previous Utilities Metering
1. METER SELECTION: Selection of metering equipment consists of much more than purchasing a meter compatible with the system to be metered. Selection of metering equipment for electricity is greatly simplified as the operating principles of electrical metering devices exhibit little variation compared to fluid metering equipment. Purchasing electric metering equipment basically requires an identification of measurements to be made, the parameters of the system, a decision on remote metering, and selection of a meter that fulfills these requirements. Metering of fluid systems requires additional effort. Figure 2-1 is an example of the system information necessary to optimize a fluid type meter selection. Figure 2-1 used in conjunction with Table 2-1 is an example of an iterative process for proper meter selection. Another selection method recommends the factors shown in Figure 2-2. Whatever criteria selected, they must be tailored to the specific installation to ensure that any problems are fully highlighted in the process. The individuals involved in the selection process must be knowledgeable of the sources to be monitored, the information required, and the capability of the meters being evaluated. Another major consideration is the purpose of the meter: control or accountability. Once the information contained in figures 2-1, 2-2, or other criteria is available, a tentative meter(s) selection can be made. At this point , manufacturers of this type meter should be consulted. Although most manufacturers provide extensive cooperation, their claims should be thoroughly evaluated to insure that a particular choice is optimum for the intended application.
1.1 Permanent and Portable Meters: In establishing an energy management program, the use of permanent or portable meters shall be evaluated. Meter locations must be evaluated individually to ensure accounting for all factors pertinent to meter installation and maintenance.
1.1.1 Fluid Meters: Intrusive flowmeters, particularly differential pressure and positive displacement types, always have some degree of pressure loss associated with their operation. Consequently, if continuous data recording is not required, portable insertion meters may be used for temporary metering. If continuous metered data is required, but pressure losses are a concern, non-intrusive meters should be considered, despite their greater initial costs. Because most permanent meters are pipe size specific, costs increase in proportion to pipe size. Insertion meters do not generally increase in price as pipe size increases, and are generally more economical for larger pipe sizes. Figure 2-3 shows a cost comparison of a permanently installed orifice plate meter versus an insertion type meter. Typically, the cost advantage crossover occurs between the 6- to 8-inch pipe size.
1.1.2 Electric Meters. The usual distinction between panel (permanent) and portable electric meters is whether they are fastened securely to the facility or capable of being hand carried. Most electric meters are made in both
Iterative Approach to Flowmeter Selection
Figure 2-1: Iterative Approach to Flowmeter Selection
  1. What medium is to be measured?
  2. Will meter indications be used for process control or energy accounting?
  3. What physical measurement will be used to determine the flow rate?
  4. What are accuracy requirements?
  5. Are physical space limitations a factor in mounting the meter and any associated equipment?
  6. Are there any environmental conditions at meter site that would limit meter selection?
  7. Can the media flow be turned off for meter installation or must it be a hot insertion?
  8. Must meter maintenance be accomplished with the line hot?
  9. What range of flow must be measured currently and what is predicted flow in the future?
  10. Will data be obtained by direct reading or remote monitoring? If direct reading, is remote monitoring contemplated in future? Ensure meter is compatible.
  11. Is the media flow steady, intermittent, or pulsating? Is there a full pipe flow?
  12. l Can a portable meter be used that will provide adequate measurements and what are the cost advantages?
  13. Identify potential meter selections that meet the requirements listed.
  14. Contact several manufacturers for recommendations.
  15. Ensure such recommendations allow comparisons between various candidates pertaining to purchase and installation costs, operational limitations , maintenance requirements, training requirements, costs related to operation of the meter in the media (pressure drop), and all other factors important to the specific installation being evaluated.
Table 2-1: Characteristics of Flowmeters
Flowmeter Type/Cost Comparison
FIGURE 2-3. Flowmeter Type/Cost Comparison
panel and portable models. The following list indicates model availability.
  • Ammeters--panel and portable.
  • Kilowatthour--panel and portable.
  • Multimeter--portable.
  • Power factor meters--panel and portable.
  • Voltmeters--panel and portable.
  • Watt/demand meters--panel and portable.
1.2 Incremental Installation of Metering Systems: If the management plan envisions a complete metering system consisting of metering devices, data recording, and central or remote control capabilities, it is probable that the system will have to be installed on an incremental basis. If so, the meter criteria (figures 2-1 or 2-2) must take this into account to ensure equipment for each phase is fully compatible and interfaces with the components required to complete the system.
