APPLICATION

IT Cooling Solutions Sustainable hybrid dry cooling of data centres

JAEGGI – The Original

Since 1929, JAEGGI has been engaged in the development, production and sale of heat exchangers. Since 1995 the company has been part of the Güntner Group, a worldwide established manufacturer of components for refrigeration, air-condition-ing technology and industrial applications with a total workforce of 2,600 people. Our production facilities in Europe, America and Asia secure us direct market ac-cess and spare parts service worldwide.

JAEGGI places economic efficiency and environmental protection on an equal foot-ing. Our products and services make an active contribution to lowering your oper-ating costs and conserving resources.

Our coolers are tested for hygiene conformity and aerosol emissions. The ISO 9001 quality management system, carried out by the Swiss Association for Quality and Management Systems SQS, guarantees our customers premium quality and maxi-mum reliability anywhere in the world.

All fluid cooling technologies for data centres and server rooms

For over 80 years, the Güntner Group has been manufacturing heat exchangers for refrigeration and air condition-ing. Our reliable and innovative products make us one of the industry’s leading component manufacturers. With our diverse technologies and our consulting expertise we can supply the optimal fluid cooler for every application. For IT cooling applications this means a high level of operational reliability plus a short payback period due to low operating costs.

Technologies

Güntner Group

dry sprayed adiabatic hybrid Multiple circuit coil

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Sustainable dry cooling for data centres

The growing number of computer applications, mobile data, internet services, cloud computing, etc., also increase the demands placed on data centres as regards both quantity (data storage, transmission speed, processing power) and qual-ity (efficiency, resource consumption, emissions).

And the energy consumption relating to cooling the data centre while in operation is already be-tween 30 and 50 %. This means that the elec-tricity consumed by data centres is responsible for around 2 % of global CO2 emissions – just as much greenhouse gas as the entire aviation sector. At the same time, the industry does have a considerable potential for reducing electrici-ty demand by investing in efficiency-enhancing measures on the infrastructure side. On average, 50 % of the electricity consumed by data centres is used for air conditioning, dissipating waste heat and maintaining an uninterruptible power supply (UPS).

Modifications in these areas can be carried out efficiently and without jeopardising the availabili-ty of the IT processes. And this can reduce both costs and CO2 emissions. This is where JAEGGI and its hybrid dry coolers offer future-oriented technology as their contribution to greener data centres.

Increased demand alongside a mandated reduction in CO2 emissions

Growing need for cooling

Cool

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More efficient use of energy CO2 emissions must be reduced

MAXIMUM EER

YEAR ROUND (PARTIAL PUE)

(ENERGY EFFICIENCY RATIO)

Success factors in data centre planning

REDUNDANCY

INFR

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(POWER USAGE EFFECTIVENESS)AN

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LOW pPUE ACHIEVABLE ALL LOW PUE ACHIEVABLE

SAVING WATER

EFFI

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2010 2020

Growing need for cooling

Cool

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More efficient use of energyCO

2 emissions must be reduced

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Efficient system design with refrigeration chillers

A typical application for free cooling is the pro-vision of cold water for cooling data centres and servers. This makes it possible to reduce the operating load hours of the refrigeration chillers, so saving a significant proportion of the energy costs.

Year-round low dry cooling temperatures ensure efficient operation of the refrigeration chillers and a high EER (COP).

Chiller operation

Operating a refrigeration chiller raises the thermal load to a higher temperature level and then uses the hybrid dry cooler in dry or wet operation to dissipate the waste heat to the environment. There is potential for increased efficiency primarily in the energy-efficient operation of the refrigeration chiller and the water-efficient and energy-efficient operation of the hybrid dry coolers.

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Efficient system design using free cooling

Free cooling can be used to cover a large pro-portion of the installation’s annual operating hours.

In this diagram, you see a conventional plant design that uses hybrid dry coolers (in free cooling operation) for the direct dry cooling of the servers.

