air ventilation

1. HVAC
Heating ventilation And Air Conditioning
(The Technology of Indoor & Vehicular Environmental Comfort.)
Goal of HVAC: Is to provide thermal Comfort &
Acceptable indoor air Quality.

2. Standards Of HAVC
SMACNA-Sheet Metal Air Conditioning National Association
(For Ducts…)
ASHRAE-American Society of Heating Refrigerating and Air-
Conditioning Engineers
ISHRAE-Indian Society of Heating Refrigerating and Air-
Conditioning Engineers

3. Systems In HVAC
.Duct
.VAV-Variable Air Volume
.CAV-Constant Air Volume
.AHU-Air Handling Unit
.Damper
.Chiller System
.Cooling Towers
.Fan Coil Unit/Flow Control Unit

4. AC’s
Ac’s are 4 types:
• Window Ac
• Split Ac (Gas Pipe (R1, R2, NH3(Ammonia (or)H3N), CO2(Carbon Dioxide)))
• Central Ac
• Packaged Ac: In this we have 2types, They are:
A) Water Cooled B) Air Cooled

5. Equivalent diameter for rectangular and circular ducts - air flows between 100 -
50000 cfm
Wt. of Ac:
• 1ton = 909 kg
= 400 CFM(Cubic Feet/ Min)
• 1 CFM = 0.47 LPS (Litre/Sec)
LPS- hrs
LPM-min
Example - Air Flow in Rectangular vs. Circular Duct
• 2000 cfm (0.94 m3/s) of air flows through a 10 x 12 inches rectangular duct.
• The friction loss 0.81 inches water gauge per 100 ft duct (approx.. 6.6 Pa/m).
• The velocity in the rectangular duct is
• v = (2000 cfm) / (((10 inches) (1/12 ft/inches) ((12 inches)(1/12 ft/inches)))
• = 2400 ft/min (12.2 m/s)
• The velocity in the the equivalent 12 inch circular duct according the table above is 2589 ft/min (13.2 m/s).

6. Ducts are passages used in heating, ventilation, and air
conditioning (HVAC) to deliver and remove air.

7. VAV supply a constant airflow at
a variable temperature

8. Air Handling Unit Is A Device used to regulate and
circulate air as part of a (HVAC) system.

9. AHU:Air Handiling Unit
Sizes of AHU: 3”x3”
6”x6”
8”x8”
10”x10”
12”x12”
14”x14”(2”x2” will be increased… )

11. .A damper is a mechanical device in a duct or chimney
.It regulates airflow.

12. DAMPERS AND DAMPER ACTUATORS
A damper is a device that controls the airflow in an air system or ventilating system by changing theangle of the
blades and therefore the area of its flow passage. In HVAC&R systems,dampers can bedivided into volume
control dampers and fire dampers. Fire dampers are covered in a later section.In this section,only volume
control dampers are discussed
Types of Volume Control Dampers
• Butterfly Dampers:A butterfly damper is a single-blade damper. A butterfly damper is made from
either a rectangular sheet mounted inside a rectangular duct or a round disk placed in a round duct
• Gate Dampers:A gate damper is a single-blade damper. It also may be rectangular or round. It slides
in and out of a slot in order to shut off or open up a flow passage
• Split Dampers:A split damper is also a single-blade damper. It is a piece of movable sheet metal that
is usually installed at the Y connection of a rectangular duct system

13. cooling tower is used to dispose of ("reject") unwanted heat
from a chiller

14. Types of Air Terminal
• Diffuser: It is always placed to the Ceiling only…
(Diffuser are usually placed 1’ (or) 2’ away from the Wall.)
• Grille :This are mostly placed to the Wall’s n also are also placed to
the Ceiling.
• Register: This are always placed to the Wall’s only…

15. A fan coil unit (FCU) is a device consisting of a heating
and/or cooling heat exchanger or 'coil' and fan

16. Types Of Ducts
1.Rectangular Duct
2.Round Duct
3.Oval Duct
4.Flexible Duct
3” Dia Oval
Duct
3” Dia
Round
duct
12”x12” Rectangular Duct

17. Types of Duct Systems:
• Supply Air Duct (SAD): The standard colour for Supply Air Duct is Blue
or Cyan.
• Return Air Duct (RAD): The standard colour for Return Air Duct is Pink
or Maganda.
• Exhaust Air Duct (EAD): The standard colour for Exhaust Air Duct is
Green or Lemon Green.

18. Supports: Ground Mounted Support

19. Placing of Supports: Starting one support we should place from 3’ and then we should place Either 6’ or 8’
but when ever the bends or the junction or turning points will come then we should place the support in 3’

20. Supports: Roof Mounted Supports
Hangers

21. Functioning of HVAC