air conditioning system note
Post on 02-Jun-2018
221 views
Embed Size (px)
TRANSCRIPT
8/10/2019 Air Conditioning System Note
1/34
Dengan nama Allah yang
maha pemurah lagi mahapenyayang..
Ya Tuhanku, lapangkanlah
dadaku dalam menjalankan
tugasku, bukalah simpulan
lidahku supaya muridku
memahami setiap
perkataanku.
1
8/10/2019 Air Conditioning System Note
2/34
8/10/2019 Air Conditioning System Note
3/34
Air conditioning is the treatment of theair to:
Control temperature
Control Humidity
An air conditioner is an appliance, system,or mechanism designed to extract heat from an area usinga refrigeration cycle. In construction, a complete system ofheating, ventilation and air conditioning is referred to asHVAC".
Provide ventilation or air movement
Clean the air
3
8/10/2019 Air Conditioning System Note
4/34
Other definition
Air conditioning is the process to control andmaintenance the air in space or enclosed areas.
Mechanical treatments performed on thetemperature, humidity, air renewal, cleanliness
and distribution of air to achieve the requirementsand functions of an item.
Air Conditioning is the process of treating air in aninternal environment to establish and maintain
requirement standards of temperature, humidity,cleanliness, and motion.
4
8/10/2019 Air Conditioning System Note
5/34
Basic principles are based on mass characteristicwith temperature, heat and pressure
Is the treatment of air inenclosed space to control and
to maintain temperature, heat
and pressure together
ASHRAE STANDARD definition:
Air conditioning is the process whereby the condition of air,as defines by its temperature an moisture content, is changed.
Other factors must also be taken into account especiallycleanliness; odor; velocity & distribution pattern.
5
8/10/2019 Air Conditioning System Note
6/34
6
8/10/2019 Air Conditioning System Note
7/34
Evaporator (The cooling coil)
A heat exchanger wherethe heat from the area or item being cooled is transferredto the refrigerant. Change the form of refrigerant liquid togas.Compressor creates the pressure differences or increase
the gas pressure in the system that needed to makerefrigerant flow and the refrigeration cycle work.
Condenser A heat exchanger where the heat absorbedby the refrigerant is transferred to the outdoor air oranother cooler substance. Change the form of refrigerant
gas to liquid Expansion device (The expansion valve) provides a
pressure drop that lowers the boiling point of therefrigerant just before it enters the evaporator. This is alsoknown as the metering device.
7
8/10/2019 Air Conditioning System Note
8/34
8
8/10/2019 Air Conditioning System Note
9/34
The major pieces of equipment required to complete the air-conditioning cycle are listed as follows:
fan
supply ducts
supply outlets
space to be conditioned
return outlets
return ducts filter
heating coil (combustion chamber) or cooling coil
9
8/10/2019 Air Conditioning System Note
10/34
10
8/10/2019 Air Conditioning System Note
11/34
The Fan
The fan moves air to and from an enclosed space. In an air-conditioning system, fan moves air that consists of:
all outdoor air
all indoor or room air
a combination of outdoor and indoor air
The fan pulls air from the outdoor and from the room at the same time.Since drafts in the room cause discomfort, and poor air movementslows the body heat rejection process, it is necessary to regulate theamount of air supplied by the fan. To accomplish this regulation a fan is
selected that can deliver the correct amount of air. By controlling thespeed of the fan, the air stream in the room can be regulated toprovide good circulation without drafts.
11
8/10/2019 Air Conditioning System Note
12/34
12
8/10/2019 Air Conditioning System Note
13/34
The supply duct
The supply duct directs the air from the fan to the room. Atypical duct arrangement is shown below. The supply ductshould be as short as possible and have a minimum number ofturn to ensure that the air can flow freely.
Supply Duct
13
8/10/2019 Air Conditioning System Note
14/34
Supply Outlets
Supply outlets help to distribute the air evenly in a room. Some outlets
fan the air and other outlets direct the air in a jet stream. Still otheroutlets combine these actions.
