WO2008143503A1

WO2008143503A1 - Data center

Info

Publication number: WO2008143503A1
Application number: PCT/NL2008/050295
Authority: WO
Inventors: Robbert Mees Lodder; Marcel Van Dijk
Original assignee: Kyotocooling International B.V.
Priority date: 2007-05-18
Filing date: 2008-05-19
Publication date: 2008-11-27
Also published as: NL1033871C2

Abstract

Data center comprising at least one space (101) with ICT and/or telecom equipment (102) to be air humidity- and temperature-conditioned, characterized in that the data center comprises cooling cells (100), while, depending on required cooling capacity of the space to be conditioned, a part of the number of these cooling cells.is furnished with at least one air-to-air heat exchanger (108), a cooling cell being provided with a supply opening (118) for supplying air to be cooled from the space (101) to be conditioned, a discharge opening (119) for discharging cooled air to the space to be conditioned, an outside air supply opening (110) and an outside air discharge opening (119).

Description

Title: Data center

The invention relates to an apparatus and method for cooling a space in a data center using recirculation air, which space is air humidity- and temperature-conditioned and in which ICT and/or telecom equipment is arranged. Data centers are generally known and usually comprise at least one space in which ICT and/or telecom equipment is arranged, such as computer, server or network equipment. For a proper operation of the equipment, an optimum and stable temperature and air humidity in the space are important. A good operating temperature for the equipment is between about 2O⁰C and about 25°C and a proper air humidity is between about 45% and about 5δ%. In view of the heat production of the ICT and/or telecom equipment, it is desirable to cool the space in order to keep the space at a stable temperature and air humidity. A data center is usually in operation 24 hours a day, seven days a week, and so the ICT and/or telecom equipment should be cooled practically continuously.

To cool the space, it is usually provided with a raised floor under which a cold air stream is blown. Via apertures in the floor, the air stream is blown into the space. At the top of the space, the heated air stream is extracted and, after cooling, the cooled air stream is again blown under the raised floor. Thus, the air stream is recirculated in the space.

The air stream is cooled by means of a cooling unit, usually a compression cooling unit in which a refrigerant, is compressed. The heated air stream gives off its heat to the refrigerant or to a cooling liquid functioning as intermediate medium. Usually, water is utilized as intermediate medium to carry the released heat out of the space.

The ICT and/or telecom equipment is usually placed in a system cabinet. Known system cabinets can be cooled in a vertical manner or in a horizontal manner. With cooling in a vertical manner, cold air flow is blown into the system cabinet at the bottom thereof and then, by fans, transported upwards, along the way cooling the equipment. A disadvantage is that the cold air stream heats up gradually, so that the air stream in the upper region of the system cabinet is warmer than the air stream in the lower region of the system cabinet. Due to this gradual heat-up of the air stream in the system cabinet for cooling the equipment, only a limited amount of equipment can be placed in the system cabinet, so that not the whole system cabinet can be utilized.

With cooling in a horizontal manner, the cooled air stream is passed horizontally through the equipment arranged in the system cabinet, by means of fans of the ICT and/or telecom equipment. The heated air stream leaves the system cabinet at the back. A disadvantage is that the heated air stream of one system cabinet can mix with the cooled air stream of another system cabinet. Another disadvantage of vertical cooling is that cooled air flow, without cooling any equipment, can mix with heated air.

Cooling through recirculation air an air humidity- and temperature-conditioned space in a data center in which ICT and/or telecom equipment is arranged, is not done efficiently in the known manner. Usually, the air stream is cooled to a temperature that is considerably lower than the operating temperature. Furthermore, use iβ made of relatively complex cooling units, and cooling involves much loss. As a consequence, much energy is required and the electricity costs of a data center are high. Especially in the case of a large data center, the costs of energy consumption consequently account for a considerable part of the total operational costs of the data center. Since the refrigerant is typically a propellant, in case of leakage of the refrigerant from the cooling unit, propellant may end up in the atmosphere, causing an environmental impact. Moreover, as a consequence of the use of water to dissipate the released heat from the space, water conduits are present in the space. These might start to leak *-^? I M , ι_ _Lυυo / u -_> y ^ u and then constitute a danger to the ICT and/or telecom equipment arranged in the space.

