Case Studies in Thermal Engineering 25 (2021) 100929
Contents lists available at ScienceDirect
Case Studies in Thermal Engineering
journal homepage: http://www.elsevier.com/locate/csite
Exergy analysis and economic estimate of a novel solar and gas
combined system
Gang Wang a, *, Shukun Wang a, Tieliu Jiang a, Zeshao Chen b
a
b
School of Energy and Power Engineering, Northeast Electric Power University, Jilin, 132012, Jilin, China
School of Engineering Science, University of Science and Technology of China, Hefei, 230027, Anhui, China
H I G H L I G H T S
• A novel parabolic trough solar and gas combined (PSGC) system is proposed.
• Exergy evaluation of the PSGC system is conducted.
• Economic feasibility of the PSGC system is evaluated.
A R T I C L E I N F O
A B S T R A C T
Keywords:
PSGC
Solar thermal power
Parabolic-trough solar collector
Solar energy
Exergy analysis
In this paper, a novel parabolic-trough solar and gas combined (PSGC) system is proposed to
explore a new potential utilization approach of solar energy. The working principle of this PSGC
system is introduced. The operation behavior estimate and exergy analysis of the system are
conducted. The results show that this PSGC system has an output power of 96.1 MW and an
efficiency of 45.8%. The solar heat-to-electric efficiency is 21.6%. As the solar intensity augments,
the output power as well as the proportion of the solar energy increases. The maximum exergy
loss and minimum exergy efficiency both occur in the parabolic-trough-based solar direct steam
system (SDSS), which are 30.5 MW and 30.75%. The exergy loss and exergy efficiency of the SDSS
both increase as the solar intensity increases. With the solar intensity increased, for the steam
turbine (ST), the exergy loss in the high-pressure ST decreases, the exergy loss in the low-pressure
ST increases, and the exergy efficiency variations in the high- and low-pressure STs are both very
small. The economic analysis results indicate that the PSGC plant is economically feasible and its
net present value and internal rate of return are 447.94 million yuan and 19.5%, respectively.
1. Introduction
Among the new energy resources, solar energy is a very potential and developing energy source type [1,2]. Though solar energy is
clean and inexhaustible, its natures of fluctuating and intermittent have kept it away from large-scale utilizations to a certain degree.
This is a problem which must be solved for solar energy. The developments of energy storage [3] and multi-energy hybrid technologies
[4] are two effective approaches which can solve this problem. Many kinds of hybrid systems using solar energy exist, for instance, the
hybrid solar-coal system [5,6], solar and wind coupled system [7,8], integrated solar and gas combined cycle (ISCC) system [9,10],
hybrid solar and biomass system [11,12], solar and geothermal system [13,14], solar-wind-hydro system [15,16] and nuclear-solar
* Corresponding author.
E-mail address: kinggang009@163.com (G. Wang).
https://doi.org/10.1016/j.csite.2021.100929
Received 25 November 2020; Received in revised form 3 March 2021; Accepted 5 March 2021
Available online 7 March 2021
2214-157X/© 2021 The Author(s).
Published by Elsevier Ltd.
This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/).
Case Studies in Thermal Engineering 25 (2021) 100929
G. Wang et al.
Fig. 1. Diagrammatic sketch of the PSGC system design.
combined system [17,18]. Among the hybrid solar-based system mentioned above, several systems have been under experimental
evaluation or demonstration, which are the hybrid solar-coal system, ISCC system and solar and wind combined system.
In contrast with the pure gas and steam turbine (ST) combined system, many advantages of the ISCC systems have been indicated
[19,20]. For instance, the ISCC system can compensate the output power decrease of the gas and ST combined cycle when the ambient
conditions change. By using the ISCC system, the gas fuel as well as the greenhouse gas emission can also be reduced. Furthermore, the
complementary utilization of natural gas and solar energy can deepen the grid penetration of solar energy.
