Optimization of an integrated solar combined cycle

Energy Procedia, 2015

A solar closed air Brayton cycle, with rated power of 50 MW, was considered. The system is composed of a concentrating solar tower with volumetric receiver, an intercooling and regenerating gas turbine and an evaporative tower cooling system. The characteristic feature of the system is a control strategy able to adjust the plant in a large range of load, maintaining net electric conversion efficiency almost constant. The concentrating solar power (CSP) plant operates without adding fuel and can heat air up to a maximum temperature of 850 °C, at the solar tower outlet. The numerical analysis was performed by SAM for the solar tower and by Thermoflex © for the assessment of the performance of the whole system. The thermal energy input was calculated on the basis of the DNI of the TMY from Seville. Results show an electricity production greater than 75GWh per year, with a significant sparing fossil fuel consumption and avoided CO 2 emissions.

2018

Parabolic trough power plants have been developed in the integrated solar combined cycle system (ISCCS) and the direct steam generation (DSG) ,each concept has their configuration due to solar energy combination .The technology for the Solar Aided Power Generation (SAPG) is appeared for optimizing this combination in solar contribution to cycle efficiency. The target of this work is to evaluate the thermodynamic performance on solar hybrid power plants system for ISCCS and DSG concepts, in comparison for a solar to electricity efficiency. The Solar Aided Power Generation is proposed to assuming the solar contribution with evaluation method, for to calculate the generation share of the solar power system in each concept. The study shows that the DSG concept is the best hybrid system to solar-electric efficiency .Further results obtained indicate that solar contribution increase to the DSG concept proposed , in the best extraction of solar thermal for to preheat the feed water heater....

In conventional thermal power plant as we know co 2 emission is main disadvantages and it effect to the environment and cost of fossil fuel is also higher, so it is required to develop technology which reduce the emission of co 2 and reduce fuel cost , so technology start diverting on the way to the non-conventional or renewable energy sources which is widely available and also not effect to the environment so this paper is present based on main source of energy that is solar energy .with camper to other non-conventional power plant solar power plant is more efficient. By use of solar thermal combine power plant we can reduce the use of fossil fuel and its is economical process and by use of this combination we can reduce co 2 emission it is also called solar hybrid power plant KEY WORDS Solar thermal power plant, renewable source of energy, solar pond, solar chimney

Renewable Energy, 2012

This article deals with comparative energy and exergetic analysis for evaluation of natural gas fired combined cycle power plant and solar concentrator aided (feed water heating and low pressure steam generation options) natural gas fired combined cycle power plant. Heat Transfer analysis of Linear Fresnel reflecting solar concentrator (LFRSC) is used to predict the effect of focal distance and width of reflector upon the reflecting surface area. Performance analysis of LFRSC with energetic and exergetic methods and the effect, of concentration ratio and inlet temperature of the fluid is carried out to determine, overall heat loss coefficient of the circular evacuated tube absorber at different receiver temperatures. An instantaneous increase in power generation capacity of about 10% is observed by substituting solar thermal energy for feed water heater and low pressure steam generation. It is observed that the utilization of solar energy for feed water heating and low pressure steam generation is more effective based on exergetic analysis rather than energetic analysis. Furthermore, for a solar aided feed water heating and low pressure steam generation, it is found that the land area requirement is 7 ha/MW for large scale solar thermal storage system to run the plant for 24 h.

International Journal of Renewable Energy Research, 2014

The renewable resource, mainly the solar energy, can be used to produce electric energy on a large scale in solar thermal power stations, which concentrate sunlight at temperatures which range between 200° to 1200° C and even more. This paper presents a conceptual configuration of a solar powered combined cycle power plant with a topping air Brayton cycle and a bottoming steam Rankine cycle. The conventional gas turbine (GT) combustion chamber is replaced by a high-temperature solar thermal air heating system. During the daytime, a part of the exhaust air from the GT is bypassed to produce superheated steam in the heat recovery steam generator (HRSG), which in turn runs a steam turbine and the remaining exhaust air from GT is utilized to charging molten salt, which acts as a storage medium. The heat energy of the molten salt is utilized to generate steam for 4 hours in another HRSG, when sunlight is not available. From the thermodynamic analysis, it is found that for the base case GT pressure ratio of 4, power obtained from the GT block is 1.75 MW, while total power obtained from the combined cycle is 2.28 MW. The overall thermal efficiency of the combined cycle at this pressure ratio is 25.39%. The pressure ratio of the gas turbine has been varied from 2 to 20 and the optimum pressure ratio has been found out where total power output of the combined cycle plant is maximum.

