INNOVATIONS
Volume 3, 2003

www.thermaltech.com

We're Building System Performance™ ·  TE High-Performance Buildings™ 
TE Engineer-Led Turnkey™

   TOP 10 INNOVATIVE ENGINEERING APPROACHES

We're counting down our Top 10 list in INNOVATIONS

#10 - Life-Cycle-Cost Based Decision-Making - October/November 2002

#9 - DOAS (Dedicated Outdoor Air Systems) - December/January 2003

#8 - Radiant Cooling - February/March 2003

#7 - DALI Lighting Control Systems - April/May/June/July 2003

#6 - All-Variable-Speed (AVS) Chilled Water Plant

Aren't variable-speed chillers expensive?  Not any more.  All of the major manufacturers routinely provide 480-volt variable-frequency drives (VFDs) on chillers as large as 1,200-1,500 tons.  Most VFDs are so compact they are mounted right on the chiller.  Even so, you can forget about the cost premium.  Less-efficient variable-speed chillers can have a lower operating cost than high-efficiency chillers of equal cost.  That is, you are better off putting your money in the VFD than the tubes.

In old-style plants, with constant-speed condenser water pumps, it is more efficient to load a chiller to the maximum before starting another chiller and its related condenser-water pump.  The AVS plant operating strategy is different.  Chillers are staged to keep them operating near their "sweet spot." Since the condenser water pumps are variable speed, there is no jump in pump power when another chiller is started.

How are all of the variable-speed components controlled?  A simple open-loop strategy is used.  Cooling-tower fan speed is determined from variables like percent of plant full capacity rather than trying to maintain certain water  temperatures.  For example, if the plant is at 50% of design capacity, all cooling tower fans may be operated at 80% speed.  A table-lookup scheme is developed once the equipment has been selected.   This method of control is very stable, since adjustments need only be made every few minutes, using variables that do not change rapidly.  

Multiple condenser-water and chilled-water pumps may be operated at a slow speed rather than one pump at full speed.  The pumps are staged based on wire-to-water efficiency rather than waiting until a pump reaches full speed.

What's the bottom line?  Seasonal performance can be improved by 20-40% compared to conventional plants with only a minor investment in engineering design and licensing fees.  

The AVS plant control algorithm is a patented process ThermalTech engineers can implement for you under an economical licensing agreement with the developer.

Thomson Learning is one of the world's leading providers of integrated information solutions for individuals, businesses, and institutions.  Their brands include Westlaw legal references, Chilton auto repair manuals, and hundreds of textbooks and educational materials.  

ThermalTech recently helped Thomson expand their computer center in Mason, Ohio.  The ThermalTech team faced an aggressive schedule and a continuously-active facility.

Scope of Work:

• Double the size of the data center (3,200 SF to 6,800 SF)
• Include flexibility for future expansion
• Keep existing data center operational during construction
• Complete design and construction in 10 weeks

Systems Added:

• 400 kVA static uninterruptible power supply (UPS) system
• Infrastructure for 600 kW emergency generator, using owner's 400kW generator
• Power distribution units (PDUs)
• 120 tons of computer room air conditioners, pumping, drycoolers
• Preaction sprinkler system
• PLC control system

Success Factors:

• Met agressive time schedule
• Re-used a generator from another Thomson facility - saved time and money
• Designed around cooling equipment and pumps that were available off-the-shelf
• Custom electrical bus tap on main building riser to feed new loads
• Turnkey control system provided by ThermalTech (all programming, control panels, startup, testing)
• Improved ventilation, air distribution, system reliability, power quality

Ready for a fun road trip to Pittsburgh?  ThermalTech is chartering a luxury highway cruiser to take friends and allies to the 2003 US Green Building Council’s GREENBUILD International Conference and Expo, November 12-14.  This year's conference in the new Pittsburgh Convention Center (a sustainable-design building) is likely to be attended by over 3,500 green and high-performance building experts.  On board from ThermalTech will be Gary Davies, Dana Connolly, Tom Kennedy, and Rick Anderson.  

Save money on travel expenses, avoid driving and parking hassles, meet others active in the Cincinnati sustainable building industry, and have fun while you travel to and from the conference.  If you would like to join us or have any questions regarding the trip, please call or email Sara Meagher (513) 561-2271, smeagher@thermaltech.com.

What's new at ThermalTech?

ThermalTech proudly welcomes the following new professional staff:

	Julie Krommer  Julie Krommer, a recent University of Cincinnati graduate, joined our Cincinnati office as a mechanical engineer.  She acquired 2 years co-op/intern design experience with a national engineering firm while attending college.
	Rebbeca Daniel Rebbeca Daniel joined our Cincinnati office as a mechanical engineer.  She has BSME from the University of Cincinnati and 4 years experience in HVAC system design.  She spent the last year getting her MBA from the University of Cincinnati.