Advanced exergy analysis for a bottoming organic rankine cycle coupled to an internal combustion engine

Abstract

This paper deals with the evaluation and analysis of a bottoming ORC cycle coupled to an IC engine by means of conventional and advanced exergy analysis. Using experimental data of an ORC coupled to a 2 l turbocharged engine, both conventional and advanced exergy analysis are carried out. Splitting the exergy in the advanced exergy analysis into unavoidable and avoidable provides a measure of the potential of improving the efficiency of this component. On the other hand, splitting the exergy into endogenous and exogenous provides information between interactions among system components. The result of this study shows that there is a high potential of improvement in this type of cycles. Although, from the conventional analysis, the exergy destruction rate of boiler is greater than the one of the expander, condenser and pump, the advanced exergy analysis suggests that the first priority of improvement should be given to the expander, followed by the pump, the condenser and the boiler. A total amount of 3.75 kW (36.5%) of exergy destruction rate could be lowered, taking account that only the avoidable part of the exergy destruction rate can be reduced.

Advance Exergo-Economic Analysis of a Waste Heat Recovery System Using ORC for a Bottoming Natural Gas Engine

“…Also, several works have combined these studies to obtain improvement potentials. In applications in turbocharged combustion engines, conventional exergetic analysis gives the evaporator and the expander priority improvement potential while advanced exergy analysis suggests the expander and pump as a priority, and the cycle exergy destruction can be reduced by 36.5% [25]. For applications of advanced exergo-economic analysis taking into account waste heat recovery in geothermal applications, low-temperature solar applications, and waste heat recovery from engine gases, the exergetic efficiency of the ORC improves by 20%, optimizing the system through advanced exergetic analysis and proposing the expander, evaporator, condenser, and pump as improvement potentials.…”

Thermoeconomic Modelling and Parametric Study of a Simple ORC for the Recovery of Waste Heat in a 2 MW Gas Engine under Different Working Fluids

“…However, the variation in pump efficiency in the same study range does not significantly affect the ∆BSFC, yielding values of 0.041% for toluene, 0.0043% for acetone, and 0.049% for cyclohexane, according to Figure 3d. On the other hand, in terms of exergetic analysis, the results show that the increase in turbine efficiency in the range of study generates an increase in exergetic efficiency of 47.4% (toluene), 16.01% (acetone), and 14.1% (cyclohexane), as shown in Figure 3c. However, the variation in pump efficiency did not significantly affect the exergetic efficiency, whose behavior was similar when studying the ∆BSFC and the Wcomb.…”

“…Numerous studies have been carried out on the application of ORC systems in ICE, which has covered working fluid selection methodologies [12][13][14], exergy and energy analysis [15,16], thermo-economic optimization [17], and comparative analysis of different ORC configurations performance [18]. Regarding the studies on the performance of organic fluids in ORC coupled to ICE, there are those developed by Scaccabarozzi et al [19], who performed tests with 22 working fluids, such as pure fluids, synthetic refrigerants, and binary mixtures, determining that the use of binary mixtures does not lead to a considerable increase in thermal efficiency compared to pure fluids.…”

Exergoeconomic analysis and optimization of reverse osmosis desalination integrated with geothermal energy

“…Their results show that although exergy analysis shows that exergy and boiler destruction rates are greater than expander, condenser, and pump, but advanced exergy analysis shows that expander, pump, condenser, and finally boiler are at the priority to improve equipment. 16 Sohani et al developed a model to determine the air properties of a product of indirect dew point cooler with cross-flow heat exchanger and optimized it with neural network methods. 17,18 They also investigated direct and indirect two-stage evaporative coolers and evaluated the impact of changes in parameters affecting different system performance criteria, including the output air conditions of each stage, cooling capacity, resource consumption and their ratio, and operating and initial costs.…”