1. METER INSTALLATION CRITERIA. Meters and ancillary equipment should be installed in new or retrofit construction to facilitate management of utilities. Meters shall be installed when the following criteria are met:
(a) New construction—New facilities should be provided with electric, water, and natural gas meters, as appropriate. Steam meters should be provided for new facilities where the annual energy cost component of steam will exceed $50,000.
(b) Energy retrofit programs--Meters shall be installed on Energy Conservation Investment Program (ECIP) projects if the total project SIR is at least 2.5, including the cost of the meters, and if the cost of the meters does not exceed 10 percent of the total cost of the project. Meter costs shall include both hardware and installation. If meter installation cannot be cost-justified for one facility, combining a number of facilities in the analysis may warrant meter use. For Energy Technology Applications (ETAP) projects, meters should be included if desired by the activity and Claimant. Figure 2-4 is an example of how to evaluate a meter installation using these criteria.
(c) Energy-Converting Devices: All energy-converting devices with outputs greater than 20 MBTU/hr or 1,000 kW, such as boilers, turbines, and generators, shall be metered. Metering both input and output is desired, but where cost considerations limit metering to input or output only, select the most useful and cost effective.
(d) Customer Requirements: Meters may be installed at the customer’s request for energy accountability or for project validation.
(e) Public Works Center (PWC)/Public Works Department (PWD) Requirements: Meters shall be installed by the PWC/PWD for billing and energy management.
(f) Preinstalling Meters: Hardware and plumbing may be installed so that portable meters can be used later. If criteria to install permanent meters are not met, the criteria shall be reapplied for portable meter preinstallation. Portable meters can then be installed for spot checking and profiling. Portable meters can also be used to determine whether proposed meter sites meet criteria.
2. METER LOCATION CRITERIA: Meters must be in strategic locations that will provide energy managers with adequate information to control their utility systems. They shall provide information to determine when load shedding is required, identify situations where energy losses can be avoided, verify that procedural changes will result in decreased utility costs, and allow metering of tenants. In selecting locations, preference shall be given to locations that are clean, well-lighted> and minimize damage possibilities. It is also important to select sites where excess heat or other potential causes of faulty readings are absent. The following paragraphs contain recommended locations for meter installation; however, if unusual circumstances exist, some deviation is acceptable providing the metering results do not degrade utility manager’s capability to effectively manage.
A project is approved to replace 50, 1,000-watt mercury lamps with 50, 400-watt sodium lamps in a hangar. Project cost is $10,500 with discounted benefits of $ 34, 969 (project information) . Determine if a meter can be included in this project within the guidelines of paragraph 1(b).
A. Compute SIR, both with and without a meter, and evaluate results.
B. Calculate cost for the completed project and ensure meter costs are equal to or less than 10% of this value .
C. If preceding step is unsuccessful, reevaluate , combining additional facilities.
Cost of installed meter is $2,000.
SIR = Discounted Benefits/Project Cost; SIR must be greater than 2.5.
Procedure A: SIR Test:
SIR (No meter) = $ 34,969/$ 10,500 = 3.33             SIR of 3.33           2.5
SIR (With meter) = $ 34,969/$ 12,500 = 2.80         SIR of 2.80           2.5
SIR remains greater than 1; project will not be jeopardized by meter.
Procedure B: Calculation of 10% Criteria:
Since the meter cost ($ 2,000) is greater than 10% of the project cost $ 1,050) a meter cannot be included in this project,
Procedure C: Meter Justification for Entire Hangar:
Excluding electric costs for the lamps, the daily energy load is determined to be 60kW for 8 hours and 35 kW for the remaining 16 hours.
Costs per year: 1,040 kWh/day x 260 days x 0.06/kWh = $16,224
$ 16.224 + $ 4,992 = $ 21,216
10% x $21,216 = $2,121
$ 2,121 is greater than $ 2,000 (meter cost); therefore, one meter for the entire hangar is justified as it meets both the SIR and 10% criteria.
2.1 Electrical Utilities: Meter locations are as follows:
(a) Meters shall be located at sources of supply, major substation feeders, major loads (piers, industrial loads, and hospitals), and locations where tenant activities can be metered.
