Proposal and assessment of a novel supercritical CO2 Brayton cycle integrated with LiBr absorption chiller for concentrated solar power applications

Ma, Yan; Zhang, Xuwei; Liu, Ming; Yan, Junjie; Liu, Jiping

doi:10.1016/j.energy.2018.01.155

Cited by 98 publications

(15 citation statements)

References 42 publications

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“…4,5 Numerous cycle designs of S-CO 2 cycle were proposed and evaluated for applications in different power generation scenarios, such as nuclear power plant, 6 coal-fired plant, 7 waste heat recovery 8 and CSP plant. 9 Many previous works were carried out on the parametric studies of the S-CO 2 cycle with an emphasis on the CSP application. Among different cycle designs, the recompression with an intercooled main compressor (ICMC) was considered as an competitive option due to the outstanding cycle performance and large temperature differential in the cycle hot end for the integration of the thermal storage system.…”

Section: Introductionmentioning

confidence: 99%

Investigation of off‐design characteristics of an improved recompression supercritical carbon dioxide cycle for concentrated solar power application

Morosuk

Liu

et al. 2020

Int J Energy Res

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Summary The off‐design characteristics of an improved recompression supercritical carbon dioxide cycle integrated with a two‐stage intercooled main compressor are investigated with a focus on the concentrated solar power application. An off‐design model is established for each crucial component of the cycle system of 100‐megawatt scale. Four cycle control schemes with different main compressor configurations or/and cycle maximum pressure modes are evaluated and compared. A sensitivity analysis is performed on the parameters related to the cycle thermal input and ambient condition to predict the off‐design characteristics due to the plant dispatch and ambient condition change in a solar power plant. The off‐design results regarding the cycle thermodynamic performance and operational issue prevention are presented. The effect of the design‐point value of the main compressor inlet temperature on the off‐design characteristics is evaluated with the comparison among the results at three design points. The results reveal that the compressor surge may occur to the main compressor with basic configuration as the main compressor inlet temperature decreases to a certain value beneath the corresponding design point. By contrast, the surge risk can be prevented with the modified main compressor configuration by activating the recirculation system and the cycle can thus operate normally in the entire off‐design range of main compressor inlet temperature. The off‐design change in thermal input has overall limited effects on the cycle system control. No operational compressor issues occur for the main compressor with either basic or modified configuration as the thermal input deviates from the design points and varies in the studied ranges. The cycle maximum pressure mode has slight effects on the cycle thermodynamic performance as the thermal input deviates from the design point. The flexible cycle maximum pressure mode has slightly lower sensitivity to the thermal input variation in net output power due to the counteraction of mass flowrate variation. The selection of the design‐point value of the main compressor inlet temperature has significant effects on the off‐design characteristics of the cycle. A low design‐point value of the main compressor inlet temperature leads to less demanding control action for operational issue prevention whereas a high design‐point main compressor inlet temperature results in overall more stable thermodynamic performance under off‐design conditions. Among other schemes, the fixed maximum pressure mode with the modified main compressor configuration is found to be the most satisfactory one due to the consequent superior efficiency, steady net output power, and free of hazardous operating issues despite the relatively demanding task of compressor surge prevention. The developed control scheme can be further improved by implementing parametric optimization during the off‐design operation.

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Section: Introductionmentioning

confidence: 99%

Investigation of off‐design characteristics of an improved recompression supercritical carbon dioxide cycle for concentrated solar power application

Morosuk

Liu

et al. 2020

Int J Energy Res

Self Cite

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“…Zeyghami and Khalili proposed a daytime radiative cooling concept to improve system performance [5]. Ma et al suggested an S-CO 2 Brayton cycle integrated with LiBr absorption chiller to minimize exergy losses [6].…”

