Title: Unit 4 Outline
Course: HET 230 - Spring 2015 > Section: HET 230 - Spring 2015

Unit 4 Outline

Unit 4 Outline
Unit 4 Outline

Introduction:

Last week, we discussed pressure, airflow, dynamic loss, and common vocabulary terms.  A knowledgeable technician relies on a strong understanding of the dynamics of airflow through a duct system, insuring design integrity necessary to sustain an adequate static pressures and velocities for proper airflow and movement.

This week, you will learn about proper duct sizing, how to calculate pressure losses within a duct system and reinforce new vocabulary to help you gain a better understanding of these concepts.  In addition, you will be provided a PowerPoint a presentation, weekly study materials to help reaffirm these concepts. You will also participate in weekly discussions and complete all assignments and a content assessment quiz.  Proficient technicians know how to accurately estimate duct sizing using calculation tools.  It is important to understand these calculations as they apply to both round and square ducts, this is useful for planning and equipment sizing.  Learning these subjects will allow you to form a solid foundation for the next week’s session, Fan Safety & Types of Fans.

Objectives:

On completion of this week’s assignments, the student should be able to:

- estimate the proper duct sizing using the Equal Friction Loss Method
- understand the importance of Aspect Ratio while applying the Friction Loss Method
- recognize which duct shape has the least amount of friction loss
- demonstrate how to find the proper round duct size and velocity by plotting CFM and friction loss
- determine how to accurately convert round duct size to equivalent rectangular duct dimensions
- understand how to use Duct Calculators
- describe the other methods of duct sizing using the Extended Plenum and Static Regain methods
- calculate Pressure Losses in Ductwork
- discuss Total Pressure Losses and the components that create friction and dynamic loss, contributing to total pressure losses
- understand Fan System Effect
- recognize the key dimensions for calculating the loss coefficient
- determine pressure losses in fittings, straight duct, elbows, and transitions
- select the proper coefficients and where to find them

Key Vocabulary:

Aspect Ratio

Duct Calculator

Duct Branch

Dynamic Loss

Equal Friction Loss Calculator

Fan System Effect

Equal Friction Loss Method

Extended Plenum Method

Friction Loss

Plot Intersection

Portion of the Equal Friction Loss Chart