(b) Metering shall have the capability of monitoring demand in kilowatts, and total energy in kilowatthours.
(c) Meter taps shall be installed at strategic locations so that portable meters can be used to monitor loads for short intervals.
2.2 Steam Utilities: Meter locations are as follows:
(a) Meters shall be located at sources of supply, the supply end of trunklines, major loads (piers, industrial loads, and hospitals), and locations where tenant activities can be metered.
(b) Trunkline meters shall be of the turbine meter type and have the capability to compensate for pressure and temperature.
(c) Meters taps shall be installed at strategic locations so that portable meters can be used to monitor loads for short intervals.
2.3 Gas Utilities: Meters shall be located at sources of supply, major loads (industrial loads and hospitals), and locations where tenant activities can be monitored.
2.4 Water Utilities: Meters shall be located at sources of supply, major loads (industrial loads and hospitals), and locations where tenant activities can be metered.
3. PRIORITY OF METER INSTALLATION: Meters shall be installed on a priority basis, that rank projects according to the potential savings of utility dollars. Although installations must be evaluated individually, a typical Installation would rank energy costs as follows, which in turn establishes priority ranking for meter installation:
(a) Electricity
(b) Steam
c) High-Temperature Water
(d) Natural Gas
(e) Potable Water
(f) Wastewater

1. MAINTENANCE AND MAINTENANCE RECORDS: Since any metering program relies on accuracy of the information derived , a maintenance, inspection and calibration program must be established. Meters must be tested and calibrated prior to installation and subsequently on a schedule recommended by the manufacturer. Meters monitoring energy sources entering the facility must be calibrated at least annually. Figure 2-5 is an example of a maintenance record form for utility meters. This form can be revised to provide salient information for other types of meters. Skilled technicians must be assigned to maintain and service meters and auxiliary equipment. Personnel without specialized training must be discouraged from trying to correct any problems encountered due to the high cost of this equipment. If skilled maintenance employees are not available, one alternative is a maintenance service contract.
2. CALIBRATION RECORDS: Records of all maintenance, inspection, and calibration actions must be kept to verify the status and accuracy of the meter. Historical records should be reviewed to determine whether calibration is performed frequently enough to maintain meters in good working order. Certain applications may be critical and require more frequent calibration. Conversely, historical records may show that the meters do not need calibration as frequently as presently scheduled.
FIGURE 2-5. Example of a Maintenance Records Form
1. METER DATA: In evaluating the progress of any energy management program, a chronological record of performance must be retained for reference and comparison purposes. Most meter recording devices print information on either a strip chart or as a column of alphanumeric symbols. Numerous computer programs are available that calculate and display trends, variations, and progress toward final goals. If a computer is not available, information can be compiled using a handheld calculator. If meters are not equipped with a recording device, it will be necessary to determine how often the meter information shall be recorded. A form must be developed (Figure 2-6) that will adequately identify and record the pertinent information for subsequent analysis. Recording devices that provide a continual or variable time interval record of meter measurements are essential to an energy management program; but data must be reduced, analyzed, and acted upon regularly to be of any benefit.
1.1 Data Collection: Data must be collected on a regular and consistent basis. Regular data collection keeps personnel familiar with “normal” usage data and helps create a basis or history of utility consumption. Regular data collection is essential to prevent backlogs of raw data that must be reduced.
1.2 Data Reduction: Raw data must be reduced to summarize metered information. It can be tabularized, averaged, maximums and minimums calculated, and graphed to show usage trends and demonstrate the value of energy conservation actions. Using statistical techniques, such as multiple linear regression, data can also be used to construct utilities consumption models . Multiple linear regression produces a utilities consumption model equation by establishing the validity of the relationship between variables that affect utilities consumption (independent variables) and actual utilities consumption (dependent variable). By establishing which variables actually affect utilities consumption, changes in utilities consumption can be understood and anticipated.
1.3 Problem Identification: Regular data collection and analysis allows operating personnel to become familiar with "normal" meter operation and to recognize unusual readings or conditions. This is essential to timely maintenance.
1.4 Reporting: Metered data serves no purpose if it is not distributed to personnel who can effect changes. Consequently, each command should establish a distribution list for meter reports. The distribution list should include the commanding officer, production officer, public works officer, department heads, and work center and production managers. Command and management support is an absolute requirement for a successful metering program.