Energy Procedia, 2015

The increasing penetration of low-carbon technologies and enhancements in fossil-fuelled power plants efficiency are some of the most important and up to date research topics. Renewable energy, in particular solar, has the potential of meeting the world energy needs while addressing environmental concerns, but technological advances in renewable energy electricity production are necessary to become competitive with conventional technologies. New opportunities to increase the penetration of renewables energies, smoothing out renewables variability and intermittency problems, come out from the hybridization concept. Hybrid renewable-fossil fuel systems join the advantages of both renewable energies and programmable devices. Among all the renewable technologies available for hybridization, Concentrating Solar Power (CSP) with parabolic trough is the most diffused because of its relatively conventional technology and ease of scale-up. CSP hybrids are well established worldwide, predominantly with natural gas: the hybridization options for CSP ranging from feed water heating, reheat steam, live steam to steam superheating. Based on a detailed thermodynamic cycle model of a reference small-size one pressure level Combined Cycle (CC) plant, the impact of CSP addition is thoroughly evaluated. Different hybrid schemes are evaluated and compared considering CC off-design operation. The goal of this study is to evaluate, from a thermodynamic point of view, three repowering options of a small-size CC with a CSP system in a hybrid system configuration and to quantify their potential benefits in terms of system's performance increase. In particular, the optimal size of CSP plant is shown for each investigated hybrid repowering options. The changes in CC steam cycle operating parameters are presented together with CC performance increase. It is shown that solar hybridization into an existing CC plant may give rise to a substantial benefit from a thermodynamic point of view.

International Journal of Energy Research

This paper proposes and analyses several configurations for hybridising concentrating solar power (CSP) plants with combined cycle gas turbines (CCGT). The objective is to increase the solar contribution to a large extent, much higher than those obtained in integrated solar combined cycles but maintaining synergies, which are usually lost when increasing the solar share. For that, two thermal energy management systems are introduced at different temperature levels. First, a configuration with only the low-temperature system is proposed. Then, an enhanced configuration with the low- and high-temperature systems is conceived. These configurations are compared to reference CSP and CCGT state-of-the-art plants. The analyses include different strategies of operation and two sizes for the thermal energy storage system. The results show that the first proposed configuration introduces some synergies but cannot improve the performance of the reference CSP and CCGT working separately, due to...

A dual-pressure air receiver cycle has previously been proposed to overcome limitations of combined cycle CSP plants. This work compares different configurations of the Stellenbosch University Direct Storage Charging Dual-Pressure Air Receiver (SUNDISC) cycle with each other and a single-pressure receiver reference cycle. A steady-state model of the SUNDISC cycle has been developed and simulation runs with it were conducted with different sizes of the major components, namely, low-pressure receiver system, steam turbine, solar field and thermal storage system. The configurations were evaluated mainly through two energetic performance indicators: the annual energy yield and the annual number of hours of no power generation. The latter is a good indication of the modeled plants’ ability to generate baseload electricity. The results of the simulations indicate superior performance of the SUNDISC cycle over the reference cycle as well as favorable plant configurations in terms of annual...

Applied Mechanics and Materials, 2014

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 .

Energies, 2023

In this study, the thermodynamic behavior of a combined cycle power plant with integrated solar-driven inlet air cooling was simulated for Tehran, Phoenix, and Houston during warm-hot seasons. A considerable reduction in the output power was realized during hot ambient conditions due to the lower density of the air and lower mass flow rate to the turbines. The output power decreases from 306.6 to 260.8 MW as ambient temperature increases from 15 to 45 • C. This research focuses on utilizing solar cooling systems to achieve low inlet air temperature to generate highelectricity yields. Four different types of solar collectors and two different absorption chiller units were selected and simulated for each city to achieve the required goal. It was identified that integrating a solar inlet air cooling (SIAC) system can avert the reduction in output power with no impact on efficiency. The humid climatic condition in Houston and the low electricity cost in Tehran posed some challenges in designing a feasible SIAC system. However, by optimizing the solar collectors and cooling capacities, an optimal solution for utilizing inlet air cooling in humid climates is presented. In terms of overall impact, the evacuated flat plate collector (EFPC) coupled with a double-effect absorption chiller displayed the best economic performance among the four variants under study. In Phoenix, this combination can maintain output power during hot days with a DPR of 2.96 years.