zobdet el takyeef

7/27/2019 Zobdet El Takyeef

1/42

Introduction

Chapter one: Types of Air Conditioners

There are various types of air conditioning systems. The application of a particular typeof system depends upon a number of factors like how large the area is to be cooled, thetotal heat generated inside the enclosed area, etc. An HVAC designer would considerall the related parameters and suggest the system most suitable for your space.

Window Air Conditioner

Window air conditioneris the most commonly used air conditioner for single rooms. Inthis air conditioner all the components, namely the compressor, condenser, expansionvalve or coil, evaporator and cooling coil are enclosed in a single box. This unit is fittedin a slot made in the wall of the room, or often a window sill.

Must Read:Parts of Window Air Conditioners

Split Air Conditioner

Thesplit air conditionercomprises of two parts: the outdoor unit and the indoor unit.The outdoor unit, fitted outside the room, houses components like the compressor,condenser and expansion valve. The indoor unit comprises the evaporator or coolingcoil and the cooling fan. For this unit you dont have to make any slot in the wall of the

room. Further, the present day split units have aesthetic looks and add to the beauty ofthe room. The split air conditioner can be used to cool one or two rooms.

Packaged Air Conditioner

Packaged air conditioner: An HVAC designer will suggest this type of air conditioner ifyou want to cool more than two rooms or a larger space at your home or office. Thereare two possible arrangements with the package unit. In the first one, all thecomponents, namely the compressor, condenser (which can be air cooled or watercooled), expansion valve and evaporator are housed in a single box. The cooled air isthrown by the high capacity blower, and it flows through the ducts laid through various

rooms. In the second arrangement, the compressor and condenser are housed in onecasing. The compressed gas passes through individual units, comprised of theexpansion valve and cooling coil, located in various rooms.

Must read:

1)Packaged Air Conditioners - Types of Packaged AC
http://www.brighthub.com/engineering/mechanical/articles/898.aspxhttp://www.brighthub.com/engineering/mechanical/articles/898.aspxhttp://www.brighthub.com/engineering/mechanical/articles/55186.aspxhttp://www.brighthub.com/engineering/mechanical/articles/55186.aspxhttp://www.brighthub.com/engineering/mechanical/articles/55186.aspxhttp://www.brighthub.com/tools/http://www.brighthub.com/tools/http://www.brighthub.com/tools/http://www.brighthub.com/engineering/mechanical/articles/61457.aspxhttp://www.brighthub.com/engineering/mechanical/articles/61457.aspxhttp://www.brighthub.com/engineering/mechanical/articles/61457.aspxhttp://www.brighthub.com/engineering/mechanical/articles/61457.aspxhttp://www.brighthub.com/engineering/mechanical/articles/61457.aspxhttp://www.brighthub.com/engineering/mechanical/articles/61457.aspxhttp://www.brighthub.com/engineering/mechanical/articles/61457.aspxhttp://www.brighthub.com/tools/http://www.brighthub.com/engineering/mechanical/articles/55186.aspxhttp://www.brighthub.com/engineering/mechanical/articles/898.aspx


2/42

2)Compressors and Capacity Control System in the Packaged Air Conditioners

Central Air Conditioning System

4)Central air conditioning system: The central air conditioning system is used for

cooling big buildings, houses, offices, entire hotels, gyms, movie theaters, factories etc.If the whole building is to be air conditioned, HVAC engineers find that putting individualunits in each of the rooms is very expensive initially as well in the long run. The centralair conditioning system is comprised of a huge compressor that has the capacity toproduce hundreds of tons of air conditioning. Cooling big halls, malls, huge spaces,galleries etc is usually only feasible with central conditioning units.

Must Read:

1)Central Air Conditioning Plants

2)Direct Expansion or DX Type of Central Air Conditioning Plant

3)Chilled Water Type of Central Air Conditioning Plant

Types of Air Conditioners

Chapter 2 : Window Air Conditioning System

Window air conditioners are one of the most commonly used and cheapest type of airconditioners. To install one of these units, you need the space to make a slot in the wall,and there should also be some open space behind the wall.

Window air conditioners are one of the most populartypes of air conditionersbeing used.Whether its your study room, bedroom, or hall, the window airconditioner can be used for
http://www.brighthub.com/engineering/mechanical/articles/905.aspxhttp://www.brighthub.com/engineering/mechanical/articles/905.aspxhttp://www.brighthub.com/engineering/mechanical/articles/905.aspxhttp://www.brighthub.com/engineering/mechanical/articles/906.aspxhttp://www.brighthub.com/engineering/mechanical/articles/906.aspxhttp://www.brighthub.com/engineering/mechanical/articles/906.aspxhttp://www.brighthub.com/engineering/mechanical/articles/906.aspxhttp://www.brighthub.com/engineering/mechanical/articles/906.aspxhttp://www.brighthub.com/engineering/mechanical/articles/906.aspxhttp://www.brighthub.com/engineering/mechanical/articles/906.aspxhttp://www.brighthub.com/engineering/mechanical/articles/50158.aspxhttp://www.brighthub.com/engineering/mechanical/articles/50158.aspxhttp://www.brighthub.com/engineering/mechanical/articles/50158.aspxhttp://www.brighthub.com/engineering/mechanical/articles/50160.aspxhttp://www.brighthub.com/engineering/mechanical/articles/50160.aspxhttp://www.brighthub.com/engineering/mechanical/articles/50160.aspxhttp://www.brighthub.com/article/Types-of-Air-Conditioning-Systems/Haresh-Khemani/558.htmlhttp://www.brighthub.com/article/Types-of-Air-Conditioning-Systems/Haresh-Khemani/558.htmlhttp://www.brighthub.com/article/Types-of-Air-Conditioning-Systems/Haresh-Khemani/558.htmlhttp://www.brighthub.com/engineering/mechanical/articles/897.aspx?image=39880http://www.brighthub.com/engineering/mechanical/articles/897.aspx?image=39879http://www.brighthub.com/engineering/mechanical/articles/897.aspx?image=39878http://www.brighthub.com/engineering/mechanical/articles/897.aspx?image=39877http://www.brighthub.com/engineering/mechanical/articles/897.aspx?image=39880http://www.brighthub.com/engineering/mechanical/articles/897.aspx?image=39879http://www.brighthub.com/engineering/mechanical/articles/897.aspx?image=39878http://www.brighthub.com/engineering/mechanical/articles/897.aspx?image=39877http://www.brighthub.com/engineering/mechanical/articles/897.aspx?image=39880http://www.brighthub.com/engineering/mechanical/articles/897.aspx?image=39879http://www.brighthub.com/engineering/mechanical/articles/897.aspx?image=39878http://www.brighthub.com/engineering/mechanical/articles/897.aspx?image=39877http://www.brighthub.com/engineering/mechanical/articles/897.aspx?image=39880http://www.brighthub.com/engineering/mechanical/articles/897.aspx?image=39879http://www.brighthub.com/engineering/mechanical/articles/897.aspx?image=39878http://www.brighthub.com/engineering/mechanical/articles/897.aspx?image=39877http://www.brighthub.com/article/Types-of-Air-Conditioning-Systems/Haresh-Khemani/558.htmlhttp://www.brighthub.com/engineering/mechanical/articles/50160.aspxhttp://www.brighthub.com/engineering/mechanical/articles/50158.aspxhttp://www.brighthub.com/engineering/mechanical/articles/906.aspxhttp://www.brighthub.com/engineering/mechanical/articles/906.aspxhttp://www.brighthub.com/engineering/mechanical/articles/906.aspxhttp://www.brighthub.com/engineering/mechanical/articles/905.aspx


3/42

almost all types of spaces.

To fit the window air conditioner in your room, you need to make a slot in one of the walls of theroom that is to be cooled. This system extends around two feet beyond the wall in the back side;hence behind the wall some free space should be available so that the hot air can be throwneasily from the condenser. The dew collected from the room is also thrown from the back of the

air conditioner. Thus window air conditioners can be used only if there is place available in thewall to make the slot, and there is free space behind the wall for dissipating the heat anddripping water.

Window air conditioners are comprised of components like the compressor, condenser,expansionvalveor expansion coil, and the evaporator or the cooling coil, all housed in a singlebox. There is also a motor which has shafts on both sides. On one side of the shaft the blower isconnected, which sucks hot air from the room and blows it over the cooling coil, thus cooling itand sending it to the room. On the other shaft the fan is connected, which blows the air overFreon gas passing through the condenser.

