EP0976988A1 - Air mixing unit for a room climatisation device - Google Patents

Abstract

The mixture unit (11) incorporates an induction nozzle (12) with a conical narrowed formation (13) for the primary air flow (V1). It has a nozzle cone (14) in the area of the narrowed formation (13), whereby the distance between the narrowed formation and the nozzle cone in an axial direction is variable. In the cover tube (15) of the induction nozzle are suction apertures (16) for secondary air (V2). An adjustment mechanism (17) is provided for the variation of the relative distance between the narrowed formation and the nozzle cone for the purpose of controlling the strength of the primary air flow (V1).

Description

The invention relates to a mixing unit for ventilation systems according to the generic term of Claim 1. It further relates to the use of Mixing unit.

Ventilation systems for air conditioning or ventilation of spaces are known. In particular there are, for example the document FR 2 720 484 a device for Temperature control of a room by feeding conditioned air. This becomes a constant Primary airflow before reaching a nozzle-shaped Outlet by targeted cooling in its temperature so set that after the addition of secondary air little different in temperature from the indoor air Fresh air flow results. This fresh air flow is used for Replace extracted air and to reduce the Room temperature without the appearance of being uncomfortable sensible air currents in the room.

It is also known to use conical air ducts Narrows in these concentrically arranged nozzle cones to use the strength of the airflow respectively to make the temporal flow rate adjustable. As An example is the document DE 196 17 384, in which the Mixing ratio of two gas volume flows through one Venturi nozzle via its motor-driven, axial movable nozzle needle is adjustable.

For the good mixing of different air flows it is further known, for example by swirling to bring them into intimate contact.

When air conditioning entire buildings with a variety rooms that are independent of each other can be designed different disadvantages occur. Let the rooms not independently and according to theirs Ventilate the way of use or air-condition it a relatively high energy consumption and / or too rigid air conditioning schedule, for example at public buildings in the evenings and on Weekends. Furthermore, there can be too voluminous ventilation ducts result or the comfort of the room user can by Drafts and / or noises are impaired.

For these and other reasons, the task of Invention, for more extensive ventilation systems Measures to indicate improvements in multiple Respect. In particular, the energy balance should of the systems can be improved and individual ventilation or air conditioning independent rooms at least not compared to increased installation costs known systems may be possible. Another job concerns the improvement of control options ventilation systems.

The solution to this problem is provided by the characteristic Part of the independent claims specified. The dependent ones Claims indicate embodiments of the invention.

The following are exemplary embodiments of the invention described with reference to the accompanying figures.

Figur 1

einen Längsschnitt durch eine erfindungsgemässe Mischungseinheit.

Figur 2

einen Längsschnitt durch eine Variante der Mischungseinheit 11 in Fig. 1.

Figur 3

ein prinzipielles Schema einer Gebäudeklimatisierungsanlage, in der erfindungsgemässe Mischungseinheiten 11 verwendet werden.

Figur 4

Diagramm aus den Regeln für die Kühllastberechnung vom Verband Schweizerischer Heizungs- und Lüftungsfirmen, Ausgabe 1980.

Show it:

Figure 1

a longitudinal section through an inventive mixing unit.

Figure 2

2 shows a longitudinal section through a variant of the mixing unit 11 in FIG. 1.

Figure 3

a schematic diagram of a building air conditioning system in which the mixing units 11 according to the invention are used.

Figure 4

Diagram from the rules for cooling load calculation by the Association of Swiss Heating and Ventilation Companies, 1980 edition.

