DE102016106046A1 - DEC air conditioning system for air conditioning of a room and method for air conditioning a room - Google Patents

Abstract

The present invention relates to a DEC air conditioner for air conditioning of a room, with a Zuluftpfad, via which cooled outside air from the intake air is provided for the room, and an exhaust path, via which exhaust air of the room can be discharged as exhaust air to the environment, with a sorption , via which of the outside air in the supply air path moisture can be withdrawn and this moisture can be delivered to the exhaust air in the exhaust air path, with a heat recovery unit, over which the dehumidified in the sorption dehumidified outdoor air in the supply air heat is withdrawn and this heat can be delivered to the exhaust air in the exhaust path, with a Zuluftbefeuchter over which exiting the heat recovery unit outside air is moistened to cool the outside air by evaporation, wherein in the supply air path between the heat recovery unit and the Zuluftbefeuchter a supply air heat exchanger is arranged, the Zuluft Wärmeübertra ger is connected to a cooling device, via which the supply air heat exchanger, a cooled cooling fluid for additional cooling of the exiting the heat recovery unit outside air is zuleitbar.

Description

State of the art

The present invention relates to a DEC air conditioner for air conditioning of a room, with a Zuluftpfad, via which cooled outside air from the intake air is provided for the room, and an exhaust path, via which exhaust air of the room can be discharged as exhaust air to the environment, with a sorption , via which of the outside air in the supply air path moisture can be withdrawn and this moisture can be delivered to the exhaust air in the exhaust air path, with a heat recovery unit, over which the dehumidified in the sorption dehumidified outdoor air in the supply air heat is withdrawn and this heat can be delivered to the exhaust air in the exhaust path, with a Supply air humidifier, via which the outside air exiting the heat recovery unit is moistened to cool the outside air by evaporation. Furthermore, the invention relates to a method for air conditioning of a room, being provided via a Zuluftpfad from sucked outside air cooled supply air for the room and is discharged via an exhaust air exhaust air of the room as exhaust air to the environment.

Various technologies are available for air conditioning of rooms. Air conditioners based on compression refrigerators are widely used. Such conventional air conditioners have a comparatively low energy efficiency. As an alternative to air conditioning systems based on compression refrigeration machines, DEC air conditioners (English: Desiccative and Evaporative Cooling) have proven themselves. These DEC air conditioners are not operated with a conventional refrigerant circuit, but allow the cooling of supply air through an evaporation process.

A typical DEC air conditioning system has a supply air path and an exhaust air path. The fresh air supplied to the supply air path is first dried and heated in a sorption device. The moisture extracted from the outside air is released to the exhaust air in the exhaust air path. In a subsequent step, the supply air flows through a heat recovery unit. In the heat recovery unit, heat is removed from the outside air in the supply air path. This heat is released to the exhaust air in the exhaust path. Before the thus dehumidified and cooled outside air is added to the room as supply air, the outside air passes through a Zuluftbefeuchter, in which further cooling by evaporation takes place to set the desired supply air temperature.

The cooling capacity that can be provided by such DEC air conditioners is limited by the evaporation process. This has the consequence that such rooms, which are temporarily exposed to strong sunlight, can not always be satisfactorily air-conditioned.

Disclosure of the invention

Against this background, it is an object of the present invention to enable air conditioning even with strong solar radiation.

The object is achieved by a DEC air conditioning system for air conditioning of a room, with a Zuluftpfad, which is provided by sucked outside air cooled supply air for the room, and an exhaust air path, via which exhaust air of the room can be discharged as exhaust air to the environment, with a Sorption, over which of the outside air in the supply air moisture can be withdrawn and this moisture to the exhaust air in the exhaust air path can be issued, with a heat recovery unit through which the dehumidified in the sorption dehumidified outdoor air in the supply air heat is withdrawn and this heat can be delivered to the exhaust air in the exhaust path, with a Zuluftbefeuchter over which exiting the heat recovery unit outside air is moistened to cool the outside air by evaporation, wherein in the Zuluftpfad between the heat recovery unit and Zuluftbefeuchter a supply air heat exchanger is arranged, wherein the supply air heat exchanger is connected to a cooling device, via which the supply air heat exchanger, a cooled cooling fluid for additional cooling of the exiting the heat recovery unit outside air is zuleitbar.