The object of the invention is to provide an apparatus of the type mentioned in the opening paragraph hereof which, while maintaining the above-mentioned advantages, can obviate the above-mentioned disadvantages.

To that end, the invention provides an apparatus for cooling by means of recirculation air an air humidity- and temperature-conditioned space in a data center in which ICT and/or telecom equipment is arranged, characterized in that the apparatus comprises an air-to-air heat exchanger, wherein recirculation air heated by the equipment is supplied as a first air stream to the air-to-air heat exchanger, and wherein the first air stream is cooled using a separate second air stream.

By providing an air-to-air heat exchanger, no use needs to be made anymore of a complex cooling unit with refrigerant and any intermediate medium, so that cooling is done more efficiently. This can yield a considerable saving of energy and hence of costs. Also, the environmental impact is reduced, because less energy is needed.

Since no refrigerant is needed anymore, the environmental impact - resulting from leaking propellant — is also reduced.

Preferably, the first air stream cooled by the air-to-air heat exchanger is supplied to the equipment separately from the air stream heated by the equipment. This prevents the heated first air stream from mixing with the cooling air, so that the temperature of the air stream cooled by the air-to-air heat exchanger can be approximately equal to the desired operating temperature. This yields a further saving of energy and hence of costs.

In another advantageous embodiment, the second air stream is supplied from outside the conditioned space. This can for instance be air from another space in the data center, or outside air. By making use, for instance, of outside air, the recirculation air can be cooled in an advantageous manner.

In an advantageous embodiment, the air-to-air heat exchanger is designed as a heat wheel. An advantage of the heat wheel is the efficient manner of heat transfer from the first air stream to the second air stream. Moreover, hardly any moisture transport needs to take place between the first and the second air stream, so that the air humidity of the first air stream remains approximately equal. For the practically continuous cooling of the recirculation air in the space in the data center, a heat wheel can be utilized in a particularly efficient manner. Furthermore, the temperature of the cooled first air stream can be approximately equal to the operating temperature. In a region with a comparable climate to the Netherlands, and when using outside air flow as a second air stream, the heat wheel, at nonstop operation, can be used for nearly 80% of the time. Only for the residual 20% may the outside air stream be too warm and may limited additional cooling be needed which supplements the cooling using the heat wheel.

The invention further relates to a method for cooling by means of recirculation air an air humidity- and temperature-conditioned space in a data center in which ICT and/or telecom equipment is arranged, and to the use of an air-to-air heat exchanger, in particular a heat wheel, for cooling a recirculation air of an air humidity- and temperature-conditioned space of a data center in which ICT and/or telecom equipment is arranged. Further advantageous embodiments of the invention are represented in the subclaims. The invention will be elucidated with reference to an exemplary embodiment represented in a drawing. In the drawing:

Fig. 1 shows a schematic view of a space with equipment;

Fig. 2 shows a schematic view of an air-to-air heat exchanger.

It is noted that the figures are only schematic representations of a preferred embodiment of the invention that is described by way of non-limiting exemplary embodiment. In the figures, like or corresponding parts are designated with the same reference numerals.

In Fig. 1 a conditioned space 1 in a data center is shown. In the space 1, a stable temperature and air humidity prevail. Preferably, the air humidity is between 45% and 55%. In the space 1, ICT and/or telecom equipment 2 is arranged. The equipment 2 produces heat and is therefore cooled using an air stream that recirculates in the space 1. Preferably, the operating temperature of the equipment is between 20⁰C and 25°C. For the purpose of the air recirculation and the cooling, the space 1 is provided with a raised floor 3.

The equipment 2 comprises for instance computer, network or server equipment and is preferably arranged in a system cabinet 14. In this exemplary embodiment, system cabinets 14 are provided with a front 4 to which a cooled first air stream is supplied and a back 5 along which a heated first air stream is removed. The equipment 2 has a front 16 facing the front 4 of the system cabinet 14, and a back 17 facing the back 5 of the system cabinet 14.

To prevent heated air flow from mixing with the cooled first air stream, the system cabinets 14 have their fronts 4 facing each other, to thereby form a 'cold corridor' 6. In this exemplary embodiment, the cold corridor 6 is closed off with sidewalls and a ceiling 7, to thereby create a closed space within the space 1, and to separate the heated first air completely from the cooled first air stream. The heated first air is cooled by means of a cooling device 8, and the cooled first air stream is thereupon blown under the raised floor 3.

