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Air Balancing HVAC Systems

Methods of Air Balancing

Air balancing a distribution system is needed to properly direct the air flow in order to optimize the system’s design. Flow rates are tested, adjusted, and balanced as cubic feet per minute (CFM) or cubic meters per hour (m3/h). There are two traditional methods for balancing airflow at the terminals. The first is sequential balancing, which involves setting the zone and branch dampers in sequence. However, the most common method of air balancing is called proportional balancing.

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Non-Dispersive Infrared, NDIR, Carbon Dioxide Sensors

Non-Dispersive Infrared, NDIR, CO2 Sensors

Dwyer offers several carbon dioxide measuring products that use non-dispersive infrared sensors as the sensing element. Carbon dioxide sensors are commonly used in building automation systems to monitor air quality.  The level of carbon dioxide is indirectly proportional to the amount of people in a space and can be used to adjust ventilation for the space.

 

There are two basic types of gas sensing technologies: chemical reaction and infrared spectroscopic. Most chemical reaction sensors are electrochemical sensors, which are not as reliable as they can interact with multiple gases and wear from interaction with the gas. Continue reading “Non-Dispersive Infrared, NDIR, Carbon Dioxide Sensors”

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Balancing a HVAC System with Multiple Diffuser Types

The Problem

  • Standard air flow hoods do not correct for diffuser type when balancing a system.
  • Proportional balancing is extremely difficult when a mixture of diffusers are present, due to the inaccuracy of standard hoods on slot diffusers.
  • Below is a sample of diffusers tested on Dwyer’s Precision Air Calibration Station (Figure A) with a standard air flow hood followed by the Dwyer SMART Air Hood™ Balancing Instrument (Series SAH).

Figure A: Precision Air Hood Calibration Station
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