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LPG REFRIGERATOR

CHAPTER 1

REFRIGERATION

1.1 INTRODUCTION

The term ‘refrigeration’ in a broad sense is used for the process of removing heat

(i.e. cooling) from a substance. It also includes the process of reducing and maintaining

the temperature of a body below the general temperature of its surroundings. In other

words, the refrigeration means a continued extraction of heat from a body, whose

temperature is already below the temperature of its surroundings. For example, if some

space (say in cold storage) is to be kept at - from cold body and delivers to a hot body.

The substance which works in a heat pump to extract heat from a cold body and to

deliver it to a hot body is called refrigerant. When people hear the word refrigeration they

immediately think of the refrigerator in their kitchen. However there are actually quite a

few 2 ºC, we must continuously extract heat which flows into it due to leakage through

the walls and also the heat, which is brought into it with the articles stored after the

temperature is one reduced to -2 ºC. Thus in a refrigerator, heat is virtually being pumped

from a lower temperature to a higher temperature. According to second law of

thermodynamics, this process can only be performed with the aid of some external work.

It is thus obvious, that supply of power (say electrical motor) is regularly required to

drive a refrigerator. Theoretically, the refrigerator is a reversed heat engine, or a heat

pump which pumps heat different kinds of refrigeration out three and they each have their

own methods of functioning. One particular type of refrigeration is industrial

refrigeration. This type of refrigeration is typically used for cold storage, food processing,

and chemical processing. The equipment is very large and made of industrial stainless

that must maintain a constant and steady temperature at all times. Temperatures that are

too high or too low may spoil certain goods or ruin them. As a result industrial

refrigeration is especially important maintaining temperature is as well. Since

temperature is so important into industrial refrigeration companies offering this service

must pay attention at all times to the temperature of the industrial refrigerators.steel.

Industrial refrigeration, which frequently uses ammonia refrigeration to maintain

DEPARTMENT OF MECHANICAL ENGINEERING KLS VDRIT, HALIYAL

LPG REFRIGERATOR

temperature, is necessary for computer, foodstuffs, blood, vaccines, and quite a few other

goods.

1.2 HISTORY OF REFRIGERATION

The refrigeration system is known to the man, since the middle nineteenth

century. The scientist, of the time, developed a few stray machines to achieve some

pleasure. But it paved the way by inviting the attention ohine by the end of nineteenth

century for the refrigeration jobs. But with the advent of efficient rotary f scientist for

proper studies and research. They were able to build a reasonably reliable mac

compressors and gas turbines, the science of refrigeration reached its present height.

Hebrews, Greeks, and Romans placed large amounts of snow into storage pits dug into

the ground and insulated with wood and straw. The ancient Egyptians filled earthen jars

with boiled water and put them their roofs, thus exposing the jars to the night’s cool air.

In India, evaporating cooling was employed. When a liquid vaporises rapidly, it expands

quickly. The rising molecules of vapour abruptly increase their kinetic energy and this

increase is drawn from the immediate surroundings of the vapour. These surroundings are

therefore cooled. The intermediate stage in the history of cooling foods was to add

chemicals like sodium nitrate or potassium nitrate to water causing the temperature to

fall. Cooling wine via above method was recorded in 1550, as were the words “to

refrigerate”.

Cooling drinks came into vogue by 1600 in France. Instead of cooling water at

night, people rotate long-necked bottles in water in which saltpetre had been dissolved.

This solution could be used to temperature. Brewing was the first activity in the northern

states to use mechanical refrigeration extensively, beginning with an absorption machine

used by S. Liebmann’s Sons Brewing Company in Brooklyn, New York in 1870.

commercial refrigeration was primarily directed at breweries in the 1870 and 1891,

nearly every brewery was equipped with refrigerating machines. Natural ice supply

became an industry unto itself. By 1879, there were 35 commercial ice plants in America,

more than 200 a decade later, and 2,000 by 1909.


LPG REFRIGERATOR

No pond was safe from scraping for ice production, not even Thoreau’s Walden

Pond, where 1,000 tons of ice was extracted each day in 1847. However, as time went on,

ice, as a refrigeration agent, became health problem. Says Bern Nagengast, co-author of

Heat and Cold: Mastering the Great Indoors (published by the American Society of

Heating, Refrigeration and Air-conditioning Engineers), “Good sources were harder and

harder to find. By the 1890’s, natural ice became a problem because of produce very low

temperature and to make ice. By the end of the 17th century, iced liquors and frozen

juices were popular in French society. The first known artificial refrigeration was

demonstrated by William Cullen at the University of Glasow in 1748. Beginning in the

1840, refrigerated cars were used to transport milk and butter. By 1860, refrigerated

transport was limited to mostly seafood and dairy products. The refrigerated railroad car

was patented by J.B.Sutherland of Detroit, Michigan in 1867. He designed an insulated

car with ice bunkers in each end. Air came in on the top, passed through the bunkers, and

circulated through the car by gravity, controlled by the use of hanging flaps that created

differences in airpollution and sewage dumping.” Signs of a problem were first evident in

the brewing industry. Soon provided the solution: ice, mechanically manufactured, and

giving birth to mechanical refrigeration. Carl (Paul Gottfried) von Linde in 1895 set up a

large scale plant for the production of liquid air. Six years later the meatpacking and dairy

industries followed with their complaints. Refrigeration technology he developed a

method for liquid air separating pure liquid oxygen from that resulted in widespread

industrial conversion to processes utilizing oxygen (e.g. in steel manufacture).

1.3 TYPES OF REFRIGERATION The difference types of refrigeration systems are given below.

Cyclic Refrigeration

In the cyclic process of refrigeration the heat is removed from the low temperature

reservoir and is thrown to high temperature. As per the second law of thermodynamics

the natural flow of heat is from the high temperature to low temperature reservoir. In the

cyclic refrigeration process since the flow of heat is reversed, the external work has to be

done on the system.


LPG REFRIGERATOR

The cyclic process of refrigeration is also reverse of the thermodynamic power cycle or

Carnot cycle in which the heat flows from high temperature reservoir to low temperature

reservoir; hence the cycle of refrigeration is also called as Reversed Carnot Cycle.

There are two types of cyclic process of refrigeration:

Vapour cycle and

Gas cycle.

The vapour cycle is classified into

Vapour compression cycle and vapour absorption cycle.

Vapour Compression Cycle

In a vapour compression system, an evaporator and a gas-liquid separator are received in

a common casing, so that the gas-liquid separator and the of the liquid phase refrigerant

from the atmosphere to reduce the heat evaporator are placed close to each other. Thus, it

is possible to limit heart absorption loss upon discharge of the refrigerant from the gas-

liquid separator. Also, it is possible to reduce pressure loss in refrigerant passage between

the gas-liquid separator and the evaporator.

Vapour Absorption Cycle Before the development of the vapour compression

system of refrigeration, vapour absorption system was very widely used. The vapour

compression system replaced vapour absorption system because it has high coefficient

performance (COP). The vapour absorption system requires very less amount of

electricity but large amount of heat; hence it can be used very effectively in industries

where very large stocks of excessive stem are available. In such cases there is not only

effective utilization of steam, but also lots of savings in electricity costs.

