1.

0 OBJECTIVE
1.1 To obtain a relationship between the pressure and temperature of saturated steam,
in equilibrium with water, at all pressure between atmospheric and 9 bars
1.2 To compare between calculated values from experiment data to the data obtained
from steam table for vfg and hfg .
2.0 THEORY
Thermodynamics is defined as a study related to the transfer of heat and work between a
system and the surrounding, undergoing a process causing any of the properties of the
system change.
An ideal gas obeys the equation of state that relates the pressure, specific volume or
density, and absolute temperature with the mass of molecule and the gas constant, R.
mRT
PV =
M

dT T ( v g v f ) T v g
= =
dP hfg h fg

Where
Vf = specific volume of water
Vg = specific volume of steam
hf = enthalpy of water
hg = enthalpy of steam
hfg = enthalpy of water
3.0 EQUIPMENT / APPARATUS
- Marcet Boiler

4.0 PROCEDURE
4.1 The hand valve of the Marcet Boiler was open.
4.2 Switch on the power supply and the heater.
4.3 Wait and observe the steam release from the hand valve.
4.4 After steam release about 1 minute and then close the hand valve.
4.5 The heating process until the pressure gauge reaches the maximum reading of 9.0.
4.6 During the heating process, pressure and temperature was increased.
 4.7 Take both the temperature reading started at 1.0 bar.
4.8 Continue the reading until 9.0 bars.
4.9 Once pressure increase until 9.0 bar, the heater will be switch OFF.

5.0 CALCULATION & ANALYSIS

5.1 Graph of Temperature (C) vs Absolute Pressure (bar).

Graph of Temperature () vs Absolute Pressure (bar)

200

T 180
e
160
m
p 140
e
r 120
a 100
t
u 80
r
e 60
40
(
20
)
0
0 1 2 3 4 5 6 7 8 9 10

Absolute Pressure (bar)

5.2 The slope of dT and dP at data between pressure 5 to 6 bar in graph was measured
and compare with the theoretical result.
157.2150.1
Measured slope = 6.05.0

= 7.1
( 0.0728+ 0.0677 )100
Theoretical Result = 2

= 7.0

5.3 The Theoretical calculation starting from 7 to 9 bars.

- Calculation of Steam Specific Volume, vg starting from 7 to 9 bars.

Absolute Temperature
Steam Specific Volume, vg (m3/kg)
Pressure (bar) Reading (C)
2065.6v g 165.0163.4
=
2065.62082.0 165.0160.0
7.0 163.4
v g=2070.8
 2048.8v g 170.0166.2
=
2048.82065.6 170.0165.0
7.5 166.2
v g=2061.6

2048.8v g 170.0168.9
=
2048.82065.6 170.0165.0
8.0 168.9
v g=2052.5

2031.7v g 175.0171.5
=
2031.72048.8 175.0170.0
8.5 171.5
v g=2043.7

2031.7v g 175.0173.9
=
2031.72048.8 175.0170.0
9.0 173.9
v g=2035.5

- Calculation of Enthalpy of Evaporation, hfg starting from 7 to 9 bars.

Absolute Temperature
Enthalpy of evaporation, hfg (kj/kg)
Pressure (bar) Reading (C)
0.2724v g 165.0163.4
=
0.27240.3068 165.0160.0
7.0 163.4
v g=0.2834

0.2426v g 170.0166.2
=
0.24260.2724 170.0165.0
7.5 166.2
v g=0.2653

0.2426v g 170.0168.9
=
0.24260.2724 170.0165.0
8.0 168.9
v g=0.2492

0.2166v g 175.0171.5
=
0.21660.2426 175.0170.0
8.5 171.5
v g=0.2348

0.2166v g 175.0173.9
=
0.21660.2426 175.0170.0
9.0 173.9
v g=0.2223
 - Calculation of Theoretical Result starting from 7 to 9 bars.