The recirculation of the first air stream in the space 1 proceeds as follows. A cooled first air stream 9 is blown under the raised floor 3. Adjacent the fronts 4 of the system cabinets 14, there are apertures in the floor through which the cooled first air stream 9 is blown. The cooled first air stream 9 is supplied to the fronts 4 of the system cabinets 14 and in them is drawn to the back 5 by the fans of the equipment 2 arranged in the system cabinets 14. On the way, the equipment 2 is cooled, as a result of which the cooled first air stream heats up, and the first air stream exits at the back 5 from the system cabinets 14 as a heated first air stream 10. Upon passing through the system cabinet 14, the cooled first air stream 9 will have heated up by some 6 to 12°C, on average, thereby rendered a heated first air stream 10. The heated first air stream 10 is outside the cold corridor 6 and cannot mix with the cooled first air stream 9 because of the ceiling 7. As a consequence, no losses occur and the cooled first air stream 9 can be presented to the equipment 2 at the operating temperature of the equipment 2, between 2O⁰C and 25⁰C. The cooled first air stream 9 exiting from an exit opening 19 of the cooling device 8 is thus supplied separately via a supply duct 15 to the front 16 of the equipment 2. The heated first air stream 10 is removed from the space 1 near the ceiling via a discharge duct, not shown, and is supplied to an inlet opening 18 of the cooling device. The first air stream thus recirculates in the space 1, while in this exemplary embodiment the cooled first air stream 9 is separated from the heated first air stream 10.

The cooling device 8 is designed as an air-to-air heat exchanger 8, to which the heated first air stream 10 is supplied. In the air-to-air heat exchanger 8, the heated first air stream 10 is cooled using a separate second air stream 12. Preferably, as shown in Fig. 1, the second air stream 12 is supplied from outside the space 1. In an advantageous embodiment, the second air stream 12 is outside air. In the air-to-air heat exchanger 8, the first air stream 10 and the second air stream 12 remain separate from each other, and therefore no mixing or substantially no mixing of first and second air stream takes place.

Fig. 2 shows a schematic view of an air-to-air heat exchanger 8. The air-to-air heat exchanger 8 is provided with a heat exchange body 13, for instance a metal plate with small apertures through which air can move. The plate can have any shape, but is preferably rectangular or circular. The heat exchange body 13 moves successively through the heated first air stream 10 and the cooler second air stream 12.

When the heat exchange body 13 moves through the heated first air stream 10, the heat exchange body 13 is heated up and the heated first air stream 10 cools down to a cooled first air stream. Next, the heated heat exchange body 13 moves through the cool incoming second air stream 12, as a result of which the second air stream 12 is heated up to a warm exiting second air stream and the heat exchange body 13 cools down. In an advantageous embodiment, the air-to-air heat exchanger 8 is designed as a heat wheel, as shown in Fig. 2. In a heat wheel, the heat exchange body 13 is designed as a circular thin metal wheel with small apertures through which air can move. An advantage of the heat wheel is that moisture transfer between the first and second air stream can be minimal, so that the air humidity of the first air stream 9, and hence the air humidity in the space 1, remains substantially unchanged. The construction of the heat wheel will not be discussed in more detail here, since it is well known to those skilled in the art. An example of the construction of a heat wheel is described in the publication 'Hoval Rotary Heat Exchanger for Heat Recovery in Ventilation Systems' HW 6OaEl 11/2002 as available on www .hoval.com of Hovalwerk AG, in particular on page 8 of the publication.

If the second air stream 12 is a stream of outside air, it can for instance be used up to an inlet temperature of 18°C for complete cooling of the heated first air stream to 22°C. Since the equipment in the space in the data center needs to be cooled substantially continuously, and since the outside air temperature including nights in countries of a climate type like the Netherlands is lower than 18⁰C for an average 80% of the time, the heat wheel can be deployed for cooling the data center for as much as 80% of the time without additional cooling. For the residual 20% of the time, the 8 ru i / NL i

temperature of the outside air stream will often be such that additional cooling is needed. Additional cooling can be realized with any other type of cooling device. In an environmentally friendly manner, additional cooling can for instance be carried out by means of soil storage, whereby air is drawn from a cool underground buffer space.

