data center design guide featuring - utah...

Data Center Design GuidefeaturingWater-Side Economizer Solutionswith Dynamic Economizer Cooling

Presenter:Jason Koo, P.EngSr. Field Applications EngineerSTULZ Air Technology Systems

jkoo@stulz‐ats.com

Water‐Side Economizer Solutions

OutlineASHRAE Standards and Guidelines relative to Precision Cooling

– ASHRAE 127‐2012– CEC Requirements– ASHRAE TC 9.9 – 2011– ASHRAE 90.1 ‐ 2010

Air & Water‐Side Economizers

ASHRAE 127‐2012

New Test Standards• ASHRAE 127‐2012 Method for Testing for Rating Computer and Data

Processing Room Unitary Air Conditioners defines performance teststandards

• The purpose is to establish a uniform set of requirements for ratingprecision cooling equipment

• Significant changes in the 2012 edition1. Higher return air temperatures, thus increasing efficiency

• 75, 85, 95, 105 degrees F DB2. Higher chilled‐water entering temperatures3. A testing/rating procedure for equipment4. A testing/rating procedure for the newer technologies

a. Row based cooling systemsb. Containment systems

Raising return air temperature using containment• With a raised floor (Figure 1)

– Raised floor is pressurized with cold air from the precision cooling units

– Cold air passes through perforated floor tiles, taken into the servers, heated and exhausted into the contained hot aisle

– Hot air is directed back to the ceiling plenum, then returned to the CRAH units

• With a slab floor (Figure 2)– Utilizes server racks that have a top

ducted chimney connection– A CRAH with front discharge floods

the space with cold air, allowing the servers to take cold air in from the front

– Hot air is discharged out to the chimney and returned to the CRAH unit via a return duct or ceiling plenum

Update of CEC Requirements

On July 1st 2014• Adopting the SCOP requirements of ASHRAE 90.1‐2010 which are based

on the ASHRAE 127‐2007 test standard (75°F and 52° DP EAT’s)

• Requires 100% testing of a representative of each unit that will be offeredfor sale in the state of California

• Elimination of non‐adiabatic humidification and reheat

Adiabatic cooling provided (BTU/h)

Total KW/H per year*

Cost Per KWH

Annual Cost of

Electricity

Ultrasonic 2,095,200 799,973 x $0.11 $87,997

Feature Infrared Humidifier STULZ UltrasonicTechnology Infrared Ultrasonics

Capacity (lbs./hr.) 22 18

Energy Consumption (Watts) 9,600 585

Water Requirements Non‐conditioned city water

Demineralized water using RO and DI

Maintenance Requirements ½ hour to remove mineral buildup in pan

No cleaning of ultrasonic required

Humidification Improves Efficiency

*KWH based on 1.23 KW/Ton for air cooled chiller

HumidificationTechnology

Number of Humidifiers Required

Watts Consumed

Annual Hours Of Operation

KW/H per year Cost Per KWH

Annual Cost of

Electricity

Annual Savings

Infrared 98 x 9,600 x 3,725 x 3,504,480 x $0.11 x $385,493

Ultrasonic 120 x 585 x 3,725 x 261,495 x $0.11 x $28,764 $356,728

Humidification Energy Comparison

Free Cooling Energy SavingsHumidification

and Free Cooling Energy

Savings$444,725

Combined

STULZ Ultrasonic Humidifier

DRH –Direct Room Humidifier

• Mounts below the ceiling in a conditioned space• On wall or column with factory furnished mounts• Suspended from above in open space • Integral blower and washable filter • Absorption distance determined by RH of room

Ultrasonic Humidifier in Space

STULZ Ultrasonic Humidifier

DAH –Ducted Air Humidifier

• Mounts in moving air stream of AHU or ductwork• Multiple humidifiers assembled on factory rack system• Air velocity design similar to heating/cooling coils • Factory accessories for optimized airflow and mist control• Absorption distance determined by RH of airstream

