ICE PLANT
1
ACKNOWLEDGEMENT We, the stud studen ents ts of D.M.E. belonging to the “ICE PLANT” batch, expressing thanks to our beloved guide M. SANDEEP B.E., fro his active participation and excellence guidance at every stage and high dynamic dynamic and motivativ motivative e encourage encouragement ment in successfu successfully lly completing of this project. We
highly
thankful
to
our
Sri. Sri.
B.
for for his his coop cooper erat atio ion n
in
beloved
PARDHASARADHI, ARDHASARADHI, M.E., M.I.S.T.E..,
Princ Principa ipall
completing our project. We are also thankful to our beloved Head o !"e Mec"anical
En#ineerin# Depar!$en! Sri. T.%ENKATESWARA RAO, B.E., for his cooperation and encouragement encouragement in completing this project. We are are also also than thankf kful ul to the the sta sta and and ab ab !echn echnic icia ians ns of "echanical #ngineering $epartment for their cooperation. %lso %l so,, &e high highly ly than thankf kful ul to all all othe otherr &ho &ho are are dir directl ectly y and and indirectly indirectly involved, involved, &ith full co'operatio co'operation n to complete complete our project project &ork.
Pro&ec! A''ocia!e'(
(
CONTENTS
PAGE NO. )* INTROD+CTION((((((( INTROD+CTION(((((((((((((((((((( (((((((((((((((( ((( (
)
* METHODS
O-
RE-RIGERATION((((((((((((((((( /* ICE
MAKING
S0STEM((((((((((((((((((((((..
)1
2* BASI BASIC C E3+IPMENTS((((((((((((((((((((((( ) 4* CLASSI-ICATIONS E%APORATORS(((((((((((((
O1
5* MAKING
O-
ICE((((((((((((((((((((((((.. 7* MAN+-ACT+RING ICE(((((((((((((((((((
6 O-
/5
* ICE CALC+LATIONS(((((((((((((((((..
MAKING /
)
6* TECHN TECHNO O -EASIB -EASIBILI ILIT0 T0 REPOR REPORT T
ON ).4 ).4 TON ICE ICE PLANT PLANT
(((.
*
INTROD+CTION "oder "odern n refrige refrigerat ration ion has many many applicat application ions. s.
!he +rs and
probabl probably y still the most important important is the preserv preservation ation of food. food. "ost foods foods kept at room temperatu temperature re spoil rapidly rapidly.. !his is due to rapid rapid gro&th of bacteria. %t usual refrigeration, temperatures of about *.* *- /, bacteria gro& gro& 0uite slo&ly. slo&ly. ood ood at this temperature temperature &ill be preserved preserved for longer time. efrigeration efrigeration preserves preserves food food by keeping keeping it cold. 2ther important use of refrigeration includes %ri 3onditioning, beve bevera rage ge cool coolin ing g and and humi humidi dity ty cont contrrol. ol.
"any "any manu manufa fact ctur urin ing g
processes also use refrigeration.
HISTOR0 4
!he refrigeration industry became important commercially during the 15th century. #arly refrigeration &as obtained by the use of 63#. !he use of natural ice re0uired the building of insulated containers or ice boxes for stores, restaurants and homes.
!he units +rst
appeared on a larger scale during the 7ineteenth 3entury.
6ce &as +rst made arti+cially about 15(- as an experiment. 7ot until 15)* did arti+cial 6ce manufacturing became practical. ittle arti+cial 6ce &as produced until shortly after 158- during 158-, a &arm &eather resulted in a shortage of 7atural 6ce. !his helped to start the mechanical 6ce making industry.
6n 15)* 9%32: ;#<67= and %merican #ngineer invented the apparatus &hich &as the fore runner of our modern compression systems. 6n 1544, a >erman #ngineer produced the +rst %bsorption type of refrigeration mechanism, although "ichael araday had discovered the principles for it in 15(*.
?????
@
BASIC TERMS +SED IN RE-RIGERATION RE-RIGERATION8 efrigeration is the science of providing and maintaining temperature belo& that of surrounding ambient/ temperature”.
!he
terms
"%67!%67
implies
the
continuous
extraction or removal of heat from a body &hich is already at lo&er temperature than its surroundings.
HEAT8 Aeat is a form of energy. !his is evident from the fact that heat can be converted in to other forms of energy and that other forms of energy can be converted in to heat. Aeat as a molecular energy is almost
universally considered thermodynamics.
!he
metric unit of heat is joules 9/. =ince all other forms of energy may be converted in to heat, it is considered to be an energy in its lo&est from the availability of heat energy to do &ork depends on temperature are dierential, available heat energy is al&ays kinetic in nature.
LATENT HEAT 8 atent heat dierence from sensible heat in that it does not cause a temperature rise &ith in a body, but does eect a change in its of being atent heat is generally speaking the amount of heat re0uired to change the state of a substance.
SENSIBLE HEAT 8 Aeat &hich results in an increase in temperature of a matter &ith out changing its state is kno&n as sensible heat. When the temperature of &ater is raised from (-B to @-B 3 the heat observed to eect this change is sensible heat. 3hange in sensible heat of a substance is given by the follo&ing e0uation &hen there is change in temperature, C D Wt !E F !G/ &here !E H !G
SPECI-IC HEAT CAPACIT08 I
!he speci+c heat capacity of a substance is the amount of heat that must be added or released to change the temperature of 1k.g of substance to 1B k.
TEMPERAT+RE AND TEMPERAT+RE MEAS+REMENT 8 !emperature is a property of matter and it is the measure of intensity of heat or heat level and it has a relative value. 6t indicates the degree of &armth or ho& hot or cold the substance or body is.
ike other forms of energy heat can be measured because it has 0uantity and intensity. Aeat is not visible, but manifests itself in its eects on various substances. %ddition of heat increases the volume or substance or pressure at constant volume.
!his property is used for measuring the
temperature &ith the help of mercury thermometer and gas thermometer. %s the temperature of substance increase the color also changes, this property@ is used for measuring the temperature in radiation pyrometers.
RE-RIGERATING E--ECT O- ICE 8 6ce is still important to the refrigeration industry. 6ce change to &ater at -B 3 and %tmospheric pressure.
