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Cleanroom Energy Benchmarking Results - PowerPoint PPT Presentation


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Overview. 9:30-9:45 Introduction and research overview 9:45-10:30 Energy benchmarking findings Savings-by-design cleanroom efficiency baselines 10:30-10:45 Break 10:45-11:30 Group discussion of successful efficiency projects and barriers 11:30-12:00 Top ten air system opportunities

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Presentation Transcript
Overview
Overview

9:30-9:45 Introduction and research overview

9:45-10:30 Energy benchmarking findings

Savings-by-design cleanroom efficiency baselines

10:30-10:45 Break

10:45-11:30 Group discussion of successful efficiency projects and barriers

11:30-12:00 Top ten air system opportunities

12:00-1:00 Lunch

1:00-1:30 Demand controlled filtration and Standardized testing and reporting of fan-filter unit performance

1:30-2:15 Low hanging fruit – opportunities in cleanrooms

2:15-2:30 Q&A, Wrap-up, Discussion

What is the audience background?

What industries/institutions are represented?




Prior cleanroom research
Prior cleanroom research

  • Roadmap for California Energy Commission

  • Cleanroom Programming Guide

  • Benchmarking 14 cleanrooms

  • Case study reports

  • California market assessment

  • Laboratory Design Guide


Current cleanroom activities
Current cleanroom activities

  • Benchmarking and Best Practices

  • Fan-filter unit test procedure

  • Demand-controlled filtration

  • Minienvironment efficiency

Cleanroom Measured Electricity

End-use


Energy benchmarking
Energy Benchmarking

  • Improves business performance - saving energy puts $$ directly to the bottom line

  • Optimizing facility systems may improve:

    • Safety

    • Reliability

    • Production (yields) or Research results

    • Maintenance and operation

    • Energy performance

    • And may Lower capital cost

  • Some improvements are low or no cost


Benchmarking benefits
Benchmarking benefits

  • Establish baseline to track performance over time

  • Enable comparisons to others

  • Prioritize where to apply resources

  • Best practices become apparent

  • Efficiency techniques can be applied to future projects


Benchmarking additional benefits
Benchmarking- additional benefits

  • Reliability Improvement

    • Controls

    • Setpoints

  • Maintenance

    • Leaks

    • Motors, pumps, Fans

    • Filters

    • Chillers, boilers, etc.

  • Safety

    • Hazardous air flow


What are the stakes
What are the stakes?

Utility bills from one case study:

Billing daysConsumptionDollars

Elec 368 38,084,148 kWh $2,549,330

Gas371 70,203 therms $43,715

approx 20,000 sq ft cleanroom in 68,000 sq ft building w/ $.065 ave. per kW


Lbnl energy benchmarking
LBNL energy benchmarking

  • Energy end-use was determined along with energy efficiency of key systems.

  • Energy efficiency recommendations were provided to each facility. These are being used to identify “best practices”

  • Prior benchmarking results available at: http://ateam.lbl.gov/cleanroom/benchmarking/

    results.html



Energy intensive systems
Energy intensive systems

We examine energy intensive systems

Representative end-use


System efficiency vs production efficiency
System efficiency vs. production efficiency

  • Metrics allow comparison of air system efficiency regardless of process – e.g. cfm/kW or kW/cfm

  • Production metrics can mask inefficient systems – e.g. kW/cm2 (of silicon) or kW/lb of product


Cleanroom air system metrics
Cleanroom air system metrics

  • Air systems – cfm/kW

    • Recirculation

    • Make-up

    • Exhaust

  • Cleanroom air-changes – ACH/hr

    • Recirculated, filtered air

    • Outside air (make-up and exhaust)

  • Average room air velocity-

    • ft/sec


Recirculation systems

Average 3440

Average 1953

LBNL Data

Sematech Data

16


Recirculation system hypothetical operating cost comparison
Recirculation system hypothetical operating cost comparison


Make-up air systems

Average972

Average 946

LBNL Data

Sematech Data

18


Factors affecting make up system efficiency
Factors affecting make-up system efficiency

  • Resistance of make-up air path

    • Air handler/coil face velocity

    • Coil Pressure Drop

    • Duct/plenum sizing and layout

    • Adjacency of air handler(s) to cleanroom

    • Filters

  • Fans

    • Fan and motor efficiency

    • Variable Speed Fans

  • Pressurization, losses, and exhaust


Air change rates and air velocity
Air-change rates and air velocity

Not an exact science…

  • The Institute of Environmental Sciences and Technology (IEST), and others, provide recommended recirculation air-change rates

