Preparation and Characterization of Andalusite Ceramic Used for Solar Thermal Power Generation

High-temperature thermal storage material is one of the critical materials of solar thermal power generation system. Andalusite, kaolin, talc, γ-Al2O3 and partially stabilized zireonia were used as the raw materials, and in-situ synthesis of cordierite was adopted to fabricate thermal storage material for solar thermal power generation via pressureless sintering. The phase compositions, microstructures and thermal shock resistances of the sintered samples were analyzed by XRD, SEM and EDS, and the corresponding mechanical properties were measured. The results show that the major phases of the samples are mullite and zirconium silicate, and the pores distribute uniformly. After being sintered at 1 460℃C, A4 sample exhibits a better mechanical performance and thermal shock resistance, its loss rate of bending strength after 30 cycles thermal shock is 3.04%, the bulk density and bending strength are 2.86 g.cm^-3 and 139.66 MPa, respectively. The better thermal shock resistance of the sample is closely related to the effect of zirconium silicate, such as its uniform distribution, nested growth with mullite, low thermal expansion coefficient, high thermal conductivity, etc. This ceramic can be widely used as one of potential thermal storage materials of solar thermal power generation system.

In-Situ Preparation and Thermal Shock Resistance of Mullite-Cordierite Heat Tube Material for Solar Thermal Power

In order to improve the thermal shock resistance of solar thermal heat transfer tube material, the mullite-cordierite composite ceramic as solar thermal heat transfer tube material were fabricated by pressureless sintering using a-Al203, Suzhou kaolin, talc, and feldspar as starting materials. The important parameter for solar thermal transfer tube such as water absorption （W）, bulk density （Db）, and the mechanical properties were investigated. The phase composition and microstructure of the composite ceramics were analyzed by XRD and SEM. The experimental results show that the B3 sintered at 1 300 ℃ and holding for 3 h has an optimum thermal shock resistance. The bending strength loss rate of B3 is only 2% at 1 100℃ by air quenching-strength test and the sample can endure 30 times thermal shock cycling, and the water absorption, the bulk density and the bending strength are 0.32%, 2.58 g·cm-3, and 125.59 MPa respectively. The XRD analysis indicated that the phase compositions of the sample were mullite, cordierite, corundum, and spinel. The SEM images illustrate that the cordierite is prismatic grain and the mullite is nano rod, showing a good thermal shock resistance for composite ceramics as potential solar thermal power material.

Proposal of a Solar Thermal Power Plant at Low Temperature Using Solar Thermal Collectors

To this day, only two types of solar power plants have been proposed and built: high temperature thermal solar one and photovoltaic one. It is here proposed a new type of solar thermal plant using glass-top flat surface solar collectors, so working at low temperature (i.e., below 100°C). This power plant is aimed at warm countries, i.e., the ones mainly located between -40° and 40° latitude, having available space along their coast. This land based plant, to install on the seashore, is technologically similar to the one used for OTEC (Ocean Thermal Energy Conversion). This plant, apart from supplying electricity with a much better thermodynamic efficiency than OTEC plants, has the main advantage of providing desalinated water for drinking and irrigation. This plant is designed to generate electricity (and desalinated water) night and day and all year round, by means of hot water storage, with just a variation of the power delivered depending on the season.

SMO Algorithm to Unravel CEED Problem using Wind and Solar

This research proposes a more advanced way to address Combined Economic Emission Dispatch(CEED)concerns.Economic Load Dispatch(ELD)and Economic Emission Dispatch(EED)have been implemented to reduce generating unit fuel costs and emissions.When both economics and emission tar-gets are taken into account,the dispatch of an aggregate cost-effective emission challenge emerges.This research affords a mathematical modeling-based analyti-cal technique for solving economic,emission,and collaborative economic and emission dispatch problems with only one goal.This study takes into account both the fuel cost target and the environmental impact of emissions.This bi-inten-tion CEED problem is converted to a solitary goal function using a price penalty factor technique.In this case,a metaheuristic and an environment-inspired,intel-ligent Spider Monkey Optimization technique(SMO)are used to address the CEED dilemma.By following the generator’s scheduling process,the SMO meth-od is used to regulate the output from the power generation system in terms of pollution and fuel cost.The Fission-Fusion social(FFS)structure of spider mon-keys promotes them to utilize a global optimization method known as SMO dur-ing foraging behaviour.The emphasis is mostly on lowering the cost of generation and pollution in order to improve the efficiency of the power system and han-dle dispatch problems with constraints.The economic dispatch has been reme-died,and the improved result demonstrates that the system’s performance is stable andflexible in real time.Finally,the system’s output demonstrates that the system has improved in resolving CEED difficulties.When compared to ear-lier investigations,the proposed model’sfindings have improved.As the gener-ating units,wind and solar are used to explore the CEED crisis in the IEEE 30 bus system.

