Page 161 - DJJ20063- Thermodynamics 1

DJJ20063- Thermodynamics 1

Using equation 4.21, with v = vf at 0.045 bar

Pump work = -W34 = f (p4 – p3)

2
= 0.001 x ( 40 – 0.045) x 10
= 4.0 kJ/kg

Using equation 4.14

W12 = h1 – h2 = 2801 – 1839.3 = 961.7 kJ/kg

Then using equation 4.20
(h − h ) − (h − h )
 R = 1 2 4 3
(h −
1 h 3 ) − (h − h 3 )
4
( 961 ) 7 . ) 0 . 4 ( −
=
( 2801− 130 ) ) 0 . 4 ( −

= 0.359 or 35.9 %

Using equation 4.10

net work
Work ratio =
gross work

961.7 - 4.0
=
961.7

= 0.996

Using equation 4.24

3600
s.s.c. =
(h − h ) − (h − h )
1 2 4 3
3600
=
( 961 ) 7 . ) 0 . 4 ( −

= 3.76 kg/kW h

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