In a dual-duct system, after mixing, air is delivered at a near constant which parameter?

In a dual-duct system, after mixing, air is delivered at a near constant which parameter?

• A. Volume
• B. Pressure
• C. Mass
• D. Density

Answer: (A)

In a dual-duct mixing system, two air streams (hot and cold) are blended to achieve the desired space temperature, while the total amount of air delivered is kept essentially constant. The mixing ratio changes to set temperature, but the overall volume of supply air is held steady to satisfy ventilation requirements. Temperature varies with how much hot versus cold air is mixed, not the total flow. Pressure and density can change with conditions, and mass flow would vary with density even if volume stayed the same, but the system’s main control goal is a near-constant volume of air delivered.

In a dual-duct mixing system, two air streams (hot and cold) are blended to achieve the desired space temperature, while the total amount of air delivered is kept essentially constant. The mixing ratio changes to set temperature, but the overall volume of supply air is held steady to satisfy ventilation requirements. Temperature varies with how much hot versus cold air is mixed, not the total flow. Pressure and density can change with conditions, and mass flow would vary with density even if volume stayed the same, but the system’s main control goal is a near-constant volume of air delivered.