Return Air Duct Design

Duct fittings and terminal units.

Return air duct design.

This duct does an excellent job of absorbing sound from the blower. Not providing enough returns is a common ductwork design flaw that leads to comfort complaints. Just to note that we will use a cp of 1 026 kj kg k as standard and the delta t should be less than 10 c so we ll use 8 c. The problem with bedrooms occurs in houses where the hvac design did not include return vents in each bedroom.

To maintain balanced air pressure and air movement your duct system needs return vents for air in the room to be pulled back into the hvac system. The furnace or air handler ahu in the drawing below pulls air through the return ducts conditions that air and then sends it through the supply ducts back into the house. The unico return duct upc 04 xxxx is an acoustical flex duct 10 ft 3 m long. The third example shows a return air base beneath the air handler furnace.

9 1 distributed return. 8 7 rules of duct design acca manual d residential duct systems 9 0. Rounded throats on ells drastically improve airflow especially a rounded inside throat. 10 3 fire and smoke dampers.

Square ells return or supply are a bad idea. Duct sizing duct calculation duct design energy efficient ductwork design. The furnace or air handler is probably on the other side of the wall. A person can be forgiven for not knowing much about their home s air duct system.

The return air ducts in an hvac system are especially liable to get taken for granted even though their part in heating and cooling your home is just as essential as supply ducts. 9 3 pressure balancing. If you need a longer duct add either another sec tion of the unico return duct or a length of plastic core flex duct between the unit and the unico return duct. 10 2 volume control dampers.

6 tips for good ductwork design. And δt being the temperature difference between the designed air temperature and the design return temperature. They should be on interior walls across the room from the supply ducts that should be washing exterior walls with conditioned air the red arrow points to a large wall mounted return air vent. Each one in a system can add as much as 80 to the tel.

This is the best configuration and mandatory if the unit has a 5 ton blower. 10 4 diffusers grilles registers. An hvac return air duct should be in every room except a bathroom and kitchen. 10 1 duct fittings and transitions.