Gas Cycle Just as the vapour are used for cooling in the vapour compression cycle

and vapour absorption cycle, the gas is used cooling in gas refrigeration cycle. When the

gas is throttled from very high pressure to lower pressure in throttling valve, its

temperature reduces suddenly while its enthalpy remains constant. This principle is in gas

refrigeration system. In the system instead of using Freon or ammonia as the refrigerant,

the gas is used as the refrigerant.


LPG REFRIGERATOR

Throughout the cycle there are no phase changes of the gas, which are observed in the

liquid refrigerant. Air is the most commonly used gas, also called as refrigerant in this

case, in the gas refrigeration cycles.

Non Cyclic Refrigeration

In these methods, refrigeration can be accomplished by melting ice or by dry ice. These

methods are used for small-scale refrigeration such as in laboratories and workshops, or

in portable coolers.

Thermoelectric Refrigeration

A refrigeration effect can also be achieved without using any moving parts by simply

passing a small current through a closed circuit made up of two dissimilar materials. This

effect is called Peltier effect, and a refrigerator that works on this principle is called a

thermoelectric refrigerator.

Magnetic Refrigeration

Magnetic refrigeration is a cooling technology based on the magneto caloric effect. This

technique can be used to attain extremely low temperatures (well below 1K), as well as

the ranges used in common refrigerators, depending on the design of the system.

Other Methods

Other methods of refrigeration include the air cycle machine used in aircraft; the vortex

tube used for spot cooling, when compressed air is available; and thermo acoustic

refrigeration using sound waves in a pressurised gas to drive heat transfer and heat

exchange.


LPG REFRIGERATOR

1.4 UNITS OF REFRIGERATION

Domestic and commercial refrigerators may be rated in kj/s, or Btu/h of cooling.

Commercial refrigerators in the US are in tons of refrigeration, but elsewhere in kw. One

ton of refrigeration capacity can freeze one short ton of water at 0 ºC (32 ºF) in 24 hours.

Latent heat of ice (i.e. heat of fusion) = 333.55 kj/kg ≈ 144 Btu/lb One short ton = 2000lb

Heat extracted = (2000)*(144)/24 hr = 288000 Btu/24 hr = 12000 Btu/hr = 200 Btu/min 1 tonne

of refrigeration = 200 Btu/min = 3.517 kj/s = 3.517 kwThe practical unit of refrigeration is

expressed in terms of ‘tonne of refrigeration’ (briefly written as TR). A tonne of

refrigeration is defined as the amount of refrigeration effect produced by the uniform

melting of one tonne (1000 kg) of ice from and 0 ºC in 24 hours. Since the latent heat of

ice is 335 kj/kg, therefore one tonne of refrigeration, 1 TR = 1000 * 335 kj in 24 hours =

(1000) * (335) / (24) * (60) = 232.6 kj/min In actual practice, one tonne of refrigeration is

taken as equivalent to 210 kj/min or 3.5 kw (i.e. 3.5 kj/s).

1.5 COEFFICIENT OF PERFORMANCE OF A REFRIGERATOR

The coefficient of performance (briefly written as C.O.P.) is the ratio of heat

extracted in the refrigerator to the work done on the refrigerant. It is also known as

theoretical coefficient of performance. Mathematically, Theoretically C.O.P. = Q/W

Where Q = Amount of heat extracted in the refrigerator ( or the amount of refrigeration

effect produced, or the capacity of a refrigerator), and W = Amount of work done.

1.6 APPLICATIONS


LPG REFRIGERATOR

Food processing, preservation and distribution

Storage of Raw Fruits and Vegetables

Fish

poultry

Dairy Products

o Ice cream

o Butter

o Cheese

o Buttermilk

o Beverages

o Candy

o Processing and distribution of frozen food

Chemical and process industries

Separating of gases

Condensation of gases

Dehumidification of Air

Storage as liquid at low pressure

Cooling for preservation

Special application of refrigeration

Cold Treatment of Metals

Medical

Ice Skating Rinks

Construction

Desalination of water

Ice manufacturer

It is also widely used for the cooling of storage chambers in which perishable

food, drinks and medicines are stored.

The refrigeration also has wide applications in sub-marine ships, rockets and

aircrafts.


LPG REFRIGERATOR

CHAPTER 2

REFRIGERATION PROCESS

2.1 REFRIGERATOR

Refrigerator keeps things cold because of the nature of the heat. Thermodynamics

essentially starts that if a cold object is placed to a next to a hot object, the cold object

will become warmer and the hot object will become cooler. A refrigerator does not cool

items by lowering their original temperature; instead, an evaporating gas called a

refrigerant draws heat away, leaving the surrounding area much colder. Refrigerators and

air conditioners both work on the principle of cooling through evaporation. A

refrigerator consists of two storage compartment – one for frozen items and the other for

items through the entire system is pure ammonia, which evaporates at -27 ºF. this system

is closed, which means nothing is lost or added while it is operating. Because liquid

ammonia is a powerful chemical, a leaking refrigerator should be repaired or replaced

immediately. The refrigeration process begins requiring refrigeration but no freezing.

These compartments are surrounded by a series of heat-exchanging pipes. Near the

bottom of the refrigerator unit is a heavy metal device called a compressor. The

compressor is powered by an electric motor. More heat-exchanging pipes are coiled

behind the refrigerator. Running with the compressor. Ammonia compressed until it

becomes very hot from the increased pressure. This heated gas flows through the coils

behind the refrigerator, which allows excess heat to be released into the surrounding air.

This is why users sometimes fill warm air circulating around the fridge. Eventually the

ammonia cools down to the point where it becomes a liquid. This liquid form of ammonia

is then forced through a device called an expansion valve or capillary tube. Essentially,

the expansion valve has a small opening or the capillary tube has a very small diameter of

copper tube that the liquid ammonia is turned into a very cold, fast-moving mist,

evaporating as it travels through the coils in the freezer. As the evaporating ammonia gas

absorbs more heat, its temperature rises. Coils surroundings the lower refrigerator

compartment are not as compact. The cool ammonia still draws heat from the warmer

objects in the fridge, but not as much as the freezer section. The ammonia gas is drawn


LPG REFRIGERATOR

back into the compressor, where the entire cycle of pressurization, cooling and

evaporation begins anew.

