DE102009058055B4 - System and method for cooling a computer system - Google Patents

Abstract

System (1) for cooling a computing system (2), comprising a refrigeration machine (3) with which a fluid can be cooled, which fluid can be supplied to the computing system (2), waste heat from the computing system (2) being deliverable to the refrigeration machine (3), in order to supply the chiller (3) with drive energy at least partially, characterized in that a heat pump (10) is provided between the computer system (2) and the chiller (3) to increase the flow temperature of the chiller (3), the return (5 ) of the computing system (2) is first led over the refrigeration part of the heat pump (10) and then over the refrigeration part of the refrigeration machine (3).

Description

Field of the invention

The invention relates to a system and method for cooling a computer system, in particular for cooling a server farm.

Background of the invention

Computer systems, in particular server farms comprising a large number of racks, generate large amounts of heat during operation. Thus, a server farm usually comes to a pure heating power of several kilowatts.

To dissipate these large amounts of heat, air conditioners are usually used, the operation of which is very energy-intensive.

Although approaches are known in practice, with which attempts are made to use the waste heat of a computer system for heating a building. In many cases, however, such an approach is not possible in the vicinity because of the lack of heatable building surfaces and also, depending on the climatic zone and the season, not suitable for ensuring adequate cooling of a computer system present in a building.

It is estimated that the energy needed for server farms will grow to 100 GWh or more over the next few years, with 40% of that energy being added to refrigeration alone.

Conventional computer systems are usually cooled by the air conditioning of the room, the individual computers via a fan heat to the ambient air.

However, there are also newer approaches in which the racks of a computer system are cooled by a liquid, wherein the cooling air of the racks emit their heat energy to a liquid to be cooled outside the rack via a rack integrated or adapted in the rack.

Another approach is to dissipate the heat energy directly from the processors via liquid cooling. Although this technique has the advantage that a large portion of the resulting heat can be dissipated on a small local volume, in practice it is at least not implemented on an industrial scale, possibly due to the fact that the technical difficulties associated with the liquid cooling of processors, such as Sufficient assurance of tightness, still not in any meaningful relationship to their use.

In the course of further increasing computing power in ever smaller space, it can be assumed that the cooling capacity and the associated energy consumption will rise as well.

The document US 2005/132 724 A1 shows a two-stage cooling. It should be achieved via an absorption chiller, a higher efficiency.

Object of the invention

The invention is based on the object to reduce the energy requirements of conventional cooling for computer systems.

It is not necessary to rely on location-based external sources.

Description of the invention

The object of the invention is already achieved by a system for cooling a computer system and by a method for cooling a computer system according to one of the independent claims.

Preferred embodiments and further developments of the invention are to be taken from the respective subclaims.

The invention relates to a system for cooling a computer system. A computing system is understood to mean an arrangement having a plurality of computers, in particular a data center or a server farm. As a rule, such a computing system has a modular structure in which racks are provided, in which the individual boards and / or assemblies are arranged, in particular inserted.

The system is intended in particular for cooling computer systems whose heat output is more than 5 kW, preferably more than 50 kW.

The system comprises a refrigeration machine, with which a fluid can be cooled, which can be supplied to the computer system. Preferably, air or a liquid, in particular water, is supplied for cooling the computer system. However, it is also conceivable to feed a coolant, which is used in the chiller, directly to the computer system.

Cooling with air generally takes place in that the room in which the individual computers are located, is itself cooled and / or the computers have their own internal air cooling, give off waste heat to the ambient air and thus the waste heat via the ambient air is kept within a predetermined target temperature range, is dissipated.

In systems with higher computing power is usually provided using air cooling air cooling for the individual racks, that is, the waste heat is not alone on the ambient air of the room, but it is carried out directly air or blown into the racks, so that a more localized heat dissipation is possible. With such rack cooling necessary flow temperatures of the cooling air vary depending on the performance and technical design of the computer, for example, the flow temperature of the cooling air in the range 20 ° C to 25 ° C are.