Since a cooling device 8 for cooling the first air stream in a conditioned space 1 in a data center is needed virtually continuously - 24 hours a day, seven days a week - the use of an air-to-air heat exchanger, and in particular of a heat wheel, is extremely efficient, as no refrigerant and cooling liquid are used. Thus, a considerable saving on energy consumption and hence on electricity costs can be achieved. Also, there is less environmental impact owing to the absence of an environmentally unsound refrigerant and owing to the lower energy consumption.

As long as a cooling demand is substantially unchanged — for instance in that the same amount of equipment 2 in the space remains active — and the temperature of the second air stream 12 is practically unchanged, a flow rate of the first air stream 9 and the second air stream 12 will likewise remain substantially unchanged, since the cooling demand depends on the amount of heat being produced by the equipment 2. Upon a change of the cooling demand, for instance in that more or less equipment 2 in the space 1 is active, the flow rate of the first air stream 9, 10 can be changed. If the temperature of the incoming second air stream 12 changes, for instance due to the surroundings becoming hotter or colder, also the flow rate of the second air stream 12 can be adjusted. As the flow rate of the second air stream 12 can be adjusted, it can be ensured that the temperature of the cooled first air stream 9 remains substantially unchanged. So, the flow rate of the second air stream 12 depends on the difference in temperature between the second air stream 12 and the first air stream 10. The flow rate can then be controlled depending on the desired temperature of the cooled first air stream, for instance 22°C. It will be clear that the invention is not limited to the exemplary embodiments represented here. For instance, the cooling device may be disposed inside the space or outside it, or - as shown in Fig. 1 — partly inside the space and partly outside. Also, the cooling device may be disposed outside the data center. If the cooling device is disposed outside the space, the heated first air stream will for instance be carried to the air-to-air heat exchanger via a ceiling of the space. The additional cooling can be done in various ways, for instance by adiabatic cooling or by means of a conventional liquid cooling. Such variants will be clear to those skilled in the art and are understood to be within the scope of the invention as set forth in the appended claims.

The invention also relates to a data center comprising at least one space for ICT and/or telecom equipment to be air humidity- and temperature-conditioned. When such data centers are newly built, about 70% of the total investment is intended for the realization of the electrical and mechanical installations. This investment is usually made at the start before or during the construction of the data center.

A disadvantage is that the investments for the infrastructure for electrical and mechanical installations, among which, for instance, a cooling installation, are made at once. Directly upon completion, however, the data center is usually not utilized up to its maximum capacity yet, so that a part of the infrastructure, while installed, is not in operation yet.

To this end, the invention provides a data center comprising at least one space with ICT and/or telecom equipment to be air humidity- and temperature-conditioned, wherein the data center comprises a number of cooling cells, and wherein only a part of the number of cooling cells present is furnished with at least one air-to-air heat exchanger and wherein the furnished cooling cell is provided with a supply opening for supplying air to be cooled from the space to be conditioned to the air-to-air heat exchanger, a discharge opening for discharging cooled air from the air-to-air heat exchanger to the space to be conditioned, an outside air supply opening for supplying cold outside air to the air-to-air heat exchanger, and an outside air discharge opening for discharging heated outside air from the air-to-air heat exchanger.

By furnishing only a part of the cooling cells of a data center that are present with an air-to-air heat exchanger to yield operational cooling cells, it is possible in a simple manner to furnish additional cooling capacity in a data center already built and put into use. Consequently, during construction, not all investments for the cooling installations need to be made yet, and investment in the cooling installations can be spread over the service life of the data center.

Depending on the required capacity of the space to be conditioned in the data center, cooling cells can be furnished with an air-to-air heat exchanger. Consequently, in the initial phase of the data center, when there is still little ICT- and/or telecom equipment in the data center space to be conditioned and the required cooling capacity is low, it is possible to furnish only a limited number of cooling cells with an air-to-air heat exchanger, the number of furnished cooling cells then being smaller than the number of cooling cells present. When subsequently more ICT- and/or telecom equipment is set up in the data center space to be conditioned, the required cooling capacity increases and more cooling cells can be furnished with an air-to-air heat exchanger to provide the required cooling.