The window air conditioner is the cheapest of allair conditioningsystems. If your room or office

size is about less than 100 sq. ft. a window air conditioner of about 0.8 ton can be good enough.If the size of room is more than this but less than 200 sq. ft. your HVAC designer willrecommend a window air conditioner of about 1 ton. For rooms of bigger sizes but less than 300sq. ft. the system of about 1.5 ton is advisable. However, these sizes may change dependingupon the number of people occupying the space, its alignment with respect to sun, and othersources of heat generation inside the room. It is better to consult your HVAC designer to find outthe exact size of window air conditioner suitable for your space.

One of the complaints that window air conditioners have had is that they tend to make noiseinside the room. But this problem has been greatly overcome by the present day efficient andless noisy rotary compressors, which also consume less electricity. Today a number of fancyand elegant looking models of window air conditioners are available that enhance the beauty of

your rooms.

Chapter 3 : Split Air Conditioner System

Split air conditioners are used for small rooms and halls, usually in places wherewindow air conditioners cannot be installed. However, these days many people prefer

split air conditioner units even for places where window air conditioners can be fitted.

Do you have a single room but no place to make a slot for thewindow air conditioner?

yesssssssssssss
http://www.brighthub.com/guides/valve.aspxhttp://www.brighthub.com/guides/valve.aspxhttp://www.brighthub.com/guides/valve.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/article/Window-Air-Conditioning-System/Haresh-Khemani/559.htmlhttp://www.brighthub.com/article/Window-Air-Conditioning-System/Haresh-Khemani/559.htmlhttp://www.brighthub.com/article/Window-Air-Conditioning-System/Haresh-Khemani/559.htmlhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/valve.aspx


4/42

No problem, there is an excellent option in the form of a split air conditioner. The split airconditioner can be installed in rooms and offices where you dont want to disturb thesetup of the room and avoid demolitions in your favorite space. The split air conditionertakes up a very small space of your room, looks aesthetically cool and makes very littlenoise, ensuring sound sleep for you when you return from your days hard work.

There are two main parts of the split air conditioner. These are:

1) Outdoor unit: This unit houses important components of the air conditioner like thecompressor, condenser coil and also the expansion coil or capillary tubing. This unit isinstalled outside the room or office space which is to be cooled. The compressor is themaximum noise making part of the air conditioner, and since in the split air conditioner,it is located outside the room, the major source of noise is eliminated. In the outdoor unitthere is a fan that blows air over the condenser thus cooling the compressed Freon gasin it. This gas passes through the expansion coil and gets converted into low pressure,low temperature partial gas and partial liquid Freon fluid.

2) Indoor unit: It is the indoor unit that produces the cooling effect inside the room orthe office. This is a beautiful looking tall unit usually white in color, though these days anumber of stylish models of the indoor unit are being launched. The indoor unit housesthe evaporator coil or the cooling coil, a long blower and the filter. After passing from theexpansion coil, the chilled Freon fluid enters the cooling coil. The blower sucks the hot,humid and filtered air from the room and it blows it over the cooling coil. As the airpasses over cooling coil its temperature reduces drastically and also loses the excessmoisture. The cool and dry air enters the room and maintains comfortable conditions ofaround 25-27 degree Celsius as per the requirements.

The temperature inside the space can be maintained by thermostat setting. The settingshould be such that comfortable conditions are maintained inside the room, and there is

also chance for the compressor to trip at regular intervals. If the compressor keepsrunning continuously without break, its life will reduce.

These days multi-split air conditioners are also being used commonly. In units for oneoutdoor unit there are two indoor units which can be placed in two different rooms or attwo different locations inside a large room.
http://www.brighthub.com/engineering/mechanical/articles/904.aspx?image=61


5/42

Since there is long distance between the indoor and the outdoor unit, there is alwaysloss of some cooling effect; hence for the same tonnage, split air conditioners producesomewhat less cooling effect thanwindow air conditioners. However, with moderninsulation material this gap has been reducing between the two. In any case, there arenumber of instances where there is just no alternative to the split air conditioners.

Must read:

1) Parts of the Split Air Conditioner

1- Parts of the Split Air Condioners: Outdoor Unit

The split air conditioner is one of the most widelyused type of the air conditioners. The major

reasons behind the popularity if split airconditioner are their silent operation and elegantlooks. Let us see the various parts of these units.

Introduction

The split air conditioner is one of the most widely used type of the air conditioners.Earlier window air conditioner was used most widely, but the split air conditioner is nowcatching up with it. The major reasons behind the popularity if split air conditioner are

their silent operation and elegant looks. Another advantage of the split air conditioner isthat you don't have to make the hole in the wall of the air conditioner and destroy thebeauty of the room. These days the indoor units of the split air conditioner are availablein wide range of color and designs.

There are two main parts of the split air conditioner: the indoor unit and the outdoor unit(see fig below). The indoor unit of the split AC is installed inside the room that is to beair conditioned or cooled while the outdoor unit is installed outside the room in openspace where the unit can be installed and maintained easily. Apart from these two majorparts there is copper tubing connecting the indoor and the outdoor units. Let us seethe various parts of the indoor and the outdoor units of the split ACs.
http://www.brighthub.com/article/Window-Air-Conditioning-System/Haresh-Khemani/559.htmlhttp://www.brighthub.com/article/Window-Air-Conditioning-System/Haresh-Khemani/559.htmlhttp://www.brighthub.com/article/Window-Air-Conditioning-System/Haresh-Khemani/559.htmlhttp://www.brighthub.com/engineering/mechanical/articles/45046.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45046.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45046.aspxhttp://www.brighthub.com/article/Window-Air-Conditioning-System/Haresh-Khemani/559.html


6/42

Parts of Split Conditioner

Outdoor Unit

As mentioned previously the outdoor unit is installed outside the room to be airconditioned in the open space. In outdoor unit lots of heat is generated inside the

compressor and the condenser, hence there should be sufficient flow of the air aroundit. The outdoor unit is usually installed at the height above the height of the indoor unitinside the room though in many cases the outdoor is also installed at level below theindoor unit.

The outdoor unit contains the important parts of the split AC like compressor,condenser, expansion valve etc. Let us see these parts in more details:

1) Compressor:

The compressor is most important part of the any air conditioner. It compresses the

refrigerant and increases its pressure before sending it to the condenser. The size ofthe compressor varies depending on the desired air conditioning load. In most of thedomestic split air conditioners hermetically sealed type of compressor is used. In suchcompressors the motor used for driving the shaft is located inside the sealed unit and itis not visible externally. External power has to be supplied to the compressor, which isutilized for compressing the refrigerant and during this process lots of heat is generatedin the compressor, which has to be removed by some means.

2) Condenser:

The condenser used in the outdoor unit of split air conditioners is the coiled coppertubing with one or more rows depending on the size of the air conditioning unit and thecompressor. Greater the tonnage of the air conditioner and the compressor more arethe coil turns and rows. The high temperature and high pressure refrigerant from thecompressor comes in the condenser where it has to give up the heat. The tubing ismade up of coppersince it rate of conduction of heat is high . The condenser is alsocovered with the aluminum fins so that the heat from the refrigerant can be removed atmore faster rate.
http://www.brighthub.com/engineering/mechanical/articles/45044.aspx?image=55239http://www.brighthub.com/engineering/mechanical/articles/45044.aspx?image=55238http://www.brighthub.com/engineering/mechanical/articles/45044.aspx?image=55237http://www.brighthub.com/engineering/mechanical/articles/45044.aspx?image=55239http://www.brighthub.com/engineering/mechanical/articles/45044.aspx?image=55238http://www.brighthub.com/engineering/mechanical/articles/45044.aspx?image=55237http://www.brighthub.com/engineering/mechanical/articles/45044.aspx?image=55239http://www.brighthub.com/engineering/mechanical/articles/45044.aspx?image=55238http://www.brighthub.com/engineering/mechanical/articles/45044.aspx?image=55237


7/42

3) Condenser Cooling Fan:

The heat generated within the compressor has to be thrown out else the compressorwill get too hot in the long run and its motor coils will burn leading to completebreakdown of the compressor and the whole air conditioner. Further, the refrigerantwithin the condenser coil has to be cooled so that after expansion its temperaturebecome low enough to produce the cooling effect. The condenser cooling fan is an

ordinary fan with three or four blades and is driven by a motor. The cooling fan islocated in front of the compressor and the condenser coil. As the blades of the fanrotate it absorbs the surrounding air from the open space and blows it over thecompressor and the condenser with the aluminum fins thus cooling them. The hot air isthrown back to the open space and the circulation of air continues unhindered.

4) Expansion Valve:

The expansion valve is usually a copper capillary tubing with several rounds of coils. Inthe split air conditioners of bigger capacities thermostatic expansion valve is used which

is operated electronically automatically. The high pressure and medium temperaturerefrigerant leaves the condenser and enters the expansion valve, where its temperatureand pressure drops suddenly.

