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    Performance Assessment of a Novel Solar and Biomass-Based Multi-Generation System Equipped with Nanofluid-Based Compound Parabolic Collectors
    (Mdpi, 2022) Ibrahim, Alla Ali; Kayfeci, Muhammet; Georgiev, Aleksandar G.; Dolgun, Guelsah Karaca; Kecebas, Ali
    The current paper proposes a novel multi-generation system, integrated with compound parabolic collectors and a biomass combustor. In addition to analyzing the comprehensive system in a steady state, the feasibility of using nanofluids as heat transfer fluids in the solar cycle and their effect on the overall performance of the system was studied. The multi-generation system is generally designed for generating electricity, cooling, freshwater, drying, hot water, and hydrogen, with the help of six subsystems. These include a double stage refrigeration system, an organic Rankine cycle, a steam Rankine cycle, a dryer, a proton exchange membrane electrolyzer, and a multistage flash distillation system. Two types of nanoparticles (graphene, silver), which have various high-quality properties when used within ethylene glycol, were chosen as absorbing fluids in the solar cycle. The performance parameters of the base case thermodynamic analysis and some of the variable parameters were calculated, and their effect on system performance was determined. According to the results, a spike in solar irradiation, ambient temperature, output temperature of biomass combustor and nanofluids' concentration positively affected the overall system performance. The results also clearly showed an improvement in system performance when using nanofluids as working fluids in solar collectors.
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    THERMO-ENVIRONMENTAL ANALYSIS OF A NOVEL SOLAR AND BIOMASS-BASED MULTI-GENERATION SYSTEM EQUIPPED WITH NANOFLUID-BASED COMPOUND PARABOLIC COLLECTORS
    (2021-11) Ibrahim, Alla Ali
    In recent decades, the supply of various types of energy has become the predominant application of distributed generation systems. The depletion of fossil fuels, rising electricity prices, climate change and a significant increase in energy demand are the main reasons for this trend. Solar, geothermal, wind and biomass energy technologies are among the emerging sciences due to their availability, low cost, and environmental impact during operation. The current thesis proposes a novel multi-generation system, which is integrated with compound parabolic collectors and a biomass combustor. Besides thermodynamic and environmental analyzing the comprehensive system in a steady state, the feasibility of using nanofluids as an absorption fluid in the solar cycle and its effect on the overall performance of the mentioned system was studied. The multi-generation system is generally designed for generating electricity, cooling/heating, freshwater, drying, hot water, and hydrogen with the help of six subsystems, including a double stage refrigeration system, an organic Rankine cycle, a steam Rankine cycle, a dryer, a proton exchange membrane electrolyzer, and a multistage flash distillation system. Two types of nanoparticles (Graphene, Silver), which have various high-quality properties when used within the ethylene glycol, were chosen as heat transfer fluids in the solar cycle. The performance parameters of the base case thermodynamic analysis and some of the variable parameters were calculated and their effect on system performance was determined. According to the results, the system performance actually improved when nanofluids were used as working fluids in the solar collector. It was found that the graphene nanoparticles were the most effective. The overall energy/exergy efficiencies were recorded for the multi-generation system, respectively, 34.72% and 20.73% when a base fluid was used. The overall efficiencies increased to 35.6% and 21.15% when graphene-ethylene glycol nanofluid was used. The highest exergy destruction rates of 15.42 MW and 9.14 MW were obtained for the steam and organic Rankine cycle subsystems, respectively. The freshwater production by the desalination subsystem was 37.93 kg/s and hydrogen production by PEM electrolyzer was 44.77 kg/h. The environmental impact assessment gave a strong impetus to switch to multi-generational systems as CO2 emissions decreased from 1123 kg/MWh using the single-generation system to 364 kg/MWh using the multi-generation system. According to the analyses, spike in solar irradiation, ambient temperature, output temperature of biomass combustor, nanofluids’ concentration, ORC working fluid, air-biomass flow rate, and inlet pressure of both Rankine cycles turbines positively affected the overall system performance.