DESIGN AND FABRICATION OF CONDENSER FOR A

ROOM AIR CONDITIONING SYSTEM

A PROJECT REPORT

Submitted by

G.SATHISHKUMAR 42609114081

V.SATISH 42609114082

R.SEETHARAM 42609114083

A.SELVAN 42609114084

In partial fulfillment for the design and fabrication project work

of

BACHELOR OF ENGINEERING

in

MECHANICAL ENGINEERING

SRI RAMANUJAR ENGINEERING COLLEGE

VANDALUR, CHENNAI 600 048

ANNA UNIVERSITY: CHENNAI 600 025

APRIL 2012

BONAFIDE CERTIFICATE

Certified that this project report “DESIGN AND FABRICATION OF

CONDENSER FOR A ROOM AIR CONDITIONING SYSTEM ”

is the bonafide work of

G.SATHISHKUMAR 42609114081

V.SATISH 42609114082

R.SEETHARAM 42609114083

A.SELVAN 42609114084

Who carried out the project work under my supervision

SIGNATURE SIGNATURE

Prof. s. Raja Rao Mr. M.RAJAMOHAN

HEAD OF THE DEPARTMENT SUPERVISOR,ASSISTANT PROFESSOR.

DEPARTMENT OF MECHANICAL ENGINEERING DEPARTMENT OF MECHANICAL

SRI RAMANAJUR ENGINEERING COLLEGE SRI RAMANAJUR ENGINEERING COLLEGE

VANDALUR CHENNAI 600048 VANDALUR CHENNAI 600048

Submitted for the project review and viva-voce examination held on………………….

INTERNAL EXAMINER EXTERNAL EXAMINER

ABSTRACT

The work deals with the design and fabrication of condenser for room air-

conditioning system which is used to condense vapour into liquid. The hot high

pressure refrigerant gas is condensed to a sub cooled liquid by transferring its heat

either to water or air. The condensation takes by two ways: 1.Air cooled

condenser, 2.Water cooled condenser. The heat transfer co-efficient of air cooled

condenser is lower than the water cooled condenser. Hence the fabrication work is

concerned with the water cooled condenser which increases the heat transfer co-

efficient ratio. So that heat generation is controlled to some extent and also reduces

the power usages.

1.Introduction

An Air Conditioning condenser works by exchanging the inside heat and building

the outside air to a cool and pleasant air. All this is based on a simple refrigeration

principle. Condenser coil plays a vital role in the entire refrigeration process. It is

made of aluminum and surrounds the compressor of the AC unit.

What generally takes place inside the outside unit is the change of state of the

refrigerant which happens inside the AC unit. The refrigerant which changes its

state to a gas in the indoor coil flows outside where the high pressure compresses

the gas inside the compressors. After this the hot gas moves from the compressor

and travels through the tubing which is present in the condenser coil.

1.1Types of air conditioner condenser

AC condenser units are grouped according to how it rejects the heat to the medium

(surround air). Here are a few condensers units.

1.1.1Air cooled condenser

1.1.2Earth cooled condenser (Geothermal Heat Pumps)

1.1.3Water cooled condenser

1.1.4Combination of air and water cooled condenser (Evaporative condensers)

Air cooled condensers are mostly used in residential air conditioner units and

commercial air conditioning unit.

1.1.1The Air Cooled Condenser

The air conditioner parts that are located beside residential are an air cooled

condenser.

Air cooled condenser use outdoor air as a place to reject the heat absorbs by the air

conditioner units. The condenser also has parts that help with heat reject.

Here are some of the condenser parts:

1.1.1.1Condenser fan blade

1.1.1.2Condenser motor

1.1.1.3Condenser coils

1.1.1.4Air conditioner compressor is within the condenser unit, but it does not

help with heat rejection!

The condenser fan is mounted with the air cooled condenser. The condenser fan

primary purpose is to increase condenser unit’s capacity to reject heat.

Air cooled condenser come into two types:

1.1.1.1.1Fin and tube condensers

1.1.1.1.2Plate condensers

This is the basic representation of an air cooled condensing system.

