An Efficient Parabolic Dish Engine Based On Rankine Cycle
An Efficient Parabolic Dish Engine Based On Rankine Cycle
An Efficient Parabolic Dish Engine Based On Rankine Cycle
1. Introduction
Solar energy concentration is an interesting option to
increase the energy density of the solar radiation resulting
in the possibility to use absorbers with small surfaces.
Since the objective is to convert the solar energy into
useful work, the theory suggests that it can be done more
efficiently the higher the temperature is.
The aim of this work is to capture solar radiation and
convert it into electric power via solar thermal energy. The
capture of solar radiation and conversion of it into solar
thermal energy involves the use of solar receivers. In order
to improve these solar receivers, some studies have been
carried out using computer models and experimental data
[1], [2], [3]. A lot of research has been carried out on
designing new receivers or improving the performance of
existing ones [4; 5], and on understanding factors that
m&
Cp
To
Ti
th =
QU m& C P (To Ti )
=
QS
AAp C E S
(3)
PDC
0,5
100
0,4
1000
5000
receiver
HEX
0,3
0,2
0,1
0
500
1000
1500
2000
2500
3000
which
(3)
(3b)
R =
Wi Wo Wn Qi Qo
=
Qi
Qi
Qi
(4)
Qi
Qi
Vaporiser
Wo
2
Wo
Wi
Wi
Condenser
1 Qo
S
(a)
Qo
(4x)
(2x)
(2)
(1) condenser
regenerator
Fig. 5. Structure of a double turbine Rankine cycle
4.
(b)
Fig. 3. Basic ultra-supercritical RC: (a) the T-S diagram. (b), the
basic plant structure
Ethane
1
2
3
3a
3b
4
4x
2x
T(K)
300
350
675
604
675
613,6
370
561
PDC
G
receiver
HEX
Table III. State point values for the RC operating with water
H2O
1
2
3
3a
3b
4
T(K)
320
320,2
700
445,8
700
369,7
h(kJ/kg)
196,18
199,8
3277,5
2799,51
3329,5
2679,88
S(kJ/kg-K)
0,66285
0,6628
6,8632
6,9856
7,9271
8,1329
p(bar)
0,19
40
40
4,5
4,5
0,19
15
10
Ammonia
Water
4000
3500
3000
2500
Qi
2000
Qo
1500
1000
500
0
Water
working fluids
Fig. 6. Specific input heat, output heat and work for the RC
The specific input heat flow rate, output heat flow rate and
specific work carried out by the Rakine cycle operating
with the mentioned working fluids is shown in figure 6. In
figure 7 it is depicted the thermal efficiency of the Rankine
cycle for every working fluid. In any case the thermal
efficiency is greater than 30%.
5.
Serie1
working fluid
Ammonia
25
20
Ethane
Ethane
35
30
5
0
Qi
Qo
W
Eff
efficiency (%)
The Table III shows the state point values for the RC
operating with water.
45
40
Conclusions
References
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