Applying Precision Air Conditioning Systems Canatal International Inc.

Introduction Application of Precision Air Conditioning Data Centers Switching Stations Co-Location Facilities

Topics of Discussion Servers / Switch Gear Temperature & Humidity Control Air Distribution Redundancy Alternating Cold Aisle, Hot Aisle Perforated Tile Capacity Design & Planning Stage Maintenance

Servers / Switch Gear Smaller, More Powerful Driven by semi-conductor capacity More transistors on a chip More power consumption per chip More heat generation

Servers / Switch Gear Published Power Rating may expect future upgrades, higher energy consumption and greater heat rejection Initial power consumption and heat generation can be lower

Available @www.ashrae.org, Item Number 90431, or D90431 New ASHRAE Document “Thermal Guidelines for Data Processing Environments” Equipment Environment Specifications Facility Temperature & Humidity Measurement Equipment & Facility Layout Equipment Manufacturers Heat & Airflow Reporting Available @www.ashrae.org, Item Number 90431, or D90431

“Thermal Guidelines for Data Processing Environments” Equipment Environment Specifications

“Thermal Guidelines for Data Processing Environments” Equipment Environment Specifications

ASHRAE Class 1 Operating Conditions

ASHRAE Class 1 Operating Conditions Increase Equipment Failures

ASHRAE Class 1 Operating Conditions Increase HVAC Energy Use

“Thermal Guidelines for Data Processing Environments” Facility Temperature & Humidity Measurement

“Thermal Guidelines for Data Processing Environments” Equipment & Facility Layout Recommended Airflow Protocol for Computer Equipment

“Thermal Guidelines for Data Processing Environments” Equipment & Facility Layout Recommended Airflow Protocol for Computer Equipment

“Thermal Guidelines for Data Processing Environments” Equipment & Facility Layout Recommended Airflow Protocol for Computer Equipment

“Thermal Guidelines for Data Processing Environments” Equipment Manufacturers Heat & Airflow Reporting

Server / Switch Gear 1U (1.70” H) Server Back View Front View

Server / Switch Gear 2U (3.50” H) Server Back View Front View

Server / Switch Gear 4U (6.80” H) Server Back View Front View

Server / Switch Gear 5U Server – Tower Configuration Back View Front View

Server / Switch Gear Back View Front View

Heat Density Trends Source: Uptime Institute

What is wrong with this picture?

What is wrong with this picture? 1b 2 3 4 5 2 2 1a, 1b Cold aisles. 1a has less airflow then 1b - WHY? 2 Hot aisles 3 Top of hot aisle (from right to left – warm to hot) 4 Insufficient cold air and recirculation from hot aisle to cold aisle 5 Mixed return air path

External re-circulation: Top 1/3 portion likely to have higher failure rate

Internal re-circulation: Add blanking panels to eliminate the problem

Positioning of PAC units Parallel or Perpendicular to aisles

Temperature Control Challenges Hot Spots / Hot Zones / Hot Room Uneven heat load on the floor space Fluctuating heat loads Initial low loads

Temperature Control Servers/Switches generate sensible heat Utilize Precision Air Conditioning Systems with high sensible heat ratios Unwanted dehumidification is a waste of energy and money

Humidity Control Independently operated units will fight - simultaneously humidify and dehumidify Wasting energy and money Units should work together as a Team

Air Distribution Raised Floor System Generally more flexible Easy to move perforated tiles Overhead System Ducted or Plenum Make the last length of duct flexible to enable movement of discharge grilles

Air Distribution Deliver Cool Air to the Heat Source Eliminate Short Circuiting Anytime air returns to the PAC without passing through heat generating servers, routers, switches etc.

Air Distribution Short Circuiting - Common Causes Obstructions to airflow Air Leakage Location of discharge grilles and perforated tiles

Air Distribution – Obstructions Raised Floor System Electric cable trays, especially with shallow floor heights Water damp

Air Distribution – Obstructions Practice Recommendations for Position Equipment Racks & Cabinets Power Distribution Unit (PDU) cables should run under the “Cold Aisles” Cable trays for telecom cablings should locate under the “ Hot Aisles” Cabinet should be aligned with one edge along the edge of the cold aisle floor tile Floor tile cuts should be no larger then necessary to minimize air pressure loss

Air Distribution – Obstructions Practice Recommendations for Position Equipment Racks & Cabinets Power Distribution Unit (PDU) cables should run under the “Cold Aisles” Cable trays for telecom cablings should locate under the “ Hot Aisles”

Air Distribution – Obstructions Practice Recommendations for Position Equipment Racks & Cabinets Power Distribution Unit (PDU) cables should run under the “Cold Aisles” Cable trays for telecom cablings should locate under the “ Hot Aisles”

