WO2015059038A1

WO2015059038A1 - Actuating unit for a heat exchanger, heat exchanger, and a method for controlling a heat exchanger

Info

Publication number: WO2015059038A1
Application number: PCT/EP2014/072287
Authority: WO
Inventors: Ulrich ZIEGLTRUM
Original assignee: Güntner Gmbh & Co. Kg
Priority date: 2013-10-22
Filing date: 2014-10-17
Publication date: 2015-04-30
Also published as: GB2534081B; US20160252313A1; GB2534081A; DE112014004840A5

Abstract

The invention relates to an actuating unit (1) for a heat exchanger (2), wherein the actuating unit (1) receives information on an environmental temperature, an environmental humidity, a water volume of a wetting device (3) for wetting the heat exchanger (2), a speed (41) of a ventilator (4) of the heat exchanger (2), and a geodetic height. The actuating unit (1) is intended to calculate a spraying water volume (31), in dependence on the cited information, and the actuating unit (1) adjusts the wetting device (3) such that the wetting device (3) wets the heat exchanger (2) with the calculated spraying water volume.

Description

Control unit for a heat exchanger, heat exchanger and a method for controlling a heat exchanger. The invention relates to a drive unit for a heat exchanger according to the preamble of independent claim 1, a

Heat exchanger comprising a drive unit according to the preamble of independent claim 7 and a method for controlling a

Heat exchanger according to the preamble of independent claim 1 1.

Today, products, processes or media have to be cooled or frozen in various industries. Come for this

Industrial refrigeration systems are used, which are usually for large

Refrigerating capacities are designed, and therefore have a not inconsiderable energy needs.

To reduce this energy demand, various solutions are already known. On the one hand, a design of the heat exchanger can be changed, for example, a wetting device can be provided, on the other hand, the operating state of individual

Heat exchanger devices, such as a fan or the wetting device, are controlled or controlled. In the

WO2010 / 040635 A1 is, for example, a wetting of the

Heat exchanger disclosed. The wetting of the heat exchanger thereby causes the energy consumption of the fans can be minimized or the efficiency of the heat exchanger is increased.

In the case of these so-called hybrid coolers or hybrid dry coolers, as also disclosed, for example, in WO90 / 15299 or EP 428 647 B1, this flows through to be cooled gaseous or liquid medium of the primary cooling circuit, a heat exchanger, and indicates the dissipated heat over

Transfer element and / or more heat exchange ribs partly as sensitive and partly as latent heat to a replacement fluid. One or more fans thereby promote the replacement fluid as an air flow through the heat exchanger and may have a variable speed. The removal of the latent heat is carried out by a wetting fluid as a drop-forming liquid film on the air side is placed on the heat exchanger. Immediately below the heat exchanger, the excess wetting fluid drips back into a collection cup.

The disadvantage here is that a quantity of spray water of the wetting fluid does not correspond to an evaporation amount, so that an excess of water is produced, which must be collected in the collection bowl. Another disadvantage here is that a formation of impurities, such as bacteria, ie Legionella, must be avoided. Similarly, the speed of the fan is not adapted to the amount of water spray, so that the

Total heat exchanger is uneconomical and not energy efficient.

Therefore, it is an object of the invention, a drive unit, a

Heat exchanger and a method for controlling a

Heat exchanger for an economic and / or energy-efficient operation of the heat exchanger to provide.

This object is achieved by a drive unit for a heat exchanger with the features of claim 1, a heat exchanger with the features of claim 7 and a method for controlling a

Heat exchanger solved with the features of claim 1 1. According to the invention, a drive unit for a heat exchanger is proposed. The drive unit receives information about

an ambient temperature, an ambient humidity, an amount of water of a wetting device for wetting the heat exchanger, a speed of a fan of the heat exchanger and / or a

geodesic height. The drive unit is provided, depending on the information mentioned, to calculate a quantity of spray water and the drive unit adjusts the wetting device in such a way that the wetting device measures the heat exchanger with the calculated one

Moistened amount of spray water.

The heat exchanger includes a module that may include, for example, a plurality of transmission elements and a plurality of heat exchange fins. The transmission elements may be designed as tubes or as an extruded profile with a plurality of channels. The heat exchange ribs, for example, slats or folded metal strips in

Be slat shape. The heat exchange ribs can with the

Transmission elements be thermally conductively connected and can form an air duct. The heat exchanger may further comprise a fan, wherein the fan in the air duct can generate an air flow. In addition, a wetting device for the

Heat exchanger may be provided, wherein the wetting device is arranged on the heat exchanger and wets the heat exchanger with a wetting fluid.