2.2 REFRIGERATION CYCLE

The refrigeration cycle uses a fluid, a called a refrigerant, to move heat from one

place to other. We will begin with the cool, liquid refrigerant entering the indoor coil,

operating as the evaporating during cooling. As the name implies, refrigerant in the

evaporator “evaporator”. Upon entering the evaporator, the liquid refrigerant’s

temperature is between 40 and 50 ºF and without changing its temperature, it absorbs heat

as it changes state from a liquid to a vapour. The heat comes from the warm, moist room

air blown across the evaporator coil. As it passes over the cool coil, it gives up some of

its heat and moisture may condense from it. The cooler, drier room air is re-circulated by

a blower into the space to be cooled. The vapour refrigerant now moves into the

compressor, which is basically a pump that raises the pressure so it will move through the

system. The increased pressure from the compressor causes the temperature of the

refrigerant to rise. As it leaves the compressor, the refrigerant is a hot vapour, roughly

120 to 140 º F. It now flows into the refrigerant-to-water heat exchanger, operating as the

condenser during the cooling. As it condenses, it gives up heat to the loop, which is

circulated by a pumpas the refrigerant leaves the condenser, it is cooler, but still under

pressure provided by the compressor. It then reaches the expansion valve or capillary

tube. That the high pressure refrigerant to “flash” through becoming a lower pressure,

cooled liquid. When pressure is reduced, as with spraying an aerosol can or a fire

extinguisher, it cools. The cycle is complete as the cool, liquid refrigerant re-enters

evaporator to pick up room heat.

2.3 HOW REFRIGERATOR WORKS

In the summertime, have you ever gotten out of a swimming pool and then felt

very cold standing in the sun? That’s because the water on your skin is evaporating. The

air carries off the water vapour, and with it being taken away from your skin. This is

similar to what happens inside older refrigerators. Instead of eater, through, the

refrigerator uses chemicals to do the cooling. There are two things that need to be known


LPG REFRIGERATOR

for refrigeration. 1. 2. A gas cools on expansion. When you have two things that are

difference temperature that touch or are near each other, the hotter surface cools and the

colder surface warms up. This is a law of physics called the Second Law of

Thermodynamics.

2.4 TYPES OF DOMESTIC REFRIGERATOR

There are two types of domestic refrigerator. 1. Single door fresh food refrigerator 2.

Double-door refrigerator-freezer Most domestic refrigerator are of two types – either a

single door fresh food refrigerator or a two-door refrigerator-freezer combination, with

the freezer compartment on the top portion of the cabinet, or a vertically split cabinet

(side-byside), with the freezer compartment on the left side of the cabinet. They are

completely self-contained units and are easy to install. Most refrigerators use R-22

refrigerant, normally maintaining temperatures of 0 ºF in the freezer compartment and

about 35 ºF to 45 ºF in the refrigerator compartment.

Fig. 2.4(a) Single door Fig. 2.4(b) Double door


LPG REFRIGERATOR

2.5 TEMPERATURTE ZONE AND RATING

Some refrigerators are now divided into four zones to store different types of

food: » » » » -18 ºC (0 ºF) (freezer) 0 ºC (32 ºF) (meats) 5 ºC (49 ºF) (refrigerator) 10 ºC

(50 ºF) (vegetables) The capacity of a refrigerator is measured in either litres or cubic feet

(US). Typically the volume of a combined fridge-freezer is split to 100 litres (3.53 cubic

feet) for the freezer and 140 litres (4.94 cubic feet) for the refrigerator, although these

values are highly variable. Temperature settings for refrigerator and freezer compartments

are often given arbitrary numbers (for example, 1 through 9, warmest to coldest) by

manufacturers, but generally 2 to 8 ºC (36 to 46 ºF) is idle for the refrigerator

compartment and -18 ºC (0 ºF) for the freezer. Some refrigerators require a certain

external temperature 16 ºC (60 ºF) to run properly. Thus can be an issue when placing a

refrigerator in an unfinished area such as a garage.

2.6 REFRIGERANT

Refrigeration application Short description Typical HFCs usedDomestic

Refrigeration Commercial Appliances used for keeping food in dwelling units. Holding

and displaying frozen and fresh HFC-134a R 404A, R 507, Refrigeration food in retail

outlets HFC-234a Food processing and cold Equipment to preserve, process and store

R410A, storage food from its source to the wholesale and cooling Industrial Refrigeration

Large equipment, typically 25 kW to 30 MW, used for chemical processing, cold storage,

food processing and district Transport refrigeration heating and cooling Equipment to

preserve and store goods, primarily foodstuffs, during transport by road, rail, air and sea

R410A, R407C, HFC-134A R407C,R 507, HFC-134a HFC-134a, R404A, R-507.


LPG REFRIGERATOR

2.7 VAPOUR COMPRESSION CYCLE

2.7.1 Introduction

The vapour compression cycle is the mostly widely used method of refrigeration in the

modern application. Your household refrigerator, water cooler, deep freezer, air

conditioneretc. all run on vapour compression cycle. The cycle is called as vapour

compression cycle, because the vapours of refrigerant are compressed in the compressor

of the system to develop the cooling effect.

2.7.2 Working

Here are the various process of vapour compression cycle .

(1) Compression: The vapours of refrigerants enter the compressor and get compressed to

high pressure and high temperature. During this process the entropy of the refrigerant

ideally remains constant and it leaves in superheated state.

(2) Condensation: The superheated refrigerant then enters the condenser where it is

cooled either by air or water due to which its temperature reduces, but pressure remains

constant and it gets converted into liquid state.

(3) Expansion: The liquid refrigerant then enters the expansion valve or throttling valve

or capillary tube when sudden expansion of the refrigerant occurs, due to which its

temperature and pressure falls down. The refrigerant leaves expansion valve or capillary

tube in partially liquid state and partially in gaseous state.

(4) Evaporation or cooling: The partially liquid and partially gaseous refrigerant at very

low temperature enters the evaporator where the substance to be cooled is kept. It is here

where the refrigeration effect is produced. The refrigerants absorbs the heat from tge

substance to be cooled and gets converted into vapour state. Fig 2.7 : Simple VCR

System T-S diagram of VCR SystemFig 2.8 : P-V diagram of VCR System.


LPG REFRIGERATOR

2.7.3 Advantages

Capable of large refrigerating loads at lower initial purchase and operating cost.

Very efficient

Very compact system for small to very large heat loads.

Cycle can be reversed for heat pump operation.

2.7.4 Disadvantages

Parts can wear out.

Noise.

Potential refrigerant leaks.

Operates in limited orientation.

2.7.5 Application

Household refrigerator,

Air-conditioners,

Water coolers,

Ice and Ice cream maker,

Deep freezers,

Large industrial refrigeration and

Air-conditioning systems,

2.8 VAPOUR ABSORPTION CYCLE


LPG REFRIGERATOR

2.8.1 Introduction

The various processes of the vapour absorption cycle are similar to the one in vapour

compression cycle, only the method of compression of the refrigerant is different. In vapour

absorption system ammonia is used as the refrigerant, which has very high affinity to dissolve in

water. Here are various processes of vapour absorption cycle;

2.8.2 Working

(1) Compression or absorption of the refrigerant: in vapour absorption system there is no

traditional compressor, instead there is absorber. The absorber consists of water, as a

absorbent, in which the refrigerant, ammonia, dissolves. This mixture of water and

ammonia is then pumped and heated thus increase in temperature and pressure of the

ammonia occurs. Ammonia leaves the absorber at high pressure and high temperature.