Aeat absorption to
produce this change is ))@ kjJk.g. !he =peci+c Aeat capacity of 6ce D (.1kjJ kg !he atent Aeat of usion melting/ of 6ce D ))@ kjJkg
5
!he speci+c Aeat of &ater F *.18kjJjk B <
ICE AND SALT MI9T+RE8 6ce changes to &ater at -B c )( / !herefore to get the lo&er temperature re0uired in some instance, ice salt mixtures are used. !hese mixtures, 6ce and salt 6ce and 3%31, lo&er the melting temperature if 6ce. %n ice and salt mixture may be made &hich &ill melt at 15B 3 B /.
!he reason that the ice and salt mixtures
produce lo&er temperatures is that the salt causes the ice to melt faster.
METHODS O- RE-RIGERATION AND APPLICATION !he =cience of refrigeration utiliKes several methods providing temperature dierential facilitating heat transfer bet&een the bodies. ollo&ing are the various methods of refrigeration. • • • • • • • • • •
6ce efrigeration $ry 6ce efrigeration %ir #xpansion efrigeration #vaporative efrigeration >as throttling efrigeration =team 9et efrigeration i0uid >as efrigeration Lapour 3ompression efrigeration Lapour %bsorption efrigeration !hermo #lectric efrigeration
8
APPLICATION O- RE-RIGERATION APPLICATIONS8 ollo&ing
are
the
fe&
applications
of
the
science
of
efrigeration. •
• • • • • • • • •
3omfort
air
conditioning of residential buildings, hotels,
auditoriums, hospitals, oMces, tool rooms etc. "anufacturing and preserving of medicines. "anufacturing of 6ce. ;reservation of :lood and human tissues. ;rocessing of ;hotographic materials. 3ooling of concrete for dams. !reatment air for blast furnaces. ;rocessing of 3hemical products. ;roduction of rocket fuels. 3omputer functioning.
1-
ICE MAKING S0STEM !he manufacture of arti+cial ice &ill al&ays occupy a large sector of the refrigeration industries presently making ice by several dierent processes, dependent on &hether distilled &ater or ra& &ater is desired.
;roduction of arti+cial ice takes t&o dierent
forms, depending on re0uirements, as N
). Can Ice . Pla!e Ice Can Ice8 6n the 3an system, the &ater is placed in galvaniKed iron can or moulds immersed in a brine tank &hich is kept cool by ammonia expansion coils.
6n this system unless means are
introduced to prevent it, air and other impurities have a tendency to collect in a core in the centre of the can.
"aking 6ce from distilled
&ater &ill eliminate this trouble, but due to its higher cost, it is not &idely used. %t the present time, the tendency is to ra& &ater and to agitate it in order to eliminate the air and impurities this agitation is usually accomplished by special agitation e0uipment by a refrigerant air jet or by special air piping.
Pla!e Ice 8 6n the plate system &hich is still used but is not being installed in ne& plants to any large extent/, hollo& pans through &hich cold brine or/ %mmonia circulates are immersed in a tank of &ater until ice of 5 to 1( inches thick is formed.
!he plate is
arranged so as to allo& the li0uid ammonia to feed into it and the gas to return to the compressor in the usual manner.
11
PLATE ICE MADE B0 ONE O- THE -OLLOWING METHODS
)* DIRECT E9PANSION S0STEM 8 6t consists of direct expansion, Kig'Kag coils &ith ) mm plates of iron bolted are riveted in place. !he tha&ing of the face of the ice is accomplished by turning the hot 7AO gas from the machine direct into the coils.
* DIRECT E9PANSION S0STEM 8 6t is similar as explained above except the coil is immersed in a brine solution contained in a &ater and brine tight cell. !ha&ing is accomplished by turning hot gas in to the coil.
/* BRINE COIL PLATE S0STEM 8 6t is similar to direct expansion plate except the brine is circulated through ammonia.
the coil instead
of
!ha&ing is accomplished by means of &arm brine
circulated through the coils.
1(
BASIC E3+IPMENT efrigerating e0uipment mainly consists of compressor, condenser, evaporator, and expansion device.
#ach component is said to be
interdependent on the other.
COMPRESSOR 8
3ompressor is heart of the vapour compression
system. 6t is device by an electric motor and is located bet&een the evaporator and condenser.
3ompressor compresses the vapour
refrigerant dra&n from the evaporator and discharges to the condenser.
CLASSI-ICATION 8 3ompressors are classi+ed into several types based on dierent criteria as follo&s N
Cri!eria 1. "ethod of compression
T:pe o Co$pre''or eciprocating, otary,
(. %ssembly of "otor
3entrifugal, scre&. 2pen or 6nterdependent
). *. 4. @. I.
=emihermatic, Aermatic Lertical, AoriKontal. =ingle cylinder, "ulti cylinder =ingle %cting, $ouble %cting $irect $riven, :elt $riven L.W. adial on 6n'ine.
%xis 7umber of cylinders Working of Puid $rive "ethod of construction
1)
SINGLE ACTING RECIPROCTING COMPRESSOR 8 !he capacity of the compressor depends on the number and siKe of the cylinders, its speed, the eMciency of compression, the suction and discharge pressures and the number of hours of operation per day. =ingle acting reciprocating compressors are generally used &ith • •
efrigerants &hich have lo& speci+c volume efrigerants re0uiring small displacement of piston and high condenser pressure
!hese compressors are suited for ;lants of Q tones to 1--- tons capacity. =uch compressors are available in siKe ranging from -.1
OPEN T0PE COMPRESSOR 8 2pen type reciprocating compressor is one &hich is directly coupled to an electric motor or driven by belt drive.
!he motor compressor as a single unit is mounted on the
same base plate. %nother feature of this unit is that the condenser as &ell as the receiver tank are also mounted on the same plate as sho&n in the +gure. %dvantage of this unit is its easy maintenance and refrigerant can be charged &ith the help of same compressor and motor.
HERMETIC AND SEMITHRMETIC COMPRESSORS 8
Aermetic
compressor is one that is enclosed in a &elded shell along &ith its motor and totally sealed from the atmosphere. !he advantage of this type of compressor is N 3omplete prevention of refrigerant leakage, compact and occupies a small place, less noisy, eective cooling of motor &inding.