Ultrasonic Humidifier in Duct

ASHRAE Standards and GuidelinesASHRAE TC9.9 2011• Allowance for increased delta‐

T across server equipment• Offers an opportunity to raise

the return air temperatures to the cooling equipment

• Current trend for maximum efficiency in the data center – isolate the hot return air

from the cold supply – prevent air mixing

• Opportunity to raise the delta‐T between the supply air temperature from the cooling equipment to the IT equipment and the return air temperature from the IT equipment to the cooling equipment

What Has Changed Inlet Air Temperature

Moisture Content

2004 Recommended (old)

68‐77.0°F DB 40% RH to 55% RH

2011 Recommended (new)

64‐80.6°F DB 41.9°F DP to 60% RH & 59°F DP

2011 Allowable (A1) 59‐89.6°F DB 20‐80% RH up to 62.1°F DP

Coil Calculations and Optimization• Higher return air

temperature to the CRAC/CRAH equipment increases cooling efficiencies

• Increase Entering Air (to CRAH)

– Improve Net Sensible Capacity

– Decrease CRAH Unit Power– Decrease Chiller Power– Mix and match to achieve

optimal conditions– More economizer hours,

lower PUE, and lower energy costs

ASHRAE 90.1 – 2010• Since data centers have been

identified to consume ~3% of the total energy produced in the U.S., the former process cooling exemption is gone.

• Water‐side economizers must meet 100% of the expected load with cooling towers when operating at or above 40°F dry bulb / 35°F wet bulb and with dry coolers when operating at or below 35°F dry bulb.

• Evolution of Measuring Efficiency– ASHRAE 127 – 2007 guideline for

Sensible Coefficient of Performance (SCOP)

– ASHRAE 90.1 – 2010 guideline for SCOP (used for this presentation)

– ASHRAE 127 – 2012 guideline for Net Sensible Coefficient of Performance (NSenCOP)

The DOE is mandating that all states adopt ASHRAE 90.1‐2010, or a more stringent standard, for new data center design and construction by October 2013.

Direct Free Cooling System, butcustomer provides dampersystem and filtration, andcontrols its operation.

Air Side Economizers

Outside Air & Moisture OperationWarmer / High Humidity Dampers close & the CRAC/CRAH revert to traditional operation

Within Proper Range Outside air is directly introduced through the dampers in the mixing box

Colder than Desired Dampers mix outside air & return air to achieve desired temperature

Air Side Economizers

Vertical and horizontal mixing boxes for air-side economizer options using floor-standing CRAC’s or CRAH’s

• CRACs or CRAHs with an integrated mixing box and damper controls provide direct free cooling

• Units attached to the top of a CRAC or CRAH in a vertical or horizontal position

• Pre-filter and freeze protection damper options

• Mixes outside and return air depending on outside air conditions

• Full economizer controls provided by the CRAC or CRAH

Air‐Side Economzer

Vertical & Horizontal Mixing Boxes

Air‐Side Economzer

Direct Air-Side Economizer • Outside air (less than supply air

temp) is directly introduced into the data center

Direct Adiabatic Cooling• The outside air is cooled with an

adiabatic system and directly introduced into the data center

Direct DX Cooling• The outside and/or return air is

cooled with a DX evaporator coil and directly introduced into the data center

Air‐Side Economizer

CyberHandler (AHU) with Direct Air Economizer, Direct Adiabatic Cooling, and DX for trim

Direct Air-Side Economizer • Outside air (less than supply air

temp) is directly introduced into the data center

Direct Adiabatic Cooling• The outside air is cooled with an

adiabatic system and directly introduced into the data center

Direct DX Cooling• The outside and/or return air is

cooled with a DX evaporator coil and directly introduced into the data center


CyberCon (Modular/Container) with Direct Air Economizer, Direct Adiabatic Cooling, and DX for trim

DX Cooling Section with Humidification

Ex. Nortec V‐Profile Evaporative Pad

• An option is to add an adiabatic pad for direct adiabatic cooling before the DX Coil

• DX Coil used for trim capacity

• Ultrasonic Humidifier used for humidification

DX CoilUltrasonicHumidifier


Indirect Air-Side Economizer• Outside Air (less than supply air temp) passes through an air-to-air heat exchanger

to indirectly cool the data center return air

Indirect Adiabatic Cooling• The return air is indirectly cooled via an air-to-air heat exchanger that has an

adiabatic spray applied to it


CyberHandler with Indirect Air Economizer, Indirect Adiabatic Cooling, and DX for trim Indirect Adiabatic

