Accurate Airflow Measurement Provides the Foundation for HVAC Energy Efficiency | Averaging Airflow Measuring Tube Applications
Accurate Airflow Measurement Provides the Foundation for HVAC Energy Efficiency | Averaging Airflow Measuring Tube Applications
Accurate Airflow Measurement Provides the Foundation for HVAC Energy Efficiency | Averaging Airflow Measuring Tube Applications
In semiconductor cleanrooms, AI data centers, smart buildings, and other facilities, HVAC and ventilation systems often operate continuously for extended periods. For facility and equipment maintenance teams, insufficient airflow may affect cleanroom pressure differentials, process environments, equipment cooling, or exhaust performance. On the other hand, maintaining airflow above actual demand for long periods may result in unnecessary energy consumption by fans and air-conditioning systems.
Therefore, before adjusting an HVAC system, the first question should not be, “How much further can we reduce fan speed?” Instead, it should be:
What is the actual airflow inside the duct, and does the measured value truly represent the overall duct airflow?
Only by establishing reliable airflow measurement data can airflow balancing, equipment adjustment, and energy management be carried out on a meaningful basis.
From Single-Point Air Velocity to More Representative Average Airflow
Airflow inside large HVAC ducts is rarely distributed evenly. Elbows, dampers, transitions, branches, fan outlets, and other duct structures can create different velocity profiles across the duct cross-section.
When measurement is taken at only one point inside the duct, the result represents only the local air velocity at that position and may not accurately reflect the average condition across the entire duct. If the measurement point happens to be in a locally high- or low-velocity region, the result may also be significantly affected by the airflow profile and installation position.
The eyc-tech AFMC HVAC Average Flow Measuring Tube and AFMP Average Flow Measuring Tube (Pitot tube) both operate on the averaging Pitot tube principle. Multiple pressure sensing ports are distributed along the probe to collect pressure information from different positions across the duct. Combined with differential pressure measurement, this provides a more representative indication of average air velocity and airflow.
Compared with single-point measurement, multi-point averaging helps reduce the influence of localized airflow conditions, allowing the measured data to better represent the overall airflow condition across the duct cross-section.
The real value of this approach is not simply more stable data. It provides facility engineers with more meaningful measurement information when performing airflow balancing, adjusting VFD-controlled fans, or verifying equipment performance.
Similar Averaging Airflow Measurement Principles, Different Applications for AFMC and AFMP
AFMC and AFMP use similar averaging Pitot tube measurement principles, but their different materials make them suitable for different duct environments and operating conditions.
AFMC is constructed from aluminum alloy, providing the advantages of low weight and convenient installation. It is mainly designed for general HVAC and indoor air-conditioning environments, including MAU / AHU main ducts, semiconductor cleanroom HVAC systems, AI data center CRAH / AHU supply and return air systems, as well as ventilation ducts in commercial buildings and industrial facilities.
AFMC features a multi-port design that averages the differential pressure obtained from multiple measurement positions, helping provide more stable and representative airflow measurement. Its low-pressure-loss design also supports the measurement of small differential pressure changes. For applications requiring lower air velocity measurement, AFMC can be paired with the eyc-tech PMM330 Differential Pressure Transmitter, supporting low air velocity measurement requirements down to approximately 1 m/s.
Some industrial environments, however, may involve higher temperatures, higher pressures, exhaust air, or mildly corrosive conditions. In such applications, the requirements for probe material and long-term durability differ from those of general HVAC systems.
AFMP is constructed from stainless steel, extending the multi-port averaging Pitot tube measurement concept to more demanding industrial applications, such as process exhaust, exhaust gas removal, high-temperature ducts, and other ventilation systems requiring greater environmental durability.
AFMC and AFMP therefore allow users to select a measurement solution according to actual site conditions. AFMC is generally suitable for HVAC systems, semiconductor cleanrooms, and AI data centers, while AFMP can be considered for more demanding industrial environments.
