Measurement and verification (M&V):

Verification is the range of checks and tests carried out to determine whether components, subsystems, systems, and interfaces between systems operate in accordance with the contract documents.

 

Measurement and verification of a building’s ongoing energy use optimize performance and minimize the economic and environmental impacts associated with its energy-using systems.

 

The benefits of optimal building operation, especially in terms of energy performance, are substantial. The lifetime of many buildings is longer than 50 years, and so even minor energy savings are significant when considered in aggregate. Potential long-term benefits often go unrealized because of maintenance personnel changes, aging of building equipment, and changing utility rate structures. Therefore, it is important to institute M&V procedures and continuous monitoring to achieve and maintain optimal performance over the lifetime of the building. The goal of M&V activities is to provide building owners with the tools and data necessary to identify systems that are not functioning as expected and thus optimize building system performance.

3.1 Introduction

IPMVP Volume III provides a concise description of best practice techniques for verifying the energy performance of new construction projects. Chapter 2 describes the process for developing the theoretical baseline for new construction projects and provides examples of relevant applications. Chapter 3 describes the basic concepts and structure of the measurement and verification plan. Chapter 4 describes specific measurement and verification methods for energy conservation measure isolation (Option B) and whole-building calibrated simulation (Option D). Volume III pertains to new construction projects; Volume I relates to retrofit projects in existing facilities.

This document is intended to provide the basic framework for M&V for new construction. While some technical detail is offered, the reader is referred to two other key resources: IPMVP Volume I and ASHRAE Guideline 14, for guidance on specific topics such as statistical issues and instrumentation.

 

Measurement and Verification for New Construction

M&V Option

Baseline Energy Use

Typical Applications

A. Partially Measured Retrofit Isolation

Savings are determined by partial measurement of the energy use of the system(s) to which an ECM was applied, separate from the energy use of the rest of the facility. Some parameters are stipulated rather than measured.

Projected baseline energy use is determined by calculating the hypothetical energy performance of the baseline system under post-construction operating conditions.

Lighting system where power draw is periodically measured on site. Operating hours are stipulated.

B. Retrofit Isolation

Savings are determined by full measurement of the energy use and operating parameters of the system(s) to which an ECM was applied, separate from the rest of the facility.

Projected baseline energy use is determined by calculating the hypothetical energy performance of the baseline system under measured post-construction operating conditions.

Variable speed control of a fan motor. Electricity needed by the motor is measured on a continuous basis throughout the M&V period.

C. Whole Facility

Savings are determined at the whole-building level by measuring energy use at main meters or with aggregated sub-meters.

Projected baseline energy use determined by measuring the whole-building energy use of similar buildings without the ECMs.

New buildings with energy-efficient features are added to a commercial park consisting of buildings of similar type and occupancy.

D. Calibrated Simulation

Savings are determined at the whole-building or system level by measuring energy use at main meters or sub-meters, or using whole-building simulation calibrated to measured energy use data.

Projected baseline energy use is determined by energy simulation of the Baseline under the operating conditions of the M&V period.

Savings determination for the purposes of a new building Performance Contract, with the local energy code defining the baseline.

 

IPMVP Volume III presents 4 options for new construction M&V. Of these, Options B and D are appropriate for LEED M&V.

 

3.2 M&V Processes and Planning

 

 

Energy savings in new construction M&V are determined by comparing measured or projected post-construction energy use to the projected energy use of a baseline under similar operating conditions. In general:

Energy Savings =Projected Baseline Energy Use-                   Eq.1

Post-Construction Energy Use

Post-Construction Energy Use is the energy use of the as-built equipment, system, or building.

This equation is analogous to the retrofit relationship Eq. 1 presented in Chapter 3.1 of the IPMVP Volume I, as follows:

Energy Savings = Baseline Energy Use - Post-Retrofit Energy Use          Eq.2

Adjustments

In new construction the "adjustments" do not stand alone. Instead, the baseline is adjusted to account for operating conditions during the M&V period and the Projected Baseline Energy Use is generated. The adjustments are derived from identifiable physical facts such as weather, occupancy, and system operating parameters. The equation can also be used to estimate demand savings by substituting "energy" with "demand".

 

Measured Post-Construction Energy Use can be determined at the ECM, building system, or whole building level as required. This can be accomplished by one or more of the following methods:

·       Utility invoices or meter readings

·       System sub-metering

 

Responsibility for the design, coordination, and implementation of the M&V program should reside with one entity of the building design team. The person or persons responsible for energy engineering and analysis are usually best-placed for this role.

A complete M&V plan should include, but not be limited to:

·       Documentation of the design intent of pertinent ECMs or energy performance strategies.

·       Statement of M&V objectives and description of the project context of the  M&V program eg. performance contract, incentive-based design fees, etc.

·       Technical identification of the boundaries of savings determination eg. Piece of equipment, system, or whole-building. The nature of any energy effects beyond the boundaries may be described and their possible impacts estimated.

·       Clear statement describing M&V period.

·       Documentation and specification of the baseline including a listing of all important assumptions and supporting rationale

·       References to relevant sections of any energy efficiency standard or guide used in setting the baseline.

·       Specification of the M&V Option or combination of Options, which will be used to determine savings, including a rationale for the choice. If Option D is to be used:

·       Specification whether Method 1 or Method 2 will be used for savings estimation;

·       Specification of the approach to be used if the estimation of long-term savings is required.