Some work has to be provided to the pump and heating is carried out by the steam. The

amount of electricity required by the pump is much lesser than that required by the

compressor hence there is lots of saving of electricity, however, the additional source of

heat in the form of steam has to be provided.

(2) Condensation: The refrigerant at pressure and temperature then enters condenser

where it is cooled by water and its temperature and pressure reduces.

(3) Expansion: Thereafter the expansion of refrigerant occurs in throttling valve or

capillary tube due to which the temperature and pressure of the ammonia refrigerant

reduces drastically and suddenly.

(4) Evaporation: Finally the refrigerant enters the evaporator where it produces the

cooling effect. It leaves the evaporator in vapour state and then enters absorber, where it

is absorbed by absorbent, water and compressed by the pump. This process repeats again

and cycle continues. There are different types absorbents like water and lithium bromide

that can be used with refrigerant ammonia. These systems are called water absorption

system.

2.8.3 Advantages

No moving parts.


LPG REFRIGERATOR

No vibration or noise on small system.

Small systems can operate without electricity using only heat, large systems

require power for chemical pumps.

Can make use of waste heat.

2.8.4 Disadvantages

Potential refrigerant leaks.

Operates under limited vibration and orientations.

Complicated and difficult to service and repair.

Stalls in a hot ambient

Very bulky.

Poor efficiency.


LPG REFRIGERATOR

CHAPTER 3

LPG REFRIGERATION

3.1 IntroductionAlthough government agencies are not able to continuously supply a major

portion of electricity in both the urban as well as in rural areas. Still the people in these

regions require refrigeration for a variety of socially relevant purposes such as cold

storage or storing medical supplies and domestic kitchens this project has the novelty of

using LPG instead of electricity for refrigeration. This solution is convenient for

refrigeration in regions having scares in electricity. It works on the principle that during

the conversion of LPG into gaseous form, expansion ofLPG takes place. Due to this

expansion there is a pressure drop and increase in volume of LPG that results in the drop

of temperature and a refrigerating effect is produced. This refrigerating effect can be used

for cooling purposes. So this work provides refrigeration for socially relevant needs as

well as replaces global warming creator refrigerants. While going through the literature

review in LPG refrigeration system, Conventional VCR (Vapour Compression

Refrigeration System) uses LPG as refrigerant and produced the refrigerating effect. But

in our proposed very simple type of refrigeration system in which the high pressure LPG

is passing through a capillary tube and expands. After expansion the phase of LPG is

changed and converted from liquid to gas and then it passes through the evaporator where

it absorbs the heat and produces the refrigerating effect. After evaporator it passes

through the gas burner where it burns.

LPG consists mainly of propane (R-290) and butane (R-600), and LPG is

available as a side product in local refineries. In Cuba for already several decades LPG is

used as a drop-in refrigerant. LPG mixtures have composition of a commercial LPG

mixture suitable as „drop-in‟ replacement for R-12 was calculated crudely as 64%

propane and 36% butane by mass. Liquefied petroleum gas (LPG) of 60% propane and

40% commercial butane has been tested as a drop-in suitable for R 134a in a single

evaporator domestic refrigerator with a total volume of 10 ft3. In March 1989, the

Institute of Hygiene in Dortmund Germany needed a new cold storage room. The young


LPG REFRIGERATOR

idealistic director, Dr Harry Rosin, could not consider using a CFC refrigerant and so

tried propane and iso butane. Greenpeace Australia imported a Foron refrigerator in

February 1993 and in December 1993 Email Ltd, Australia’s largest appliance

manufacturer,displayed prototype LPG refrigerators.

3.2 PROPERTIES OF LPG

Colourless

Odourless-(It’s normal to odorize LPG by adding an odorant prior to supply to the

user, to aid the detection of any leaks).

Flammable.

Heavier than air

Approximately half the weight of water.

Nontoxic but can cause asphyxiation.

A good mixture: LPG is mainly Propane (C3H8),Butane (C 4H10) or a mixture of

Propane/Butane.

Since LPG has a simple chemical structure, it is among the cleanest of any

alternative fuel.

Boiling Point: LPG’s boiling point ranges from -42 0C to 0 0C depending on its

mixture percentage of Butane and Propane.

Combustion: The combustion of LPG produces (CO2) and water vapour but

sufficient air must be available. Inadequate appliances fluing or ventilation can result in

the production of carbon monoxide which can be toxic.

Vapour Pressure: LPG is stored as liquid under pressure. It iscolourless and its

weight is approximately half that of an equivalent volume of water. The pressure inside a

closed container in which LPG is stored is equal to the vapour pressure of the liquid and

corresponds to its temperature.

Ignition Temperature: The temperature required to ignite LPG in air is around

5000C.

Calorific Value: The calorific value of LPG is about 2.5 times higher than that of

main gas so more heat is produced from the same volume of gas.


LPG REFRIGERATOR

Toxicity:LPG is colourless, odourless and non -toxic gas. It is supplied

commercially with an added odorant to assist detection by smell.

LPG is excellent solvent of petroleum and rubber product and isgenerally non –

corrosive to steel and copper alloys.

3.3 APPLICATIONS Application of LPG as refrigerant that divides in two categories:

Processes that uses LPG

Industries that uses LPG

Processes that use LPG LPG’s high calorific value makes it a key gas for:

Heating appliances: - used because of its case of combustion, portability and clean

burning characteristics and compatibility with almost all water and space heating

appliances. The best product depends the climate.

Propane: - suitable for use in all conditions. It is the only LPG product suitable for

cold climates (such as the UK and Canada) because of its low boiling point of -43.6 ºF (-

42 ºC).

Butane: - suitable for use in hot climate only because of its higher boiling point of

22.9 ºF (-5 ºC).

Propane/Butane mixtures: - suitable for use in moderate climates.

Cooking: - preferred to electricity by professional chefs.

Oxy-Fuel application: - LPG performs well in large-scale oxy-fuel burner

application. LPG’s clean burning characteristics make it a good gas for:

Transport fuel: - for forklift and other trucks that operate inside warehouses and

factories because it provides no noxious exhaust gases and give more power than

batteries. LPG is also increasingly used as a clean automotive fuel in countries with

serious air pollution problems.

Propane and butane’s low boiling points also give them good closed cycle

refrigerants characteristics (similar to Freon’s).

Industries that use LPG LPG’s calorific and clean-burning characteristics are used

across many industries such as:


LPG REFRIGERATOR

Automotive: - as a forklift truck fuel and in some countries as a private car or

public transport fuel.

Hospitality and Leisure: - as a heating and cooking gas in restaurant, cafes and

mobile catering vans.

Agriculture: - for crop drying, heating g reenhouses and animal sheds and for

flame weeding and pest control.

Construction :- LPG’s portability allow its use for general space heating to enable

work on projects during winter months, and for road heating in bitumen replacement

work.

Chemicals and petrochemicals: - LPG surplus is used as feedstock when prices

are low.