!hese are
&idely used in small plants such as $omestic refrigerators, freeKers and &indo& air conditioners. 1*
Aermetic or =emi hermetic compressors are built in siKes from 4
ROTAR0 COMPRESSORS 8 otary compressor employs a rotating member in place of reciprocating piston. !hey area available in either open or hermetic types otary compressors are classi+ed as follo&s N • • • •
oller type otary 3ompressors. Lane type otary 3ompressors. =cre& 3ompressors. 3entrifugal 3ompressors.
irst three types are of positive displacement type and the centrifugal compressors are of non positive displacement type.
ROLLER T0PE ROTAR0 COMPRESSOR 8 !his type of compressors of 4 to @ tones capacity are used in domestic refrigeration and freeKers. !hey are used up to @
%ANE
T0PE
ROTATOR0
COMPRESSOR8
these
types
of
compressors are suitable for lo& temperature applications such as domestic refrigerators, freeKers and small air conditioning packages. !hey handle refrigerants &ith lo& speci+c volume at lo& suction pressures. :oth roller and vane type compressors &hen operating at lo& speeds 14-- to )--- ;"/, have a lo& compression ability than reciprocating compressors.
14
SCREW
COMPRESSOR
8
=cre& compressors combine
the
advantage of centrifugal and reciprocating compressors and are increasingly used in large systems such as food storage. !hey may eventually replace reciprocating designs.
!hey
can handle large
volume of refrigerant. With a compression ratio as high as (1, they have high compression eMciency. !hey pose no surging problems. !hey are being &idely used in air conditioning units up to around 4tons capacity.
NETRI-+GAL COMPRESSOR 8 3entrifugal compressors are used in large installations ranging from (-- to 1-,---
CONDENSERS 8 latent
heat
from
3ondenser is a component &hich abstracts the the
high
pressure
temperature and same pressure.
refrigerant
at
constant
6t removes heat absorbed by
refrigerant in the evaporator and the heat of compression is added in the compressor and condense it back to li0uid. or this purpose, the condenser employs a cooling medium such as air or &ater.
CLASSI-ICATION O- CONDENSERS 8
3ondensers are broadly
divided into three types. !hey are a/ %ir 3ooled 3ondensers. b/ Water 3ooled 3ondensers. c/ #vaporative 3ondensers.
AIR COOLED CONDENSER 8 !he circulation of air over an air cooled condenser may be either by natural convection or by the action of fan or blo&er.
1@
%ir cooled compressors employing fans or blo&ers provide forced air circulation. 6t may be divided into t&o types according to the location of the condenser as • •
3hassis mounted emote mounted
%ir cooled condensers are available in siKe ranging from less than 1
WATER COOLED CONDENSERS 8
Water cooled condensers are
again classi+ed into three types. !hey are i. ii. iii.
=hell and coil condenser $ouble tube condenser. =hell and tube condenser.
SHELL AND COIL CONDENSER 8 !he shell and coil condenser is made up of one or more bar tube coils enclosed in a &elded steel shell.
!hese condensers are simple in construction.
!hey are
suitable for small and medium capacities around 4- tons.
DO+BLE T+BE CONDENSER8
6t consists of t&o concentric
cylindrical tubes one inside the other.
SHELL AND T+BE CONDENSER 8 6t is the most commonly used condenser. 6t consists of cylindrical steel shell in &hich a number of straight tubes are arranged in parallel. :aRes are provided to prevent sagging of tubes. =hell and &ater tube condenser are available in capacities ranging from I
E%APORATI%E
CONDENSER
8
#vaporative
condensers
are
commonly used in large %mmonia plants such as 6ce making, :ottle coolers etc., as they are found to be cheaper. !he cooling produced 1I
is approximately ((@-
less space, Pexible for
indoor or outdoor location, needs relatively &ater for cooling, &ater cooling is assisted and accelerated by air, they combine they functions of condenser and cooling to&ers.
E9PANSION DE%ICES 8 :asically, they are of t&o types viK., variable restriction type and 3onstant restriction type. %n expansion device is needed in every compression refrigeration system to control the Po& of li0uid refrigerant into the evaporator. Aigh
pressure
li0uid
refrigerant
from
compressor
via
condenser/ Po& into an expansion device &hich expands it do&n to evaporator pressure. #xpansion device also meters the 0uantity of Po& of refrigerant through it into the evaporator. !he example of variable
restriction
type
is
automatic
expansion
valve
and
thermostatic expansion valve. #xample of constant restriction type is 3apillary !ube.
A+TOMATIC E9PANSION %AL%E 8 !his is also called as constant pressure expansion valve since it maintains constant pressure in the evaporator. !he automatic expansion valve is not suitable for a varying load re0uirement. 6t is ho&ever used in applications &here precise control of the evaporator temperature is needed and &here cooling load is more or less constant. 6ts use is limited to plants of capacity less than )-
THERMOSTATIC E9PANSION %AL%E 8
7ame of the valve is
misleading because control is not actuated by the temperature in the operator. :ut by the magnitude of S=uper heatT of the suction vapour leaving the evaporator.
Aence it is more appropriately
called. =uper heat control valve. !his valve is so precise in action
15
that it regulates the rate of Po& of li0uid refrigerant into the evaporator in exact proportions to its rate of evaporation. !hermostatic
expansion
valves
are
&idely
used
in
air
conditioning and many other refrigeration systems.
SOLENOID %AL%E 8 =olenoid valve is often called magnetic valve. 6t is +tted in the line just prior to an expansion valve. ollo&ing are the uses of =olenoid valve. •
6t cuts o the li0uid refrigerant Po& in the li0uid line controlled by a pressure s&itch &hen section pressure raises to a point
•
• •
that &ould over load the motor. 6t shuts o the li0uid Po& in a line controlled by a thermostat &hen the desired lo& temperature is reached. 6t isolates coils in suction line during defrosting operations. 6t acts as a by'pass &all to reduce the capacity of compressor.
18
CAPILLAR0 T+BE 8 !i is +xed restriction type expansion device. 3apillary tubes 1 to @ mts. long &ith an inside diameter generally from -.4 to ( mm. area available for use in small siKe plants. %dvantages in this tube is simple in construction &ith moving parts, inexpensive, lo& starting tor0ue motor is enough to drive the compressor.
E%APORATORS 8 S#vaporatorT is a component &hich absorbs heat from the surroundings to be cooled by using a volatile li0uid called refrigerant. Cuick evaporating refrigerant Po&s through the coils of evaporator and absorbs the heat of products placed in it, evaporates and changes into li0uid state. !he heat picked up by the refrigerant is carried to the compressor and then to the condenser.
