Air Conditioning Duct Sizing Methods

There are three methods used for most modern duct sizing.

Air conditioning duct sizing methods.

1 and the charts below. Duct sizing equal pressure method on the chart we start by drawing a line from 0 65 pa m all the way up and then draw a line across from our required volume flow rate in this case for section c we need 0 21m3 s. There are three different ways to calculate duct size known as the velocity method constant pressure loss method and static pressure recovery method. The first is the velocity method.

These are all very complex methods and usually should be conducted by a professional. Methods used for sizing. Select suitable velocities for main and branch ducts from the table below. The first method of hvac duct sizing is what is called a manual j.

This method which is usually performed by a professional contractor involves using a computer program and the technical specifications of the heating or cooling unit in question to determine the proper hvac duct sizing requirements for a building. The velocity method takes into account the speed at which air flows through the ducts based on their general size. Find the sizes of main and branch ducts from the air flow rates and the velocities by using eq.