3.4 The LPG Refrigeration Cycle

LPG Gas Cylinder:From the LPG gas cylinder of 14.5 kg, LPG flows through the pipe and reaches to

the capillary tube.LPG gas pressure is approximate 12.41 bars

Capillary Tube:

As the capillary tube, capillary tube downs thepressure up to less than 1.2 bars.

Evaporator:In the evaporator LPG is converted into the vapor from with low pressure. After

passing through theevaporator low pressure and temperature LPG vapor absorbs heat

from the chamber system.

Gas Burner:

After performing the cooling effect, low pressure LPG gas goes into the burner

where the burns. As weknow whenever the fluid flow through the narrow pipe there is a

pressure drop. The amount of pressuredrop in our system is calculated. [10] From the


LPG REFRIGERATOR

Darcey-Weisbach equation, thepressure drop in the refrigerant piping is calculated for 13

feet length tube is 0.23 in terms of equivalent length.

3.5 PARTS OF REFRIGERATORS

3.5.1 LPG Gas Cylinder

LPG is Liquefied Petroleum Gas. This is general description of Propane (C3H8)

and Butane (C4H10), either stored separately or together as a mix. This is because these

gases can be application of a liquefied at a normal temperature by moderate pressure

increases or at normal pressure by application of LPG using refrigeration. LPG is used as

a fuel for domestic, drying can industrial, LPG be horticultural, to agricultural, another

cooking, heating fuel or as LPG processes. Also can be used as automotive specialist

propellant foraerosal

.

Fig 3.5.1 LPG Gas Cylinder


LPG REFRIGERATOR

3.5.2 Capillary Tube

The capillary tube is the commonly used throttling device in the domestic

refrigeration. The capillary of very would occupy used for the the tube is a copper tube of

very less space. The small internal of diameter. It is long length and it is coiled to

refrigeration several turns so that it the capillary tube to 2.28 mm When picture. internal

diameter tube applications varies from 0.5 is shown in (0.020 to 0.09 inch). The capillary

refrigerant enters in the capillary tube, its pressure drops down suddenly due to very

small diameter. The decrease in pressure of the refrigerant through the capillary depends

on the diameter of capillary and the length of capillary. Smaller is the diameter and more

is the length of capillary more is the drop in pressure of the refrigerant as it passes

through it.

Fig 3.5.2 Capillary Tube

3.5.3 Evaporator

The evaporators are another important parts of the refrigeration systems. It

through the evaporators that the cooling effect is produced in the refrigeration system. It

is in the evaporators when the actual cooling effect takes place in the refrigeration

systems. For many people the evaporator is the main part of the refrigeration system,

consider other part as less useful. The evaporators are heat exchanger surface that transfer

the heat from the substance to be cooled to the refrigerant, evaporators’ refrigeration thus

removing the heat from the are used for wide variety in and hence the available from of

the substance. The diverse application in wide variety of shape, sizes and they are also


LPG REFRIGERATOR

classified in different manner depending on the method of feeding the refrigerant,

construction of the evaporator, direction of air circulation around the evaporator,

application and also the

Fig 3.5.3 Evaporator

refrigerant control. In the domestic refrigerators the evaporators are commonly known as

freezers since the ice is made in these compartments. In the evaporators the refrigerant

enters at very low pressure and temperature after passing through the capillary tube. This

refrigerant absorbs the heat from the substance that is to be cooled so the refrigerant gets

heated while the substance gets cooled. Even after cooling the substance the temperature

of the refrigerant leaving the evaporator is less than the substance. In the large

refrigeration plants the evaporator is used for chilling water. In such cases shell and tube

type of heat exchanger are used as the evaporators. In such plants the evaporators are

classified as:

(1). Dry expansion type of evaporators

(2). Flooded type of the evaporators

The evaporators are classified based on the construction as:

(1). Bare tube evaporators


LPG REFRIGERATOR

(2). Plate surface evaporators

(3). Finned evaporators

(4). Shell and tube evaporator

(5). Shell and coiled evaporator, and

(6). Tube-in-tube evaporator

The evaporators are classified based on mode of heat transfer

(1). Natural convection evaporator, and

(2). Forced convection evaporator

The evaporators are classified based on operating conditions

(1). Frosting evaporator,

(2). Non-frosting evaporator,

(3). Defrosting evaporator

3.5.4 Pressure gauges

Many techniques have been developed for the measurement of pressure and

vacuums. Instruments used to measure pressure are called pressure gauges or vacuum

gauges. A manometer could also referring to a pressure measuring instrument, usually

limited to measuring pressures near to atmospheric. The term manometer column

hydrostatic instruments. is often used to refer specifically to liquid Stainless steel

pressure gauge Catering to the requirements of to power and allied array of stainless

Industry, we offer quality steel, weatherproof pressure gauges. Renowned for offering

control equipment, chemicals and petrochemicals and resistance in corrosive

environments and modes, these find wide application in power generation, pollution also

exploration.


LPG REFRIGERATOR

These gauges are available in 63mm, 100mm, and 150mm sizes and can be

customized as per client. Bourdon gauge A Bourdon gauge uses a coiled tube, which, as

it expands due to pressure increases cases a rotation of an arm connected to the tube.

Fig 3.5.4 Pressure Gauges

3.5.5 High Pressure pipes

The range of high pressure pipes covers most steel ball fitted these to both

application where there is a nipples press thus sealing requirement to transfer gas at high

pressure. They consist of a steel pipe with an ends. Two swiveling connection balls

against the seating of the connectinghole and against gas leakage.» » Wide range of

pipes. All pipes are pressure tested to 100 M Pa (14,500 psi) over recommended working

pressure.


LPG REFRIGERATOR

3.6 Basic Experimental Setup of LPG refrigeration systemThe basic components in this system are shown in set up diagram and the changes

in thermodynamicsproperties of the fluid flowing (LPG) is shown in the systems line

diagram.

Fig 3.6 Experimental Setup of Basic LPG Refrigeration System


LPG REFRIGERATOR

3.7 Design of LPG Refrigeration SystemThere are main four parts in this system

1. Copper Tubes (For carrying LPG cylinder to filter before capillary)

2. Capillary tube

3. Valves (Gas supply control valves)

4. Evaporator

3.7.1 Copper Tubes

Air-Conditioning and Refrigeration Systems—Copper is the preferred material

for use with most refrigerants. Because of its good heat transfer capacity as well as

corrosion resistance and cheaperin cost. As for all materials, the allowable internal

pressure for any copper tube in service is based onthe formula used in the American

Society of Mechanical Engineers Code for Pressure Piping (ASME B31)

P = 2S (tmin – C)/ Dmax – 0.8 (tmin – C)

Where:

P = allowable pressure, bar

S = maximum allowable stress in tension, bar

tmin = wall thickness (min.), in mm

Dmax = outside diameter (max.), in mm

C = a constant for copper tube, because of copper’s superior corrosion resistance, the B31

code permitsthe factor C to be zero. Thus the formula becomes:

P = 2Stmin /Dma – 0.8tmin

According to the pressure 100 psi the tube outside diameter is become = 7 mm and the

thickness of thetube is = 1.5 mm.

