Energy Efficiency Reference/Industrial/Compressed Air/Collecting Data

Collecting Data

This step of an assessment is performed at the plant. After familiarizing yourself with the equipment and terms involved with compressed air systems, examine plant equipment and identify the type of compressed air system. Data can then be collected for each specific piece of equipment. This section includes data collection tools and methods for gathering standard system data.

Data Collection Tools

• Digital Multimeter: (DMM: Power used by an electric motor can be directly measured or calculated from voltage and amperage. Use a DMM to measure the voltage at the motor starter or control panel. Measure line-to-line or line-to-ground voltages depending on probe placement. Use caution and understand important safety precautions when measuring high voltage.
• Clamp-on Ammeter: Amperage is needed to calculate power. A clamp-on ammeter senses line current by measuring the current induced in the ammeter by the magnetic field produced by the current. Use the clamp-on ammeter to measure the current in all three phases for power calculations. It is important measure amperage at as many operating conditions as possible to allow accurate modeling of equipment operation.
• Power Analyzer: A power analyzer measures and stores power use over time. A 3 phase-power analyzer, for example, has three clamp-on ammeters, three voltage probes, a neutral probe, and a ground probe. Connecting these to the motor leads allows the power analyzer to measure all line-to-line voltages, line-to-ground voltages, all line currents, phase shifts, and to calculate power. Read the instructions carefully to connect leads correctly for the type of power system (delta) or (wye).
• Pressure Gauge: Many are compressors include a pressure gauge on the control panel. For compressors that do not have a gauge use a pressure gauge that fits in to quick disconnect fittings to measure system pressure at several places.
• Capacity Gauge: Many compressors include a capacity gauge that displays the airflow, usually in acfm, that is being delivered. Record the acfm at as many operating loads as possible to accurately model the operation of the compressor. The gauge may be a vacuum gauge that measures air density at a throttled inlet, or be connected to an airflow meter.
• Stopwatch: Useful to measure on/off & load-unload cycles for use factor calculation.
• Rag: Useful to wipe off dirty nameplates.
• Flashlight: Compressors are often located in dark catacombs of the plants. Their location makes reading gauges and nameplates difficult.
• Tape Measure: For pipe, receiver, or duct dimensions.