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Following the California energy crunch, cleanroom operators are rallying to tame the HVAC beast. It's time to join the fight
BY CHRIS ANDERSON
The California energy shortage of a few years ago opened the eyes of many in the business of running cleanrooms. Today, a small but growing cadre of cleanroom managers, as well as an application research team from the Lawrence Berkeley Laboratory, is working on ways to increase energy efficiency within cleanrooms that specifically targets HVAC systems.
While lesser energy consumption can result in savings to a company, some of the drivers of this effort have nothing to do with money.
“If you don't pay attention to conserving energy, your penalty could be perhaps consuming twice as much energy of what a very efficient system would,” says Ernie French, senior sales engineer with Norman S. Wright Mechanical Equipment, a San Francisco-based supplier of mechanical equipment systems to the cleanroom industry.
“So, it's not a real penalty to the manufacturer in terms of adding a huge amount to the cost of the product,” continues French. “But we are getting to the point where every penny counts, and you can tell a good story to the public about what you are doing.”
The bottom line, according to French: “There are other benefits to saving energy besides the costs of the energy itself.”
That said, being a good corporate citizen only goes so far. There's evidence that, for some forward-looking companies, the need to become energy efficient now and to perpetuate that in the future is more visceral.
“Since the energy crisis has passed, to some extent, we still want to be a good corporate neighbor,” says Gary Shamshoian, senior mechanical engineer with Genentech a bio-pharmaceutical company in South San Francisco, Calif. “But there's also a general concern of what the future may bring, which was accentuated during the energy crisis here in California in 2000 and a reliability concern that comes out of that.”
Unfortunately, companies aggressively pursuing improved HVAC and air-handling efficiency are still few, and those willing to share their information and data to help build accepted best practices are even rarer.
The trick to collecting data
Today, the hub of information for running energy-efficient cleanrooms is California's Lawrence Berkeley Laboratory. Bill Tschudi, project manager of the Environmental Energy Technology Division, has worked on the issue for nearly four years, beginning with case studies and benchmarking funded by local utility Pacific Gas and Electric (PG&E).
“In 1999 and 2000, we were able to dig up some data from real cleanrooms, and we did a cleanroom programming guide to give owners and designers some information on decisions they could make early in a project that wouldn't lock them into bad energy decisions,” says Tschudi.
He admits, however, that the early work only scratched the surface and that the largest obstacle is persuading operators to share data about their specific operations. “It's certainly easier today to get companies to share their data than it was five years ago, before the energy crisis,” Tschudi says. “But now, the big stumbling block is that a lot of companies don't want to have the results public for competitive reasons.”
To leap this hurdle, Lawrence Berkeley has worked out an anonymous reporting method for companies to share their data. Further, researchers from the lab have been able to assure companies that they won't be collecting information on the process of individual manufacturers, but working merely on the amount of energy used. “CFM per KW is the metric we are using, so it is merely a measure of how much air you are using per watt of energy,” Tschudi says.
This subtle shift in strategy has brought wider participation, but researchers still need more data to validate their work. If more companies step forward to share their energy consumption data, Lawrence Berkeley plans to release a benchmarking document to the industry later this year or in early 2005.
Tschudi and research partner Dale Sartor, along with PG&E and other team members, will also present their current findings at a seminar entitled “Moving Towards Energy Efficient Cleanrooms & Standards” next month at CleanRooms East 2004, in Orlando, Fla.
Against the grain?
Innovations to help squeeze energy savings out of cleanroom operations take many forms; from simply seeking HEPA filters with lower pressure drop and choosing air-handling equipment that is more efficient and sized to the specific job, to adjusting how air is moved in and out of the cleanroom and at what volumes.
Some of the results may go against the grain of how some people have operated their cleanrooms for years. “The initial reaction of what to do when a room isn't as clean as it should be is to go for more velocity,” says Shamshoian.
This increase in velocity ups a company's energy consumption—and it may all be for naught. “We're coming to the realization that we are possibly sacrificing HEPA efficiency because they weren't designed to have that much air moved through them,” Shamshoian adds. “So, part of the effort to do more intelligent design is to realize that more air is not always better. In fact, more can be worse at some point.”
Tschudi says this jibes with information he has collected. “There is no data that says more is better,” he says. “We went back and researched how the industry accepted 90 feet per minute and found it was some random decision made by some guy sitting around at Sandia.”
The push to more efficient operations has engineers working to establish, with a scientific basis, the balance between moving enough air to maintain prescribed contamination controls while reaching peak energy savings.