3.7.2 Capillary tubeAn analytical computation of length of capillary tube The fundamental equations

applicable to the controlvolume bounded by points 1and 2 in fig. are


LPG REFRIGERATOR

1. Conservation of mass

2. Conservation of energy

3. Conservation of momentum

The equation relating state and conditions at points 1and 2 in a very short length of

capillary tube in thefigure is written using following notions [4].

A: Cross sectional area of inside of tube, m²

D: ID of tube, m.

f: friction factor, dimensionless

h: enthalpy, kJ/kg.

hf : enthalpy of saturated liquid , kJ/kg

hg : enthalpy of saturated vapour, kJ/kg

ΔL: length of increment, m.

P: pressure, Pa

Re: Reynolds No., VD/Ʋ

v: specific volume of m³/kg

vf : specific volume of saturated liquid, m³/kg

vg: specific volume of saturated vapour, m³/kg

V: velocity of refrigerant, m/s

w: mass flow rate, kg/s

x: dryness friction

μ: Viscosity, pa×s

μf: viscosity of liquid, pa×S

μ g: viscosity of Vapour, pa×s

For calculation of length of capillary tube we haveused the following relations and find

out the length.

The equation of conservation of mass is as follows

w =V1A/ v1 = V2A/ v2... (1)

or


LPG REFRIGERATOR

w=V1/ v1 = V2/ v2 ... (2)

The conservation of energy gives

1000 h1+ V²1/ 2 =1000 h2+V²2/ 2... (3)

This assumes negligible heat transfer in and out of system. The momentum equation in

words states thatthe difference in forces applied to the elementbecause of drag and

pressure difference on opposite ends of the element equals that is needed to accelerate the

fluid [6].

[(p1-p2) - fΔ L/D V2/ 2v] A = w (V1-V2)..... (4)

As the refrigerant flows through the tube, its pressure and saturation temperature

progressively drop and thefraction of vapour .x. continuously increases. At any point

h = hf (1-x) + x hg.... (5)

v = vf (1-x) + x vg..... (6)

The quantities of equation (4) V, v and f all change as refrigerant flows from point 1 to 2.

Simplifying usingequation (2)

f ΔL/D. V2/ 2v = f ΔL/D V/ 2 w/A...... (7)

In the calculation to follow, V used in equation (7)will be mean velocity

Vm = V1+ V2 / 2..... (8)

The friction factor with turbulence is

F= 0.33/Re 0.25 = 0.33/ (VD/ μ v) 0.25... (9)

The viscosity in two phase flow is given by

μ = μf (1-x) + x μg.... (10)

The mean friction factor fm applicable to incrementallength 1-2 is

fm = f1+f2/2 = [0.33/Re1

0.25 + 0.33/Re2

0.25]/ 2... (11)

The essence of the analytical calculation is to determine the length ΔL between points 1-2

as shownin fig. for a given reduction in saturation temperature of the refrigerant. The

flow rate and other conditionsat point 1 are known and for a required selected

temperature at point 2, The Remaining conditions atpoint 2 and ΔL would be computed

in the following steps:

1. Temperature t2 selected


LPG REFRIGERATOR

2. p2, hf2, hg2, vf2, and vg2 are computed, all beingfunction of temperature (or

pressure).

3. Combination of equation (2) and (3) gives

1000 h 2+ v²2/ 2 (w/A)2 =1000 h1+ v²/ 2... (12)

Substituting equations (5) and (6) into (12)

1000 hf2 +1000(hg2- hf2) x + [{vf2+ (vg2 - vf2) x}

²(w/A) ²] = 1000 h1 + V1

2/ 2...... (13)

In equation, all quantities being knows except x,which could be solved by quadratic

equation,

X= [-b+√b2-4ac]/2a.... (14)

Where,

a = (vg2- vf2)2 (w/A) 2×1/2

b= 1000(hg2- hf2) + vf2 (vg2 - vf2) (w/A) and

c = 1000(hf2- h1) + (w/A) 2 1/2 vf2 2- V1 2/2

Properties of LPG at 10.27 bars [16]

hf1 = enthalpy of saturated liquid = 169.1kJ/kg

hg1 = enthalpy of saturated vapour = 498.0kJ/kg

vf1 = specific volume of saturated liquid = 2.050×10-3m³/kg

vg1= specific volume of saturated vapour =

0.0448m³/kg

Properties of LPG at 1.67 bars

hf2 = enthalpy of saturated liquid = 22.9kJ/kg

hg2 = enthalpy of saturated vapour = 435.0kJ/kg

vf2 = specific volume of saturated liquid = 1.763×10-3m³/kg

vg= specific volume of saturated vapour =

0.2585m³/kg

w = V/v

V= volume flow rate = 1.1liter/ hr

w =9.45×10-4 Kg/sec

From this calculation the length of capillary tube is= 2.97m


LPG REFRIGERATOR

3.7.3 ValvesIn this system we have used two flow control valves of globe type of 4 mm of

internal diameter.

3.7.4 EvaporatorEvaporators are heat exchangers with fairly uniform wall temperature employed

in a wide range ofHVAC-R products, spanning from household to industrial applications.

In general, they are designedaiming at accomplishing a heat transfer duty at the penalty

of pumping power. There are two well establishedmethods available for the thermal heat

exchanger design, the log-mean temperature difference (LMTD) and the

effectiveness/number of transfer units (e-Ntu) approach (Kakaç and Liu, 2002; Shah and

Sekulic, 2003). The second has been preferred to the former as the effectiveness, defined

as the ratio between the actual heat transfer rate andthe maximum amount that can be

transferred, provides a 1st-law criterion to rank the heat exchanger performance, whereas

the number of transfer units compares the thermal size of the heat exchanger with its

capacity of heating or cooling material. Furthermore, the e-Ntu approach avoids the

cumbersome iterative solution required by the LMTDfor outlet temperature calculations.

[14] In general, evaporators for refrigeration applicationsare designed considering the

coil flooded with twophase refrigerant, and also a wall temperature close tothe refrigerant

temperature (Barbosa and Hermes, 2012), so that the temperatureprofilesalong thestreams

are not constant, in these cases, the heat transfer rate if it is calculated from: [13]

Q = m.cp (To – Ti) = ɛ.m.cp (Ts − Ti)

Where m is the mass flow rate, Ti, To and Ts are the inlet, outlet and surface

temperatures, respectively,

Q=h × As (Ts-Tm) is the heat transfer rate,

Tm is themean flow temperature over the heat transfer area,As, and ɛ is the heat

exchanger effectiveness,calculated from (Kays and London, 1984):

e = 1 – exp (−NTU)


LPG REFRIGERATOR

Where NTU is the number of transfer units. We have selected the plate and tube type

evaporator because itprovides a gentle type of evaporation with low residence time. It

also preserves the food and otherproducts from bacterial attack. It requires low

installation cost.


