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Energy Measuring Principle

Heat or energy flow meters are designed to measure heat consumption, heat loss, or energy available within a flow stream. Energy flowmeters consist of two sensors: a flow meter to measure flow and either a single or a pair of temperature sensors. Both flow and temperature information are sent to a system controller, where it calculates the volume heat flow within a pipe. If the requirement is to measure the amount of energy available within a flow stream, a single temperature sensor is used, or, if the application requires monitoring energy usage, then a matched pair of temperature sensors (such as two thermocouples) are used and calibrated together as a pair to make sure that the temperature difference between the input and output of the system is measured.

Flow can be measured by many different techniques such as magnetic, ultrasonic, turbine, or vortex technologies. For the principle of operation of any of the above water flowmeters, please read the principal of operation for the appropriate technology in our flow metering section. Some application examples for energy flow meters are discussed below:


Chiller systems are usually managed by a facility management company. In order to achieve accurate billing, it was necessary to install energy flow meters to accurately measure the energy consumption of each compound. In addition, due to the long pipe lines, it was crucial to know if leakage of water or energy occurred on a real-time basis. Energy flowmeters are the perfect solution in this situation. Energy flowmeters may also be used for water flow for chiller loading optimization, measuring energy flow for chiller performance or optimization, or monitoring of water consumption or chemical rate control. 

Heat Exchangers

Both primary and secondary exchanger efficiency needs to be monitored then optimized; energy flow meters are an excellent solution.

Cooling Towers

Energy tower performance, water flow for load sharing, water that requires replacing dissolved solids by dilution or chemical additive control rates, and cooling towers are primary candidates for our energy flow meters.

Building Automation

Cooling related costs can be as high as 30% of the operational costs of a residential building, hospital, or school. By using energy flowmeters such as the SmartMeasurement™ AlsonicEG  or AlmagEG to measure the flow of water throughout a cooling system, energy flow meters can give facility managers total control over their system, enabling them to dramatically reduce costs and save a substantial amount of money.  Reduced energy costs alone can pay for any investment in less than two years

Temperature and energy flowmeters are used in a variety of interlaced cooling circuits. These applications include airports, hotels as well as office blocks, university facilities, shopping complexes, hospitals and even residential developments.

The SmartMeasurement method

Although the four technologies mentioned above may be used to measure flow, we recommend only ultrasonic or magnetic flow meters for energy flow meter applications.

AlsonicEG family

When a non-intrusive installation solution is required for combined heating and cooling applications, the AlsonicEG ultrasonic technology is the best choice. With its high accuracy, easy clamp-on installation method the AlsonicEG energy flowmeter provides high accuracy energy and flow measurements and measures all types of water such as special treated water with low electric conductivity and magnetite. In buildings where the air-conditioning can’t be turned off, the AlsonicEG energy ultrasonic technology enables retrofitting of transducers under pressure with clamp-on or hot-tap technology, which is a very cost effective solution.

AlmagEG family

For the vast majority of chilled water applications, an electromagnetic technology such the SmartMeasurement™ AlmagEG is the best choice. With its better than 0.5% accuracy, the AlmagEG is used to replace conventional mechanical meters when greater functionality is required.  An integral self-monitoring circuit surveys all functions and gives an alarm in the event of any malfunction.  The AlmagEG is also used in place of the AlsonicEG where there are more than 1-2% bubbles or particles in the flow stream.

Request a quote on the energy flow meters you need, or contact SmartMeasurement to learn more.

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