The drive unit may be a control unit or a controller that can control and regulate, or a programmable memory element with a fixed programmable function. The control unit can also receive and send information and technical

Perform calculations. The control unit receives information about the ambient temperature, the ambient humidity, the amount of water a wetting device for wetting the heat exchanger, a speed of a fan of the heat exchanger and a geodetic height. The drive unit may receive the information, for example from one or more sensors, with which the information is measured or calculated, for example. However, the drive unit can also receive further information, for example from further sensors, a control unit or a further drive unit. The drive unit may be formed as part of the heat exchanger, so for example inside or outside of a housing on

Heat exchanger attached, or regardless of

Heat exchanger can be arranged, for example, within a room or a control cabinet. The drive unit can be connected to the sensors, the control unit or a further drive unit and can communicate with it, for example by means of a cable, or wirelessly, for example by radio. Under tax is to be understood that

For example, an operating mode and / or the speed and / or the amount of water can be changed by means of the drive unit. Under rules is to be understood that, for example, information about the

Ambient temperature, the ambient humidity, the amount of water, the speed and the geodetic altitude detected or measured and a calculated or predetermined value can be maintained to

for example, to influence or maintain a liquefaction temperature.

The ambient temperature can be measured with a temperature sensor. The temperature sensor may be, for example, a hot conductor, a PTC thermistor, a silicon sensor, a ceramic PTC thermistor, a thermal sensor or a thermocouple. The temperature sensor can measure the information about the ambient temperature and send it to the drive unit. The temperature sensor may be formed as part of the heat exchanger. But the temperature sensor can also, for example, on a housing of the Heat exchanger or be arranged in the immediate vicinity of the Wärmeausrauscher.

The ambient humidity can be measured with a humidity sensor. The humidity sensor may be a hygrometer, for example a

Absorption hygrometer, a psychrometer or a

Dew point hygrometer. The humidity sensor can send the information about the ambient humidity to the control unit. The humidity sensor may be formed as part of the heat exchanger. However, the moisture sensor can also be arranged on a housing of the heat exchanger or in the immediate vicinity of the heat emanator.

The control unit also receives information about a

Water quantity of the wetting device for wetting the

Heat exchanger, a speed of a fan of the

Heat exchanger and / or a geodetic height. The amount of water can be measured with a water meter, for example with a flowmeter or a meter. For example, the meter can measure the amount of water within any period of time, and the meter can measure the amount of water per unit of time (such as:

Flow; Volume flow). The water meter may be arranged, for example, on the heat exchanger or the wetting device, in particular on a supply line for a wetting fluid, which may be in particular water, to the wetting device. The speed of the fan of the heat exchanger can be received by a control unit, which can be signal-connected to the fan and can adjust the fan. But it can also be connected to the drive signal connected to the fan and adjust the fan. The geodetic height can be measured either by means of a height sensor or the information about the geodetic height of the heat exchanger can be set on the drive unit. The geodetic height can with a Height sensor can be measured. Under an altimeter can

For example, a measurement of the geodesic height by means of a

Leveling device or by means of GPS or GNSS satellites or by barometric altimeter. The drive unit is provided depending on the

Information about environmental conditions, such as the

Ambient temperature, the ambient humidity, the amount of water, the speed and the geodetic altitude to calculate a quantity of water spray. Under the amount of water or the amount of water spray can be understood as an amount of wetting fluid, such as water or fresh water. In addition, the drive unit can the

Adjust the wetting device so that the wetting agent wets the heat exchanger with the calculated quantity of spray water. The wetting device may comprise a nozzle, for example a flat jet or hollow cone nozzle, and a feed line and be arranged on the heat exchanger. The wetting device can be the heat exchanger, in particular the module, ie the transmission elements and / or the heat transfer elements, or a moistening, the

for example, from cardboard or a cardboard-like material or a plastic, with or without coating, can be, wet. The

Moistening mat can be arranged, for example, above the heat exchanger and / or laterally on the heat exchanger and / or between a plurality of modules. The wetting device can be arranged and wet, for example, above and / or laterally and / or between a plurality of modules. The wetting device can the

So heat exchanger from one or more spatial directions. The wetting device may also include one or more irrigation hoses, which lie on the moistening mat and wet them. The wetting fluid can on the wetted

Heat exchanger evaporate, with a spray water excess can proceed unevaporated. Thus, due to the wetting device by means of evaporative cooling, an additional cooling effect can be achieved.