Extending Average Airflow Measurement to Local Display and System Control
AFMC / AFMP obtain average differential pressure from the duct. In a complete airflow measurement system, a differential pressure transmitter is also required to convert the measured pressure signal into data that can be used for monitoring and control.
For general HVAC and low-air-velocity applications, the system can be paired with the PMM330 Differential Pressure Transmitter. Where a wider differential pressure measurement range is required, the PMD330 Differential Pressure Transmitter can be selected according to the operating conditions.
Measurement signals can then be integrated into existing PLC, DDC, BMS, or SCADA systems to continuously track airflow changes and provide a data basis for VFD fan adjustment, airflow balancing, and equipment operation management.
If operators also need to view airflow conditions directly at the equipment location in addition to central monitoring, the system can be further combined with the eyc-tech DPM04 Flow Totalizer.
The DPM04 displays both instantaneous and accumulated flow values at the equipment site, allowing maintenance personnel to understand current operating conditions more directly. This makes airflow information available not only in the central control room, but also directly at the equipment.
A complete system can therefore begin with AFMC / AFMP for duct measurement, combine PMM330 / PMD330 for differential pressure measurement and airflow signal processing, add DPM04 for local display when required, and finally integrate the data into an existing central control system.
By establishing complete architecture from measurement and display to centralized monitoring, airflow management that once relied heavily on experience can gradually shift toward decisions based on actual measured data.
Semiconductor Cleanrooms: Managing Airflow While Maintaining Environmental Stability and System Efficiency
MAU / AHU systems in semiconductor cleanrooms must continuously maintain cleanliness, pressure differentials, temperature, humidity, and process environmental conditions. Therefore, airflow should not simply be managed according to the assumption that “more airflow is always safer.”
Without actual airflow data, facility teams may find it difficult to determine whether the current airflow supply is appropriate or to confirm whether the required environmental conditions are still maintained after adjusting fans or dampers.
AFMC can be installed in main HVAC ducts such as MAU / AHU systems. Its multi-port averaging design provides more representative airflow information, enabling facility teams to continuously verify supply airflow conditions and use the data as a basis for airflow balancing, equipment adjustment, and operational management.
For semiconductor environments, the purpose of AFMC is not simply to “reduce airflow.” Instead, it helps operators understand the actual airflow more clearly while continuing to meet process and environmental requirements.
AI Data Centers: Liquid Cooling Is Expanding, but Airflow Management Remains Important
As GPU computing power and rack heat density continue to increase, AI data centers are increasingly adopting Direct-to-Chip liquid cooling and Coolant Distribution Units (CDUs). However, this does not mean that air-cooling systems disappear entirely.
Some non-liquid-cooled components, equipment, and room environments may still rely on CRAH / AHU systems for supplemental cooling. Actual airflow through main supply and return air systems therefore remain an important operational parameter.
AFMC can be installed in CRAH / AHU main supply ducts, return ducts, and other HVAC ducts with fixed cross-sections, helping operations teams understand actual airflow delivery.
With continuous airflow measurement, facility managers can make equipment adjustments based on measured data rather than relying solely on fan settings or operating experience. While ensuring that equipment cooling requirements are met, the data can also help identify opportunities to further optimize cooling system operation.
Industrial Ventilation and Exhaust: AFMP for More Demanding Operating Conditions
In addition to semiconductor facilities and data centers, manufacturing, exhaust, and process systems also require reliable airflow measurement.
Compared with general HVAC environments, industrial sites may involve higher temperatures, exhaust air, mildly corrosive conditions, or higher operating pressures. In these applications, the measuring tube must not only provide stable average airflow information but also use materials suitable for long-term operation under the actual environmental conditions.
AFMP uses stainless steel construction and applies the same multi-port averaging measurement concept to more demanding industrial environments. This allows average airflow measurement to extend beyond indoor HVAC systems into process exhaust, exhaust gas removal, and other industrial ventilation applications.
Users can therefore select different products according to actual site conditions—from general HVAC ducts to industrial ventilation systems—rather than applying the same material and product design to every measurement environment.