FIGURE 2-6. Example of Form to Record Meter Data
1. METER CALIBRATION CERTIFICATION FOR PURCHASED UTILITIES: Purchased utilities are a significant cost to Navy activities. Because the utility company usually owns and maintains the utility meter, the activity often has no direct way to verify charges. This problem has been complicated by the advent of digital recording meters that provide no visual readout. Following are methods of verifying charges for purchased utilities:
1.1 Redundant Metering: Utility bill verification at the 100 percent level can be achieved by redundant metering. This requires installation of Navy owned meters in series with those of the utility company. Depending on utility service configuration, one or more meters are required for each purchased utility. Cost of redundant metering must be evaluated with respect to potential benefits before redundant meters are installed. Redundant meter costs include cost of meters and installation, cost of outages to install the meters, cost of reading and analyzing the additional meters, and cost of annual maintenance and calibration.
Most activities have electric meters at major substations. By calculating energy balance, the activity can verify whether utility charges are correct. This option is limited to the extent that meters are installed at an activity, but, because the meters can be used for energy management and in-house billing, this type of redundant metering may be more cost effective than a single redundant meter. Meters should be sited at major trunks to minimize the number of meters required.
1.2 Verification by Historical Usage Data: Utility bills should be checked for discrepancies by comparing historical usage rates to present consumption. The following should be considered:
(a) Based on past billing records, set high and low limits for utility consumption and compare the utility bill to the limits. This is accomplished by evaluating past data for trends and usage patterns and developing a prediction of what utility consumption should be during a specified interval. Significant deviation from predicted usage should be investigated. Multiple linear regression techniques may be useful in developing predictions of utility consumption.
1.3 Utility Procurement Contracts: Utility procurement contracts should be written to meet verification requirements. Utility contracts are renewed yearly and can be modified to achieve this. Contracts should include:
(a) Periodic meter calibration. Calibration should be performed at yearly intervals, or as required by law. In general, the Public Utilities Commission requires regulated utilities to periodically calibrate billing meters. Public Works personnel should require copies of calibration records and should have a government representative present during calibration to ensure that standard calibration procedures are followed.
(b) An analog display, or data logging capabilities should be required on utility meters to provide for Navy verification of utility meter readings.
(c) Utilities companies should be required to upgrade meters to the minimum capabilities needed to accurately meter a particular utility. For example, natural gas meters must be pressure compensated.
1. CATEGORIES OF METERS: Meters discussed in this manual fall under two categories: those used for electric energy and those that measure fluid flow.
1.1 Electric Meters: The basic meters used in an electric energy management program are:
  • Kilowatthour Meter: Measures the total power consumed.
  • Demand Meter: This meter, usually part of a kilowatthour meter, measures the average power consumption over specific time periods.
  • Power Factor Meter: Power factor meters, located where the main service enters the facility, permit continual monitoring of the power factor for the entire installation. The data contribute to computing consumer billing.
  • Power Survey Recorders and Analyzers: Typically monitor and record several parameters such as load power, real power, reactive power, apparent power, power factor, and voltage and current for single-, two-, and three-phase circuits.
  • Ammeters: Used to measure current flow to identify and isolate system or equipment energy losses.
1.2 Steam, Water, and Gas Meters: Steam, water, and gas flowmeters can be categorized by principle of operation, which yields the classifications below. Table 2-1 is a compilation of important parameters for these types of meters.
  • Differential Pressure Meters: These are the most common type meters in use and include orifice, venturi, flow nozzle, and pitot tube. Used to measure the difference in pressure between two points in the system.
  • Positive Displacement Meters: Oscillating piston and nutating disk meters are most often used in the measurement of potable water. Diaphragm meters are used in the measurement of natural gas.
  • Velocity Meters: Turbine, vortex shedding, electromagnetic, and sonic design type meters have widespread application.
  • Open Charnel Meters: This type of meter is used almost exclusively to measure waterflow in open conduits where a full flow is not required. Characteristically, three sides of the flow are bound by some type of wall with the remaining side being a free surface. Typical open conduits include tunnels, nonpressurized sewers, partially filled pipes, canals, streams, and rivers. Meters of this type are weirs and flumes.
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