Free cooling operation

In free cooling operation, the energy-intensive refrigeration chiller is switched off and the entire thermal load is dissipated directly to the environment via the hybrid dry cooler in dry or wet operation. There is potential for increased efficiency primarily in the water-efficient and energy-efficient operation of the hybrid dry coolers.

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Temperature requirements for data centres

Sufficient cooling in the data centre is essential to its survival. If the IT hardware is not reliably cooled, its availability can no longer be guaranteed and the equip-ment may even be physically damaged. To prevent this happening and to ensure high availability, it is very important to dissipate energy from the server rooms. However, aiming at temperatures that are too low expends a great deal of effort in cooling and dissipating energy to the environment, which is neither economi-cally nor ecologically sensible. The required level of dry cooling is determined primarily by the IT equipment and cooling technology used.

The latest edition of the 2011 ASHRAE Handbook – HVAC Applications recommends desirable temperatures for data centres categorised as classes A1 to A4 (see il-lustration below). The recommended temperature range for class A1 is 18 – 27 °C, and the permissible range goes up to 32 °C. The two illustrations below contain graphic representations of the recommended and per-missible temperature ranges.

Relative humidity

Clas

s A4

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Classes A1 – A4 Recommended

range

Dry bulb temperature in °C

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wat

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g of

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in °C

Illustrations: hx diagram for humid air showing the classes used in the 2011 ASHRAE Handbook – HVAC Application

Cambridge University, UK

Recommended range according to 2011 ASHRAE

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450

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-12 -6 0 6 12 18 24 30 36

-12 -6 0 6 12 18 24 30 36

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32°C

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Chiller HTKDRY

Heat source

24°C

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Chiller HTKWET

Heat source

24°C

23°C

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18°C

HTKDRYChiller

Heat source

24°C

23°C

17°C

18°C

HTKWETChiller

Heat source

Effects of temperature levels on energy and water consumption

In the illustrated system which is equipped with a refrigeration chiller and can also be operated in free cooling mode, the energy can, depending on the outside temperature, be dissipated to the environment directly via the dry cooler.

Annual temperature Frankfurt am Main | Data centre temperature = 18 °C

Annual temperature Frankfurt am Main | Data centre temperature = 32 °C

Free coolingHTK dry

Free coolingHTK dry

Free coolingHTK wet

Free coolingHTK wet

RM mode (HTK dry/wet)

RM mode (HTK dry/wet)

Free cooling operation

Chiller operationwith dryhybrid cooler

with dryhybrid cooler

with wethybrid cooler

with wethybrid cooler

Annual temperature variation showing the classes for the modes of operation

In the system in the example, with 1 MW cooling capacity, the annual temperature variation shown gives the tem-peratures up to which the indicated operating modes can be used. If the data centre needs extremely low tempera-tures, then the use of free cooling operation is very limited. The refrigeration chiller will already need to be activated when the outside temperature is low. The refrigeration chiller can save energy only with the lowest possible return temperatures from the dry cooler. If the temperature in the data centre is 32 °C, this system configuration can still be used in free cooling operation to dry cool the IT equipment, provided the outside temperature does not exceed 25 °C.

Energy consumption of refrigeration chiller

Energy consumption of dry cooler

Water consumption of dry cooler

Free cooling with dry cooling -

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Free cooling with evaporative cooling

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Operation of a refrigeration chiller with dry cooling

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Operation of a refrigeration chiller with evaporative cooling

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The structural diagrams show all possible operating modes for the entire dry cooling system.

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Economic impact of data centre temperature

Calculating the operating load hours for the year makes its impact on their distribution apparent. The proportion of free cooling mode increases as the data centre temperature increases.

