air conditioning system note

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    Dengan nama Allah yang

    maha pemurah lagi mahapenyayang..

    Ya Tuhanku, lapangkanlah

    dadaku dalam menjalankan

    tugasku, bukalah simpulan

    lidahku supaya muridku

    memahami setiap

    perkataanku.

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    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

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    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.

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    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.

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    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.

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    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

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    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.

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    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

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    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.

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    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.

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    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.

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    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

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    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.

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    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

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    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

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    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.

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    A split air conditioner splits the hot side from the coldside system, like this:

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    - 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.

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    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