(-
CLASSI-ICATION O- E%APORATORS #vaporators are classi+ed as follo&s based on dierent criteria.
Cri!erion
T:pe o e;apora!or looded type, $ry or direct
1. efrigerant feed
expansion type, li0uid over feed type :are tube evaporator, plate
(. =urface construction
surface type, +nned tube evaporator rosting type, $efrosting type,
). 2perating conditions
non'forsting type ;rimary air cooling type 1/ 7atural convection type (/ orced convection type )/ i0uid cooling type
*. 3ooling medium
Walk in coolers, li0uid chillers $ouble pipe chillers :andlot chillers 4. =pecial design !ank type chillers =hell and coil chillers =hell and tube chillers
DR0 E9PANSION E%APORATOR 8
(1
6n this, the dry expansion coil is not dry but as a refrigerant control device that admits only enough li0uid refrigerant to be completely evaporated by the time it reaches the outlet of the coil. efrigerant leaves the evaporator in a fully dry state. !hese type of evaporators re0uired much smaller charge of refrigerant. !hey are &idely used in
plants
of
capacity
belo&
14-
tons
@--
-LOODEED T0PE E%APORATOR8 !he Pooded type evaporators have the advantage that the surface of evaporator coils in contact &ith the refrigerant under all load conditions.
!hey provide high
rate of heat transfer. !hey are bulky in siKe and are used in large installations.
((
BARE T+BE E%APORATIORS 8 !he bare tube evaporator contains simple piping coil to receive the li0uid refrigerant. 6t Po&s through the coil and evaporates as it receives heat from the surroundings. =teel pipes are used fro %mmonia refrigerant and copper tubes for reon refrigerants. !hese are used in &ater chillers &hich employ certain secondary refrigerants.
PLATE E%APORATORS 8 ;late evaporator has its coils &elded onto a plate or placed bet&een t&o plates &hich are &elded together at their edges. !his arrangement increase area of contact of tubes and thus higher rate of heat
transfer from surroundings to the
refrigerant li0uid.
()
DRIER8
$riers are meant to remove moisture content in a
refrigeration station !hese are installed in li0uid line bet&een condenser and expansion valve.
T0PE O- DRIERS 8 $riers are also called “$ehydrators”. !hey are of three types viK. 1/ =ealed type or thro& a&ay type driers. (/ e+ll type $riers. )/ =trainer +lter type $riers.
SEALED T0PE DRIER8 6n this drier, the components are sealed and cannot be repaired.
!he main moisture absorbing
“descant” used in this drier is
silica gel.
agent
i.e.,
!his substance fully
absorbs the moisture and dries up the refrigerant.
!he +lters
provided in the drier remove dust particles and any foreign matter in refrigerant.
(*
RE-ILL
STRAINER<-ILTER DRIER8 !he drying agent used in this type of drier is silica gel. !heses are &idely used in domestic refrigerator, &indo& type air conditioners etc.,
T+BING 8 "ost tubing used in refrigeration and air conditioning is made of copper. Ao&ever, some aluminum steel, stainless steel and plastic tubing is also being used. "ost copper tubing used in air conditioning and refrigeration &ork is kno&n as %ri'3onditioning and efrigeration %3/ tubing. %3 tubing is usually charged &ith gaseous nitrogen to keep it clean and dry until it is used.
7itrogen should be fed through it
during braKing and shouldering operations. !ypes of tubing. =oft copper tubing Aard dra&n copper tubing
-REE=ING TANKS 8 reeKing tanks are made up of such materials as &ood, steel or concrete. Wooden tanks have a relatively short life and are subject to leaks.
or this reason, freeKe thanks made of
steel cost &ith a &ater proof paints are preferable. !anks made of reinforced concrete are also recommended as being superior to those made of &ood. !he freeKing tanks contain direct expansion freeKing coils e0ually distributed throughout the tank and submerged
in brine.
!he tank is provided &ith a suitable hard &ood frame for supporting ice cans and a propeller or agitator for keeping brine in motion. !he brine in tank acts as a medium
of contact only.
!he ammonia
(4
evaporating in the freeKing coils extract the heat from the brine, &hich again absorbs the heat from &ater in cans thereby freeKing it. !he brine temperature should be maintained at 1- to (- B and back pressure in %mmonia coils from (- (5 pounds per s0uare inch, &hich is e0uivalent to a temperature at 4 to 14 B in coils.
RE-RIGERANTS % refrigerant is any substance &hich acts as cooling agent by absorbing heat from another substance.
6t is &orking agent or
media employed in a refrigeration system. efrigerant is the Puid used for heat transfer in a refrigeration system &hich absorbs heat at a lo& temperature and lo& pressure.
PRIMAR0 RE-RIGERANTS 8 1. (. ). *. 4.
I1I %mmonia 7AO/ I** 3arbon $ioxide 3oE/ I@* =ulphur $ioxide =oE/ 11 !richloro Puoro methane 3c1O/ 1( $ichloro $iPuoro methane 3c1EE/ (@
SECONDAR0 RE-RIGERANTS 8 1. I(8'air (. I15'&ater
PROPERTIES O- AN IDEAL RE-RIGERANT8 1. (. ). *. 4. @.
6t should be non poisonous 6t should be non explosive 6t should be non corrosive 6t must be non Pammable eaks should be easy to detect 6t should be non toxic
AIR PIPING 8 %ir piping &hen used must be carefully installed according to the manufacturing speci+cations.
!he air to
blo&er is usually dra&n from under the frame &ork and returned from the blo&er to the laterals &ithout any further conditioning.
!he temperature of air in the lateral must be
kept at *@ to 4- B. 6n order to prevent freeKing of moisture in them or freeKing of ice on the drop pipes, keep air pressure as lo& as possible, usually from 1 Q pounds to 1 U pounds is suMcient. 6n exceptional cases, t&o pounds may be necessary. :e careful &hen putting the +tting into drop to leave it sitting at an angel &hich ensures a free s&inging of tube. !he secret of good ice is in keeping the tube at centre of the can. "ake the core spotlessly clean before re+lling &ith fresh &ater. ;ull the ice regularly, a de+nite number of blocks per hour on the day.
