data center free cooling use of heat wheel tech

BRUNS-PAKData Center Design/Build Solutions

June 5, 2012

Data Center CoolingThe use of “Heat Wheel” Technology

Website: www.bruns-pak.com

Data Center w/Advanced Heat Wheel Technology Deployed

In 2011, BRUNS-PAK deployed a state of the art data center for a global Fortune 100 company utilizing advanced Heat Wheel technology as a major source of „free cooling‟.

Project Details:Projected

mechanical

efficiencies

PUEm = 1.15

Greenfield site Located in Northwest US

Tier IV Data Center & Infrastructure

180,000 FT2 Bldg Phase 1/55,000 FT2 Raised Floor

4,050 kW UPS Phase 1 /10,800 kW Ultimate (2N)

10MW Generation Phase 1 /24MW Ultimate (2N)


Data Center w/Advanced Heat Wheel Technology Deployed

The buildings energy conservation features include:

Heat wheel technology that provides approximately 7,450 hours of free cooling and 1,280 hours of partial free cooling.

Rooftop HVAC units provide outside partial and full free cooling when outside conditions permit.

Water cooled compressorized CRAC units are equipped with free cooling coils to provide free cooling when outside conditions permit.

Lighting system controlled by either the card access system or by motion sensors.

Trees and plants indigenous to the area that eliminate the need for an irrigation system.


What is a “Heat Wheel”?

A “Heat Wheel” also known as a rotary air-to-air energy exchanger, or rotary enthalpy wheel is a revolving cylinder filled with an air-permeable medium usually made of a non-corrosive, aluminum, honeycomb material having a large internal surface area.

Source: ASHRAE


How does a “Heat Wheel” work?

Adjacent supply and exhaust airstreams each flow through half the exchanger typically in a counter-flow pattern to recover heat only (sensible) or total heat (sensible plus latent).

Source: ASHRAE


Traditional use of “Heat Wheels”

Used for decades in ventilation air-conditioning systems

SOURCE: Illustration courtesy of XETEX


Benefits of Traditional “Heat Wheels”

“Pre-warm” outside air utilizing indoor conditioned air to reduce heating energy.

“Pre-cool” outside air utilizing indoor conditioned air to reduce cooling energy.

Reducing heating and cooling energy allows the ability to increase ventilation rates and improve overall indoor air quality, if desired.

Removes outdoor airstream moisture in the summer. Note: Additional moisture removal through alternate source likely required.

Adds some moisture to outdoor airstream in the winter. Note: Additional moisture through alternate source likely required.


Return Air (RA)(75F DB, 63F WB)

Exhaust Air (EA)(89F DB, 73F WB)

Supply Air (SA)(81F DB, 68F WB)

Outside Air (OA)(95F DB, 78F WB)

Example of Traditional “Heat Wheel” Performance - Summer

Outside air is directly supplied into the space and is “pre-cooled” by the return air which is directly exhausted.

Enthalpy Wheel






Example of Traditional “Heat Wheel” Performance - Winter

Enthalpy Wheel

Outside air is directly supplied into the space and is “pre-warmed” by the return air which is directly exhausted.


“Heat Wheel” Technology in Data Centers

The same principles of traditional “Heat Wheel” technology are applied, except:

Sensible only “Heat Wheel” is utilized. “Heat Wheel” is arranged with the outside and

inside airstreams separated.

Source: Illustration courtesy of Kyoto Cooling


Benefits of “Heat Wheel” Technology in Data Centers

More efficient means of “free cooling” than direct airside and waterside economizing.

Separated airstreams minimize contaminates and humidity exposure associated with direct outside air systems.

Minimizes make-up water consumption and water treatment associated with evaporative cooling systems.

Potential reduction in overall building footprint. Cooling demand can be supplemented with 100%

air-cooled/DX during extreme climate conditions, eliminating the need for a conventional chilled water system. Note: air-cooled/DX circuit is integral to unit.



ASHRAE Standards developed in conjunction with IT hardware manufacturers.

2008 Version

Low End Inlet

Temperature

64.4° F DB

High End Inlet

Temperature

80.6° F DB

Low End Moisture 41.9° F Dew Point

High End Moisture 60° RH & 59° F Dew Point

ASHRAE TC 9.9 Standard allows more hours of “free-cooling” regardless of the technology used.



Bin Data (8760 hrs) for New York City with a supply air temperature set point of 73F DB and a return air temperature of 95F DB:

6526 hours of 100% “free cooling”. 2198 hours of partial “free cooling” (i.e. simultaneous

“heat wheel” and supplemental mechanical cooling operation).

36 hours of 100% mechanical cooling.

Source: Data courtesy of Kyoto Cooling






Example of Sensible “Heat Wheel” Performance

Sensible Wheel

73F (SA) - 68F (OA) = 5F Approach to achieve 100% “free cooling”

Outside and inside airstreams are separated. Recirculated return and supply air is “pre-cooled” or “cooled” by the outside air, then directly exhausted to atmosphere.


Projected Mechanical Efficiencies PUEm = Mechanical Load

IT Load

Cooling Type Hot & Dry Cold & Dry Marine Hot & Damp

Refrigeration Process

(baseline) .60 .60 .60 .60

Baseline with direct

airside economizing .22 .15 .15 .23

Baseline with water-

free cooling .23 .23 .23 .26

Heat Wheel – Single

Cell .22 .08 .10 .17

Source: Data courtesy of Uptime Institute


Projected Mechanical Efficiencies PUEm = Critical Load + Mechanical Load

Critical Load


“Heat Wheel” Technology Applied in Data Centers

Some means of “hot-aisle” containment is recommended.



900kW roof-mounted Heat Wheel unit



900kW roof-mounted Heat Wheel units


NICHOLAS SAPIASenior Mechanical Engineer: BRUNS-PAK

PROFESSIONAL EXPERIENCE

Mr. Sapia has twenty years of experience in data center

projects. His experience ranges from evaluation of existing

facilities through coordination of design requirements for

highly technical projects. Mr. Sapia’s vast knowledge of

mechanical concepts makes him a valuable asset in

interpreting mission critical facility needs and alternatives.

Years of Experience: 20

Areas of Specialization:

Evaluating of existing facilities

through coordination of

design requirements for

highly technical projects,

redundancy concepts

Education:

A.A.S. Mechanical

Engineering Technology

B.S. Mechanical Engineering,

Train Air Conditioning, Air

Conditioning & Air

Distribution

Professional Membership:

ASHRAE

National Fire Protection

Association

data center free cooling use of heat wheel tech

Technology

heat wheel work

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rotary air

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f wb75f db

f wb72f db

f wb enthalpy wheel

simultaneousheat wheel