Parts of the Split Air Conditioner: Refrigerant Piping or Tubing

2- The refrigerant piping is made up of coppertubing and it connects the indoor and the outdoorunit. Let us see the importance of refrigerant

tubing and its materials.

Split Air Conditioner
http://www.brighthub.com/engineering/mechanical/articles/45044.aspx?image=21601


8/42

Refrigerant Piping or TubingThe refrigerant piping is made up of copper tubing and it connects the indoor and theoutdoor unit (see images above). The refrigerant at low temperature and low pressureleaves the expansionvalveand enters the copper tubing, which is connected to theevaporator or the cooling coil at the other end.

The distance between the indoor and the outdoor unit can be short or long dependingon the distance at which the open space is available in the home or office building. Thelonger the distance longer is the refrigerant piping between the two. When therefrigerant flows from the outdoor unit to the indoor unit in the tubing there is some lossof the cooling effect on the way, hence the distance between the indoor and the outdoorunit should be kept as minimum as possible. For the distance up to 15 meters there isnot much appreciable loss of the cooling effect, however beyond that the lossesbecome higher.

The refrigerant inside the tubing is at very low temperature and length of piping betweenand outdoor unit and indoor unit is quite long. Further, the tubing is exposed to the open

atmosphere which is at very high temperature. Due to this, if the tubing is left uncoveredall the cooling effect will be lost to the open atmosphere and by the time the refrigerantenters the cooling coil its temperature will already be too high and the purpose ofproducing the cooling effect will not be served. To avoid this, the refrigerant tubingconnecting the indoor and the outdoor unit is covered with the insulation. This preventsthe loss of the cooling effect to the atmosphere and low temperature refrigerant willproduce the desired cooling effect inside the room.

After producing the cooling effect inside the room in the indoor unit, the refrigerant hasto come back to the outdoor unit for getting compressed and re-circulating. There isanother refrigerant tubing that connects the indoor and the outdoor unit so that the

refrigerant can travel from cooling coil back to the compressor. This tubing is alsocovered with insulation so that the refrigerant enters the compressor at minimumpossible temperature to increase therefrigerationefficiency of the air conditioner. Thusthere are two tubing connecting the indoor and the outdoor unit and both are coveredwith the insulation tape.

The refrigerant tubing are made up of copper since it is highly ductile and malleableelement. The tubing can be easily manufactured from this material and they are flexible
http://www.brighthub.com/guides/valve.aspxhttp://www.brighthub.com/guides/valve.aspxhttp://www.brighthub.com/guides/valve.aspxhttp://www.brighthub.com/guides/refrigeration.aspxhttp://www.brighthub.com/guides/refrigeration.aspxhttp://www.brighthub.com/guides/refrigeration.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45045.aspx?image=55242http://www.brighthub.com/engineering/mechanical/articles/45045.aspx?image=55241http://www.brighthub.com/engineering/mechanical/articles/45045.aspx?image=55240http://www.brighthub.com/engineering/mechanical/articles/45045.aspx?image=55242http://www.brighthub.com/engineering/mechanical/articles/45045.aspx?image=55241http://www.brighthub.com/engineering/mechanical/articles/45045.aspx?image=55240http://www.brighthub.com/engineering/mechanical/articles/45045.aspx?image=55242http://www.brighthub.com/engineering/mechanical/articles/45045.aspx?image=55241http://www.brighthub.com/engineering/mechanical/articles/45045.aspx?image=55240http://www.brighthub.com/guides/refrigeration.aspxhttp://www.brighthub.com/guides/valve.aspx


9/42

enough so they can turned into angles and coiled easily. The copper tubing used forcondenser and evaporator facilitate high rate of heat conduction.

3- Parts of the Split Air Conditioner: Wall

Mounted Indoor UnitThe indoor unit of the split air conditioner is a box type housing in which all the importantparts of the air conditioner are enclosed. The most common type of the indoor unit is thewall mounted type though other types like ceiling mounted and floor mounted are alsoused.

Split Air Conditioner with Wall Mounted Indoor Unit

Wall Mounted Indoor Unit

It is the indoor unit that produces the cooling effect inside the room. The indoor unit of

the split air conditioner is a box type housing in which all the important parts of the airconditioner are enclosed. The most common type of the indoor unit is the wall mountedtype though other types like ceiling mounted and floor mounted are also used. We shalldiscuss all these types in separate articles, here we shall discuss the wall mounted typeof the indoor unit.

These days the companies give utmost importance to the looks and aesthetics of theindoor unit. In the last couple few years the purpose of the indoor unit has changed frombeing a mere cooling effect producing devise to a beautiful looking cooling deviseadding to the overall aesthetics of the room. This is one of the major reasons that thepopularity of the split units has increased tremendously in the last few years. Let us see

the various parts enclosed inside the indoor unit of the split air conditioner:

1) Evaporator Coil or the Cooling Coil:

The cooling coil is a copper coil made of number turns of the copper tubing with one ormore rows depending on the capacity of theair conditioningsystem. The cooling coil is
http://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45046.aspx?image=55245http://www.brighthub.com/engineering/mechanical/articles/45046.aspx?image=55244http://www.brighthub.com/engineering/mechanical/articles/45046.aspx?image=55243http://www.brighthub.com/engineering/mechanical/articles/45046.aspx?image=55245http://www.brighthub.com/engineering/mechanical/articles/45046.aspx?image=55244http://www.brighthub.com/engineering/mechanical/articles/45046.aspx?image=55243http://www.brighthub.com/engineering/mechanical/articles/45046.aspx?image=55245http://www.brighthub.com/engineering/mechanical/articles/45046.aspx?image=55244http://www.brighthub.com/engineering/mechanical/articles/45046.aspx?image=55243http://www.brighthub.com/guides/air-conditioning.aspx


10/42

covered with the aluminum fins so that the maximum amount of heat can be transferredfrom the coil to the air inside the room.

The refrigerant from the tubing at very low temperature and very low pressure entersthe cooling coil. The blower absorbs the hot room air or the atmospheric air and in doing

so the air passes over the cooling coil which leads to the cooling of the air. This air isthen blown to the room where the cooling effect has to be produced. The air, afterproducing the cooling effect is again sucked by the blower and the process of coolingthe room continues.

After absorbing the heat from the room air, the temperature of the refrigerant inside thecooling coil becomes high and it flows back through the return copper tubing to thecompressor inside the outdoor unit. The refrigerant tubing supplying the refrigerant fromthe outdoor unit to the indoor unit and that supplying the refrigerant from indoor unit tothe outdoor unit are both covered with the insulation tape.

2) Air Filter:The air filter is very important part of the indoor unit. It removes all the dirt particles fromthe room air and helps supplying clean air to the room. The air filter in the wall mountedtype of the indoor unit is placed just before the cooling coil. When the blower sucks thehot room air, it is first passed through the air filter and then though the cooling coil. Thusthe clean air at low temperature is supplied into the room by the blower.

3) Cooling Fan or Blower:

Inside the indoor unit there is also a long blower that sucks the room air or theatmospheric air. It is an induced type of blower and while is sucks the room air it ispassed over the cooling coil and the filter due to which the temperature of the airreduces and all the dirt from it is removed. The blower sucks the hot and unclean airfrom the room and supplies cool and clean air back. The shaft of the blower rotatesinside the bushes and it is connected to a small multiple speed motor, thus the speed ofthe blower can be changed. When the fan speed is changed with the remote it is thespeed of the blower that changes.

4) Drain Pipe:

Due to the low temperature refrigerant inside the cooling coil, its temperature is verylow, usually much below the dew point temperature of the room air. When the room airis passed over the cooling due the suction force of the blower, the temperature of the airbecomes very low and reaches levels below its dew point temperature. Due to this thewater vapor present in the air gets condensed and dew or water drops are formed onthe surface of the cooling coil. These water drops fall off the cooling coil and arecollected in a small space inside the indoor unit. To remove the water from this spacethe drain pipe is connected from this space extending to the some external place


11/42

outside the room where water can be disposed off. Thus the drain pipe helps removingdew water collected inside the indoor unit.

To remove the water efficiently the indoor unit has to be a tilted by a very small angle ofabout 2 to 3 degrees so that the water can be collected in the space easily and drained

out. If this angle is in opposite direction, all the water will get drained inside the room.Also, if the tilt angle is too high, the indoor unit will shabby inside the room.

5) Louvers or Fins:

The cool air supplied by the blower is passed into the room through louvers. Thelouvers help changing the angle or direction in which the air needs to be supplied intothe room as per the requirements. With louvers one easily change the direction in whichthe maximum amount of the cooled air has to be passed.