It is advantageous to cool the space to be conditioned using recirculation air, whereby recirculation air heated by the equipment is supplied as a first air stream to the air-to-air heat exchanger wherein the first air stream is cooled using a separate second air stream. The second air stream is preferably outside air. To separate the first and the second air stream from each other, the cooling cell may be divided into subspaces by means of a partition. By virtue of the partition, no exchange between the first air stream and the outside air is possible. Partly by the use of recirculation air, a lower cooling capacity can suffice to meet the cooling demand of the space to be conditioned.

In an advantageous embodiment, the air-to-air heat exchanger comprises a heat wheel, as described above for instance on p. 4, lines 3 — 16. By making use of a heat wheel, it is possible in a simple manner to furnish cooling cells after the data center has been put into use. No cooling water is required for use of a heat wheel, so that no piping system needs to be installed in the data center space to be conditioned. Consequently, investment can be reduced.

Preferably, the heat wheel is arranged horizontally in the cooling cell. A horizontal arrangement of the heat wheel allows the height of the cooling cell to be limited, so that no unduly high spaces are needed in the data center. This saves space and money. Advantageously, the cooling cells are disposed alongside the space to be conditioned. As a consequence, the supply and discharge ducts from the space to be conditioned to the cooling cell can be short.

In a simple manner, the cooling cells are placed such that one side borders on the space to be conditioned and another side borders on the outside air. In such an arrangement, no long ducts are needed for supplying and discharging the air to be cooled from the space to be conditioned and the outside air. Possibly, such ducts can even be omitted.

In an advantageous embodiment, the cooling cell is further provided with an auxiliary cooling device. This auxiliary cooling device can take over the cooling of air to be cooled when the outside air temperature is too high and the air-to-air heat exchanger cannot cool sufficiently.

Preferably, the auxiliary cooling device is substantially supplied by an emergency power generating set. More preferably, the auxiliary cooling device is supplied solely by the emergency power generating set. The auxiliary cooling device then does not require installation of additional mains supply lines to the cooling cell, which yields a saving of cost.

Preferably, in the space to be conditioned, the air stream cooled by the air-to-air heat exchanger is separated from the air stream heated by the ICT- and/or telecom equipment. Since the cooled air stream and the heated air stream are separated, they no longer mix with each other and hence a lower cooling capacity can suffice.

It is particularly advantageous when in the cooling cell an air return device is provided, allowing air to be guided past the air-to-air heat exchanger. When the outside air temperature is too low, the air to be cooled from the space to be conditioned is cooled too much. In that case, it is advantageous for a part of the air-to-be-cooled to be guided not via the air- to-air heat exchanger, but via an air return device to mix with cooled air to thereby prevent the temperature of the cooled air becoming too low. Also, outside air already warmed up can be guided back via an air return device to the outside air still to be warmed. In this way, at a low outside air temperature, the temperature of the outside air to which the air-to-air heat exchanger gives off its heat is raised, to thereby prevent unduly strong cooling of the cooled air for the space to be conditioned. The invention also relates to a method for adapting cooling capacity of a space to be conditioned for ICT and telecom equipment in a data center, comprising furnishing the data center with cells, realizing a number of the cells as cooling cells by providing them with a supply opening for supplying air to be cooled from the space to be conditioned, a discharge opening for discharging cooled air to the space to be conditioned, an outside air supply opening, and an outside air discharge opening, furnishing a number of the cooling cells with an air-to-air heat exchanger, the number of furnished cooling cells being smaller than the number of cells present. By modularly building up the data center and furnishing it with cells for cooling, during construction not all infrastructure for the cooling installations needs to be installed directly, so that this investment does not need to be made at once but can be spread. This renders constructing a data center cheaper.

It is advantageous to enlarge the number of furnished cooling cells depending on the required cooling capacity of the space to be conditioned. As a result, the cooling capacity present can be adapted to the required cooling capacity, preferably this is done in steps. In this way, investments can be deferred.

The invention will be elucidated with reference to an exemplary embodiment represented in a drawing. In the drawing: Fig. 10 shows a schematic side elevation of a cooling cell;

Fig. 11 shows a schematic top plan view of cooling cells;

Fig. 12 show a schematic top plan view of a space with ICT and/or telecom equipment with cooling cells;

Fig. 13 shows a schematic side elevation of a data center according to the invention.

