1. Heating Ventilating and Air Conditioning
Civil Engineering and Architecture
Unit 3 – Lesson 3.3 – Services and Utilities
Heating, Ventilating, and Air Conditioning
HVAC
Ardrey Kell High School
Charlotte, NC
Revised May 11, 2017
Project Lead The Way, Inc.
Copyright 2010

2. Heating Ventilating and Air Conditioning
Civil Engineering and Architecture
Unit 3 – Lesson 3.3 – Services and Utilities
TABLE OF CONTENTS
Types of HVAC Systems
Central Forced Air System: Air Handling Unit
Hot Water System
Radiant Heat
Heat Pumps
HVAC Plans
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Copyright 2010

3. Central Forced Air System
Heating Ventilating and Air Conditioning
Central Forced Air System
Civil Engineering and Architecture
Unit 3 – Lesson 3.3 – Services and Utilities
Most Common type of HVAC System
Central forced air systems circulate air through or around heating and cooling devices via a system of ducts. This system of ductwork is known as a plenum.
A fan in the system is used to force air into the ducts.
Supply ducts transport conditioned air into the building through supply registers, and the air is routed back to the heating/cooling device through return ducts.
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4. Air Handling Unit (AHU)
Heating Ventilating and Air Conditioning
Civil Engineering and Architecture
Unit 3 – Lesson 3.3 – Services and Utilities
Air Handling Unit (AHU)
An AHU is a device used to condition and circulate air as part of an HVAC system.
It usually consists of a large metal box containing a blower, heating or cooling elements, filter, and sound attenuators.
The AHU connects to ductwork that distributes the conditioned air through the building and returns it to the AHU for re-conditioning.
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Copyright 2010

5. Air Handling Unit (AHU)
Heating Ventilating and Air Conditioning
Civil Engineering and Architecture
Unit 3 – Lesson 3.3 – Services and Utilities
Air Handling Unit (AHU)
AHU’s are used to supply both heating and cooling
A furnace generates heat
Fuel oil or natural gas
Electric heating elements
Heat pump
A refrigeration system absorbs heat
Air conditioner
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6. Air Handling Unit (AHU)
Heating Ventilating and Air Conditioning
Civil Engineering and Architecture
Unit 3 – Lesson 3.3 – Services and Utilities
Air Handling Unit (AHU)
Smaller air handlers often contain a fuel-burning heater, or a refrigeration evaporator placed directly in the air stream passing through it.
Large commercial air handling units contain coils that circulate water
A Boiler provides hot water or steam for heat.
A Chiller provides chilled water for large Air Conditioners.
The picture on the left shows a boiler and piping in an HVAC system.
The picture on the right shows a roof top chiller.
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Copyright 2010

7. Air Handling Unit (AHU)
Heating Ventilating and Air Conditioning
Air Handling Unit (AHU)
Civil Engineering and Architecture
Unit 3 – Lesson 3.3 – Services and Utilities
1. Supply ducts provide conditioned air from the HVAC unit to the rooms of a building.
2. Flexible connections are used to join the separate sections of the AHU together. Flexible connections allow for ease of installation.
3. The fan compartment contains a “squirrel cage” fan that pushes air through the AHU
4. The heating and cooling coils are the location where the heat is either added to or removed from the air passing through the system.
Typical AHU components:
1. Supply duct 2. Fan compartment 3. Flexible connection 4. Heating and/or cooling coil 5. Filter compartment 6. Return and fresh air duct
5. The Filtration compartment contains filters that remove contaminants from the air passing through the AHU.
6. The Fresh Air Return is where air is taken into the HVAC system to be conditioned (Heated or cooled)
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8. HVAC Returns Residential HVAC Return
The return air entry is where air from the building is taken into the HVAC unit.
Filters are placed in the return lines to prevent dust and allergens from entering the system.
These filters should be changed monthly.
Residential HVAC Return
Common Air Filter

9. HVAC Supply Registers Floor Mounted Register Wall Mounted Register
The supply register is the location in an HVAC system where the conditioned air is distributed into the space being cooled or heated.
There are more supply registers than returns in most systems, though supply registers are typically smaller.
Floor Mounted Register
Wall Mounted Register

10. HVAC Add-On’s Dehumidifier
Dehumidifiers are added to HVAC systems to reduce the moisture content of the air returned to the conditioned space.
Most dehumidifiers are attached to the building’s plumbing system in order to drain water absorbed from the air passing through the system.
Dehumidifier

