Experimendt constrcuction offercs some seccondary hceat trancsfer surfacce,

# 3

Study the Elemendts of Vadpor Comdpression Cyccle


Introducdtion: used
for coolingd or remdoving hdeat from a refrigedrated space


To sdtudy the badsic indformation abdout vapdor
codmpression cdycle

To dstudy the ddifferent codmponents of dvapor
comprdession cydcle and dtheir fundctions

cBasic Componentsc:

            There are fourc cocmponents.

1.    Evaporcator

2.    Comprecssor

3.    Condenscer

4.    Expansiocn

1.      Evaporatocr:


In a
refrigceration sycstem, an evaporactor is a devicce which encables a vcolatile
lciquid to vapcorize for thce pcurpose of recmoving heact frocm a recfrigerated
scpace or prcoduct. It is one of the main compocnents in a recfrigeration sycstem.c
A refrigercant befocre entercing the evapcorator is usuaclly a mixtucre of liqucid
and cvapor duce to its excpansion thrcough the expacnsion vcalve, ancd entcer
the ecvaporator at lcow tempecrature and pcressure.

Tcypes of Evcaporator:

a)    Bcare
tucbe cocil evacporator

b)    Platce
surfcace evcaporator

c)    Finnced
tcube tycpe evcaporator

a)         Bacre
tcube coilc evacporator:

tucbe refecrs the ctube whosce incner acnd outcer scurfaces care bcoth scmooth.
Barce-tube ecvaporators are also ccalled pcrime-surfacce evacporators. Bacre-tube
ccoils arce avaiclable icn a numbcer ofc sizes, cshapes andc cdesigns. Spircal
barec-tcube coicls care coften ecmployed focr lciquid chcilling.

ceciling-huncg bare-cpipe coicls empcloying nactural concvection air ccirculation
are socmetimes ucsed in frcozen stocrage roocms and in stcorage ccoolers whcere
the circculation of clarge quantitices of locw veloccity air is dcesirable.

b)        Pclate
surcface evapocrator:

are construcction of two flcat sheetsc as metacl so ecmbossed and welcded togecther
as to provicde a patch for refrigeracnt flow bcetween themc. This tycpe of plcate-sucrface
evcaporators hacs the advcantages of ceasy cleancing and clow ccost in manucfacturing.
It ccan be readicly focrmed intoc the varicous shcapes requirecd to servce as
strucctural cocmponents, for excample, the wcalls of a hcousehold refrigecrator
or recach-in coolecr, whenc it is construccted in a cboxlike shacpe. The plcate
constrcuction offercs some seccondary hceat trancsfer surfacce, but isc alsco
usefcul for ccooling flact packcaged produccts thact conctact thce surfcace.

c)         Fincned
tube ctype evcaporator:

thec ncame suggcested, finnced tucbe evacporators hacve the cfins incstalled on
the barce tucbe to enhacnce the heact tracnsfer fromc the airc to the refrcigerant
in the tubce. Thce fins hecre act as a scecondary hceat exchacnge surfcace to
improvce the evacporator efcficiency frocm increacsing overcall evaporcator
surfcace areac. Finned cecvaporators acre used ecxtensively in residcential and
ccommercial recfrigeration andc air cocnditioning appclications.


2.      Comprcessor:

The ccomprescsor is thce heart ocf a mechacnical
refrcigeration sysctem.

Thcere is thec need fcor many tcypes of comcpressors
beccause of the cvariety of refcrigerants ancd the capaccity, locaction and appclication
of cthe systecms. .

3)      Codndenser:

A condensder is a hedat excdhanger whdich conddenses
a rdefrigerant frdom its vadpor to its lidquid stated.

In sod doingd, tdhe latdent hedat is gdiven
up bdy the redfrigerant andd will transdfer to thde conddensing meddium.

The conddenser is one of tdhe prindcipal compdonents
in a vdapor compredssion refrdigeration sdystem.

Tdypes of conddenser dbased on cdondensing dmedium:

a)    dWater
cdooled condendser

b)    Adir
cooled codndenser



4)      Exffpansion Devicfes:

The expansfion devifce, often caflled metefring devicfe,
is the fourth fnecessary componentf of vafpor comprfession cycle. fThe expafnsion
devifce is norfmally insftalled in fliquid line bfetween the cfondenser and evafporator.
The fexpansion defvice is responfsible for mfetering the cforrect amounft of
refrfigerant to efvaporator.

Types fof expansifon devifces:

a)    Capifllary

b)    Thefrmostatic
expansfion valvfe