There are two types of louvers: horizontal and vertical. The horizontal louvers are

connected to a small motor and there position can set by the remote control. Once canset a fixed position for the horizontal louvers so that chilled air is passed in a particulardirection only or one can keep it in rotation mode so that the fresh air is suppliedthroughout the room. The vertical louvers are operated manually and one can easilychange their position as per the requirements. The horizontal louvers control flow of airin upper and downward directions of the room, while vertical louvers control movementof air in left and right directions.

Image Courtesy

1)220V Appliances

2)The Elite Home

2) Installation of the Split Air Conditioners

Installation of the Split Air Conditioners: Deciding the

Location of Indoor and Outdoor Units

The installation of the split air conditioners is themost important and crucial part. If it is done properlyyour air conditioner will give you optimum
http://220voltsappliances.110220volts.com/tag/air-conditioners-220-volts/http://220voltsappliances.110220volts.com/tag/air-conditioners-220-volts/http://220voltsappliances.110220volts.com/tag/air-conditioners-220-volts/http://www.thelitehome.com/air-conditioners/amcor-portable-air-conditioner/amcor-ductless-split-air-conditioners-dfc009-1.htmlhttp://www.thelitehome.com/air-conditioners/amcor-portable-air-conditioner/amcor-ductless-split-air-conditioners-dfc009-1.htmlhttp://www.thelitehome.com/air-conditioners/amcor-portable-air-conditioner/amcor-ductless-split-air-conditioners-dfc009-1.htmlhttp://www.brighthub.com/engineering/mechanical/articles/45249.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45249.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45249.aspxhttp://www.thelitehome.com/air-conditioners/amcor-portable-air-conditioner/amcor-ductless-split-air-conditioners-dfc009-1.htmlhttp://220voltsappliances.110220volts.com/tag/air-conditioners-220-volts/


12/42

performance, but if it is not done properly you won'tget the desired cooling effect and there may befrequent maintenance problems.

IntroductionBy now we have seen thedifferent parts of the split air conditioners, now let us theinstallation of these Acs. The installation of the split air conditioners is the mostimportant and crucial part. If it is done properly your air conditioner will give youoptimum performance, but if it is not done properly you won't get the desired coolingeffect and there may be frequent maintenance problems of which the most prominentcan be the gas or refrigerant leakage. The installation of the split air conditioner shouldbe done by an expertair conditioningtechnician and the task should not be left to anovice person who is experimenting with your AC. It requires lots of practice to becomean expert split AC installation and erection technician.

Various factors have to be considered during the installation of any split air conditioner,here we are going to consider how to do the installation of wall mounted split airconditioner. In other articles we would consider installation of other types of split airconditioners also.

Location of Indoor and Outdoor Units

Location of the Indoor and the Outdoor UnitsThe first step in the installation of split AC is deciding the location of the indoor and theoutdoor units, only then the next important steps of the installation can be initiated. Let

us see the factors to be considered when deciding the location of these units (see theimages below):

1) Indoor Unit:

Here are the important suggestions when deciding the location of indoor unit inside theroom:
http://www.brighthub.com/engineering/mechanical/articles/45044.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45044.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45044.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45249.aspx?image=55318http://www.brighthub.com/engineering/mechanical/articles/45249.aspx?image=55317http://www.brighthub.com/engineering/mechanical/articles/45249.aspx?image=55316http://www.brighthub.com/engineering/mechanical/articles/45249.aspx?image=55318http://www.brighthub.com/engineering/mechanical/articles/45249.aspx?image=55317http://www.brighthub.com/engineering/mechanical/articles/45249.aspx?image=55316http://www.brighthub.com/engineering/mechanical/articles/45249.aspx?image=55318http://www.brighthub.com/engineering/mechanical/articles/45249.aspx?image=55317http://www.brighthub.com/engineering/mechanical/articles/45249.aspx?image=55316http://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45044.aspx


13/42

a) The indoor unit is located inside the room at the location from where the air can bedistributed evenly throughout the room.

b) As far as possible the indoor should be installed above the bed so that the maximumcooling effect can be obtained. It should be located directly above the bed. If one has to

avoid the direct flow of chilled air on the body, one can always change the direction ofthe louvers. The indoor unit can also be installed on wall towards your feet though it canbe installed on other side walls also.

c) The wall mounted indoor unit should be located at the height of about 8 to 10 feetfrom the floor so that that most of the chilled air is used for cooling the room and notmerely for cooling the hot roof.

d) The indoor unit should be accessible easily so that one can conveniently clean thefilter every fortnight and the whole unit and also that one can manually change theposition of the louvers easily.

e) If the indoor unit is installed above certain window, make sure that it is in symmetrywith the window, else the unit will look shabby. The indoor unit is meant to add to theaesthetics of the room and not destroy it.

2) Outdoor Unit:

Here are some points to consider when deciding the location of the outdoor unit:

a) The outdoor unit should be located in the open space preferably on the terrace sothat the air can flow freely over the compressor and the condenser. If the terrace is not

available it can be kept on the awning above the wall or it can be hanged on theexternal wall supported by the angles.

b) The location of outdoor unit should be such that it is easily accessible for carrying outthe maintenance works of the compressor, condenser, and other devices. Theinstallation and gas charging also should be convenient.

c) There should not be any hindrances in front of the outdoor that would block thepassage of fan air from passing to the open space. Any blockages will seriously affectthe performance of the AC and can also lead to the burning of hermetically sealedcompressor coil.

d) The surface on which the outdoor unit is to be installed should be rigid enough toavoid its vibration. The vibration of the outdoor unit will raise excessive noise and alsolead to the breaking of the copper tubing and leakage of the refrigerant.

It is always advisable to keep the outdoor unit at the height above the indoor unit. If theoutdoor unit is kept at level below the indoor, some of the compressor power is used inpumping the refrigerant against the gravity, thus reducing the overall performance of the


14/42

compressor. Most of the outdoor units are quite silent so one does not have to worryabout their noise. The internal parts of the outdoor unit are shielded against the rain andsun rays, so one can rest assured about their safety in different climatic conditions.

The refrigerant at very low temperature flows inside the tubing between indoor and the

outdoor unit, and there is always some loss of refrigerant effect to the atmosphere fromthese tubing, hence the distance between the indoor and the outdoor unit should bekept as minimum as possible to reduce the loss of the cooling effect. The maximumdistance between the indoor and the outdoor units can be about 15 meters.

Installation of the Wall Mounted Indoor Unit

After deciding the location of the indoor and the outdoor unit, the installation of indoor

unit is started. Here are the steps for the installation of wall mounted indoor unit of thesplit air conditioner.


Once the location of the indoor unit is decided its installation can be started. As such theinstallation of the indoor unit is quite easy, but only for those who have mastered thetechnique. The newbie may find the process quite a bit complicated and it requiressome extra efforts to actually install the unit. The wall mounted indoor unit can beinstalled on the wall of the room or the partition at the height of about 8-10 feets fromthe floor. Here are the steps for installation of the indoor unit:


1) Make the markings as per the wall hook bracket:The installation of indoor unit is made easier by the wall hook bracket. It is a sort of thealuminum template with all the necessary holes and the attachments. All one has to doit make the holes in the wall as per the template and then fit the template with screws.
http://www.brighthub.com/engineering/mechanical/articles/45596.aspx?image=55429http://www.brighthub.com/engineering/mechanical/articles/45596.aspx?image=55428http://www.brighthub.com/engineering/mechanical/articles/45596.aspx?image=55427http://www.brighthub.com/engineering/mechanical/articles/45596.aspx?image=55429http://www.brighthub.com/engineering/mechanical/articles/45596.aspx?image=55428http://www.brighthub.com/engineering/mechanical/articles/45596.aspx?image=55427http://www.brighthub.com/engineering/mechanical/articles/45596.aspx?image=55429http://www.brighthub.com/engineering/mechanical/articles/45596.aspx?image=55428http://www.brighthub.com/engineering/mechanical/articles/45596.aspx?image=55427


15/42

For this the air conditioning technician makes the marking of the wall hook bracket onthe wall coinciding with the holes on the bracket. When making the markings for theholes, make sure that the bracket is given slight tilt angle, so that the indoor unit, whenfitted is also at a slight angle to enable unhindered flow of the dew water from the drainpipe.

2) Fit the bracket:

After making the markings for the holes, remove the wall hook bracket and make theholes in the wall with drilling machine at these markings. Thereafter, keep the bracket inplace again on the wall and fit it with the screws in the drilled holes.

3) Make a hole in the wall or partition:

Make a small hole of about 3 inches near the bracket across the wall or partition.

Through this hole the refrigerant tubing connecting the indoor and the outdoor will pass.These tubing are insulated hence they need hole of large diameter. The drain pipethough which the dew water is drained also passes through this whole. Through thishole the power supply cable and electric cable connecting the indoor and the outdoorunit also pass.

