4  FM quick reads on meters

1. How to Customize Sub-Metering Systems

This is Chris Matt, Managing Editor of Print & E-Media with Maintenance Solutions magazine. Today's tip is customizing sub-metering systems.

Each facility produces a unique energy-load profile with specific circuits and systems that would be advantageous to monitor. Managers should customize sub-metering systems to provide maximized benefits and flexibility for the facility. A well-designed sub-metering system also allows for future scalability to meet changing energy use and demand needs.

The advantage of sub-meters is that managers can install them easily in both new and existing facilities. They are much lower in cost compared to most utility-scale master primary meters. An electrician typically can install a sub-meter in about three hours.

Managers also can easily integrate the meters into an electrical-distribution system without having to make major interior or equipment changes in the building. Installation is as easy as connecting current sensor clamps around each phase of electrical feeders and adding potential taps.

The average cost to buy and install a sub-meter and control wiring connected to a building-automation system is $1,500-$2,500 per control point. Managers also might consider additional funding measures from local utility companies.

To ensure effective installation, managers also can properly maintain the sub-meters by implementing initial commissioning and preventive maintenance plans.

Technicians should check communication gateways and networking to ensure each control wire in the system functions and interacts within the system properly. For new projects or retrofits, employ a commissioning agent for quality control and to ensure building meters and metered systems are designed, installed and calibrated to operate as intended. The unit should deliver data managers and technicians can access easily, possibly via the Internet or another web-based platform.

2.  Focus on Energy Efficiency: Sub-Metering Strategies

This is Chris Matt, Managing Editor - Print & E-Media with Maintenance Solutions magazine. Today's tip is using sub-metering to manage energy use.

The first step in sifting through sub-metering technology is to identify the organization's essential energy-management needs and determine the way the facility can address these needs with a data-collection system.

The type of energy information many facilities require often is beyond the capability of one master utility meter. Sub-metering systems, combined with useable and comprehensive data-collection systems, can give managers much more detailed load profiling. Managers can use the collected data to:

• understand energy-use patterns and trends
• implement demand response and control to avoid costly ratchet and peak utility charges
• profile an entire facility for demand-management and load-shedding measures
• locate true spare capacity within the electrical system.

In its simplest form, sub-metering involves installing separate meters downstream of the primary billing meter. These meters monitor specific points in the system. In campus settings, for example, sub-meters might be set up on a building-by-building basis to allocate energy costs among departments. In single buildings, managers can group specific system circuits and monitor the distribution system to minimize the number of sub-meters.

Some sub-meters can transfer data, while others also can record and store interval data. Other intelligent-breaker technologies allow system operators to control individual circuits in a distribution system separately, as well as monitor the system's data separately.

At a minimum, managers should install sub-meters on lighting, HVAC, alternative-energy systems, and other key pieces of equipment, which will produce the most valuable trending data. Managers can reconfigure and display this data to the building occupants and visitors with a energy dashboard that presents the information in a way they understand.

3.  Sub-Meters Monitor HVAC Components

This is Chris Matt, Managing Editor of Print & E-Media, with Maintenance Solutions magazine. Today's tip is sub-metering and energy efficiency.

One area in which sub-metering technology excels is measurement and verification. Since technicians can install a sub-meter almost anywhere in the electrical-distribution or branch-circuiting system, managers can specify meters for use in areas in which they are most effective in gathering useful energy information. For managers in a large facility who want to understand the building's overall energy profile, these meters can help by monitoring individual pieces of equipment, including chillers, pumps, air handlers, and other HVAC-system components.

By collecting this data, managers can identify operational inefficiencies. Often, this step can reveal interesting trends, such as two or more large motor loads starting at the same time, which causes system spikes. By alternating or staggering these loads, managers can eliminate spikes and improve efficiency.

Sub-meters also can alert front-line technicians to the potential failure of a piece of equipment before it fails. Monitoring the current draw on a piece of equipment generates a profile. Once that piece of equipment starts to draw more than the recorded profile current, technicians can program an alert to let them know a potential problem exists. The technology allows technicians to take preventive measures before a costly failure occurs, and the resulting savings in downtime and maintenance costs can more than pay for installation of the sub-meters.

4.  Benefits of Submetering Central Plant Can Justify Cost

Today's topic is the value of submetering the central plant.

The chiller plant is likely to be one of the facility's largest energy users, and often the largest. That makes it a good candidate for submetering.

The biggest obstacle to submetering is typically cost. But submetering the chiller plant offers a range of important benefits that can justify the cost. Perhaps most important is that it enables facility managers to analyze the energy consumption of the central plant. For example, if chiller plant energy use climbs from one spring to the next, it may be that outside air economizers aren't working properly. Or a change in operations or a problem with controls may have caused a spike in electricity use. Addressing problems like those can bring significant savings.

Data from submeters can be used to test the effectiveness of various operational measures designed to save energy and to verify whether upgrades have actually performed as expected.

What's more, submetered data may help to identify problems with equipment. Addressing those problems may not only save energy, but prolong the life of the equipment or identify a piece of equipment that is failing.

Finally, in a multitenant building, the use of submeters can be an element in an overall energy efficiency or green strategy used to attract and retain tenants.


meters , sub-meters , energy , energy efficiency , bas , building-automation systems , building automation

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