Another embodiment is the liquid cooling of racks. The liquid cooling of racks is usually worked with a lower flow temperature, in particular, the flow temperature of the cooling liquid in the rack cooling, again varying depending on performance and technical design between 10 ° C and 15 ° C, so that the housing walls of the rack can absorb heat caused by the individual modules. This usually results in a lower return temperature, which is usually not much above 20 ° C.

In the case of the technically more complex processor cooling, however, the cooling can take place at higher temperatures. In general, processors are designed for an operating temperature of up to 100 ° C, so that flow temperatures up to 60 ° C are sufficient to ensure sufficient process re-cooling. The return temperature for process recooling is usually quite high and can reach over 80 ° C.

According to the invention, waste heat is supplied to the computer system of the refrigerator in order to supply the refrigerator with drive energy.

There is thus no chiller used, which are driven by a mechanical compressor, but a chiller, which is operated with heat. Such chillers are also referred to as "thermal compressor". The invention makes it possible that the waste heat generated in the computer system is at least partially used for cooling the same. It can be achieved as significant energy savings.

Known refrigerators which can be operated with thermal energy are sorption refrigerators.

On the one hand, there are absorption chillers, of which in particular the water-lithium-bromide absorption chiller can be operated with flow temperatures from 80 ° C. These chillers are already available in large-scale industrial use with capacities of several thousand kW.

The use of an absorption chiller is particularly suitable for the processor cooling described above, since the return temperature of the cooling circuit reaches temperatures at which an absorption chiller can be operated. It must therefore be applied no or at least little additional heating power to operate the absorption chiller.

There are also adsorption chillers that are operated, for example, with zeolites or silica gel as the sorption medium. Such chillers have the advantage that they can be operated at significantly lower temperatures. As a rule, a flow temperature of 50 ° C is sufficient.

A disadvantage of the adsorption chiller is the discontinuous operation in which the adsorption medium is loaded and unloaded. An adsorption chiller can already be operated, for example, with the temperature of the exhaust air of a rack cooling.

The disadvantage of the necessary bridging of regeneration phases of an adsorption refrigerating machine can be reduced by using a plurality of sorption refrigerating machines, preferably adsorption refrigerating machines and / or an intermediate store, such that adequate continuous cooling can be ensured.

In particular, when using an air cooling, the use of operating on the principle of cooling by absorptive drying chiller, also known under the name Desiccant Cooling System (DCS) offers. Warm moist air is dried through sorbents and then moistened for adiabatic cooling. The water vapor saturated sorbents are regenerated by heating. Supply air can be cooled with it, at the same time the exhaust air is heated. The advantage of such absorptive drying is the relatively low cost and the low regeneration temperature, which is usually below 70 ° C.

In one embodiment of the invention, the racks and / or processors of the computer system are cooled with a liquid which is fed directly to the chiller to drive it. This embodiment of the invention is especially useful when looking at other components to increase the flow temperature for providing the Drive energy of the chiller is dispensed with. In particular, it is conceivable in processor cooling to interpose no further heat exchanger, but to supply the cooling medium directly to the heat exchanger of the chiller.

In an alternative embodiment of the invention, the chiller is connected via a heat exchanger with a cooling circuit of the computer system. This principle facilitates in particular the subsequent integration of the system in an existing cooling system.

According to the invention, a heat pump for increasing the flow temperature of the refrigerator is provided between the computer system and the refrigerator.

It is understood that the heat pump is also a chiller. For the purposes of the invention, a compression chiller is connected upstream as a heat pump, which is not supplied with heat as drive energy, but is dependent on an external energy source such as the power grid or a solar system. However, other physical principles for heat pumps are applicable, for. B. on the magnetocaloric principle working heat pumps.

Via a heat pump, the temperature of the return of the computer system can be brought to a value in which a downstream sorption refrigerator achieves good efficiency.

