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Efficiency of Data Center cooling

Comparison of data room layouts and cooling systems

Bohumil Cimbal Product manager for Cooling Systems in CONTEG Company

Objective

• What DC arrangement is preferred?

• What is the requested cooling capacity?

• What temperatures in DC?

• How to increase Cooling efficiency?

Basic questions between investor and cooling designer

Content

• Datacenter as a heat source

• Cooling effectiveness

• Methods to increase effectivity

• DC room layouts and cooling systems

• Case study comparison

Data center cooling

Data center cooling

Increasing effectivity

• Measure and calculate efficiency awareness is a good start

• Application of power saving components fans, compressors, pumps, EC motors, etc.

• Use of sophisticated logic control software, communication of all parts in system, free-cooling, pressure control, etc.

• Set the correct temperatures air, water, refrigerant

Data center components Power consumption

TOTAL FACILITY POWER • Power delivery components (UPS,

generators, PDUs, batteries, and distribution losses external to the IT equipment)

• Cooling system components (chillers, air conditioners, pumps, and cooling towers)

• Compute, network, and storage nodes • Other miscellaneous component loads

(lighting, cleaning...)

IT EQUIPMENT POWER • Load associated with all of the IT

equipment • Computer, storage, and network

equipment • Supplemental equipment (monitors,

and workstations/laptops) used to monitor or otherwise control the datacenter

Power usage effectiveness

Power usage

effectiveness

Power usage effectiveness

Ideal Temperature in DC

Different points of view

IT equipment Comfort x Cooling Energy Efficiency

2011 Thermal Guidelines for Data Processing Environments – Expanded Data Center Classes by Technical Committee 9.9

New ASHRAE Classes 2011

Ti = 18 – 27°C ϕ = 30 - 60%

From IT point of view

Ideal Environment in DC

Ideal Temperature for IT

Server power consumption increases at higher ambient temperatures

Ideal Temperature for IT

the colder the better...

From Energy point of view

• Higher capacity of heat exchanger

• Thermal losses to the surround of DC

• Friendly compressor circuit conditions

• Higher efficiency of cold source

• Long free-cooling utilization

Benefits of higher temperature: Air temperature

increase

AC energy savings

1 K 4 %

2 K 8 %

3 K 12 %

4 K 16 %

5 K 20 % Source: Schweizer Bundesanstalt für Energiewirtschaft

Ideal Temperature in DC

Ideal Temperature in DC

Temperature impact on Cooling capacity (kW)

Return air Temperature

Water temperature

6/12 °C 10/16 °C 12/18 °C 15/21 °C

45 °C 81,8 72,4 67,7 60,7

40 °C 70,1 60,7 55,9 48,9

35 °C 58,3 48,9 44,2 37,1

30 °C 46,5 37,1 32,4 25,3

25 °C 37,1 27,7 23,0 15,9

Ti = 25°C Ti = 18°C

22% annual energy consumption difference

Ideal Temperature in DC

the hotter the better...

Hot and Cold Air Separation

Right conditions for computers + Maximal energy efficiency

Blanking panels and Separation frames

BLANKING PLATES

SIDE VIEW

Racks in open aisle

Not enough air

Too much air

Impossible to keep steady Servers change the air-flow continually

Optimal air flow

Mechanical Air Separation

The only possibility !

with air flow control

Plenum Feed With Room Return

Modular Closed Loop w. In-row Units

Cold aisle Containment w. Top cooling

Room Feed with Plenum Return

Cold aisle Containment w. Plenum Feed or In-row

Closed aisle Containment w. In-row Units

Data Center Room Arrangements

Data room Cooling systems

Comparison CRAC x In-Row x Topcooling

DC arrangement

Cold and Hot Aisles

CRAC = Computer Room Air Conditioner

Air path length

CRAC solution

• Cold air delivered under floor • Long way to servers

In-Row Air-conditioning units integrated into rows of racks

Air path length

In-ROW solution • Deliver cold air where required –

front of servers

Top cooling Air-conditioning units on top of racks

Air path length Topcooling solution • Deliver cold air where required –

front of servers

Temperature zones

In-ROW solution • Easy to plan different power and

temperature zones

CRAC solution • Only one temperature in all zones

in one room

Easy future enlargement In-ROW solution • Possibility of DC enlarging in steps

- minimizing initial investment

CRAC solution • Big initial investment • Low initial efficiency

Basic features comparison

CRAC In-row Top

cooling

Short air path to servers Easy to plan different power and temperature zones DC enlarging in steps - minimizing initial investment Open or Closed Architecture Cold or Hot Containments Technical service out of DC room Water in DC room Total power consumption of indoor units

