DE102008004244B3 - Workplace arrangement, has open cooling system comprising cooler with heat exchanger and fans above or at height of desk tops for sucking room air and for discharge of cooling air to monitors and/or into room - Google Patents

Abstract

The arrangement (2) has monitors (23, 24) arranged above desk tops (5, 6), and a cooler with a heat exchanger (10) and fans (13, 14) arranged for a closed table cooling system at the bottom side and under electronic data processing (EDV)-devices (8) e.g. computer. An open cooling system is provided for removal of dissipated heat of the monitors. The open cooling system has another cooler with a heat exchanger (20) and fans (21) above or at height of the desk tops for sucking room air (22) and for discharge of cooling air (27) to the monitors and/or into a room (9).

Description

The The invention relates to a workstation arrangement according to the preamble of claim 1.

The Invention is particularly for Stock exchange jobs suitable, where a job or two jobs are almost contiguous and can also be arranged next to each other to create a sequence, for example, in a C-shaped or arcuate shape.

Out DE 10 2005 038 719 A1 is a cooling arrangement for a work table with two worktops and arranged between them pedestal with holders for monitors and with a heat exchanger in a cabinet below the countertops known. The heat exchanger is supplied with heated ambient air through openings in the base and exhaust air from the computers arranged in the cabinet. The cooling air from the heat exchanger is divided by a divider with two fans in two air streams, with an air flow is discharged through controllable nozzles in the environment and in the direction of monitors, while the second air flow is directed to the computer.

For workstation arrangements with high-performance servers or personal computers, in which 2500 W and more heat loss per Device be dissipated must, is the well-known cooling concept unsatisfactory.

Out EP 1 630 485 A2 is a workstation arrangement known, which is to be used in particular as a dealer's table. The dealer table has two table tops, which almost adjoin each other at the rear, as well as a dome-like structure in the rear area, which coincides in terms of height with the monitors of the two work stations and extends across the width of the table tops. Below the two tabletops, a receiving space for computer equipment, in particular computer, is formed. Between the computer equipment, which are assigned to each workstation and arranged in each case at the front, one or two heat exchangers and a fan are accommodated in a housing, which can also be slightly raised and arranged protruding into the dome-like structure. The receiving space is not airtight, but has, in particular on the front sides, supply air openings for the room air. The heat exchanger is supplied with the waste heat of the EDP devices acted upon exhaust air and the air intake via the supply air, and cooled in the heat exchanger air is divided into several air outlets in partial air streams and fed in part to the computer equipment of the work table and the dome-like structure blown into the room.

The cooling concept the well-known dealer's table allowed due to dependencies between the table cooling and the room cooling only relatively limited optimization, especially the table cooling. By the use of common fans both for the table cooling as also for them room cooling are differentiated flow velocities not or only in a limited Circumference adjustable. Another disadvantage is the arrangement of the heat exchanger fan unit in the middle of the recording room and behind the computer equipment, which the accessibility and an exchange, such as the fan, difficult. The order the heat exchanger to the dome-like structure is associated with a risk of leakage for the computer equipment.

At one off DE 201 08 669 U1 known workplace arrangement is a cooling chamber with an air-water heat exchanger and an upstream fan above and arranged between the table tops of two workstations. The heated exhaust air of the arranged under table EDP devices is sucked up into the heat exchanger and passes as cooling air through an upper slot-shaped air outlet assembly of the cooling chamber into the room and lateral slots of the cooling chamber to monitors the workstations and openings in the table tops back into the Under table and to the computer equipment to be cooled. An optimization of the cooling of computer equipment in the lower table is not possible with the known device. In addition, there is also an increased risk of leakage through the arrangement of the air-water heat exchanger above the computer equipment.

Out DE 20 2007 001 857 U1 Workplace arrangements are known with two back side by side workplaces and with adjacent workstations. In the back-adjacent workstations, the heat loss of computer equipment, which are arranged in a receiving space below table tops, using a vertical air duct and an air-fluid heat exchanger and fans discharged to the outside. The receiving space is formed almost airtight and has an exhaust air area, which is vertically aligned between the rear sides of the computer equipment and connected to an exhaust air region, from which the exhaust air passes by means of the fans in the heat exchanger. The cooled air in the heat exchanger is fed via a horizontal cooling air space, which is formed by an intermediate floor below the heat exchanger, and a vertical cooling air space directly to the individual computer equipment.