11. HVAC Add-On’s UV Air Purifier
UV (Ultraviolet light) air purifiers are often used in buildings such as hospitals, or in structures where allergies and the spread of germs could be a problem.
UV air purifiers are used to eliminate germs and odors in the air as the air passes through the cleaner.
UV Air Purifier

12. Heating Ventilating and Air Conditioning
Civil Engineering and Architecture
Unit 3 – Lesson 3.3 – Services and Utilities
Hot Water System
In a Hot Water HVAC system, water is heated in a boiler and circulated through pipes to radiators throughout the building.
Requires plumbing rather than ductwork. Ductwork is used to carry air, plumbing carries liquids.
The picture shows a home radiator. Despite the name, a radiator actually works through convection.
Cool air is heated by the hot radiator, which causes the air to expand and rise. This process draws cooler air up from the floor.
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13. Heating Ventilating and Air Conditioning
Civil Engineering and Architecture
Unit 3 – Lesson 3.3 – Services and Utilities
Radiant Heat
Radiant heat systems supply heat directly to a floor, wall, or ceiling.
Hot water pipes, or electric heating elements are run through building components such as a wall, or tile floor. These elements transfer heat to the wall or floor tiles, which in turn radiate the heat to the living area of the room.
This image shows the installation of electric heating elements in a floor. The base is a rubber mat with electrical heating elements contained within. The brown material is the adhesive being applied that will hold down the floor tiles.
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Copyright 2010

14. Heating Ventilating and Air Conditioning
Civil Engineering and Architecture
Unit 3 – Lesson 3.3 – Services and Utilities
Heat Pump (HP)
A heat pump is a machine or device that moves heat from one location (the source) to another location (the mechanical work)
Heat pumps can produce heating or cooling by reversing the direction of heat flow
Heat pumps can be used to supply a:
Forced Air System
Hot Water System
Radiant Heat System
This picture shows a liquid-to-water heat pump which uses water to transfer heat. Liquid-to-air units that output forced air are also available.
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Copyright 2010

15. Heating Ventilating and Air Conditioning
Civil Engineering and Architecture
Unit 3 – Lesson 3.3 – Services and Utilities
Heat Pump (HP)
During cold weather, a heat pump extracts outside heat from the air, and transfers it to the inside of the building. During warmer weather, heat pumps reverse operation and perform like an air conditioner, removing heat from the building.
The significant advantage a heat pump has over other type units is that it moves heat instead of generating heat. This provides much more energy efficiency.
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Copyright 2010

16. Heating Ventilating and Air Conditioning
Civil Engineering and Architecture
Unit 3 – Lesson 3.3 – Services and Utilities
HVAC Plans
HVAC plans show the size and location of the equipment, ductwork, and components of the HVAC system. Often the plans include notes, schedules, and specifications. This is a partial HVAC drawing.
Image Courtesy Novus Architects
Project Lead The Way, Inc.
Copyright 2010

17. HVAC (Mechanical) Plans
Heating Ventilating and Air Conditioning
HVAC (Mechanical) Plans
Civil Engineering and Architecture
Unit 3 – Lesson 3.3 – Services and Utilities
Here the air handling units (AHU) have been shaded red, the supply ducts have been shaded green, and the return ducts have been shaded blue. Notice that the air flows are also noted in cubic feet per minute (CFM). All of the tags refer to specific component descriptions found in schedules within the drawing set.
Image Courtesy Novus Architects
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Copyright 2010

18. Heating Ventilating and Air Conditioning
HVAC Mechanical Plans
Civil Engineering and Architecture
Unit 3 – Lesson 3.3 – Services and Utilities
Image Courtesy Novus Architects
In addition to supply and return ducts, codes require that some rooms be vented directly to the outside. These exhaust ducts are shaded yellow in this image.
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Copyright 2010

19. Heating Ventilating and Air Conditioning
Civil Engineering and Architecture
Unit 3 – Lesson 3.3 – Services and Utilities
Image Sources
en.wikimedia.org. Images retrieved Dec. 8, 2009.
Novus Architecture (formerly SGM Architects), Mt. Pleasant, SC
Images retrieved Dec. 8, 2009.
Project Lead The Way, Inc.
Copyright 2010

20. Heating Ventilating and Air Conditioning
Civil Engineering and Architecture
Unit 3 – Lesson 3.3 – Services and Utilities
End of Presentation
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Copyright 2010