Impacts of solar multiple on the performance of direct steam generation solar power tower plant with integrated thermal storage

Solar multiple （SM） and thermal storage capacity are two key design parameters for revealing the performance of direct steam generation （DSG） solar power tower plant. In the case of settled land area, SM and thermal storage capacity can be optimized to obtain the minimum levelized cost of electricity （LCOE） by adjusting the power generation output. Taking the dual-receiver DSG solar power tower plant with a given size of solar field equivalent electricity of 100 MWe in Sevilla as a reference case, the minimum LCOE is 21.77 /kWhe with an SM of 1.7 and a thermal storage capacity of 3 h. Besides Sevilla, two other sites are also introduced to discuss the influence of annual DNI. When compared with the case of Sevilla, the minimum LCOE and optimal SM of the San Jose site change just slightly, while the minimum LCOE of the Bishop site decreases by 32.8% and the optimal SM is reduced to 1.3. The influence of the size of solar field equivalent electricity is studied as well. The minimum LCOE decreases with the size of solar field, while the optimal SM and thermal storage capacity still remain unchanged. In addition, the sensitivity of different investment in sub-system is investigated. In terms ofoptimal SM and thermal storage capacity, they can decrease with the cost of thermal storage system but increase with the cost of power generation unit.

Research on solar aided coal-fired power generation system and performance analysis

Integrating solar power utilization systems with coal-fired power units, the solar aided coal-fired power generation (SACPG) shows a significant prospect for the large-scale utilization of solar energy and energy saving of thermal power units. The methods and mechanism of system integration were studied. The parabolic trough solar collectors were used to collect solar energy and the integration scheme of SACPG system was determined considering the matching of working fluid flows and energy flows. The thermodynamic characteristics of solar thermal power generation and their effects on the performance of thermal power units were studied, and based on this the integration and optimization model of system structure and parameters were built up. The integration rules and coupling mecha- nism of SACPG systems were summarized in accordance with simulation results. The economic analysis of this SACPG system showed that the solar LEC of a typical SACPG system, considering CO2 avoidance, is 0.098 $/kW·h, lower than that of SEGS, 0.14 $/kW·h.

Solar aided power generation:A review

Solar Aided Power Generation(SAPG)is the most efficient and economic ways to hybridise solar thermal energy and a fossil fuel fired regenerative Rankine cycle(RRC)power plant for power generation purpose.In such an SAPG plant,the solar thermal energy is used to displace the extraction steam by preheating the feedwater to the boiler.The displaced/saved extraction steam can,therefore,expand further in the steam turbine to generate power.The research and development of the SAPG technology started in the 1990s.This paper is trying to reviews and summarises the progress of research and development of the SAPG plant technology in last almost 30 or so years,including the technical and economic advantages of SAPG over other solar thermal power generation tech-nologies(e.g.solar alone power generation),various modelling techniques used to simulate SAPG perforamnce,impacts of SAPG plant’s configuration,size of solar field and strategies to adjust mass flow rate of extraction steam on the plant perforamnce,exergy analysis of SAPG plant and operation strategies to maximise plant’s economic returns etc.In addition,the directions for future R&D about SAPG technology have been pointed/proposed in this paper.

Operation Strategy Analysis and Configuration Optimization of Solar CCHP System

This paper proposed a new type of combined cooling heating and power(CCHP)system,including the parabolic trough solar thermal(PTST)power generation and gas turbine power generation.The thermal energy storage subsystem in the PTST unit provides both thermal energy and electrical energy.Based on the life cycle method,the configuration optimization under eight operation strategies is studied with the economy,energy,and environment indicators.The eight operation strategies include FEL,FEL-EC,FEL-TES,FEL-TES&EC,FTL,FTL-EC,FTL-TES,and FTL-TES&EC.The feasibility of each strategy is verified by taking a residential building cluster as an example.The indicators under the optimal configuration of each strategy are compared with that of the separate production(SP)system.The results showed that the PTST-CCHP system improves the environment and energy performance by changing the ratio of thermal energy and electric energy.The environment and energy indicators of FEL-TES&EC are superior to those of FTL-TES&EC in summer,and the results are just the opposite in winter.The initial annual investment of the PTST-CCHP system is higher than that of the SP system,but its economic performance is better than that of the SP system with the increase of life-cycle.

Analysis of heat flow diagram of small-scale power generation system:Innovative approaches for improving techno-economic and ecological indices

In this paper,the heat flow diagram of steam turbine model K-6-35 has been analyzed for innovative approaches towards improving the techno-economic and ecological indices of the small-scale power generation system.The numerical analysis is performed using IPSEpro process simulation software based on heat balance method under four different cases.It was found that the study of Solar Assisted Power Generation(SAPG)system has important practical significance in power generation with minimum pollutants and maximum efficiency.Both fuel-saving(FS)and power-boosting(PB)operation modes of the SAPG system are considered.Various types of stand-alone solar thermal power plants exhibited very low overall efficiency with many ecological advantages compared to the conventional thermal power plant based on fossil fuels.Besides,SAPG system with FS mode presented higher techno-economic indices and operation performance.An important reduction in fuel consumption and pollutant emissions could be obtained with SAPG system.Considering the hourly,daily,monthly,and yearly amount of saved fuel and reduced pollutants in the whole power plant,the SAPG system with FS mode can largely contribute to high ecological indices power generation.A thermal efficiency increased by 1.31%with specific equivalent fuel consumption decreased by 22.54 g/kWh was obtained with SAPG system.The coal consumption was reduced by 4.75%when SAPG system operates in FS mode.