And the parts are illustrated in it.

1.1.2The Water Cooled Condensers

The water cooled condensers reject the heat absorbs by air conditioner system to

the water. The water has to be clean, noncorrosive, and at certain temperature. This

water has to be treating to prevent pitting corrosive, algae, scale, chalky, and

mineral deposits.

Even though, water cooled condenser require regular maintenance, it is more

efficient than air cooled condenser, and it operates at much lower condensing

temperature.

Types of water cooled condensers:

1.1.2.1Tube in tube

1.1.2.2Shell and coil

1.1.2.3Shell and tube

What are air conditioner condensers?

Air conditioner condensers are a heat exchanger device; it has a similar operation

principle to the evaporator.

The condenser rejects heat from the air conditioner units to surrounding air

(medium). While the evaporator absorbed heat from space that needs to be cool. In

our case, it is from indoor air.

The condenser units take in high-pressure, high temperature refrigerant gas from

the compressor and turn it into high-pressure, high temperature liquid refrigerant.

How does an ac condenser change refrigerant gas to liquid refrigerant? Here how it

does that.

Air conditioner condensing unit work by turning vapor refrigerant to liquid

refrigerant. There are three important steps that should happen to the refrigerant as

it passes through the condensing unit.

First Step: The hot vapor coming from the compressor must be de-superheated to

the vapor saturation point. De-superheated? De-superheated is removing a sensible

heat from the refrigerant, lower the refrigerant temperature.

Second Step: In the middle of the condenser, there should is mixture of gas/liquid

refrigerant. This is where the refrigerant vapor should change to 100 percent liquid

refrigerant.

Third Step: The refrigerant temperature should be lowered below the liquid

saturation point, subcooled.

2. COMPRESSOR :.

An air conditioning system has several parts that assist in the cooling of air. These

parts are the compressor, the condenser, and the evaporator. An air conditioning

compressor is the part of the air conditioning system that compresses cool, low

pressure gas into a hot, high pressure gas. The compression of this gas is the first

part in a multi-step process that helps keep the area cool. Though the compressor is

an important part of the air conditioning system, if any one of these parts fail, the

unit will fail.

A properly working air conditioner starts with low pressure gas traveling into the

air conditioning compressor. The compressor compresses the gas into a high

pressure gas with a higher temperature. This is why it is called an air conditioning

compressor. At this point, the gas must be cooled down. This is when it travels to

the condenser.

In the condenser, the gas is cooled into a liquid still under high pressure. After this,

it travels to the evaporator. In the evaporator, the liquid is squeezed through a

small hole and into tubing. In this tubing, the liquid uses the heat from the room to

be cooled in order to turn back into a gas. The low-pressure, cool gas is then

transported back to the air conditioning compressor to start the journey all over

again.

The Air Conditioning Compressor Itself - on residential units the A/C compressor

motor is most often a hermetic motor-compressor combined in a single sealed unit

like the Carrier™ unit shown.

2.1.How does an air conditioning compressor motor work?

The job of the compressor/condenser unit is to recompress warm refrigerant gas

(pulled from the indoor air handler cooling coil) back to a liquid refrigerant that

can be returned to the indoor cooling coil once again. When the room thermostat

calls for cooling, both the indoor blower or air handler and the outdoor

compressor/condenser begin to work. Control circuits and a contactor relay turn on

the outside compressor/condenser motor and its outdoor cooling fan as well.

The air conditioning or heat pump compressor compresses the incoming refrigerant

to a high pressure gas and moves that gas into the condensing coil described just

below. Typically a piston moves up and down inside of a cylinder inside the

compressor motor, drawing in refrigerant gas on the down stroke of the piston, and

compressing the refrigerant gas on the up stroke of the piston. (Some refrigeration

compressors such as those made by Frigidaire™ used a rotary compressor design

that we found durable and powerful enough to lead us to salvage and re-use these

motors for other purposes.

