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M. Muddaser Sharif 07-NTU-087M. Aqeel Tanoli 07-NTU-083
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HVAC stands forheating
ventilatingair, conditioned system
Heating, ventilating, and air conditioning is based oninventions
and discoveries made by
Nikolay Michael Faraday
Willis CarrierReuben TraneSadi Carnot and many others.
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y HVAC System provides,
HeatingCoolingHumidity controlFiltration
Fresh airBuilding pressure controlComfort control
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Thermal comfortIndoor air quality
HVAC System
heating cooling ventilating
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HVAC system design is a major sub discipline of mechanical
engineering based on the principlesof
1. Thermodynamics
2. Fluid mechanics3. Heat transfer.
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Central heating system Forced air system
Heating system
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Is used in cold climates to heat private houses& public
buildings by using
Furnace
BoilerHeat pump
To heat Water
steam Air
in the central location
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HEATING
The invention of central heating is often credited to the
ancient Romans whoinstalled a system of air ducts called a
hypocaust in the walls and floors of public baths and private
villas
Central Heating can also be provided from
1. Electric Heating2. Solar Heating
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A forced air system is one which uses air as its heat
transfermedium it rely on ducts & vents. Regardless of type all
air handlersystem consist of
Air filter
Blower
Heat exchanger
Element
Coils
And various control
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Ventilating is the process of "changing" or replacing air in any
space to control temperature or remove
MoistureOdorsSmokeHeat
Dust
Airborne bacteriaCarbon dioxide and to replenish oxygen.
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Types
Ventilation
HybridNaturalMechanical/forced
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NATURAL VENTILATION
Natural ventilation is the ventilation of a building with
outsideair without the use of a fan or other mechanical system. It
can beachieved with openable windows or trickle vents.
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Mechanical" or "forced" ventilation is a ventilationin which we
use some mechanical systems like fan for ventilating purpose and it
is used to control indoor air quality.
Mechanical ventilation is used To controlIndoor air quality
Excess humidity Odours
Excess moisture With outside air
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Hybrid Ventilation Also called mixed mood ventilation.
It used both ventilations mechanical & natural.These
ventilations can be used at the same time& also separately
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Air conditioning and refrigeration areprovided through the
removal of heat.
The definition of cold is the absence of heatand all air
conditioning systems work on thisbasic principle.
Heat can be removed through the process of radiation ,
convection, and Heat coolingthrough a process called the
refrigerationcycle.
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The conduction mediums such as water, air, ice,and chemicals are
referred to as refrigerants.
An air conditioning system, or a standalone airconditioner,
provides cooling, ventilation, andhumidity control for all or part
of a house orbuilding.
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REFRIGERANT CYCLE
The refrigerant cycle consists of four essential elements to
createa cooling effect. The system refrigerant starts its cycle in
a gaseous state.The compressor pumps the refrigerant gas up to a
high pressure andtemperature. From there it enters a heat exchanger
(sometimes called a"condensing coil") where it loses energy (heat)
to the outside. In the
process the refrigerant condenses into a liquid.The liquid
refrigerant is returned indoors to
another heat exchanger ("evaporating coil"). A metering device
allows the liquid to flowin at a low pressure at the proper rate.
As the liquid refrigerant evaporates it
aborbs energy (heat) from the inside air,returns to the
compressor, and the cyclerepeats. In the process, heat is
absorbed
from indoors, and transferred outdoors,resulting in cooling of
the building.
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