Advantageously, by means of the drive unit, for example due to the calculated quantity of spray water, the operation of the heat exchanger can be adapted very precisely to the ambient conditions of the heat exchanger. The heat exchanger comes in running with less water and the drive unit allows operation of the heat exchanger is more economical and / or energy efficient. Also, the heat exchanger can be operated without a water circulation, so that can be dispensed with a complex water treatment. In addition, advantageously, since only fresh water on the

Heat exchanger is given, a Legionellenbildung be avoided.

In an embodiment of the invention, the drive unit receives information about a geodetic altitude and / or provides the calculated

Sprühwassermenge an estimated value for an evaporation amount. The amount of water spray can be calculated such that the

Amount of spray water with which the wetting device the

Heat exchanger wetted, almost completely evaporated. As already mentioned, a small excess of spray water can proceed undiluted. Advantageously, the heat exchanger can be very accurately wetted only with as much water spray as can evaporate, therefore can

For example, fresh water can be used and can be dispensed with the water circulation for the wetting fluid. In an embodiment of the invention, the drive unit is provided to calculate a cost function as a function of a parameter and to set the heat exchanger such that the cost function is minimal. The parameter is designed as the water price for the wetting device and / or as the electricity price for the fan. Under the cost function can be a sum over one or more products from for example water price times the amount of water and / or electricity price times an amount of electricity, so a consumed by the fan power amount to be understood. If the cost function is minimal, the amount of water can be calculated

Sprühge amount or a cost-optimal amount of spray water correspond, and / or the amount of electricity cost-optimal amount of electricity. Cost-optimal means that the cost of operating the heat exchanger is minimal and / or energy efficient.

Advantageously, the drive unit, the heat exchanger thus a particularly energy-efficient and / or cost-efficient

Operate operating state or operating mode. The cost function, and hence the cost of operating the heat exchanger, may be minimized depending on the information present to the drive unit.

In an embodiment of the invention, the drive unit in addition to the

Amount of spray water a set speed of the fan. In addition, the drive unit adjusts the wetting device by means of a PI controller. The advantage is that the desired speed of the fan is a speed that is particularly adapted to the environmental conditions, in particular corresponds to a speed that minimizes the cost function. Thus, the

Heat exchanger, in particular the fan and the

Wetting device, in a particularly cost-optimal or

economical and energy-efficient operating mode.

According to the invention, a heat exchanger comprising a drive unit is proposed below. The drive unit according to the invention can thus be part of a heat exchanger. Advantage is that the

Wetting device and the fan of the heat exchanger by means of the drive unit depending on the ambient conditions are adjustable, for example, in one or more modes of operation, thus enabling operation of the heat exchanger, in which the amount of water and / or amount of electricity optimal, so minimal. In an embodiment of the invention, the heat exchanger comprises a module containing a plurality of transmission elements and a plurality of heat exchange fins. The heat exchange ribs are thermally conductively connected to the transmission elements and form an air duct. A fan creates an air flow in the air duct. A wetting device is arranged on the heat exchanger and wets the heat exchanger with a wetting fluid.

The transmission element can be designed, for example, as a tube or instead as an extruded profile with a multiplicity of channels. The heat exchange fins may be slats or sheet metal strips that are canted. The module, so the transmission elements and / or the heat exchange ribs may be made of a good thermal conductivity material, such as aluminum or copper or stainless steel.

The heat exchanger may be a laminated heat exchanger. The laminated heat exchanger can in the simplest case a pipe as

Transmission element for passing a fluid and a plurality of fins include as heat exchange ribs. The heat exchange fins may be connected to the pipe and in operation communicate with one another. This construction is particularly expedient if the replacement fluid is gaseous and, for example, consists of ambient air, since this has a comparatively low heat transfer coefficient, which is due to a correspondingly large surface area of the lamellae

can be compensated. Of course, the laminated

Heat exchangers may also contain a plurality of tubes for more than one fluid or the tubes may be connected in parallel and / or in series as needed. The slats or pipes can be a good one

thermally conductive material, for example aluminum or copper or stainless steel. The fluid may be liquid or gaseous and a Heat transfer medium, for example, a refrigerant to be. The

Exchange fluid may be liquid or gaseous, for example air.