Many studies on the ISCC systems were launched by different researchers. An optimization study on an ISCC system using parabolic
trough solar collector was conducted by Li et al. [20]. By carrying out an economic analysis, the optimal solar multiple value was
obtained. Djimli et al. [21] launched a study on an ISCC system consisting of the solar chimney and a gas turbine (GT). The system is
designed for power generation. The thermodynamic analysis of the combined system as well as the economic investigation was
conducted. Rovira et al. [22] conducted a research work on two different ISCC system designs. The analysis results demonstrate that
one of the two ISCC system designs can have a solar heat-to-electricity efficiency up to approximately 50.0%. The thermodynamic and
economic behaviour evaluations of an ISCC system were launched by Ameri and Mohammadzadeh [23]. The influences of different
energy production methods for the ISCC system was investigated. Brodrick et al. [24] conducted a research work on an ISCC system.
The system was optimally designed and the economic evaluation for the ISCC system was also launched. Achour et al. [25] analyzed
the transient performance of the first ISCC units built in Algeria. The results indicate that the ISCC system can improve the power and
efficiency by 17% and 16.5% compared with the gas-steam turbine combined cycle (GTCC) system. Exergy analysis of an ISCC system
conducted by Ameri et al. [26] shows that the solar-powered auxiliary gas steam combined cycle system had a big advantage in
thermal performance.
For the ISCC systems studied, their heat recovery steam generators (HRSGs) all have relatively high exhaust gas temperatures.
Those lead to lower efficiencies of the HRSGs. It is foreseeable that the efficiency of the HRSG can be improved to a certain extent if part
of the heat in the end of the HRSG can be used in some way. In order to find a new potential utilization approach of solar energy and
reveal its feasibility, an innovative parabolic-trough-based solar and gas combined (PSGC) system is proposed in the current study. The
design method as well as the composition of the PSGC system is provided. The PSGC system is modeled. The operation behaviour
estimate and exergy analysis of the PSGC system are carried out under different conditions. Furthermore, the economic feasibility of
the PSGC system is preliminarily investigated.
2. Design of the PSGC system
Fig. 1 presents the layout of the PSGC system. The PSGC system mainly consists of two GTs, two HRSGs, one ST, a parabolic-troughbased solar direct steam system (SDSS) and three electric generators. Different from other ISCC designs, in this PSGC system, a hot
water heat exchanger (HWHX) is added at the end part of the HRSG, which is used to improve the boiler efficiency ηhrsg (see Point 4 in
Fig. 1). Due to the short operation cycle of GT, the GT shutdown frequently occurs. Contrarily, the ST has slower start-up and shutdown
2
Case Studies in Thermal Engineering 25 (2021) 100929
G. Wang et al.
Table 1
Parameters for the PSGC system modeling.
Components
Parameter
Value
GT
Rated electric power
Pressure ratio
Exhaust gas temperature
Mass flow rate of exhaust gas
Exhaust pressure
Inlet steam temperature
Inlet steam pressure
Internal efficiency
Parabolic-trough width
Optical efficiency
Inlet water temperatures/pressure
Outlet steam temperature/pressure
31.0 MW
18.0
546.0 ◦ C
88.0 kg∙s-1
0.005 MPa
500.0 ◦ C
5.0 MPa
0.9
5.7 m
75.0%
80.0 ◦ C/0.6 MPa
220.0 ◦ C/0.5 MPa
ST
SDSS
processes. Therefore, the gas and ST combined cycle of the PSGC system is chosen to be a two-to-one mode. Two HRSGs are driven by
two GTs. The two HRSGs mix their steam and after that, the mixed steam goes into one ST. In this way, one GT will still operate when
the other one has stopped its work. Thus, the ST can keep operating. This mode can improve the operational reliability of the PSGC
system.