Section: Introductionmentioning

confidence: 99%

Direction for High-Performance Supercritical CO2 Centrifugal Compressor Design for Dry Cooled Supercritical CO2 Brayton Cycle

et al. 2019

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To overcome the degradation of the cycle efficiency of a supercritical carbon dioxide (S-CO2) Brayton cycle with dry cooling, this study proposes an improved design of an S-CO2 centrifugal compressor. The conventional air centrifugal compressor can achieve higher efficiency as backsweep angle increases. However, the structural issue restricts the maximum allowable angle (−50~−56°). In this study, an S-CO2 centrifugal compressor performance was examined while changing the backward sweep angle at impeller exit to study if the previous optimum backsweep angle for an air centrifugal compressor is still valid when the fluid has changed. It is shown through an analysis that an S-CO2 centrifugal compressor can achieve the highest efficiency at −70° backsweep angle, which is greater than the typical design value. The S-CO2 centrifugal compressor is less restricted from a structural integrity issue because it has low relative Mach number regardless of the low sound speed near critical point (Tc = 304.11 K, Pc = 7377 kPa). It is also shown in the paper that the variation of compressibility factor does not impact on its total to total efficiency since its Mach number is still lower than unity. Finally, it is also shown that a backward sweep impeller can achieve higher pressure ratio and operate stably in wider range as the mass flow rate is decreased. As further works, the suggested concept will be validated by the structural analysis and the compressor performance test.

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“…Fan assisted finned tube air cooler was used as the heat rejection component and the control strategies of the experimental rig were demonstrated. Ma et al [176] proposed an economic assessment of a novel dry cooled sCO2 power cycle (RBC combined with absorption chiller) integrated with molten salt solar power tower and reported an efficiency improvement of 5.19% over the RBC cycle. The influence of pressure drop in the heat exchanger and air temperature fluctuation on the cycle performance was also investigated.…”

Section: Research Studies With Sco2 Power Cycles Using Dry Coolingmentioning

confidence: 99%

Investigating the effect of dry cooling system design on the performance of supercritical CO2 cycle in concentrated solar power application

Ehsan¹

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Owing to water deficit and environmental concerns, the compatibility of dry cooling technology with supercritical CO2 (sCO2) power cycle in concentrated solar power (CSP) offers superior thermal performance even at higher climate temperatures. One of the key challenges associated with sCO2 power cycles is the cooling of working fluid near the critical temperature and pressure. The nonlinear and sharp variation of sCO2 properties with bulk temperature poses a unique heat exchanger design problem not encountered with the constant property fluids. A reliable and well-designed cooling system is required for the efficient and smooth operation of a thermal power plant. In arid areas, natural draft dry cooling towers (NDDCT) are preferred over the wet coolers due to the insufficient water supply, environmental concern and the high maintenance and operation cost related to wet cooling.

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Proposal and assessment of a novel supercritical CO2 Brayton cycle integrated with LiBr absorption chiller for concentrated solar power applications

Cited by 98 publications

References 42 publications

Investigation of off‐design characteristics of an improved recompression supercritical carbon dioxide cycle for concentrated solar power application

Investigation of off‐design characteristics of an improved recompression supercritical carbon dioxide cycle for concentrated solar power application

Direction for High-Performance Supercritical CO2 Centrifugal Compressor Design for Dry Cooled Supercritical CO2 Brayton Cycle

Investigating the effect of dry cooling system design on the performance of supercritical CO2 cycle in concentrated solar power application

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Proposal and assessment of a novel supercritical CO2 Brayton cycle integrated with LiBr absorption chiller for concentrated solar power applications

Cited by 98 publications

References 42 publications

Investigation of off‐design characteristics of an improved recompression supercritical carbon dioxide cycle for concentrated solar power application

Investigation of off‐design characteristics of an improved recompression supercritical carbon dioxide cycle for concentrated solar power application

Direction for High-Performance Supercritical CO2 Centrifugal Compressor Design for Dry Cooled Supercritical CO2 Brayton Cycle

Investigating the effect of dry cooling system design on the performance of supercritical CO2&nbsp;cycle in concentrated solar power application

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Investigating the effect of dry cooling system design on the performance of supercritical CO2 cycle in concentrated solar power application