WO2010088893A1

WO2010088893A1 - Method and apparatus for cooling and dehumidifying air

Info

Publication number: WO2010088893A1
Application number: PCT/DE2010/000131
Authority: WO
Inventors: Helmut E. Feustel
Original assignee: Hochschule Fuer Technik Und Wirtschaft Berlin
Priority date: 2009-02-05
Filing date: 2010-02-05
Publication date: 2010-08-12
Also published as: EP2394101A1; DE102009007591B3; US20120048954A1

Abstract

The invention relates to a method for air conditioning by way of a ventilation system, wherein, in order to set a specified target air state characterized by air humidity and air temperature, air having an initial air state is cooled and dehumidified with the help of an air cooler (10), in that a coolant supply apparatus assigned to the air cooler (10) for a coolant supplied to the air cooler (10) regulates both a coolant mass flux and a coolant inlet temperature in accordance with the initial air state and the specified target air state. Moreover, an apparatus for air conditioning is provided.

Description

Method and device for air cooling and dehumidification

The invention relates to a method and a device for air cooling and dehumidification.

Background of the invention

Ventilation systems for workplaces and meeting rooms are often used to maintain not only indoor air quality, but also thermal comfort. For this, these systems are usually equipped with system components so that at least three thermodynamic air treatments can be performed: heating, cooling and dehumidifying. The installations must be controlled and controlled in such a way that both objectives (maintenance of indoor air quality and thermal comfort) are achieved, although there may well be varying thermal loads and material loads in the room and for persons in the room an external air mass flow necessary for hygienic reasons must be complied with.

The comfort zone in air-conditioned workplaces is defined in terms of temperature and humidity. For example, in the relevant standard of 2006, DIN EN ISO 7730, the operating temperature for the cooling case for category B office premises is given in a range of 24,5 ⁰ C ± 1,5 K. The DIN EN 13779 of 2007 proposes for the summer for the moisture loading a range between 6 and 12 g / kg.

For reasons of saving energy and reducing operating costs, the room air temperature and the relative humidity should be run over the year according to a setpoint program that provides higher values for room air temperature in summer and higher relative humidity values than in winter. This sliding operation takes into account the seasonal cooling and moisture loads.

The thermodynamics of humid air is called psychrometry. In this case, the air is a gas-vapor mixture in which the component is referred to as vapor, which can condense in the temperature and pressure range under consideration as a liquid or as a solid. The other components are added to the component group "Gas". summarized and remain unchanged for the temperature range considered in their amount.

With the temperature and pressure range available in process and room air technology, moist air can be regarded as a mixture of ideal gases. Since at random temperature not arbitrary amounts of steam mix with the non-condensing gas, three states are distinguished. In the unsaturated state, only the gas phase is present. The partial pressure of the vapor is less than the saturation pressure of the vapor in the mixture. In the saturated state, the partial pressure of the steam is just the saturation pressure of the vapor in the mixture. Gas phase and incipient condensate phase have the same temperature T (thermal equilibrium) and the same total pressure (mechanical equilibrium). In the supersaturated state gas and condensate phase are present. In the gas phase, the relations of the saturated state apply.

Various diagrams are used to represent the humid air states and state changes. The best-known diagrams are the Mollier diagram (Europe) and the carrier diagram (America). In Mollier the enthalpy (hi _{+ x} ) of the mixture is chosen as the ordinate and the moisture loading x as the abscissa. The enthalpy depends linearly on the temperature for the unsaturated region as well as for the supersaturated region. 1 shows a schematic representation of a simplified Mollierdi- agramms for a given total pressure.

The cooling and dehumidification of the air in central ventilation systems is usually carried out by means of air cooler, which are flowed through by a coolant. The power control takes place either on the air side or on the coolant side by means of a suitable hydraulic circuit. In the case of hydraulic power control, which is usually realized by changing the coolant flow at a constant coolant flow temperature (volume-controlled cooling). Less commonly used is a control method known from heating technology, in which the coolant flow temperature is regulated by means of admixture from the coolant return (mixture-controlled cooling).

There are two different hydraulic circuits for the hydraulic control of the cooling power, which also different state changes of the air at the cause the heat exchanger (air cooler) to flow. It is on the one hand a system in which the air cooler is provided with a volume control. At constant coolant flow temperature, the amount of coolant supplied to the air cooler is regulated. On the other hand, systems are known in which the air cooler is provided with an admixing control. Here, the flow temperature of the coolant fed into the air cooler is controlled.