For side-by-side workstations, the closed table cooling system with a storage compartment for computer equipment has a lateral free space for an air-fluid heat exchanger and superposed fans on. The free space communicates with a vertically oriented cooling air space. Both the vertical and horizontal air flow efficient, direct cooling of arranged in the recording room computer equipment is achieved. Cooling of the monitors arranged above the table tops and / or cooling the room air is not provided.

Of the Invention is based on the object, a workplace arrangement to create, which with a relatively small design effort an efficient and adaptable to the respective requirements respectively Optimizable cooling of computer equipment in a base cabinet or in a recording room the jobs while ensuring efficient room and / or monitor cooling.

According to the invention Problem solved by the features of claim 1. Advantageous and advantageous embodiments are in the subclaims and included in the figure description.

One The basic idea of the invention is a completely closed cooling system for the in a lower table or in a receiving space of the work place arrangement recorded computer equipment and an open cooling system for cooling of monitors and the installation space of the workstation arrangement and the closed table cooling system from the open cooling system Completely to separate.

According to the invention the workplace arrangement with two opposite ones jobs assigned table tops and a receiving space for computer equipment back and below the tabletops as well as with a closed table cooling system, to the exhaustion the heat loss of Monitors and / or for room cooling as an open cooling system another refrigerator with a heat exchangers and fans above or about the level of Table tops on, so that the room air warmed by the monitors from the fans sucked in and the heat exchanger supplied and be cooled in it can. The derivative of the in the heat exchanger of open cooling system cooled cooling air takes place in the direction of monitors and / or to the users and / or in the room.

This is according to the invention entire cooling unit of the closed Table cooling system with the heat exchanger and the fans bottom side below the computer equipment or the recording room arranged.

To a preferred embodiment of the heat exchanger is formed continuously and extends almost over the workplace width or the width of the receiving space.

Each Workplace is at least one fan for suction of the exhaust air from the computer equipment and to feed to the heat exchanger assigned.

In Viewed top view, the heat exchanger is advantageous about centered and lying flat in a floor space, and the fans, which preferably designed as a redundant fan pair are, are arranged to the right and left of the heat exchanger.

For a preferred air-technical separation of the workplaces and the associated EDP devices are Separators in the area of the heat exchanger and arranged in the receiving space, which formed for example as partitions could be. These are vertically aligned and perpendicular to the front sides jobs arranged. Through the air separation elements and also by means of heat exchanger fins A mutual influencing of opposing air flows and backflows is added a fan failure prevented.

By the redundant design of the fan can the closed table cooling system even after a fan fails provide the required service. Another advantage is remote monitoring the fan With the help of a monitoring system, as a result of a fan failure can be recognized immediately.

Conveniently, are the fans arranged and installed so that they are at any time individually and especially during of ongoing operations from the front of the respective workplace her dismantled and rebuilt or replaced can.

The Arrangement of the heat exchanger and the fan for the closed table cooling system below the receiving space is particularly advantageous because the computer equipment, for example Server, unhindered from the front can be inserted and the operating page for the user freely accessible is. Another advantage is that in the double workstation according to the invention showing the servers either to the front of one of the two workstations can be arranged. In addition, the backs are the server for a wiring freely accessible. The cooling device can be advantageous by a simple conversion of the fan quickly adapted to the current configuration.

The receiving space for the EDP devices, in particular server, is almost completely closed and thus separated from the surrounding space on the air side. In the receiving space of the workplace arrangement can therefore with a correspondingly high Strö tion rate, effective dissipation of the lost heat takes place. High noise levels or drafts at workplaces are avoided. A further advantage is that a fire detection / suppression system can be installed in the receiving space, which is independent of the installation space of the workplace arrangement and significantly increases the availability and security of the entire system.

Conveniently, are the heat exchanger and the fans of the closed table cooling system taken in a bottom space below the receiving space for the computer equipment. This bottom-sided space can be covered by cover plates, which are horizontal above of the continuous heat exchanger be arranged to be formed. The cover plates, which are both sides a separating element are arranged, have air inlet openings, especially above the fan pair, for feed the exhaust air from the receiving space in the bottom space and in on the heat exchanger. Opposite is at least one air outlet opening for feeding the in the heat exchanger cooled Air from the bottom space formed in the receiving space. In plan view can the fans, which the jobs are assigned to be arranged approximately diagonally.

