Design of Ducts for Central Air Conditioning systems

In air conditioning systems:

• use air as the fluid,

• it is essential to design the Air Handling Unit (AHU) & Duct Network properly

The primary function of an AHU & Ducts is to transmit processed air from the air conditioning plant to the conditioned space and distribute it properly within the conditioned space.

A typical AHU consists of:

- A duct system that includes a supply air duct, return air duct, cooling and/or heating coils, humidifiers/dehumidifiers, air filters and

   dampers

- An air distribution system comprising various types of outlets for supply air and inlets for return air

- Supply and return air fans which provide the necessary energy to move the air throughout the system

This course covers the following & is essential for HVAC engineers and Mechanical engineering students:

1. Describe an Air Handling Unit (AHU) and its functions

2. Discuss the need for studying transmission aspects of air in air conditioning

3.General rules for duct design

4. Classification of duct systems

5.Discuss airflow through air conditioning ducts, Bernoulli and modified Bernoulli equations, Static, dynamic, datum and total head, Fan Total Pressure (FTP) and power input to fan

6. Discuss estimation of pressure loss through air conditioning ducts

5. Estimation of frictional pressure drop of circular and rectangular ducts using friction charts and equations.

**Important requirements of an air conditioning duct**

Classification of duct systems

Commonly used duct design methods

Principle of velocity method

Principle of equal friction method

Principle of static regain method

Performance of duct systems

System balancing and optimization

Introduction to fans and fan laws