In this case, the cooling part, ie the evaporator of the heat pump is connected to the flow of the cooling part of the refrigerator. About the heating part, the condenser of the heat pump, the drive medium for the sorption chiller is preheated and simultaneously pre-cooled via the cooling part of the heat pump, the flow of the cooling part of the sorption chiller. Consequently, it is therefore also possible to use a sorption chiller with lower power at the same time.

In a further development of the invention, heat generated externally, in particular by a solar collector, is supplied to the chiller as additional drive energy. A solar system makes it conceivable that, depending on the climatic zone, a purely thermal operation of the cooling system is possible even without the use of photovoltaics. However, it is also conceivable to first supply the heat generated via a thermal solar collector to a heat pump together with the return of the computer system for further temperature increase.

In a development of the invention, the system comprises at least one, preferably two, buffer memories. In addition to the previously described use of buffer storage in conjunction with an adsorption chiller can be ensured by buffer memory and a sufficient emergency cooling in the event of failure of individual components.

Further, for example, a sufficient amount of drive fluid with the necessary temperature can be provided via a buffer memory in the inlet of the chiller, since depending on the configuration of the computer system, the return temperature or the heat output of the computer system can vary widely with fluctuating load.

Preferably, a buffer memory for storing cold fluid for cooling the computer system and a further buffer memory for storing a fluid is provided, that the chiller serves as a drive fluid.

In the case of using a further chiller to increase the temperature of the drive fluid of a sorption chiller, a buffer memory may also be arranged between the sorption chiller and the further chiller.

Next, the system, as provided in a development of the invention, have means for variable distribution of the cooling fluid within the computer system.

It is provided in particular to distribute the cooling capacity as needed depending on utilization within the computer system. To optimize the coolant distribution, as is provided in one embodiment of the invention, the system for cooling the computer system can be networked with the computer system itself. Thus, for example, it is conceivable that at least individual servers of the computer system pass on the respective utilization and / or the respective temperature to a control electronics of the cooling system via an interface, so that the cooling system is controlled not only flow and return temperature but load-specific. The advantage of such a control technique is due, inter alia, to the fact that additional cooling power is required even at a very early stage, namely immediately as the utilization of the computer system increases.

Compared with simpler control systems, which are controlled for example on the basis of the return temperature, so the cooling system can be operated at a lower utilization of the computing system with a significantly reduced power, without risking overheating of individual components in the event of a sudden increase in capacity due to the low cooling capacity supplied.

On the individual computers can be installed to control the computer system running in the background program for temperature monitoring, which passes this to the regulation of the cooling system with increasing cooling demand. As an interface in the context of the invention, for example, an already existing LAN connection can be used.

It is also conceivable remote monitoring and / or control of the cooling system via a network, in particular Internet-based.

In a preferred embodiment of the invention, the system comprises at least redundantly designed pumps for distributing the cooling fluid and / or a redundant cooling machine. At least for larger server farms, even if individual components of the cooling system fail, it is necessary to ensure a long-term supply of the cooling fluid over a longer period of time, for which buffer storages are generally insufficient.

For emergency cooling, for example, an additional conventional refrigeration compressor or a feed of cold tap water can be provided in the system.

In a further development of the invention, the system can also be integrated into an existing building air conditioning and / or hot water supply. Thus, for example, it is conceivable to use the process heat arising on a sorption cooling machine at least partially for heating the building and / or for supplying hot water.

In a preferred embodiment of the invention, the system is modular and comprises at least one cooling module, in which at least the chiller and an electronic control is arranged. In particular, it is provided to provide a module which consists of a housing with connections and to which in addition to a power supply, optionally the connection of the computer system via an interface, supply and return lines of the cooling of the computer system can be connected. Furthermore, the module preferably comprises connections for an external heat exchanger, is discharged via the process heat of the refrigerator.

The control of the system for cooling a computer system is also integrated in the module.

Furthermore, in a preferred embodiment of the invention, the module has at least one self-sufficient emergency power supply via which at least the drive of the pumps with which the cooling fluid is supplied to the computer system is ensured even in the event of a power failure. It is conceivable that at least also a control electronics of the cooling system is connected to the emergency power supply. For easier control is also conceivable that the pumps are controlled so that they continue to run with the control electronics off.