The production of the laminated heat exchanger can be carried out according to a standardized process. The slats can be punched, for example, with a press and a special tool and placed in packages to each other. The tubes can be inserted into the slats and either expanded mechanically or hydraulically, so that a very good contact and thus a good heat transfer between the tube and slat can occur. The individual tubes can be connected to one another, for example, by means of bends and / or a collection and distribution tube.

The heat exchanger may also be a plate or a microchannel heat exchanger. The transmission element of the microchannel heat exchanger can be embodied, for example, as an extruded profile which is made of a material with good thermal conductivity, such as aluminum. The transfer members may include a plurality of channels having a diameter of, for example, 0.5 to 3 mm for the heat transfer medium. The heat exchange ribs can be folded sheet metal strips, for example in lamellar form.

Between two closely spaced extrusion profiles, the metal strips can be arranged, for example, aluminum sheet strips, so that by alternately juxtaposition of metal strips and

Extruded profiles a module is created. This package can then be completely soldered in a soldering oven.

The heat exchange fins are with the transmission elements

thermally conductively connected and form an air duct. A fan creates an air flow in the air duct. The heat exchanger may include one or more fans. The air flow can take place through the heat exchanger, in particular through the module. Advantageously, the fan with a variable speed, in particular a target speed, which can be adjusted by means of the drive unit, are operated.

In addition, a wetting device may be provided for the heat exchanger. The wetting device may comprise a nozzle, for example a flat jet or hollow cone nozzle, and a feed line and be arranged on the heat exchanger. The wetting device can wet the heat exchanger, in particular the module, ie the transmission elements and / or the heat transfer elements. This can be the

Wetting device, for example, be arranged above and / or laterally and / or between several modules and wet. The

Wetting device can thus wet the heat exchanger from one or more spatial directions. In this case, the fluid, the

for example, the transmission elements flows through, and which discharges a dissipated heat via the heat exchange ribs partly as sensitive and partly as latent heat to the air flow, be dissipated. The removal of the latent heat can be done for example by the wetting fluid. For this purpose, the wetting fluid can be a drop-forming

Form liquid film on the heat exchanger, in particular the module, so the transmission element and / or the heat exchange fins, or a moistening mat. The moistening mat can be arranged, for example, above the heat exchanger and / or laterally on the heat exchanger and / or between a plurality of modules. The

Wetting device can be arranged and wet, for example, above and / or laterally and / or between several modules. The

Wetting device can thus wet the heat exchanger from one or more spatial directions. Advantageously, the

Actuator set the wetting device such that the

Wetting device wets the heat exchanger with a calculated amount of spray water. The amount of water spray can thus very accurately adapted to the environmental conditions of the heat exchanger and the heat exchanger comes in the operating state with less

Wetting fluid, so it is more economical and / or more energy efficient.

In an embodiment of the invention, a fan associated control unit receives a target speed of the drive unit and the

Control unit is provided to set the fan to the target speed. The wetting device is also intended to wet the module, the transfer elements and / or the heat exchange ribs and / or a moistening mat with liquid. Either the drive unit can adjust the fan or the

Control unit receives the target speed from the drive unit. In the second case, the control unit can adjust the fan, ie control and regulate. A control unit can thus be understood to mean a device for controlling and regulating the fan. Thus, the heat exchanger can be retrofitted with already existing fan and control unit advantageously with a drive unit.

The wetting device can wet the module, that is to say the transfer element and / or the heat exchange ribs, or else one or more moistening mats, which can be arranged on the heat exchanger. Advantageously, so many different embodiments can be illustrated, without moistening the spray water can evaporate directly, with moistening the spray water can be stored for example at the heat exchanger.

According to the invention, a method for controlling a

Heat exchanger proposed, depending on a

Ambient temperature, an ambient humidity, an amount of water a wetting device for wetting the heat exchanger, a

Speed of a fan of the heat exchanger and / or a geodetic height a quantity of spray water is calculated. The Wetting device is adjusted so that the heat exchanger is wetted with the calculated amount of spray water.

