VAV Box Calculator

Input Parameters

Imperial (°F, BTU, ft)SI (°C, kW, m)

Max Airflow (CFM)

Min Airflow (CFM)

Cooling Load (BTU/hr)

Supply Temperature (°F)

Room Temperature (°F)

1,111

Required Airflow CFM

Turndown Ratio

Reheat Required BTU/hr

Required Airflow1,111 CFM(100%)

Turndown Ratio5 (20%)

Reheat0 BTU/hr(0%)

Formula:

\Delta T = T_{room} - T_{supply}

Calculation:

\Delta T = 75 - 55

Result:

20.0 \text{ °F}

Formula:

CFM = \frac{Q_{BTU/hr}}{1.08 \times \Delta T}

Calculation:

CFM = \frac{24000.00}{1.08 \times 20.0}

Result:

1111.11 \text{ CFM}

Formula:

Turndown = \frac{CFM_{max}}{CFM_{min}}

Calculation:

Turndown = \frac{1000.00}{200.00}

Result:

5.00 \text{ }