In the case of a volume-controlled air cooler, dehumidification always takes place in the case of a water vapor charge above a limit, which depends inter alia on the flow temperature of the coolant, since the coolant flow temperature, independent of the building cooling load, can be assumed to be constant (cf. 2, route 1 - 4). As a result, the surface temperature of the air cooler at the coolant inlet is close to the chilled water supply temperature provided by the refrigerator. In general, this flow temperature is in conventional systems at about 6 ⁰ C. The end point of the change in state of the mixed partial flows of air is theoretically on the connecting line between the state point of the air flow upstream of the radiator (point 1 in Fig. 2) and the effective surface temperature of the Air cooler (point to _{, eff} in Fig. 2). The slope of the state change in the Mollier diagram for a given radiator design for each starting point of the humid air thus depends only on the starting point itself and on the effective surface temperature of the air cooler (point to _{, e} ff in Fig. 2).

It can be distinguished in this known circuit type between two modes. Either, the desired degree of dehumidification determines the air outlet temperature from the air cooler, or, the necessary cooling determines the degree of dehumidification of the air. The desired end point for temperature and humidity can therefore not be precisely adjusted with the air cooler alone. To achieve a fixed air condition, the air flow to the air cooler must therefore be either heated (dehumidification determines the cooling), or the air flow must be moistened (cooling determines the dehumidification).

With a derischgeregelten air cooler, an air flow is completely cooled without dehumidification, if the inlet temperature of the cooling medium in the air cooler does not fall below the dew point temperature of the humid air (see Fig. 2, track 1 - 2). Only when the coolant flow temperature due to throttling the Kühlmittelrücklaufbeimischung below the Dew point temperature of the moist air is a condensation of water vapor, ie a dehumidification, for a partial air flow (see Fig. 2, route 2 - 3).

Ideally, with infinite coolant mass flow, the entire air mass flow has to be cooled down to the dew point before the dehumidification process actually starts. If, according to this concept, steam is condensed from the air mass flow, then the entire amount of air must be cooled down to the dew point of the desired moisture loading, which generally results in subcooling of the air mass flow and is therefore unfavorable in terms of energy (compare FIG. 2, points 3 and 4). The necessary heating of the supercooled air mass flow requires additional energy, whereby the economy of a mixed-controlled cooler continues to deteriorate.

Each of the two known circuits changes the capacity control of the air cooler exactly one size of the coolant flow. In the quantity-controlled circuit, the mass flow (the quantity) is regulated. In the mixed-control circuit, the coolant flow temperature is controlled according to the performance requirements. To achieve a desired air condition with respect to temperature and water vapor loading both known circuits have advantages and disadvantages. In the case of the volume-controlled air cooler, depending on the desired air condition, either a reheating of the air flow may be necessary, or an air humidification. In the case of a dehumidification case, the mixture-controlled air cooler must almost always be cooled lower than the cooling load requires. The operation of an air reheater is therefore imperative to obtain the desired air condition.

Summary of the invention

The object of the invention is to provide a method and a device for air cooling and dehumidification by means of an air conditioning system, which enables a targeted and energy-efficient adjustment of a target air condition characterized by air humidity and air temperature.

This object is achieved by a method for air cooling and dehumidification according to the independent claim 1 and a device for Luftkonditio- nierung according to independent claim 7. Advantageous embodiments of the invention are the subject of dependent subclaims.

According to one aspect of the invention, there is provided a method of air cooling and dehumidification by means of an air conditioning system wherein air is controlled with an initial air condition by means of an air cooler and optionally dehumidified to set a predetermined target air condition characterized by humidity and air temperature, by a coolant supply associated with the air cooler for a coolant supplied to the air cooler, both a coolant mass flow and a coolant inlet temperature are regulated in accordance with the outlet air state and the predetermined target air state.

According to a further aspect of the invention there is provided an apparatus for air cooling and dehumidification comprising: an air cooler configured to cool and optionally dehumidify air having an outlet air condition to set a predetermined target air condition characterized by air humidity and air temperature; and a coolant supply device for a coolant to be supplied to the air cooler, which is configured to regulate both a coolant mass flow and a coolant inlet temperature according to the output air state and the predetermined target air state.

The proposed techniques are used for air conditioning, in particular room air conditioning.