It is advantageous as a heat exchanger for the closed Table Cooling System an air-fluid heat exchanger, in particular an air-water heat exchanger, which can be connected to the cold water network of the building, use. By the bottom-side arrangement of such a heat exchanger is the risk of damaging the Computer equipment almost impossible due to leakage. By the arrangement of a waterproof tub below the heat exchanger is ensured that even in the event of leakage, no water will get to the computer equipment can.

Basically, the closed table cooling system and a cooling device with a heat exchanger and fans and a horizontal and / or vertical air flow, for example according to DE 20 2006 015 995 U1 or DE 20 2007 011 857 U1 , exhibit.

It is an advantage that the cooling unit for the open cooling system the monitor and / or room cooling as a heat exchanger also an air-fluid heat exchanger and in particular may comprise an air-water heat exchanger. There is then the possibility the heat exchangers of the closed table cooling system and the open cooling system for the Monitors and the room in parallel or in series with the cold water pipe to join. When connected in series, it is expedient that the cold water first the Heat exchanger of the open cooling system for the Monitors and the room and then the heat exchanger of the closed Table cooling system supply.

Conveniently, is the heat exchanger for the monitor and / or room cooling relatively flat and formed between the monitors of the two workstations as well about about arranged the workplace width reaching. The fluidic downstream fan are below the heat exchanger arranged. A condensate tray below the heat exchanger also ensures that a leakage risk can be almost excluded.

For an efficient Monitor and or room cooling It is advantageous, the warm room air relatively high up in the room to suck in, preferably in the area of the hot air outlets of the monitors. The arrangement of at least one feed device is advantageous or a suction-side air guiding device, through which the heated ones Room air with the help of the fans the heat exchanger can be supplied in the range of table tops.

such feeding can be an air duct, which from the heat exchanger to above Monitors and preferably close to the ceiling of the installation room for the jobs enough. Such a duct can simultaneously for attachment of carriers for the Monitors be trained.

When suction-side feeder can also Air intake pipes are grown, which with upper openings almost directly at or above the Hot air outlets of the monitors can reach. Also the air intake pipes can as a carrying structure for the monitors are used.

Of the heat exchangers and the fans for the monitor and / or room cooling can be modular and in an upper space, which above the receiving space and formed between the table tops of the workstations is, be included. A cover of the upper space has air outlet openings which are arranged such that cooling air both in the direction of User and in the room as well as in the direction of the to be cooled Monitors can be blown out. Conveniently, the air outlet openings are adjustable in their cross-section and re the direction and, for example, formed like a nozzle.

In With respect to the feeder for the heated Room air, it is advantageous that the device at the same time guide of data and / or power cables can be used.

If above the monitors of both jobs a collecting hood is arranged, can, in particular with the help of a feeder, a vertical guidance of the heat exchanger to be supplied with the help of the fan room air can be achieved.

The Advantages of the workplace arrangement according to the invention exist in optimized cooling systems for the arranged in a sub-table or recording room computer equipment and also for the monitor or room cooling. By the complete Separation of the closed table cooling system from the cooling system for the Monitor and / or room cooling can be an optimization according to the different air conditioning Requirements are made and each of the two cooling systems independently optimally adjusted and operated.

For the cooling of the Computer equipment in the lower table or recording room is usually a Cooling air temperature of 22.5 ° +/- 2.5 ° C. The exhaust air temperature can be between about 30 ° and 45 ° C. Being on a relative narrow space a fairly high cooling capacity is required relatively high air flow rates and a tightly controlled leadership the cooling air flow will be realized. The associated relatively strong noise Can with both cooling systems through a complete Encapsulation to the outside almost complete insulated become. With that you can also relatively high demands on a very low noise emission Fulfills become. Furthermore becomes the workplace arrangement according to the invention the relatively high demands on availability and reliability the cooling the computer equipment just. Due to the redundant design of the fan with optional monitoring and by the simple replacement of the fans as well as the whole Cooling unit are high availability and reliability guaranteed.

