Print this page HVAC Air Handling Unit Design Considerations
A. Bhatia, B.E.
Course Outline
A properly designed HVAC system performs three basic functions: 1) Controls temperature and humidity to provide thermal comfort, 2) Distributes adequate amounts of outdoor air to meet ventilation needs and 3) Isolates and removes odors and pollutants through pressure control, filtration, and exhaust fans. An air handling unit often abbreviated as AHU is a very important component of central-air-conditioning system, that is responsible for drawing return air from the indoor spaces, mixing it with outdoor air and processing that air to the appropriate conditions to be supplied to the building spaces.
This 4-hr course outlines the primary functions of various sub-items of air handling units and discusses the key design considerations for estimating the capacity and airflow rate.
The course includes
a multiple-choice quiz at the end, which is designed to enhance the understanding
of the course materials.
At the conclusion of this course, the reader will be able to answer:
- What is function of Air handling unit and what factors affect its sizing?
- How are air-conditioning processes depicted on the psychrometric chart?
- What is difference between room sensible and grand sensible heat factor?
- How is airflow rate and the cooling coil load determined?
- What are the five basic AHU arrangements?
- What are the different types and applications of the fans used in air handling applications?
- What are the different types of cooling and heating coils?
- What are the different types and applications of the filters used in air handling applications?
- What are the different types of humidifiers and dehumidifiers?
- What are the different types of control valves and their application?
- How are the air handling unit controlled and the sequence of operation for critical facility? and
- What are the
energy conservation features in designing air handling systems?
Intended Audience
This course is aimed at Mechanical and HVAC engineers, Architects, Building designers, Energy Auditors, Facility managers, Property & Estate managers, Operational & Maintenance Personnel, Sales & Marketing personnel, and General Audience.
Course Introduction
The term 'air handling
system' refers to equipment that provides heating, cooling, filtered outdoor
air, and humidity control in a building. It utilizes various types of equipment
such as fan/s (blower/s) and motor, cooling & heating coils, heater compartment,
sound attenuators, filter section, mixing box, or combination mixing box filter
section with dampers all arranged in a specific order. Within each basic component
there are different types and styles, each with their own operating characteristics
and efficiency, method and materials of construction, and cost, all of which
greatly affect the initial design and resulting operating economics of the system.
Course
Content
The course content is in a PDF file HVAC Air Handling Unit Design Considerations. You need to open or download this document to study this course.
Course SummaryThe air handling unit is the equipment where air is conditioned to an acceptable level for distribution within the building. An air handling unit is composed of several components and subsystems, defined as follows:
- Mixing Box: The mixing box is the location where return air and outdoor air are mixed to satisfy outdoor air requirements set forth in the ASHRAE standards.
- Filter: The filter removes particulates from the air. The amount and size of particulates removed depends on the rating of the filter.
- Cooling Coil: The cooling coil cools the air to the desired temperature. In addition to cooling the air, moisture is removed from the air in a dehumidification process based on the properties of air.
- Heating Coil: The heating coil can have a hot water or steam medium. The primary purpose of this coil is to heat the air to a required temperature.
- Humidifier: A humidifier adds moisture to the air in the heating mode, if required. Humidifiers are commonly served by a steam manifold.
- Fan: The fan pressurizes the air so it can travel through the ductwork to the space requiring the air.
- Ductwork: The
ductwork serves as a pathway for the transportation of the air from the air
handling unit to the space.
The modular packaged equipment offered by many of the major manufacturers is very standard. Designers can simply spec the performance requirements and pick and choose from a wide array of standard building blocks to assemble a unit that meets their specific project needs. HVAC designer must precisely estimate the capacity and airflow requirements, select the fan, coil and other auxiliaries and integrate these properly to the building control system.
Quiz
Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.
DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.
