• 100% free cooling• lower cost• increased resilience

The largest energy consuming element apart from the IT load is the Compressor!!

TRADITIONAL chilled water system

SOLUTION – reduce or completely remove dependency on mechanical cooling

IT LoadElectrical lossesCooling

PUE = 2.0

The largest energy consuming element apart from the IT load is the Compressor!!

SOLUTION – reduce or completely remove dependency on mechanical cooling

IT LoadElectrical lossesCooling

PUE = 1.15

INDIRECT Adiabatic system

• Leverage natural cooling properties of outdoor air but keep contamination out

INDIRECT

• Decrease effective temperature of outdoor air in summer by increasing moisture content

ADIABTIC & EVAPORATIVE

INDIRECT adiabatic & evaporative

TYPICAL arrangement

Reproduced with kind permission of Nicholas Webb Architects and Digital Realty

EXCOOL winter operation

• Hot return air indirectly cooled by cold outdoor air

EXCOOL summer operation

• Warm outdoor air cooled by addition of moisture

EXCOOL extreme temperature

• Supply air cooling supplemented by ‘top-up’ DX pack

SECONDARY air at summer peak

UK design ambient condition

Adiabatic Process

Heat exchanger entering condition

35°C

25% RH

21°C

EXCOOL mechanical cooling thresholds

No mechanical cooling required if

outdoor air condition in blue zone

Global peak wet bulb temperatures

°C wb

35

30

25

20

15

For units running at full speed based on ASHRAE TC9.9 environmental envelopes and return temp 12°C above supply temp.

EXCOOL mechanical cooling thresholds

A

R24

THRESHOLDSA = ASHRAE Class 1 allowableR = ASHRAE recommended24 = 24°C supply temperature

Wet bulb temperature frequency - AnnualOSLO/GARDERMOEN, Norway (013840)

OPERATIONAL thresholds

Com

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ctiva

tion

poin

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mai

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n 24

°C s

uppl

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Adia

batic

acti

vatio

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int t

o m

aint

ain

24°C

sup

ply

-10 -5 0 5 10 15 20 25 30

Wet bulb temperature frequency - AnnualLONDON/HEATHROW AIR, United Kingdom (037720)

Wet bulb temperature (°C)

Com

pres

sor a

ctiva

tion

poin

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mai

ntai

n 27

°C s

uppl

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PUE – Power usage effectiveness

PUE = Total Facility Power IT Equipment Power

The average Power Usage Effectiveness (PUE) rating for data centres is 1.8, according to a survey of more than 500 data centres conducted

by The Uptime Institute

pPUE = IT Equipment Power + cooling system power IT Equipment Power

Typical Free cooling chiller system in London estimated pPUE = 1.20

City % Free Cooling Mech Cooling Hours pPUE

Recommended Allowable Recommended Allowable

London 100 100 0 0 1.025

Paris 99.95 100 4 0 1.026

Amsterdam 99.99 100 1 0 1.025

Madrid 99.95 100 4 0 1.027

Moscow 100 100 0 0 1.022

New York 97.91 100 183 0 1.034

Riyadh 99.95 100 4 0 1.066

• ‘Recommended’ and ‘Allowable’ refer to the environmental control envelopes recommended by ASHRAE TC 2011 Thermal Guidelines for Data Processing Environments

• Based upon 1MW IT load running at an annualised average of 75%• Data Source ASHRAE weather data viewer 4.0• Supply temp 24°C, return 36°C. Supply temp allowed to rise to 27°C (recommended) and 32°C (allowable).• Aisle containment in place maintaining a 12K ΔT between supply and return.• Resilience based on N+1 and pPUE calculated with all units running.• pPUE = (Cooling input power + IT power ) ÷ IT power

EXCOOL global efficiency

Key observation – PUE of ≤ 1.15 achievable in many locations

Additional EnergyMechanical cooling and Humidification

DIRECT air – viable alternative?

Contamination RiskForest fire in Moscow

shrouds city in smoke for several weeks in 2010.

Outdoor air systems in full re-circulation with 100%

mechanical cooling.Mechanical Cooling and dehumidification

Humidification

Silver Sulfide generated corrosion leading to copper creep and silver whisker growth ultimately resulting in server failure.**Randy Schueller – Dell – Creep Corrosion on Lead Free Printed Circuit Boards in High Sulfur Environments Oct 2007

Corrosion of Silver Soldered Joints due to Sulphur based gaseous contamination and high humidity/ temperature.*

• Full mechanical cooling support

required

Traditional chilled water and direct air

• 25% ‘top-up’ for extreme days

only. Runs for 4 hours per year

EXCOOL in Madrid

• No mechanical cooling required

– 100% ‘free’ cooling

EXCOOL in London

MECHANICAL cooling reduction

Based on ASHRAE TC9.9 recommended envelope and ASHRAE WD view 4.0 weather data.

• 60% reductionGenerator

• 70% reductionTransformer

• Reduced in sizeDiesel storage

ELECTRICAL infrastructure reduction

Relative to traditional chilled water and direct air systems.

CAPITAL cost saving

London 1MW Data Centre Cooling Approximate Capital Costs €

Values are approximate and for comparative purposes only. Costs may vary depending upon data centre design, equipment specification and selection and site conditions

Free Cooling Chillers Excool £-

£200,000.00

£400,000.00

£600,000.00

£800,000.00

£1,000,000.00

£1,200,000.00

BMS PointsWater StorageElectrical SystemPumps and pipesCRACsMain Plant

OPERATIONAL cost saving

Free Cooling Chillers

Excool £-

£20,000.00

£40,000.00

£60,000.00

£80,000.00

£100,000.00

£120,000.00

£140,000.00

£160,000.00

Annual MaintenanceRunning Costs

London 1MW Data Centre Cooling Approximate Operational Costs

Values are approximate and for comparative purposes only. Costs may vary depending upon local energy and labour costs. Running costs are based on £0.10 per kWh and £1.00 per m3 water.

• Auto drain down• Auto purge• Biological Filter• Anti scale system

Integrated System and

Software

• Annual consumption at 75% average load = 1500m3 per MW IT load in London. Equivalent to domestic consumption of 30 people

Water quantity

• No adiabatic cooling required in winter so no risk of freezing.

Frost control

• Integrity of water supply to be considered. Water store ideally buried to maintain ground water temperature.

Water storage

INTEGRATED water treatment

Approved by Legionella Control Association of Great Britain

• Inspect and clean at regular intervals. Site based engineers.

Air and water filters

• Calibrate, test and check controls and operation. Excool engineers every six months.

Controls

• Can be flushed. Normal operation results in washing due to adiabatic process.

Plate heat exchangers

• Sealed for life bearings may require changing every 5-10 years. Modbus interface allows the temperature and input power to be monitored.

Fans & Motors

MAINTENANCE

• Reduced Capex• Reduced Opex• Reduced Maintenance• Reduced Infrastructure costs• Reduced Build Costs

Lower Total Cost of

Ownership (TCO)

• Increase in available IT power • Improved resilience • Faster ROI – de-centralised

system• No Contamination Risk

Operational Improvements

CONCLUSIONS