Compared to the known from the prior art DEC air conditioning systems, there is the advantage that the supply air can be additionally cooled by means of the supply air heat exchanger, if necessary. The supply air heat exchanger is arranged in the supply air path between the heat recovery unit and the Zuluftbefeuchter, so that an adjustment of the sorption and / or the heat recovery unit is not required. The dehumidified and cooled outside air may be provided to the supply air humidifier at a temperature reduced from the prior art. In this respect, a peak load refrigeration system is provided via the supply air heat exchanger, which can be activated if necessary in strong sunlight to cool the supply air to a lower temperature.

A preferred embodiment provides that the cooling device is designed as a magnetocaloric cooling device. A magnetocaloric cooling device is based on the magnetocaloric effect, according to which a magnetocaloric material heats up when a magnetic field is applied and cools when the magnetic field is removed. In In the case of a magnetocaloric cooling device, a cooling effect can be achieved by periodically magnetizing the magnetocaloric material and dissipating the resulting heat by means of the cooling fluid, for example via a heat exchanger. Compared to refrigerators, with a compression refrigeration machine, magnetocaloric refrigerators have up to 30% higher efficiency. The increased efficiency can be attributed in particular to the fact that a magnetocaloric cooling device can have a reduced number of moving parts.

According to an alternative, preferred embodiment, the cooling device is designed as a heat pump, in particular with a compression refrigeration machine. Even if the efficiency achievable with such a heat pump is not as high as in a configuration with a magnetocaloric cooling device, the use of a heat pump as a cooling device offers the advantage that a greater cooling capacity can be achieved.

It has proven to be advantageous embodiment in which the DEC air conditioning system has a photovoltaic system, via which the cooling device can be supplied with electrical energy. As a result, the additional cooling of the supply air can be done with energy from a regenerative source. In addition, results from the use of a photovoltaic system for providing electrical energy for the cooling device, the advantage that, if due to increased sunlight unwanted heating of the room to be conditioned is to be feared, additional electrical energy to operate the cooling device and thus for additional cooling the supply air is available. In this respect, the DEC air conditioning can be formed with a solar radiation-dependent activatable cooling unit without additional devices for detecting the solar radiation and for activating the cooling device are required.

In this connection, it is preferable if the DEC air conditioner is configured without a device for activating and / or controlling the cooling device. The cooling device can automatically go into operation when electrical energy is provided by the photovoltaic system, so that an automatically controlling peak load refrigeration system is made possible. An elaborate control unit for activating and / or switching off and / or controlling the peak load refrigeration system can be dispensed with. In an embodiment in which a magnetocaloric cooling device is supplied via the photovoltaic system, a self-sufficient peak-load refrigeration system can be provided. Because due to the increased efficiency of the magnetocaloric cooling device, the power supply of the cooling device can be done completely by the photovoltaic system, so that no externally supplied, electrical energy is required. The electrical energy generated in the photovoltaic system can be used locally to operate the cooling device, so that a connection of the photovoltaic system to a public power grid is not required.

Preferably, the, in particular magnetocaloric, cooling device has a first output for discharging the cooled cooling fluid, a so-called cold side, and a second outlet for emitting a heated cooling fluid, a so-called warm side. The heat removed from the cooled cooling fluid can be removed from the cooling device via the hot side. The dissipated heat can be advantageously used for the regeneration of the sorption.

The DEC air conditioning system preferably has an exhaust air heat exchanger arranged in the exhaust air path, which is connected to the cooling device, via which a heated cooling fluid can be supplied to the exhaust air heat exchanger for additional heating of the already heated exhaust air emitted by the heat recovery unit. The exhaust air heat exchanger can take over the function of a reheater in the exhaust path, through which the exhaust air supplied to the sorption can be additionally heated.

In this context, it is advantageous if the exhaust air heat exchanger is arranged in the exhaust path between the heat recovery unit and the sorption, so that in the heat recovery unit already heated by the heat exchange with the outside air of the Zuluftpfads exhaust air before moistening in the sorption on one for the Sorption process in the sorption suitable temperature can be preheated.

Preferably, an exhaust air humidifier for humidifying the exhaust air of the room is arranged in the exhaust air path. In the exhaust air humidifier, the exhaust air can be humidified adiabatically, in particular, to cool it.

