Cleanroom Energy Benchmarking Results

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Energy Benchmarks

• Goal
• Identify Energy Efficiency Opportunities in
  Cleanrooms Through Comparison of Benchmark Data

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Cleanroom Energy Benchmarking

• In California many industries rely on Cleanrooms

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Why Benchmark High-tech Buildings?

• From PGEs perspective
• PGE saw that the market was large and growing.
  In California
• 9400 GWH in 1997 (all high tech buildings)
• 4.2 million sq. ft. of operating cleanrooms
• Semiconductor and Biotech exhibited high growth

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Why Benchmark Cleanrooms?

• Owners perspective
• Cleanroom owners and facility engineers saw an
  opportunity to determine their energy end use,
  compare their efficiency to others, and
  potentially find efficiency improvement
  opportunities or uncover operational problems.

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Why Benchmark Cleanrooms?

• From a public goods perspective
• Under-served Market Emphasis on product
  rather than cleanroom
• Explore some Myths
• Energy is not a controllable expense
• We already considered efficiency
• Of course its efficient, we just built it.
• California would like to keep high-tech
  companies in the state
• And the usual save the planet reasons

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What we hope to accomplish

• Identify energy efficiency opportunities
• Integrate current best practices into operation
  and future design
• Research new approaches and technologies
• Reduce electrical demand to improve reliability
  and room for growth
• Apply lessons learned in California cleanrooms in
  other regions and other building types

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Benchmarking Process

• General plan informs participants
• Enlist Benchmarking participants
• Site specific plan developed
• On-site measurement and data collection
• Draft site report
• Final participant report and anonymous version
• Data and results entered in data base and
  summarized on web site

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Metrics

• Ability to compare performance regardless of
  process
• Focus on system efficiency rather than production
  efficiency

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Cleanroom HVAC metrics

• Recirculation air system cfm/kW
• Make-up air system cfm/kW
• Exhaust system efficiency cfm/kW
• Cleanroom air changes ACH/hr
• Air velocity in cleanroom - ft/sec

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Central Plant metrics

• Chiller efficiency kW/ton
• Cooling tower efficiency kW/ton
• Condenser water pump efficiency kW/ton
• Chilled water pump efficiency kW/ton

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Vision - an Energy BenchmarkData Base

• Anonymous reporting
• Comparison of similar class systems
• Comparison of components
• Comparison of overall facility
• No production metrics
• Sufficient data to identify best practices

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Cleanroom Benchmarking

• Some Results and observations to date

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Energy End Use
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Energy End Use
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Process Related Efficiency Issues

• Energy intensity varies greatly depending upon
  the process in the room
• Estimating process (heat) loads during design is
  a challenge so HVAC systems are often oversized
• HVAC equipment sized and controlled appropriately
  operates more efficiently
• Benchmark data can help determine realistic
  design loads to integrate into future projects
  for similar processes
• It is difficult to compare process energy
  efficiency unless nearly identical processes are
  occurring

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Process Loads
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Energy Intensive systems

• Recirculation of air in cleanrooms

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Recirculation Air Comparison
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Recirculation Systems Design vs. Measured
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• Why are Design Efficiencies less than Measured
  Efficiencies?
• Design efficiency is generally understated
  because larger power consumption (kW) is
  generally assumed. (nameplate vs. actual)

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Benchmarks as Design Criteria

• Idea! As a building owner,
• Why not specify a system efficiency?

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Recirculation Air Comparison
System Performance Target
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What is the cost impact?
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Fan-Filter Standardized Reporting

• LBNL and the Industrial Technology Research
  Institute (ITRI) in Taiwan are advocating a
  standard test procedure for fan-filter units
• The Air Movement and Control Association (AMCA)
  is organizing member companies to develop such a
  standard

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Make-up Air Comparison
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Make-up Air System Considerations

• Efficiency is influenced by

• Right sizing exhaust and pressurization
• Resistance of make-up air path
• Adjacency of air handler(s)
• Air handler face velocity
• Duct sizing and layout
• Fan and motor efficiency
• VFD controls

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Make-up Air Design vs. Measured
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Why is make-up air system efficiency lower?

• Retrofitted systems with less than optimal
  configurations
• High face velocity air handlers (due to space
  constraints or just inefficient design)
• Older less efficient equipment (motors, fans)
• Resistance due to heating and cooling coils,
  filters, etc.
• Duct sizing and layout

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Air-Change Rate Comparison
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Air Change and Velocity Observations

• Wide variation
• All processes had acceptable yields (so why do
  some get by with less airflow?)
• All cleanrooms were certified
• Some velocities exceeded (and some were below)
  IEST recommended ranges
• IEST provides recommendations based upon
  historical adequacy not science based
• Air velocity reduction and ceiling filter
  coverage are efficiency improvement opportunities

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Chilled Water Systems Comparison
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Chiller Comparison
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Chilled Water System Observations

• Wide variation in overall efficiency

• Surprise! Name plate chiller efficiency is
  different than measured
• Pumping energy can be significant over pumping
  sometimes occurs
• Chiller performance dominates
• Water Cooled chillers are more efficient

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Chilled Water System Resources

• Existing efficiency information for chilled
  water plants is under-utilized.

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Chilled Water System

• PGEs CoolTools
• http//www.hvacexchange.com/cooltools/

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Non-energy benefits of Benchmarking

• Operational problems revealed
• Controls
• Setpoints
• Maintenance needs identified
• Leaks
• Motors, pumps, Fans
• Filters
• Chillers, boilers, etc.
• Safety issues uncovered
• Hazardous air flow

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New Construction or RetrofitEfficiency
Opportunities

• Air Change Rate Reduction
• Temperature Set Point
• Chilled Water System Pumping
• Better Use of Cooling Towers
• Chilled Water Temperature

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More Efficiency Opportunities

• Control Problems
• Filter Coverage and Type of Filter
• Removal of Pre-filters
• Humidification
• Minimize reheat
• Lighting controls
• Pressurization losses
• Exhaust Reduction

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Efficiency Considerations during Programming

• LBNL Cleanroom Programming Guide Provides a Way
  for Owners and Designers to Explore Efficient
  Options During the Early Stages of a Project.
• http//ateam.lbl.gov/cleanroom/guide/
• ProgrammingGuide-LBNL49223.pdf

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Benchmarking Can Be Used to Establish Efficiency
Goals

• Energy Budget
• Total facility
• End use
• Integrate Efficiency Targets as Design
  Requirements for Key Systems and Components
• Cfm/KW
• KW/ton
• System resistance i.e. Pressure drop
• Face velocities

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Benchmarking highlights some important issues

• Designing and operating at higher cleanliness
  than is needed does not improve yield, but it
  does use more energy
• Air change rates can be reduced in many cases
• Chilled water pumping may be excessive
• Flow resistance has a big effect
• on life cycle cost
• Overcooling and reheating
• often represents opportunity

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My Recommendation

• Designers (and constructors) will provide
  what their customers ask for.
• If you are an owner and want efficient systems,
  ask for them.
• If you are a designer, show owners the benefits
  of an efficient design often lower first cost
  or early payback. Huge benefits over the life
  cycle.