LPG REFRIGERATOR

3.8 Design calculations for evaporatorThe evaporator has following dimensions:

Length = 325 mm, Breadth = 265 mm and

Height = 135 mm

The evaporator is made from six plywood sheets of 3mm thickness which enclose six

thermocol sheets of10mm thickness.

The areas for these sheets are as follows:

Area1 = 265×135 = 0.03578 m2,

Area2 = 265×325 = 0.08612m2,

Area3 = 265×135 = 0.03578m2,

Area4 = 265×325 = 0.08612m2,

Area5 = 325×135 = 0.04388 m2,

Area6 = 325×135 = 0.04388 m2,

Thermal conductivity of plywood kp = 0.12 W/m.k

Thermal conductivity of thermo coal kt = 0.02 W/m.k

Thickness of plywood = 3 mm

Thickness of thermo coal = 10 mm

Temperature of atmosphere = 35 0C = 298 K

Temperature of evaporator = 16 0C = 289 K

Heat flow from area 1 due to conduction

Q1 = (Ta-Te)/ (Rthp + Rtht)

= (Ta-Te)/ ((Lp/KP.A) + (Lt/Kt.A))

= (294-289)/ (0.698+13.97)

= 2.317W

Heat flow from area 2 due to conduction

Q2 = 5.58 W, Q3 = 2.32 W, Q4 = 5.58 W, Q5 = 2.84 W

Q6 = 2.84 W

Total heat flow from all areas due to conduction =

21.47 W


LPG REFRIGERATOR

Heat flow from evaporator due to convection

Inside heat transfer coefficient = 30 W/m2.K

Outside heat transfer coefficient = 10 W/m2.K

Rate of heat transfer Q [12]

Q =U.A. (Ta-Te)

The overall heat transfer coefficient

1/U = (1/Uo) + (Lp/kp) + (Lt/kt) + (1/Ui)

1/U = 0.649

U = 1.54 W/m2.K

Rate of heat transfer from area 1

Q1 = 1.54×0.03578(298-264)= 1.873W

Q2 = 4.50 W, Q3 = 1.873 W, Q4 = 4.50 W, Q5 = 2.29W

Q6 = 2.29 W

Total heat flow from all areas due to convection =17.326 W

Heat transfer due to radiation Q

Q = σT4

= 5.67× 10-8(35-(16)) 4

= 0.21W

Total heat flow from evaporator due to conduction, convection and radiation

Qt = 21.47+17.326+0.21

=39.006W


LPG REFRIGERATOR

The experiment of this project was done on 8 May, 2015 at 11:00 a.m. and readings were

taken at 10 minute's interval, for 1 hour which is as shown in table 1 below:

Table 3.8.1: Experimental Readings

Sr

No

Inlet

Pressure

(Bar)

Outlet

Pressure

(Bar)

Time

(min)

Capillary

Temp 0C

Evaporator

Temp 0C

Water

Temp 0C

1 5.745 3.009 10 32 32 32

2 5.745 2.941 20 28 30 31

3 5.745 2.804 30 26 26 29

4 5.745 2.530 40 25 21 29

5 5.745 2.530 50 24 18 27

6 5.745 2.462 60 22 16 26

Again we were taken reading on this project on same day on at 3:30 p.m. and readings

were taken at 10 minute's interval, with same cylinder for 1 hour which is as shown in

table 2 below:

Table 3.8.2: Experimental Readings

Sr

No

Inlet

Pressure

(Bar)

Outlet

Pressure

(Bar)

Time

(min)

Capillary

Temp 0C

Evaporator

Temp 0C

Water

Temp 0C

1 5.608 2.941 10 30 31 32

2 5.608 2.872 20 28 29 31

3 5.608 2.736 30 27 26 29

4 5.608 2.599 40 25 23 28

5 5.608 2.462 50 24 19 27

6 5.608 2.394 60 22 17 27


LPG REFRIGERATOR

10 20 30 40 50 600

5

10

15

20

25

30

35

Water Temperature

Water Temperature

Chart.1:Water Temperature v/s Time (min)

10 20 30 40 50 600

5

10

15

20

25

30

35

Evaporator temperature

Evaporator temperature

Chart.2:Evaporator Temperaturevs Time(min)


LPG REFRIGERATOR

Fig. p-h diagram of LPG Refrigerator

Size of refrigerator: - 335×265×135 mm³

Initial temperature of water: - 30⁰C

Initial temperature of evaporator: - 33⁰C

Specific heat of LPG vapor is 1.495kJ/KgK


LPG REFRIGERATOR

Refrigerating effect

The properties of LPG at 5.516 bars are

Enthalpy h1 = 430.3 kJ/Kg

Temp. t1= 4 ⁰C

The properties of LPG at 1.316 bars are

Enthalpy h3 = 107.3 kJ/Kg

Temp. t3= -30 ⁰C

Heat extracted from evaporator in 1 hour (Qeva) = Heat gained by LPG (QLPG)

(Qeva) = Heat extracted from (water + surrounding air inside of evaporator +container +

leakage)

mw = mass of water =6.5kg

cpw = specific heat of water=4180J/kg.K

(ΔT)W =28.3 0C

mc =mass of container =1.30kg

cpc= specific heat of aluminium container = 903J/kg.K

(ΔT)c =28.3 0C

xLPG = Dryness fraction of LPG from graph =0.5

(Qeva) = Qevap + Qair +Qcont +QL

= mwcpw(ΔT) + macpa(ΔT) + mccpc(ΔT) +QL

We have taken 6.5 kg of water in an aluminiumcontainer of weight 1.30 kg.

Since there is very less amount of air so it is neglected.

= 6.5×4180×28.7 + 0 + 1.3007×903×28.7

= 0.81348 MJ

Heat gained by LPG (QLPG) = Latent heat gain(QL)LPG +Sensible heat gain(QSen)LPG

= mLPG .xLPG .hfg + mLPG .cpLPG. (Tsup-Tsat)

=9.45×10-4×0.5×375×103×3600+9.45×10-4×1.67× (- 9.3-30)

= 861151.662J/hr = 0.862MJ/hr

So the refrigerating effect is = h3-h2

= 630.3-307.3

= 323kJ/Kg


LPG REFRIGERATOR

For work input we have a LPG cylinder of 14.5 Kg. so the work input is amount

of energy required for filling of 1 cylinder. A typical LPG bottling plant has the following

major energy consuming [8].

Equipment:-

1. LPG pumps

2. LPG compressors

3. Conveyors

4. Blowers

5. Cold repair facilities including painting

6. Air compressors and air drying units.

7. Transformer, MCC & DG sets

8. Firefighting facilities

9. Loading and unloading facilities

Some of the LPG bottling plants use a comprehensive monitoring technique for

Keeping track of energy / fuel Consumption on per ton basis. PCRA Energy Audit [8]

1. Consumption = 40×4200=168000kWh

2. For lighting energy consumption= 227340kWh

3. LPG compressor consumption= 153360 kWh

1. Total consumption for LPG pumps

One pump having 40 kW motor and 96 m head or 150cubic meter /hour discharge

Annual operating = 4200 hrs

Annual energy 6 hrs /day in 350 days

= 168000+227340+153360

= 548700kWh

Per day consumption

= 548700/350

=1567.71 kWh

500 cylinders are refilled every day, so per cylinder electricity consumption.