-ILLING 8 !he cans are usually +lled by means of a +ller device &hich is so constructed as to automatically shut o the &ater supply &hen the can is +lled to the propter height. !he +ller is inserted in the can and &ater is turned on. %s the can +lls, a Poating ball raises until the can is +lled to the right dept, &hen the ball automatically closes a valve. !he life of 6ce cans are increased by this method of handling as compared to usual (I
careless and injurious procedure follo&ed &hen +lling a can at a time.
INEERIOR ICE 8
3loudy or milky ice is usually caused by
presence of air. 6t may be due to de+cient reboiling, the over &orking at reboiler or due to insuMcient supply of steam to the distilled &ater condenser, in such case rapid condensation of steam cause a vaccum, &ith the result that air is dra&n in and mixed &ith &ater. !o remove the ice, the can are lifted out of the brine and sprayed &ith or dipped in &arn &ater. 6n many cases it comes from over &orking of boiler, carrying too much &ater.
ICE REMO%AL 8 !o remove the ice, the cans are lifted out of the brine and sprayed &ith or dipped in &arm &ater.
!his
loosens the ice so that &hen the can is inclined on its side. !he cake slides out. !he cans are usually tapered to facilitate easy removal of ice.
ICE STORAGE 8 "anufactured ice is stored very much in the same manner as natural ice, insulation being the most important factor.
=trips of lathe, sa& dust in the south rice
cha, are used for packing it. !he space allo&ed per ton of ice should be about 4- 3u.feet.
"anufactured ice is usually
shipped in cars, &here it is packed and insulated the same as &hen putting in storage. 6ce storage &arehouses are usually e0uipped &ith a cooled anti rooms.
(5
WATER TREATMENT Water treatment to render &ater more suitable for 0uality ice, freeKing must be restored.
Vndesirable &ater 0ualities can result
poor ice formation as to color, residues and tendencies or to =hafter of crack. treatment.
Water should be analyKed to determine the bene+ts of "ajor advances have occurred in the means for &ater
treatment, some so advanced though costly/ as to render agitation unnecessary and by or permitting freeKing at faster rates &ith extremely cold brines. =&eet &ater is preferable of limpid ice. %ll &ater lines must be galvaniKed. done by sand or 0uartK +lters.
Water treatment can be
;eriodic soaking and &ashing of
&ater +lters and treating &ith soda ash is statutory method for cleaning and removing discoloration causes in the ice and serves for unkno&n reasons as inhibitor against their recurrence for a time.
(8
PROCED+RE O- ICE MAKING 3lean &ater is taken is galvaniKed cans &hich are placed in a brine tank. :rine acts as a secondary refrigerant solution of =odium 3hloride, 7acl or 3acl/. 3ooling coils or evaporator coils are &ound around the cans &hich carry the refrigerant in them. !he brine in the tank is chilled about 1-B3 by the refrigerant reon/.
LaporiKed refrigerant Po&s too compressor &here it is
compressed
and
delivered
to
condenser
follo&ing
a
vapor
compression cycle. Lapor refrigerant is condensed to li0uid state in the condenser and the li0uid refrigerant is collected in the receiver tank. !hen it Po&s through a strainer and expansion valve &hich reduces pressure.
its
o& pressure li0uid refrigerant keeps on Po&ing in the
evaporator coils and absorb heat from brine.
!he chilled brine
extract heat of &ater in the containers until the &ater freeKes into ice.
3ans are slightly tapered so that ice blocks can be
removed by simply &rapping or shaking them.
easily
%lternatively, the
cans are lifted our of brine tank after ice formation and placed in hot &ater tank called !A%W67> !%7<.
:y tha&ing operation, ice blocks
can be easily removed. #ntrapped air and 3oE in ice render a milky appearance.
!p
produce
transparent
and
good 0uality
ice,
chemically treated pure and clean &ater is to be used.
)-
PRINCIPLE THERMOD0NAMIC C0CLE O- %APO+R COMPRESSION RE-RIGERATION S0STEM !he standard L3 system comprises the follo&ing operations N
)< COMPRESSION 8
eversible adiabatic compression of vapour
refrigerant from saturated vapour pressure, ; c to
condenser
pressure, ;c !emperature of vapour rise from !1 to !(.
6rreversible rejection of heat at constant
pressure ; ( D ;)D ;3/ !his cause desuperheatinig and condensation of refrigerant. Lapour refrigerant heat loss, e0uivalent to its latent heat, to the cooling medium circulated in the condenser.
Lapour
condenses to li0uid from.
/<2 E9PANSION 8 6rreversible expansion at constant enthalpy from saturated li0uid pressure to the vapour pressure. i0uid refrigerant is throttled do&n isenthalpically from ! ) to !* . #xpansion &all serves this purpose and it also measures the 0uantity of Po&.
2<) E%APORATION8
everesible addition of heat at constant
pressure, li0uid refrigerant absorbs heat e0uivalent to its latent heat from the products places in the evaporator.
i0uid vaporiKes to
vapour state.
)1
%ssume unit mass of refrigerant Po&ing through the system. et 7D efrigeration eect per cycle W DWrok supplied per cycle !hen 7 D #nthalpy 1 #nthapy */ D A1 ' A* D A1 ' A) XXXXXXXXXX A* D A) A1 ' h)
XXXXXXXXXX
A) ' h) li0uid enthalpy
Y W D
-ACTORS A--ECTING %APO+R COMPRESSION S0STEM E>ec!in# o S?per"ea!in# 8 Ao& the superheating results in is discussed in %rt ).* =uperheated cycle is sho&n in ig.
)(
#ects
of
superheating
the
suction
vapour
from
saturation
temperature t 1 to t1 i.e., by adding a superheat of Z t •
=peci+c volume of vapour sucked in increased thus reducing
•
the mass Po& rate and decrease the capacity. 6ncrease in refrigerating eect from A 1 ' A* to A1 ' A* by an
•
amount Z A 6ncrease in &ork supply from A( ' A1 to A( ' A1 3.2.; may increase, decrease or may not alter . #ach degree of superheat &ill cause a greater
•
cycle eMciency. 4 to (-B of superheat is al&ays desirable.