It is noted that the figures are only schematic representations of a preferred embodiment of the invention which is described by way of non- limiting exemplary embodiment. In the figures, equal or corresponding parts are indicated with the same numerals or numerals differing by 100. Fig. 10 shows a schematic side elevation of a cooling cell 100, which borders on the space 101 to be conditioned. In the space 101 to be conditioned, ICT and/or telecom equipment 102 is arranged. This equipment 102 produces heat and should therefore be cooled. Cooling of the space 101 to be conditioned is done by means of recirculation air, with recirculation air heated by the equipment 102 being supplied as a first air stream to the air- to-air heat exchanger 108. The first air stream is cooled using a separate second air stream, for instance outside air.

In the cooling cell 100 an air-to-air heat exchanger 108 is set up. In this exemplary embodiment, the air-to-air heat exchanger 108 is designed as a heat wheel. The heat wheel 108 is disposed horizontally and rotates about an upstanding axis. A description of a heat wheel has been given hereinabove, for instance on p. 7, lines 11-21.

The cooling cell 100 on a side 105 borders on the space 101 to be conditioned and on another side 106 borders on the outside air 107. The cooling cell 100 has a supply opening 118 for supplying air to be cooled from the space 101 to be conditioned, and a discharge opening 119 for discharging cooled air to the space 101 to be conditioned. Also, the cooling cell 100 comprises an outside air supply opening 110 and an outside air discharge opening 111. The cooling cell 100 is thus provided with a supply opening 118 for supplying air to be cooled from the space 101 to be conditioned to the air- to-air heat exchanger 108, a discharge opening 119 for discharging cooled air from the air-to-air heat exchanger 108 to the space 101 to be conditioned, an outside air supply opening 110 for supplying cold outside air to the air-to- air heat exchanger 108, and an outside air discharge opening 111 for discharging heated outside air from the air-to-air heat exchanger 108.

As the cooling cell 100 borders on the space 101 to be conditioned and on the outside air 107, no supply and discharge ducts are needed, and the air can be supplied and discharged via the openings 118, 119, 110 and 111. The air to be cooled enters the cooling cell 100 via the opening 118 and is then guided via the heat wheel 108. Via the heat wheel 108, the air to be cooled is cooled. The cooled air exits the cooling cell 100 via the opening 119 to the space 101 to be conditioned.

The cooling cell 100 is divided into two subspaces 116 and 117 by means of a partition 114. In subspace 116 is air from space 101 to be conditioned. In subspace 117 is outside air. Via heat wheel 108, the air to be cooled of the first air stream gives off its heat to the outside air in the space 117.

In an advantageous embodiment, the cooling cell 100 is provided with an air return device - not shown - along which air to be cooled can be guided to mix with air already cooled. This air return device would then be situated in the subspace 116 and enables a diversion for a part of the air to be cooled. This diverted air then does not pass along the heat wheel 108 but, via the air return device, is mixed directly with the cooled air. This can be used if the cooled air were to get too cold. By mixing it with heated air, the temperature of the air passing to the space to be conditioned can be kept acceptable for the equipment 102. Likewise, or alternatively, in the space 117 an air return device may be arranged along which outside air already heated can be guided to mix with outside air still to be heated, for instance if the outside air is very cold. In this way, an unduly strong cooling of the air from the space 101 to be conditioned can be prevented.

For a description of the cooling of the space to be conditioned using recirculation air and cooled air which is separated from heated air, reference is made to relevant passages hereinabove (for instance p. 5, line 206 to p. 6, line 18).

In Fig. 10 it can also be seen that the cooling cell 100 is equipped with an auxiliary cooling device 115. This can for instance be a cooling battery with a condenser in a compression cooling machine having about the same or a larger capacity than the capacity of the heat wheel 108. Should the heat wheel 108 fail or otherwise cool insufficiently, the auxiliary cooling device 115 can take over cooling. For a cooling cell 100 with a heat wheel 108 and an auxiliary cooling device 115, hence only cooling ducts for the auxiliary cooling device 115 in the cooling cell proper are needed. No cooling ducts in the space 101 to be conditioned are needed. The cooling cell 100 may also be equipped with an emergency power provision. In that case, no emergency power lines to the cooling cell 100 need to be installed. Preferably, the emergency power provision is an emergency power generating set. Only the air-to-air heat exchanger 108, fans and a control device in the cooling cell 100 are connected to mains supply. If the mains supply fails, a cooling cell 100 has its own emergency power provision to continue cooling, possibly with a short interruption required for starting up the emergency power provision. Also, such a short interruption may be compensated by emergency power generating sets. In this way, when building the data center, fewer provisions for ducts need to be made, which renders construction cheaper.