Absolute Steam Specific Enthalpy of

Temperature
Pressure Volume, vg evaporation, Theoretical Result
Reading (K) 3
(bar) (m /kg) hfg (kj/kg)
436.40.2834
7.0 436.4 0.2834 2070.8
=0.0597
2070.8
439.20.2653
7.5 439.2 0.2653 2061.6
=0.0565
2061.6
441.90.2492
8.0 441.9 0.2492 2052.5
=0.0537
2052.5
444.50.2348
8.5 444.5 0.2348 2043.7
=0.0511
2043.7
446.90.2223
9.0 446.9 0.2223 2035.5
=0.0488
2035.5
 6.0 DATA RESULTS

Experimental Theory
Data(Experimental) Result Data(Steam Table) Result
Absolut Steam Calculated
Enthalpy of
Temperature Pressure Temperature
e Measured Specific Slope
Evaporation
Reading, T Difference Difference, K (m3 /kg)
Pressure Slope, K/bar Volume, Vg , hfg
(K) , dP (bar) dT (K)
(kj/kg)
(kj/kg )
, P (bar) (m3/kg)
1.0 367.8 - - - 1.9959 2270.1 0.3234
1.5 380.9 0.5 13.1 26.2 1.2973 2235.3 0.2211
2.0 390.4 0.5 9.5 19.0 0.9666 2209.3 0.1708
2.5 397.8 0.5 7.4 18.8 0.7750 2188.7 0.1409
3.0 404.3 0.5 6.5 13.0 0.6456 2169.9 0.1203
3.5 409.9 0.5 5.6 11.2 0.5539 2153.5 0.1054
4.0 414.8 0.5 4.9 9.8 0.4860 2138.9 0.0943
4.5 419 0.5 4.2 8.4 0.4353 2126.1 0.0858
5.0 423.1 0.5 4.1 8.2 0.3916 2113.5 0.0784
5.5 426.7 0.5 3.6 7.2 0.3584 2102.1 0.0728
6.0 430.2 0.5 3.5 7.0 0.3290 2091.0 0.0677
6.5 433.4 0.5 3.2 6.4 0.3041 2080.7 0.0633
7.0 436.4 0.5 3.0 6.0 0.2834 2070.8 0.0597
7.5 439.2 0.5 2.8 5.6 0.2653 2061.6 0.0565
8.0 441.9 0.5 2.7 5.4 0.2492 2052.5 0.0537
8.5 444.5 0.5 2.6 5.2 0.2348 2043.7 0.0511
9.0 446.9 0.5 2.4 4.8 0.2223 2035.5 0.0488
Percentage error between experimental result and theoretical result.

Absolute Pressure, P Calculated Slope

Measured Slope, K/bar Percentage Error, %
(bar) K/kPa K/bar
1.0 - 0.3234 32.34 -
1.5 26.2 0.2211 22.11 18.50
2.0 19.0 0.1708 17.08 11.24
2.5 18.8 0.1409 14.09 33.43
3.0 13.0 0.1203 12.03 8.06
3.5 11.2 0.1054 10.54 6.26
4.0 9.8 0.0943 9.43 3.92
4.5 8.4 0.0858 8.58 2.10
5.0 8.2 0.0784 7.84 4.59
5.5 7.2 0.0728 7.28 1.10
6.0 7.0 0.0677 6.77 3.40
6.5 6.4 0.0633 6.33 1.11
7.0 6.0 0.0597 5.97 0.50
7.5 5.6 0.0565 5.65 0.88
8.0 5.4 0.0537 5.37 0.56
8.5 5.2 0.0511 5.11 1.76
9.0 4.8 0.0488 4.88 1.64
7.0 DISCUSSION AND QUESTIONS
7.1 Briefly discuss the experimental results.
From the experiment, the data obtained shown that the higher the pressure, the smaller
the increase of temperature.
7.2 Why do we need to release the air/gas from the equipment before the experiment?
It is necessary to release the air/gas from the boiler before the experiment as this could
affect the accuracy of the experimental results.
7.3 Compare the experimental result with theoretical result. Give your comments.
The percentage error between experimental result and theoretical result is about 0.5 to
33.43%. This is because there might be some error between the actual and ideal value
that we obtained. Those error may be the stability of materials and the accuracy of the
measurement reading.
7.4 Define the relationship between pressure and temperature.
Based on the Graph of Temperature (C) vs Absolute Pressure (bar), the absolute
pressure is directly proportional to the temperature while there is a small deviation
between the experimental slope and the theoretical slope.
7.5 If we increase the pressure, what will happen to the temperature?
The temperature will slightly increase if we increase the pressure of Marcet boiler.

8.0 CONCLUSION
From the experiment, the relationship between pressure and temperature is found to
be directly proportional. Comparison between the theoretical slope and the experimental
slope from the experiment showed a small deviation between them because of certain
errors. The percentage of error ranged from 0.5% to 33.43% which can validate this
experiment.
The experiment can be consider successful but still can improve the result of the
experiment by repeating the experiment and taking the average value or some insulation
materials were kept on the Marcet boiler to reduce heat loss so that the experiment could
be more accurate.