As shown Fig. 1, the green solid line is the flow process of water and the red dash line is that of steam. The operating mode of the
PSGC system is relatively flexible. When the day time has adequate solar radiation, the parabolic-trough solar system will operate. If
the solar radiation is insufficient, only the gas and ST combined cycle part will operate. In the current study, the start-up DNI value for
the parabolic-trough solar system is assumed to be 400.0 W∙m-2.
Compared with other ISCC systems, the proposed PSGC system has a higher efficiency of HRSG. In contrast to concentrated solar
power systems, the PSGC system has no large-scale heat storage device but has a more flexible operating mode. The PSGC system can
operate either with or without the incident solar radiation.
For the PSGC system, the output electric power is recorded as Ppsgc, the real-time electric powers generated by the GTs and ST are
Pgt and Pst. If the electric power generated by the ST is recorded as Pst,0 when the parabolic-trough-based solar direct steam system is
not put into operation, the real-time electric power Ps contributed by the solar energy will be:
(1)
Ps = Ppsgc − Pgt − Pst,0
and the real-time electric power generated by the ST is:
(2)
Pst = Pst,0 + Ps
The energy efficiency ηpsgc of the PSGC system is defined as the ratio of the output electric power to the total input thermal power:
/(
)
(3)
ηpsgc = Ppsgc Qs + Qfuel
where Qs and Qfuel represent the thermal power provided for electricity production by the solar direct steam system and natural gas,
respectively.
The solar energy capacity proportion of the PSGC system can be characterized by the following parameter ks:
/
ks = Ps Ppsgc
(4)
For a component of the PSGC system, the exergy loss Ex,loss is:
N
∑
Ex,loss =
M
∑
Ex,in,i −
i=1
(5)
Ex,out,j
j=1
where Ex,in,i and Ex,out,j are the exergy values of the i-th line going into and j-th line going out of this component. Thus, the corre­
sponding exergy efficiency ηexe is:
/
ηexe = 1 − Ex,loss Qu
(6)
where Qu stands for different power values for different components.
3. Modeling of the PSGC system
For the design point of the PSGC system, the environmental temperature is 15.0 ◦ C, the solar intensity is 900.0 W∙m-2, the relative
air humidity is 60.0% and the atmosphere pressure is 0.1013 MPa. The intake and exhaust pressure losses of the GT are 9.96 mbar and
14.95 mbar, respectively.
The rated power of the PSGC system is 96.0 MW. The rated power of the gas and ST combined cycle is 87.0 MW. Thus, the electric
3
Case Studies in Thermal Engineering 25 (2021) 100929
G. Wang et al.
Fig. 2. Modeling of the PSGC system: 1—No.1 GT; 2—No.1 HRSG; 3—No.1 high pressure feedwater pump; 4—ST; 5—trough solar collector;
6—condenser; 7—condensate pump; 8—No.2 HRSG; 9—No.2 high pressure feedwater pump; 10—No.2 GT.
Table 2
Validation results of the gas and ST combined cycle.
Parameters
Units
Vd
Vs
Er
Total electric power
Power of GT
Power of ST
Exhaust gas temperature
High-pressure steam mass flow rate
High-pressure steam temperature
High-pressure steam pressure
Low-pressure steam mass flow rate
Low-pressure steam temperature
Low-pressure steam pressure
MW
MW
MW
◦
C
t∙h-1
◦
C
MPa
t∙h-1
◦
C
MPa
87.0
31.0
25.0
546.0
80.0
500.0
4.995
17.0
200.0
0.5
87.1
30.9
25.1
545.9
79.7
500.0
5.0
17.3
199.6
0.5
0.115%
0.323%
0.400%
0.018%
0.375%
–
0.100%
1.765%
0.200%
–
Table 3
Design point parameters of the PSGC system.
