Browsing by Author "Li, Chao"

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    Annual performance analysis and optimization of a solar tower aided coal-fired power plant
    (Elsevier, 2019-01-10) Li, Chao; Zhai, Rongrong; Yang, Yongping; Patchigolla, Kumar; Oakey, John E.; Turner, Peter J.
    The integration of solar energy into coal-fired power plants has been proven as a potential approach in the utilization of solar energy to reduce coal consumption. Moreover, solar augmentation offers low cost and low risk alternatives to stand-alone solar thermal power plants. In this study, the annual performance of a solar tower aided coal-fired power (STACP) system is investigated, and the influence of thermal storage system capacity on the annual solar generating power and annual solar-to-electricity efficiency is explored. The thermal storage system capacity is optimized to obtain the lowest levelized cost of electricity (LCOE). At the same time, the influence and sensitivity of several important economic factors are explored and assessed. Results demonstrate that compared to a coal-fired power system, the reduction in the annual average coal consumption rate of the STACP system with high direct normal irradiance (DNI), medium DNI, and low DNI are 5.79, 4.52, and 3.22 g/kWh, respectively. At a minimum, the annual coal consumption can be reduced by 14,000 t in a 600 MWe power generation unit. Because the same solar field is considered under different DNI conditions, the LCOE in the high DNI, medium DNI, and low DNI scenarios are all fairly similar (6.37, 6.40, and 6.41 ¢/kWh, respectively). When the solar multiple is 3.0, the optimal thermal storage capacity of the STACP system, with high, medium, and low DNIs are 6.73, 4.42, and 2.21 h, respectively. The sensitivity analysis shows that the change in economic parameters exerts more influence on the STACP system with the high DNI compared with the other two scenarios.
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    A customised lean model for a Chinese aerospace OEM (Original Equipment Manufacturer)
    (Cranfield University, 2011-04) Li, Chao; Baguley, Paul; Tiwari, Ashutosh
    The aim of this research is to introduce Lean Thinking in a systematic and cost effective way; moreover, it is to bring Lean Principles and apply Lean Tools to the new aerospace companies. In particular the research will develop a customised Lean manufacturing model. The following objectives will be achieved during the research. 1); Investigate the principal features of Lean Thinking, and identify state of the art in Lean manufacturing implementation. 2); Identify the current situation of a specific Chinese aerospace company and the requirements needed in becoming Lean. 3); Develop a customised Lean model for applying Lean into a new Chinese aerospace company. 4); Validate the Lean manufacturing model by experts in the company and university. The Chinese traditional thinking is different from lean think. Therefore, to implement Lean in China will face some distinct barriers. The author attempts to resolve these problems through a customised lean model. According to the literature review and researcher‘s knowledge, there is no paper developing a model linking to the barriers of lean implementation in Chinese manufacturing. Therefore, the author will attempt to fill in this gap during the research. The questionnaire and assessment tool will be used to collect information from the company. Best practices will help to establish the structure of the model. However, in China, most companies implement lean through copying examples from the United States, UK and other Western countries without combining their current situation and culture. The contribution of this research is to develop a model to link Chinese barriers and a company‘s situation for lean implementation. Finally, this model will be validated by company and academic experts. The first validation is based on the sponsoring company. Other validations are achieved by academic experts and industrial expert.
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    Off-design thermodynamic performances of a solar tower aided coal-fired power plant for different solar multiples with thermal energy storage
    (Elsevier, 2018-08-25) Li, Chao; Yang, Zhiping; Zhai, Rongrong; Yang, Yongping; Patchigolla, Kumar; Oakey, John E.
    Solar aided coal-fired power system has been proven to be a promising way to utilise solar energy in large scale. In this paper, the performances of the solar tower aided coal-fired power (STACP) system at 100% load, 75% load, and 50% load for different days are investigated and the maximum solar power that the boiler can absorb under different plant loads are explored. Then, the effects of solar multiple (SM) and the thermal energy storage (TES) hour on the daily performance of STACP system are investigated. Results show that the maximum solar power that a 600 MWe boiler can absorb at 100% load, 75% load and 50% load are 76.4 MWth, 54.2 MWth and 23.0 MWth, respectively. Due to the augmented energy from the solar field, the maximum standard coal consumption rate is reduced by 13.53 g/kWh, 12.81 g/kWh and 8.22 g/kWh at 100% load, 75% load and 50% load, respectively. With an increase of solar power input, the boiler efficiency, overall system efficiency and solar thermal-to-electricity efficiency show a downward trend. In addition, the daily coal consumption of summer solstice is the lowest while the winter solstice is the highest for a particular SM and TES hour.
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    Thermal performance of different integration schemes for a solar tower aided coal-fired power system
    (Elsevier, 2018-06-23) Li, Chao; Zhai, Rongrong; Yang, Yongping; Patchigolla, Kumar; Oakey, John E.
    A Solar Tower Aided Coal-fired Power (STACP) system utilizes a solar tower coupled to a conventional coal-fired power system to reduce pollutants, greenhouse gas emissions and the investment of solar energy facilities. This paper examines three different schemes for integrating solar energy into a conventional boiler. For each scheme, an energy and exergy analysis of a 600 MWe supercritical coal-fired power system is combined with 53 MWth of solar energy in both a fuel saving mode and a power boosting mode. The results show that, for all these integration schemes, the boiler’s efficiency and system’s efficiency are reduced. However, the standard coal consumption rate is lower in comparison to conventional power plants and the standard coal consumption rate in the fuel saving mode is lower than that in the power boosting mode for all three schemes. Comprehensively considering both the standard coal consumption rate and efficiency, the scheme that uses solar energy to heat superheat steam and subcooled feed-water is the best integration option. Compared with a coal-fired only system, the saved standard coal consumption rate of the above mentioned scheme in fuel saving mode and power boosting mode can reach up to 11.15 g/kWh and 11.11 g/kWh, respectively. Exergy analysis shows, for STACP system, exergy losses of boiler and solar field contribute over 88% of whole system’s exergy loss.