Services & Maintenance: Energy Measurement And VerificationContributor John Schinter discusses how facility management professionals can track and use their data.By John Schinter A facility management (FM) department operating a corporate portfolio of buildings in the U.S. spent nearly $30 million on energy costs in 2005. This organization was able to reduce its energy usage by more than 7% in the three years that followed, helping to keep costs stable at a time when some regions were seeing 20% rate hikes.
M&V Guidelines And ResourcesThere are many ways to measure and verify energy efficiency. Engineers generally equate M&V with the Efficiency Valuation Organization’s (EVO) International Performance Measurement & Verification Protocol (IPMVP) as a way to measure systems in isolation or to conduct whole building comparisons (see sidebar for more on EVO). Regarding new buildings, in March 2008, the New Buildings Institute based in Vancouver, WA concluded a study funded by the USGBC, with support from the EPA, on the energy performance of LEED for New Construction (NC), version 2 buildings. Of the 552 LEED certified buildings invited to participate in the study, management in 250 of those was willing to supply information, but only 121 could supply the energy usage data typically found on monthly bills. The International Performance Measurement Currently, the EVO-owned International Performance Measurement and Verification Protocol (IPMVP) is a leading international standard in M&V protocols. The IPMVP is a widely referenced framework for measuring energy or water savings. It is especially used in energy performance contracts where savings must be reported to a client and may form the basis of a payment to an energy services company (ESCO). M&V activities can include site surveys, metering of energy or water flow, monitoring of independent variables, calculation, and reporting. Definitions The IPMVP includes numerous definitions for users to reference in their M&V efforts. Following are several terms mentioned in this article. A full list can be found in the IPMVP literature on the EVO’s Web site (see end of article). Baseline Period. The period of time chosen to represent operation of the facility or system before implementation of an ECM. This period may be as short as the time required for an instantaneous measurement of a constant quantity, or long enough to reflect one full operating cycle of a system or facility with variable operations. Energy Conservation Measure (ECM). An activity or set of activities designed to increase the energy efficiency of a facility, system, or piece of equipment. ECMs may also conserve energy without changing efficiency. Several ECM’s may be carried out in a facility at one time, each with a different thrust. An ECM may involve one or more: physical changes to facility equipment; revisions to operating and maintenance procedures; software changes; or new means of training or managing users of the space or operations and maintenance staff. An ECM may be applied as a retrofit to an existing system or facility, or as a modification to a design before construction of a new system or facility. Measurement Boundary. A notional boundary drawn around equipment and/or systems to segregate those which are relevant to savings determination from those which are not. All energy uses of equipment or systems within the measurement boundary must be measured or estimated, whether the energy uses are within the boundary or not. Savings. The reduction in energy use or cost. Physical savings may be expressed as avoided energy use or normalized savings. Monetary savings may be expressed analogously as “cost avoidance” or “normalized cost savings.” Savings, as used in IPMVP, are not the simple difference between baseline and reporting period utility bills or metered quantities. Measurable Action The IPMVP provides four options (A, B, C, D) for FM professionals to determine savings. Choosing which option to use for M&V of a project involves a number of considerations including the location of the measurement boundary. For instance, option C or D may be favored if the facility manager (fm) wishes to determine savings at the facility level. However, if only the performance of an energy conservation measure (ECM) itself is of concern, a retrofit isolation technique may be more suitable (option A, B, or D). Following are brief explanations of each of the four options that can be used to determine energy savings, as contained in the 2007 edition/Volume 1 of the IPMVP from EVO. A. Retrofit Isolation: Key Parameter Measurement. Savings are determined by field measurement of the key performance parameter(s) which define the energy use of the ECM’s affected system(s) and/or the success of the project. Measurement frequency ranges from short-term to continuous, depending on the expected variations in the measured parameter and the length of the reporting period. An example of an application would be a lighting retrofit where power draw is the key performance parameter that is measured periodically. Users estimate operating hours of the lights based on building schedules and occupant behavior. B. Retrofit Isolation: All Parameter Measurement. Savings are determined by field measurement of the energy use of the ECM-affected system. Measurement frequency ranges from short-term to continuous, depending on the expected variations in the savings and the length of the reporting period. An example of when this approach would be used is in the application of a variable-speed drive and controls to a motor to adjust pump flow. Users measure electric power with a kW meter installed on the electrical supply to the motor, which reads the power every minute. In the baseline period, this meter is in place for a week to verify constant loading. The meter is in place throughout the reporting period to track variations in power use. C. Whole Facility. Savings are determined by measuring energy use at the whole facility or sub-facility level. Continuous measurements of the entire facility’s energy use are taken throughout the reporting period. A typical application would be a multifaceted energy management program affecting many systems in a facility. Energy use is measured with the gas and electric utility meters for a 12 month baseline period and throughout the reporting period. D. Calibrated Simulation. Savings are determined through simulation of the energy use of the whole facility or of a sub-facility. Simulation routines are demonstrated to model actual energy performance measured in the facility adequately. (This option usually requires considerable skill in calibrated simulation.) This approach is typically used in a multifaceted energy management program affecting many systems in a facility but where no meter existed in the baseline period. Energy use measurements, after installation of gas and electric meters, are used to calibrate a simulation. Baseline energy use, determined using the calibrated simulation, is compared to a simulation of reporting period energy use. The IPMVP is currently in its fourth edition and can be downloaded at www.evo-world.org under the Products & Services tab. IPMVP is prepared in three Volumes: Volume I, Concepts and Options for Determining Energy and Water Savings; Volume II, Indoor Environmental Quality (IEQ) Issues; and Volume III contains specific application guidance manuals for Volume I. The EVO has offices based in Washington, DC. Do you have experience with IPMVP? Send an e-mail to avazquez@groupc.com. Drilling Down As Far As NeededThe key to successful M&V is to gather information on each building on a timely basis in a program that automatically translates the data into a series of on-demand charts and graphs. Visually expressed, the relevant data can be viewed on one computer screen—an interface known as a dashboard—for any type of information, time period, and level of stakeholder, from concise overviews for corporate and business unit leaders to detailed single facility assessments for fms. The dashboard data also facilitates accounting procedures for the organization by integrating with bill processing and payment firms for automatic uploading of information. As president of energy and sustainability services at Jones Lang LaSalle (JLL), Schinter directs teams with the goals of reducing energy use in facilities, saving money, and avoiding greenhouse gas emissions. He has worked with JLL teams on 116 completed or current LEED projects totaling more than 35 million square feet worldwide. Schinter was named 2008 Energy Engineer of the Year by the Association of Energy Engineers (AEE). He can be reached at john.schinter@am.jll.com. (Image credits: Photo (JupiterImages); Chart (New Buildings Institute)) To download a copy of the New Buildings Institute report mentioned in this article, visit www.newbuildings.org/research.htm and go to “LEED Energy Performance Project.” Are you tracking the results of your energy management actions? Send an e-mail to avazquez@groupc.com. |
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