Alternatively, the emergency power supply of the cooling system can be ensured via an emergency power supply of the computer system, in particular via an uninterruptible power supply.

Computer systems usually have an uninterruptible power supply. Such uninterruptible power supplies of computer systems are usually cooled as well. It is therefore intended to use the cooling system for the uninterruptible power supply. An uninterruptible power supply usually comprises at least accumulators with which short-term interruptions of the mains voltage can be bridged. The uninterruptible power supply usually starts within a few milliseconds, so that only short-term disturbances of the voltage are compensated.

A computer usually also has telecommunications facilities such as connection modules to a telecommunications network. It is understood that the cooling system according to the invention, if necessary, also ensures the cooling of these telecommunication modules.

In a development of the invention, cascaded cooling systems are also provided, in particular for increasing the cooling capacity and / or for redundant design. In this case, a plurality of cooling systems is connected in series, such that the temperature of the cooling fluid is reduced in individual cooling stages. In this case, different chillers can be used, which are tuned to the respective cooling stage.

Furthermore, the invention relates to a method for cooling a computer system, in particular by means of a previously described system for cooling a computer system. The computer system is cooled with a sorption and it is supplied according to the invention of the sorption of waste heat of the computer as drive energy.

Description of the drawings

Brief description of the drawings

The invention will be described below with reference to the drawings 1 to 3 which show schematically illustrated embodiments of the invention will be explained in more detail.

1 shows an embodiment of the invention in which the components inserted into a rack are cooled by means of processor cooling and a sorption refrigerator.

2 shows an embodiment of the invention in which a heat pump is provided between a liquid-cooled rack and a sorption.

3 shows an embodiment of the invention, in which the rack is air-cooled and a heat pump is located between the computer and sorption.

Detailed description of the drawings

1 schematically shows a first embodiment of the invention, in which the system 1 for cooling a computer system 2 includes a processor cooling.

The computer system 2 is shown schematically here only as a single rack, which individual stacked modules 8th , which are formed, for example, as a server includes.

In this embodiment of the invention, the processors (not shown) of the computer system are cooled with a liquid. An advantage of processor cooling directly with liquids is the higher cooling efficiency compared to air- or liquid-cooled racks, resulting in a higher amount of heat that can be removed.

This is done via a flow 4 Cooling water at a temperature of less than 60 ° C supplied to the processors.

It is understood that in practice a plurality of racks is provided and that the system also comprises further branched lines, valves, pumps, etc., which are not shown in this schematically illustrated embodiment.

The coolant heats up to a temperature of up to 85 ° C and leaves the computer 2 over the return 5 , The return of the computer system 5 at the same time forms the flow of the heat of a sorption chiller 3 , The sorption chiller 3 can be designed in particular as an adsorption or absorption chiller.

A sorption chiller has a hot part 20 , a cold part 21 and usually a waste heat part 22 (Process heat). The refrigeration part 21 Energy is withdrawn and this the waste heat part 22 fed. Accordingly, it cools over the cold part 21 guided fluid, whereas on the waste heat 22 heated fluid heated. In the warm part 21 the thermal energy driving this process is fed via a drive fluid, this being via this hot part 21 cooled fluid, whereas that on the waste heat 22 heated fluid heated.

The over the return 5 the computer system 2 supplied heat serves as drive energy of the sorption and after heat dissipation the cooling part of the sorption 3 fed and leaves via a return, which at the same time the flow 4 the computer system 2 forms, the sorption chiller. For removing the process heat from the waste heat part 22 The sorption chiller is the process heat an external heat exchanger 6 supplied, the cooling capacity of a fan 7 is increased.

This ensures adequate heat dissipation of the system to the outside air. The cooling of the process heat can also be designed differently, shown is only the principle that a re-cooling takes place.

