What temperature difference is used in calculating CFM from sensible load and supply air temperature?

The correct choice of 17 degrees F relates to how the temperature difference influences the calculation of CFM (Cubic Feet per Minute) from the sensible load and supply air temperature. In HVAC applications, the sensible heat formula typically involves the temperature difference between the return air and the supply air to determine the amount of cooling or heating needed to maintain comfort.

The 17 degrees F difference is derived based on standard design conditions found in HVAC calculations, particularly when determining air flow rates for cooling systems. This temperature differential allows HVAC professionals to accurately estimate how many CFM are necessary to meet the desired sensible load.

Understanding that this specified difference of 17 degrees F is a recognized standard aids in ensuring that systems are optimized for efficiency and comfort. It plays a crucial role in formulas like the sensible cooling load formula:

[ CFM = \frac{Sensible Load (BTU/hr)}{1.08 \times \Delta T} ]

where ΔT (the temperature difference) is crucial for obtaining the correct CFM. By applying this established guideline, technicians can confidently design, size, and adjust HVAC installations for optimal performance.