The campus is estimated to have between 1,700 and 1,800 fume hoods in operation at the present time. The majority of these are constant air volume (CAV) hoods without heat recovery that operate continuously. Several hundred variable air volume (VAV) hoods also exist, which are in operation only when the hood sash is raised. These hoods, however, are often operated continuously. Based on a Trane TRACE energy model for a typical fume hood on campus, the cost of conditioning air to replace the air vented by a CAV fume hood over the course of a year is estimated to be approximately $5,500 per year. The energy model also predicts an energy usage for VAV hoods, CAV hoods using heat recovery, and VAV hoods using heat recovery to cost about $2,100, $3,200, and $1,500, respectively. Fewer than 200 of the campus’ 1,700 fume hoods are VAV. These figures provide an opportunity to significantly reduce fume hood energy consumption. If the campus takes into account some portion of fume hoods that utilize VAV or heat recovery, the University can conservatively assume the average cost of hood operation to be $3,750 per year. Using this average cost, the total energy cost that can be attributed to campus fume hoods is roughly 9 percent of the campus total. The University believes the physical number of fume hoods in operation can be reduced by 20 percent to 25 percent. This is based on the fact that many rooms have multiple hoods that do not require simultaneous use, and that many of these fume hoods are currently used for chemical storage and cannot be removed. The remaining fume hoods should all be converted to VAV systems with heat recovery—these can reduce a CAV hood's energy consumption by 70 percent. This strategy will also require an educational component. Groups and individuals will need to be educated on operating hoods correctly and to shut the hood sashes when not in use. The above actions can reduce campus energy consumption by at least 2 percent. Our new target for fume hoods is 2 percent.
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Although the SAIC report describes the potential energy savings from behavioral changes in its section on metering, it does not include it in its analysis. The University believes a well designed incentive and education program can reduce campus energy consumption by at least 5 percent. Such a program should seek to ensure that cost savings from energy conservation measures benefit building users (e.g. “energy rebates” to students in high-performing departments, or energy-driven reductions in overhead rates for faculty). In addition, adding real-time energy displays in campus buildings and via electronic media can help promote awareness and incentive for improvement. Many buildings have limited or no control over their thermostat settings. However, the departments that occupy these spaces do get a substantial influence in setting building temperatures and enacting more reasonable settings. This will require behavioral change from the academic units and the building occupants. The target for behavioral changes is 5 percent.
The SAIC report assumes very little potential for savings from the purchase of ENERGY STAR® equipment such as computers and printers. Thin client computers being deployed on campus today offer the potential for a 90 percent reduction in energy use compared to desktop computers. A broad deployment of low-energy computing equipment, server virtualization, consolidation of IT facilities (web servers, file servers, terminal servers) and reduction in the total number of server instances can all yield significant savings on both costs, equipment purchase expenses, and campus IT costs. Use of standards more aggressive than ENERGY STAR® for all equipment purchases (i.e. washers and dryers in residence halls, etc.) can yield substantial savings. Students are becoming increasingly independent of campus computer labs, preferring to remotely access campus computing resources as needed. Campus’ decentralized IT status results in a disparity of these and other practices. For example, many IT groups discourage users to enact computer power management settings or turn off their computers in the evening and the weekends to allow for security upgrades. However, technologies such as Wake or LAN can allow computers to be powered down and reactivated for upgrades. The target for IT and other electrical equipment is 1 percent.
This category includes conversion from constant air volume reheat to variable air volume, eliminating summer steam usage (reheat), heat recovery, variable speed drives for fans and pumps, and steam system maintenance (including trap replacement and pipe insulation). The target for other HVAC is 12.5 percent.
This category includes using instantaneous and semi-instantaneous hot water heaters, increasing insulation on hot water tanks, utilizing recovered heat from chiller condensers and other sources, and temperature setbacks. The target for hot water is 4.5 percent.
The SAIC report derives most of its envelope-related savings from window replacement and roof insulation, assuming that only 1 percent of campus energy can be saved by weatherization. The report did not consider changes such as entry-way retrofits to reduce heat loss during entry and exit or improvements in insulation in areas besides roofs. Additionally, the report made no estimation of chilled water savings due to either weatherization or wall insulation, or any potential savings from decreasing heat gain through roofs due to improved reflectivity or vegetative roofs. Improvements to building envelope, weatherization, improving insulation levels in roofs and other areas, and tightening building infiltration and exfiltration would offer a 4 percent reduction in campus energy use, though more is highly likely. The campus target for envelopes is 1 percent.
Commissioning for existing buildings (sometimes referred to as retro-commissioning or RCx) is a systematic process for investigating, analyzing, and optimizing the performance of building systems by improving their operation and maintenance to ensure their continued performance over time. This process helps make the building systems perform interactively to meet current facility requirements. The campus RCx teams have found a 29 percent average reduction in energy use and emissions for the 14 existing buildings (2,347,170 sq. ft.) they have examined. This success rate shows that there is enormous potential for this reduction strategy. Campus RCx activities have included: repairing and recalibrating sensors, valves and dampers, upgrading control systems, demand control ventilation, and implementing scheduling for air handling units, among others. The current RCx program is being augmented by several Energy Service Company (ESCO) contractors. A plan to revisit every building on a 5- to 8-year basis should also be instituted in order to maintain these savings. A direct-digital control command center to monitor temperature control and alarms to determine when systems fail or inappropriate temperature settings are being utilized will be constructed by the end of calendar year 2012. Based on the campus RCx program performance to date, savings proposed by SAIC for this section can be increased. The new target for RCx is 12 percent.
The campus is in the process of retrofitting older T12 fluorescent lighting fixtures by replacing them with more energy-efficient T8 (or T5)fixtures and electronic ballasts. The lighting retrofit proposed in the SAIC report would reduce campus energy consumption by ~1.6 percent; a very small amount of this is due to the use of occupancy sensors and day lighting controls. Extending this retrofit to smaller campus buildings, replacing other lighting fixtures (besides T-12s), and a wide deployment of both occupancy and daylight sensors (which can reduce lighting use by 20 percent to 80 percent depending on location) should be able to provide significantly more energy savings than predicted in the SAIC report. The campus target for lighting is 2 percent.