Figure 1 shows the longitudinal section through a mixing unit 11 for ventilation and air conditioning purposes, that is for ventilation and Air conditioning. This unit 11 preferably comprises one cylindrical jacket tube 15, through which a Primary air flow V1 can be supplied. The mixing unit 11 further comprises a rectifier 19 for generating a laminar flow, a concentrically arranged, in essential conical induction nozzle 12 with a minimal Constriction 13, for example about a quarter of the Cross section of the casing tube 15 is one axially movable nozzle cone 14, and circular or cut rectangularly into the casing tube 15 Suction openings 16 for secondary air. The rectifier 19 and the induction nozzle 12 are rigid in the casing tube 15 arranged and so with respect to the suction openings 16 positioned that an exiting through the constriction 13 Primary air flow V1 a clear secondary air flow V2 generated through the openings 16 from the outside to the inside. The Nozzle cone 14, on the other hand, is supported and with one Adjustment mechanism 17 connected that he between two Extreme positions can be moved through solid line and dashed and hatched representation are indicated. The mechanism 17 can consist of levers and a push rod (as shown) be formed or any other way, for example under Use a pneumatic cylinder, or one electric linear motor.

The mixing unit 11 has the property that the from the primary air flow V1 and the secondary air flow V2 composing mixed air flow V3 essentially constant is independent of the strength of the primary air flow V1. This previously unknown property offers the possibility by changing the position of the nozzle cone 14 with respect to the induction nozzle 12, the mixing ratio between the primary air and the secondary air share in the To control fresh air flow V3 very significantly. At suitable dimensioning of the dimensions of nozzle 12, Nozzle cone 14 and openings 16 result further linear relationship between the change in position of the Nozzle cone 14 and the mixing ratio mentioned. This linear relationship offers good conditions for the construction of a simple air conditioning control loop, at which the mixing unit 11 serves as an actuator.

FIG. 2 shows a variant of the mixing unit 11 in FIG. 1. In this variant, the casing tube 15 extends Area of the nozzle 12 to a mixed air tube 18 with essential enlarged cross-section, for example doubled Cross-section. The suction openings 16 for the secondary air are in the conical transition region 20, for example between the casing tube 15 and the mixed air tube 18 arranged. This arrangement leads to the Nozzle constriction 13 significantly in the direction of flow reduced flow resistance, due to which the Share of secondary air in mixed air flow V3 compared to Unit 11 is massively enlarged according to Figure 1. The Nozzle cone 14 continues on the nozzle 12 and the Narrowing 13 matched that this completely lockable and thus the primary air flow V1 completely can be prevented.

Figure 3 shows a basic scheme of a more extensive Building air conditioning system 20, in the inventive Mixing units 11 are used. This attachment 20 essentially comprises a central air treatment 22, a main supply air line 24, a main exhaust air line 25, a any number of independent, too air-conditioning rooms 21.1, 21.2, ... or control areas, and regulation and control arranged in these rooms Air conditioning facilities.

The air treatment 22 comprises in a manner known per se a heat recovery system 31 connected to the main feed and -Exhaust air lines 24, 25 is connected. For vacuuming Fresh air and for extracting and expelling the used ones Air from the building is used by fans 32, 33 with approximately same output. In strands 24, 25 are in about maintaining constant pressures and temperatures appropriately controlled, regulated or selected. For the Exhaust air line 25, for example, the temperature + 22 ° C in Winter and + 26 ° C in summer not exceeded. For the Supply air line 24 is a temperature of approximately, for example +10 +/- 3 ° C suitable, regardless of the changing Outside air temperatures all year round Heating or cooling is essentially maintained.

The main strands 24, 25 run through the whole, not shown buildings and are by branches 24.1, 24.2, 25.1, 25.2 connected to all rooms 21.1, 21.2 etc.

In each of the rooms 21.1, 21.2, a mixing unit 11 with an actuator 47 for displacing the nozzle cone 14 is inserted into the casing tube 15 of the incoming branch 24.1, 24.2. This unit 11 is immediately followed by a mixer 41. A source air outlet 42 or any standard air outlet follows at any distance. A volume flow controller 43 is inserted in each branch 25.1, 25.2 of the main exhaust air line 25. For aesthetic reasons, the units 10, 41, 43 can be delimited from the usable volume of the respective room 21.1, 21.2 by an intermediate ceiling 44, which must be passable for the exhaust air, e.g. B. through slots. Local heating surfaces 45 are preferably also arranged in the rooms, for example radiators with engine or thermostatic valves. There is also at least one control sensor 46 for the room temperature. With more comfortable air conditioning, additional control sensors for the air humidity and / or the CO ₂ content of the air can be added.

