Campus Wide Metering System
In an effort to more efficiently manage energy usage, The College and Clean Power Markets (CPM) (formally Enerwise) designed and built a system to electronically monitor campus-wide electric usage, which would control demand and consumption from a central point of command. The system consists of a state-of-the-art integrated information platform and metering technology to collect and analyze facility information, including total energy consumption. This capability enables staff to diagnose, recommend, and implement timely solutions that help reduce costs, increase system reliability, and improve facility environment.
The goals of the campus electric metering and load management system included integration with the CPM system, feeder analysis, automatic electric demand management, data collection, logging and custom reports, and historical load profile archives.
By installing energy monitors in each building, actual electric peak demand and energy usage data is available for each separate building, which helps managers identify which feeders are operating at capacity and which have significant excess capacity. Not only does this data show where current usage is being distributed across the six campus feeders, it also aids in planning for future system upgrades, such as an electric service upgrade to 26 kV, which was completed, summer 2005. Monitoring the current system helps plan for new growth in a value-engineered way. Additionally, knowing which feeders still have excess capacity enables the technical staff to determine which can accept load from new buildings.
Automatic Electric Demand Management
Meters in each building continuously collect electric demand and usage data, which is then fed to the central server located in the energy management central office. This software is then interfaced with the existing building management control system, which allows continuous automated electric demand management, or load shedding, through the utilization of 12 established load groups of 150-200 kW each. By cycling common area building lighting and HVAC systems in a prescribed manner over these groups, the system maintains comfort, complies with New Jersey and ASHRAE codes, and saves costs in peak situations where they would previously have been hit with a demand charge. Typically, a 500-900 kW reduction is achieved during peak periods when the cogeneration plant output cannot meet campus demand.
Customized reports identify the following key data: total KWH consumption per building; total KWH per square foot per building; time and date of peak kW usage per building; total consumption cost per building; and, KWH consumption and peak data by electric feeder. Having this data on a per-building or per-feeder basis allows staff to identify the energy intensive buildings and develop targeted, building-specific energy conservation plans.
Historical Load Profile Archives
Monitored data from each building is stored in an archive where it can be accessed later to analyze system problems. Electricity problems on a per-feeder or per-building basis can be studied in comparison to past reports. Prior to the installation of the system, The College already had some device controls in place. The College wanted to additionally create more efficiencies with a comprehensive energy management plan, complete with a strategy for automatic load shedding at times of peak demand. In short, The College recognized that those efficiencies cannot be gained until the all of the data is harnessed and turned into information, which is one of the most important and effective tools for decision making.
By utilizing centralized device controls already in place, the new hardware and software for the advanced metering technology integrated the existing building automation system. This proved essential to creatively utilizing systems already in place, thereby preserving the initial investment. The project not only required integrating the new monitoring system with the existing building controls system, but also required creative strategies for sending the information across the campus. While The College has a campus Intranet that could provide a communication vehicle for the energy information, College management decided not to use this approach. Instead, a range of potential solutions, including satellite, wireless, cable, or even radio frequencies to transfer information were considered. Ultimately, it was determined that the energy data could be transmitted along unused channels in existing standard copper telephone wires, thereby utilizing infrastructure already in place and keeping both the management system and energy settings securely within the jurisdiction of authorized staff.
The system is just the first phase of a Central Utilities Management Program. Although The College currently only monitors electricity, plans are underway to expand metering to both steam and chilled water systems, so that in the future all campus utilities can be monitored. The electric metering system represents the best of what energy management systems can do creatively use communication tools and information to manage energy, save costs, and improve efficiency in a range of situations.