Saturday, February 10, 2018

Thermal Mass Flow Meter Targeted at HVAC Applications

flow averaging tube sensor for thermal mass flow measurement in air
The Flow Averaging Tube sensor assembly delivers an
improved representation of duct air flow.
Image courtesy Eldridge Products, Inc.
Heating, Ventilating and Air Conditioning (HVAC) is a process control application, similar in many respects to industrial production processes. Heat is transferred, moisture is controlled; air is moved; steam is generated. All of these operations involve measurements of temperature, moisture, flow, pressure, and more. Instrumentation is applied to HVAC systems of all sizes to monitor and regulate operation, with two essential goals: efficiency of operation and maintenance of desired space conditions.

A common measurement is air flow rate in a duct. The mass flow rate of air is an essential element in calculating the amount of heat or cooling delivered from supply equipment. There are other instances where highly accurate mass air flow measurements can contribute to the effective operation of an HVAC system.

Thermal mass flow measurement technology has been used in industrial process measurement and control applications for many years. The basic operation involves measuring flow in relation to its heat dissipating effect on a temperature sensor. Higher mass flow produces a higher rate of heat transfer. The technology is simple and self-contained within an instrument sensing tube or probe.

Thermal mass flow measurement instruments are popular for several reasons. They have no moving parts; present little obstruction to the fluid flow path; are accurate over a wide range of flow; measure mass flow rather than volume; measure flow in large or small piping systems; and do not need temperature or pressure compensation. While most thermal flow meters are used to measure flowing gas, they can also be applied to measure liquids.

Thermal mass flow meters are cost effective and accurate making them an excellent choice for HVAC air flow applications.

Eldridge Products employs a patented Flow Averaging Tube with their thermal mass flow transmitter to deliver accurate and reliable mass air flow measurements in ducts where flow conditions may not be ideal. The setup is available in a range of sizes and variants to suit almost any scale and complexity in HVAC application. The transmitter provides a common industrial signal corresponding to mass flow rate, as well as a temperature signal.

Share your HVAC measurement and control challenges with application specialists, leveraging your own knowledge and experience with their product application expertise to develop an effective solution.