4) Installing the indoor unit:

Now, the indoor unit is ready to be fitted on the bracket. Just lift up the unit, it is usuallynot too heavy, and fit it on the wall hook brake bracket. There are some maleextensions on the bracket on which the female counterpart of the indoor unit can be

fitted. When fitting the indoor unit the copper tubing extending from the unit has to bepassed through the hole and to outside the room for connecting it do the outdoor unit.The drain pipe is connected to one end of the indoor unit; it is passed through the holeand left free in the open space where the water can be drained. The power supply cableconnecting the indoor and outdoor unit and to the main supply is also passed throughthe hole.

5) Tilting the indoor unit:

The indoor unit is given slight tilt of about 2-3 degree towards the drain pipe. This

enables unhindered flow of dew water towards the water space where drain water iscollected and drain pipe is connected for removal of water. This angle should be justsufficient to enable flow of water without disturbing the looks of the indoor unit due tohigh angle of tilt. Too small angle will not serve the purpose and high angle will makethe easy looks shabby and also unbalance the blower inside the unit. The level of theunit can be checked with the level bubble gauge.
http://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/electricity.aspxhttp://www.brighthub.com/guides/electricity.aspxhttp://www.brighthub.com/guides/air-conditioning.aspx


16/42

With this the installation of the indoor unit is almost over. It is now ready to beconnected to the refrigerant tubing and the outdoor unit. The power supply cable is yetto be connected.

Image Courtesy

1) Friedrich

Installation of the Outdoor Unit of Split AirConditioners

During installation of the outdoor unit of split AC, selecting the proper location of the unit

is very important the rest of the things are not too complicated. Let us the factorsaffecting the location of the outdoor unit and steps for the installation of the unit.

In the previous article we saw theinstallation of the indoor unit of split AC, now let ussee the installation of the outdoor unit. While the indoor unit is light in weight, theoutdoor unit is quite heavy since it comprises of the heavy components like thecompressor, condenser, fan motor with fan etc. In most of the cases the outdoor unit ofsplit AC has to be installed at certain height so lifting the unit can be a tough taskrequiring about three to four people.

Installation of the Outdoor Unit

Location of the Outdoor Unit of Split ACWe have seen some important points regarding thelocation of the indoor and theoutdoor unit, here we have summarized these points for the outdoor units and haveadded a few more.

1) Install the outdoor unit on flat rigid surface: The outdoor unit should be installedon the flat rigid or concrete base since it is quite heavy. The unit will vibrate excessively
http://www.friedrich.com/downloads/DSS_WM_installation_manual_M24DY3F-M36TQYF(indoor-units).pdfhttp://www.brighthub.com/engineering/mechanical/articles/45596.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45596.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45596.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45249.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45249.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45249.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45249.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45811.aspx?image=55476http://www.brighthub.com/engineering/mechanical/articles/45811.aspx?image=55475http://www.brighthub.com/engineering/mechanical/articles/45811.aspx?image=55476http://www.brighthub.com/engineering/mechanical/articles/45811.aspx?image=55475http://www.brighthub.com/engineering/mechanical/articles/45249.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45249.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45596.aspxhttp://www.friedrich.com/downloads/DSS_WM_installation_manual_M24DY3F-M36TQYF(indoor-units).pdf


17/42

if it is installed on some loose, vibrating or hanging base. If the unit vibrates due to weakbase, the compressor and condenser coil will also vibrate, which can lead to thebreakage of the copper tubing over certain period of time and leakage of the refrigerant.Inside the vibrating compressor the shaft may get unbalanced leading to itsunsymmetrical movement and ultimately burning of the electric coil. Further, the

vibrating unit makes lots of noise which could disturb not only your room but also theneighbors.

2) Free flow of air: The outdoor unit should be installed in the open space on theterrace, above the awning of the window or any other convenient location where there isfree flow of air. There should not be any hindrance to the flow of air around the outdoorunit. There should not be any blockage to the flow of air in front of the outdoor fromwhere the heat is dissipated by hot air. The unit should be easily accessible forinstallation, wiring, and carrying out any maintenance works in future. As far as possiblethe outdoor unit should not be exposed directly to the sun, however, if this cannot beavoided, one can make sunshade to protect it from direct sunlight.

3) No water should collect around outdoor unit: The location of the outdoor unitshould be such that during rains, water is not collected around the unit. The large pondof water can drown the parts of the unit and destroy them. Even the small level of watercollected around outdoor unit for long time can corrode its body and eventually theinternal parts.

4) Dont install the outdoor unit on the tilted surface: One should avoid installing theoutdoor units on the tilted surfaces. The outdoor unit is quite heavy and if it placed inangular position, there will be unbalanced forces that would increase the vibrations ofthe unit, which may eventually result in total uprooting of the unit.

5) Installing the outdoor unit on the external wall: The outdoor unit can also behanged on the external wall on some angle supports. The angles can be fitted on thewall by using special bolts called anchor bolts. On these angles the outdoor unit can befitted easily and can be accessible conveniently. Make sure that the wall on which theoutdoor unit is being fitted is strong enough to bear its weight and vibrations. Installingthe outdoor unit on the wall is one of the best available options.

Steps for the Installation of the Outdoor Unit ofDuctless Split AC

1) First of all, bring the outdoor unit to the location where it has to be installed. This unitis quite heavy, so it should be handled carefully and there should be about two to threepeople for moving it.

2) Lift the unit to the place where it has to be installed. If the outdoor unit has to beinstalled on the angles fitted on the wall, make sure that the angles have been fitted


18/42

properly. Since the unit is too heavy, about three to five people may be needed for liftingit and it should be lifted carefully with proper coordination.

3) Next, the outdoor unit can be fitted at the suitable location. It is can be placed on therubber bushing and fitted with the anchor bolts to avoid vibrations or it can also be

placed directly on the flat rigid surface (since it is quite heavy the chances of itsvibrations are very less). The outdoor unit to be fitted on the wall can be fitted directly onthe angles by nut and bolts.

With this the installation of the outdoor unit is done. In the next article we shall see theinstallation of refrigerant tubing and gas charging.

Installation of the Refrigerant Tubing in Split

Air ConditionersIn the previous articles of this series on installation of the ductless split AC we saw theinstallation of the indoor unit and the outdoor unit. In this article we shall see installationof the refrigerant tubing, and electric connections.

In the previous articles of this series on installation of the ductless split AC we saw thefactors to be considered for selecting the location of the indoor and outdoor units andthe step-by-step installation of the indoor unit and the outdoor unit. In this article we

shall see the installation of the refrigerant tubing, and electric connections.

Installation of the Refrigerant Tubing

Installation of the Refrigerant TubingOnce the indoor and the outdoor units of the split air conditioner have been installed,the refrigerant tubing connecting the two units can be installed. The refrigerant tubing is
http://www.brighthub.com/engineering/mechanical/articles/45249.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45596.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45811.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45915.aspx?image=55489http://www.brighthub.com/engineering/mechanical/articles/45915.aspx?image=55488http://www.brighthub.com/engineering/mechanical/articles/45915.aspx?image=55487http://www.brighthub.com/engineering/mechanical/articles/45915.aspx?image=55489http://www.brighthub.com/engineering/mechanical/articles/45915.aspx?image=55488http://www.brighthub.com/engineering/mechanical/articles/45915.aspx?image=55487http://www.brighthub.com/engineering/mechanical/articles/45915.aspx?image=55489http://www.brighthub.com/engineering/mechanical/articles/45915.aspx?image=55488http://www.brighthub.com/engineering/mechanical/articles/45915.aspx?image=55487http://www.brighthub.com/engineering/mechanical/articles/45811.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45596.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45249.aspx


19/42

the flexible copper piping that can be bent easily by bending instruments. Variousconnections can also be made easily at the end of the copper tubing by using flaringtool. The copper tubing are connected to the indoor and the outdoor units by flare nutsand other flaring fittings using male and female connections. The copper tubing can alsobe connected to each other by brazing. The refrigerant tubing comes along with the new

split air conditioner, and you dont have to purchase the new one unless the distancebetween the indoor and outdoor units is too long.

There are two connections between the indoor and the outdoor units. The firstconnection carries refrigerant at low temperature from the outdoor unit to the indoor unitand the other one carrying return refrigerant at medium temperature from the indoor unitto the outdoor unit.

The refrigerant tubing is laid over long distance and in open atmosphere, which is atvery temperature. If the tubing is exposed directly to the sun, the refrigerant flowing fromthe outdoor unit to the indoor unit will get heated and loose all the refrigerating effect

before producing the cooling effect in the indoor unit. To prevent this loss of the coolingeffect, the tubing is covered with the insulation material. Similarly, the refrigeranttravelling through return tubing from indoor unit to outdoor unit is also at mediumtemperature and may get superheated when exposed directly to the atmosphere. Thiscan lead to the reduction in the compressor efficiency, and overall reduction in coolingeffect. To avoid this, the return tubing is also covered with the insulation material so thatthe refrigerant enters compressor at lowest possible temperature in gaseous state.