• – Entziehen von Feuchtigkeit aus der Außenluft im Zuluftpfad und Abgeben dieser Feuchtigkeit an die Abluft im Abluftpfad,
• – Entziehen von Wärme aus der bereits entfeuchteten Außenluft im Zuluftpfad und Abgeben dieser Wärme an die Abluft im Abluftpfad mittels einer Wärmerückgewinnungseinheit,
• – Kühlung der aus der Wärmerückgewinnungseinheit austretenden Außenluft mittels eines Zuluft-Wärmeübertragers, wobei der Zuluft-Wärmeübertrager mit einer Kühlvorrichtung verbunden ist, über welche dem Zuluft-Wärmeübertrager ein gekühltes Kühlfluid zur zusätzlichen Kühlung der aus der Wärmerückgewinnungseinheit austretenden Außenluft zugeleitet wird, und
• – Befeuchten der gekühlten Außenluft im Zuluftpfad, um die Außenluft durch Verdunstung zu kühlen.

The object mentioned at the outset is also achieved by a method for air-conditioning a room, supply air being supplied to the room via a supply air path from drawn-in outside air, and exhaust air from the room being discharged via an exhaust air path to the environment as exhaust air, with the following method steps:

• Removing moisture from the outside air in the supply air path and discharging this moisture to the exhaust air in the exhaust air path,
• - Removal of heat from the already dehumidified outside air in Zuluftpfad and delivering this heat to the exhaust air in the exhaust path by means of a heat recovery unit,
• Cooling the exiting from the heat recovery unit outside air by means of a supply air heat exchanger, wherein the supply air heat exchanger is connected to a cooling device through which the supply air heat exchanger, a cooled cooling fluid for additional cooling of the exiting the heat recovery unit outside air is supplied, and
• - Humidifying the cooled outside air in the supply air path to cool the outside air by evaporation.

In the method for air conditioning a room, the same advantages as they have already been described in connection with the inventive DEC Klimaanalage.

Preferably, the cooling by means of the supply air heat exchanger takes place only when the room to be air-conditioned is exposed to an increased thermal load, in particular increased solar radiation. This can be achieved in an advantageous manner in that the cooling device is supplied with electrical energy via a solar radiation-dependent energy source, for example a photovoltaic system.

According to a preferred embodiment, the, in particular magnetocaloric, cooling device is provided via a photovoltaic system electrical energy. It is particularly preferred if there is no active switching on, switching off and / or controlling the, in particular magnetocaloric, cooling device. The, in particular magnetocaloric, cooling device can be permanently connected to the photovoltaic system, so that cooling by the cooling device takes place only when electrical energy is provided by the photovoltaic system, which is usually the case when a certain amount of solar radiation is given.

In addition to the advantageous embodiments of the method described above, the advantageous features described in connection with the DEC air conditioning system can be used alone or in combination in the method for the air conditioning of a room. In particular, as already mentioned above, the supply air heat exchanger can be connected to a magnetocaloric cooling device so that the cooling in the supply air heat exchanger can take place with increased energy efficiency.

Further details, features and advantages of the invention will become apparent from the drawings, as well as from the following description of a preferred embodiment with reference to the drawings. The drawings illustrate only an exemplary embodiment of the invention, which does not limit the inventive concept.

Brief description of the figures

The 1 shows a DEC air conditioning system according to the prior art in a block diagram.

The 2 shows a hx diagram of the DEC air conditioner 1 ,

The 3 shows a DEC air conditioning according to an embodiment of the invention in a block diagram.

The 4 shows a hx diagram of the DEC air conditioner 3 ,

The 5 shows the in 4 Dashed section of the hx diagram in an enlarged view.

Embodiments of the invention

In the 1 is a block diagram of a DEC air conditioner 100 represented according to the prior art. The DEC air conditioning 100 has a supply air path 101 on, from which sucked outside air AU cooled supply air ZU for a room 102 is available. Another part of the DEC air conditioning 100 is an exhaust air path 103 , above the exhaust AB of the room 102 as exhaust air FO is deliverable to the environment.

The DEC air conditioning 100 has a conveyor designed as a fan 104 on, sucked on which outside air AU and a sorption 105 is supplied. The sorption device 105 takes air from both the supply air path 101 as well as on the exhaust air path 103 on to an exchange of moisture between the two paths 101 . 103 to enable. The sorption device 105 is designed as a sorption regenerator. The sorption regenerator has a sorption rotor, which comprises a plurality of air channels. The surface is coated with hygroscopic material, such as silica gel, a zeolite or lithium chloride. The sorption rotor rotates continuously, alternating between the air in the supply air path 101 and the air in the exhaust air path 103 flows through. The outside air AU to be dehumidified enters the sorption device 105 one. The moisture contained in the outside air AU is bound by the hygroscopic material of the sorbent rotor, so that the outside air AU is dehumidified. The hygroscopic material is then regenerated in the exhaust air stream. It takes the relatively warm, the sorption 105 supplied air of the exhaust air path 103 Moisture from the sorption on.

