scholarly journals Optimization of a decoupled combined cycle gas turbine integrated in a particle receiver solar power plant

Author(s):  
Benoît Valentin ◽  
Frédéric Siros ◽  
Jean-Florian Brau
Author(s):  
R. Chacartegui ◽  
D. Sa´nchez ◽  
F. Jime´nez-Espadafor ◽  
A. Mun˜oz ◽  
T. Sa´nchez

The development of high efficiency solar power plants based on gas turbine technology presents two problems, both of them directly associated with the solar power plant receiver design and the power plant size: lower turbine intake temperature and higher pressure drops in heat exchangers than in a conventional gas turbine. To partially solve these problems, different configurations of combined cycles composed of a closed cycle carbon dioxide gas turbine as topping cycle have been analyzed. The main advantage of the Brayton carbon dioxide cycle is its high net shaft work to expansion work ratio, in the range of 0.7–0.85 at supercritical compressor intake pressures, which is very close to that of the Rankine cycle. This feature will reduce the negative effects of pressure drops and will be also very interesting for cycles with moderate turbine inlet temperature (800–1000 K). Intercooling and reheat options are also considered. Furthermore, different working fluids have been analyzed for the bottoming cycle, seeking the best performance of the combined cycle in the ranges of temperatures considered.


Author(s):  
B. Becker ◽  
H. H. Finckh ◽  
R. Meyer-Pittroff

In gas-cooled solar power plants the radiant energy of the sun is transferred to the cycle fluid in a cavity type solar receiver and converted into electric energy by means of a combined gas and steam turbine cycle incorporating a waste heat steam generator. The design and optimization of the energy conversion system in accordance with solar-specific considerations are described with particular regard to the gas turbine. In designing the energy conversion system several variants on the combined cycle with waste heat steam generator are investigated and special measures for the improvement of the cycle efficiency, such as the refinement of the steam process through the addition of pressure stages are introduced. It is demonstrated that the solar power plant meets the requirements both for straight solar and constant load operation with fossil fuel substitution. In order to establish the possibilities of attaining high part-load efficiencies in straight solar operation, two modes, variable and constant speed of the gas turbine, are compared with one another.


1982 ◽  
Vol 104 (2) ◽  
pp. 330-340 ◽  
Author(s):  
B. Becker ◽  
H. H. Finckh ◽  
R. Meyer-Pittroff

In gas-cooled solar power plants the radiant energy of the sun is transferred to the cycle fluid in a cavity type solar receiver and converted into electric energy by means of a combined gas and steam turbine cycle incorporating a waste heat steam generator. The design and optimization of the energy conversion system in accordance with solar-specific considerations are described with particular regard to the gas turbine. In designing the energy conversion system several variants on the combined cycle with waste heat steam generator are investigated and special measures for the improvement of the cycle efficiency, such as the refinement of the steam process through the addition of pressure stages are introduced. It is demonstrated that the solar power plant meets the requirements both for straight solar and constant load operation with fossil fuel substitution. In order to establish the possibilities of attaining high part-load efficiencies in straight solar operation, two modes, variable and constant speed of the gas turbine, are compared with one another.


Author(s):  
Rafael Guédez ◽  
James Spelling ◽  
Björn Laumert

The present work deals with the thermoeconomic analysis of an innovative combined power cycle consisting of a molten-salt solar tower power plant with storage supported by additional heat provided from the exhaust of a topping gas-turbine unit. A detailed dynamic model has been elaborated using an in house simulation tool that simultaneously encompasses meteorological, demand and price data. A wide range of possible designs are evaluated in order to show the trade-offs between the objectives of achieving sustainable and economically competitive designs. Results show that optimal designs of the novel concept are a promising cost-effective hybrid option that can successfully fulfill both the roles of a gas peaker plant and a baseload solar power plant in a more effective manner. Moreover, designs are also compared against conventional combined cycle gas turbine power plants and it is shown that, under specific peaking operating strategies, the innovative concept can not only perform better from an environmental standpoint but also economically.


Author(s):  
Rafael Guédez ◽  
James Spelling ◽  
Björn Laumert

The present work deals with the thermo-economic analysis of an innovative combined power cycle consisting of a molten-salt solar tower power plant with storage supported by additional heat provided from the exhaust of a topping gas-turbine unit. A detailed dynamic model has been elaborated using an in house simulation tool that simultaneously encompasses meteorological, demand and price data. A wide range of possible designs are evaluated in order to show the trade-offs between the objectives of achieving sustainable and economically competitive designs. Results show that optimal designs of the novel concept are a promising cost-effective hybrid option that can successfully fulfill both the roles of a gas peaker plant and a baseload solar power plant in a more effective manner. Moreover, designs are also compared against conventional combined cycle gas turbine (CCGT) power plants and it is shown that, under specific peaking operating strategies (P-OSs), the innovative concept cannot only perform better from an environmental standpoint but also economically.


2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Erik Pihl ◽  
James Spelling ◽  
Filip Johnsson

A thermo-economic optimization model of an integrated solar combined-cycle (ISCC) has been developed to evaluate the performance of an existing combined-cycle gas turbine (CCGT) plant when retrofitted with solar trough collectors. The model employs evolutionary algorithms to assess the optimal performance and cost of the power plant. To define the trade-offs required for maximizing gains and minimizing costs (and to identify ‘optimal’ hybridization schemes), two conflicting objectives were considered, namely, minimum required investment and maximum net present value (NPV). Optimization was performed for various feed-in tariff (FIT) regimes, with tariff levels that were either fixed or that varied with electricity pool prices. It was found that for the given combined-cycle power plant design, only small annual solar shares (∼1.2% annual share, 4% of installed capacity) could be achieved by retrofitting. The integrated solar combined-cycle design has optimal thermal storage capacities that are several times smaller than those of the corresponding solar-only design. Even with strong incentives to shift the load to periods in which the prices are higher, investment in storage capacity was not promoted. Nevertheless, the levelized costs of the additional solar-generated electricity are as low as 10 c€/kWh, compared to the 17–19 c€/kWh achieved for a reference, nonhybridized, “solar-only” concentrating solar power plant optimized with the same tools and cost dataset. The main reasons for the lower cost of the integrated solar combined-cycle power plant are improved solar-to-electric efficiency and the lower level of required investment in the steam cycle. The retrofitting of combined-cycle gas turbine plants to integrated solar combined-cycle plants with parabolic troughs represents a viable option to achieve relatively low-cost capacity expansion and strong knowledge building regarding concentrating solar power.


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