• •
reduction in
E>ec! o ?nder Coolin# or S?@
belo& the condensing temperature for a given
pressure is kno&n as sub'cooling or under cooling. ! :y installing a sub cooler bet&een the condenser and the expansion valve, the li0uid efrigerantcoming of the
condenser may be cooled to a
temperature belo& its saturation temperature. =ub'cooling is sho&n in ig. by the line )T '). #ects of sub'cooling are
))
• • • • • •
6ncrease in the refrigerating eect educes Pashing of li0uid during expansion ;o&er re0uirement per ton of refrigeration &ill reduce 6ncrease of 3.2.; =ub'cooling is generally resorted to 4 to 1-B only. lash gas/ is the vaporiKed refrigerant. When saturated li0uid expands through an expansion valve the fraction of refrigerant it vaporiKed.
E>ec!' o C"an#in# E;apora!or Pre''?re 8
ig. =ho& the eects of changing the evaporator pressure keeping the condenser pressure constant. =upposing evaporator pressure is reduced i.e.,
suction
pressure of compressor is decreased by say -.* bar &e +nd that • • • •
efrigerant eect decrease from A 1 T F A*T/ to A1 ' A*/ =peci+c volume increase thus reducing mass Po& rate $ecrease in volumetric eMciency 6ncrease in compressor &ork from A( T ' A1T/ to A( ' A1/ $ecrease of 3.2.;.
E>ec! o c"an#in# Coden'er Pre''?re 8
)*
ig.
=ho&s the eect
of changing the condenser pressure i.e.,
delivery pressure of compressor keeping constant.
evaporator pressure
6f condenser pressure is increased by say/ 1.( bar, &e
observe that • • • •
6ncrease in po&er consumption i.e. 6ncrease in compressor &ork from A ( T ' A1T/ to A( ' A1/ $ecrease in refrigerating eect from A 1 T ' A*T/ to A1 ' A*/ $ecrease of 3.2.;./
MAN+-ACT+RING O- ICE !he time to freeKe a give thickness of ice is determined +rstly by the temperature of the ice freeKing surface, in the case the top brain.
"ost ra& &aters, treated or untreated, cannot be froKen
&ithout cracking at a temperature belo& 1(T3.
!he brain velocity
also has a marked inPuence on the freeKing time and should not exceed above 1-4 rpm. !he brain movement is caused by hydraulic gradient best designed for about ).( to ).5 cm in the tank length.
)4
!he brain level in the tank should permit the submergence of &ater in the ice cans belo& the brine level. % uniform rate of harvesting exactly according to the time schedule is necessary for maximum yield. !he rate of ice freeKing drops rapidly.
%s the ice layer becomes thickness, the thermal
resistance to heat transfer increases. % (5 cm ? 4@ cm can holding 1*4 kg of &ater in 1*Tc, brine &ill make 1(I kg of ice in (* hours and consumers and additional 1* hours to freeKe the remaining 15 kg. When brine agitation is moderate, *.4 to I.4 mpm, the total freeKing time for V= standard cans, (5 cm thick may be expressed by the e0uation 1 [ ( -.@b( ! D
' 1/ 't/
Where t D !emperature of brine, S3 : D !hickness of 6ce :lock short side/ 3m. !
!otal freeKing time for the blocks hours
! D
nm ? (* '(/ 1---
Where n D 7umber of cans per metric ton of ice produced in (* hours " D "ass of 6ce block, kg. #0uation ) is obtained by e0uation '1' and '(' and solving for the brine temperature ! D
(4b\ J nm ')/
!hus, for a given ;lant, the daily output is a function of the brine temperature only. !he number of cans per ton is the usual unit for rating tank capacity, &hich also establishes the necessary brine temperature for a given daily output. )@
or :lock thickness above )- 3m. or belo& (4 3m. #0 )/ should not be used, because of the follo&ing reasons. 1/. 6t assumes that all resistance to heat Po& is dependent upon ice thickness, &here as the resistance actually consists of a/ b/
6ce resistance thickness/ and =urface resistance from brine to 6ce/
Which is independent of the 6ce !hickness.
(/. 6t does not take into consideration, the Po& of heat across narro& sides of the can, &hich becomes increasingly important as the shape of can approaches a s0uare. !he value of the Aeat transfer coeMcient various &ith the brine velocity. or every high brine velocities (54 W m]\ F k]^ for 2rdinary ice tanks &ith relatively slo& moving brine, D 1*- W m]1 ' k]^ .
)I
ICE MAKING CALC+LATIONS
CAPACIT0 8 6ce making capacity is usually e0ual to about 4-_ to I-_ of the refrigeration capacity
as expressed in terms of
refrigeration per day. Ao&ever, such operating conditions as initial temperature of &ater supply, room temperature and eectiveness of insulation &ill inPuence this ratio.
6f heat leakage losses are
kno&n, the 6ce making capacity can be closely estimated.
HEAT LOSSES 8
Aeat losses in 6ce making usually very from less
than 1-_ in the best installations upto a possible 4-_ under poor conditions. When the 6ce production and refrigeration rating of the machine is kno&n, the heat losses may be calculated.
-REE=ING TIME 8 !ime re0uired for freeKing 6ce depends upon the temperature of brain and thickness of cake &ith a brine at about 14B, 6t &ill take approximately 4- hours to freeKe 11 U inches of ice. !he time for freeKing may be calculated mathematically, if it is remembered that, fro dierent thicknesses. %n emphirical formula has been used to determine forgoing time for ice in cans as follo&s. reeKing time in hours %t\ J )('! Where
t D &idth of ice at top narro& &ay/ !D !emperature of brine in T % D % constant usually takes as I
TON O- RE-RIGERATION E--ECT 8 !he cooling capacity of older refrigeration units is often indicated in “tons of refrigeration”. % ton of refrigeration represents the rate of cooling produced &hen a ton (-- 1b/ of ice melts during one (* hour day. 1 ton D %pprox. 8-I kg.
)5
atent heat D ))I <9Jkg. #nergy absorbed D atent heat ? &eightD))I ? 8-I <9Jkg ? kg/ D )-4.@48 <9 !he melting of this 6ce in one day has a cooling capacity/
TRO+BLE SHOOTING SOME O- THE COMMON PROBLEMS 8 1. (. ). *. 4. @.
!he system runs but for a short time. !he system is very noise. #vaporator temperature is very high 3ools occasionally on s&itching of the system. i0uid lines freeKes i0uid line extremely hot
SOME O- THE COMMON CA+SES O- TRO+BLES 8 1. aculty location of the unit (. %ir in the refrigeration system ). o& suction pressure *. Aigh suction pressure 4. Aigh head pressure @. oad on evaporator not proper I. 3logged condenser 5. efrigerant shortage, efrigerant over charge 8. Libration or noise in the system 1-. o& ambient temperature 11. efrigerant control device leaking 1(. $efective condenser fan or driving system. 1). estricted li0uid line. 1*. Lery lo& voltage, starting capacitor fault
running
capacitor fault or burnt out. 14. 6mproper &iring, loose connections.