When Measurement Data Drives Decisions, Calibration Traceability Matters
When airflow data is used only as a basic on-site reference, users may not pay much attention to the calibration capability behind the measured value.
However, once the data is used for airflow balancing, VFD control, equipment performance verification, energy improvement projects, or long-term trend comparison, measurement stability, reliability, and traceability become critical to subsequent decisions.
For this reason, the value provided by eyc-tech AFMC / AFMP extends beyond the measurement structure of the products themselves and includes comprehensive in-house inspection and calibration capabilities.
Products can be inspected and calibrated using the company's in-house air velocity and airflow calibration equipment. Before shipment, product response and stability under different airflow conditions can be verified, providing a comprehensive quality assurance foundation before the products are installed in actual systems.
In addition to in-house factory inspection and calibration capabilities, YUDEN-TECH CO., LTD. has also established a national-level calibration laboratory accredited in accordance with TAF ISO/IEC 17025.
For customers with higher quality management or measurement traceability requirements, professional calibration can be performed through the company's ISO/IEC 17025 calibration laboratory according to actual requirements, establishing a complete and traceable calibration basis for the measurement results.
This capability is particularly important for semiconductor manufacturing, high-tech industries, data centers, and system integrators. When airflow data is used as a basis for equipment control or system optimization, customers need more than simply “a measured number.” They need confidence that the data comes from a measurement system supported by comprehensive inspection, calibration, and traceability capabilities.
AFMC / AFMP address the challenge of obtaining more representative airflow measurements, while factory calibration and ISO/IEC 17025 calibration capabilities further ensure that the resulting data can be trusted.
Select the Right Measurement Solution for the Environment — and Measure Actual Airflow First
From AFMC for general HVAC systems, semiconductor cleanrooms, and AI data centers, to AFMP for higher-temperature, mildly corrosive, or more demanding industrial conditions, the system can be further combined with PMM330 / PMD330 differential pressure transmitters, DPM04 local display, and YUDEN-TECH's factory calibration and ISO/IEC 17025 calibration capabilities.
In this way, eyc-tech extends airflow measurement from individual products into a comprehensive measurement and management solution.
Accurate measurement, clear visualization, system integration, and measurement traceability are what enable airflow data to become a meaningful basis for equipment management and system optimization.
Features : Multi-hole averaging design for stable HVAC duct measurement down to 1 m/s with the PMM330.
Operating pressure : 1 bar
Operating temperature : 0 ... 80°C
Length : 100 ... 1000 mm
Features : Multi-point averaging. Suitable for large pipes. Resistant to high temperature and corrosion.
Operating pressure : Standard type : Max. 10 bar / High-temp. type : Max. 4 bar
Operating temperature : Standard type : Max. 200°C / High-temp. type : Max. 600°C
Length : 2" ... 40"(50 ... 1000 mm)
Feature : Suitable for HVAC and light industry
Measuring element : Hot-wire type diff. pressure sensor, flow-through
Measuring range : ±50 ... ±1500 Pa
Output : 4 ... 20 mA / 0 ... 10 V / RS-485
Accuracy : ±1.0% F.S. ±4% M.V
IP rating : IP65
Features : Suitable for hospital and clean room; Wide measuring range
Measuring element : Piezoresistive diff. pressure sensor, no flow-through
Measuring range：±50 ... ±10000 pa
Output : 4 ... 20 mA / 0 ... 10 V / RS-485
Accuracy : ±1.0% F.S. ±5% M.V
IP rating : IP65
Features : 2" LCD display for air/liquid flow transmitters with RS-485 and relay output, for both instantaneous and cumulative flow monitoring
Display readout : Instantaneous flow : 5-digit / Cumulative flow : 8-digit
Input : Current / Voltage / Frequency / Pulse
Output : Current / Voltage / Relay / RS-485
Accuracy : ±0.1% F.S. ±1 digit
IP rating : IP65 (Front panel)