The refrigerant gas leaves the compressor at high pressure and at high temperature

(since compressing a gas will raise its temperature). In most air conditioning or

heat pump compressors, a piston moves up and down to draw in and then compress

refrigerant gas, moving refrigerant vapor from the incoming low side to the

outgoing high side of the compressor.

The refrigerant gas leaving the compressor (and entering the condensing coil) will

contain both heat that the refrigerant absorbed at the evaporator coil (heat from air

in living space of the building), and additional heat produced at the compressor by

the process of compressing the gas. The refrigerant gas is thus heat laden with

sensible heat (heat that we can measure) from the living area and compressor heat

from the compressor motor.

Low side and high side refer to the low-pressure and high-pressure areas of the air

conditioning equipment and are defined in more detail at SEER RATINGS &

OTHER DEFINITIONS where we also explain sensible heat and other air

conditioning terms.

2.2.Refrigeration and Air Conditioning Theory:

In an air conditioning system, pressure is used to change (increase) the

vaporization point (state change from liquid to gas) or condensation point (state

change from gas to liquid) of the refrigerant. On the A/C system's high side (high

refrigerant gas pressure side of the system), the condensation point must be some

temperature above ambient outdoor air temperature (if air is being used to cool the

condensing coil) or condensation of the refrigerant gas back to a liquid will not

occur.

2.3.Creation of high side & low side in a refrigeration system:

The restriction in refrigerant flow created by the thermostatic expansion valve

(TEV, discussed below) [or on many systems simpler CAPILLARY TUBES]

located close to the evaporator coil (cooling coil) allows the compressor to raise

the pressure and increase the temperature at which the refrigerant (coolant) will

change state (from liquid to gas in the cooling coil, and from gas back to liquid in

the condensing coil).This restriction in refrigerant flow at the TEV is what allows

the compressor a pressure difference between the high side and low sides of the

system. Evaporator coil is defined at A/C COMPONENTS and discussed further at

AIR HANDLER / BLOWER UNITS. TEVs, AEVs, manual and adjustable

expansion valves, and float valves are discussed at THERMOSTATIC

EXPANSION VALVES. Capillary tubes for metering refrigerant are discussed

separately at CAPILLARY TUBES.

Room air conditioners such as window or through wall mounted units, and some

other refrigeration equipment such as a home refrigerator, use a capillary tube (cap

tube) instead of a thermostatic expansion valve. A cap tube is simply a small

diameter tube used to meter liquid refrigerant from the "high" side of the system

into the cooling coil (the start of the low side of the system). Unlike a TEV, a cap

tube is fixed in output and cannot be adjusted.

2.4.State change of refrigerant gas to liquid:

The state change of the air conditioning refrigerant from a high pressure high

temperature gas back to a liquid occurs inside the outdoor condensing coil. This

state change (gas to liquid) releases energy in the form of heat which is blown into

outdoor air (or transferred into water). Note: the compressor has to produce high

enough output pressure that the gas moving through the condensing coil moves at a

good velocity in order to scrub the entire condensing coil tubing surface and thus

transfer its heat out through the condensing coil tubing into ambient air (or water).

2.5.State change of refrigerant liquid to gas:

The state change from a liquid refrigerant to a low pressure gas occurs in the

indoor evaporator or cooling coil, absorbing energy in the form of heat (the heat in

indoor air being blow across the evaporator coil), thus moving heat from the indoor

air into the refrigerant gas in the system. For example, R12 changes state at -21

degF; R22 changes state at -41 degF.

So summing up this theory and practice of air conditioning, the job of the air

conditioning compressor is to reduce pressure on the low side (cooling side) of the

system and to increase pressure on the high side (warming side) of the system.

These pressure differences move refrigerant through the system and enable it to

change states from liquid to gas (at the TEV and in the evaporator coil) and from

gas to liquid (in the condensing coil). This process moves heat (absorbed by the

evaporator coil inside the cooling or refrigerated area) through the condenser coil

and into outside air (or water).