In an alternative embodiment, which is not shown here, is additionally between computer system 2 and sorption chiller 3 a heat pump is provided, with which the temperature of the flow of the sorption chiller 3 elevated.

By using the cooling fluid to provide the drive energy of the sorption chiller, a pre-cooling of the cooling fluid of the computer system is already achieved before it is further cooled in the cold part of the sorption chiller.

2 shows an alternative embodiment in which the computer 2 a rack with a heat exchanger 9 includes. The rack is thereby liquid-cooled. The cooling of the rack can be done in alternative embodiments of the invention (not shown) via other methods, for example by adapted to the housing walls heat exchanger. For a liquid-cooled rack, lower flow temperatures are typically required than with processor cooling. The advantage of rack cooling is the higher efficiency of the cooling, which allows a higher amount of heat to be removed compared to air-cooled racks. An advantage compared to Processor cooling is better handling. Thus, the computer system is less at risk of being damaged by leakage of the cooling fluid. It can also come in processor cooling in case of short-term failure of the cooling after a very short time to overheat and damage to the system.

It is understood that other energy from external sources, for example via a thermal solar collector can be supplied to the system.

At the in 2 illustrated embodiment of the invention is for the flow 4 the computer system 2 compared to a processor cooling a substantially low temperature, usually a temperature of 5 ° C to 15 ° C necessary to provide sufficient cooling of the arranged in the rack modules can.

As a rule, the coolant heats up in the heat exchanger 9 to a temperature which does not significantly exceed 25 ° C.

The return 5 the computer system 2 is therefore with a heat pump 10 connected, which is formed in the illustrated embodiment as a compression refrigeration machine.

The heat pump 10 includes a liquefier 11 , which forms the heating part and an evaporator 12 , which forms the refrigeration part. About the heat pump 10 and those from the return 5 the computer system 2 discharged coolant becomes the drive fluid for the sorption chiller to one for the sorption chiller 3 sufficiently high temperature and over the flow 14 the sorption chiller 3 , which at the same time as the return of the hot part of the heat pump 10 is formed, the sorption refrigerator 3 fed as drive energy.

About the return 13 the hot part of the sorption chiller 3 The cooled drive fluid is the heat part of the heat pump 10 returned and heated again. The necessary energy is the cooling liquid of the computer in the evaporator 12 withdrawn before this over the return of the evaporator, which at the same time flow 15 the cooling part of the sorption chiller 3 is, the refrigeration part of the refrigerator 3 fed.

The cooling circuit of the computer system 2 So it is with the cooling part of the heat pump 10 connected and the circulation of the drive fluid sorption chiller 3 is connected to the hot part of the heat pump. So the drive fluid of the sorption chiller becomes via the heat pump 3 brought to a sufficiently high temperature to be used in the hot part of the sorption as the drive energy, and at the same time the cooling fluid of the computer 2 in the cold part of the heat pump 10 Pre-cooled before putting it in the sorption chiller 3 is cooled even further.

The cooled to, for example, below 10 ° C coolant passes through the return of the refrigerant of the sorption 3 to the computer system 2 ,

It is understood that in this embodiment, further energy from external sources, for example via a thermal solar collector can be supplied to the system.

3 shows a further embodiment of the invention, in which the computer 2 is air cooled.

This is done via the fans 18 and 19 Air set in motion and over the flow 4 the computer system 2 fed.

About the return 5 The heated air is first through a first heat exchanger 16 led, which with the cooling part, the evaporator 12 , a heat pump 10 connected is. About the heat exchanger 16 Heat is removed from the air and in the hot part, the condenser 11 , the heat pump 10 the sorption refrigerating machine driving fluid is brought to a sufficiently high temperature to be used as the driving energy in the hot part of the sorption refrigerating machine.

Then the already pre-cooled air via a second heat exchanger 17 guided, which with the cooling part of the sorption 3 connected is. About the heat exchanger 17 The already pre-cooled air is brought to a sufficiently low temperature to return to the flow 4 the computing system to be supplied and to cool them.