Parameters
Units
Results
Output power of the PSGC system (Ppsgc)
Electric power of the GT (Pgt)
Electric power of the ST (Pst)
Electric power provided by solar energy (Ps)
Energy efficiency of the PSGC system (ηpsgc)
GT efficiency (ηgt)
HRSG efficiency (ηhrsg)
Proportion of solar energy (ks)
Solar heat-to-electric efficiency
MW
MW
MW
MW
–
–
–
–
–
96.1
31.0
34.1
9.0
45.8%
37.4%
82.7%
9.4%
21.6%
power contributed by the parabolic-trough-based SDSS is 9.0 MW. The parabolic-trough collector and GT models are chosen to be the
Eurotrough 150 [27] and LM2500+G4 [28]. The HRSG is the horizontal, double-pressure, no re-burning and natural cycle type. The ST
is the double-cylinder type with no steam replenishment and extraction.
When the PSGC system is modeled, the Ebsilon program is utilized. Some typical parameters for the PSGC system modeling are
provided in Table 1. The simulation model of the PSGC system is presented in Fig. 2.
For the validation of the model established by using the Ebsilon, a comparison analysis between the design values and simulation
results of the gas and ST combined cycle is conducted. The comparison results are shown in Table 2, where Vd and Vs are the design
4
Case Studies in Thermal Engineering 25 (2021) 100929
G. Wang et al.
Fig. 3. Powers at different solar intensities.
Fig. 4. Efficiencies at different solar intensities.
Fig. 5. Proportion variation of solar energy at different solar intensities.
5
Case Studies in Thermal Engineering 25 (2021) 100929
G. Wang et al.
Table 4
Exergy estimate results of the PSGC system.
Components
Exergy loss/MW
Exergy efficiency/%
Parabolic-trough SDSS
High-pressure ST
Low-pressure ST
Generator for the ST
Condenser
High-pressure super-heater
High-pressure evaporator
High-pressure economizer
Low-pressure super-heater
Low-pressure evaporator
Condensate heater
HWHX
GT
30.466
2.338
2.921
0.504
4.159
0.579
1.696
0.514
0.03
0.261
0.508
0.104
7.036
30.75%
77.65%
88.09%
98.56%
95.61%
91.93%
91.54%
89.21%
88.28%
95.08%
89.1%
91.56%
92.22%
Fig. 6. Exergy loss and efficiency variations of the SDSS.
values and simulation results, and Er stands for the relative error. It can be concluded that the relative errors between the design and
simulation values are all small. The values of high-pressure steam temperature and low-pressure steam pressure are unchanged.
4. Results and discussions
4.1. Operation behaviour
According to the parameters presented in Table 1 and based on the simulation model built in Section 3, when the PSGC system
operates at the design condition, its behaviour is simulated and Table 3 shows the results. The results reveal that the power of the PSGC
system is 96.1 MW. The energy efficiency of the PSGC system is 45.8% and the solar heat-to-electric efficiency is 21.6%. The solar
energy capacity proportion of this PSGC system is 9.4%.
When the DNI augments from 400.0 W∙m-2 to 1000.0 W∙m-2, the operation behaviour of the PSGC system is investigated. The
simulation results are illustrated in Figs. 3–5. Fig. 3 illustrates the electric powers at different solar intensities. It can be seen that the
electric power of GT keeps settled as the operation mode of the GT is assumed to unchanged. The increase of input solar heat leads to
the increase of Ps. As a result, the powers of the ST and PSGC system both increase. Ppsgc is approximately 97.1 MW when the solar
intensity augments to 1000.0 W∙m-2.
Efficiency variations at different DNI conditions are presented in Fig. 4. The results indicate that when the solar intensity increases,
the GT efficiency keeps fixed, the HRSG efficiency increases and the energy efficiency of the PSGC system decreases. As the solar heatto-electric efficiency is lower than that of the gas and ST combined cycle, the increase of input solar heat will result in the decrease of
the overall energy efficiency.
Fig. 5 illustrates the proportion variation curve of solar energy at different solar intensities. It is obvious that the increase of solar
intensity can improve the solar energy capacity proportion of this PSGC system.
