The objective for this writing is to inform HVAC technicians and contractors about the limitations of testing equipment currently used for testing, adjusting, and balancing HVAC systems. The need for more accurate instruments is immediate as energy programs are moving toward net-zero energy building efficiencies.
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.
Dwyer Instruments offers many styles of Pitot tubes, which are a commonly used sensor for monitoring air velocity and flow rate in heating, ventilation, and air conditioning.
Pitot tubes are based on Bernoulli’s equation, which states an increase in the speed of a fluid occurs simultaneously with an increase in dynamic pressure and a decrease in static pressure. Pitot Tubes sense the dynamic pressure of the fluid flow at a particular point and were invented by French Engineer Henri Pitot in the early 18th century.