Ravenscroft School

Ravenscroft School-Raleigh, NC

emon submeters at bill gates home

Submeters Measure Energy Savings, Help Drive Campus-Wide Building System Upgrades

As a learning tool, Ravenscroft's enterprise-wide meter dashboard provides visibility on campus energy initiatives, including carbon footprint of metered buildings, consumption (kWh), demand (kW) and other conservation-related parameters.

Figure 1. Ravenscroft School needed an effective, economical way to monitor and evaluate energy and natural gas usage in it's largest buildings. E-Mon D-Mon submeters were selected for their ability to tie into the building management system for a centralized way to monitor the school's energy profile. In the process, facility managers learned more about how, when and where the energy was being used — justifying new building system upgrades.

Ravenscroft School

Founded in 1862, Ravenscroft School serves some 1,235 students in lower (pre-K), middle (6-8) and upper school (9-12) divisions on a beautiful 125-acre wooded campus in Raleigh, North Carolina. As a non-profit co-educational college preparatory day school with more than 200 full-time employees, Ravenscroft appears to be well on its way to realizing its stated goal of becoming the area's leading independent academic institution and one of the top of its kind in the Southeast.

In addition to academic excellence, as evidenced by the Class of 2011's four National Merit Finalists, two National AP Scholars and significant AP class participation: Ravenscroft also emphasizes a strong sense of community involvement and environmental stewardship. To that end, a number of campus-wide sustainability initiatives are already producing successful outcomes, thanks in large measure to the high level of participation by the school's faculty, staff and student communities.

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Ravenscroft Goes Green

Under the leadership of Doreen C. Kelly, Ravenscroft's Head of School, visions of weaving sustainability into the fabric of the school's culture is playing out on campus in a number of ways. In addition to recently implementing composting in the dining hall, the school is further reducing its carbon footprint through more aggressive recycling, dual-flush toilets, light/motion sensors and other energy conservation measures.

Figure 2. Chris Farrow, Director of Buildings and Grounds, reviews meter data used to baseline seasonal energy usage. The kWh/kW data helps the facilities staff optimize building system performance to reduce energy use and to cut cost without sacrificing the comfort and quality of the classroom environment. The data also helps managers justify and prioritize building system upgrades and retrofits.

In 2008, Ravenscroft joined the Green Schools Alliance and now competes against other area schools in the GSA's annual Green Cup Challenge. On the heels of admirable showings in previous contests, in 2011 Ravenscroft tied for first place among Carolina schools by reducing its electrical consumption by more than 10 percent, thus preventing almost three-and-a-half tons of C)2 from being injected into the atmosphere.

As the primary energy data acquisition tool, electric submeters not only played a key roll in measuring and verifying building performance for the Green Cup Challenge, but also provided accurate energy consumption and demand profiles for all metered buildings on a 24/7 basis. With the exception of Murphy Hall chiller plant, in which only an electric meter was installed, seven other campus locations totaling more than 259,000 square feet were metered to track both gas and electricity (Figure 2.)

How submeters facilitate the "greening" process

In response to challenging "green" applications like Ravenscroft School, E-Mon and others have developed advanced hardware and software tools that specifically address the measurement and verification (M & V) needs of the sustainable facility market. Certified to ANSI C12.20 national accuracy standards, E-Mon D-Mon smart meters offer a number of advanced functions for both new construction and retrofit applications, including:

  • Scrolling LCD display of kilowatt-hour (kWh) usage
  • kWh in dollars
  • Current electrical demand load in kilowatts (kW)
  • Cost per hour, based on current load
  • Estimated CO2 emissions in pounds, based on DOE standards
  • Estimated hourly CO2 emissions based on current load
  • Net metering, including utility-delivered vs. user-received power and net usage
  • Compatibility with BACnet, Ethernet, LonWorks, Modbus and other leading building automation system communication protocols
  • Compatibility with pulse-output utility meters, including water, gas, BTU, steam, etc.
  • Optional integration with automatic meter reading (AMR) systems for billing and analysis
  • Optional presentment of energy usage and carbon footprint data via easy-to-understand dashboards accessible from any standard web browser, both for single building and campus-wide meter networks.

Ravenscroft's decision to install advanced metering (Figures 3 & 4) was based on feedback from both internal and external sources. One Ravenscroft parent, Joe Hirl, is also an electrical/nuclear engineer and veteran energy-industry consultant. "The perspectives of medium and large energy users are changing as they relate to energy use and environmental impact," says Hirl. "There is more demand to be efficient, but also a requirement to be smart on capital outlays to improve efficiency. Consumers are now inundated with calls from service and equipment providers claiming to have the best energy-saving solution. In reality, companies need to first truly understand how they are currently using their energy before they jump on a 'single' solution."

Figure 3. One of ten Class 3400 E-Mon D-Mon meters monitoring 400A to 3200A circuits in seven campus buildings. The meter's Modbus IP communication option allows direct connection to the building management system (BMS) via the Ethernet link plugged into the jack above the meter. The upper jack is the out-bound link to the central monitoring location. The flex conduit beneath the meter brings in the voltage and current readings from the circuit being monitored, in this case the Fine Arts building's consumption and demand profiles.