2.6.Special oil used in air conditioning & refrigeration compressor motors

Air conditioning and refrigeration compressors use a special oil which does not

react with the refrigerant liquid or gas in the system. The oil may mix and travel

with the refrigerant however, and some cooling systems are designed for deliberate

movement of the compressor oil in order to lubricate some parts such as refrigerant

metering valves or compressor valves.

3. OBJECTIVES

3.1To meet the high price rice of electricity by designing efficient condenser

for home air conditioning system.

3.2To increase the cooling power of air conditioning system.

3.3 To develop on eco-friendly air conditioning system.

4.WORKPLAN

Designing, fabrication and assembling

Testing and evaluation

Selection of condenser type

Information gathering

Conclusion

4.1 INFORMATION GATHIERING:

4.1.1. Required information is gathered from book and journal.

4.1.2. Collected information is analyzed.

4.2 SELECTION OF CONDENSOR TYPE:

4.2.1. After gathering the information and analyzing the suitable type of condenser

is selected for the fabrication of cooling unit.

4.2.2. Liquid cooled condenser is been used in the cooling unit.

4.3 DESIGNING FABRICATING AND ASSEMBLING:

Standard Features—All Condensers

Condensers consist of condenser coil(s), housing, propeller fan(s) direct-driven by

individual fan motor(s), electrical controls and mounting legs. Air-cooled

condensers provide positive refrigerant head pressure control to the Precision

Cooling indoor unit by adjusting heat rejection capacity . Various methods are

employed to match indoor unit type, minimum outdoor design ambient

and maximum sound requirements.

PARTS OF CONDENSING UNIT:

1. Condensing unit fan motor BLADE ASSEMBLY.

2. Condenser FAN MOTOR.

3. Fan motor MOUNTING BRACKET.

4. CAPACITOR to assist motors in running more efficiently.

5. CONTACTOR (the relay that allows the 230 VAC to turn on the motors.

6. CONDENSER COILS (refrigerant runs through the tubes and ambient air is

pulled through the fins to cool the hot gas).

7. SUCTION LINE VALVE that closes the refrigerant flow and/or gives a port

in which to attach the pressure gages and hoses.

8. LIQUID LINE VALVE to close off the high pressure and/or provides an

access port for pressure measurement.

9. COMPRESSOR MOUNTING BASE .

10.COMPRESSOR motor and pump. The newest compressor is the SCROLL, a

giant step forward in efficiency.

BLADE ASSEMBLY:

Aluminum propeller fan blades are secured to a corrosion-protected steel hub. Fan

guards are heavy gauge, close-meshed steel wire with corrosion resistant PVC

finish rated to pass a 675-hour salt spray test . Fans are secured to the fan motor

shaft by a keyed hub and dual setscrews. Fan diameter is 26"

(660mm) or less. The fans are factory-balanced and run before shipment.

This is a very soft aluminum material and will bend

very easily and thus become unusable. Take great care when

handling it especially during removal of it or the motor.

Air loads onto each blade as it turns and thereby creates pressure.

If just one blade is different from the whole, then the load is

off-balance and the wobble will appear in varying degrees depending

on the difference of the shape of the one blade. Think of the tires

and wheels on the car. Out of balance wobble and bounce is very similar.

If the blades are out of balance the bearings in the motor will wear

excessively and will shorten the life of that motor considerably.

Do so by first sanding the shaft of the motor it is bolted onto. Clean

this shaft very well and then oil the shaft and locking assembly with a

light penetrating oil. Use an adjustable wrench (one without teeth) on

the flat side (between the blade hub and the motor) of the shaft to hold

it firmly. Then wiggle off the blade assembly. Hopefully it will not

require more drastic measures. Don't ever beat on the end of the shaft

or deface it on the end with wrenches or you will really have difficulty

sliding the blade assembly off it. Remember too, with the new one as you

replace it, don't bend it by pushing on or pulling on the blades. Clean

and sand the shaft until the new blade slide on easily.

Fan speed control utilizes a wave-chopper control to vary the air volume over the

condenser coil, based on refrigerant head pressure. The fan motor next to the

electrical panel (two fans on 6-fan and 8-fan models) is a single-phase, permanent

split capacitor motor with motor speed adjusted in response to refrigerant pressure.