Furthermore, the DEC-Klimaanalage 100 a heat recovery unit 106 on, which is designed as a rotary heat exchanger. The heat recovery unit 106 takes air from the supply air path 101 and from the exhaust air path 103 on to an exchange of heat between the two paths 101 . 103 to enable. The heat recovery unit 106 includes a rotating storage mass, which alternately through the air of the supply air path 101 and the air of the exhaust air path 103 is rotated, allowing a heat transfer between the paths 101 . 103 can take place.

Further, in the supply air path 101 a supply humidifier 107 provided over which the heat recovery unit 106 exiting outside air is moistened to cool the outside air by evaporation. About the supply humidifier 107 will be the desired temperature of the supply air to the room 102 set. The supply air humidifier 107 is designed as an adiabatic humidifier. Adiabatic humidification humidifies the air without supplying energy, ie under adiabatic conditions. The water is atomized and absorbed by the air. The heat required for evaporation is taken from the air, which cools as a result.

The exhaust air path 103 has an exhaust humidifier 108 for moistening the exhaust air of the room. The exhaust humidifier 108 is designed as an adiabatic humidifier.

In addition, in the exhaust air path 103 between the heat recovery unit 106 and the sorption device 105 an exhaust air heat exchanger 109 arranged over which the sorption device 105 supplied exhaust air is heated.

2 shows an hx diagram in which the specific enthalpy h is plotted against the humidity x. The curve φ = 1 separates the unsaturated area above the curve from the saturated area ("fog area") below the curve. The in the 2 points shown 1 to 11 correspond with the corresponding designations of the air flows in 1 ,

It can be seen that the outside air AU in the sorption device 105 ie the transition between the points 2 and 3 , dehumidified and heated. In the next step in the heat recovery unit 106 ie the transition between the points 3 and 4 , there is a cooling of the air in the supply air path. Finally, the air in the supply humidifier 107 moistened and cooled, cf. the transition between the points 4 and 5 ,

The exhaust air AB of the room 102 is in the exhaust humidifier 108 moisturizes and cools, as is the transition between the points 6 and 7 can be seen. In the subsequent process step in the heat recovery unit 106 becomes the air of the exhaust air path 103 heated, cf. Transition between the points 7 and 8th , This is followed by further heating in the exhaust air heat exchanger 109 , see. Transition between the points 8th and 9 , Finally, the air of the exhaust air path 103 in the sorption device 105 moistened and cooled, cf. Step by step 9 to point 10 , and then discharged as exhaust air FO to the environment.

In the 3 is an embodiment of a DEC air conditioning 200 represented according to the invention. Such parts as those of the DEC air conditioning 100 to 1 are provided with reference numerals having a value increased by the value 100. For example, the sorption device 205 identical designed as the sorption 105 , In this respect, the above description of the elements of the 1 also the in 3 shown corresponding elements.

At the DEC air conditioning 200 according to the embodiment of the invention is in the supply air path 201 between the heat recovery unit 206 and the supply humidifier 207 a supply air heat exchanger 211 arranged. The supply air heat exchanger 211 is with a magnetocaloric cooling device 212 connected, via which the supply air heat exchanger 211 a cooled cooling fluid for additional cooling of the heat recovery unit 206 exiting outside air is supplied. The supply air heat exchanger 211 is on a cold side of the magnetocaloric cooling device 212 Tailored, so that the supply air heat exchanger 211 with cooled cooling fluid from the magnetocaloric cooling device 212 is fed. That in the supply air heat exchanger 211 heated cooling fluid is returned to the magnetocaloric cooling device 212 directed. On a warm side of the magnetocaloric cooler 212 is the exhaust air heat exchanger 209 tethered. The exhaust air heat exchanger 209 cooling fluid is supplied, which in the magnetocaloric cooling device 212 was heated. This in the exhaust air heat exchanger 209 Cooled cooling fluid is sent to the magnetocaloric cooling device 212 returned. The magnetocaloric cooling device 212 , the supply air heat exchanger 211 and the exhaust air heat exchanger 209 together make up a magnetocaloric peak load chiller.

