building services 2 slides

1. Mechanical Ventilation and
Air Conditioning

2. Introduction to Mechanical Ventilation
 Helps to provide fresh air in a building
• Circulating fresh air through ducts and fans
 Without it:
• moisture, odors and other pollutants can build up in a building
 Can be prevented by installing:
• fans directly in walls or windows
• In air ducts to supply air into or out of building

3. Introduction to Air Conditioning
 Using air conditioning helps:
• Provides cooling, ventilation and humidity control for all parts of a
building
• Provide human thermal comfort, improved air quality, silent operation,
reduce humidity and controllable comfort
 To maintain indoor air conditions:
• Sealed windows

4. Jet fan system
 Found in the basement or enclose car parking
space
 Provides either normal ventilation and help
extract smoke during fire, or both
 Includes 3 ventilations elements:
• Carbon monoxide detection sensors
• Control panel
• Computational fluid dynamics (CFD) analysis

5. How does it work?
 Operates similarly to a ducted system
• Ventilates the air from top to bottom, creating a continuous flow of air
• Prevents air being trap in certain areas
 In the event of a fire:
• Easily control areas of the ventilation system
• Control the overpressure of the fire fighting zones and the under pressure
of the site of fire
 Not affected by external weather conditions:
• Wind and pressure
• Conditions where cold air tend to stay within human height

6. 1) 2)
3)

7. Centralized air conditioning system
 Consists of 2 parts which are separated
 Outdoor unit:
• Electrical components
• Condenser coil
• Compressor and fan
 Series of pipes and ducts that are connected between the outdoor
unit and indoor unit
 Indoor unit:
• Evaporator coil
• Refrigerant
• Thermostat

8. How does it works?
Refrigerant flows
through a closed loop
system of refrigerant
lines
Warm air in the building
is absorbed into
ductwork by a
motorized fan.
Exterior compressor coil
pumps the refrigerant
into the interior
evaporator coil where
heat from the air is
absorbed
Air is cooled and
transported through
connecting ducts to
vents throughout the
building

9. Refrigerant system flow chart

10. Packaged air cooled chiller
 Consists of:
• Tank
• pumps
• microprocessor controls
• expansion valve
• Compressor
• Evaporator
• Condenser
 ‘plug and play’ design
closed-loop systems
• Reduce maintenance
cost
• Lowers lifetime cost

12. Cooling Tower
 Installed on the rooftop to allow
optimum ventilation
 Components:
• Fan
• Fan motor and guard
• Suction tank
• Sprinkler
• Pipe
• outlet
 Considered the final stage of heat
transfer

14. How does it work?
Heat from building
transferred to chilled
water, then to
refrigerant and to
cooling water
Heat removed from
cooling water when
making contact with
moving air
Water is dispersed and
allow to drizzle
Heat is released into
atmosphere

15. Air Handling Unit (AHU)
 Re-condition and circulate air as part of a heating, ventilating and air-conditioning
system
• re-condition outdoor air and release the fresh air into the building
 Depending on the desired
temperature, fresh air is
either:
• Heated by heating coil
• Cooled by cooling coil

16. Components of AHU
1. Supply Duct
2. Fan Compartment
3. Vibration Isolators
4. Heating and/or
Cooling Coil
5. Filter Compartment
6. Return air duct

17. Control: Multi-Zone Variable Air Volume (VAV)
 Located in server and control
room
 Use less power consumption
 Why?
• Smaller area
• Requires a 24-hours use of air
conditioning system

18. Control: Underfloor air distribution
 Used on every floor
 Provides conditioned air by using an underfloor plenum beneath a raised floor
 Since air is supplied in much closer proximity to the users, supply air
temperature is much higher than conventional overhead system
• Task/ambient conditioning (TAC) system is used to control thermal comfort
conditions

19. How does it work?
Conditioned air supplied
from AHU forms a
reservoir of fresh cool
air by spreading across
the floor
Contaminated air or any
heat sources is lifted to
high level to be
discharged from the
area

20. Diffuser
 Floor swirl diffuser
• Installed on every floor
• Act as the supply and air diffuser on every
floor except lobby
 Ceiling diffuser
• Only installed on first floor lobby area
• Act as return air diffusers