Automobile air conditioning through engine exhaust gases

8/20/2019 Automobile air conditioning through engine exhaust gases

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Project Report onVapor Absorption Refrigeration System UsingEngine Exhaust Gases


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ABSTRACT

An automobile air conditioning system generally works on vapor compression cycle

comprising of compressor, condenser, expansion device and evaporator.The objective of projectis to use vapor absorption system instead of vapor compression system having

ammonia as the refrigerant and water as the absorbent. Th e re fr ig er at io n sy st em

comprises of a generator, a drier, a condenser, an evaporator, an absorber. The improvementis characterized in utilizing the residual heat from the exhaust pipe of an engine by helically

winding a coil tube around the main portion of the exhaust pipe so that the

liquidized refrigerant ammonia from the gener ator will flow through and be heatedinto a mixture of the vapor and water and enter into the generator for a process of separation.

Then, the vapor enters into the condenser via a capillary tube and from there enters into the

evaporator for a process of vaporization. The vapor from the evaporator will then go

to the absorber and reenter the generator after it is mixed with water which isreturned from the segregator after being processed. !hereby, a cooling circulation

for this system is therefore completed.

"y implementing this absorption system, the compressor is eliminated there byreducing the power consumption of the system. This results in higher overall efficiency and less

fuel consumption of the engine. #urther an analysis is made between vaporcompression and vapor absorption system and various parameters are studied.The main aim of

the project is to study implementation of vapour absorption system for air conditioning and make

a working model.

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Submitted By:

Sarthak Agarwal -50

Prantik Biswas - 51

Kapil Saraswat - 52

Umang Bhatia - 5


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INDEX OF CONTENTS

Sl. No. Title Pg. No.

Abstract $

%ist of #igures &

$ 'ntroduction (

) *eed +

& Absorption refrigeration ystem -

&.$ !orking rinciple -

&.) /perating tages -

( %ist of 0omponents 1

+ 0omparision between 203 and 2A3 $+

- Advantages $-

4 0onclusion $4

2


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2. LIST OF FIGURES

Figure No: Name Pg. No.

$ chematic of the ammonia5water

absorption refrigeration system -

) 6vaporator 1

& 0ondensor 1

( Absorber 7

+ 3eceiver 8rier 7

- chematic of 3eceiver 8rier $9

- ump $9

4 :lass cloth tape $$

1 'nsulation foam tube $)

7 :lobe 2alves $)

$9 ;eating 0oil $&

$$ 8rier $&

$) :enerator $(

$& 0onnecting tubes $(

3


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. INTRODUCTION

The vapour absorption refrigeration system is one of the oldest methods of producing refrigerating effect. The

principle of vapour absorption was first discovered by


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2. NEED

An automobile engine utilizes only about &+= of available energy and rests are lost to cooling and exhaust system.

'f one is adding conventional air conditioning system to automobile, it further utilizes about += of the total energy.Therefore automobile becomes costlier, uneconomical and less efficient. Additional of conventional air conditioner

in car also decreases the life of engine and increases the fuel consumption. #or very small cars compressor needs &

to ( bhp , a significant ratio of the power output. >eeping these problems in mind, a car air conditioning system is

proposed using exhaust gases. The advantages of this system over conventional airconditioning system are that it

does not affect designed efficiency life and fuel consumption of engine. And hence makes the running of the

engine efficient and economical. Thus to have the more economical air conditioning and more efficient engine in

the automobile the need of this system arises.

!


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!. ABSORPTION REFRIGERATION S"STE#

!. $or%i&g Pri&'i(le

The underlying principle is the ?ractical 2apor Absorption ystem@ that uses a :enerator, instead of

compressor i.e. used in vapor compression systemB. This :enerator requires a ;eat ource to generate Ammoniavapors from Aqueous Ammonia olution received from Absorber. The above heat requirement is served by theexhaust heat of the engine .ome power is also required to run the ump, which is used to raise the pressure

of Aqueous Ammonia olution as well as to transmit it from Absorber to :enerator. As the pump consumes very

less amount of power in comparison to 0ompressor, it is quite comfortable to drive it from battery power ordirectly from crankshaft .Csing the above setup, we can relieve the crankshaft from excess load of compressor

Dthis will help in decreasing the fuel requirement of engine. Thus, increases the fuel efficiency.

o, without using any other equipment or source of energy besides the vehicle itself, it is possible to introduce this

airconditioning system in existing automobilesEvehicles. Also it uses Ammonia as refrigerant, which do not affectthe ozone layer as well as it does not contribute to the greenhouse effect.

!.2 O(eratio&al Stage)

#ig $F 2apor Absorption 3efrigeration 0ycle

"


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Stage *2:

• The low pressure ammonia vapor leaving the evaporator enters the absorber where it is

absorbed by the cold water in the absorber.