SOME O- THE REMEDIAL ACTIONS -RO A%ODING PROBLEMS 8
)8
1. or &ater pumps, remove foreign matter, check and correct direction of rotation and +r tight for the base. (. ubrication is necessary for eective running of pump motor and compressor. ). =trip and clean all strainer, valves, check pressure drip through the system. *. emove obstructions. 4. 3heck and if possible remove cause of excess of load for all the units namely condensing unit. @. 6nvestigate load at evaporator, if necessary, +t not gas by pass system. I. 3heck the eMciency of components, if necessary replace. 5. 3heck refrigerant charge and li0uid line strainer and drier check &hether head pressure control is necessary. 8. eplace compressor if noise is interval 1-. 3heck supply at motor and correct the voltage 11. 3heck all the &earing parts and replace.
*-
SPECI-ICATIONS AND DETAILS OBASIC E3+IPMENT
). COMPRESSOR
a/ 3apacity
D
U A;
b/ ;ressure
D
)- cans
c/ 3ompany
D
$eltron'6ndia D . MOTOR
d/ =peed
14-- rpm a/ 3apacity
D
U A;
b/ 3ompany c/ =peed
/. CONDENSER
D
D
Lijay
1**- rpm
a/ 3apacity
D
U A;
b/ $imensions Aeight
D 1(”
:ase
D &idth
1*” D
( U”
2. RECEI%ER
4. PIPE 8
a/ Width
D )”
b/ ength
D1(”
a/ #vaporator coil
D )J5”
b/ 3ondenser to receiver to evaporator D 1J*
5. %AL%E 7. RE-RIGERANT 8
%t evaporator entry
D 1J*
reon F 1( ;ressure F 1( bar
. CHAMBER SPECI-ICATIONS 8
ength ? Width ? $epth 1*” ?
1-” ? 1(”
6. ICE CANS
ength
?
Width
?
$epth
D
ength
?
Width
?
$epth
D
5”?(1J(”?@”
PLANT SI=E 4”?1*”?14”
*1
INTROD+CTION
!his report gives a detailed idea about a small scale industry. “XXXX #ducated young people should not depend on salary jobs and should try for self employment. 6t is only possible &hen young engineers and technical persons are &illing to take risks for our country to prosper”. :efore going to put a small scale industry, investment in &hich does not exceed rupees )4 lakhs in plants and machinery irrespective of the number of persons employed.
SCOPE 8 %t present, small scale industries account for about *-_ of the total combined industrial production. account for 1-_ of the +xed capital
=mall scale units
of all factories, provide
employment to *- lakh persons. !his is )4_ of the total number of employees in the industries and this section contributes nearly )4_ of total industrial output and (@_ of total exported. =mall industries have large scope in our country.
!oday, 3entral and =tate
>overnments are providing all types of help to the interested person.
ROLE O- SMALL SCALE IND+STR0 8
*(
1. !hese create immediate and permanent employed on a large scale. (. !hey help in production of consumerTs goods and therefore can meet the demand for consumer product. ). !hey help reduction of prices. *. !hey accelerate the rate of industrial gro&th.
PROCED+RE TO START A SMALL SCALE IND+STR0 8 =tarting a small scale industry is not an easy task. %t the same time, it is not diMcult too, if dierent factors are considered before taking decision to start it. !he factors involved are 1. "arket survey and study of the product as regards their demand in the market.
(. ). *. 4.
$ecide the prospectus and the
necessary factors to manufacture on the basis of a/ "arket =urvey b/ inancial implications involved c/ !echnical kno&'ho& available d/ #xperience in the line etc., [ =election of proper site for locating the unit. ;reparation of schemes. %pproval of schemes. egistration of small scale industry.
*)
SELECTION O- PROD+CT
=election of product is the key point to start an industry before selecting a produce. 1. 3onduct market survey and study the product. (. %s regards their demand in the market. ). =tudy similar products available in the market that can be probable competitors analiKe them as regard their utility, their dependability and the main of all, 0uality and cost. *. $ecide the product you are going to manufacture on the basis • • • •
of "arket survey inancial implications !echnical kno&'ho& available #xperience in the line etc.,
6n this project, “=election of product” is based on the 6ce "aking =ystem.
**
MARKET S+R%E0 % =urvey is conducted by an entrepreneur to ensure himself future sales of his proposed product. % survey can be conducted as often as possible to predict changes in the demand. "arket survey is done by collecting data from representative section of society in selected areas or to&ns.
"arket survey
involves more expenditure and time but is more eective and gives clear picture. "arket survey gives details about competitors manufacturers of the same product/, traders and consumers. "arket
survey
gives
the
information
about
competitors
regarding installed and utiliKed capacities of the product, terms of business, marketing areas, trade practices, plans fro expansion and silent features like 0uality +nance and other resources. "arket survey gives the information about the distributors and retailers regarding the business terms, turnover, his relation &ith suppliers of other products, normal levels of stocks and their valuable comments. "arket
survey
gives
the
information
about
consumers
regarding annual consumption, their present source of supply, his preference to other brands, purchasing po&er, purchasing criteria and his reactions to the change in the product 0uality and design.
*4
PROD+CT AND PROD+CT ANAL0SIS
;rocess products such as sugar and cement are manufactured by continuous production. "ass production is manufactured in large number of products like !ransistor. When a +rm manufactures several products, each product in manufactured for some length of time. =uch type of production is called batch production.
When the +rm manufactured only a fe&
products in an year such as =tem !urbine or :oilers, it is called 9ob ;roduction. !hus, if same product is manufactured in job production, cost is more.
:ut cost is cheap &hen it is manufactured in mass
production. =o price of a product depends on volume of production. Cuantitative analysis of product should be done consulting the product life cycle graph given.
*@
MATERIALS AND INP+TS =uppliers are major manufactures of materials
as identi+ed.
3omparative statements regarding terms and conditions, time re0uired to materialiKe order, minimum order 0uantities and packing methods.
