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Flow Measurement with
Glycol Compensation

Belimo Expands Portfolio with Ultrasonic Flow Sensor

Trusted flow measurement is essential in maximising HVAC system efficiency and ensuring occupant comfort. Belimo’s new flow sensor utilises ultrasonic transit-time technology to provide accurate and repeatable flow measurements of water and water/glycol mixtures without drift in any HVAC application.

The innovative measurement method features:

  • Multi-point wet calibrated to ensure accuracy and repeatability.

  • Patented temperature and glycol compensation logic eliminates manual calibration.

  • ±2% accuracy of reading and ±0.5% repeatability ensure accurate and precise flow measurement.

  • Ultra-compact size with a short inlet length of 5 x nominal pipe diameter and no output-length requirements allow the ultrasonic flow sensor to be installed in tight spaces.

  • Low power consumption of 0.5W saves energy and transformer capacity.

Why is Glycol compensation important?

The addition of glycol is the most common way to protect water-based HVAC systems exposed to freezing temperatures. Adding glycol lowers the freezing point which, also increases the boiling point and has a significant influence on the viscosity, density, and heat capacity of the HVAC systems.
Determining the flow/thermal energy without taking the water temperature and glycol concentration into account could lead to measuring errors. Insufficient or unreliable water temperature readings could distort the heat coefficient by up to 18%. Inaccurate or unknown glycol water compositions may lead to deviations of up to 30% of the volumetric flow.

How it Works

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Ease of Installation and Commissioning

Installation Ease 
Multi-point wet calibration enables hassle-free installation and accurate flow measurement from start-up.

Space Saving Design 
The compact size of the complete sensor assembly ensures that the flow sensor can be easily installed even in tight spaces.

Comprehensive diagnostic functions
The comprehensive diagnostics functions feature an automatic air-bubble and water presence detection.


Accurate Results Without Drift

The development of an inline flow sensor that uses ultrasonic transit-time technology to automatically measure and compensate for glycol concentration is a tremendous advance in thermal energy measurement. A single ‘fit and forget’ flow sensor is all that is necessary to compensate for the variable and changing viscosities as well as heat capacities of heat transfer fluids comprising up to 60 percent glycol. With no moving parts, the sensor is extremely robust and requires no calibration, providing certainty that the measured flow is correct. This makes it ideal for accurate, repeatable measurements, improving the control and efficiency of HVAC systems.

Solution Leadership

"As the leading global manufacturer of actuators, valves, and sensors, we understand our customers’ needs and challenges. Belimo delivers more than just products. We provide quality solutions that increase energy efficiency and reduce installation cost with the fastest delivery times in the industry.
The portfolio expansion of an ultrasonic flow sensor featuring patented glycol compensation technology is a true testament of our ongoing commitment to innovation."

Reto Raimann, Global Business Development Manager for Belimo Sensor 

Additional Resources

Visit the regional website for more information