Air coolers with conventional hydraulic circuits are only partially able to set desired air conditions in the case of cooling. Known quantity-controlled air coolers are e eergetic then inefficient, if the desired cooling capacity leads to an unnecessarily high dehumidification performance. On the other hand, mixing-controlled air coolers always waste cooling energy when dehumidification is necessary in addition to the pure cooling capacity. With the invention, these disadvantages are now overcome. In the proposed method and in the device a precise control of air cooling and - dehumidification is made in the Kühlmittezuführeinrichtung. Both the quantity and the inlet temperature of the coolant for the air cooler are included in the coolant supply. guiding device regulated. This allows energy-efficient manner a precise adjustment of a desired Zielluftzustandes.

A preferred development of the invention provides that the regulation of the coolant mass flow and the coolant inlet temperature is carried out with the aid of a hydraulic circuit of the coolant supply device.

In an expedient embodiment of the invention, it can be provided that the regulation of the coolant mass flow and the coolant inlet temperature is carried out with the aid of an integrated control circuit comprised of the coolant supply device, in which a mixture-controlled circuit is formed with a delivery-controlled pump device. In this embodiment, an integrated control circuit is formed, which represents an integration of the mixing-controlled circuit and the quantity-controlled circuit. The coolant supplied to the air cooler is determined with respect to the quantity (coolant mass flow) by the delivery-regulated pump and with respect to the temperature by the coolant return admixture.

An advantageous embodiment of the invention provides that the regulation of the coolant mass flow and the coolant inlet temperature is carried out with the aid of a series connection of a mixture-controlled and a quantity-controlled circuit encompassed by the coolant supply device. It can be provided that the coolant supply device consists only of the mixing-controlled and the quantity-controlled circuit.

In one embodiment of the invention, it can be provided that the regulation of the coolant mass flow and the coolant inlet temperature is carried out with the aid of an integrated control circuit comprising the coolant supply device, in which a pump device with constant delivery pressure and a valve control device are formed.

An embodiment of the invention provides that the regulation of the coolant mass flow and the coolant inlet temperature is carried out with the aid of an integrated control circuit comprised of the coolant supply device, in which a pump device with constant rotational speed and a bypass device are formed. The bypass device preferably comprises a regulated bypass. Description of preferred embodiments of the invention

The invention will be explained in more detail below with reference to embodiments with reference to figures of the drawing. Hereby show:

1 is a schematic representation of a known Mollier diagram for a given total pressure,

Fig. 2 is a schematic representation of the known change in state of humid air in

3 is a schematic representation of a device for air cooling and dehumidification with an integrated hydraulic circuit consisting of a derischgeregelten circuit with a direct flow rate controlled pumping device,

4 is a schematic representation of a device for air cooling and dehumidification with an integrated hydraulic circuit consisting of a derischge- regulated circuit with an indirectly flow rate controlled pumping device,

5 is a schematic representation of a device for air cooling and dehumidification with an integrated hydraulic circuit consisting of a derischgeregelten circuit with an unregulated pumping device with controlled bypass,

6 is a schematic representation of a device for air cooling and dehumidification with an integrated hydraulic circuit consisting of a series circuit of derischgeregelter circuit with unregulated pumping device and a volume-controlled circuit,

7 shows symbols for elements of the analagenic scheme in FIGS. 3 to 6 and FIG. 8, FIG.

8 is a simplified system diagram of an air-only system with heat recovery and recirculation path, wherein a humidification using a steam humidifier,

9 shows a schematic representation of a control strategy for the devices for air cooling and dehumidification in FIGS. 3 to 6 in the simplified Mollier diagram;

10 is a simplified control diagram for the hydraulic circuit according to FIG. 3; FIG. 11 is another simplified control diagram for the hydraulic circuit according to FIG. 3;

12 is another simplified control diagram for the hydraulic circuit of FIG. 3,

13 is another simplified control diagram for the hydraulic circuit of FIG. 3, and 14 shows a further simplified control diagram for the hydraulic circuit according to FIG. 3.

3 shows a schematic representation of a device for air conditioning (cooling and dehumidification) with an integrated control circuit, in which a delivery-controlled pumping device is integrated into a delivery-controlled circuit. The integrated circuit is executed in the illustrated embodiment as a hydraulic circuit, which can also be referred to as "Optimized Dehumidification Control Loop" (OpDeCoLo), they the targeted adjustment of a characterized by humidity and air temperature Zielluftzustandes using a liquid-cooled air cooler with the least possible energy use (cooling and conveying energy) allows.