4.2. Exergy evaluation results
Based on the simulation model and Eqs. (5) and (6), the exergy evaluation of the PSGC system are carried out. The environmental
6
Case Studies in Thermal Engineering 25 (2021) 100929
G. Wang et al.
Fig. 7. Exergy loss and efficiency variations of the HWHX.
Fig. 8. Exergy loss variations of the ST.
Fig. 9. Exergy efficiency variations of the ST.
7
Case Studies in Thermal Engineering 25 (2021) 100929
G. Wang et al.
Table 5
Initial parameters for the economic analysis of the PSGC plant.
Parameters
Values
Parameters
Values
Specific investment of solar energy block
Specific investment of gas and ST combined cycle
Operating hours per year
OM costs of solar energy equipment
4851.0 yuan∙kW-1
5480.0 yuan∙kW-1
5500.0 h
2.0%
Annual interest rate
Loan proportion
Service life of the PSGC plant
OM costs of gas and ST combined cycle
7.0%
70.0%
30.0 years
3.0%
temperature is 15.0 ◦ C. Table 4 shows the exergy analysis results of some key components of the PSGC system under the design
condition. The results presented in Table 4 show that the maximum exergy loss and minimum exergy efficiency both occur in the solar
direct steam system. The corresponding exergy loss and efficiency are 30.5 MW and 30.75%. The GT also has a large exergy loss (7.0
MW) and its exergy efficiency is 92.22%.
For a varying solar intensity condition, the exergy evaluation of the PSGC system is also launched. The relevant results are illus­
trated in Figs. 6–9. As the operating mode of the GT is settled, the exergy parameters of the GT are basically unchanged when the solar
intensity changes. Fig. 6 presents the exergy loss and efficiency variations of the parabolic-trough solar direct steam system. The results
indicate that the exergy loss as well as the exergy efficiency of the solar direct steam system increases as the solar intensity augments.
The exergy efficiency of the solar direct steam system is approximately 31.39% when the DNI augments to 1000.0 W∙m-2.
Fig. 7 shows the exergy loss and efficiency variations of the HWHX. The results demonstrates that as the solar intensity augments,
for the HWHX, the exergy loss increases and the exergy efficiency decreases. In general, the exergy loss of the HWHX is relatively small.
When the solar intensity is 1000.0 W∙m-2, the exergy loss and efficiency of the HWHX are 0.117 MW and 91.21%.
The exergy loss and efficiency variations of the processes in high- and low-pressure steam turbines are presented in Figs. 8 and 9.
According to Fig. 8, as the solar intensity augments, the exergy loss in the high-pressure ST decreases, while that in the low-pressure ST
increases. When the DNI augments to 1000.0 W∙m-2, the exergy losses in the high- and low-pressure STs are 2.3 MW and 3.041 MW.
In Fig. 9, as the DNI augments from 400.0 W∙m-2 to 1000.0 W∙m-2, the exergy efficiencies in the high- and low-pressure STs both
increase, but the variations are both very small. When the DNI reaches 1000.0 W∙m-2, the exergy efficiencies in the high- and lowpressure STs are 77.69% and 88.13%.
4.3. Economic analysis results
A dynamic economic analysis is conducted for this PSGC system. The dynamic investment payback period Pback represents the time
required from the start of the project to the recovery of the project investment cost. It can be expressed as:
(7)
Pback = Gin / (INan − Can )
where Gin stands for the total project investment cost. INan and Can represent the annual income and annual operating costs, which can
be expressed below:
INan = Wan · ELCrate
(8)
Can = Fan + Co−
(9)
m
+ Aan
where Wan and ELCrate are the annual power generating capacity and electricity price. Fan represents the annual fuel costs of the PSGC
plant. Co-m stands for the annual operation and maintenance (OM) costs. Aan is the conversion value of annual project investment cost,
which is:
Aan = Gin ×
i(1 + i)n
(1 + i)n − 1
(10)
where i and n stand for the annual interest and technical economic analysis cycle of the PSGC plant, respectively.