Financial effect:

1. Floor area savings 2. Energy savings

- 16 racks 600mm, depth 1000mm, height 42U - contained cold aisle - 35°C in hot zone, 25°C in cold zone - Chilled water system (10/15°C) - heat load 6kW/rack (total demanded cooling capacity 96 kW) - requested redundancy n+1

Example:

Case study

• 3 CRAC units • cooling capacity 53 kW • air flow 9.000 m3/h • dimensions 950 x 900 mm • consumption 1,8 kW

• Occupied floor area = 2,6 m2

• Total consumption 3,6 kW (2 running units)

CRAC (CW)

• 6 in-row units • cooling capacity 21 kW • air flow 3800 m3/h • dimensions 300 x 100 mm • consumption 0,77 kW max

(0,3 kW at capacity 96/6=16 kW per unit)

• Occupied floor area = 1,8 m2

• Total consumption 1,8 kW (6 low-speed running units)

In-Row (CW)

• 4 Topcooling units • cooling capacity 38 kW • air flow 7.700 m3/h) • dimensions 2400 x 600 mm • consumption 0,7 kW max

(0,2 kW at capacity96/4=24 kW per unit)

• Occupied floor area = 0 m2

• Total consumption 0,8 kW (4 running units)

CoolTop (CW)

Case study

• 3 CRAC units • cooling capacity 53 kW • air flow 9.000 m3/h • dimensions 950 x 900 mm • consumption 1,8 kW

• Occupied floor area = 2,6 m2

• Total consumption 3,6 kW (2 running units)

CRAC (CW)

• 6 in-row units • cooling capacity 21 kW • air flow 3800 m3/h • dimensions 300 x 100 mm • consumption 0,77 kW max

(0,3 kW at capacity 96/6=16 kW per unit)

• Occupied floor area = 1,8 m2

• Total consumption 1,8 kW (6 low-speed running units)

In-Row (CW)

• 4 Topcooling units • cooling capacity 38 kW • air flow 7.700 m3/h) • dimensions 2400 x 600 mm • consumption 0,7 kW max

(0,2 kW at capacity96/4=24 kW per unit)

• Occupied floor area = 0 m2

• Total consumption 0,8 kW (4 running units)

CoolTop (CW)

Case study

Financial effects:

1. Floor area savings

Floor area per unit Number of units

Occupied floor area Floor area price Financial loss

(m2) (pcs) (m2) (€/m2/year) (€/year)

Top cooling 0 4 0 10 000 0

In-Row 0,3 6 1,8 10 000 18 000

CRAC 0,9 3 2,7 10 000 27 000

Expected price of one footprint (0,6m2) is 500€ per month.

Case study

Financial effects :

1. Energy savings Indoor units

consumption Number of

units Annual power consumption

Energy price Annual costs

(kW) (pcs) (kWh) (€/kWh) (€/year)

Top cooling 0,2 x 4 = 0,8 4 7008 0,15 1 051

In-Row 0,3 x 6 = 1,8 6 15768 0,15 2 365

CRAC CW* 0,7 x 3 = 2,1 3 18396 0,15 2 759

CRAC CW** 1,8 x 2 = 3,6 3 31536 0,15 4 730

* Redundant units are working (partial operation). ** Redundant units are stand-by.

Case study

0

5000

10000

15000

20000

25000

30000

Top cooling In-Row CRAC

Annual savings (€)

Summary

• DC concept Business plan in time, sizes, capacities

• Cooling design cooling system, CFD simulation, critical situations, TIER classes, safety points

• Building process product quality, piping system, monitoring

• Operation air separation, temperature setting, efficiency tracing

Dipl.Ing. Bohumil Cimbál

B.Cimbal@conteg.cz

www.conteg.com

Thank you for your attention