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Close to 50% of Bentley's carbon footprint results from the electricity that we use in campus buildings. With this in mind The Office of Sustainability and Facilities Management have embarked on an agressive energy efficiency campaign.
Annual electricity consumption has decreased by over 3.11 million kilowatt-hours or 11.4% since the 2008 fiscal year (FY2008). This reduction is the equivalent of a 105 day blackout campus wide. Cumulative savings since FY2008 total nearly 7 million kilowatt-hours, which has saved the University $626,000. The total of savings attributed to electricity consumption and demand totals $1,025,160.
In 2008 Bentley completed the installation of electrical sub-meters in each building on campus and tied them into PowerLogic, an energy- and power-management application that automatically logs and displays real-time utility consumption. As a result, the Facilities Management team is able to determine how much electricity is being used in each building on campus.
Along with providing data on energy use within each campus building, sub-metering is expected to assist with establishing a predictive maintenance program, which will lower building operating expenses. All buildings with WebCTRL have been integrated with the meters to enable electrical load shedding, which relaxes a building’s set points during peak loads. Water and natural gas sub-meters will be installed in the future.
Facilities Management has historically upgraded lighting in one to two buildings per year, including the installation of occupancy sensors and energy-efficient ballasts and lamps. 99% of Bentley's buildings are equipped with high-efficiency lighting systems using:
- High efficiency T-8 lamps *
- High efficiency T-5 lamps
- Compact fluorescent lamps (CFLs)
Energy Management System (EMS) Upgrades
Bentley currently utilizes three networked building energy management systems (EMS) via a central desktop station in Facilities Management. These systems include WebCTRL, Carrier Comfort Network and Metasys. Facilities Managers are able to access these systems to troubleshoot equipment failures and temperature issues, manage building schedules and adjust temperature set-points.
Through the EMS, Bentley's Energy Systems Engineer is able to set a building's schedule (similar to a programmable thermostat in your home) so that it is heated and cooled adequately when occupied and so that energy is not wasted heating and cooling areas when unoccupied. For example: the system can be set to automatically relax cooling and heating overnight in administrative buildings when employees are not in their offices and can turn up heating or cooling at 6:00am to ensure that temperatures are appropriate by the time employees show up for work in the morning.
Over the past few years, Bentley has been systematically upgrading EMS controls in order to efficiently oversee the indoor environment and energy consumption throughout campus. Pneumatic systems are nearing the end of their useful life and are being replaced with direct digital controls (DDC), which use low-voltage wiring to control heating, cooling and lighting systems. The use of advanced building controls systems allows for more efficient scheduling and programming, as well as the use of predictive maintenance.
The construction of a 3,000 square foot solar thermal wall on the southern external wall of the Dana Athletic Center was completed in September 2009. The solar wall is made of perforated wall material and is installed several inches from the exterior wall of the building to create an air cavity.
The solar wall, which traps heat from the sun, is hooked up to a heating, ventilation and air conditioning (HVAC) unit. When the HVAC unit calls for outdoor air, the air is pulled through the solar wall and is heated in the process. The hot air rises up the air cavity created between the solar wall and the building's exterior wall and enters the HVAC unit. By providing the unit with pre-heated air, less energy is required to warm the air to room temperature. This project is estimated to save 116,000 kWh of energy per year.
* “T-8” and “T-5” refer to lamp sizes. These lights are both high efficiency and are used interchangeably on Bentley’s campus based on the size of lamp needed.
** "MTCO2e" stands for "metric tonnes of carbon dioxide equivalent." A measurement of greenhouse gases.