The balance of fans on multi-fan units cycle on ambient thermostats.

The control system provides refrigerant head pressure control for outdoor ambients

as low as -20°F (-28.9 °C).

Motor Run Capacitors:

This is one of those complicated little devices that

electrically operates with most of these motors to make

it run a lot more efficiently. You will most likely not

have the instrument to test it and it is not reasonable here

to explain it's makeup and details of function.

Suction Line and Liquid Line Service Valves:

Figure 7 is the suction line service valve and is the one for the checking of the

"freon"

(refrigerant) inside the SUCTION or low side of the refrigerant cycle.

To use this port, you need a set of refrigerant hoses, manifold and

gauges. Here you would remove the small cap (1/4 inch flare or

grommet sealed) and screw onto it the hose to test the pressure inside.

When you remove the cap, there should be no pressure escaping since

it has a Schrader valve in the port to hold back the pressure.

This is like the bicycle air valve. Or, it may have another cap near it when

removed will reveal a stem device that must be screwed down a bit to release the

pressure into the gauge port while your hoses are attached.

This expanded view shows the details of its design

Figure 8 is for the checking of the refrigerant inside the LIQUID or high

side of the system and is probably identical to the one for the suction line,

but will be smaller. This one can be really dangerous until you are familiar

with its characteristics. It is best that you not use this port until you have

watched someone else do it and have "hands-on" experience.

The refrigerant in this side is in the liquid state and under a much higher

pressure. It can give you frost bite or worse before you can get away. It

may be at a temperature of minus 30 degrees or less and is not to be handled

without prior knowledge. However, you must use the service port if you wish

to check the high side pressure (and you need to know what it is if you are

trouble-shooting a problem).

If you do use this port, be sure to put it on the HIGH SIDE GAUGE. Its

pressure may exceed the low side gauge capability and damage the

gauge. Also, make sure the hose you use is of new or like-new quality. The

pressure could stress an old hose and it may burst. A professional

replaces his or her hoses every year and buys only good quality.

Condenser Fan Motor:

The condenser’s fan motor is a continuous air-over design equipped with rain

shield and permanently sealed bearing. Die-formed, galvanized steel supports are

used for rigid mounting of the motor.

These types of motors are usually rather small in horsepower (1/10th to

3/4). They are most often sealed on the ends and sides to keep out water,

etc. and if they point upward with the shaft, then a rain shield is added

to help keep the water out of the bearing. Often these bearing are also

sealed and cannot even be oiled. More often there is no real bearing, but

rather is a bushing. This type surely needs oiling more often. Usually once

a year is fine. If it is a heat pump type unit that runs all year, then it

may require more oiling.

If it "oils", then there is provided a way. Usually, a passageway from the

bearing or bushing extends to the side of the motor at each end--one for

each bearing. It will have a metal or plastic plug and will rarely have a

spring-loaded cap except on some really old motors. Simply remove the plug

and apply the oil. Apply only the equivalent of five "eye dropper" drops per

oil port on each bearing and no more. Too much oil will overflow into the

WINDINGS and soften or weaken the enamel coating and the motor may short

out in a few years. Replace the plug. Always replace the plug to keep out

any dirt. Dirt is a killer for bearings so use clean oil and keep the tip

of the applicator clean.

These motors run pretty hot to the touch. Normal length of comfortable

touch of a motor that had been running might be about one or two seconds before

discomfort. This is normal. Anything less than this amount of time would

indicate an overheating problem. The bearings might be bad or the motor might

be internally damaged electrically or mechanically. It might have a bad

capacitor (located in the control panel and discussed later). It might just

be so dirty, that it overheats. Clean it. Sometimes, the condenser coils are

so clogged that the air is excessively hot coming over the motor. Keep these

clean also. These motors have an internal thermostat that switches them off

if they get too hot and then when it cools it will reset again. So a motor

might run for a while, shut off, and run again. A compressor will not run

long without the fan running. It also will shut off, cool, and run again.

