Sophisticated features make advanced meters like the E-Mon D-Mon Class 3200/3400/5000 Smart Meters and others even more useful for the measurement and verification (M&V) role as LEED evolves. Though v4 debuted in fall 2013, projects may still be registered under v3 until summer 2015.
With some 47,000 commercial and institutional projects now underway in 50 states and 120 countries, the United States Green Building Council's "Leadership in Energy and Environmental Design" (LEED®) building-performance assessment system is the facility landscape's dominant market player. Since its inception in 1993, LEED has come a long way toward generating industry-wide awareness and acceptance of green design, operations and maintenance through development of guidelines to help facility professionals navigate through complex sustainability projects. Consequently, many jurisdictions now offer tax credits and other incentives for new construction and retrofit projects incorporating LEED design and construction principles, from government building and commercial skyscrapers to neighborhoods and single-family homes.
LEED v4 Debuts Advanced Metering Requirements
According to the USBGBC, "The hallmark of LEED is its continuous improvement and development cycle that enables the rating system to increase in scope and stringency as new technologies emerge, the needs of the marketplace expand and the understanding of building science and our environmental priorities deepen." As successor to LEED 2009 — which remains in force until June 1, 2015 — LEED v4 aims to enhance the user's experience by providing, among others, additional performance management features to help projects measure and manage energy and water use with finer granularity. Introduced in November 2013 at Greenbuild, LEED v4 raises the bar on previous versions by adding new market sectors, including data centers, warehouses and distribution centers, hospitality, existing schools, existing retail and mid-rise homes. Other changes in LEED v4 consist of revised credit weightings, greater ease of use and increased technical rigor and increasing energy efficiencies across the board. For example, Bosom's Minimum Energy Efficiency Performance prerequisite raised its Energy Star score of 69 in v3 to 75 in v4 — an almost nine percent increase.
Other new prerequisites and credits found in Building Design & Construction (BD&C), Existing Buildings Operations & Maintenance (EBOM) and Interior Design & Construction (ID&C) will provide fertile ground for advanced metering, especially in the Energy & Atmosphere (EA) and Water Efficiency (WE) categories.
Table 1 lists the EA and WE credit areas that are new to LEED v4, in which submeters and other data collection devices will now be needed for:
• Building-level Energy Metering - intended to support energy management and identify opportunities for additional energy savings by tracking facility-level use, this new EA prerequisite impacts a broad range of facility types under the BD&C and EBOM rating systems. Requiring permanently installed metering capable of aggregating whole-facility energy use, including electricity, gas, water, steam, chilled water, BTU and more; this new prerequisite requires minimum monthly or utility-billing-period interval data of consumption (kWh) and demand (kW). Data must be shared with the USGBC for five years, with certain caveats applying. Applicable to BD&C and EBOM, the latter system also accepts manual or remote meter readings and requires monthly and annual summary data reports.
• Advanced Energy Metering — similar in intent to building-level energy metering objectives, the Advanced Metering credit raises the bar by requiring substantially greater granularity of meter data across a range of BD&C, EBOM and ID&C-impacted facility types, as shown in the table. In addition to whole-building metering, any particular energy use representing 10 percent or more of the facility total must also be metered. Moreover, the Advanced Metering credit requires the permanent installation of meters capable of 60-minute or less consumption (kWh) and demand (kW) interval data, remote communications and interface capability to a LAN, building automation system, wireless network or other advanced communication infrastructure. In addition to remote data access, the system must be capable of reporting hourly, daily, monthly and annual energy use and providing data storage for at least 36 months.
• Demand Response (DR) — intended to increase participation in DR technologies and programs that make energy generation and distribution systems more efficient, increase grid reliability and reduce greenhouse gas emissions. Impacting the BD&C and EBOM rating systems, points are given based on level of implementation: not available but has infrastructure in place (1 point) or actual participation in a DR program (3 points).
• Water Metering — with the same intent as above for BD&C projects, one WE credit is given for irrigation, indoor plumbing fixtures and fittings, domestic hot water, boilers, reclaimed water and other process water. In LEED for Healthcare applications, ten additional medical-specific water uses are listed, five of which must also be metered.
• Building-level Water Metering — intended to support water management and identify opportunities for additional water savings by tracking consumption, this new WE prerequisite impacts the BD&C and EBOM rating systems. Although differing slightly in implementation, both rating systems require permanently installed water meters for measuring total potable water use for the building and associated grounds. Water is to be metered at one-month or billing cycle intervals and the data shared with the USGBC for five years. Unlike BD&C, the EBOM system specifies that the meter data may be recorded either manually or remotely and compiled into monthly and annual summaries.
Note that, in addition to the new metering requirements, other meter-related prerequisites and credits descending from LEED v3 and earlier will remain in force, although subject to minor modifications in some cases.
Table 1. Prerequisites and credits for building-level and advanced energy metering, water metering and demand response new to LEED v4. Refer to LEED v3 for other, or earlier metering requirements still in force.