  • Many large companies set their own criteria

  • Studies have shown that more airflow is not necessarily better

  • Philosophy of ceiling filter coverage varies

  • Pressurization/losses can have a large impact

  • Air changes and cleanroom protocol are both important



Ceiling filter coverage achieving the same cleanliness level
Ceiling filter coverage – achieving the same cleanliness level



Standby generation loss

  • Several load sources

    • Heaters

    • Battery chargers

    • Transfer switches

    • Fuel management systems

  • Heaters alone

    (many operating hours)

    use more electricity than ever produced by the generator

    (few operating hours)

Opportunity may be to reduce or eliminate heating, batteries, and chargers

24


C omponent efficiencies also vary
Component efficiencies also vary

Fan-Filter Units

2800 cfm/kW

Source: Industrial Technology Research Institute, Taiwan



Case study
Case study

Good news/Bad news

Recirculation setback at night and on weekends was successfully utilized and dramatically saved energy

Unfortunately air-change rates were higher than they needed to be and the system had a high pressure drop (resistance to airflow)


Ducting to hepa filters creates large pressure drop
Ducting to HEPA filters creates large pressure drop


Case study recirculation setback
Case study – recirculation setback

  • Setback based solely on time clock,

    8:00 PM-6:00 AM

  • No reported process problems or concerns from process engineers

  • 60% – 70% power reduction on turndown


Recirculation setback energy savings
Recirculation setback – energy savings

  • Annual fan savings from daily and weekend setback:

    1,250,000 kWhapproximately $138,000

  • Cooling load reduction when setback:

    234 kW65 tons


Case study recommendation
Case study - recommendation

Air-change rates exceeded IEST recommendations during daylight operation and were well above recommended minimums during setback.

Further large reductions in energy use are possible by reducing air change rates and should not affect the process within the room.


Iso 14644 4 international standard for design and construction of cleanrooms
ISO 14644-4 (international standard for design and construction of cleanrooms)

(Its OK to save energy!)


What are we learning from cleanroom benchmarking
What are we learning from cleanroom benchmarking?

  • Systems are often oversized

  • Contamination control can be achieved with reduced air change rates

  • Cleanliness ratings are often higher than needed

  • Rule of thumb criteria should be examined

    (e.g.: 90ft/min, air changes, filter coverage etc.)

  • Overcooling and subsequent reheat can be excessive

  • Chilled water pumping is often an opportunity

  • Chilled water temperature often is lower than needed


Using benchmarks to set goals
Using benchmarks to set goals

Building owners and designers can use benchmark data to set energy efficiency goals.

  • Cfm/KW

  • KW/ton

  • System resistance – i.e. pressure drop

  • Air handler face velocities

  • Others


Recirculation system performance
Recirculation system performance

System Performance Target


Statewide savings by design baselines
Statewide Savings-By-Design baselines

Cleanroom baseline criteria

Recirculation system

  • Metric: Watts/cfm

  • Determine watts by measurement or from design BHP

    W = BHPx746

    0.91

  • Determine flow from balance report or design documents

  • Baseline value is 0.43 W/cfm (2,325 cfm/kW)

  • Annual savings=(Baseline - Efficiency metric) x Annual cfm


Savings by design baselines
Savings-By-Design baselines

Cleanroom baseline criteria

Make-up air system

  • Metric: Watts/cfm

  • Determine watts by measurement or from design BHP

    W = BHPx746

    0.91

  • Determine flow from balance report or design documents

  • Baseline value is 1.04 W/cfm (961 cfm/kW)

  • Annual savings=(Baseline - Efficiency metric) x Annual cfm

    where annual cfm = .7 x design cfm


Savings by design baselines1
Savings-By-Design baselines

Additional cleanroom baseline criteria

  • Chilled water system

  • Hot water production

  • Compressed air


Savings by design
Savings-By-Design

Five largest energy savings opportunities:

  • Low face velocity in air handlers

  • Variable speed chillers

  • Free cooling for process loads

  • Dual temperature cooling loops

  • Recirculation air setback


Best practices conclusions
Best practices/conclusions

  • Clean space should be minimized

  • Better load determination is needed - actual load (not nameplate) and efficient strategies for load growth

  • Cleanliness classification needs to match contamination control problem (cleaner is not necessarily better)

  • Air-change rates can be optimized and save energy

  • Low pressure drop systems (low flow resistance) are much more efficient

  • Optimizing exhaust is an opportunity

  • There is no silver bullet – many strategies combined will provide best performance

The answer is yes – cleanrooms can be more energy efficient!


Questions
Questions?

Thank you!

http://hightech.lbl.gov


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