Air Distribution – Obstructions Practice Recommendations for Position Equipment Racks & Cabinets Power Distribution Unit (PDU) cables should run under the “Cold Aisles” Cable trays for telecom cablings should locate under the “ Hot Aisles”

Air Distribution – Obstructions Practice Recommendations for Position Equipment Racks & Cabinets Cabinet should be aligned with one edge along the edge of the cold aisle floor tile

Air Distribution – Obstructions

Air Distribution – Oversized Openings Practice Recommendations for Position Equipment Racks & Cabinets Floor tile cuts should be no larger then necessary to minimize air pressure loss

Air Distribution – Oversized Openings

Air Distribution Obstructions Maximize Floor Height Floor height restricts air flow volume High airflow velocities under the floor can negate static pressure differentials and entrain air from above to below May need scoops

Air Distribution Obstructions

Air Distribution Obstruction Overhead System Light fixtures, overhead cable trays Equipment that is taller than the discharge plenum

Air Flow Obstruction

Air Distribution – Obstructions

Air Distribution – Obstructions

Air Distribution – Air Leakage Raised Floor System Behind the PAC unit Improper Wire/Cable openings - remove one tile to run wires Around the perimeter of room Adversely effects the under floor static pressure hindering the control of airflow

Air Distribution – Air Leakage

Cleanliness and Proper Vapor Barrier in Subfloor

What is the right distance from PAC to the 1st Rack

None-Direction Airflow Pressure = Static Pressure + Velocity Pressure

Perform Better

Air Distribution – Air Leakage Overhead System No shut off dampers on redundant units Back draft dampers or motorized discharge dampers with timers

Air Distribution – Airflow Pattern Raised Floor System Perforated tile quantity and layout Perforated tiles too close to the PAC 3 foot clearance above computer racks Drop ceiling = return air plenum

Air Distribution – Airflow Pattern

Air Distribution – Airflow Pattern

Air Distribution – Airflow Pattern Overhead System Discharge diffuser too close to the PAC Air discharge from one unit enters the return air of another

Air Distribution – Airflow Pattern

Redundancy N+1 PAC Units i.e. 20 ton load, three 10 ton units Only one pump on glycol/water loop Multiple feeds to PAC units, but only one breaker for all rooftop condensers

Redundancy of Airflow Can air reach each part of the room from more than one unit? If the answer is no, then N+1 may be negated

Alternating Cold Aisle, Hot Aisle Computer Equipment Air Flow Pattern In the front, out the back Racks face each other along one aisle Backs face each other on alternate aisle

Alternating Cold Aisle, Hot Aisle

Alternating Cold Aisle, Hot Aisle

Alternating Cold Aisle, Hot Aisle

Air Distribution – Airflow Pattern Raised Floor System Controlling the Return Air Drop ceiling = return air plenum

Air Distribution – Airflow Pattern

Cost Effective Solution

Cooling Capacity – One Tile Perforated Tile Cooling Capacity

Cooling Capacity – One Tile Directly dependent on the airflow volume deliver through each tile Air volume dependent on static pressure under the floor

Cooling Capacity – One Tile One 2’ x 2’ Perforated Tile Typical Airflow 600 cfm @ 0.10” w.c. 200 cfm @ 0.02” w.c. Thus, leakage and too many perf. tiles will reduce static pressure and reduce the ability to control air flow

Cooling Capacity – One Tile Maintain high sensible heat ratio AT 72˚F, 50%RH or 68˚F, 50%RH, excessive condensation occurs after a 17˚F temperature drop

Cooling Capacity – One Tile 17˚F

Cooling Capacity – One Tile Cooling Capability 600 cfm x 17˚F x 1.08 = 11,000 Btuh Airflow volume critical to cooling capacity

Cooling Capacity – Per Rack Four foot wide aisles 22,000 Btuh sensible cooling per two feet of aisle With racks on both sides of the aisle, the heat load is 3,200 Watts per two feet of racking

Downflow Front Discharge

Design & Planning Stage Capacity and placement of PAC Room Geometry Initial & final room layout Initial & final load Factors affecting air flow distribution Plenum static pressure Obstructions beneath plenum Configuration to prevent air mixing

Design & Planning Stage Mechanical system selection: Air / water cool Refrigeration/water piping layout Keep it simple Noise concerns: Local or remote compressor Condenser / condensing Energy factor Dual / Free Cooling NSB, increase of useable floor space Free cooling system Risk factor Chilled water /water cooled system

Maintenance Commissioning of basic systems Programming of controller Refrigeration, electrical, blower RPM, etc. Programming of controller Configure alarm responses Train End-user Follow Maintenance Program

Maintenance Common Deficiencies Dirty or blocked filters Undercharged DX systems Un-calibrated or damaged sensors Poor water flow, partially closed valves or other piping obstructions Chilled water supply temp. (49 - 54˚F)

Thank You