It is understood that in this embodiment, further energy from external sources can be supplied to the system.

By means of the invention, the energy consumption required for cooling a computer system can be considerably reduced.

LIST OF REFERENCE NUMBERS

1

system

2

computer system

3

Sorption chiller, chiller

4

Advance of the calculating machine

5

Rewind of the calculating machine

6

heat exchangers

7

fan

8th

Module of the computer system

9

heat exchangers

10

heat pump

11

condenser

12

Evaporator

13

Return of the hot part of the chiller

14

Flow of the hot part of the chiller

15

Flow of the cooling part of the chiller

16

heat exchangers

17

heat exchangers

18

fan

19

fan

20

warm part

21

cold part

22

waste heat part

Claims (12)

System ( 1 ) for cooling a computer system ( 2 ), comprising a refrigerating machine ( 3 ), with which a fluid can be cooled, which the computer system ( 2 ) can be supplied, wherein waste heat of the computer system ( 2 ) of the chiller ( 3 ) is fed to the chiller ( 3 ) at least partially supplied with drive energy, characterized in that between the computer system ( 2 ) and the chiller ( 3 ) a heat pump ( 10 ) for increasing the flow temperature of the chiller ( 3 ), the return ( 5 ) of the computer system ( 2 ) first via the cooling part of the heat pump ( 10 ) and then via the cooling section of the refrigerator ( 3 ) is guided. System ( 1 ) for cooling a computer system ( 2 ) according to the preceding claim, characterized in that it is in the refrigerator ( 3 ) to a sorption and / or working on the principle of absoptive drying (DCS) chiller is. System ( 1 ) for cooling a computer system ( 2 ) according to one of the preceding claims, characterized in that racks and / or processors of the computer system ( 2 ) are coolable with a liquid, wherein the liquid of the refrigerator ( 3 ) can be fed to the drive. System ( 1 ) for cooling a computer system ( 2 ) according to claim 1 or 2, characterized in that the chiller ( 3 ) via a heat exchanger ( 16 ) with a cooling circuit, the computer system is connected. System ( 1 ) for cooling a computer system ( 2 ) according to one of the preceding claims, characterized in that externally generated heat of the chiller ( 3 ) can be supplied as drive energy. System ( 1 ) for cooling a computer system ( 2 ) according to one of the preceding claims, characterized in that the system ( 1 ) comprises at least one buffer memory. System ( 1 ) for cooling a computer system ( 2 ) according to one of the preceding claims, characterized in that the system ( 1 ) Means for the variable distribution of the cooling fluid within the computing system ( 2 ) having. System ( 1 ) for cooling a computer system ( 2 ) according to one of the preceding claims, characterized in that the system ( 1 ) redundant pumps for distribution of the cooling fluid and / or a redundant refrigeration machine ( 3 ) having. System ( 1 ) for cooling a computer system ( 2 ) according to one of the preceding claims, characterized in that the system ( 1 ) comprises a control electronics with an interface for connecting the computer system. System ( 1 ) for cooling a computer system ( 2 ) according to one of the preceding claims, characterized in that the system ( 1 ) comprises a cooling module, in which at least the chiller ( 3 ) and an electronic control are arranged. System ( 1 ) for cooling a computer system ( 2 ) according to one of the preceding claims, characterized in that the system ( 1 ) has a separate power supply for driving the pumps to distribute the cooling fluid. Method for cooling a computer system ( 2 ), in particular with a system ( 1 ) for cooling a computer system ( 2 ) according to one of the preceding claims, wherein the computer system ( 2 ) with a sorption chiller ( 3 ), wherein the sorption chiller ( 3 ) Waste heat of the computer system ( 2 ) is supplied as drive energy, characterized in that the flow temperature of the chiller ( 3 ) via one between the computer system ( 2 ) and the chiller ( 3 ) arranged heat pump ( 10 ), wherein the return of the computer system ( 5 ) first via the cooling part of the heat pump ( 10 ) and then via the cooling section of the refrigerator ( 3 ) to be led.

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