!he entrepreneur
must obtain test certi+cates from
suppliers or he should get the material tested for 0uality if necessary, &hen some materials are critical. !he availability of ra& materials must be studied closely &ith information of previous years &hether actual or arti+cial shortages of materials occurred for previous years. ;recautions must be taken to control such shortages.
6mported ra& materials and materials
controlled by the >overnment need more attentions as supplies &ill not be regular.
INP+TS 8 "en, machines, materials, money and management are +ve inputs or/ 4"Ts of an industry. "achines should be carefully selected.
#ntrepreneur should
ask suppliers, the list of industries to &hom he &as centered. Ae should select, if available, the machines approved by $.>.=. [ $. $irector >eneral or =upplies and $isposals/ &ho issues certi+cate or approval after through testing. "anagement is another criteria.
6f the 6ndustry is large,
technical managers must be appointed &ho &ill reduce the cost of production. #ntrepreneur can read the text books ono management and can a 0uaint himself managerial kno&ledge.
"oney generated by pro+ts should not be diverted to unnecessary non productive uses. =uMcient reserve fund must be developed to cater the needs of unforeseen events. >reat economy must be observed as money may be blocked and generally
*I
entrepreneur faces monitory troubles fre0uently in the early years of his 6ndustry.
MAN POWER 8 selected.
e0uired number of skilled persons may be
=emi skilled and unskilled persons must be trained in
similar industries.
!hey must be made production conscious and
0uality conscious to achieve maximum results. =cienti+c &age rate systems maybe adopted, productivity linked &ages and bonus may be given to the sta.
6f may be remembered that 9apan could
compete &ith all other 3ountries, because, if a man is employed, he is employed for life.
LOCATION 8 ;lant location may be de+ned as “the functioning determining &here the plants are to be located for maximum operating economy and eectiveness.
*5
ECONOMIC AND TECHNICAL E%AL+ATION ECONOMIC E%AL+ATION 8 #conomic evaluation is presentation of information regarding the pro+tability of proposed industry convince +nancial institutions for sanction of loans
and also enable the
entrepreneur to convince himself about the success of his project. 6t should be examined &hether the >overnment has priority for the proposed product. 3osts of inputs, cost of production, cost of oMce and sale revenue.
;ro+t should be suMcient to ensure return on
investment to entrepreneur.
$ebt service coverage ratio must be
e0ual to or more than t&o. 2ther&ise, +nancial institutions agitate to sanction such projects.
TECHNICAL E%AL+ATION 8 important
factor
=election of
&hich
forms
!echnical basis
for
#volution is economic
another
valuation.
manufacturing process, machineryTs capacities are
critical. 6f a product can be manufactured by alternative process, the cost of production by dierent processes should be analyKed to arrive at economic system of process. $ierent processed need dierent machinery &hich again have dierent capacities.
3apacities of machines have to be select
according to rate of production and siKe of the product, automations may be introduced &here ever necessary. 6f ra& materials have dierent alternativeTs the merits
and
demerits should be analyKed and suitable materials are selected.
*8
STAT+TOR0 RE3+IREMENTS WITH GO%ERNMENT DEPARTMENT IN SETTING +P SMALL IND+STRIES REGISTRATION LICENSE 8
=mall scale industries have to be
registered &ith >eneral "anger, $istrict 6ndustries 3entre of 3ommissioner of 6ndustries. registered
&ith
arge and "edium =cale are to be
3ommissioner
of
6ndustries
or
=ecretary
to
>overnment, %; 6ndustries and 3ommerce $epartment. ;artnership +rms are to be registered &ith egistrar of irms, %; =tate >overnment. ;rivate or ;ublic imited 3ompanies are to be registered &ith egistrar of 3ompanies are to be registered &ith egistrar of 3ompanies of 3ompany a& :oard of >overnment of 6ndia. and and 6ndustrial #states &ill be provided by %; 6ndustrial 6nfrastructure 3orporation.
%ny >overnment and ;rivate and if
large area is re0uired/ can be re0uired &ith the help of $istrict 3ollector or =ecretary of >overnment, 6ndustries $epartment.
LICENSES 8 ;anchayat icenses for construction of :uildings and 6nstallation of "issionary should be obtained by >ram ;anchayat. "unicipal icense is re0uired for establishing an 6ndustry and for storage of some critical items, from "unicipality, actory plans for&arded by the >ram ;anchayat should be approved by 3hief 6nspector of actories. egistration of a factory and license are to be obtained by local inspector of factories, in most cases, #lectricity supply &ill be given only after approval or 4-
6nspector of factories, on application to ocal $ivisional #ngineer of %.;. =.#.:. egistration of =cale !ax egistration should be done &ith 3ommercial !ax 2Mcer.
SPECIAL LICENSE 8 !hese are re0uired for some critical items and conditions such as instillation of boilers, manufacture of explosive, %lcohol and its
products, drugs and 3osmetic, Aandloom and
!extiles, ood grains, oods ;roducts,
PREPARATION O- -EASIBILIT0 REPORT 8 ;reparation of project report of feasibility report is done 1/ !o set guidelines for future action (/ !o procure +nance from :ankers )/ !o obtain egistration, to procure a& materials from >overnment %gencies and to obtain icense to import machinery and a& materials from concerned %uthorities. ;roject eport should include a/ >eneral information regarding industry b/ ;reliminary analysis of alternatives c/ "arketing plan d/ 3apital re0uirements and costs e/ inancial and #conomic %nalysis.
41
PROECT REPORT SHO+LD INCL+DE THE -OLLOWING 8 1. (. ). *.
ocation and its advantages. =ite and its advantages. "arket %nalysis. $ierent alternatives for production and their merit and
4. @. I. 5.
demerits. =peci+cations of ;roduct. %dvantage due to >overnment ;olicies. =peci+cations of a& material. %nalysis of =ources and =uppliers of "issionary and a&
"aterials. 8. %dvantage of !echnology of collaborating 3=6 aboratories of forms. 1-. 3ost and data details of land and :uildings. 11. lo& charts, ;rocess 3harts [ :uilding ayout. 1(. e0uirements of employees. 1). Working capital re0uirements. 1*. %nalysis of pro+tability. 14. und lo& =tatement. 1@. #nvironmental problems and their preventionTs 1I. ;ast performance of promoters of the project. 15. ;reparedness to implement the ;roj. e. &ithout delay. 18. %vailability of ;o&er and Water.
4(