Motor Starting Contactors:

A contactor is sometimes called relay or starter. Its function is to interrupt the

incoming 230 volts and wait until the call from the thermostat to close its contacts

and thus turn on the condenser fan and compressor. The thermostat, upon demand,

will send 24 volts (usually) to the magnetic coil of this contactor and thus pull

down on the assembly for the contacts to close and the 230 volts then rushes on to

the motor, etc.

One of the more important things about the contactor is the contact points.

The are usually made of some very soft alloy ranging from gold to cadmium.

Sometimes the contact points will become so pitted and out of original shape

that they are not making good contact. THIS IS OF PARAMOUNT CONCERN.

This is the device that sends the correct voltage and current to the fan motor

and the compressor.

A compressor is an important and very expensive part of the cooling system. In

fact, it is the heart of the system. It will suffer greatly if the contact points do not

supply instantly and appropriately the right voltage and current to it.

Compressor Mounting Hardware:

All compressors have mounting legs and grommets where the mounting bolts

secure them firmly to the base of the condensing unit. This keeps them floating on

the rubber of the grommets for quiet operation and also will prevent them from

moving within the condenser and damaging anything else.

Motor Mounting Bracket:

This is one of thousands of different looking brackets. It's a

pretty simple part of the equipment. Notice that there are bolts to hold the motor

tightly in this bracket. Others may also have a "stop" for the motor at the bottom of

the bracket--something like an offset arm to catch the motor at the bottom to stop it

in an exact place. Some are a bit complicated with numerous screws holding it

together, but just watch the way it comes apart and put it back the same way. If you

don't get the same physical size motor for replacement, you will have difficulty or

an impossibility when you try fitting the bracket on the new motor. It is the same

thing when you buy a new bracket. Try to get the exact one or its intended

replacement.

Condenser Coils:

The condenser coils are tubes to carry the refrigerant through so it can be cooled.

The fins on the tubes make it happen with great efficiency in that they have

become so well designed that they transfer a lot of heat very rapidly. They are soft

aluminum and must be keep free of damage and must be kept clean for them to

work well.

Manufactured coils are constructed of copper tubes in a staggered tube pattern.

Tubes are expanded into continuous, corrugated aluminum fins. The fins have full-

depth fin collars completely covering the copper tubes, which are connected to

heavy wall Type “L” headers. Inlet coil connector tubes pass through relieved

holes in the tube sheet for maximum resistance to piping strain and vibration. Coils

are either single circuit or dual circuit, depending on the application. The hot-gas

and liquid lines are spun shut at the factory and include a factory-installed Schrader

valve. Coils are fac- tory leak-tested at a minimum of 300 psig (2068kPag),

dehydrated, then filled and sealed with a nitro- gen holding charge for shipment.

DIFFERENT STAGES IN CONDENSER OF AC

THREE STEPS OCCURING IN A CONDENSER:

First Step: The hot vapor coming from the compressor must be de-superheated to

the vapor saturation point. De-superheated? De-superheated is removing a sensible

heat from the refrigerant, lower the refrigerant temperature.

Second Step: In the middle of the condenser, there should is mixture of gas/liquid

refrigerant. This is where the refrigerant vapor should change to 100 percent liquid

refrigerant.

Third Step: The refrigerant temperature should be lowered below the liquid

saturation point, subcooled

ZONES OCCURING:

SUBCOOLING ZONE:

In refrigeration, subcooling is the process by which a saturated liquid refrigerant is

cooled below the saturation temperature, forcing it to change its phase completely.

The resulting fluid is called a subcooled liquid and is the convenient state in which

refrigerants may undergo the remaining stages of a refrigeration cycle [1] . Normally,

a refrigeration system has a subcooling stage, allowing technicians to be certain

that the quality, in which the refrigerant reaches the next step on the cycle, is the

desired one. Subcooling may take place in heat exchangers and outside them.

Being both similar and inverse processes, subcooling and superheating are

important to determine stability and well-functioning of a refrigeration system.