=1567.71/500

=3.1354kWh


LPG REFRIGERATOR

For filling of 1 LPG cylinder of 14.5 kg the power input is

= 3.1354kWh

So 1 kg of LPG is

= 3.1354/14.5

=0.2162 kWh

We run the set up for 1 hr

= 0.2162×1000/ (9.45/10000) ×3600

= 63.55W

COP OF THE LPG REFRIGERATION SYSTEM

COP = (h3-h2)/w

= (630.3-307.3)/63.55

= 5.08

After finding out the COP of the LPG refrigerator we found out the heat librated by LPG

after burning in the burner with the burner efficiency of 92 %.

Heat liberated by LPG QL= m×cv

We have the volume flow rate of LPG is 0.1 liter per minand the specific volume of LPG

at 1.56 bar pressure is 1.763×10-3 m3/Kg.

So mass flow rate of LPG is = 0.0001/1.763×10-3= 0.0567 Kg/min

m = 9.45×10-4 Kg/sec

cv = 46.1 MJ/Kg

QL= 9.45×10-4× 46.1×103

= 43.56 W


LPG REFRIGERATOR

3.9 Cost Estimation of LPG RefrigerationCOST SHEET NO COMPONENT COMPONENT PRICE

1 EVAPORATER BOX 500

2 GAS PIPE 175

3 CAPILLARY TUBE 150

4 ACCUMULATOR 450

5 COPPER TUBE 300

6 INSULATOR THERMOCOL 50

7 BRAZING MATERIAL 200

8 SUCTION PIPE 175

9 C U ‘T’ CONNECTOR 350

10 BRASS NUT 175

11 HAND SUT VALVE 175

12 PRESSURE GAUGE 500

13 STRAIGHT CONNECTOR 175

14 SCREW, NUT,BOLT 300

15 BRAZING GAS CYLINDER 150

16 HIGH PRESSURE VALVE 200

17 BURNER 450

18 GAS COST 900

TOTAL COST: Rs 5375/-


LPG REFRIGERATOR

3.10 Advantages It eliminates the blocking problem.

It is efficient to save fuel.

Low Weight.

The fridge works when electricity off. It is efficient to save fuel.

No Pollution.

Running cost is zero.

Eliminates the compressor and condenser.

Noiseless

3.11 Disadvantages LPG is explosive in nature.

Do not maintain constant pressure in LPG cylinder.

Put the LPG cylinder is inverted position.

After the refrigeration processes, the exhaust of LPG is burn into burner. Because

of the exhausted vapour LPG can not converted again liquid phase , because the

this process is very costly. The prevention of leakage of the LPG is the major

problem in LPG refrigeration system. Because of the LPG is highly flammable.

3.11 APPILICATIONS


LPG REFRIGERATOR

Food processing, preservation and distribution

1. Storage

2. Fish

3. Meat and Poultry

4. Dairy Products

(a). Ice cream

(b). Butter

(c). Cheese

(d). Butter milk

5. Beverage

6. Candy

7. Medical

Conclusion


LPG REFRIGERATOR

The aim of the LPG refrigerator was to useLPG as a refrigerant and utilising the

energy of the high pressure in the cylinder for producing the refrigerating effect. We have

the LPG at a pressure of 12.41 bar in Domestic 14.5 kg cylinder equipped with a high

pressure regulator and this pressure has reduced up to 1.41 bar with the help of capillary

tube. But if we use a low pressure regulator as is the practice in conventional domestic

LPG gas stove, the pressure of LPG after the expansion device and before the burner

would be different. So we have calculated the refrigerating effect with the help of

changes in properties of LPG (pressure, temperature, and enthalpy) before and after the

evaporator using high pressure regulator and the amount ofrefrigerating effect is

323kJ/Kg.

Future Scope


LPG REFRIGERATOR

Positive result of experimentation pushes me to go ahead with this normal product

and introduce new product range in the field of refrigeration. Which focus on the

restaurant and Community hall, and mid-day meal of school and college to decrease the

product and cost and for preserving vegetables ,milk etc.at small lair and snacks shop by

increase the portability of the refrigerator by reducing the weight and eliminating the

compressor with no cost of refrigerating and light weight and light maintenance free

product.

It may very useful for the desert, research and mines area and many other area of

under developed country, where electricity not easily available.

It can be apply for the system as an air conditioning in LPG cars.

This system most suitable for hotel, industries, refinery, chemical industries

where consumption of LPG is very high.

References1. Shank K. Wang, Handbook of air conditioning and refrigeration” Edition.


LPG REFRIGERATOR

2. A. Baskaran, P. Koshy Mathews, International Journal of Scientific and Research

Publications”, Volume 2, Issue 9, 1 ISSN 2250- 3153, September 2012

3. B. O. Bolaji, Investigating the performance of some environment-friendly refrigerants

a alternative to R12 in vapour compression refrigeration system”, PhD Thesis in the

Department of Mechanical Engineering, Federal University of Technology Akure,

Nigeria (2008).

4. Prashant Sharma, Rahul Sharma, “International Journal of Latest Research in and

Technology” ISSN (Online):2278- 5299 Vol.1,Issue 1 :45-48,May-June(2012)

5. ASHRAE, “Thermo physical Properties of Refrigerants”, Chapter 20, ASHRAE

Fundamental, Inc. Atlanta 20 (2001) 1-67.

6. W. F Stoecker., and J. W. Jones, “Refrigeration and Air conditioning”, TATA

McGraw-Hill pub.

Co. Ltd.pp. 264.

7. ASHRAE, 2002, “Adiabatic capillary tube selection”, Refrigeration Handbook,

chapter. 45, pp.45.26-45.30, ASHRAE.

8. “PCRA energy audit report”, HPCL LPG bottling plant AsaudaBahadurgarh (Haryana)

Dec. 2006.

9. “Basic statics on Indian petroleum and natural gas” 2006-07.

10. Shank K. Wang, “Handbook of air conditioning and refrigeration” page no. 11.14

chapter 11.

11. ASHRAE handbook 1998.

12. C.P. ARORA, “Hand book of Refrigeration and air conditioning”, by page no. 425

13. A. Bejan, “The thermodynamic design of heat and mass transfer processes and

devices”, Heat and Fluid Flow pp.258-276, 1987

14. Hermes CJL, “Conflation of e-Ntu and EGM design methods for heat exchangers

withuniform wall Temperature”, Int. J. Heat andMass Transfer, pp.3812-3817, 2012.

15. J R Barbosa, C Melo, CJL Hermes, PJ Waltrich, “A Study of the Air-Side Heat

Transfer and Pressure Drop Characteristics of Tube-Fin ‘No-Frost’ Evaporators”,

Applied Energy 86, pp.1484-1491, 2009.


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