Thermoeconomic Analysis of Combined Cycle Coupled With Parabolic Trough Solar Plant

Author(s):  
M. D. Duran ◽  
E. A. Rincón ◽  
I. Martínez ◽  
A. Lentz

Parabolic trough technology is currently one of the most extended solar thermal systems for the production of electricity. This paper describes a thermo-economic study of an integrated, combined-cycle parabolic trough power plant. The parabolic trough plant is considered an economizer or a superheater of the HRSG (heat recovery steam generator). The main objective is to obtain the optimum design of the different sections of the boiler and the size of the parabolic field. The configurations analyzed are two pressure levels with and without a reheater. A Euro Trough (ET) concentrator was used in this study, the working fluid being water with direct steam generation. There will be no problem with the evaporation in the absorber, since the solar plant will be the economizer of the HRSG and an approach point greater than 3°C is considered. The methodology applied for the optimization is Genetic Algorithms. This methodology was employed in previous works developed by the authors and yielded good results. So that method is applied to the configurations analyzed but including the parabolic trough plant. As a result, a thermoeconomic optimum design of a parabolic trough plant used as the section of the HRSG is obtained. The results show that the solar field increases the power and efficiency of the combined-cycle plant during the operation and makes it less susceptible to load variations.

Author(s):  
Dolores Duran ◽  
Rafael Almanza ◽  
Ivan Martínez

This work shows the study of different configurations of integrated solar combined cycle (ISCC) parabolic-trough power plant with Direct Steam Generation (DSG). This paper is a sequel of previous works (Duran), but in this case six different configurations are analyzed: two pressure level without reheater (2P), 2P considering the solar field the high pressure economizer of the heat recovery steam generator, 2P considering the solar field the low pressure superheater, two pressure level with reheater (2PR), 2PR considering the solar field the low pressure superheater, 2PR considering the solar field the high pressure economizer. The main objective is to achieve the thermoeconomic optimization (based on Thermodynamic 1st. Law) of the HRSG including the solar field, to determine the optimal design parameters of both systems. It is applied a genetic algorithm (GA) methodology employed in previous works for the optimization of combined cycle power plants. Also, a sensitivity analysis with respect to the variation of solar radiation is done for the configurations that yield better results. As a result it would be obtained the optimal parameters of the HRSG and the optimal solar energy contribution for the configurations analyzed.


Author(s):  
Bruce Kelly ◽  
Ulf Herrmann ◽  
Mary Jane Hale

Abstract The integrated solar plant concept was initially proposed by Luz Solar International [1] as a means of integrating a parabolic trough solar plant with modern combined cycle power plants. An integrated plant consists of a conventional combined cycle plant, a solar collector field, and a solar steam generator. During sunny periods, feedwater is withdrawn from the combined cycle plant heat recovery steam generator, and converted to saturated steam in the solar steam generator. The saturated steam is returned to the heat recovery steam generator, and the combined fossil and solar steam flows are superheated in the heat recovery steam generator. The increased steam flow rate provides an increase in the output of the Rankine cycle. During cloudy periods and at night, the integrated plant operates as a conventional combined cycle facility. Two studies on integrated plant designs using a General Electric Frame 7(FA) gas turbine and a three pressure heat recovery steam generator are currently being conducted by the authors. Preliminary results include the following items: 1) the most efficient use of solar thermal energy is the production of high pressure saturated steam for addition to the heat recovery steam generator; 2) the quantity of high pressure steam generation duty which can be transferred from the heat recovery steam generator to the solar steam generator is limited; thus, the maximum practical solar contribution is also reasonably well defined; 3) small annual solar thermal contributions to an integrated plant can be converted to electric energy at a higher efficiency than a solar-only parabolic trough plant, and can also raise the overall thermal-to-electric conversion efficiency in the Rankine cycle; and 4) annual solar contributions up to 12 percent in an integrated plant should offer economic advantages over a conventional solar-only parabolic trough power plant.