In the device in Fig. 3, a coolant supply device 11 is coupled to an air cooler 10, which is formed with a mixing valve 12 and a speed-controlled pump 13. The mixing valve 12 connects a chilled water supply 14 provided by a refrigerator (not shown) with the admixture of a coolant return 15 for the coolant supply 16 to be fed into the air cooler 10 with the desired temperature and quantity. The state of the air emerging from the air cooler 10 becomes detected by a temperature measuring device 17 and a humidity measuring device 18.

The circuit in Fig. 3 corresponds to the derischgeregelten circuit, but in which instead of a pump with a constant flow rate, the variable-speed pump 13 is installed. The mixing valve 12, which defines three ways, is provided with an actuator 19.

The speed control of the variable-speed pump 13 (see Fig. 3) can be done by means of a frequency converter (not shown). In the case of a desired dry cooling, the air cooler 10 and the coolant mass flow are designed so that the cooling capacity is provided with a coolant inlet temperature above the respective dew point of the moist air. In many cases, this requires a larger-sized air cooler than in the case of a volume-controlled hydraulic circuit or a derischgeregelten circuit with humid cooling.

Alternatively, a pump 40 with constant delivery pressure together and a controlled passage valve 41 (see Fig. 4) or a pump 50 with constant speed with a bypass 51 (see Fig. 5) may be provided, which is preferably carried out regulated. Expressed in simple terms, the dehumidification of the air is determined by selecting the cooling water inlet temperature, the cooling capacity, however, by means of the coolant mass flow. The respective total cooling power from cooling and dehumidification of the air cooler 10 thus results as a combination of coolant mass flow and coolant inlet temperature.

State changes can be achieved with the proposed circuits, which in another embodiment can also be realized with a series connection of a quantity-controlled and a mixed-mode circuit component (compare FIG. 6), but with significantly lower energy consumption. Fig. 6 shows a schematic representation of an apparatus for air conditioning (cooling and dehumidification) with an integrated control circuit consisting of a series circuit of derischgeregelter circuit 60 with non-flow rate controlled pumping device 61 and a quantity-controlled circuit 62. For the same features in Fig. 6, the same reference numerals as used in Figs. 3-5.

In terms of energy, the volume-controlled air cooler is much more efficient in the case of desired dehumidification than the mixed-air cooler. The savings potential for the device for air conditioning according to FIGS. 3 to 6 compared with the known volume-controlled air cooler is obtained in particular for the following cases:

- For all output air conditions that require cooling and their moisture content below the maximum moisture content in the target state, for example, for comfort reasons, and whose dew point is above the coolant inlet temperature of a conventional volume-controlled hydraulic circuit. Especially in this area, which does not require dehumidification for reasons of comfort, a demischgeregelter air cooler would be energetically cheaper than a volume-controlled air cooler.

- For outlet air conditions whose moisture load is above the maximum air humidity in the target air condition. Here is the distance of the humidity loading of the outlet air condition from the maximum permissible humidity load and the temperature of the target area for the

Savings potential crucial. Output air conditions with a high air temperature but low dehumidification load usually lead to excessive dehumidification in the case of volume-controlled switching. In contrast, starting conditions with high moisture content with only a slight temperature difference to the target area in all hydraulic circuits to a supercooling of the air mass flow, which is to be compensated by reheating.

The effects of the hydraulic circuit of the air cooler on the specific cooling energy requirements for a ventilation system are examined below.

For the comparison, an air-only system (see Fig. 8) with a recuperative heat recovery and a recirculation control (Economϊzer Mode) was selected. The savings potential of the device for air conditioning according to FIG. 3 is related to both the mixture-controlled and the quantity-controlled air cooler. The energy requirement, which may be required for reheating or moistening, is not considered in this comparison for the sake of simplification, which reduces the calculated potential for savings compared with the real case.

An air-only system with regenerative heat recovery (WRG) and a recirculation damper control corresponds to the state of the art for ventilation systems that have to dissipate high thermal loads with changing occupancy. For this comparison, a recirculation system was selected for heat recovery, which can be easily bridged if necessary by switching off the pump and, in addition, offers the possibility of being able to conduct outside air and exhaust air flow in separate locations. Existing plants are often retrofitted with such systems.

Table 1: Boundary conditions for determining the energy requirement for air cooling as a function of the hydraulic circuit of the air cooler

The ventilation system should be operated in such a way that the heat recovery system is only active for the summer, when the temperature of the outside air (ODA) exceeds that of the exhaust air (EHA). The pretreated outside air (PODA) after WRG is mixed in the mixing chamber only recirculated air (RCA), if the circulating air has a lower temperature than the pretreated outside air flow (PODA). The moisture content of the circulating air was assumed to be 1 g / kg higher than that of the outside air due to humidity sources in the room. The boundary conditions of the comparison are shown in Table 1.