The insulation material is also accompanied with the new split AC. The material used forinsulation is foam which is in the form of the tube inside which the copper tubing can beeasily fitted. To make the fitting more rigid, the insulation tape is covered with sticky

tape though this may not be necessary all the times.

Connecting the Refrigerating Tubing to the Indoor Unit

Here are the steps for connecting refrigerating tubing to the indoor unit of split AC:

1) From the indoor unit of the split AC two copper tubing emerge which are passedthrough the hole made in the wall, these two tubing have flaring connections at theirends.

2) The distance between the indoor and outdoor unit is measured, and two copper

tubing of this length are cut.

3) On one of the ends of the these two tubing flaring connections are made forconnecting into the flare nut already available on the tubing emerging from the indoorunit. One can also directly connect the two newly cut tubing to the indoor unit tubing bybrazing without making flare connections. One end of each of the two tubing is nowconnected to the indoor unit.


20/42

4) Next, extend these tubing to the outdoor unit. On the way, you can provide support tothese tubing to the wall by using brackets so that they wont keep on hanging here andthere. This is to avoid the breakage of connections due to vibrations resulting in leakageof the refrigerant.

5) Before connecting the refrigerant tubing to the outdoor unit, it should be covered withthe insulation material, which is usually the foam tube.

Connecting Refrigerant Tubing to the Outdoor Unit

Here are steps for connecting the refrigerant tubing to the outdoor unit:

1) Make the flare connections at the two free ends of the two tubing using flaring tooland inserting the female flare nut.

2) Connect the nuts of each of the tubing to the connector provided outside the outdoor

unit and tighten the connection.

The indoor and outdoor units are now connected by the refrigerant tubing. The two unitscan now be connected together by the electric wiring which is finally connected to themain supply. Now the final process of gas charging and starting of the split airconditioner can be started.

Gas Charging in Split Air ConditionersIn the previous articles we was the factors affecting the location of indoor and outdoorunits of split AC, the installation of the indoor unit, the outdoor unit and the refrigeranttubing. In this article we shall see the final step of installation of split air conditioner, thegas charging.

In the previous articles we was thefactors affecting the location of the indoor andoutdoor units of split AC,the installation of the indoor unit,the outdoor unit andtherefrigerant tubing. In this article we shall see the final step of the installation of split airconditioner, the gas charging.

If the installation of the indoor unit, outdoor unit and the refrigerant tubing is doneproperly, the process of gas charging in the new split air conditioner is very simple. Infact in the new split air conditioners no process like gas charging is involved. In the newunits, the indoor and the outdoor units are prefilled with the gas.

When indoor unit is connected to the outdoor unit via refrigerant tubing, the tip of tubingoriginally attached to the indoor unit has to be opened, which leads to the leakage of
http://www.brighthub.com/engineering/mechanical/articles/45249.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45249.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45249.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45249.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45596.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45596.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45596.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45811.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45811.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45915.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45915.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45915.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45915.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45915.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45915.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45811.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45596.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45249.aspxhttp://www.brighthub.com/engineering/mechanical/articles/45249.aspx


21/42

refrigerant that comes with the unit prefilled from the factory. Thus this gas cannot beused in the split air conditioner for the cooling purposes.

Gas Charging from the Outdoor Unit

The outdoor unit is also prefilled with the refrigerant or the gas from the factory. Most ofthe gas is filled in the condenser coil at very high pressure. Since the gas is filled at highpressure sufficiently large quantity of gas can be filled in the condenser, which is goodenough to produce the desired cooling effect in the room.

Since the refrigerant is already present in the air conditioning system, we dont havecharge the extra gas, however, if the distance between the indoor and the outdoor unitsis large, some external gas charging may be necessary. The gas present within theoutdoor unit has to be released to the whole system including the refrigerant tubing andthe indoor unit. Thus in the new split unit there is no actual gas charging in real sense, itis only distributing the gas compressed in the outdoor unit to the whole air conditioning

system.

There are two valves located at the lower end of the outdoor unit, one for supplying thecompressed gas from the outdoor unit to the indoor unit and other one for receiving thereturn gas from the indoor unit. Initially, both the valves are closed. During gas chargingboth the valves are opened slowly. With this the refrigerant gets distributed in the wholeair conditioning system including the indoor unit, the outdoor unit and the refrigeranttubing.

Checking for the Gas Leakages

The gas charged into the system is like the life blood for the whole unit. Even slightleakages of the gas can hamper the performance of the system and it continuousleakage can render the unit useless. Further, even the cost of the gas is very high, so itsleakage will not only lead to the breakdown of the air conditioning system, but also highcosts of repairing. Hence it is vital to check right at the installation of the system thatthere are no leakages of the gas.

The leakages have to be mostly checked at the joints of the refrigerant tubing. Thereare four joints in the split air conditioner: two at the indoor unit and two at the outdoorunit, connecting the refrigerant tubing and the indoor and the outdoor units. Since the

gas is now present in the air conditioning system, it is at high pressure.

To check for the leakages soap solution is applied to the joints. If there are anyleakages, you will see the gas leaking in the form of the bubbles and if there are noleakages the soap solution remains stable.

If there is some gas leakage the connections have to be tightened. If the leakagedoesnt stops, the leakage point may have to be dismantled and reinstalled.


22/42

Starting the Air Conditioning System

Once the gas has been charged in the air conditioning system and it has been checkedfor the leakages, the system can now be started. It is assumed here that everything isgoes well with the installation. When the system is started you can feel the cool air

coming from the indoor unit within a minute or two.

You can adjust the position of the louvers of the indoor unit to evenly distribute the coolair inside the room or you can keep them at fix position to divert the cool air in particulardirection. You can also adjust the speed of the fan. If you dont need the cooling effect,you can keep the AC on fan mode. Most of the settings can be done from the remotecontrol.

Chapter 4: Central Air Conditioning Plants

Central air conditioning plants are used for applications like big hotels, large buildingshaving multiple floors, hospitals, etc, where very high cooling loads are required. Thearticle describes various possible arrangements of central air conditioning plants.

The central air conditioning plants or the systems are used when large buildings, hotels,theaters, airports, shopping malls etc are to be air conditioned completely. The window

and split air conditioners are used for single rooms or small office spaces. If the wholebuilding is to be cooled it is not economically viable to put window or split air conditionerin each and every room. Further, these small units cannot satisfactorily cool the largehalls, auditoriums, receptions areas etc.

In the central air conditioning systems there is a plant room where large compressor,condenser, thermostatic expansion valve and the evaporator are kept in the large plantroom. They perform all the functions as usual similar to a typical refrigeration system.However, all these parts are larger in size and have higher capacities. The compressoris of open reciprocating type with multiple cylinders and is cooled by the water just likethe automobile engine. The compressor and the condenser are of shell and tube type.

While in the small air conditioning system capillary is used as the expansion valve, inthe central air conditioning systems thermostatic expansion valve is used.

The chilled is passed via the ducts to all the rooms, halls and other spaces that are tobe air conditioned. Thus in all the rooms there is only the duct passing the chilled airand there are no individual cooling coils, and other parts of the refrigeration system inthe rooms. What is we get in each room is the completely silent and highly effective airconditions system in the room. Further, the amount of chilled air that is needed in the


23/42

room can be controlled by the openings depending on the total heat load inside theroom.

The central air conditioning systems are highly sophisticated applications of the airconditioning systems and many a times they tend to be complicated. It is due to this

reason that there are very few companies in the world that specialize in these systems.In the modern era of computerization a number of additional electronic utilities havebeen added to the central conditioning systems.

There are two types of central air conditioning plants or systems:

1)Direct expansion or DX central air conditioning plant: In this system the hugecompressor, and the condenser are housed in the plant room, while the expansionvalve and the evaporator or the cooling coil and the air handling unit are housed inseparate room. The cooling coil is fixed in the air handling unit, which also has large

blower housed in it. The blower sucks the hot return air from the room via ducts andblows it over the cooling coil. The cooled air is then supplied through various ducts andinto the spaces which are to be cooled. This type of system is useful for small buildings.

2)Chilled water central air conditioning plant:This type of system is more useful forlarge buildings comprising of a number of floors. It has the plant room where all theimportant units like the compressor, condenser, throttling valve and the evaporator arehoused. The evaporator is a shell and tube. On the tube side the Freon fluid passes atextremely low temperature, while on the shell side the brine solution is passed. Afterpassing through the evaporator, the brine solution gets chilled and is pumped to thevarious air handling units installed at different floors of the building. The air handling

units comprise the cooling coil through which the chilled brine flows, and the blower.The blower sucks hot return air from the room via ducts and blows it over the coolingcoil. The cool air is then supplied to the space to be cooled through the ducts. The brinesolution which has absorbed the room heat comes back to the evaporator, gets chilledand is again pumped back to the air handling unit.