Advanced Metering Capability for LEED v4's Tougher Technical Requirements
Although utility-owned meters capable of aggregating building-level resources are approved for use, utility meter functionality may not be up to the task of meeting the new, increasingly tough metering requirements. Alternately, there are various types of cost-effective smart submeters commercially available that will do the job.
Three main types of meters predominate. As shown in Table 2, the first two — feed-through and current transformer (CT)-based — are socket-type meters. CT-style socket meters are used with loads of 400A and above. In commercial applications, they may be specified but will require more space in the electrical room due to the need for CT cabinets and the meter bases. Another disadvantage in many jurisdictions — socket meters are not UL listed. The third type is the electronic submeter, a non-socket device that provides clear advantages over the previous two, as the right-hand column of Table 2 shows.
In response to the new advanced metering requirements of LEED and other building performance assessment systems, new three-phase, multi-function Ampere/volt demand meters for commercial, industrial and multi-family branch circuit monitoring applications are beginning to appear on the commercial market. Some of these new metering devices offer unprecedented flexibility, in that the same unit can accommodate any combination of single- or multi-phase inputs totaling 36 channels. Accordingly, this permits configuration of up to three dozen single-phase, 18 two-phase, 12 three-phase, or other load combinations up to the device's maximum input capability. No external power supply is needed; for example, the E-Mon D-Mon Multi-Mon smart meter's three phases and neutral are fed by the measured voltages.
Table 2. Non-socket type electronic submeters are less expensive initially, quicker and easier to install and offer superior performance and options versus other types.
Smart meters offer system designers and end users a monitoring solution that OEMs can easily integrate with their own equipment to provide advanced energy monitoring, power quality and communications at the branch circuit level. This capability will be especially valuable in bringing greater granularity of energy intelligence to existing building systems and will cut down on metering bill of materials, facilitate greater energy savings, and lower operating costs through optimized electrical system performance. For example, the Multi-Mon multiple branch circuit energy monitor offers a choice of DIN rail mounting inside the branch circuit panel or an optional steel enclosure (consult E-Mon for details) for mounting adjacent to the panel. Available in both delta and wye configurations, solid- and split-core current sensors are available from 100 to 1200A and are ordered separately allowing maximum flexibility for current sensor and phase combinations. As such, the Multi-Mon provides an off-the-shelf, "custom standard" solution for just about any branch circuit or multiple load monitoring need (Figure 1).
E-Mon's Multi-Mon Branch Circuit Energy Monitor
Figure 1. Advanced submeters like E-Mon's Multi-Mon multiple branch circuit energy monitor offer an OEM packaging solution that system designers and end users can easily integrate with their own equipment to provide advanced energy monitoring, power quality and communications at the branch circuit level. This capability will be especially valuable in helping users to meet LEED v4's new requirements to acquire greater granularity of energy intelligence and communicate it to the building automation system (BAS).
Key features offered by advanced smart meters can include:
- Multiple configurations available as either stand-alone meters, such as E-Mon D-Mon Smart Meters Class 3200/3400/5000 or multi-channel operation — any combination of single-, two- and three-phase loads can be monitored up to 36 total current inputs such as Multi-Mon.
- Industry standard communication protocols allow for integration into software for billing and analysis (E-Mon Energy) and building management/automation systems (BAS/BMS). Available protocols include Modbus RTU, Modbus TCP/IP, BACnet IP, BACnet MS/TP, LonWorks, EZ-7 E-Mon Energy, etc.
The availability of so many flexible communication options greatly extends the submeter's value for building automation and controls applications by enabling input of an expanded range of electrical measurements into the facility's measurement and control system. This benefits the facility by increasing the granularity of electrical measurements that can talk to the BAS via RS-485, LAN, twisted pair, power line carrier, Internet and other compatible media.
Project teams contemplating certification under the LEED v4 rating system will note that advanced metering capabilities are necessary for meeting the Building-level Energy Metering prerequisite, as well as obtaining EA credits for Advanced Energy Metering and Demand Response under the BD&C, EBOM and ID&C rating systems described earlier.
Energy Monitoring Is Worth the Investment
As the primary energy data acquisition "front end" for LEED and other green building rating systems, submeters are installable at key building locations to provide "before, during and after" monitoring and reporting of various building systems, equipment and circuits of interest. In post-certification scenarios, metering provides an on-going hedge against losing visibility on potential energy saving due to staff changes, equipment replacement, shifting utility rate structures and other changes in the facility's operational dynamics.
Advanced energy metering can provide facility managers with easy access to granular energy data, which is especially valuable in light of the more stringent requirements of LEED v4. As a scalable, easily installed data acquisition solution to help identify saving opportunities over the course of the facility's operational lifetime, submeters easily justify their installed cost as essential elements of the increasingly rigorous — and on-going — M & V process at the heart of today's evolving green building rating systems.
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