The building air conditioning system 20 described so far works as follows: The central air conditioning unit 22 optimally recovers the heat energy contained in the main exhaust air duct 25 and provides conditioned fresh air for the air conditioning with parameters and pressure that remain approximately constant. In each of the rooms 21.1, 21.2, a control circuit acts largely independently of the conditions inside and outside the building and regardless of the conditions in the other rooms, the control sensor 46 of which is the room temperature, the air humidity and / or the CO ₂ content of the room air reports. The control loop adjusts the mixing unit 11 serving as an actuator, that is, it automatically brings the nozzle cone 14 into the position assigned to the control state. In this way, a primary air flow V1 associated with strength and consisting of the conditioned fresh air flows through the induction nozzle 12 from the main supply air duct 24. The intake openings 16 result in a secondary air flow V2 consisting of room air also associated with the strength. These two flows V1, V2 combine in the mixer 41 to form the mixed air flow V3 of approximately constant strength, the temperature of which is only a few degrees colder than the room temperature, for example 2K colder in winter and 7K in summer. This mixed air flow V3 escapes silently and draft-free into the room volume through the source air outlet 42 and cools and renews the room air. The quantity of exhaust air corresponding to the primary air quantity introduced is sucked off via the branch 25.1, 25.2 of the main exhaust air line 25, the respective volume flow controller 43 being operated analogously and in parallel with the nozzle cone 14 of the mixing unit 11.

It is obvious that the one described Air conditioning system 20 is capable of low Regulation effort a variety of independent Rooms 21.1, 21.2 independently of each other air conditioning. This optimizes user comfort and the air conditioning adapts to each Degree of utilization of the respective room 21.1, 21.2. In particular, the fresh air supply is reduced Not using the rooms striking what the amount of required heating energy in winter and cooling energy in Can massively reduce summer and energy requirements ventilation systems 20 sustainably reduced. The Building the necessary control loops is relative uncomplicated and inexpensive. In the Air conditioning system 20 is therefore a human needs and subjective feelings well adapted overall concept for building air conditioning optimal technical conditions and minimized Energy requirements. The same applies to appropriately designed Ventilation systems or ventilation and air conditioning systems.

• Bei der Mischungseinheit 11 kommt es darauf an, den relativen Abstand zwischen der Düse 12 und dem Konus 14 veränderbar zu machen. Dies kann auch dadurch geschehen, dass der Konus 14 ortsfest und die Düse 12 verschieblich angeordnet wird.
• Der Konus 14 lässt sich durch eine Einheit mit anderer als konischer, jedoch strömungstechnisch geeigneter Form ersetzen. Eine solche Form ist beispielsweise kugel- oder tropfenförmig.
• Die Düse 12 und der Konus 14 müssen nicht unbedingt rotationssymmetrisch ausgebildet und konzentrisch angeordnet sein. Andere Formen, beispielsweise im Querschnitt ovale, sind möglich.
• Die Mischungseinheit 11 kann für sehr hohe Räume auch ohne Mischluftrohr 18 und Ansaugöffnungen 16 vorgesehen werden, das heisst als Einheit mit regelbarer Freistrahldüse.
• Die Hauptstänge 24, 25 können unverzweigt oder auch verzweigt ausgebildet sein.
• Zum Aufbau der genannten Regelkreise in den Räumen 21.1, 21.2 ist der Stellantrieb 47 vorgesehen, der über den Verstellmechanismus 17 den Düsenkonus 14 in beiden Axialrichtungen verschiebbar macht. Für einfache Steuerungen ist es jedoch auch möglich, den Verstellmechanismus 17 manuell betätigbar zu machen, beispielsweise mittels einer Handkurbel.

