m ³ /h, a pressure difference of 6 Pa results in an opening angle of around 4° and a pressure difference of 10 Pa results in an opening angle of 3°. With a pressure difference of 4 Pa, such a window is not sufficient. In practice, therefore, several tilting windows of this type will be provided.

Let's assume that there are two such bottom-hung windows in each classroom. Then only 364.5 m ³ /h / 2, i.e. around 182 m ³ /h, has to flow through each window. A pressure difference of 2 Pa results in an opening angle of 3.5° for each of the two windows.

These calculations are quite correct for a normal bottom hung window if the inside temperature and the outside temperature are relatively similar, as is usually the case in summer. In winter, however, the temperature difference can be significant, temperature differences of more than 30° are not uncommon. On such days, in addition to the air change calculated above, there is another air change that is thermally conditioned, as is shown in 2 is indicated: Warm air 1 flows through the window 22 (a narrow skylight tilting window) to the outside and cold air 2 flows inwards and sinks (because of the higher density) downwards. Of course, this effect can be taken into account and the window 22 can be closed further than is the result of the above calculation; nevertheless, the cold air sinks down, which is uncomfortable for a person sitting close to the wall with the window 22 and under this window 22. For this reason, one can attach a heater 4 under the window 22, as is generally the case with many windows anyway. Without further measures, however, the warm air rising from the radiator 4 would form a heat curtain that would not completely prevent the desired air exchange, but would greatly reduce it, which of course is undesirable. For this reason, a grille 3 with an apron is provided over the radiator 4 as a resistance to reducing the flow of warm air in front of the window. It is ideal when the reduced flow of hot air just prevents the cold air 2 from sinking down.

The radiator 4 is preferably guided by the outside temperature. The heating output is determined by the flow of cold air 2 so that there are no drafts and the room is not overheated, e.g. at 0°C outside temperature the radiator temperature is kept at 35°C.

Claims (4)

1. Building (11) with at least two rooms and a control unit for opening and closing of at least two windows (22, 23; 32, 33) in a building (11), for example in a school, wherein the control unit ensures the opening and closing of the windows (22, 23; 32, 33) depending on the weather conditions; wherein the control unit, taking into account the geometry of the windows (22, 23; 32, 33) and the size of the rooms (12, 13), calculates an opening angle of at least one window (22, 23; 32, 33) in each of the at least two rooms, which ensures that a selected air exchange is achieved, characterized in that the rooms (12, 13) and the corridors (14) of the building, respectively, are fluidically connected to each other, such that when the windows (22, 23; 32, 33) are opened, an air transport from one side of the building (11) to another side, in particular to the opposite side of the building (11) is made possible, and that said control unit also takes into account the differential pressure between these sides of the building (11).
2. Building (11) according to claim 1, characterized in that the control unit obtains the wind direction and the wind speed as input variables, and determines therefrom the differential pressure between the two sides of the building (11).
3. Building (11) according to claim 1 or 2, characterized in that a heating element (4) is provided beneath at least one window (22), wherein above the heating element (4), but below the window (22) a grid (3) having an apron as a resistance for reducing the flow of warm air in front of the window (22) is provided.
4. Arrangement of a building (11) having a control unit according to one of the claims 1 to 3 and at least one measuring device, characterized in that the at least one measuring device for determining the wind direction and the wind speed is provided at a minimum distance of 10 m, preferably 20 m, from the building (11).

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