For the cooling of the Monitors, in particular TFT screens, and surrounding the workstation arrangement Space requirements exist, which, for example, as a temperature that of the heat exchanger discharged cooling air about 18 ° C provide. Such a temperature usually ensures a adequate cooling and is not perceived as unpleasant by the users of the workstations. Also, relatively low flow rates for the To provide cooling air supply, so that the draft and noise emissions as possible are low. The temperature of the heated room air is about 26 ° C and differs significantly from the exhaust air temperatures in the Under-table or in the recording room for the computer equipment. The separated according to the invention cooling systems The workplace layout meets these requirements. moreover is also a compensation for any failure of a cooling system possible through the other system. The different requirements for the cooling capacity or to the cooling air streams and their Speeds can be relatively easy through an appropriate Design of the heat exchangers and the fan for the closed table cooling system or the open cooling system for the Monitor and / or room cooling be followed.

The Invention will be further explained below with reference to a drawing; in These show in a highly schematic representation

1 a vertical section through a workstation arrangement according to the invention;

2 a plan view of the bottom space with heat exchanger and redundant fan pairs;

3 a highly schematic representation of the monitor and / or room cooling with an air duct as a feeder for the heated air from the monitors room air;

4 a highly schematic representation of the monitor and / or room cooling with Luftansaugrohren as a feeder for the heated air from the monitors room air; and

5 a highly schematic representation of the monitor and / or monitor cooling with a collecting hood and an air duct as a feeder for the warmed by the monitors room air.

The workplace arrangement 2 of the 1 has two opposite jobs 3 . 4 and associated tabletops 5 . 6 on.

A recording room 7 for computer equipment 8th , for example, personal computer and server, is back under and between the tabletops 5 . 6 arranged and formed substantially airtight. The recording room 7 is in a sub-table or a table substructure 35 trained, and the tabletops 5 . 6 be on this table substructure 35 via support arms 36 held. Advantageous are the computer equipment 8th in a holder 37 taken and with this toward at least one table top, but preferably in the direction of both table tops 5 . 6 , extractable.

To dissipate the heat loss of computer equipment 8th in the recording room 7 is a cooling device below the receiving space 7 in a floor space 9 arranged, which has a heat exchanger 10 as well as fans 13 . 14 for a closed table cooling circuit (see also 2 ).

Above the tabletops 5 . 6 rejects the Ar beitsplatzanordnung 2 monitors 23 . 24 on which the jobs 3 . 4 are assigned and to monitor carriers 25 are attached. The monitor orders 25 be at the table construction 35 attached in a manner not described in detail.

For cooling the monitors 23 . 24 and / or the installation room 29 in which the workplace arrangement 2 is arranged, an open cooling system is provided which above or approximately equal to the table tops 5 . 6 in an upper room 33 a heat exchanger 20 and fans 21 having. The fans 21 are radial fans with a lateral cooling air outlet, which are those of the monitors 23 . 24 heated room air 22 suck in, the heat exchanger 20 feed and as cooling air 27 towards the monitors 23 . 24 and / or in the direction of the user or in the room 29 blow out.

1 conveys that the upper space 33 for the open cooling system with heat exchanger 20 and fans 21 for the open cooling system above the receiving space 7 , for the computer equipment 8th and is formed separately therefrom and a cover 34 with air outlet openings 39 for the cooling air 27 having the open cooling system. The air outlet openings 39 can be formed nozzle-shaped and directionally adjustable and adjustable in cross-section.

As a heat exchanger 20 the monitor and / or room cooling can also be used an air-water heat exchanger, which as the heat exchanger 10 of the closed table cooling system z. B. separately, in parallel or serially connected to the cold water network of the building (not shown). It is advantageous that the heat exchanger 10 . 20 can be adapted to the different cooling capacities with the same modular design and are therefore connected separately to the supply of cold water. It is also conceivable that the cold water first through the heat exchanger 20 for monitor and / or room cooling and then through the heat exchanger 10 of the closed table cooling system can be performed.

Both heat exchangers 10 . 20 are how out 1 shows approximately centered, with the heat exchanger 20 the open cooling system for the monitors 23 . 24 and the room 29 between the monitors 23 . 24 jobs 3 . 4 is located during the heat exchanger 10 below the computer equipment 8th in the floor space 9 is arranged. Below the heat exchanger 10 . 20 is in each case a waterproof tub or condensate tray 16 . 28 arranged.

2 shows in a plan view of the arrangement of almost the entire width B of the workplace arrangement 2 reaching heat exchanger 10 , 2 also shows that every job 3 . 4 at least one fan 13 . 14 for sucking in the exhaust air 12 (please refer 1 ) of the computer equipment 8th and for feeding to the heat exchanger 10 assigned. The fans 13 . 14 are designed as a redundant fan pair and in the plan view of 2 seen, arranged approximately diagonally.