The method provides a function of environmental conditions, such as the ambient temperature, the ambient humidity, the amount of water, the speed and the geodetic height

To calculate amount of spray water. The amount of water and the

Amount of spray water can be a wetting fluid, for example water, in particular fresh water. The wetting device can be adjusted so that the heat exchanger is wetted with the calculated amount of spray water. Under the wetting of the

Heat exchanger can be understood that the

Wetting device a transmission element and / or a

Heat exchange rib and / or a moistening mat is wetted with the fluid. Advantageously, the amount of spray water can thus be adapted very precisely to the ambient conditions of the heat exchanger and the heat exchanger comes in the operating state with less water and is therefore more economical and / or energy efficient. Also, the heat exchanger can be operated without a water circulation, so that can be dispensed with a complex water treatment. The method can be carried out with the described drive unit and / or the described heat exchanger.

In an embodiment of the invention, the fan with a maximum target speed and the wetting device are set with a maximum amount of spray water in a first operating mode. By means of a

Condensing temperature, an operating mode can be derived. Under a liquefaction temperature can be understood, for example in dry coolers or capacitors, an outlet temperature of the fluid. The liquefaction temperature can be dependent on the ambient temperature. In addition, at a drive unit, a target speed of the fan and the amount of spray water in dependence on a condensing setpoint. The liquefaction setpoint can be understood to mean a minimum liquefaction temperature.

In the first operating mode, the condensing setpoint can not be reached due to a high ambient temperature and the

Heat exchanger can be operated in a full load operation. The fan can with a maximum target speed and the

Wetting device can be set with a maximum amount of water spray. In the first operating mode, the condensing temperature may follow the ambient temperature.

In a refinement of the invention, in a second operating mode the quantity of spray water is calculated in such a way that it represents an estimated value for an evaporation amount. The second operating mode can be as

Part load operation without efficiency mode are described. The fans may be in a controlled mode, i. the desired speed can be set to any desired speed. In addition, the condensing set point can be reached.

If the set minimum condensing temperature is reached, for example, the setpoint speed of the fan can be set to a lower speed than the maximum speed in order to avoid a further decrease in the liquefaction temperature. In addition, the

Wetting device are set such that the

Heat exchanger is wetted with the calculated amount of spray water, whereby the liquefaction temperature is lowered and by a resulting cooling, a performance of the heat exchanger is increased. In the second mode of operation, the amount of spray water is calculated to be an estimate of an amount of evaporation. For this purpose, the drive unit, the amount of water spray on the basis of

Environmental conditions, so for example based on the Ambient humidity, the speed, the amount of water and the

Calculate ambient temperature in such a way that the amount of water spray is evaporated as completely as possible. Advantageously, so the

Heat exchanger energy efficient and economical operation. In addition, so on a water circulation and on an elaborate

Water treatment can be dispensed with.

In a refinement of the invention, in a third operating mode, a cost function is calculated as a function of a parameter, and the heat exchanger is adjusted such that the cost function is minimal. The third mode of operation may be considered a partial load mode with efficiency mode

to be discribed. The fans may be in controlled operation, i. the target speed can be set to a lower speed than the maximum speed. In addition, the

Condensing setpoint can be achieved. In the third operating mode, the amount of spray water and the setpoint speed are set such that the cost function depends on a

Calculated parameters and set the heat exchanger so that the cost function is minimal. The parameters can be designed as water price and / or as electricity price. The minimum cost function can thus be calculated for example on the basis of predetermined water and electricity costs and a cost-efficient operating point of the heat exchanger can be set. As a result, the heat exchanger is operated in a very energy-efficient mode, since water and electricity costs are minimal. In an embodiment of the invention, the amount of spray water is calculated as a function of the geodetic height and / or derived as a function of a liquefaction temperature, an operating mode of the heat exchanger. By means of the drive unit can be based on the

Environmental conditions are calculated, which operating mode optimal is, so whether it is cheaper, for example heat through

Dissipate evaporative cold or by convection. Depending on whether the condensing setpoint is reached, the controller is in full load or partial load mode. The efficiency mode can be activated in the control unit.

A great advantage of the inventive drive unit, the

heat exchanger according to the invention and the inventive method is the setting of the various operating modes. As a result, an optimal adapted to the environmental conditions operation and the interception of leaps in performance is possible at any time. In contrast to the prior art, the control of the heat exchanger will thus be improved overall because it is set with a higher precision.

Further advantageous measures and preferred process guides emerge from the dependent claims.

Further advantages will become apparent from the following description of the figures. In the figures, an embodiment of the invention is shown. The figures, the description of the figures and the claims contain numerous features in combination. The skilled person will conveniently consider the features individually and to meaningful further combinations

sum up.