In addition to the variants and configurations of the invention already mentioned, the following should also be mentioned explicitly:

• With the mixing unit 11 it is important to make the relative distance between the nozzle 12 and the cone 14 variable. This can also be done by arranging the cone 14 in a stationary manner and displacing the nozzle 12.
• The cone 14 can be replaced by a unit with a shape other than a conical shape that is, however, suitable in terms of flow. Such a shape is spherical or drop-shaped, for example.
• The nozzle 12 and the cone 14 do not necessarily have to be rotationally symmetrical and arranged concentrically. Other shapes, for example oval in cross section, are possible.
• The mixing unit 11 can also be provided for very high rooms without a mixed air pipe 18 and suction openings 16, that is to say as a unit with a controllable free jet nozzle.
• The main rods 24, 25 can be designed unbranched or branched.
• To set up the control loops mentioned in the rooms 21.1, 21.2, the actuator 47 is provided, which makes the nozzle cone 14 displaceable in both axial directions via the adjustment mechanism 17. For simple controls, however, it is also possible to make the adjustment mechanism 17 manually operable, for example by means of a hand crank.

• Die Mischungseinheit 11 ist auf Grund ihres Aufbaus mit konischer Düse 12 und zugeordnetem, axial verschieblichem Düsenkonus 14 in der Lage, den unter konstanten Druck ankommenden, konditionierten Primärluftstrom V1 in seiner Stärke zu steuern. Hierbei ergibt sich ein jeweils eindeutig in seiner Stärke zugeordneter Sekundärluftstrom V2 zur Bildung eines Mischluftstromes V3 etwa konstanter Stärke.
• Die Mischungseinheit 11 ermöglicht es auf Grund der stets annähernd konstanten Stärke des Mischluftstromes V3 den Primärluftstrom V1 den jeweiligen Bedürfnissen in einem Raum 21 anzupassen. Ist dieser unbenutzt, dann wird der Primärluftstrom V1 stark reduziert oder gar unterbunden. Ist der Raum 21 dagegen stark genutzt, dann kann der Primärluftstrom V3 massiv erhöht werden, ohne dass dabei der Mischluftstrom V3 eine wesentlich verminderte Temperatur annimmt.
• Die individuelle Regelbarkeit der Temperatur aller Räume in einem Gebäude durch Variation der jeweils zeitlich zugeführten Primärluftmengen ermöglicht es, die zentrale Primärluftaufbereitung 22 auf eine mittlere Leistung und damit kleiner als bei vergleichbaren Anlagen mit konstantem Volumenstrom und variabler Primärluft-Temperatur auszubilden. Dieser Vorteil resultiert vor allem aus Dimensionierungsgegebenheiten der zu klimatisierenden Gebäude und den unterschiedlichen Regelungsanordnungen.
• Als Regelgrössen können neben der Temperatur auch die Luftfeuchte und der CO₂-Gehalt der Raumluft dienen. Diese Eigenschaft erlaubt es, das Raumklima in den Räumen 21 individuell zu optimieren.

In summary, the advantages of the invention are listed again here:

• Because of its construction with a conical nozzle 12 and an associated, axially displaceable nozzle cone 14, the mixing unit 11 is able to control the strength of the conditioned primary air flow V1 arriving under constant pressure. This results in a secondary air flow V2 which is clearly assigned in terms of its strength in order to form a mixed air flow V3 of approximately constant strength.
• The mixing unit 11 makes it possible to adapt the primary air flow V1 to the respective needs in a room 21 on account of the always approximately constant strength of the mixed air flow V3. If this is not used, the primary air flow V1 is greatly reduced or even prevented. If, on the other hand, the space 21 is heavily used, the primary air flow V3 can be increased massively without the mixed air flow V3 taking on a significantly reduced temperature.
• The individual controllability of the temperature of all rooms in a building by varying the respective primary air quantities supplied in time makes it possible to design the central primary air preparation 22 to have an average output and thus smaller than in comparable systems with a constant volume flow and variable primary air temperature. This advantage results primarily from the dimensions of the buildings to be air-conditioned and the different control arrangements.
• In addition to the temperature, the humidity and the CO ₂ content of the room air can also serve as control variables. This property makes it possible to individually optimize the room climate in rooms 21.