Cooling Module

DX CRAC with Economizer Coil and Condenser Loop• Used with the following Water‐Side

Economizers:– Traditional Economizer Cooling– Variable Economizer Cooling– Evaporative Tower Economizer

Cooling

Types of Water Side Economizers

• DX Economizer Solutions– Traditional Economizer– Variable Economizer– Evaporative Tower Economizer

• CW Economizer Solutions– Dual‐Source Chilled Water

Economizer– Dynamic Economizer Cooling

• Standard• Optimized

Traditional Economizer Cooling Comparison• Traditional Economizer

Cooling– Constant fan speed dry

cooler • fans cycled on and off based

on fluid temperature

– Constant speed pumps– Water/glycol cooled free

cooling CRACs • DX cooling coil and

water/glycol free cooling coil

• Comparison of a CRAC to a CRAC with Free Cooling Coupled with a Constant Speed Fan Dry Cooler– Baltimore, MD– Salt Lake City, UT (4,500 ft

altitude)– Portland, OR

Variable Economizer Cooling Comparison• Variable Economizer Cooling

– Variable fan speed dry cooler

• fan speed controlled based on fluid temperature

– Variable speed pumps • controlled based on fluid

temperature– Water/glycol cooled free

cooling CRACs• DX and water/glycol free

cooling coil

• Comparison of a CRAC to a CRAC with Free Cooling Coupled with a Variable Speed Fan Dry Cooler– Baltimore, MD– Salt Lake City, UT (4,500 ft


Evaporative Tower Economizer Cooling Comparison• Evaporative Tower

Economizer Cooling– Closed loop evaporative

cooling tower • Controlled based on fluid

temperature

– Constant speed pump– Water/glycol cooled free

cooling CRACs• DX and water/glycol free

cooling coil

• Comparison of a CRAC to a CRAC with Free Cooling Coupled with an evaporative cooling tower– Baltimore, MD– Salt Lake City, UT (4,500 ft


Comparison of DX Economizer Cooling% Reduced Energy• Baltimore MD

– Traditional Economizer Cooling verses DX Cooling ‐13%

– Variable Economizer Cooling verses DX Cooling ‐31%

– Evaporative Cooling Tower Economizer Cooling verses DX Cooling ‐32%

Dual‐Source Chilled Water Economizer Cooling• Dual‐Source Chilled Water

Economizer Cooling– Evaporative cooling tower and

pump• controlled based on fluid

temperature– Air‐Cooled Chiller and pump

• controlled based on fluid temperature

– CRAH units• dual circuited interlaced chilled

water cooling coil

• Comparison of a CRAH Coupled with an Air‐Cooled Chiller to a CRAH with Dual Coils Coupled to an Air‐Cooled Chiller and Evaporative Cooling Tower– Baltimore, MD– Salt Lake City, UT (4,500 ft


Dynamic Economizer Cooling (DEC)• A Dynamic Economizer Cooling

(DEC) system (state‐of‐the‐art water‐side economizer solution)– Evaporative cooling tower– Air‐ cooled chiller– Cooling tower and chiller pumps– Control mixing valves– CRAH units

• Required cooling fluid temp < ambient conditions = operates in the cooling tower mode

• Required cooling fluid temp > ambient conditions = operates in the “chiller assisted cooling©” mode

• System minimizes hours of chiller operation and optimizes opportunity for economization

Warm Water Cooling

Power Usage Effectiveness (PUE)Evaluating Power Usage Effectiveness• Power Usage Effectiveness (PUE)

– Measurement of data center efficiency (by The Green Grid)

• PUE = (IT Load + Total Power) / IT Load– IT Load is the effective processing equipment power of the data center– Total Power includes security, cooling, lighting, fire monitoring, etc.

• Industry Benchmarks– PUE < 1.6 considered very good– PUE < 1.2 is state‐of‐the‐art

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