Energy Analyses of Thermoelectric Renewable Energy Sources

The recent energy crisis and environmental burden are becoming increasingly urgent and drawing enormous attention to solar-energy utilization. Direct solar thermal power generation technologies, such as, thermoelectric, thermionic, magneto hydrodynamic, and alkali-metal thermoelectric methods, are among the most attractive ways to provide electric energy from solar heat. Direct solar thermal power generation has been an attractive electricity generation technology using a concentrator to gather solar radiation on a heat collector and then directly converting heat to electricity through a thermal electric conversion element. Compared with the traditional indirect solar thermal power technology utilizing a steam-turbine generator, the direct conversion technology can realize the thermal to electricity conversion without the conventional intermediate mechanical conversion process. The power system is, thus, easy to extend, stable to operate, reliable, and silent, making the method especially suitable for some small-scale distributed energy supply areas. Also, at some occasions that have high requirements on system stability, long service life, and noiselessness demand, such as military and deep-space exploration areas, direct solar thermal power generation has very attractive merit in practice. At present, the realistic conversion efficiency of direct solar thermal power technology is still not very high, mainly due to material restriction and inconvenient design. However, from the energy conversion aspect, there is no conventional intermediate mechanical conversion process in direct thermal power conversion, which therefore guarantees the enormous potential of thermal power efficiency when compared with traditional indirect solar thermal power technology [1].

Numerical Study on Heat Transfer and Frictional Resistance of Two Types of Molten Salts in Straight Channels and Supercritical Carbon Dioxide in Airfoil Channels

Molten salt and supercritical carbon dioxide(sCO_(2))are considered to be one of the most promising combined heat transfer refrigerants for third-generation solar thermal power generation.To evaluate the potential of chloride salts and carbonates in third-generation solar thermal power generation,this paper uses molten salts and sCO_(2)as the working media of printed circuit board heat exchangers(PCHE),and uses numerical simulation to study the heat transfer and friction of PCHE channels with different molten salts and sCO_(2),and establishes predictive correlations respectively.A local heat transfer and friction study was conducted on the sCO_(2)side of the airfoil channel,and it was found that the inlet mass flow rate has a significant impact on it,while the inlet temperature has a relatively small impact.A comprehensive comparison was made between the heat transfer and friction of two molten salts,and the comprehensive performance of chloride salts was 70%-80%higher than that of carbonates.The results indicate that the potential of chloride salts in third-generation solar thermal power generation is much greater than that of carbonates.

Structural Optimization of the Inlet Header of Supercritical Carbon Dioxide Printed Circuit Board Heat Exchanger

Supercritical carbon dioxide printed circuit board heat exchangers are expected to be applied in third-generation solar thermal power generation.However,the uniformity of supercritical carbon dioxide entering the heat exchanger has a significant impact on the overall performance of the heat exchanger.In order to improve the uniformity of flow distribution in the inlet header,this article studies and optimizes the inlet header of a printed circuit board heat exchanger through numerical simulation.The results indicate that when supercritical carbon dioxide flows through the header cavity,eddy currents will be generated,which will increase the uneven distribution of flow rate,while reducing the generation of eddy currents will improve the uniform distribution of flow rate.When the dimensionless factor of the inlet header is 6,the hyperbolic configuration is the optimal structure.We also reduced the eddy current region by adding transition segments,and the results showed that the structure was the best when the dilation angle was 10°,which reduced the non-uniformity by 21%compared to the hyperbolic configuration,providing guidance for engineering practice.

Performance of S-CO_2 Brayton Cycle and Organic Rankine Cycle(ORC) Combined System Considering the Diurnal Distribution of Solar Radiation

This paper researches the performance of a novel supercritical carbon dioxide(S-CO_2) Brayton cycle and organic Rankine cycle(ORC) combined system with a theoretical solar radiation diurnal distribution. The new system supplies all solar energy to a S-CO_2 Brayton cycle heater, where heat releasing from the S-CO_2 cooler is stored in the thermal storage system which is supplied to the ORC. Therefore, solar energy is kept at a high temperature, while at the same time the thermal storage system temperature is low. This paper builds a simple solar radiation diurnal distribution model. The maximum continuous working time, mass of thermal storage material, and parameter variations of the two cycles are simulated with the solar radiation diurnal distribution model. 10 organic fluids and 5 representative thermal storage materials are compared in this paper, with the mass and volume of these materials being shown. The longer the continuous working time is, the lower the system thermal efficiency is. The maximum continuous working time can reach 19.1 hours if the system provides a constant power output. At the same time, the system efficiency can be kept above 38% for most fluids.