The net present value Cnpv refers to the algebraic sum of the differences between the present values of cash inflow and outflow
during the project operation cycle, according to the benchmark discount rate within the industry or other set discount rate. A net
present value which is no less than 0 can be acceptable for the PSGC plant. Cnpv can be expressed as:
Cnpv =
n
∑
(INan − Can )t (1 + ic )−
(11)
t
t=0
where ic is the pre-set discount rate.
The internal rate of return iirr is the discount rate when the total present value of cost inflow is equal to that of cost outflow. When
the internal rate of return is equal or greater than the pre-set discount rate, the project can be feasible. The internal rate of return can be
calculated by using the equation below:
8
Case Studies in Thermal Engineering 25 (2021) 100929
G. Wang et al.
Table 6
Main economic indicators of the PSGC plant.
Indicators
Values
Total investment cost
Annual power generating capacity
Annual OM costs
Annual fuel costs
Conversion value of annual project investment cost
Dynamic investment payback period
Net present value
Internal rate of return
531.33 million yuan
4.90 million kWh
15.12 million yuan
229.90 million yuan
42.82 million yuan
5.1 years
447.94 million yuan
19.5%
n
∑
(INan − Can )t (1 + iirr )− t = 0
(12)
t=0
For the economic analysis of the PSGC system, the electricity prices of solar thermal power and gas-ST combined cycle are assumed
to be 1.15 yuan∙kWh-1 and 0.80 yuan∙kWh-1. The natural gas price is assumed to be 2.20 yuan∙Nm-3. Other relevant initial parameters
are presented in Table 5. When the pre-set discount rate is assumed to be 10.0%, based on Eqs. (7)-(12), the main technical economy
indicators of the PSGC plant are calculated and the results are shown in Table 6.
According to Table 6, the dynamic investment payback period of the PSGC plant is 5.1 years. The net present value is 447.94 million
yuan. The internal rate of return is approximately 19.5%, which is higher than the pre-set discount rate. Therefore, it can be
demonstrated that the PSGC plant can have good profitability and is economically feasible.
5. Conclusions
In the current study, a novel PSGC system is developed. The working principle as well as the design approach of the PSGC system is
given. The solar energy block is a parabolic-trough-based solar direct steam system. The gas and ST combined cycle is a two-to-one
type. The simulation model of the PSGC system is built based on the Ebsilon program. The operation behaviour estimate and
exergy analysis of the PSGC system are carried out under different conditions. The results show that the total power of the PSGC system
is 96.1 MW. The energy efficiency of the PSGC system is 45.8% and the solar heat-to-electric efficiency is 21.6%. The solar energy
capacity proportion of the PSGC system is 9.4%. As the solar intensity augments, the output power as well as the solar energy capacity
proportion increases. The exergy analysis results reveal that the maximum exergy loss and minimum exergy efficiency both occur in
the parabolic-trough solar direct steam system, which are 30.5 MW and 30.75%, respectively. The GT also has a large exergy loss (7.0
MW) and its exergy efficiency is 92.22%. The exergy loss as well as the exergy efficiency of the solar direct steam system increases as
the solar intensity augments. When the solar intensity increases, for the ST, the exergy loss in the high-pressure ST decreases, the
exergy loss in the low-pressure ST increases, and the exergy efficiencies in the high- and low-pressure STs both increase, but the
variations are both very small. The economic analysis results indicate that the dynamic investment payback period of the PSGC plant is
5.1 years. The net present value and internal rate of return of the PSGC plant are 447.94 million yuan and 19.5%, respectively. Thus,
the PSGC plant can have good profitability and is economically feasible.
Informed consent
Informed consent has been obtained from all individuals included in this study.
Author contributions
Gang Wang: Writing - original draft.