The auxiliary cooling device 115 present in the cooling cell 100 is preferably connected not to the mains supply but solely to the emergency power provision. For this, then, no additional mains supply line in and to the cooling cell 100 is needed. If the auxiliary cooling device 115 is switched on, it takes power from the emergency power provision. In this way, there are hardly any peaks anymore in the demand for mains power, since the additional power that is demanded by auxiliary cooling device 115 is supplied by the emergency power generating set. This results in a more constant loading of the electricity grid connection. Preferably, also the condenser — not shown — as part of an auxiliary cooling device 115 for heat delivery to the outside air is placed near the cooling cell, for instance at the outside air discharge opening 111. The fans already present in the cooling cell 100 for drawing in the outside air stream and the first air stream from the space 101 to be conditioned can advantageously be used in addition to draw in air for the condenser. In that case, the condenser itself does not need to be provided with fans and hence it does not need to be provided with power either, so that power lines to the condenser can be omitted.

When the cooling cell 100 has its own emergency power provision, no redundant cabling for mains power to the cooling cell 100 is needed anymore, either. This renders construction of such a data center cheaper.

The cooling cell 100 can be advantageously rendered more reliable by making temperature sensors of redundant design. For instance by providing the heat wheel with three temperature sensors instead of the usual single sensor, a sensor can fail without reducing the reliability of the temperature measurement. The third temperature sensor can meanwhile be remedied without requiring the heat wheel to be taken out of operation. By making use of recirculation air and separate cooled air from heated air in the space 101 to be conditioned, less cooling capacity is needed. Moreover, the use of a heat wheel 108 is particularly efficient. This results in a reduction of the required power consumption for cooling of the space to be conditioned by about 20% to 30% of the installed output of ICT and/or telecom equipment 102. Also, the power consumption is virtually stable — hardly any peak loading - and is little dependent on, for instance, the outside air temperature.

Fig. 11 shows a top plan view of a cooling cell 100 in which the horizontally disposed heat wheel 108 can be seen. Also to be seen is the partition 114 which separates the outside air stream from the first air stream and divides the cooling cell 100 into two subspaces 116 and 117. Fig. 12 shows a top plan view of a space 101 to be conditioned with

ICT and/or telecom equipment 102, alongside which cooling cells 100 are set up. As can be seen in Fig. 12, not all cooling cells 100 are provided with a heat wheel 108. Only a lesser number than the total number of cooling cells present have been furnished with at least one air-to-air heat exchanger as an operational cooling cell 100. By furnishing only a part of the data center cooling cells present with an air-to-air heat exchanger to yield operational cooling cells 100 it is possible in a relatively simple manner to furnish additional cooling capacity in a data center already built and put into use. As a result, during construction, not all investments for the cooling installations need to be made yet, and investment in the cooling installations can be spread over the service life of the data center. By making use of a cell structure with cooling cells 100 which are provided or not provided with an air-to-air heat exchanger 108, the cooling capacity present can stay in line with the required cooling capacity. The equipment 102 set up in the space 101 to be conditioned needs a particular amount of rU I / IML 18

cooling. To be able to meet this required cooling capacity, a number of cooling cells 100 can be furnished with air-to-air heat exchangers 108 and with a supply opening 118 for supplying air to be cooled from the space to be conditioned, a discharge opening 119 for discharging cooled air to the space to be conditioned, an outside air supply opening 110, and an outside air discharge opening 111. When subsequently more equipment 102 is set up in the space 101 to be conditioned, the required cooling capacity increases. The cooling capacity present can then be adapted stepwise by furnishing one or more additional cooling cells 100 with an air-to-air heat exchanger 108 and with a supply opening 118 for supplying air to be cooled from the space to be conditioned, a discharge opening 119 for discharging cooled air to the space to be conditioned, an outside air supply opening 110 and an outside air discharge opening 111.