The magnetocaloric cooling device 212 is using electrical energy from a photovoltaic system 213 provided. The photovoltaic system is preferably in the immediate vicinity of the room to be air conditioned 202 arranged so that the room 202 and the photovoltaic system 213 are exposed to substantially the same solar radiation. This results in the advantage that with increased solar radiation, ie at increased risk of undesired heating of the room 202 , electrical energy for operation of the magnetocaloric cooling device 212 can be provided. At the DEC air conditioning 200 Thus, an automatic activation of the photovoltaic system takes place 213 , the magnetocaloric cooling unit 212 and the supply air heat exchanger 211 provided peak load refrigeration system. Even with strong solar radiation can thus provide sufficient air conditioning of the room 202 respectively. The about the photovoltaic system 213 generated electrical energy is completely for operation of the magnetocaloric cooling unit 212 used. There is no additional electrical energy to operate the magnetocaloric cooling unit 212 required. The peak load refrigeration system, in particular the magnetocaloric refrigeration unit 212 , therefore does not have to be connected to a public power grid. In this respect, a self-regulating, self-sufficient peak load refrigeration system is provided.

The 4 and 5 show an hx diagram of the DEC air conditioning system according to the invention 200 operational.

It can be seen that the outside air AU in the sorption device 205 ie the transition between the points 2 and 3 , dehumidified and heated. In the next step in the heat recovery unit 206 ie the transition between the points 3 and 4 , there is a cooling of the air in the supply air path. About the supply air heat exchanger 211 An additional cooling of the air takes place at the transition between the points 4 and 4 ' , Finally, the air in the supply humidifier 207 moistened and cooled, cf. the transition between the points 4 ' and 5 ' , By adjusting the cooling capacity of the cooling device 212 can be different in 5 points shown 4 ' ¹ , 4 ' ² , 4 ' ^x and thus also corresponding points 5 ' ¹ , 5 ' ² , 5 ' ^{x be} set.

The exhaust air AB of the room 202 is in the exhaust humidifier 208 moisturizes and cools, as is the transition between the points 6 and 7 can be seen. In the subsequent process step in the heat recovery unit 206 becomes the air of the exhaust air path 203 heated, cf. Transition between the points 7 and 8th , This is followed by further heating in the exhaust air heat exchanger 209 , see. Transition between the points 8th and 9 , Finally, the air of the exhaust air path 203 in the sorption device 205 moistened and cooled, cf. Step by step 9 to point 10 , and then discharged as exhaust air FO to the environment.

The DEC air conditioner described above 200 for air conditioning of a room has a Zuluftpfad 201 , via which from sucked outside air AU cooled supply air ZU for a room 202 is providable, and an exhaust path 203 on, over which exhaust AB of the room 202 as exhaust air FO is deliverable to the environment. The DEC air conditioning 200 includes a sorption device 205 , via which of the outside air AU in the supply air path 201 Moisture extractable and this moisture to the exhaust AB in the exhaust path 203 is deliverable. The DEC air conditioning 200 further comprises a heat recovery unit 206 over which of those in the sorption device 205 Dehumidified outside air AU in the supply air path 201 Heat can be withdrawn and this heat to the exhaust air AB in the exhaust path 203 is dispensable, and a Zuluftbefeuchter 207 over which the from the heat recovery unit 206 exiting outside air is moistened to cool the outside air by evaporation. In the supply air path 203 is between the heat recovery unit 206 and the supply humidifier 207 a supply air heat exchanger 211 arranged, wherein the supply air heat exchanger 211 with a cooling device 212 is connected, via which the supply air heat exchanger 211 a cooled cooling fluid for additional cooling of the heat recovery unit 206 exiting outside air is zuleitbar. In this respect, via the supply air heat exchanger 211 a peak load refrigeration system is provided, which can be activated if necessary in strong sunlight to cool the supply air to a lower temperature.