The savings made by using a Mixing unit according to the invention for ventilation or Air conditioning of a number of independent rooms can be achieved can be e.g. by comparing the calculated Estimate energy costs, below for two Air conditioners for the same building (with about 30 rooms) be cited. Air conditioning 1 is a conventional one Air conditioning system in which the mixing unit according to the invention is not used. Air conditioning 2, however, is one Air conditioning system in which the mixing unit according to the invention is used.

t_A

Aussenlufttemperatur

t_ZUL

Zulufttemperatur

t_Am

Mittlere Aussenlufttemperatur

P_B

Barometrische Luftdruck

ρ

Dichte

G_Oel

Oelgewicht

E

Energiekosten

h

Stunde

h/a

Stunden pro Jahr

Fr.

Schweizer Franken

EWB

Elektrizitätswerk der Stadt Bern

WRG

Wärmerückgewinnung

WRG

Wärmerückgewinnungsfaktor

The following abbreviations are used in the calculations below:

t _A

Outside air temperature

t _ZUL

Supply air temperature

t _Am

Average outside air temperature

P _B

Barometric air pressure

ρ

density

G _oil

Oil weight

E

Energy costs

H

hour

Ha

Hours a year

Fr.

Swiss franc

EWB

Power station of the city of Bern

WRG

Heat recovery

WRG

Heat recovery factor

Air conditioner 1 (a conventional air conditioner) Energy costs:

Jahre: 1984 bis 1997, Monate: Oktober bis März

Winter Mitteltemperatur = 16.6/6 = + 2.76 °C

1. Calculation of the mean winter temperature according to monthly mean temperatures Bern Liebefeld (source reference Metereological Institute in Zurich, Switzerland)

Years : 1984 to 1997, months : October to March

Winter mean temperature = 16.6 / 6 = + 2.76 ° C

2. Calculation of the degree of ventilation according to the diagram according to Figure 4 (diagram from the rules for cooling load calculation by the Association of Swiss Heating and Ventilation Companies, 1980 edition)

Maximum value of t _{ZUL set} to + 17 ° C

Annual hours with t _A <+ 17 ° C

= 3,500 h / a

Degree of ventilation daily hours Bern t _A <+ 17 ° C

= 39,500 ° Kh / a

Degree of ventilation daily hours Bern t _A <+ 2.76 ° C

= 4,000 ° Kh / a

Effective heating rounds

= 35,500 ° Kh / a

Zuluftmenge V = 9200 m³/h = 2.55 m³/s

t_Am = (2.76 + 15)/2 = 8.9 °C und P_B = 950 mbar

ρ bei t_Am = 1.293 * (950/1013) * (273/282.9) = 1.18 kg/m³

Assuming a ventilation requirement of 84h per week and with the following distribution of the system runtime: 5 days at 14h and 1 day at 8h, the runtime is 78h per week. The reduction factor is therefore 78/84 = 0.9285.

Supply air volume V = 9200 m ³ / h = 2.55 m ³ / s

t _Am = (2.76 + 15) / 2 = 8.9 ° C and P _B = 950 mbar

ρ at t _Am = 1,293 * (950/1013) * (273 / 282.9) = 1.18 kg / m ³

3. Calculation of the heat requirement

Q _H = 2.55 * 1.180 * 1.005 * 35'500 * 0.9285 = 98'833 kWh

4. Calculation of the oil consumption with a total heating distribution efficiency of η = 0.7

G _{of oil} = 98'833 kWh / (0.7 * 11:36 kWh / kg) = 12'428 kg

E = 12'428 kg * 0,3 Fr./kg = Fr. 3'728.50

4.1 Calculation of heating costs without heat recovery

E = 12'428 kg * 0.3 Fr./kg = Fr.3'728.50

E = 98.833 kWh * 56 Fr./MWh = Fr. 5'534.--

4.2 District heating costs winter tariff Bern Fr. 56 .-- / Mwh

E = 98,833 kWh * 56 Fr./MWh = Fr.5,534 .--

The required efficiency of heat recovery at -11 ° C outside temperature is approx. 85%. The required heating can therefore only partially with a Heat recovery are covered, i.e. It is a additional air heater required.