Shukun Wang: Writing - review & editing.
Tieliu Jiang: Writing - review & editing.
Zeshao Chen: Writing - review & editing.
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to
influence the work reported in this paper.
Acknowledgements
This work was supported by the Excellent Youth Foundation of Jilin Province of China (Grant No. 20190103062JH) and the Special
Project for the Outstanding Youth Cultivation of Jilin City of China (Grant No. 20190104126).
9
Case Studies in Thermal Engineering 25 (2021) 100929
G. Wang et al.
References
[1] G. Mokhtar, B. Boussad, S. Noureddine, A linear Fresnel reflector as a solar system for heating water: theoretical and experimental study, Case Stud. Therm. Eng.
8 (2016) 176–186.
[2] G. Wang, F. Wang, F. Shen, et al., Thermodynamic and optical analyses of a hybrid solar CPV/T system with high solar concentrating uniformity based on
spectral beam splitting technology, Energy 166 (2019) 256–266.
[3] H. Saini, R.P. Saini, J.S. Saini, A review on packed bed solar energy storage systems, Renew. Sustain. Energy Rev. 14 (2010) 1059–1069.
[4] T. Srinivas, B.V. Reddy, Hybrid solar–biomass power plant without energy storage, Case Stud. Therm. Eng. 2 (2014) 75–81.
[5] H. Hong, S. Peng, Y. Zhao, et al., A typical solar-coal hybrid power plant in China, Energy Procedia 49 (2014) 1777–1783.
[6] P. Shuo, W. Zhaoguo, H. Hui, et al., Exergy Evaluation of a typical 330 MW solar hybrid coal-fired power plant, Energy Convers. Manag. 85 (2014) 848–855.
[7] V. Khare, S. Nema, P. Baredar, Solar–wind hybrid renewable energy system: a review, Renew. Sustain. Energy Rev. 58 (2016) 23–33.
[8] F. Petrakopoulou, A. Robinson, M. Loizidou, Simulation and evaluation of a hybrid concentrating-solar and wind power plant for energy autonomy on islands,
Renew. Energy 96 (2016) 863–871.
[9] S. Peng, H. Hong, H. Jin, et al., An integrated solar thermal power system using intercooled gas turbine and Kalina cycle, Energy 44 (2012) 732–740.
[10] A.E. Elmohlawy, V.F. Ochkov, B.I. Kazandzhan, Thermal performance analysis of a concentrated solar power system (CSP) integrated with natural gas combined
cycle (NGCC) power plant, Case Stud. Therm. Eng. 14 (2019) 100458.
[11] U. Sahoo, R. Kumar, P.C. Pant, et al., Resource assessment for hybrid solar-biomass power plant and its thermodynamic evaluation in India, Sol. Energy 139
(2016) 47–57.
[12] J. Soares, A.C. Oliveira, Numerical simulation of a hybrid concentrated solar power/biomass mini power plant, Appl. Therm. Eng. 111 (2017) 1378–1386.
[13] J.M. Cardemil, F. Cortés, A. Díaz, et al., Thermodynamic evaluation of solar-geothermal hybrid power plants in northern Chile, Energy Convers. Manag. 123
(2016) 348–361.
[14] P.X. Jiang, F.Z. Zhang, R.N. Xu, Thermodynamic analysis of a solar–enhanced geothermal hybrid power plant using CO2 as working fluid, Appl. Therm. Eng. 116
(2017) 463–472.
[15] J. Schmidt, R. Cancella, A.O. Pereira, An optimal mix of solar PV, wind and hydro power for a low-carbon electricity supply in Brazil, Renew. Energy 85 (2016)
137–147.
[16] T. Ma, H. Yang, L. Lu, et al., Technical feasibility study on a standalone hybrid solar-wind system with pumped hydro storage for a remote island in Hong Kong,
Renew. Energy 69 (2014) 7–15.