·       Specification of analytical techniques, algorithms, and/or software tools (name and version number), including any stipulated parameters or operating conditions and the range of conditions to which the techniques, algorithms, and/or software tools apply (eg. a simulation tool calibrated to summer conditions may not be valid for winter conditions).

·       For Option A, description of the overall significance of stipulated parameters relative to the total expected savings with description of the uncertainty inherent in the stipulation.

·       Final input/output files for software tools, including important assumptions and any unusual modeling techniques employed during the development of the model.

·       Specification of metering points, equipment, equipment commissioning and calibration, and measurement protocols, including expected accuracy.

·       Specification of the methods to be used to deal with missing or lost metered data.

·       Identification of operational conditions that are to be monitored, and methods for monitoring and data collection eg. weather, occupancy, system operating parameters.

·       For Option C, identification of similar buildings to be used to determine Projected Baseline Energy Use, including rationale for the choice with supporting data on building function, location, and operation.

·       For Option D, specification of simulation calibration procedures, calibration parameters, frequency of measurement of calibration parameters, and calibration accuracy objectives.

·       Specification of the set of conditions used for weather adjustments, including the period and/or weather data used, and any assumptions or interpolations made in the case of missing or incomplete data.

·       Expected overall M&V accuracy and anticipated areas of error susceptibility and magnitude of the sensitivity.

·       Description of Quality Assurance procedures.

·       Specification for reporting format of the results.

·       Specification of the information and data that will be available for third party verification, if required.

·       Budget and resources for the entire M&V program, including long term costs, broken out into major categories.

 

3.3 Option B and Option D for LEED M&V

The M&V plan should be based on the owner’s needs and described in the owner’s project requirements. Other implementation issues are the availability of a building automation system and whether the local utility uses meters that provide hourly or minute by minute power consumption data.

 

Option B addresses M&V at the system or energy conservation measure level. This approach is suitable for small and/or simple buildings that can be monitored by isolating the main energy systems and applying Option B to each system on an individual basis. The savings associated with most types of energy conservation measures can be determined using Option B. However, since each measure may require a meter, the limiting consideration may be cost associated with increased metering complexity. Greater certainty in determining savings, particularly with variable loads, often warrants the higher cost.

 

The energy savings may be determined from simple spreadsheet calculations using metered data. Deficiencies and operation errors can often be identified at this time. Usually, the ongoing cost of implementation for this option tends to be lower, because once the meters are installed, they provide continuous performance monitoring. Once the system or tracking is in place, monitoring requires minimal effort.

Option B is best applied in these circumstances:

·       Interactive effects between energy conservation measures or with other building equipment can be measured or assumed to be insignificant.

·       The parameters that affect energy use are not complex or excessively difficult or expensive to monitor.

·       If measurement is limited to a few parameters, this option is less costly and is preferable to simulating operation under Option D.

·       Meters can serve a dual purpose; for example, submetering is used for both operational feedback and tenant billing.

·       Projected baseline energy use can be readily and reliably calculated.

 

Option D addresses M&V at the whole-building level. This approach is most suitable for buildings with a large number of energy conservation measures or interacting systems, such as those related to the building envelope. The performance of triple-glazed windows, air infiltration control, and highly insulated or mass wall systems is difficult to measure and requires computer simulation. An owner or institution wishing to analyze the effectiveness of such conservation measures should choose this option. Whole-building calibration compares the actual energy use of the building and its systems with the performance predicted by a calibrated computer model (like that developed for the energy simulation model used for EA Credit 1, Option 1). Calibration is achieved by adjusting the energy simulation model to reflect actual operating conditions and parameters. Next, the conservation measures are removed from the model to define the baseline. The energy savings are determined by subtracting the baseline energy simulation from the actual energy use.

Option D is useful in these circumstances:

·       Calibration of the as-built energy simulation model shows how interactive energy conservation measures affect building energy use.

·       Calibration of the as-built energy simulation model develops a breakdown of energy use. The breakdown of specific systems and equipment depends on the simulation software used. The advantages to this breakdown are discussed in the Performance Measurement credit of USGBC’s Green Building Operations & Maintenance Reference Guide.

·       A breakdown of energy end uses can help determine the most effective areas for energy conservation, such as electrical lighting versus gas water heating.

·       The comparison of the calibrated as-built model with the calibrated baseline can show the payback of the capital costs of multiple, interactive conservation measures, such as a continuously insulated wall plus triple-glazed windows.

 

The M&V plan identifies the options to be applied, defines the baseline (or how it will be determined), identifies metering requirements, and outlines specific methodologies associated with implementing the plan. Responsibility for the design, coordination, and implementation of the M&V plan should reside with 1 entity of the design team. The person(s) responsible for energy engineering and analysis is usually best suited for this role, although third-party verification may be appropriate in some cases. Since the pursuit of this credit is largely affected by the option selected to achieve EA Credit 1, Optimize Energy Performance, the baseline definition will vary. For EA Credit 1, Option 1, ASHRAE 90.1-2007, Appendix G, defines the baseline. The baselines for EA Credit 1, Options 2 and 3, are defined by the respective prescriptive standards, which (in some cases) may be effectively the same as the design. In that case, the M&V plan addresses design performance only. However, it is necessary in all cases to predict the energy performance of the design and/or its systems. For Option B, this can be accomplished through either computer modeling or engineering analysis, depending on the complexity of the systems.