EcoCoolingThe Application of Evaporative Cooling

in Data Centres and Server Rooms

Alan BeresfordManaging Director

Evaporative Cooling of Server Rooms

• Why is an alternative cooling method needed?• How an EcoCooling Computer Room

Evaporative Cooler (CREC) works• How a CREC meets the requirements of modern

IT equipment• How to size an installation• Control• Operation and Maintenance• Installation Examples

Why is an alternative cooling method needed?

• Electricity is a major cost• Cooling typically takes half of the electricity of a

data centre• It is believed the IT sector has a bigger carbon

footprint than air travel• Many data centres have exhausted the power

supply. Reducing cooling energy use releases power for servers!

• There are fears of legislation/taxation being applied to energy use in data centres

Power Usage Effectiveness

• Power Usage Effectiveness– The ratio of total power

consumed to the IT power– Most data centres in the UK

operate at 2.0 to1.5– With DX cooling it is difficult to

beat 1.6– Chilled water systems can

achieve 1.4

• The EcoCooling CREC has a .05 effect on PUE

• Data Centres and Server rooms using CREC’s typically have a PUE of 1.1 to 1.2

• The application of EcoCooling CREC’s can halve the energy use of many Data Centres

IT L

oad

Co

olin

g

IT L

oad

Typical

PUE 2.2

Co

olin

gIT

Lo

ad

Good

PUE 1.6

EcoCooling

PUE 1.1 to 1.2

How a CREC works

Da

ta R

ack

Damper

Constant flow and temperature

Evaporative Cooling

How a CREC works

Constant air flow`

Controlled temperature and

pressure

EcoCoolingCREC

Fresh air input to system

Exhaust air recycled

Attemperation damper

Evaporative cooling during

hot periods

Hot air exhausted to outside

How a CREC works

A 100kW server room needs 8.4m3/s

Use Q=mCpΔT to calculate mass flow

rate

Sizing and Energy – 100kW Example

This is the server load

Temperature rise through server

CREC energy use is less than 10% of DX

CREC energy use is 4.2 kW

Fridge energy use is 50 kW

Sizing and Energy – 100kW Example

A good DX system will achieve a COP of

2.0

A CREC uses 0.5 kW/m3s-1

218 tonnes carbon savings per year

Annual Cost Saving of £32,000

CREC system will use 37,000 kWhrs/yr

Sizing and Energy – 100kW Example

24/7 operation is 8760 hours per year

DX system will use 430,000 kWhrs/yr

Not 10kW but 8.4m3/s

This is the number of coolers required

No redundancy, N+1 or 2N

Sizing and Energy – 100kW Example

This is the flow rate of a CREC

The is the design capacity

Each grill is designed for .5m3/s

17 grills!

What are we trying to achieve?

• Conditions where servers and IT equipment is stable and reliable

• Lowest capital, energy and operating costs of cooling infrastructure

• Lowest possible environmental impact• Appropriate levels of security and resilience• Simplicity of operation and maintenance!

Temperature and Humidity Standards

Temperature

RH

0%

50%

100%

0C 10C 20C 30C 40C

Server Fan Energy

Condensation

Equipment Failure

Static

Cooling Costs

Tape Stability

CAF Development

EcoCooler Performance

Air off temperature will not exceed 23C in London

30C days are very rare

Red line is ambient

temperature

Blue line is cooled air from EcoCooler

In the North this will not exceed

20C

Temperature and Humidity Standards

0oC 5oC 10oC 15oC 20oC 25oC 30oC 35oC 40oC 45oC 50oC 55oC-5oC

10%

20%

30%

40

%

50

%

60

%

70

%

80

%

Manufacturer Specifications10-35C 5-80%RH

ASHRAE 2008 Class 1 Allowable15-32C 16.5CDP 20-80%RH

ASHRAE 2008 Class 118-27C 5.5-15CDP 60%RH

CIBSE19-23C 45-55%RH

Dry Bulb Temperature

RelativeHumidityEcoCooling Capability

EcoCooling is 100% temperature compliant and 99%

RH compliant

Close control is not required

ASHRAE Class 1 is a good guide`

Accepting this performance

can reduce the cooling energy

use by over 90%

Control

• PLC control system for up to 6 CRECS– Crouzet (Schneider)– Boolean logic analogue

control

• Control parameters– Fan speed– Cooling mode– Links to refrigeration

equipment– Fire alarm link– Suppressant dampers– Suppressant purge

• Ethernet and Modbus communication available

Control

All control is directed through the CREC

control panel whch can control up to six CREC’s

Control

Selectable menu items and set point adjustment

is by the push buttons and LED display

Control

External and internal temperatures (with

optional pressure) are constantly monitored

CREC speed and cooling mode is controlled

Fire alarm link disables CREC’s and enables

refrigeration equipment and closes suppressant

dampers

Control

C1 C2 C3 C4

Mains Water

Drain

DrainValve

Initiate Cooling Mode

Initiate water supplyDrain Water Supply

SP – 2CSP – 4CSP – 6C5C

Cooling Mode Disabled

SP

Water supply is automatically

drained for frost protection

Cooling mode is only enabled

when necessary

Ability to cope with very hot days

PowerSavings

Simple Redundancy

SimpleMaintenance

No F Gas Compliance Costs

Low cost spare parts holding

External Access for maintenance

Increase in available power

CarbonSavings

No internal space needs

Operational Advantages

Maintenance

3 monthly service

Service takes approximately 1hr-Clean pads-Clean insect screens-Clean sump-Run test sequence

Cooling pads have a lifetime >3yrs

Consignment stock of spare parts option

Cambridge University

0

20

40

60

80

100

120

140

Jul Aug Sep Oct Nov Dec Jan

kW

IT Load

Cooling Energy

EcoCooling

• Specialist designer and supplier of evaporative coolers

• Established in 2002• UK stock of coolers and all

spare parts• Patented processes for IT

cooling• Un-rivalled technical

expertise in all forms of cooling

• Sector leader in application of evaporative cooling in data centres

• Over 3000 EcoCoolers installed in the UK

Summary

• Modern IT equipment is robust and does not require “close” control

• An EcoCooling system can reduce data centre and server room cooling energy use and costs by over 90%

• EcoCooling CREC’s make a PUE of 1.1 possible with conventional buildings, racks and servers.