Conceptual design of novel He-SCO2 Brayton cycles for ultra-high-temperature concentrating solar power

Li, Qing; E, Erqi; Qiu, Yu; Wang, Jikang; Zhang, Yuan-Ting

doi:10.1016/j.enconman.2022.115618

Cited by 20 publications

(3 citation statements)

References 41 publications

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“…These two performance advantages become more significant as the maximum cycle temperature increases [25]. Moreover, the SCO 2 cycle's heater can achieve a temperature difference exceeding 200 • C between its two terminals [26], making it highly compatible with the heat storage unit [27]. Furthermore, employing the SCO 2 cycle in an SPT grants several advantages over the steam Rankine cycle, including greater adaptability to off-design operating conditions [28], applicability to arid areas using dry-cooling methods [29], and a smaller heat exchanger and turbomachinery [30].…”

Section: Introductionmentioning

confidence: 99%

Triple-Objective Optimization of SCO2 Brayton Cycles for Next-Generation Solar Power Tower

Qiu

2023

Energies

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In this paper, the SCO2 Brayton regenerative and recompression cycles are studied and optimized for a next-generation solar power tower under a maximum cycle temperature of over 700 °C. First, a steady-state thermodynamic model is developed and validated, and the impacts of different operating parameters on three critical performance indexes, including the cycle thermal efficiency, specific work, and heat storage temperature difference, are analyzed. The results reveal that these performance indexes are influenced by the operating pressures, the SCO2 split ratio, and the effectiveness of the regenerators in complex ways. Subsequently, considering the three performance indexes as the optimization objectives, a triple-objective optimization is carried out to determine the optimal operating variables with the aim of obtaining Pareto solutions for both cycles. The optimization indicates that the regenerative cycle can achieve the maximum heat storage temperature difference and the maximum specific work of 396.4 °C and 180.6 kW·kg−1, respectively, while the recompression cycle can reach the maximum thermal efficiency of 55.95%. Moreover, the optimized maximum and minimum pressure values of both cycles are found to be around 30 MPa and 8.2 MPa, respectively. Additionally, the distributions of the optimized values of the regenerator effectiveness and the SCO2 split ratio show different influences on the performance of the cycles. Therefore, different cycles with different optimized variables should be considered to achieve specific cycle performance. When considering thermal efficiency as the most important performance index, the recompression cycle should be adopted. Meanwhile, its SCO2 split ratio and the regenerator effectiveness should be close to 0.7 and 0.95, respectively. When considering heat storage temperature difference or specific work as the most important performance index, the regenerative cycle should be adopted. Meanwhile, its regenerator effectiveness should be close to 0.75. The results from this study will be helpful for the optimization of superior SCO2 cycles for next-generation solar tower plants.

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Section: Introductionmentioning

confidence: 99%

Triple-Objective Optimization of SCO2 Brayton Cycles for Next-Generation Solar Power Tower

Qiu

2023

Energies

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“…4 To improve the power cycle efficiency, the temperature of the solarthermal conversion has been increased continuously during the last two decades. 55 Recently, a solar power tower system with graphite-based receiver has even been proposed to operate at above 1300 C. 5,54 However, the radiative thermal loss from the solar absorber increases with the fourth power of temperature, reducing the photothermal efficiency of the absorber signicantly. 56,57 To ensure that the solar-electric efficiency, which is the product of the photothermal efficiency and the power cycle efficiency, can be improved effectively under high temperature, the photothermal efficiency is necessary to be as high as possible.…”

Section: Introductionmentioning

confidence: 99%

Near-perfect spectrally-selective metasurface solar absorber based on tungsten octagonal prism array

Guo

Zhang

et al. 2022

RSC Adv.

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Low‐Cost and Large‐Scale Producible Biomimetic Radiative Cooling Glass with Multiband Radiative Regulation Performance

Zhang

Li²,

Wang

et al. 2022

Advanced Optical Materials

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As human civilization progressed and economic growth accelerated, researchers focused on creating comfortable living conditions to satisfy the growing requirements for cooling. [1][2][3][4] Active cooling apparatuses, such as air conditioners, have been broadly employed for the heat management of envelopments, such as buildings and vehicles. However, they deplete a considerable amount of energy. [5][6][7][8] Approximately 44% of the total energy expenditure in buildings can be attributed to heating, cooling, ventilation, and lighting systems in recently constructed buildings. [9] Air conditioners are responsible for the decrease in the driving range of electric vehicles of up to 53.7%. [10,11] It has become a long-term goal for advanced proactive temperature-managed envelopments to maintain an optimal interior air temperature with the least energy expenditure.Solar irradiation is a significant factor influencing energy depletion in the refrigeration systems of vehicles and buildings, accounting for almost 40%-70% of the entire cooling power burden in vehicles and buildings. [12,13] Generally, the solar irradiance power density under AM1.5 can reach 1000 W m −2 , with visible, infrared, and UV percentages of 50%, 43%, and 7%, respectively. [14] To eliminate the negative effects of solar radiation on the cooling energy load of buildings, zero-energy passive radiative cooling is a practical energy conservation tactic. [15][16][17][18][19] Excessive building temperatures in hot weather can be decreased by reflecting the entire solar irradiation while radiating heat to frigid cosmic space. [19][20][21][22][23][24] In the past few years, extensive efforts have been made to promote daytime radiative cooling technology. Numerous materials and structures have been proposed to improve the cooling performance using multilayer films, [25,26] photonic crystals, [27] dielectric particle mixtures, [28][29][30][31][32] micro/nanoporous structures, [33][34][35] and biomimetic wrinkle structures. [36,37] Nevertheless, most daytime radiative cooling technologies do not consider lighting and esthetic purposes and cannot be applied to objects such as the windows and glass curtain walls of buildings and vehicles. [38][39][40][41][42] Conventional windows (particularly skylights) in vehicles and buildings transmit almost 90% of the total incident solar radiation [43][44][45] Common glass without spectral regulation effect cannot offer an energy-saving function, and radiative cooling technology without visible transparency cannot satisfy the illumination and esthetic demands. Herein, the concept of utilizing a biomimetic beetle cuticle structure, guided by principles of Chinese Taoist philosophy, is proposed to accomplish efficient radiative regulation. Subsequently, low-cost biomimetic radiative cooling (Bio-RC) glass is presented, which can reduce the temperature of buildings throughout daytime by blocking near-infrared (NIR) radiation, conveying visible light, and emitting heat within the atmospheric window. Utilizing only three laye...

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Conceptual design of novel He-SCO2 Brayton cycles for ultra-high-temperature concentrating solar power

Cited by 20 publications

References 41 publications

Triple-Objective Optimization of SCO2 Brayton Cycles for Next-Generation Solar Power Tower

Triple-Objective Optimization of SCO2 Brayton Cycles for Next-Generation Solar Power Tower

Near-perfect spectrally-selective metasurface solar absorber based on tungsten octagonal prism array

Low‐Cost and Large‐Scale Producible Biomimetic Radiative Cooling Glass with Multiband Radiative Regulation Performance

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