Proportion of operating load hours spent in free cooling dry/wet/refrigeration chiller operation, depending on the data centre temperature

Free cooling dry

Data centre temperature in °C

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Free cooling wet

Refrigeration chiller operation

Location London (UK)

Data centre temperature 18 °C 32 °C

Free cooling dry 3 h 0.03 % 5,332 h 61 %

Free cooling wet 21 h 0.24 % 3,150 h 36 %

Refrigeration chiller 8,737 h 100 % 279 h 3 %

Energy consumption of the refrigeration chiller 498 MWh ‑98 % 9 MWh

Energy consumption of the dry cooler 58 MWh 2 % 59 MWh

Total water consumption 4,533 m3 66 % 7,520 m3

Total costs (at 0.1/kWh; €4/m3) €73,740 ‑50 % €36,937

When we calculate the operating costs for energy and water, we can also see the commercial effect of the data centre temperature. Increasing the data centre temperature to 32 °C would enable the operating costs for dry cooling to be reduced by 50 %. This reduces the total energy consumption by almost 98%.

High-yield investment

Saves money, saves resources

Unlike conventional cooling towers, choosing hybrid dry coolers from JAEGGI gives you a resource-efficient unit that rapidly pays for itself.

This system uses around 70 to 90 % less water than a conventional cooling tower, which represents a worth-while saving – particularly for such a long-term durable product.A representative comparison between a wet cooling tower and a hybrid dry cooler from JAEGGI was compiled on the basis of a system in use at a production facility in London, operating three shifts with a year-round con-stant load of 1,000 kW. In this system, the cooling water temperature was brought down from 38 °C to 28 °C.

During cooler periods or under partial load, the JAEGGI HYBRIMATIC control operates the coolers entirely dry, i.e. dissipating heat to the ambient air purely by convection. Only when dry operation is unable to achieve the required cold water temperature, does it automatically switch in

the wetting cycle. In this particular example, the switch point for dry operation is at an ambient temperature of 18 °C.

At the London site, the water consumption of the hybrid dry cooler over a period of one year (i.e. water lost to evaporation and used for blowdown at 3-fold concentra-tion) was 1,350  m3 with a wastewater volume of 450  m3. If a wet cooling tower had been installed instead, this would have consumed 15,693 m3 of fresh water and generated 5,231 m3 of wastewater. As you see, in this example, using hybrid dry cooling reduced the water consumption by over 90 %.

ConclusionPurchasing a hybrid dry cooler not only saves you enor-mous operating costs, it also protects the environment and our dwindling resources – of which water is also one. In this example, investing in the HTK had already paid for itself after 2 years

Water saved by a JAEGGI HTK compared to a conventional cooling tower

554,370 €

177,310 €

40,000 €

Cooling tower

JAEGGI HTK

years

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100%Kältemaschine [h]

Freecooling benetzt [h]

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Data centre cooling without compressor refrigeration

If the refrigeration chiller represents a substantial investment in the plant design and is a majorenergy consumer, alternatives are also interesting.

Which features may be of interest to planners? – Location of the installation Annual temperature variation – Data centre temperatures – Minimising heat transfer processes

Two possible options are briefly introduced here:

Cooling wall

The hybrid dry cooler is connected to the cooling wall directly, without an intermediate circuit. The cooling wall deals with cooling the data centre interior.

Advantages – No intermediate circuit – Lower temperature transfer losses – Higher circulation temperatures in the dry cooling circuit

Server rack backplane cooling

The hybrid dry cooler is connected to the water-cooled racks directly, without an intermediate circuit. The air entering the rack is heated by the IT equipment and cooled again before it leaves.

Advantages – No intermediate circuit – Lower temperature transfer losses – Higher circulation temperatures in the dry cooling circuit – Increases the free cooling potential

– Increases the free cooling potential – Low pressure drop Δp leads to lower fan power

– Very small region with higher air temperature (and only inside the rack)

– Very small regions with high air speed (and only inside the rack)

– No false floor needed

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Hybrid dry coolers – Plume-free – Minimal sound emission – Maximum power density – Coated heat exchangers – Low consumption of water and energy – Short payback period thanks to low operating costs

– Absolute operational reliability, even with high outdoor temperatures

– Achieves a PUE of < 1.22 – Can achieve cooling water temperatures that are lower than the ambient temperature.