The recirculating air admixture not only reduces the temperature reduction to be provided by the air cooler, but also reduces the difference between the moisture content of the outside air and the set point after the air cooler.

The calculation of the air conditions that occur after the air cooler is based on simplified approaches. For the derischgeregelten air cooler, it was assumed that the

Cooling process until the dew point temperature is reached without condensate failure. In the case of further cooling, the state change follows the saturation line. In the case of the volume-controlled air cooler, it was assumed that the state change in each case on a straight line between the starting point and one of the effective surface temperature of the radiator to. _rms proportional temperature. The device for air conditioning according to FIG. 3 produces a combination of both types of circuit, wherein in the boundary region there is either a mixture-controlled or a quantity-controlled cooler.

Fig. 7 shows symbols for elements of the plant scheme in Figs. 3 to 6 and Fig. 8. Here, an air-only system with heat recovery and recirculation path is shown in simplified, wherein a humidification by means of a steam humidifier.

Although FIG. 8 shows a complete air-only installation, only the cooling energy requirement (air cooling and dehumidification) is included in the estimation of the energy-saving potential. Neither Reheating or humidification are considered in this comparison. Also not included were the energy costs for operating the pumps. Again, the hydraulic circuit shown in Fig. 3 cuts off better than the two base circuits and the circuits of Figs. 4 to 6.

For the present type of installation, the cooling energy requirement for three hydraulic circuits for different German climates was investigated. For this purpose, statistical weather data according to DIN 4710 of 2003 were selected for the outdoor air values and the annual specific cooling energy demand compared. The following summarizes the results for Mannheim (see Table 2).

Table 2: Specific annual cooling energy requirement for a mass air flow of 1 kg / h for climatic data for Mannheim

The assumptions made for the boundary conditions clearly show the superiority of the OpDeCoLo over the conventional circuits, because only dehumidification is required if this is really necessary for reasons of comfort.

To achieve the savings potential, a speed-controlled pump is used on the hardware side in one of the embodiments described above. The concept of an associated control technology that not only the coolant mass flow or the coolant inlet temperature, but also the respective optimum of coolant inlet temperature and coolant telematic power is shown below. The speed control of the pump can be carried out either by means of a frequency converter (see FIG. 3) or, as shown in FIG. 4, by means of a change in the flow resistance with the aid of a valve. The hydraulic circuits of Fig. 5 and Fig. 6 with unregulated pumping devices are also able to achieve the cooling energy savings according to Table 2, but are characterized by higher delivery costs.

9 shows a schematic representation of a control strategy for the air coolers described above in the simplified Mollier diagram. Unlike conventional control circuits of air coolers, both the coolant quantity and its inlet temperature are always regulated in the circuits proposed here.

The control concept is described in more detail below.

When cooling without dehumidification, the surface temperature of the cooler must never be equal to or lower than the dew point temperature of the moist air to be cooled. Therefore, in this case, the flow temperature of the cooling fluid for the air cooler must not fall below the dew point temperature of the moist air. Since the cooling capacity depends on the average surface temperature of the air cooler, the air can not be cooled down to the saturation line. Therefore, in this case, the air cooler is operated at a high pump speed, the power adjustment being done by changing the refrigerant return admixture.

On the coolant side:

-A'uft / en ^{= m} Coolant * ^C p _kuhhmlκ ι * K RucklauJ ^~ 'flow) CU with

Qκ _«Men cooling capacity of the air cooler [W]

^ ¹ _KuMmI i _W i Coolant _mass flow [kg / s] c _pKuMm iii _c i specific heat capacity of the coolant [kJ / (kg * K)] V i _tuckhuf ~ ^ _or i _{au /} ) temperature difference of the coolant before and after the air cooler [K] and t _Vrιr ι _auj ≥ t _urba

On the air side, the cooling capacity is determined according to equation (3) with the aid of equation (2):

M _Kuhk A ^x x * ( ^r o + S _D * ^f i) ^{+ c} _PL * O-Uκ * (> O + ^ * t _LK ) + c _pL * t _LK ) (2)

With

ro Heat of evaporation of water at O ⁰ C [kJ / kg]

C _pD specific heat capacity of water vapor [kJ / (kg * K)]