• The water has the ability to absorb very large quantity of ammonia vapor and the solution thus formed, is

known as aquaammonia.

Stage 2*!:

• The strong solution thus formed in the absorber is pumped to the generator by the liquid pump to increase

the pressure of the solution up to $9 bar.

Stage !*+:

• The strong solution of ammonia is heated by some external source, in our system by the exhaust heat of

automobile.

• 8uring the heating process the ammonia vapor is driven off the solution at high pressure leaving behind

the hot weak ammonia solution in the generator.

Stage +*,:

• The weak ammonia solution flows back to the absorber at low pressure after passing through the pressure

reducing valve.

Stage -*:

• The high pressure vapor from the generator is condensed in the condenser to high pressure liquid

ammonia.

Stage */:

•

The condensed liquid ammonia from the condenser is stored in a vessel known as receiver valve, fromwhere it is supplied to the evaporator through the expansion valve.

Stage /*0:

• The liquid ammonia is passed to the expansion valve in which its high pressure and temperature is

reduced at a controlled rate after passing through it.

Stage 0*:

• The liquid vapor ammonia at low pressure and temperature is evaporated and changed into vapor

refrigerant. 'n evaporator, the liquid vapor ammonia absorbs its latent heat of vaporization from the

medium to be cooled.

#


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+. LIST OF CO#PONENTS

+. E1a(orator

#ig ) 6vaporator

62A/3AT/3 is a device used to turn or allow to turnB the liquid form of a refrigerant into its gaseous form. Anevaporator is used in an air conditioning system to allow the compressed cooling refrigerant ammoniaB to

evaporate from liquid to gas while absorbing heat in the process. 't is installed in the low pressure side of the cycle.

+.2 Co&e&)er

#ig & 0ondensor

$he con%enser is a %e&ice use% to change the high'pressure refrigerant &apor to a(i)ui%* +t is mounte% in front of the engine,s ra%iator- an% it (oo.s &ery simi(ar to ara%iator* $he &apor is con%ense% to a (i)ui% because of the high pressure that is %ri&ingin it- an% this generates a great %ea( of heat* $he heat is then in turn remo&e% from thecon%enser by air /o0ing through the con%enser on the outsi%e*


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+t is insta((e% in the high pressure si%e of the cyc(e 0hose function is to remo&e the heatof the hot &apor refrigerant %ischarge%- 0hich consists of heat absorbe% by thee&aporator *$he heat from the hot &apor refrigerant in a con%enser is remo&e% rst bytransferring it to the 0a(( of con%enser tubes an% then from the tubes to the con%ensingor coo(ing me%ium 0hich may 0ater- air or combination of both*

+.! A3)or3er

#ig ( Absorber Absorber is the part of the system where vapor ammonia at low pressure and weak solution from the generator

comes through pressure reducing valve and get accumulated.

;ere the vapor ammonia gets dissolved into the water as per the solubility ratio of water and ammonia. This waterand ammonia vapor solution is known as aqua ammonia solution or strong solution which is pumped to the

generator at high pressure where it is heated from some external source of heat. Thus, Ammonia vapor gets

evaporated and the cycle continues.

+.+ Re'ei1er*Drier

#ig + 3eceive 8rier

The receiverdrier is used on the high side of systems that use a thermal expansion valve. This type of metering

valve requires liquid refrigerant. To ensure that the valve gets liquid refrigerant, a receiver is used .The primary

function of the receiverdrier is to separate gas and liquid. The secondary purpose is to remove moisture and filterout dirt.


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#ig -. chematic of 3eceiver 8rier

The receiverdrier usually has a sight glass in the top. This sight glass is often used to charge the system. Cnder

normal operating conditions, vapor bubbles should not be visible in the sight glass. This is a small reservoir vessel

for the liquid refrigerant, and removes any moisture that may have leaked into the refrigerant.


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umps fall into three major groupsF direct lift, displacement, and gravity pumps .Their names describe the method

for moving a fluid. ump converts the mechanical energy from a motor to energy of a moving fluidD some of the

energy goes into kinetic energy of fluid motion, and some into potential energy, represented by a fluid pressure or by lifting the fluid against gravity to a higher level

+.- Gla)) Clot4 Ta(e

#ig 1 :lass cloth tape

:lass cloth tube is an electrical insulator and the heat conductor i.e. it enables the heat to be transmitted but insulatethe system electrically. 't is made from high grade heat resistant glass cloth coated with special silicone backing.

0haracteristicsF

•

;ighly conformable and easy to install

• 2ery flexible accommodating angles and turns

• Aggressive adhesive system

• 3emoves easily without leaving residue

• ;igh tensile strength and abrasion resistant

• 3epositionable

• 6xcellent performance in temperatures up to +99G# )-9G0B

• 0an be singlesided or doublesided

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+. I&)ulatio& Foam Tu3e

#ig7 'nsulation foam tape

'nsulation is a product that blocks transfer of heat, thus helps in maintaining the desired temperature by obstructing

the flow of heat.