To operate and maintain central air conditioning systems you need to have goodoperators, technicians and engineers. Proper preventative and breakdown maintenanceof these plants is vital.

Must Read

1) Direct Expansion or DX Type of Central Air Conditioning Plant

Direct Expansion (DX) Type of Central Air Conditioning Plant or System

There are two types of central air conditioning systems: Direct Expansion (DX) type ofcentral air condition plants and Chilled Water type of the central air conditioning plants.This article describes the DX central air conditioning system.
http://www.brighthub.com/engineering/mechanical/articles/50158.aspxhttp://www.brighthub.com/engineering/mechanical/articles/50158.aspxhttp://www.brighthub.com/engineering/mechanical/articles/50158.aspxhttp://www.brighthub.com/engineering/mechanical/articles/50160.aspxhttp://www.brighthub.com/engineering/mechanical/articles/50160.aspxhttp://www.brighthub.com/engineering/mechanical/articles/50160.aspxhttp://www.brighthub.com/engineering/mechanical/articles/50160.aspxhttp://www.brighthub.com/engineering/mechanical/articles/50158.aspxhttp://www.brighthub.com/engineering/mechanical/articles/50158.aspxhttp://www.brighthub.com/engineering/mechanical/articles/50158.aspxhttp://www.brighthub.com/engineering/mechanical/articles/50160.aspxhttp://www.brighthub.com/engineering/mechanical/articles/50158.aspx


24/42

Introduction

There are two types of central air conditioning systems: Direct Expansion (DX) type ofcentral air condition plants and Chilled Water type of the central air conditioning plants.In the DX system the air used for cooling the room or space is directly passed over the

cooling coil of therefrigerationplant. In case of the chilled water system the refrigerationsystem is used to first chill the water, which is then used to chill the air used for coolingthe rooms or spaces.

Both these systems have been discussed in details; this article discusses DX system,while the next one describes chilled water system.

Direct Expansion (DX) Type of Central AirConditioning Plant

In the direct expansion or DX types of air central conditioning plants the air used forcooling space is directly chilled by the refrigerant in the cooling coil of the air handlingunit. Since the air is cooled directly by the refrigerant the cooling efficiency of the DXplants is higher. However, it is not always feasible to carry the refrigerant piping to thelarge distances hence, direct expansion or the DX type of centralair conditioningsystemis usually used for cooling the small buildings or the rooms on the single floor.

There are three main compartments of the DX type of central conditioning systems(please refer the fig below):

DX Central Air Conditioning Plant

1) The Plant Room:The plant room comprises of the important parts of the refrigeration system, thecompressor and the condenser. The compressor can be either semi-hermetically sealedor open type. The semi-hermetically sealed compressors are cooled by the air, which isblown by the fan, while open type compressor is water cooled. The open compressorcan be driven directly by motor shaft by coupling or by the belt via pulley arrangement.
http://www.brighthub.com/guides/refrigeration.aspxhttp://www.brighthub.com/guides/refrigeration.aspxhttp://www.brighthub.com/guides/refrigeration.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/engineering/mechanical/articles/50158.aspx?image=56712http://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/refrigeration.aspx


25/42


26/42

a single floor. If there are largeair conditioningloads, then multiple direct expansionsystems can be installed. In such cases, when there is lesser heat load one of theplants can be shut down and the other can run at full load. The DX expansion systemruns more efficiently at higher loads. Even in case of the breakdown of the plants, theother plants can be used for the cooling purpose. The DX types of central air

conditioning plants are less popular than the chilled water type of central conditioningplants.

Image Courtesy and Reference

1) BasicRefrigerationand Air-conditioning by P N Ananthanarayanan, Tata McGraw-Hill Publishing Company Limited.

Chilled Water Central Air Conditioning

SystemsIn the previous article we saw DX type of central air conditioning plant, this articledescribes chilled water type of central air conditioner.

Chilled Water Central Air Conditioning Plants

The chilled water types of central air conditioning plants are installed in the place wherewhole large buildings, shopping mall, airport, hotel, etc, comprising of several floors areto be air conditioned. While in the direct expansion type of central air conditioning

plants, refrigerant is directly used to cool the room air; in the chilled water plants therefrigerant first chills the water, which in turn chills the room air.

In chilled water plants, the ordinary water or brine solution is chilled to very lowtemperatures of about 6 to 8 degree Celsius by therefrigerationplant. This chilled wateris pumped to various floors of the building and its different parts. In each of these partsthe air handling units are installed, which comprise of the cooling coil, blower and theducts. The chilled water flows through the cooling coil. The blower absorbs return airfrom the air conditioned rooms that are to be cooled via the ducts. This air passes overthe cooling coil and gets cooled and is then passed to the air conditioned space.

Chilled Central Air Conditioners
http://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/refrigeration.aspxhttp://www.brighthub.com/guides/refrigeration.aspxhttp://www.brighthub.com/guides/refrigeration.aspxhttp://www.brighthub.com/guides/refrigeration.aspxhttp://www.brighthub.com/guides/refrigeration.aspxhttp://www.brighthub.com/guides/refrigeration.aspxhttp://www.brighthub.com/guides/refrigeration.aspxhttp://www.brighthub.com/guides/refrigeration.aspxhttp://www.brighthub.com/guides/air-conditioning.aspx


27/42

Various Parts of the Chilled Water Air ConditioningPlant

All the important parts of the chilled waterair conditioningplant are shown in the abovefigure and described in detail below:

1) Central Air Conditioning Plant Room:

The plant room comprises of all the important components of the chilled water airconditioning plant. These include the compressor, condenser, thermostatic expansionvalve and the evaporator or the chiller. The compressor is of open type and can bedriven by the motor directly or by the belt via pulley arrangement connected to themotor. It is cooled by the water just like the automotive engine.

The condenser and the evaporator are of shell and tube type. The condenser is cooledby the water, with water flowing along the shell side and refrigerant along the tubeside.The thermostatic expansionvalveis operated automatically by the solenoid valve.

The evaporator is also called as the chiller, because it chills the water. If the water flowsalong the shell side and refrigerant on the tube side, it is called as the dry expansiontype of chiller. If the water flows along tube side and the refrigerant along the shell side,it is called as the flooded chiller. The water chilled in the chiller is pumped to variousparts of the building that are to be air conditioned. It enters the air handling unit, coolsthe air in cooling coil, absorbs the heat and returns back to the plant room to get chilledagain. The amount of water passing into the chiller is controlled by the flow switch.

In the central air conditioning plant room all the components, the compressor,condenser, thermostatic expansion valve, and the chiller are assembled in the structural

steel framework making a complete compact refrigeration plant, known as the chillerpackage. Piping required to connect these parts is also enclosed in this unit making ahighly compact central air conditioning plant.
http://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/valve.aspxhttp://www.brighthub.com/guides/valve.aspxhttp://www.brighthub.com/guides/valve.aspxhttp://www.brighthub.com/engineering/mechanical/articles/50160.aspx?image=56721http://www.brighthub.com/engineering/mechanical/articles/50160.aspx?image=56720http://www.brighthub.com/engineering/mechanical/articles/50160.aspx?image=56719http://www.brighthub.com/engineering/mechanical/articles/50160.aspx?image=56721http://www.brighthub.com/engineering/mechanical/articles/50160.aspx?image=56720http://www.brighthub.com/engineering/mechanical/articles/50160.aspx?image=56719http://www.brighthub.com/engineering/mechanical/articles/50160.aspx?image=56721http://www.brighthub.com/engineering/mechanical/articles/50160.aspx?image=56720http://www.brighthub.com/engineering/mechanical/articles/50160.aspx?image=56719http://www.brighthub.com/guides/valve.aspxhttp://www.brighthub.com/guides/air-conditioning.aspx


28/42

2) Air Handling Unit Rooms:

The air handling units are installed in the various parts of the building that are to be airconditioned, in the place called air handling unit rooms. The air handling units compriseof the cooling coil, air filter, the blower and the supply and return air ducts. The chilled

water flows through the cooling coil. The blower absorbs the return hot air from the airconditioned space and blows it over the cooling coil thus cooling the air. This cooled airpasses over the air filter and is passed by the supply air ducts into the space which is tobe air conditioned. The air handling unit and the ducts passing through it are insulatedto reduce the loss of the cooling effect.

