CFM = Sensible Heat Load (Btu/hr) / (1.08 * ΔT)
Below is a breakdown of the core HVAC calculations you can perform effectively in Excel, along with the logic to build them. Excel excels at handling the repetitive yet formulaic nature of heat gain calculations. The most common manual method is the CLTD/CLF/SCL (Cooling Load Temperature Difference / Cooling Load Factor / Solar Cooling Load) method. hvac design calculations excel
Store a friction loss vs. CFM vs. diameter table. Use INDEX/MATCH or linear interpolation to find the nearest duct diameter for a given CFM at your target friction rate. CFM = Sensible Heat Load (Btu/hr) / (1