High Performing Buildings - Summer 2011 - (Page 16)

Courtesy: Tim griffith Above Meeting rooms are strategically located between the façade and atria to reduce the use of electric lighting during the day. White walls help reflect light, enhancing daylighting. Right Chilled beams heat and cool common spaces and other non-lab areas of the building. This system, which uses pumps and pipes, conditions the building more efficiently than an air-distribution system using fans and ductwork. first year verifies that Y2E2 consumes 50% less energy than similar laboratory buildings in Stanford and thus sets an improved benchmark for future campus buildings. Y2E2’s energy savings equate to an annual CO2 emissions reduction of 223 metric tons (at 0.524 lb CO2 per kWh based on Pacific Gas & Electric data). Y2E2’s source of power is the campus cogeneration facility that is running 100% on natural gas (at 53.06 kg of CO2 per MBtu of natural gas). Annual heating savings (8,761 MBtu) and chilled water savings (2,986 MBtu) result in a reduction of an additional 618 metric tons of emissions. This brings the total emissions reduction to about 841 metric tons. Lessons Learned significant lessons were learned from the post one-year occupant and facilities survey and re-calibration of energy model. subsequent buildings at stanford, including the Huang engineering Center (130,000 gross square feet), nanocenter (105,000 gross square feet), and leed Platinum seeking Knight graduate school of Business (600,000 gross square feet) learned from Y2e2 and have incorporated many of the lessons here. Mixed Mode Feedback to occupants Bms feedback systems that informed building occupants via a read-only dedicated Bms web page had mixed success. The building accommodates four atria and each atrium is connected to naturally ventilated rooms. A message such as “Atria A & B: occupants should close windows” would flash on the Bms web page to inform the occupants in that zone. it was easy for the occupants to ignore these messages or not access the web page regularly. subsequent design solutions at the stanford Huang engineering Center and Knight graduate school of Business incorporated window contact strips to better manage mixed mode operation. in these buildings, contact strips at each operable window are connected to the zone HVAC system (chilled beam, VAV terminal). The zone level system will shut off when the occupant opens the window. Calibrated energy Modeling A calibrated energy model was needed to effectively incorporate measurement and verification activities into the post-occupancy performance vetting. Without it, the building appeared to be significantly less efficient simply because it was being used more (and longer) than originally modeled. server room economizer Air: fan coil units (fCu) serving the iT/electrical rooms were found to maintain a base load of 30 tons through the year. This load could be lowered significantly by introducing outdoor air (oA) economizers to these units. aCB Variable air Volume operation The VAV operation of the active chilled beams was identified as an additional energy-saving measure. The building design did not incorporate VAV for several reasons. The air volume needed to condition the space is reduced with the use of chilled beams even in a constant volume system. VAV operation optimizes performance beyond that. Improvement in submetering accuracy submeter monitoring of end uses such as lighting, HVAC components, plug loads, etc., should be calibrated and, where necessary, replaced (under warranty). such detailed information was critical to understanding performance and allowed for targeted investment of operational time and resources. While submetered data for Y2e2 is not publicly displayed either via light boards or intranet, subsequent buildings have incorporated these systems, generating awareness and allowing building users to take part in the optimization process. 16 HigH Performing Buildings summer 2011

Table of Contents for the Digital Edition of High Performing Buildings - Summer 2011

Commentary
Contents
Stanford University's Y2E2
The Christman Building
The Gettysburg National Military Park Museum and Visitor Center
Cannon Design Regional Offices, Power House
Great River Energy Headquarters
Letters
Products
Advertisers Index

High Performing Buildings - Summer 2011