In the following, the invention is described both in apparatus and in

procedural terms explained with reference to embodiments with reference to the drawings. In the schematic

Show drawing:

Fig. 1 is a schematic representation of a first embodiment of a heat exchanger with a drive unit; a schematic representation of a second

Embodiment of a heat exchanger with wetting device and a drive unit; a schematic representation of a time-temperature diagram for explaining the method; a schematic representation of a third embodiment of a heat exchanger with wetting device.

Fig. 1 shows a schematic representation of a first embodiment of a heat exchanger 2 with a drive unit. Of the

Heat exchanger 2 comprises a module 5 and a fan 4. The module 5 in turn contains a plurality of transmission elements and a plurality

Heat exchange ribs, which are thermally conductively connected to the transmission elements and form an air duct. The fan 4 generates an air flow in the air duct. In addition, a wetting device (3, see FIG. 2) is arranged on the heat exchanger 2, which the

Heat exchanger 2 wetted with a wetting fluid.

In addition, a drive unit 1 is provided on the heat exchanger 2. The drive unit 1 receives information about a

Environmental parameters, in particular via

An ambient temperature,

• ambient humidity,

A quantity of water from a wetting device 3 for wetting the heat exchanger 2,

· A speed 41 of a fan 4 of the heat exchanger 2 and / or • a geodesic height.

The ambient temperature is measured by means of a temperature sensor 8 and receive the information about the ambient temperature of the drive unit 1. Likewise, the ambient humidity is determined by means of a

Humidity sensor 7 measured and receive the information about the ambient humidity of the drive unit 1. The amount of water the

Wetting 3 is measured with a water meter 1 1, for example with one with a flow meter or a meter. The

Speed 41 of the fan 4 is received by the drive unit 1, which is signal-connected to the fan 4. The geodetic height is measured by a height sensor 9 and the geodetic height information is received by the driving unit 1. The drive unit 1 calculates, depending on the information mentioned, a

Amount of spray water 31 and sets the wetting direction 3 in such a way that the wetting direction 3 wets the heat exchanger 2 with the calculated amount of spray water 31.

In Fig. 2 is a schematic representation of a second

Embodiment of a heat exchanger 2 with wetting 3 and a drive unit shown. FIG. 2 essentially corresponds to FIG. 1, which is why only the differences are discussed. In this case, a control unit 6 is provided, which adjusts the fan 4. The

Drive unit 1 is signal-connected to the control unit 6. The

Drive unit 1 receives the rotational speed 41 from the control unit 6, and the control unit receives a target rotational speed from the drive unit 1. As already mentioned, the control unit 6 and the control unit 1 can also be designed in one piece, that is to say the control unit 6 as part of the drive unit 1. The wetting device 3 is arranged such that the modules 5 are wetted from the interior of the heat exchanger 2, for example by means of spray heads. Also, the heat exchanger is operated without a water circulation, so that can be dispensed with a complex water treatment.

Fig. 3 shows a schematic representation of a time-temperature diagram for explaining the method. On the abscissa is a number

Operating hours of the hours per year n [h / a] and on the ordinate the

Temperature T in degrees C applied. The three functional curves show the cumulated ambient and condensing temperature as a function of the number of hours. The function curve 95 corresponds to the curve of the cumulated ambient temperature, the function curve 94 corresponds to the course of the cumulative liquefaction temperature with wetting device 3, and the function curve 93 corresponds to the cumulative one

Condensing temperature without wetting device 3. The vertical lines 90, 91 delimit different operating modes. Dashed vertical line 90 is the demarcation between a full load operation (range 2) and a dry mode partial load operation (range to the right of dashed vertical line 90). The solid vertical line 91 delimits the full-load operation (area 1) from the part-load operation (area 2), if in addition the humidification is active. The dashed horizontal line 92 corresponds to the liquefaction set point.

The set speed of the fans 4 set on the drive unit 1 is set as a function of the liquefaction setpoint. Will this

Condenser setpoint not reached due to high ambient temperatures, so the fans 4 run at full speed 41 and the

Heat exchanger 2 is in full load operation. In this

Operating condition follows the liquefaction temperature of

Ambient temperature. If the set condensing setpoint is reached, Thus, the speed 41 of the fans is regulated back to avoid a further decrease in the liquefaction temperature. In the second or third operating mode, the condensing temperature is determined by the

lowered additional wetting of the heat exchanger 2, whereby the demarcation between full load operation (area marked in the diagram with 1) and part load operation (range in the diagram with 2

marked) shifts.