5. Calculation of electricity savings 5.1 Calculating the duration of the day, high tariff

5 days from 6 a.m. to 10 p.m.

= 14.0 h

Saturday from 6 a.m. to 2 p.m.

= 8 h

Total hours per week

78 h

Total hours of the year 50 x 78

= 3900 h

6. Calculation of electricity consumption high tariff

Winter semester total kWh

6725 according to table 1

Summer semester total kWh

6725 according to table 2

Subtotal

13452

Share of high tariff 100%

7. Calculation of electricity costs including the service price

Electricity tariff according to the EWB bill

Effective electricity price

High tariff 0.18 CHF / kWh
Low tariff 0.115 CHF / kWh

8. Calculation of the annual costs

High tariff 13452 kWh at 0.18 Fr./kWh

CHF 2,421

warmth District heating with heat recovery Ø 75%

CHF 553 .--

Total total

CHF 2,974

Air conditioning system 2 (uses mixing unit according to the invention) Energy costs :

Jahre: 1984 bis 1997, Monate: Oktober bis März

Winter Mitteltemperatur = 16.6/6 = + 2.76 °C

1. Calculation of the mean winter temperature according to monthly mean temperatures Bern Liebefeld ( source reference Metereological Institute in Zurich, Switzerland)

Years : 1984 to 1997, months : October to March

Winter mean temperature = 16.6 / 6 = + 2.76 ° C

2. Calculation of the degree of ventilation according to the diagram according to Figure 4 (diagram from the rules for cooling load calculation by the Association of Swiss Heating and Ventilation Companies, 1980 edition)

Maximum value of t _{ZUL set} to + 12 ° C

Annual number of hours with t _A <+ 12 ° C

= 2,700 h / a

Degree of ventilation daily hours Bern t _A <+ 12 ° C

= 24,500 ° Kh / a

Degree of ventilation daily hours Bern t _A <+ 2.76 ° C

= 4,000 ° Kh / a

Effective heating hours

= 20,500 ° Kh / a

Maximale Zuluftmenge V_max = 6338 m³/h = 1.76 m³/s

Durchschnittliche Zuluftmenge
   (6338+4240)/2 = 5289 m³/h = 1.47 m³/s

t_Am = (2.76 + 12)/2 = 7.38 °C und P_B = 950 mbar

ρ bei t_Am = 1.293 * (950/1013) * (273/280.4) = 1.17 kg/m³

Assuming a ventilation requirement of 84h per week and with the following distribution of the system runtime: 5 days at 14h and 1 day at 8h, the runtime is 78h per week. The reduction factor is therefore 78/84 = 0.9285.

Maximum supply air volume V _max = 6338 m ³ / h = 1.76 m ³ / s

Average supply air volume
(6338 + 4240) / 2 = 5289 m ³ / h = 1.47 m ³ / s

t _Am = (2.76 + 12) / 2 = 7.38 ° C and P _B = 950 mbar

ρ at t _Am = 1,293 * (950/1013) * (273 / 280.4) = 1.17 kg / m ³

3. Calculation of the heat requirement

Q _H = 1.47 * 1.170 * 1.005 * 20'500 * 0.9285 = 33'163 kWh

4. Calculation of the oil consumption with a total heating distribution efficiency of η = 0.7

G _{of oil} = 33'163 kWh / (0.7 * 11:36 kWh / kg) = 4'170 kg

4.1 Calculation of heating costs without heat recovery

E = 4'170 kg * 0.3 Fr./kg = Fr. 1'251 .--

4.2 District heating costs winter tariff Bern Fr. 56 .-- / Mwh

E = 33'163 kWh * 56 Fr./MWh = Fr. 1'857 .--

The required efficiency of heat recovery at -11 ° C outside temperature is approx. 70%. The required heating requirements can therefore be 100% through a Heat recovery can be covered.