[17] H.E. Garcia, J. Chen, J.S. Kim, et al., Dynamic performance analysis of two regional nuclear hybrid energy systems, Energy 107 (2016) 234–258.
[18] G. Wang, C. Wang, Z. Chen, et al., Design and performance evaluation of an innovative solar-nuclear complementarity power system using the S-CO2 Brayton
cycle, Energy 197 (2020) 117282.
[19] S. Pramanik, R.V. Ravikrishna, A review of concentrated solar power hybrid technologies, Appl. Therm. Eng. 127 (2017) 602–637.
[20] Y. Li, J. Yuan, Y. Yang, A study on solar multiple for an integrated solar combined cycle system with direct steam generation, Energy Procedia 61 (2014) 29–32.
[21] S. Djimli, A. Chaker, S. Ajib, et al., Studying the possibility of a combined hybrid solar chimney power plant with a gas turbine, Environ. Prog. Sustain. Energy
37 (2018) 1160–1168.
[22] A. Rovira, C. Sánchez, S. Fernández, et al., Integrated solar combined cycles using gas turbines with partial recuperation and solar integration at different
pressure levels. SOLARPACES, in: International Conference on Concentrating Solar Power and Chemical Energy Systems, AIP Publishing LLC, 2016, 2017.
[23] M. Ameri, M. Mohammadzadeh, Thermodynamic, thermoeconomic and life cycle assessment of a novel integrated solar combined cycle (ISCC) power plant,
Sustain. Energy Technol. Assess. 27 (2018) 192–205.
[24] P.G. Brodrick, A.R. Brandt, L.J. Durlofsky, Optimal design and operation of integrated solar combined cycles under emissions intensity constraints, Appl. Energy
226 (2018) 979–990.
[25] L. Achour, Omar Behar Bouharkat, Performance assessment of an ISCC in the southern of Algeria, Energy Rep. 4 (2018) 207–217.
[26] M. Ameri, M. Mohammadzadeh, Thermodynamic, thermoeconomic and life cycle assessment of a novel integrated solar combined cycle (ISCC) power plant,
Sustain. Energy Technol. Assess. 27 (2018) 192–205.
[27] E. Bellos, C. Tzivanidis, I. Daniil, et al., The impact of internal longitudinal fins in parabolic trough collectors operating with gases, Energy Convers. Manag. 135
(2017) 35–54.
[28] https://www.ge.com/power/gas/gas-turbines/lm2500.
Nomenclature
Aan: conversion value of annual project investment cost (yuan)
Can: annual operating costs (yuan)
Cnpv: net present value (yuan)
Ex,loss: exergy loss (MW)
ks: proportion of solar energy (-)
Gin: total project investment cost (yuan)
iirr: internal rate of return (%)
INan: annual income (yuan)
Pback: dynamic investment payback period (a)
Pgt: electric power generated by the gas turbine (MW)
Ppsgc: output electric power of the PSGC system (MW)
Ps: electric power contributed by the solar energy (MW)
Pst: electric power generated by the steam turbine (MW)
Qs: thermal power contributed by solar energy (MW)
Qfuel: thermal power contributed by natural gas (MW)Greek symbols
ηexe: exergy efficiency (-)
ηgt: efficiency of gas turbine (-)
ηhrsg: efficiency of HRSG (-)
ηpsgc: energy efficiency of the PSGC system (-)
ηst: efficiency of steam turbine (-)Subscripts
an: annual
DNI: direct normal irradiance
exe: exergy
gt: gas turbine
psgc: parabolic-trough solar and gas combined
st: steam turbineAbbreviation
GT: gas turbine
HRSG: heat recovery steam generator
10
Case Studies in Thermal Engineering 25 (2021) 100929
G. Wang et al.
HWHX: hot water heat exchanger
SDSS: solar direct steam system
ST: steam turbine
PSGC: parabolic-trough-based solar and gas combined
11