For an air-technical separation of the workplaces 3 . 4 are separating elements 31 in the area of the heat exchanger 10 and the recording room 7 (not shown), which are vertically aligned and perpendicular to the front sides of the workstations 3 . 4 are arranged. Above the continuous heat exchanger 10 and on both sides of the separating element 31 each is a cover plate 11 arranged horizontally, which air inlets 18 , in particular above the fan pair 13 . 14 for supplying the exhaust air from the receiving space 7 and in the floor space 9 and in the heat exchanger 10 as well as approximately opposite at least one air outlet opening 19 for supplying the cold air 17 from the heat exchanger 10 and the floor space 9 in the recording room 7 has (see also 1 ).

The 3 to 5 show devices for an advantageous intake or supply of the monitors 23 . 24 heated room air 22 to the heat exchanger 20 of the open cooling system.

In 3 is as a feeder 40 an air shaft 41 arranged, which according to the heat exchanger 20 dimensioned and spread across the width of jobs 3 . 4 can extend. The air shaft 41 extends from the heat exchanger 20 and a filter 26 above the heat exchanger 20 at least up to the monitors 23 . 24 , preferably close to the ceiling of the installation room 29 for the workplace arrangement or almost to a collecting hood 45 , what a 5 is shown.

This collecting hood 45 extends horizontally across the monitors 23 . 24 jobs 3 . 4 and is provided with bent longitudinal edges, so that the output of the monitors hot air 22 caught and in a vertical air flow 30 down in the direction of the heat exchanger 20 with the help of the fan 21 is sucked. In this way, efficient monitor and / or room cooling is achieved.

4 shows as air supply 40 bilaterally arranged air intake pipes 42 whose upper openings 43 almost over the air outlet openings of the monitors 23 . 24 are arranged.

Claims (19)

