Balancing Energy Conservation and Safety in a New Academic Clean Room:

Pam Greenley, MIT EHS

MIT has been and continues to be on the cutting edge of nanomaterials electronics research conducting much of that research in a 30-year old clean room facility. A 200,000 sq ft new facility is currently under design for the center of campus. Our hope is that the new facility will have the longevity of the old facility with significant improvements to researcher productivity, safety and energy efficiency. This type of facility presents a triple challenge in achieving HVAC energy conservation for the following reasons:

  1. we use some of our most hazardous materials for this type of research resulting in H occupancy classification with dictated air change rates,
  2. clean (Class 100 and 1000) conditions are achieved by moving large quantities of recirculating air through HEPA filters, and
  3. specialty hoods and enclosures are the norm as opposed to conventional laboratory chemical hoods where lower face velocities and turn downs are well established by best practice codes.

Many HVAC energy conservation strategies were studied and those that pertain most to achieving both energy conservation and enhanced safety will be focused on during the presentation. Under consideration and listed in order of degree of common to uncommon approaches for clean rooms based on the design team's research include:

  1. Exhaust Air Heat Recovery – decentralized scrubbing only for tools that need it rather than a centralized system makes this possible.
  2. Reducing air recirculation rates in the clean room when particle counts are satisfied,
  3. Pressure independent valves that allow the clean room to be operated at the exhaust load needed rather than a future full fit-out state
  4. VAV pressure independent valves that support varying hood exhaust rates based on a tool's safe mode state (tool not in use) or a clean/wet benches sash position,
  5. Moving from open clean/wet benches to more enclosed hood sash configurations to provide better splash protection and lower flows. Wet/clean benches that allow for less overall chemical use through the use of condensers for heated baths will also be discussed.

Preliminary projected energy savings over the base case will be presented where available.

Learning Objectives

  • Understand how to choose a safer and more efficient wet process station
  • Become familiar with ways to reduce HVAC energy consumption in clean rooms
  • Be able to select the right control device for unususal applications.

Biography:

Pam is a Certified Industrial Hygienist with a Masters Degree in Chemical Engineering. She has worked on MIT's lab design projects for over 20 years. She has been an associate director at MIT for 4 years. She teaches laboratory HVAC basics and a lab energy conservation course at Eagleson Institue. Most recenlty, she helped found the New England chapter of I2SL.

 

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