– Calculation of the amortisation, taking into account:

Up-to-date climate data Annual temperature variation Load profile

Fans – Fan units with

industrial fans for low noise and high efficiency

standard motors with premium efficiency

or

EC technology

Transportation/bringing‑in

– Highly resistant to torsion – Unit up to 5.45 m long without lifting beam – Unit longer than 5.45 m with lifting beam

Hybrid dry coolers High Performance

Combination of dry cooling and evaporative cooling

Sophisticated equipment technology and high-quality materials

Proven system to maximise savings in operating costs

Maximum operational reliability

Long service life

HYBRIMATIC – Intelligent control saves operating costs – Monitors all important parameters – Trouble-free, efficient operation – Manages wetting water system – Reports errors and issues operating messages – Communicates with building management systems

– A number of bus systems are available – Optimised for water-saving operation

HYBRIMASTER control: – Controls multiple hybrid coolers installed in parallel for a high degree of energy efficiency and water savings

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thermowave plate heat exchanger

Compact, powerful heat exchangers between the primary and secondary circuit

No glycol-carrying pipes in the building or the server room

Compact, powerful plate heat exchangers – High level of energy efficiency due to small temperature differences

– Excellent fouling resistance due to high turbulence and smooth surfaces

– Highly fail-safe thanks to proven technology – All parts in contact with water are made of stainless steel

Easy to install and service – Compact construction – Easy cleaning – Easy maintenance

Wide range of applications – Capacity of 50 – 1000 kW – Various plate geometries – Optimised pressure drops

Member of the Güntner Group – Everything from a single source – Easy processing – Precise design

Primary circuit (water/glycol)Secondary circuit (water)

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SAP St. Leon RotSAP is a leading provider of business software that was founded in 1972, with headquarters in Walldorf (Germany) plus sales and development locations in over 50 countries around the world. The hybrid dry coolers are used for dry cooling the refrigeration chillers and for free cooling. In St. Leon Rot, SAP operates over 24 hybrid dry coolers with a total capacity of 30 MW.

Equinix AM3 Amsterdam With more than 95 IBX data centres in 31 major business centres, Equinix is one of the world’s leading providers of data centre services, connecting over 4,400 customers and partners worldwide. Equinix AM3 Science Park in Amster-dam uses an innovative concept based on 100 % water – without any chemicals or biocides – geothermal aquifer storage plus hybrid dry cool-ers from JAEGGI (HTK Hybrid High Performance). Equinix AM3 won thewon the Green Data Centre Award in 2012.

Data centre of a major international telecommunications company

This cloud data centre is currently the larg-est data centre in Germany and began op-eration in 2014. Cooling the server rooms calls for a capacity of 18  MW. 12 JAEGGI hybrid coolers of type HTK were installed for free cooling operation. Increasing the temperature of the cooling water and using hybrid cooling ena-bles the free cooling units to operate for nearly 8,000 hours per year without using the refriger-ation chiller.

References

xDC Swisscom WankdorfSwisscom’s Wankdorf data centre of is one of the most modern and efficient in the world. Its IT equipment oc-cupies a floor space of 4,000 m2, seven modules each consuming 600 kW, and reaches peak energy efficiency (PUE = 1.2) by virtue of its excellent efficiency, modular structure and the innovative cooling system that uses no compression refrigeration.

Year-round cooling is guaranteed using only free cooling with JAEGGI hybrid coolers. Part of the waste heat is also used to heat neighbouring residential properties.

JAEGGI provided the installation’s 8  HTK1.8/7.8 dry coolers with a total capacity of 6 MW, and is proud to be a part of this high-efficiency concept.

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JAEGGI Hybridtechnologie AGHirschgässlein 11CH-4051 BASEL

www.jaeggi-hybrid.eu

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