LIST OF REFERENCE NUMBERS

1

outside air

2

sucked outside air

3

dehumidified outside air

4, 4 '

Dehumidified and cooled outside air

5, 5 '

supply air

6

exhaust

7

moistened exhaust air

8th

humidified and heated exhaust air

9

humidified and additionally heated exhaust air

10

Exhaust air of the sorption device

11

Exhaust air

100, 200

DEC air conditioning

101, 201

Zuluftpfad

102, 202

room

103, 203

exhaust path

104, 204

Conveyor

105, 205

sorption

106, 206

heat recovery unit

107, 207

Zuluftbefeuchter

108, 208

exhaust air humidifier

109, 209

Exhaust air heat exchanger

110, 210

Conveyor

211

Supply air heat exchanger

212

cooler

213

photovoltaic system

FROM

exhaust

AU

outside air

FO

Exhaust air

TO

supply air

Claims (11)

DEC air conditioning ( 200 ) for the air conditioning of a room ( 202 ), with a supply air path ( 201 ), via which from sucked outside air (AU) cooled supply air (ZU) for the room ( 202 ) and an exhaust air path ( 203 ), over which exhaust air (AB) of the room ( 202 ) can be discharged to the environment as exhaust air (FO), with a sorption device ( 205 ), via which of the outside air in the supply air path ( 201 ) Moisture and this moisture to the exhaust air in the exhaust air path ( 203 ) is deliverable, with a heat recovery unit ( 206 ), of which in the sorption device ( 205 ) dehumidified outside air in the supply air path ( 201 ) Heat can be withdrawn and this heat to the exhaust air in the exhaust air path ( 203 ) is deliverable, with a Zuluftbefeuchter ( 207 ), from which the heat recovery unit ( 206 ) outside air is humidified to cool the outside air by evaporation, characterized in that in the supply air path ( 201 ) between the heat recovery unit ( 206 ) and the supply air humidifier ( 207 ) an incoming air heat exchanger ( 211 ), wherein the supply air heat exchanger ( 211 ) with a cooling device ( 212 ), via which the supply air heat exchanger ( 211 ) a cooled cooling fluid for additional cooling of the heat recovery unit ( 206 ) exiting outside air is zuleitbar. DEC air conditioning system according to claim 1, wherein the cooling device ( 212 ) is designed as a magnetocaloric cooling device. DEC air conditioner according to claim 1, wherein the cooling device ( 212 ) is designed as a heat pump. DEC air conditioning system according to any one of the preceding claims, wherein the DEC air conditioning system ( 200 ) a photovoltaic system ( 213 ), over which the cooling device ( 212 ) can be supplied with electrical energy.  DEC air conditioner according to one of the preceding claims, wherein the DEC air conditioning is formed without a device for activating and / or controlling the cooling device. DEC air conditioning system according to any one of the preceding claims, wherein the DEC air conditioning system ( 200 ) one in the exhaust air path ( 203 ) arranged exhaust heat exchanger ( 209 ) connected to the cooling device ( 212 ), via which the exhaust air heat exchanger ( 209 ) a heated cooling fluid for additional heating of the heat recovery unit ( 206 ) delivered already heated exhaust air is zuleitbar. DEC air conditioner according to claim 6, wherein the exhaust air heat exchanger ( 209 ) in the exhaust air path ( 203 ) between the heat recovery unit ( 206 ) and the sorption device ( 205 ) is arranged. DEC air conditioning system according to one of the preceding claims, wherein in the exhaust air path ( 203 ) an exhaust air humidifier ( 208 ) for humidifying the exhaust air (AB) of the room ( 202 ) is arranged. Method for air conditioning a room ( 202 ), whereby via a supply air path ( 201 ) from sucked outside air (AU) cooled supply air (ZU) for the room ( 202 ) and via an exhaust air path ( 203 ) Exhaust air (AB) of the room ( 202 ) is discharged as ambient air (FO) to the environment, with the following process steps: - removal of moisture from the outside air in the supply air path ( 201 ) and discharging this moisture to the exhaust air ( 203 ) in the exhaust air path, - removal of heat from the already dehumidified outside air in the supply air path ( 201 ) and discharging this heat to the exhaust air in the exhaust path ( 203 ) by means of a heat recovery unit ( 206 ), - cooling of the heat recovery unit ( 206 ) exiting outside air by means of a supply air heat exchanger ( 211 ), wherein the supply air heat exchanger ( 211 ) with a cooling device ( 212 ), via which the supply air heat exchanger ( 211 ) a cooled cooling fluid for additional cooling of the heat recovery unit ( 206 ) outside air is supplied, and - humidifying the cooled outside air in the supply air path ( 201 ) to cool the outside air by evaporation. A method according to claim 9, wherein the cooling by means of the supply air heat exchanger ( 211 ) takes place only when the room to be air-conditioned ( 202 ) is exposed to an increased thermal load, in particular increased solar radiation. Method according to one of claims 9 or 10, wherein the cooling device ( 212 ) via a photovoltaic system ( 213 ) electrical energy is provided.

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