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Industrial boilers are significant equipment in industrial operations used to provide steam or heat for production. More than 80% of fire-tube boilers use heavy oil in small and middle industries in Taiwan. Due to biodiesel as a sustainable fuel, the objective of this study is to measure experimentally and evaluated energy and exergy analysis of the fire-tube boiler using biodiesel (BD), undistilled biodiesel (UB), low sulfur oil (LSO), and ultra-low sulfur diesel (ULSD), and the various mixing ratios of undistilled biodiesel and low sulfur oil (UB90, UB70, and UB50) to reduce emissions from fire-tube boilers. Results from BD and UB are comparable, and UB exhibited a high NOx reduction rate of 68.9% and a high SO2 reduction rate of 99.5% compared to LSO. The boiler that employed UB decreased CO2 emissions, NOx, and SO2 emissions. NOx emission increases with increasing LSO content. The boiler’s maximum energy efficiency when using BD is 86.6%, and the overall exergy efficiency is 44.8%. The boiler with UB70 had the lowest energy efficiency of 73.5% and the lowest exergy efficiency of 38.7% because of the increased heat loss. The Benefits of this study are not only for boiler applications but also for government policy references.

The purpose of this study is to investigate the significant effect of ammonia-water dilution pressure and density on the thermodynamic performance of ammonia-water combined cycle through energy and exergy destruction, enthalpy temperature, yields, and flow velocity. The energyexergy analysis is conducted on the ammonia water combined cycle and the Rankine cycle, respectively. Engineering Equation Solver (EES) software is utilized for performing such detailed analyses. Values and ratios regarding heat drop and exergy loss is presented in separate tables for different equipment. The results obtained by the energy-exergy analysis indicate that net power increases with the increasing ammonia-water dilution pressure in the boiler. This trend continues until pressure range reach in [169.3 - 180] bar and after that, it starts to decrease. In addition, the increasing of ammonia-water dilution pressure leads to reduction of boiler both exergy and total exergy destructions, it also results in an increment in the exergy performance coefficient (EPC). Moreover, it is also noticed that the combined cycle system improves its efficiency by about 5.81% compared with gas turbines. [ABSTRACT FROM AUTHOR]

Abstract: The present work presents a thermodynamic performance analysis of a solar dryer with an evacuated-tube collector. Drying experiments for apples, carrots and apricots were conducted, after a preliminary stage of the investigation which included measurements for the determination of the collector efficiency. These results showed that the warm outlet air of the collector attains temperature levels suitable for drying of agricultural products without the need of preheating. Thus, the present collector was used as the heat source for a drying chamber in the frame of the development of a novel, convective, indirect solar dryer; given the fact that in the literature there are only a few studies about this type of collectors in conjunction with solar drying applications. Thin-layer drying models were fitted to the experimental drying curves, including the recent model of Diamante et al. which showed good correlation coefficients for all the tested products. Drying parameters such as moisture ratio and drying rates were calculated. Furthermore, an energetic/exergetic analysis of the dryer was also conducted and performance coefficients such as pick-up and exergy efficiencies, energy utilization ratio, exergy losses were determined for several configurations such as single and double-trays and several drying air velocities. On the other hand, an optimal collector surface area study was conducted, based on laws for minimum entropy generation. Design parameters such as optimum collector area were determined based on the minimum entropy generation number. The mass flow number, along with the maximum collector and fluid exit temperatures were studied in relation to the minimum entropy generation. The energy/exergy analysis proposed, provides a useful tool for the evaluation of this type of collectors regarding their effectiveness as part of a solar drying system. Moreover, the results of the present study showed that the proposed solar dryer has a capacity for drying larger quantities of the products than those considered (in the frame of the experimental study) given the high efficiency of the collector. In general, the proposed system provides an interesting option for the penetration of this type of collectors in large-scale applications in the agricultural and industrial sector. [Copyright &y& Elsevier]

• Energy-exergy analysis performed for a new integrated membrane desalination system. • The global water recovery factor is enhanced by membrane distillation. • Energy of hypersaline brine is harvested by reverse electrodialysis. • 16.6% reduction in specific energy consumption is obtained for the best scenario. Although desalination market is today dominated by Seawater Reverse Osmosis (SWRO), important technological issues remain unaddressed, specifically: relatively low water recovery factor (around 50%) and consequent huge amount of brine discharged, and energy consumption (3–5 kWh/m3) still far from the minimum thermodynamic value (∼1 kWh/m3). Herein, the energy performance of an innovative systems combining SWRO, Membrane Distillation (MD) and Reverse Electrodialysis (RED) for simultaneous production of water and energy is investigated. The valorization of hypersaline waste brine by Salinity Gradient Power production via RED and the achievement of high recovery factors (since MD is not limited by osmotic phenomena) represent a step forward to the practical implementation of Zero Liquid Discharge and low-energy desalination. The analysis is supported by lab-scale experimental tests carried out on MD and RED over a broad set of operational conditions. Among the different case studies investigated, exergetic efficiency reached 49% for the best scenario, i.e. MD feed temperature of 60 °C, MD brine concentration of 5 M NaCl, RED power density of 2.2 W/m2MP (MP: membrane pair). Compared to the benchmark flowsheet (only SWRO), up to 23% reduction in electrical energy consumption and 16.6% decrease in specific energy consumption were achieved when including a RED unit. The analysis also indicates that optimization of thermal energy input at the MD stage is critical, although it can potentially be fulfilled by low-grade waste heat or solar-thermal renewable sources. Overall, the proposed integrated system is coherent with the emergent paradigm of Circular Economy and the logic of Process Intensification. [ABSTRACT FROM AUTHOR]