As a result of these actions, the outlets are able to exert some controlon the direction of the air delivered by the fan. This directionalcontrol plus the location and the number of outlets in the roomcontribute greatly to the comfort or discomfort resulting from the air
pattern.
14
Room Space
The room or the space to be conditioned is one of the most importantparts of the air cycle. If an enclosed space does not exist, then it isimpossible to complete the air cycle.
8/10/2019 Air Conditioning System Note
15/34
Return Outlets
As stated previously, return outlets allow room air to enter thereturn duct. The main function of the return outlet is to allow airto pass from the room. These outlets are usually located on theopposite wall from the supply outlet. For example, if the supplyduct is on the ceiling, or on the wall near the ceiling, then thereturn duct may be located on the floor or on the wall near
the floor.
This situation is not true in all installations, however. Some systemsare provided with both the supply and the return near thefloor or near the ceiling.
15
8/10/2019 Air Conditioning System Note
16/34
Filters
Filters clean the air by removing dust, suspended particles, contaminants and
odours. Filters are located within the return air duct. These devices are made
of many materials including spun glass and composition plastic.
Other filter materials maintain an electrostatic charge, and attract and capturedust and dirt particles from the air flowing through them.
There are 4 classification for filters:
i. Dry
ii. Viscous
iii. Electrostatic
iv. Activated Carbon
16
Dry Filter- producedfrom paper, finewoven fabric,
foamed plastic orglass fibers.
Electrostatic Filter-very expensive,extremely efficientof removing fineparticles, pollens,smoke.
Viscous Filter comprise rows ofcorrugated metal sheets withsurface coated in a non-
flammable, non toxic odourlessoil.
Activated Carbon Filter-location in cooker hood. Veryabsorbent and special designfor use in greasy and odoursatmosphere.
8/10/2019 Air Conditioning System Note
17/34
1. Performance requirementsOn comfort, noise, control options, flexibility and meetingrequirements of local regulations/codes
2. Capacity requirements
Range of capacity, multiple units, zoning, etc.3. Spatial requirement
Plant room space, space for ducting and piping (verticalshafts),space for terminal equipment
4. CostsInitial cost, operating cost and maintenance cost
5. Energy consumptionFor both economic and environment reasons
6. System qualitiesAesthetics, life, reliability and maintainability
17
8/10/2019 Air Conditioning System Note
18/34
18
AC system
Unit System Window Unit
Package Unit
Split unit
Water and air cooling
Air cooling
Water cooling
Split unit without
outdoor air
Split unit with outdoor
airPlant system
Air Handling unit
Centralized system
8/10/2019 Air Conditioning System Note
19/34
19
8/10/2019 Air Conditioning System Note
20/34
A. Unit systems
i) Split system
In split system, the condenser and compressor arelocated in an outdoor unit but the evaporatoris located inside the building.
Typically, the evaporator is mounted in the airhandler unit.
ii) Packaged System In a packaged system, as the name suggests, all
components the condenser, the compressorand the evaporator are located in a single
outdoor unit. The entire unit is generally located on the groundor on the roof.
Packaged systems are generally used when thereis limited space.
20
8/10/2019 Air Conditioning System Note
21/34
A split air conditioner splits the hot side from the coldside system, like this:
21
8/10/2019 Air Conditioning System Note
22/34
22
8/10/2019 Air Conditioning System Note
23/34
- With the packaged system, all the components which may
also include heating coils or a furnace , are located in a singlecabinet- The cabinet is located on the roof of the structure or on theconcrete slab next to the structures foundation.
23
8/10/2019 Air Conditioning System Note
24/34
24
8/10/2019 Air Conditioning System Note
25/34
iii. Window unit
Window units (also known as room units), are designedto air condition a portion of the residence.
The capacity of such a unit is designed so that a givenunit size is adequate to condition one room.
Thus, a unit in a larger size is satisfactory for more thanone room.
If the unit is to be used for more than one room;however, the arrangement of the rooms must insuregood airflow.
Although a unit may be designed to air condition onlyone room, several wind