C _pL specific heat capacity of dry air [kJ / (kg * K)]

Qκ _mills = ^"1 M * M _kmen (3)

m _lufi air mass flow [kg / s] Δh _KMm enthalpy _difference ; here at constant humidity loading of the air [kJ / kg]

In cooling with dehumidification, in addition to the air outlet temperature from the radiator, the water vapor loading of the air is regulated. For this purpose, both the pump speed and the coolant return admixture are changed so that the target point of the air is achieved at the radiator outlet. Here, the flow rate (pump speed), the flow rate control and the coolant inlet temperature (coolant return admixture) takes over the admixing. Expressed in very simplified terms, the delivery mass flow at constant coolant temperature determines the slope of the state change in the Mollier diagram; At constant flow, the coolant inlet temperature determines the sensible cooling capacity. However, the two parameters are not independent of each other because the effective surface temperature also changes due to the influence on the coolant return temperature as the coolant inlet temperature and the mass flow rate changes both has an influence on the sensitive cooling performance and the dehumidification of the airflow. For a given outlet air condition, depending on the initial condition, there is a combination of mass flow rate and inlet temperature.

10 to 14 simplified control diagrams for the hydraulic circuit of FIG. 3. The letters "R" and "N" denote a Rücklaufbeimischung and a Pumpendrehzahlschal-. Arrows indicated in conjunction with these control variables indicate a regulation for enlargement (arrow up) or for reduction (arrow down) of the respective size. The variables T _so n and Tj _St denote a setpoint and an actual temperature of the cooled / dehumidified air. In the same way _as X denote n and Xj _st designate a target and an actual air humidity. The numerals "11", "21", ... serve to refer between the control schemes in FIGS. 10 to 14.

The features of the invention disclosed in the above description, the claims and the drawing may be of significance both individually and in any combination for the realization of the invention in its various embodiments.

Claims

claims

1. A method for air conditioning by means of an air conditioning system, wherein for setting a characterized by humidity and air temperature predetermined target air condition air with an outlet air condition using an air cooler (10) is cooled and dehumidified by the air cooler (10) associated with a coolant supply for a Coolant (10) supplied coolant controls both a coolant mass flow and a coolant inlet temperature according to the outlet air condition and the predetermined target air condition.

2. The method according to claim 1, characterized in that the regulation of the coolant mass flow and the coolant inlet temperature by means of a hydraulic circuit of the coolant supply device is performed.

3. The method of claim 1 or 2, characterized in that the rules of the coolant mass flow and the coolant inlet temperature is carried out by means of an integrated from the coolant supply, integrated control circuit, in which a derischgeregelte circuit with a flow rate controlled pumping device (13) is formed.

4. The method according to claim 1 or 2, characterized in that the regulation of the coolant mass flow and the coolant inlet temperature by means of one of the Kühlmittelzuführeinrichtung included series connection of a derischgeregelten and a quantity-controlled circuit (60, 62) is executed.

5. The method according to claim 1 or 2, characterized in that the regulation of the coolant mass flow and the coolant inlet temperature is carried out by means of an integrated by the coolant supply, integrated control circuit, in which a pumping device (40) with constant delivery pressure and a Ventilregeleinrich- device (41 ) are formed.

6. The method according to claim 1 or 2, characterized in that the regulation of the coolant mass flow and the coolant inlet temperature by means of one of the Coolant supply means included, integrated control circuit is executed, in which a pump device (50) is formed at a constant speed and a bypass device (51).

7. Apparatus for air conditioning, comprising:

an air cooler (10) configured to cool and dehumidify air having an outlet air condition to set a predetermined target air condition characterized by humidity and air temperature, and

a coolant supply means connected to the air cooler for a coolant to be supplied to the air cooler, which is configured to control both a coolant mass flow and a coolant inlet temperature according to the output air state and the predetermined target air state.

8. The device according to claim 7, characterized in that the coolant supply device is formed with a hydraulic circuit, which is configured, the

To regulate the coolant mass flow and the coolant inlet temperature.

9. Apparatus according to claim 7 or 8, characterized in that the coolant supply device is designed with an integrated control circuit, in which a derischgeregelte circuit is formed with a flow rate controlled pumping device and which is configured to control the coolant mass flow and the coolant inlet temperature.

10. Apparatus according to claim 7 or 8, characterized in that the Kühlmit- telzuführeinrichtung is carried out with a series circuit in which a derischgeregelte and a quantity-controlled circuit are connected in series.