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.
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.