TITLE.PM5

160 ENGINEERING THERMODYNAMICS

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/M-therm/Th4-4.pm5

Condensate out

Steam in

Water in

Water out

ejtw 2

ejtw 1

Fig. 4.38. Condenser.
Assuming there are no other heat interactions except the heat transfer between steam and
water, then
Q = Heat gained by water passing through the condenser
= mw (hw 2 – hw 1 ) = mw cw (tw 2 – tw 1 )
Substituting this value of Q in eqn. [4.60 (a)], we get
h 1 – h 2 = mw (hw 2 – hw 1 ) = mw cw (tw 2 – tw 1 ) ...[4.60 (b)]
where, mw = Mass of cooling water passing through the condenser, and
cw = Specific heat of water.

4.12.8. Evaporator

An evaporator is an equipment used in refrigeration plant to carry heat from the refrigera-

tor to maintain the low temperature. Here the refrigerant liquid is passed through the evaporator

and it comes out as vapour absorbing its latent heat from the surroundings of the evaporator.

Fig. 4.39 shows the system. For this system

Refrigerant

liquid in

Refrigerant

vapour out

Evaporator

Q

Fig. 4.39. Evaporator.