3) Air Conditioned Rooms:

These are the rooms or spaces that are to be air conditioned. These can be residentialor hotel rooms, halls, shops, offices, complete theater, various parts of the airport etc. At

the top of these rooms the supply and the return air ducts are laid. The supply air ductssupply the cool air to the room via one set of the diffusers, while the return air ductsabsorbs the hot return air from the room by another set of the diffusers. The hot returnair enters the air handling unit, gets cooled and again enters the room via supply duct toproduceair conditioningeffect.

4) Cooling Tower:

The cooling tower is used to cool the water that absorbs heat from the compressor andthe condenser. When water flows through these components some water getsevaporated, to make up this loss some water is also added in the cooling tower. The

cooling tower is of evaporative type. Here the water is cooled by the atmospheric airand is re-circulated through the compressor and the condenser.

Image Courtesy and Reference

1) BasicRefrigerationand Air-conditioning by P N Ananthanarayanan, Tata McGraw-Hill Publishing Company Limited.

2)http://www.peoplesgasdelivery.com/business/DisplayESource.aspx?type=PA&page=PA

_15

Comparison of DX and Chilled Water CentralAir Conditioning Plants
http://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/refrigeration.aspxhttp://www.brighthub.com/guides/refrigeration.aspxhttp://www.brighthub.com/guides/refrigeration.aspxhttp://www.brighthub.com/guides/refrigeration.aspxhttp://www.brighthub.com/guides/air-conditioning.aspx


29/42

The Direct Expansion (DX) and Chilled Water central air conditioning plants are bothused at different places depending on the applications and size of the place to be airconditioned. Let us see the comparison of DX and chilled water central air conditioningplants.

IntroductionThe Direct Expansion (DX) and Chilled Water centralair conditioningplants are bothused at different places depending on the applications and size of the place to be airconditioned. Both of them have their own advantages and disadvantages. Let us seethe comparison of DX and chilled water centralair conditioningplants.

1) DX Central Air Conditioning Plants are moreEfficient

In the DX type of central air conditioning plants the air used for cooling the room isdirectly chilled by the refrigerant in the cooling coil of the air handling unit. Due to thisheat transfer process is more efficient, since there is no middle agency involved for theheat transfer resulting in higher cooling efficiency.

In case of the chilled water system, the cooling effect from the refrigerant is firsttransferred to the chilled water, which is then used to chill the air used for cooling theroom. There is some loss of the cooling effect when it is being transferred from therefrigerant to the chilled water and from there to the air due to which the chilled watersystems have lesser cooling efficiency. The chilled water acts as the secondary mediumfor cooling the room air in air handling unit.

Further, the chilled water has to flow long distance along the whole building. On its wayit tends to get heated due to friction of flow and also due to surrounding heat absorption.The chilled water also has to be pumped by the pump, which adds more heat to it. Thusas the chilled water flows from the chiller to the air handling unit and again back to thechiller, apart from the heat from air, it also absorbs lots of additional heat, which leads tohigh increase in its temperature. The chiller has to remove this additional heat from thewater due to which its efficiency decreases or rather additional power is required toremove this additional heat. In the DX type of central air conditioning plants therefrigerant travels only through the small distances and there is no pump involved so theadditional heat absorption is less, which makes the DX plants even more efficient.

2) The Chilled Water Plants can be used for the LargeMulti Storey Buildings
http://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspx


30/42

In the direct expansion types of the central air conditioning plant, the refrigerant like R22flows through the wholeair conditioning systemincluding the air handling unit. Whenthe refrigerant flows in the refrigeration piping there is lots of drop in its pressure. Due tothis the length of the refrigeration tubing and the distance between the condenser andthe air handling unit should be kept minimum possible.

If the air handling unit is kept at the height more than the condenser, the loss inpressure is pronounced since refrigerant travelling from the condenser to the airhandling unit is in liquid state. As the distance between the air handling unit and thecondenser increases the loss in pressure also increases. At certain point the lossesmay be so high that the refrigerant may not be able to reach the air handling unit,leading to complete failure of the system. At the larger height difference there is also oilreturn problem from the refrigerant to the compressor.

Due to these reasons, in direct expansion type of the central air conditioning plant thereis limitation on the distance between the condenser and the air handling unit. The

distance between the two cannot be too high. This limits the application of the directexpansion type of central air conditioning systems to the small buildings or a number ofrooms on the single floor. In such cases the plant room and air handling room and therooms to be cooled are located on the same floor. The height difference between thecondenser and the air handling units has to be quite reasonable so that they canfunction well.

One of the solutions to increase the capacity of the DX systems can be to increase thenumber of air handling units on upper floors. But with this will be additional number of

joints in the refrigerant tubing from which there will be higher chances of leakage ofhighly expensive refrigerant. This leads to too many operational and maintenance

problems.

One may think that we can employ compressor of very high capacity to increase therefrigerant pressure, but this will lead to highly excessive capital and running costs ofthe plant. This is because we will have to install the compressor of capacity much higherthan needed.

Thus the direct expansion types of the air conditioning plants can be used only forsmaller buildings or various rooms on the same floor.

There are no pressure loss problems in the chilled water system. In this system chilled

water is pumped by the pump at very high pressure, which is good enough to carry it tovarious floors of the multi storey building. The losses in the pressure of water areaccommodated by the sufficient capacity of the pump, which has low capital andrunning cost. Further, the water doesnt carry any oil so there are no oil return problems.

In case of the chilled water system the compressor, condenser, expansionvalveandthe chiller are all kept at the same level in the single plant room. There is no problem assuch of the height difference between the condenser and the air handling unit since the
http://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/valve.aspxhttp://www.brighthub.com/guides/valve.aspxhttp://www.brighthub.com/guides/valve.aspxhttp://www.brighthub.com/guides/valve.aspxhttp://www.brighthub.com/guides/air-conditioning.aspx


31/42

refrigerant does not travels to the air handling unit. The flow of the refrigerant is limitedto the chiller plant. The water chilled in the chilled flows to the various air handling unitskept on different floors of the building. The whole arrangement and the structure of thechilled water type of central air conditioning plant makes it more suitable for cooling thelarge multi storey buildings and even for very long distances along the same floor level.

This makes the chilled water central air conditioners more popular than the directexpansion type ones.

Reference

1) Basic Refrigeration and Air-conditioning by P N Ananthanarayanan, Tata McGraw-Hill Publishing Company Limited.

Air Handling Units or Fan Coil Units

As the name suggests air handling unit is the box type of unit that handles the room air.This article describes various parts of the air handling unit, its working and types.

What are Air Handling Units or Fan Coil Units?

The air handling units are very important parts of the central air conditioning plants,packaged air conditioning plants and also the roof mounted splitairconditioningsystems. As the name suggests air handling unit is the box type of unit thathandles the room air. It comprises of the cooling coil over which the hot return air fromthe room flows, gets cooled and flows back to the room to cool it. The circulation of the

air is carried out by the blower. The filter in the air handling unit enables cleaning of theair. The air handling units are also called as fan coil units in case of roof mounted splitAC units, since they comprise of the fan and the cooling coil.

The air handling units are installed at the different places in the building to be airconditioned. They are connected to the cool air supply and return air ducts which arelaid in all the rooms to be cooled. In case of the central air conditioning plants the airhandling units are installed on the floor, while in case of the split air conditioners, theyare mounted on the roof inside the room above the false ceiling. In case of packagedunits they can be installed on the floor or the roof.

The various parts of the air handling unit and their working are discussed in detailsbelow:

Air Handling Units
http://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspxhttp://www.brighthub.com/guides/air-conditioning.aspx


32/42

1) Box Enclosure:

All the parts of the air handling unit are enclosed in the box type of enclosure. Thisensures compactness of the unit and protection of all the components inside it. Thewhole box is insulated to prevent the loss of heat from the unit.

2) Cooling Coil:The cooling is one of the most important parts of the air handling units. It is made up ofcopper tubing of several turns and covered with the fins to increase the heat transferefficiency of the cooling coil. In direct expansion (DX) type of the centralairconditioningplants the refrigerant flows though the cooling coil, which also acts as theevaporator of the plant. In case of the chilled water system the chilled water from thechiller flows through the cooling coil. In packaged and the splitair conditionersalso therefrigerant flows directly through the cooling coil, thus acting as the evaporator of thesystem.

The hot return air from the room flows over the cooling and gets cooled. This air issupplied to various rooms via the ducts. The flow of chilled water or the refrigerant tothe cooling coil is controlled by the solenoid valve.

3) Ducts:

The air handling is connected to the supply air and return air ducts. The supply air ductsupplies the cool air from the air handling unit to various rooms, while the return air

supplies hot return air from various rooms back to the air handling unit. There is onemain supply duct that bifurcates into various small ducting that are laid in all the roomsthat are to be cooled. The return ducts from all the rooms also

zobdet el takyeef

Documents