When a cooling cell 100 is further provided with an emergency power provision of its own, the emergency power provision likewise becomes dependent on the amount of ICT and/or telecom equipment 102 that is set up in the space 101 to be conditioned and it can be adjusted in steps too.

Fig. 13 shows a schematic side elevation of a data center 120 having therein a number of spaces 101 to be conditioned and a number of cooling cells 100. As the heat wheel in the cooling cell 100 is arranged horizontally, the height of the cooling cell 100 and hence of the building layer in the data center 120 can remain limited. In this exemplary embodiment, it can be seen that per building layer cooling cells 100 are present which are furnished or not furnished with an air-to-air heat exchanger 108.

Possibly, a number of spaces 101 to be conditioned and situated above each other may be connected with a cooling cell 100. This may for instance be the case in the initial phase of the data center 120, when not the complete spaces 101 have been utilized yet for the placement of ICT and/or telecom equipment 102. Later, upon expansion of the ICT and/or telecom equipment 102, the cooling capacity can be simply adapted by furnishing one or more additional cooling cells with an air-to-air heat exchanger 108 and with a supply opening 118 for supplying air to be cooled from the space to be conditioned, a discharge opening 119 for discharging cooled air to the space 101 to be conditioned, an outside air supply opening 110 and an outside air discharge opening 111.

Many variants are possible and will be clear to those skilled in the art. Such variants are understood to fall within the scope of the invention as set forth in the following claims.

Claims

1. A data center, comprising at least one space with ICT and/or telecom equipment to be air humidity- and temperature-conditioned, wherein the data center comprises a number of cooling cells, and wherein only a part of the number of cooling cells present is furnished with at least one air-to-air heat exchanger, and wherein the furnished cooling cell is provided with a supply opening for supplying air to be cooled from the space to be conditioned to the air-to-air heat exchanger, a discharge opening for discharging cooled air from the air-to-air heat exchanger to the space to be conditioned, an outside air supply opening for supplying cold outside air to the air-to-air heat exchanger, and an outside air discharge opening for discharging heated outside air from the air-to-air heat exchanger.

2. A data center according to claim 1, wherein the space to be conditioned is cooled using recirculation air, wherein the data center comprises an air-to-air heat exchanger wherein recirculation air heated by the equipment is supplied as a first air stream to the air-to-air heat exchanger, and wherein the first air stream is cooled using a separate second air stream.

3. A data center according to claim 1 or claim 2, wherein an air-to-air heat exchanger comprises a heat wheel.

4. A data center according to claim 3, wherein the heat wheel is arranged horizontally.

5. A data center according to any one of the preceding claims, wherein the cooling cells are arranged alongside the space to be conditioned.

6. A data center according to any one of the preceding claims, wherein the cooling cells on one side border on the space to be conditioned and on another side border on the outside air. 2i Pυ ι/ r

7. A data center according to any one of the preceding claims, wherein the cooling cell is further provided with an auxiliary cooling device.

8. A data center according to claim 7, wherein the auxiliary cooling device is substantially supplied by an emergency power generating set.

9. A data center according to any one of the preceding claims, wherein in the space to be conditioned air stream cooled by the air-to-air heat exchanger is separated from air stream heated by the ICT and/or telecom equipment.

10. A data center according to any one of the preceding claims, wherein in a cooling cell an air return device is provided by which air can be guided to bypass the air-to-air heat exchanger.

11. A data center according to any one of the preceding claims, wherein the space to be conditioned is cooled using recirculation air.

12. A method for adapting cooling capacity for a space to be conditioned for ICT and telecom equipment in a data center, comprising

- furnishing the data center with cells;

- realizing a number of the cells as cooling cells by providing them with a supply opening for supplying air to be cooled from the space to be conditioned, a discharge opening for discharging cooled air to the space to be conditioned, an outside air supply opening, and an outside air discharge opening;

- furnishing a number of the cooling cells with an air-to-air heat exchanger, the number of furnished cooling cells being smaller than the number of cells present.

13. A method according to claim 12, wherein the number of cooling cells furnished with an air-to-air heat exchanger is enlarged depending on required cooling capacity of the space to be conditioned .

14. A method according to claim 12 or 13, wherein the number of cooling cells furnished with an air-to-air heat exchanger is enlarged in steps.