2012 Technology Award Case Studies 2010 a total energy use of 72% of 2008 was recorded vs. the 59% predicted by the energy cost budget. But the difference for 2010 was due to the timing of the 12-month long floor-byfloor retrofit project that began about April 2009 and was fully completed in April 2010. The energy reduction data for 2010 includes about eight out of 12 months of expected benefits. LEED commissioning was completed in March 2011 and yielded additional benefits. For example, supply duct static pressure dropped from 4 in. to 2 in. w.g. (996 Pa to 498 Pa). The system was monitored for a six-month LEED performance period from April to September 2011. Energy reduction trends predict that energy use will approach 59% of previous as predicted by the ECB. Commissioning created significant overall energy savings of 14.62% on a kBtu/ft2 basis, and an increase in the ENERGY STAR building score from 54 to 66 (extrapolated using December 2011 data). Annual utility cost savings of $54,200 yielded a simple payback of 2.2 years for the commissioning effort. Indoor air quality will be improved. CO2 sensors have been added to the return air plenums for demand control monitoring of the ventilation systems. Outdoor airflow measuring was installed to measure ventilation airflows. One hundred percent economizer cooling control is now programmed. DD-VAV mixing box cooling valves are controlled to a minimum open as required ensuring better indoor air quality. An occupied/ unoccupied control procedure has been implemented. Conclusion Several benefits were obtained by the project. Certainly significant energy savings are returned by the HVAC system revisions. Wireless thermostats blend easily with landscape furniture and avoid wiring costs. Sound masking systems installed present near optimum space noise characteristics despite reduced airflows in the HVAC system. ENERGY STAR rating is up from 28 to 66 and still rising! Simulation and actual site energy predict the revised system will attain a rating of 65 or better to enable LEED Gold certification. The total improvements befit the environmental expectations of the world headquarters campus of Deere & Company. Environmental Impact The project returns significant energy savings. Analysis predicts a 55% reduction of heating gas, a 36% reduction of electric kilowatt-hours, and a total cost reduction to 59% of previous. Greenhouse gas release will be reduced by 5,540 tons for electric reduction and 3,219 tons for natural gas reduction in carbon equivalent per year. References 1. Warden, D. 2004. “Dual fan, dual duct goes to school.” ASHRAE Journal 46(5). www.info.hotims.com/41638-47 50 ASHRAE Journal April 2012