California State University–Chico, located about 90 miles north of Sacramento, has taken giant steps to become more sustainable in recent years, reaping accolades that reflect a campus-wide environmental mission. The institution has reduced its carbon footprint by 36 percent since 2008, was one of the first universities to sign on to President Obama’s Climate Change Challenge, and was a finalist for the Planet Forward College and University Climate Leadership award. According to university president Dr. Paul J. Zingg, sustainability “is a fundamental value of this institution.”
One particular honor that Chico State earned in 2011—the University of California and California State University’s Comprehensive Energy Management Program sustainability award—represents the school’s commitment to its built environment. Chico State is a leading practitioner of monitoring-based commissioning (MBCx), the application of building management systems to measure energy usage trends, identify ways to boost efficiency on building systems, and make adjustments to those systems to optimize efficiency. MBCx has been performed on six campus buildings to date, including the Student Services Center.
Some campus buildings have undergone what Neil Nunn, the campus’s chief engineer, calls a “light version” that doesn’t include extensive system revamping. (A light MBCx program identifies a range of energy efficiency measures, implements some low-cost measures, and suggests more costly steps to be taken later when funds become available for implementation.)
Other campus buildings have had the full MBCx treatment. The Student Services Center had a full-scale MBCx in 2010 with consultant EnerNOC guiding the process, and is the best exemplar of MBCx’s value. Retooling the HVAC system reduced energy needed for heating the 71,950-square-foot structure by 65 percent, for cooling by 30 percent, and for electricity (excluding cooling) by 37 percent. The resulting total annual cost savings is estimated at $66,000.
An upgrade of the building’s energy management system, a prerequisite to the effort, enabled the capture of energy-trending data that could be analyzed graphically. That work led to several major efficiency improvements, including the reprogramming of the air-handling-unit control sequences (so that heating and cooling units operate separately) and the reprogramming of the variable air volume terminals (so that heating now uses mostly return air).
The commissioning also corrected the problem of return air escaping through the outdoor air damper of one of the air-handling units, which made the system work excessively. Changing fan speeds on 475 air handlers from static pressure control to volume demand control cut the energy needed to run the fans by half, which resulted in the lowest energy cost per square foot on campus.
The adjustments yielded a target thermal window that ranges from 68 degrees to 78 degrees. As a result, occupants can experience a 10-degree swing in a single day. That’s more variability in thermal conditions than they were accustomed to, so it took time for them to become acclimated. “It took a lot of tweaking to keep most occupants happy,” Nunn says, admittedly.
Optimizing HVAC systems didn’t end with the conclusion of the MBCx project. Real-time monitoring enables operations staff to quickly identify malfunctioning fans and other system components and immediately dispatch maintenance staff when something needs attention. Indeed, to get the most value out of the process, each building system has to be constantly monitored and adjusted to keep performance at top efficiency.
Chico State is committed to applying MBCx to most of its
major buildings, though it will take years before this is done campus-wide due to funding constraints. Funding comes from the statewide university chancellor’s office in partnership with four California utilities, which provide rebates for efficiency improvements. Though the up-front investment for MBCx is substantial—about $95,000 for the Student Services Center—the value is compelling, particularly when it contributes to a core institutional value.
Zingg says the cost savings resulting from energy efficiency is important but that it is a green mindset that drives the effort towards continuous energy-efficiency improvement: “We want to provide a good example for sustainability that students and others will embrace.”