Workplace arrangement with one or two opposite workstations ( 3 . 4 ) and associated tabletops ( 5 . 6 ), a recording room ( 7 ) for computer equipment ( 8th ), which on the back and below the table tops ( 5 . 6 ) is arranged and almost airtight, with a cooling device, which is a heat exchanger ( 10 ) and fans ( 13 . 14 ) to dissipate the heat loss of the computer equipment ( 8th ) in a closed table cooling system with a horizontal and / or vertical air duct, and with monitors ( 23 . 24 ), which above the tabletops ( 5 . 6 ) are arranged, characterized in that the cooling unit with the heat exchanger ( 10 ) and the fans ( 13 . 14 ) for the closed table cooling system on the bottom side and below the EDP devices ( 8th ) and that to dissipate the heat loss of the monitors ( 23 . 24 ) and / or room cooling an open cooling system is provided, which above or about the height of the table tops ( 5 . 6 ) another cooling unit with a heat exchanger ( 20 ) and fans ( 21 ) for the suction of the monitors ( 23 . 24 ) heated room air ( 22 ) and supply to the heat exchanger ( 20 ) of the further cooling device and for the discharge of the cooling air ( 27 ) to the monitors ( 23 . 24 ) and / or in the room ( 9 ) having. Arrangement according to claim 1, characterized in that the bottom side arranged heat exchanger ( 10 ) for the closed table cooling system continuously almost across the width of the receiving space ( 7 ) of jobs ( 3 . 4 ) and every job ( 3 . 4 ) at least one fan ( 13 . 14 ) for sucking in the exhaust air ( 12 ) from the computer equipment ( 8th ) and supply to the heat exchanger ( 10 ) assigned. Arrangement according to claim 1 or 2, characterized in that the heat exchanger ( 10 ) of the closed table cooling system is arranged approximately centrally and lying flat and the fans ( 13 . 14 ) designed as a redundant fan pair and each one of the workstations ( 3 . 4 ) assigned. Arrangement according to one of the preceding claims, characterized in that for an air-technical separation of the workstations ( 3 . 4 ) Separating elements ( 31 ) in the region of the heat exchanger ( 10 ) and the recording room ( 7 ) which are vertically aligned and perpendicular to the front sides of the workstations ( 3 . 4 ) are arranged. Arrangement according to claim 4, characterized in that for the formation of a bottom-side space ( 9 ) for the heat exchanger ( 10 ) and the fans ( 13 . 14 ) above the continuous heat exchanger ( 10 ) and on both sides of the separating elements ( 31 ) each a cover plate ( 11 ) is arranged horizontally and that each cover plate ( 11 ) Air inlets ( 18 ), in particular above the fan pair ( 13 . 14 ), for supplying the exhaust air ( 12 ) from the recording room ( 7 ) in the bottom space ( 9 ) and in the heat exchanger ( 10 ) and approximately opposite at least one air outlet opening ( 19 ) for supplying the cold air ( 17 ) from the heat exchanger ( 10 ) and the floor space ( 9 ) in the reception room ( 7 ) having. Arrangement according to one of the preceding claims, characterized in that the fans ( 13 ) of the workplace ( 3 ) approximately diagonally to the fans ( 14 ) of the workplace ( 4 ) are arranged and in particular during operation can be removed or replaced. Arrangement according to one of the preceding claims, characterized in that as a through-going heat exchanger ( 10 ) For the closed table cooling system, an air-fluid heat exchanger, in particular an air-water heat exchanger, which is connected to the cooling water network of the building, is used. Arrangement according to one of the preceding claims, characterized in that the cooling device for the monitor and / or room cooling as a heat exchanger ( 20 ) an air-fluid heat exchanger, in particular an air-water heat exchanger according to the heat exchanger ( 10 ) of the closed table cooling system, and that the cooling fluid the two heat exchangers ( 10 . 20 ) can be fed in parallel or in series. Arrangement according to one of the preceding claims, characterized in that the heat exchanger ( 20 ) of the refrigerator for monitor and / or room cooling relatively flat and between the monitors ( 23 . 24 ) of the two workstations ( 3 . 4 ) and is arranged as a maximum over the workplace width reaching and that the downstream fan ( 21 ) below the heat exchanger ( 20 ) and a watertight tub ( 28 ) are arranged. Arrangement according to one of the preceding claims, characterized in that the heat exchanger ( 20 ) and fans ( 21 ) for monitor and / or room cooling in an upper room ( 33 ), which above the receiving space ( 7 ) and between the tabletops ( 5 . 6 ) is formed, and that a cover ( 34 ) of the upper room ( 33 ) with in particular adjustable air outlet openings ( 39 ) for supplying cooling air ( 27 ) from the heat exchanger ( 20 ) to the monitors ( 23 . 24 ) and / or users of jobs ( 3 . 4 ) and / or in the room ( 29 ) is provided. Arrangement according to one of the preceding claims, characterized in that the heat exchanger ( 20 ) of the monitor and / or room cooling is modular. Arrangement according to one of the preceding claims, characterized in that as a fan ( 13 . 14 . 21 ) of the closed table cooling system and the monitor and / or room cooling diagonal fans are used. Arrangement according to one of the preceding claims, characterized in that above the heat exchanger ( 20 ) for the monitor and / or room cooling at least one feeder ( 40 ), through which the monitors ( 23 . 24 ) heated room air ( 22 ) with the help of the fans ( 21 ) the heat exchanger ( 20 ) can be fed. Arrangement according to claim 13, characterized in that as feeder ( 40 ) an air shaft ( 41 ), which of the heat exchanger ( 20 ) to beyond the monitors ( 23 . 24 ), preferably close to the ceiling of the installation room ( 29 ) for the jobs ( 3 . 4 ), enough. Arrangement according to claim 14, characterized in that the air shaft ( 41 ) for mounting monitor carriers ( 25 ) is trained. Arrangement according to claim 13, characterized in that as feeder ( 40 ) Air intake pipes ( 42 ) which are arranged with upper openings ( 43 ) almost directly to or via the monitors ( 23 . 24 ) pass. Arrangement according to claim 16, characterized in that the air intake pipes ( 42 ) as support structure for the monitors ( 23 . 24 ) are formed. Arrangement according to one of claims 13 to 17, characterized in that the feed device ( 40 ) is simultaneously used to guide data and / or power cables. Arrangement according to one of the preceding claims, characterized in that above the monitors ( 23 . 24 ) a collecting hood ( 45 ) for the monitors ( 23 . 24 ) heated, rising warm air ( 22 ) and that the hot air ( 22 ) in a vertical air flow ( 30 ) down, in particular in a feeder ( 40 ), with the help of the fans ( 21 ) the heat exchanger ( 20 ) is supplied.