But getting more cleanroom managers to take a hard look at their air flow is difficult, because of what Tschudi calls “process phobia”—the fear of changing an accepted process, no matter the energy consumption, because the cleanroom is producing the expected result.
Further, companies are all over the map when it comes to which cleanroom classification they are operating, often choosing more clean over less clean (hence, higher energy consumption) without any scientific basis.
“We have often asked the naïve question of why company A picked Class 100 [ISO Class 5] for a particular room, and there was never a good answer for why it was needed for that particular process,” Tschudi says. “Then we'd go to another company performing the same process and the same operations in a Class 1000 [ISO Class 6] cleanroom and it's working just fine.”
But beyond the big leap of changing air flow, which opens up questions of proper percentages of make-up air, recirculated air and the like, managers can make very basic changes to incrementally reduce HVAC energy consumption.
First on the list is to simply look for different HEPA filters.
“Generally, putting more HEPA media in the filter is going to lower pressure drop, so that alone requires less energy,” says French. “There are different filter products and there are manufacturers that will vary the density of the HEPA media. And there are others that have developed a different kind of media.”
In many cases, the only change required here is to slide out the old filters and slip in the new. An added bonus of using denser HEPA filters is fewer change outs because the filter can take a larger load.
At Bayer HealthCare in Berkeley, Calif., principal project engineer Dennis Leung has gone one step farther in an effort to reduce the amount of air leakage around the filter. While he estimated the leakage amounted to between one to two percent of the air moving through the system, it was energy wasted—and also contributed to contamination buildup downstream in the company's duct work.
To tackle this, Leung found a local supplier, Total Filtration Systems (TFS), to solve the problem. “We wanted to look for opportunities to reduce the bypass leakage around the filters,” Leung notes. “One idea was to look at other filter frames and we discovered TFS, which has a filter frame with an interlocking gasket, and there is virtually no leakage around the frame.”
Efficient fans emerge
Another easy fix for cleanroom engineers is to use energy-efficient fans and air-handling equipment. Sounds like a no-brainer, but figuring out which fan is most efficient for a need can be a real chore.
Choosing a fan that is more efficient should be as easy as picking which one uses the least energy when moving the same unit of air against the same static pressure. The problem is, manufacturers perform their own efficiency tests using a wide range of test conditions.
“Many companies are using fan filter units, and it turns out they are not very efficient as in a big open space above the cleanroom plenum system with big fans feeding it,” says Tschudi. “In general, the fan filter units were way down in the efficiency; and one of the things we want to see in this next go 'round is whether any of them are getting close to the efficiencies of the large system.”
Something that would help cleanroom managers make better decisions about FFUs would be efficiency numbers that can be compared easily. For that reason, the IEST is forming a working group whose task will be to create testing standards for these units.
“Some of the data out there is extremely hard to justify and it is hard to duplicate,” says Monroe Britt, manager of research and technology for Clarcor Air Filtration Products, who will chair the working group. “So, the idea was to have a common test standard that everyone could reference and compare the claims of each of the fan filter unit manufacturers.”
The informal effort started a couple of years ago with the recognition that an apples to apples comparison of FFUs was needed by cleanroom managers to let them make more informed product decisions.
The next meeting of the group is scheduled to take place in late April in Las Vegas at ESTECH. Britt hopes to create a committee that includes participants from end users and cleanroom engineers to product manufacturers and consultants.
The group hopes to iron out standard test conditions that include air flow (in CFM), energy consumption, noise, air flow uniformity and vibration. Realistically, the standard may take two years to complete, though Britt hopes to draw a cross-section of the industry to aid in creating a meaningful standard.
Tschudi, a member of the IEST working group, sees the standard as one more player that can widen the amount of solid, tested, verified information about creating energy efficiency in cleanroom HVAC systems.
Meanwhile, he and the other researchers at Lawrence Berkeley continue the search for more companies willing to share data about their cleanroom energy consumption and to share what Lawrence Berkeley learns with other interested parties.
“To our knowledge, there is no other data like this available, either on an industry basis or a national basis,” says Tschudi. “When people see the range of results we have, they begin to wonder where they fit in. This is how we get their interest—to have us come through their operation and do the benchmarking.”
It's the kind of win-win situation Tschudi hopes more and more companies will take advantage of in the coming years.
If you or your company would like to contact Bill Tschudi to add data to LBL's benchmarking project, contact him at: [email protected].
CHRIS ANDERSON is a special correspondent to CleanRooms magazine based in Portland, Maine. Anderson can be contacted at: [email protected]