FIG. 4 is a schematic representation of a third embodiment of a heat exchanger 2 with wetting device 3 and a PID controller 10. Fig. 4 corresponds essentially to Fig. 1, which is why only addresses the differences. In this case, the drive unit (not shown) adjusts the wetting device 3 by means of the PI controller 10. The Pl regulator 10 adjusts a control ball valve 12 having an inflow of the

Wetting fluid to the wetting device 3 sets. The

Wetting device 3 is designed as a bead tube, which rests on one or more moistening mats (not shown). One

Water meter 1 1 measures the amount of water of the wetting fluid flowing to the wetting device 3. In addition, a drain valve 13

provided, which empties the wetting device 3, if necessary. A control scheme may be configured such that a set of Pl-controller 10 amount of water or Sprühwassermenge 31 for

Wetting device 3 flows. The water meter 1 1 detects the amount of water and the Pl controller 10 is based on a control deviation, the amount of water to the calculated Sprühwassermenge 31 a.

Claims

Drive unit for a heat exchanger (2), wherein the

Control unit (1) Information about an ambient temperature, an ambient humidity, an amount of water

Wetting device (3) for wetting the heat exchanger (2) and a speed 41 of a fan (4) of the heat exchanger (2) receives, and the drive unit (1) is provided in

Dependence on the information mentioned, one

To calculate amount of spray water (31) and the drive unit (1) the wetting device (3) adjusted so that the

Wetting device (3) wets the heat exchanger (2) with the calculated amount of spray water (31).

Drive unit according to claim 1, wherein the drive unit (1) receives information about a geodetic height and / or the calculated amount of spray water (31) receives an estimated value for a

Represents evaporation amount.

Drive unit according to claim 1 or 2, wherein the drive unit (1) is provided to calculate a cost function in dependence on a parameter and to set the heat exchanger (2) such that the cost function is minimal.

Drive unit according to claim 3, wherein the parameter as

Water price for the wetting device (3) and / or as

Electricity price for the fan (4) is executed.

Drive unit according to one of claims 1 to 4, wherein the

Control unit (1) next to the amount of water spray (31) a

Set speed of the fan (4) sets.

6. Drive unit according to one of the preceding claims, wherein the drive unit (1) adjusts the wetting device (3) by means of a PI controller (10).

7. Heat exchanger comprising a drive unit (1) according to one of claims 1 to 6.

8. Heat exchanger according to claim 7, comprising

a module (5) containing a plurality of transmission elements and a plurality of heat exchange ribs, which are thermally conductively connected to the transmission elements and form an air duct, and a fan (4), wherein the fan (4) in the air duct a

Air flow generated,

wherein a wetting device (3) is arranged on the heat exchanger (2) and the heat exchanger (2) with a

Wetted wetting fluid. 9. Heat exchanger according to claim 7 or 8, wherein a fan (4) associated with the control unit (6) has a target speed of the

Drive unit (1) receives and the control unit (6) to it

is provided to adjust the fan (4) to the target speed.

10. Heat exchanger according to one of claims 7 to 9, wherein the

Wetting device (3) is provided for the module (5), the

To wet transmission elements and / or the heat exchange ribs and / or a moistening mat with liquid.

1 1. Method for controlling a heat exchanger (2), wherein in

Dependence on an ambient temperature, a

Ambient moisture, a quantity of water from a wetting device

(3) for wetting the heat exchanger (2) and a speed 41 of a fan (4) of the heat exchanger (2) a

Amount of spray water (31) is calculated and the Wetting device (3) is set such that the

Heat exchanger (2) with the calculated amount of water spray (31) is wetted.

12. The method of claim 1 1, wherein in a first operating mode, the fan (4) with a maximum target speed and the

Wetting device (3) can be set with a maximum amount of water spray (31).

13. The method of claim 1 1 or 12, wherein in a second

Operation mode, the amount of spray water (31) is calculated such that it represents an estimate for an evaporation amount.

14. The method according to any one of claims 1 1 to 13, wherein in a third mode of operation, a cost function in function of a

Parameter is calculated and the heat exchanger (2) is set so that the cost function is minimal. 15. The method according to any one of claims 1 1 to 14, wherein the

Amount of spray water (31) is calculated as a function of a geodetic height and / or as a function of a

Condensing temperature is derived operating mode of the heat exchanger (2).