Duct Sizing - Pressure drop considerations on outlets

Duncan Brown — Thu, 29 Sep 2016 10:57:46 GMT

Current Revision posted to Hevacomp Wiki by Duncan Brown on 9/29/2016 10:57:46 AM

	Product(s):	Hevacomp Netsys
	Version(s):	V8i (N/A)
	Environment:	N/A
	Area:	N/A
	Subarea:	N/A

Overview

While the Netsys program does not consider any additional drop pressure for grilles, etc, the calculation does consider a k value of 1 to account for discharge pressure. This accounts for air coming from a large space to a small space (for e.g. room > duct (supply) or duct > outside (extract).

Method

Velocity Pressure is calculated as follows:

VP = ½ ρV²

Where:

VP = Velocity Pressure
ρ (Rho) = Density of air*
V = Calculated velocity in duct section

*approximately 1.2kg/m³, but adjusted for the temperature provided in the System Marker

Consider we have a velocity of 10m/s in a duct section, and an air density of 1.2kg/m³

VP = 0.5 x 1.2 x 10² = 60pa

Tags: pressure drop, Hevacomp Mechanical Designer, discharge pressure, netsys, velocity pressure, ducts ductwork

Duct Sizing - Pressure drop considerations on outlets

Duncan Brown — Thu, 24 Mar 2016 15:00:13 GMT

Revision 1 posted to Hevacomp Wiki by Duncan Brown on 3/24/2016 3:00:13 PM


	Applies To

	Product(s):	Hevacomp Mechanical Designer
	Version(s):	V8i
	Environment:	N/A
	Area:	N/A
	Subarea:	N/A
	Original Author:	Bentley Technical Support Group

Overview

While the Netsys program does not consider any addition pressure for grilles, etc, the calculation does consider a k value of 1 to account for discharge pressure. This accounts for air coming from a large space to a small space (for e.g. room > duct (supply) or duct > outside (extract).

Method

Velocity Pressure is calculated as follows:

VP = ½ ρV²

Where:

VP = Velocity Pressure
ρ (Rho) = Density of air*
V = Calculated velocity in duct section

*approximately 1.2kg/m³, but adjusted for the temperature provided in the System Marker

Consider we have a velocity of 10m/s in a duct section, and an air density of 1.2kg/m³

VP = 0.5 x 1.2 x 10² = 60pa

External links

Bentley homepage

Bentley LEARN Server

Tags: Ducts, pressure drop, discharge pressure, netsys, velocity pressure

Duct Sizing - Pressure drop considerations on outlets

Duct Sizing - Pressure drop considerations on outlets

Overview

Method

Duct Sizing - Pressure drop considerations on outlets

Overview

Method

See Also

External links