C4ara'teri)ti'):

•%ow thermal conductivity > valueB makes it highly efficient and effective in the insulation of cooling orheating systems.

• The thermal blister close cell structure forms as impermeable layer which is in itself a good vapor barrier.

• 't is suitable for application within the temperature range of (9G0 to $)+G0.

• The material has been specially compounded to selfextinguishing in nature.

• 't is 0#0, asbestos, chlorine and fiber free and does not cause skin allergy.

• 't is inert to most chemical agent and neutral to pipe metals.

• The extreme flexibility of the materials makes installation fast, easy and economical

+./ Glo3e 5al1e)

#ig $9 :lobe 2alves

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A glo3e 1al1e is a type of valve used for regulating flow in a pipeline, consisting of a movable disktype element

and a stationary ring seat in a generally spherical body.

+.0 6eati&g Coil 7Ni'4rome8

#ig $$ ;eating coil

Ni'4rome is a nonmagnetic alloy of nickel, chromium, and often iron, usually used as a resistance wire. atented

in $79+, it is the oldest documented form of resistance heating alloy. A common alloy is 19= nickel and )9=chromium, by mass, but there are many others to accommodate various applications. 't is silverygrey in colour, is

corrosionresistant, and has a high melting point of about $(99 G0. 8ue to its relatively high electrical resistivity

and resistance to oxidation at high temperatures, it is widely used in electric heating elements, such as in hair

dryers, electric ovens, soldering iron, toasters, and even electronic cigarettes. Typically, *ichrome is wound in coilsto a certain electrical resistance, and current is passed through to produce heat.

+.9 Drier

#ig $) 8rier

#ilterdriers play a pivotal role in the operation of air conditioning and refrigeration systems. At

the heart of the unit is the desiccant held in its cylindrical metal container. As important asthe filterdrier is, many actually do not understand how it works.

The word desiccate means to dry out completely and a desiccant is a material or substance that accomplishes themoisture removal.


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+. Ge&erator

#ig.$& :enerator

• 't is a kind of heat exchanger.

• 0ollects ;eat from 6xhaust and 0oolant to vaporize Ammonia from strong solution of Aq. Ammonia.

• upplies 2aporized Ammonia to 0ondenser.

+.2 Co&&e'tio& Tu3e)

#ig $( 0onnection tubes

1


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,. Com(ari)o& o 5a(or A3)or(tio& Rerigeratio& o1er 5a(or Com(re))io&

Rerigeratio&

8 #et4o o 'om(re))io& o t4e rerigera&t

/ne of the most important parts of any air conditioning cycle is the compression of the refrigerant since all the

further operations depend on it. 'n the vapor compression air conditioning system the compression of therefrigerant is done by compressor which can be of reciprocating, rotating or centrifugal type. 'n the vapor

absorption air conditioning system, the compression of the refrigerant is done by absorption of the refrigerant bythe absorbent. As the refrigerant is absorbed, it gets converted from the vapor state to liquid state so its volumereduces.

28 Po;er 'o&)um(tio& e1i'e)

'n the vapor compression cycle the compressor is the major power consuming device while in the vapor

absorption cycle the pump used for pumping refrigerantabsorbent solution is the major power consuming device.

!8 T4e amou&t o (o;er re


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-. A1a&tage)

• Cses 6ngine heat as source of energy hence enhances the efficiency of engine.

•


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. Co&'lu)io&

As per our analysis and references, we have found that, it is possible to design a air conditioning system using

engine heat based on 2apor Absorption 3efrigeration ystem. Also from the 6nvironmental point of view this

system is 6cofriendly as it involves the use of Ammonia as a refrigerant which is a natural gas and is not

responsible for /H/*6 layer 8epletion. #urthermore, it also saves the power of engine as it replaces the

compressor by the four components i.e. Absorber, ump, :enerator I ressure 3educing 2alve out of which onlythe pump consumes some power that too is very feeble as compared to that of the 0ompressor, and thus helps in

saving of fuel. Also this system can be employed to commercial heavy vehicles including those which are

involved in the transportation of refrigerated products, as this system can easily provide the refrigerationEair

conditioning of cabin as per the requirements by using the exhaust heat of the vehicleJs engine which is in

abundance in such vehiclesB thus will not add any additional engine to run the airconditioningErefrigerating unit in

vehicle and hence reduces the operational cost.

All in all, it can be a very well and economical asset for the automobile and can completely change the scenario of

air conditioning systems.

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Automobile air conditioning through engine exhaust gases

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