With that in mind, the Sustainability Committee and the Board of Trustees spearheaded a comprehensive energy audit to benchmark Ravenscroft's gas and energy use in seven major buildings on campus. The findings of this study triggered the recommendation to meter, a decision that was rubber-stamped by the interdepartmental management team guiding the project through to completion. Key decision makers included:

  • Doreen Kelly, Head of Schoo
  • Vic Bell, Chairman of the Board of Trustees
  • Leonard Johnson, Assistant Head of School for Business and Finance
  • John Replogle, Sustainability Committee
  • Chris Farrow, Joel Williams, Charles Winston and Bob Wright; Buildings and Grounds Committee
  • Munther Qubain, Finance Committee
  • Joe Hirl, Agilis Energy
  • Robbo Newcomb and Kent Woodard, Newcomb and Company

Figure 4. Ravenscroft staffer Johnny Jernigan adjusts mounting of the E-Mon D-Mon meter installed in a campus building. The thin black cable plugged into the jack at the top of the photo is how the meter data is transmitted back to the monitoring location.

Metering System Supplies The Data

Based on recommendations of Ravenscroft parents Robbo Newsomb and Joe Hirl, E-Mon D-Mon was chosen over the local utility's solution of interval data recording (IDR) meters. As it turned out, the local utility's data recording meters lacked the ability to integrate with the school's building management system (BMS) for a centralized way to monitor the school's energy load. Consequently, they were also incapable of functioning as a teaching tool for educating students and faculty on Ravencroft's on-going energy conservation initiatives.

Newcomb and Woodard started the ball rolling with their local stocking distributor, Eck Supply, whose Mark Wiese contacted the E-Mon factory rep, Emery Electrical Sales. Emery's Jerry Helms coordinated with Wiese to work out out pricing, delivery and other issues relative to delivering the metering system elements in a timely fashion for installation.

In operation since May 2010, the hardware and software system installation and startup was completed over a period of about three months by a local electrical contractor, Classic Electric Service, Inc.

The data collection capability of the submetering system is provided by ten E-Mon D-Mon smart meters with Modbus IP communication. The circuits being monitored include 277/480 volt, 3-phase services ranging from 400 to 3200 amps (Figure 5). Additionally, a Web-Mon Enterprise system is being integrated into a campus-wide Tridium Niagara AX platform building management system (BMS) to provide Internet browser-based real-time and historical dashboards of all meters in the system. The meter data is collected both wirelessly and hard-wired and is being stored on the school's network, which is able to accommodate up to 3,000 data records.

Figure 5. Scrolling display of the E-Mon D-Mon meter mounted in the Library & Tech Center shows a total of almost 478,000 kWh of monitored electrical consumption since the meter was installed.

Building Management System

In parallel to the metering system, Newcomb and Company, a full-service industrial, commercial and residential mechanical contractor, installed and conducted training for the school's building management system, a Tridium Niagara AX platform which supports standard open protocols like LonWorks, BACnet and Modbus, to integrate lighting controls, electrical switchgear, generator packages and other building systems into a total facility management system.

The NiagaraAX software framework is especially useful for device-to-enterprise applications, allowing non-programmers to build powerful apps in a drag-and-drop environment. This allows Internet-enabled products like E-Mon's Web-Mon meter dashboard and energy monitor to provide real-time and historical displays of kWh, kW and other measurements via standard Web browsers from any access point in the system.

According to Leonard Johnson, Assistant Head of School for Business and Finance, the whole point of the exercise was to find a way to "monitor individual building energy consumption by time period and then utilize that data in combination with the installation of a Building Management System to reduce energy consumption. The BMS in conjunction with our metering system allows us to do just that."

Results and A Look Forward

In terms of positive impact on operations, "our enhanced understanding of usage patterns and variations have helped drive decisions to perform a lighting retrofit and measure the results," says Johnson. "In addition, the meters have provided the rationale for investing in upgraded building management systems across some of the larger buildings."

Operationally, everyone agrees that the BMS and E-Mon metering system have performed well and as expected. The school is now in the process of interfacing the metering system with Ravenscroft's campus-wide Tridium Niagara AX platform in order to make both the energy monitoring and building management systems accessible to the educational curriculum.

As a teaching tool, Ravenscroft teachers can now use the meter dashboards to demonstrate how energy consumption is being monitored. By comparing historical energy consumption data with current levels, the students are able to contrast the facility's original energy consumption data before the meters were installed with its current savings in terms of energy units, dollars and reduced carbon emissions. One teacher has taken it a step further and tags certain energy-consuming items in his building and manually shuts them down so the students can easily monitor the reduction in energy use and carbon.

Beyond that, notes Johnson, "the data is also helping Ravenscroft to establish seasonal energy usage baselines, prioritize upgrades and retrofits and adjust occupied-versus-unoccupied operating hours to reduce energy use and save money without sacrificing the comfort and quality of the classroom environment."

helping to reveal previously invisible savings opportunities. It will be interesting to check back with Bill in a year’s time to see what further progress Ravencroft has made, based on such positive indications early on.

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