5. Calculation of electricity savings 5.1 Calculating the duration of the day, high tariff

5 days from 6 a.m. to 10 p.m.

= 14.0 h

Saturday from 6 a.m. to 2 p.m.

= 8 h

Total hours per week

78 h

Total hours of the year 50 x 78

= 3900 h

6. Calculation of electricity consumption high tariff

Winter semester total kWh

3,882 according to Table 1

Summer semester total kWh

3,882 according to Table 2

Subtotal

7,764

Share of high tariff 100%

7. Calculation of electricity costs including the service price

Electricity tariff according to the EWB bill

Effective electricity price

High tariff 0.18 CHF / kWh
Low tariff 0.115 CHF / kWh

8. Calculation of the annual costs

High tariff 7'764 kWh at 0.18 Fr./kWh

CHF 1,397

warmth District heating with heat recovery

Fr. 0 .--

Total total

CHF 1,397

Claims (12)

Mixing unit (11) for air conditioning systems (20) for mixing suitably tempered primary air with secondary air from the room to be air-conditioned (21.1, 21.2) to form a mixed air flow,
which mixing unit (11) is characterized by
that it includes the following means (a) an induction nozzle (12) with a conical constriction (13) for the primary air flow (V1), (b) a nozzle cone (14) which is arranged in the region of the constriction (13), the distance between the constriction (13) and the nozzle cone (14) being changeable in the axial direction, and (c) In the casing tube (15) of the suction nozzle (12) arranged suction openings (16) for the secondary air. Mixing unit (11) according to claim 1,
characterized,
that an adjustment mechanism (17) is provided for changing the relative distance between the constriction (13) and the nozzle cone (14) for the purpose of controlling the strength of the primary air flow (V1). Mixing unit (11) according to claim 1 or 2,
characterized,
that the constriction (13) is stationary and the nozzle cone (14) is designed to be displaceable. Mixing unit (11) according to one of Claims 1 to 3,
characterized,
that the nozzle cone (14) is axially displaceable relative to the constriction (13). Mixing unit (11) according to one of Claims 1 to 4,
characterized,
that the nozzle cone (14) and the constriction (13) are shaped and matched to one another such that there is an approximately linear dependence between the primary air flow (V1) and the relative distance between the constriction (13) and the nozzle cone (14). Mixing unit (11) according to one of Claims 1 to 4, characterized in that
that the nozzle cone (14) and the constriction (13) are shaped and matched to one another so that the primary air flow (V1) can be completely prevented. Mixing unit (11) according to one of Claims 1 to 6, characterized in that
that the adjustment mechanism (17) is coupled to a controllable drive. Mixing unit (11) according to one of Claims 1 to 6, characterized in that
that the adjustment mechanism (17) can be operated manually. Mixing unit (11) according to one of Claims 1 to 8, characterized in that
that the induction nozzle (12) and the nozzle cone (14) are set up and dimensioned such that a reduction in the axial distance between these two means reduces the primary air flow (V1) and increases the secondary air flow (V2). Use of mixing unit 11 according to one of claims 1 to 9 for ventilation or air conditioning of a plurality of mutually independent rooms (21.1, 21.2),
characterized, that a single source (24) is provided for providing the primary air, and that each room (21.1, 21.2) is assigned a mixing unit (11) which controls the respective current strength of the primary air (V1) arriving from the source (24) according to the respective room climate parameters. Use according to claim 10,
characterized,
that in each room (21.1, 21.2) the only room climate parameter is a temperature limit. Use according to claim 10,
characterized,
that in each room (21.1, 21.2) the room temperature, air humidity and / or the CO ₂ content of the air can be used as room climate parameters.

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