Author(s):  
Ennio Macchi ◽  
Giampaolo Manzolini ◽  
Paolo Silva

The role of renewable energies and in particular solar energy could be fundamental in future scenarios of worldwide increase of energy demand: thermodynamic solar energy can play an important role in country with high solar radiation. This paper discusses the development and testing of an innovative code for the prediction of thermodynamic performances at nominal conditions and the estimation of costs of the whole plant, for different parabolic trough solar fields. The code allows a preliminary design of the solar field lay-out, the sizing of the main components of the plant and the optimization of the steam cycle. The code, named PATTO (PArabolic Trough Thermodynamic Optimization), allows to separately calculate the thermal efficiency of (i) parabolic trough systems in commerce as well as (ii) combination of components of various commercial systems, in order to exploit different technology solutions: combination of mirrors, receivers and supports. Using the selected parabolic troughs, the plant configuration is then completed by connecting pipes, heat exchangers, the steam cycle, and storage tanks. The code is also flexible in terms of working fluid, temperature and pressure range. Regarding the power block, a conventional steam cycle with super-heater and re-heater sections and up to seven regenerative bleedings is adopted. It is possible to use also simpler configuration as without re-heater or with less regenerative bleedings. Moreover, thanks to simple or sophisticated economic correlations depending on available data, the code calculates the overall investment cost for the considered solar field and the power block. The code performs steady state analysis at nominal conditions, while future developments are planned regarding part load analysis and transient simulations. The model is tested towards real applications and reference values found in literature; in particular, focusing on SEGS VI plant in the USA. Detailed results showing code potentiality, are presented in terms of solar field and power block energy balances, plant auxiliaries, piping and economic analysis.


2014 ◽  
Vol 492 ◽  
pp. 568-573 ◽  
Author(s):  
Yinka Sofihullahi Sanusi ◽  
Palanichamy Gandhidasan ◽  
Esmail M.A. Mokheimer

Saudi Arabia is blessed with abundant solar energywhichcan be use to meet its ever increasing power requirement. In this regard, the energy analysis and plant performance of integrated solar combined cycle (ISCC) plant with direct steam generation (DSG) was carried out for Dhahran, Saudi Arabia using four representative months of March, June, September and December. The plant consists of 180MW conventional gas turbine plant and two steam turbines of 80MW and 60MW powered by the solar field and gas turbine exhaust. With high insolation during the summer month of June the plant can achieve up to 25% of solar fraction with ISCC plant efficiency of 45% as compared to gas turbine base of 38%.This can however be improved by increasing the number of collectors or/and the use of auxiliary heater .


Author(s):  
M. D. Duran ◽  
E. A. Rinco´n ◽  
M. Sa´nchez

This work describes the thermoeconomic study of an integrated combined cycle parabolic trough power plant. The parabolic trough plant will economize boiler activity, and thus the thermoeconomic optimization of the configuration of the boiler, including the parabolic trough plant, will be achieved. The objective is to obtain the optimum design parameters for the boiler and the size of the parabolic field. The proposal is to apply the methodology employed by Duran [1] and Valde´s et. al. [2], but with the inclusion of the parabolic trough plant into the optimization problem. It is important to point out that the optimization model be applied to a single pressure level configuration. For future works, it is proposed that the same model be applied to different configurations of integrated combined cycle solar power plants. As a result the optimum thermoeconomic design will be obtained for a parabolic trough plant used to economize the HRSG.


2020 ◽  
Vol 143 (3) ◽  
Author(s):  
C. V. Chachin Vishal ◽  
Jayaraj Krishnan ◽  
G. Venkatesan ◽  
V. Samson Packiaraj Raphael ◽  
Purnima Jalihal

Abstract Conventional desalination technologies like multi stage flashing, multi-effect desalination (MED) using steam as motive fluid can be made sustainable by obtaining the motive steam from solar thermal systems. In this study, a transient simulation has been performed to determine the dissimilitude in pressure drop and dryness fraction, of working fluid in absorber tube due to variation in solar irradiance. A one-dimensional (1D) mathematical model has been developed using matlab for assessing the thermal performance and heat transfer characteristics of a direct steam generating (DSG) parabolic trough collector (PTC) system. It was observed that maximum pressure drop does not occur at maximum quality indicating the working conditions impair the system performance. The developed model was used to overcome this by varying both pressure and mass flowrate of working fluid in accordance to the radiation, results indicated reduction in pressure drop during the same time period for the same exit quality.


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