TWO PHASE ZONE:

In the middle, there exist mixture of gas/liquid refrigerant. This is where the

refrigerant vapor should change to 100 percent liquid refrigerant.In this stag the

liquid is in an optimum phase and undergoing some changes there .

SUPERHEATING ZONE:

In the system’s evaporator, conversion of liquid to vapor involves adding heat to

the liquid at its boiling temperature, commonly referred to as the saturation

temperature. After all of the refrigerant has boiled to a vapor, any additional

temperature increase above the boiling point is called superheat .Finding suction

line superheat requires finding the suction pressure and two temperatures — the

evaporator boiling temperature at a given pressure and the temperature of the

refrigerant at the outlet of the evaporator on the suction line, commonly referred to

as the superheated phase.

6. TESTIN G AND EVALUATION:

Cooling is the process of removing heat from one area, where it is not wanted, to

an area where it not makes a difference. For the refrigeration process to work heat

has to flow from one area to another.

Here are some step to show how heat will be transfer from AC evaporator coils to

AC condensing unit.

1. Indoor heat transfer to refrigerant in evaporator coils

2. Compressor move heat to condenser units

3. Air conditioner condenser rejects heat and the process start again

In this discussion, the air conditioner condensers will transfer heat to air (not

water). For heat to flow one of the area has to be at a higher temperature. This is

because heat always flows from a high intensity to a low intensity.

The air conditioner condensers reject heat from the refrigeration system absorbed

at the evaporator and also heat of compression from the compressor. The

condenser contains refrigerant that must reject its heat to the outside medium (air

that surrounds the condenser). Therefore, the refrigerant temperature in the

condenser units must be higher than the surrounding air.

I will explain how air conditioner condensing unit work from PH charts.

The condenser units receive the hot vapor refrigerant after it leaves the compressor

through the short refrigeration line between the compressor and the condenser unit.

This refrigerant line has known as the hot gas line or discharge line.

Point 2 on the pH diagram showed the hot vapor from the compressor is forced

into the top of the condenser coils. The vapor refrigerant is being pushed at high

speed and high temperature to the condenser units.

The vapor does not corresponding to the saturation pressure/temperature

relationship because the vapor contains superheat added by the evaporator and the

heat of compression process. This process is shown between points 2 to 3.

The vapor entering the condenser is so hot compared to the surrounding air that a

heat exchange begins to occur immediately after the vapor leaves the discharge

area of the compressor. Generally, the air will be 90-105°F lower than the

superheated vapor leaving the compressor.

The first heat exchange removes sensible heat from the superheated vapor bringing

the refrigerant vapor to the saturation point, point 2 to 3 on the pH chart.

As the refrigerant vapor continues through the condenser latent heat is removed.

This process is shown between points 3 and 4. The removal of latent heat causes a

change of state to take place.

The vapor will begins to change to liquid from this point on until it reaches a point

nears the end of the condenser units where the entire vapor has changed to liquid.

This is known as the saturated liquid point, point 4 on the pH chart.

As the air conditioner refrigerant flows through the last few rows of the condenser

units additional sensible heat is removed, lowering the refrigerant temperature

below its liquid saturation point. This called subcooling and represented by the line

from point 4 to 5 on the pH chart.

There must be enough air flowing across the AC condenser, for vapor refrigerant

to change to liquid. The air flowing across the condenser unit has to be correct.

This airflow has to be at low enough temperature, so it could absorb heat from the

condenser unit.

The entire vapor refrigerant has to turn liquid before it leaves the condenser units.

And these steps have been proven sincerely and thus found that the condenser

developed meets the required scope.

7. CONCLUTION:

We conclude that the project made by us will be used to cool a room in an efficient

way and will meet the price rise in electrical sector in an economical way and will

be environmental friendly.

The design and fabrication of condenser for a home air conditioning system along

with its setup is used to cool a room as mentioned.

8. REFERANCES:

1. Refrigeration and air conditioning book by C P Arora/ 2000,1981 Tata

mcgraw-hill publications/ New Delhi.

2. Engineering thermo dynamics book by p k nag.

3. Engineering thermo dynamics book by vijayaragavan.