Presentation on theme: "CLEANROOM ENERGY BENCHMARKING William Tschudi October 9, 2002 Acknowledgements: Pacific Gas and Electric Company, Rumsey Engineers"— Presentation transcript:
CLEANROOM ENERGY BENCHMARKING William Tschudi October 9, 2002 Acknowledgements: Pacific Gas and Electric Company, Rumsey Engineers
Energy Benchmarks Goal: Identify Energy Efficiency Opportunities in Cleanrooms Through Comparison of Benchmark Data
In California many industries rely on Cleanrooms: Cleanroom Energy Benchmarking
Why Benchmark High-tech Buildings? From PG&E’s perspective: PG&E 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
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.
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
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
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
Metrics Ability to compare performance regardless of process Focus on system efficiency rather than production efficiency
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
Central Plant metrics Chiller efficiency – kW/ton Cooling tower efficiency – kW/ton Condenser water pump efficiency – kW/ton Chilled water pump efficiency – kW/ton
Vision - an Energy Benchmark Data Base Anonymous reporting Comparison of similar class systems Comparison of components Comparison of overall facility No production metrics Sufficient data to identify best practices
Cleanroom Benchmarking Some Results and observations to date
Energy End Use
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
Energy Intensive systems Recirculation of air in cleanrooms
Recirculation Air Comparison
Recirculation Systems Design vs. Measured
Why are Design Efficiencies less than Measured Efficiencies? Design efficiency is generally understated because larger power consumption (kW) is generally assumed. (nameplate vs. actual)
Benchmarks as Design Criteria Idea! As a building owner, Why not specify a system efficiency?
Recirculation Air Comparison System Performance Target
What is the cost impact?
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
Make-up Air Comparison
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
Make-up Air Design vs. Measured
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
Air-Change Rate Comparison
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
Chilled Water Systems Comparison
Chilled Water System Observations 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 Wide variation in overall efficiency
Chilled Water System Resources Existing efficiency information for chilled water plants is under-utilized.
Chilled Water System PG&E’s CoolTools
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
New Construction or Retrofit Efficiency Opportunities Air Change Rate Reduction Temperature Set Point Chilled Water System Pumping Better Use of Cooling Towers Chilled Water Temperature
More Efficiency Opportunities Control Problems Filter Coverage and Type of Filter Removal of Pre-filters Humidification Minimize reheat Lighting controls Pressurization losses Exhaust Reduction
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. ProgrammingGuide-LBNL49223.pdf
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
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
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.