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![Table 1 . Main parameter of the ORC system for turbofan engine [10]](profile/Syamimi-Saadon/publication/309593577/figure/tbl1/AS:668716102610947@1536445751052/Main-parameter-of-the-ORC-system-for-turbofan-engine-10_Q320.jpg)
Due to energy shortage and global warming, issues of energy saving have become more important. To increase the energy efficiency and reduce the fuel consumption, waste heat recovery is a significant method for energy saving. The organic Rankine cycle (ORC) has great potential to recover the waste heat from the core jet exhaust of a turbofan engine...
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... this analytical study, the distributed modelling is applied in order to simulate the two heat exchangers, which are the condenser and the evaporator. Figure 3 is showing three successive segments, noted i-1, i and i+1. As the precision is sufficient to suppose that heat capacity of the exhaust heat from jet engine and working fluid are roughly invariable in each discrete segment, to form the conservation equations, the single node modelling which is here, the NTU-ε method is applied. ...
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Due to global warming and high demand for energy, the use of heat recovery systems is increasing. Moreover, employing multi-generation systems has been taken into account more than before due to the increase in energy efficiency. In this study, a novel multi-generation system composed of organic Rankine cycle (ORC) and refrigeration cycle (REC) is...
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... Notably, as represented in the literature review above, the consciousness of reusing low and medium temperature heat sources has captivated many research around the globe and ORC seems to be the most promising option to reuse this waste heat. Our previous works [29,30] have attempted to explore this application. However, these works only considered an evaporator as the heat exchanger; therefore, the output power produced was quite inadequate. ...
... Thrust power is defined as T . F tot (29) Then, the waste exergy ratio is evaluated as [27,44,[49][50][51][52][53] Waste exergy ratio = (Total waste exergy output)/(Total exergy input) ...
This study addresses the performance analysis of a subcritical and supercritical Organic Rankine Cycle (ORC) with the addition of a preheater or superheater integrated with a turbofan engine. This analysis will try to explore the heat transfer throughout the evaporator for the purpose of determining the ORC output power and thermal efficiency. A simplified numerical model of the ORC for waste heat recovery is presented. The model depicts the evaporator by using a distributed model, and includes parameters such as the effectiveness, heat capacity and inlet temperature of the waste heat and the organic fluid. For a given set of initial parameter values, the output power and thermal efficiency, as well as the mass flow rate of the working fluid are acquired by solving the system’s thermodynamic cycle with the aid of MATLAB software. The model is then verified by using data from an industrial waste heat recovery system. The connection between the turbofan engine and the ORC system was established and evaluated by means of Thrust-Specific Fuel Consumption (TSFC) as well as fuel burn. It was found that the supercritical ORC with a preheater and superheater exhibits lower TSFC than the subcritical ORC, whereas the impact of the ORC in terms of waste heat recovery in relation to the environment and sustainability indices is quite small, but still considerable depending on the engine’s weight.
... There are a lot of discussions evolves around waste heat trying and proving that this recovery technology is a great resource of energy because of its huge amount wasted in our environment currently. The research on this low-grade heat recovery system also has been done by using organic fluid and the possibility of integrating with aircraft engine [6,7]. However, this system is not suitable for a smallscale gas turbine due to weight as well as the demand of water supply [8]. ...
Growing consumption of primary fossil fuels and massive discharge of pollutants are some of the results caused by the world’s growing population, and eventually the enlarging energy demand. It is therefore the main concerns that the developing world must face nowadays are the energy shortfall and the environmental destruction. And for these valid reasons the awareness of reusing the low-grade heat has captivated researchers in recent years. Due to its unique features, Stirling engines, is a powerful candidate to recover the waste heat by converting it into power. However, Stirling engine shows a drastic performance penalization if connected with lower temperature heat sources and therefore research has to be done to increase the performance of the heat transfer in the Stirling engine. Exhaustive research has been done by many investigators to enhance the heat transfer characteristics inside the tube heat exchangers. However, the areas related to outer tube geometries with different materials and different fins attachment have not yet been explored and this part is the important factor for an external combustion engine to enhance the heat transfer. Thus, the development of Stirling engine as waste heat recovery needs to focus on identification of heat transfer enhancement methods that can be applied at the outer part of tubular heater in order to achieve an optimum performance of the engine. Starting from a comprehensive review of Stirling engine, this paper presented a rigorous derivation of a novel waste heat recovery system using Stirling engine with large power that can benefit the environment and in line with national GTMP. Such result will be very useful in the preliminary design of a waste heat recovery system using Stirling engine and can be used in the estimation of power output for many applications.
... Worldwide energy consumption has increased by more than 40% over the last few decades and causes significant environmental problems and economic value. The misused energy from fuel derived from engine exhaust is more than 30-40% and only about 12-25% can be converted for useful work [3]. ...
Waste heat from industries such as steam power plants can be utilized to meet the world’s electricity need. However, it cannot be converted efficiently to electric power by using conventional power generation methods as opposed to a technology called Organic Rankine Cycle (ORC). ORC is one of the power plant systems that is a modification of the Rankine Cycle using organic working fluid. In this research, ORC was designed and manufactured using R-134a as working fluid and helical heat exchanger as evaporator and condenser. The design of ORC systems based on simulation using Cycle Tempo 5.0 with evaporator temperature of 90°C, condenser temperature of 10°C, inlet pressure of pump of 0.55 MPa, and inlet pressure of turbine of 0.79 MPa. The results of this study showed the length of tube evaporator and condenser of 10.61 m and 10.56 m, respectively, with system efficiency achieved at 3.8%. Based on experiment, with evaporator temperature of 95°C, condenser temperature of 10°C, inlet pressure of pump of 0.48 MPa and inlet pressure of turbine of 0.52 MPa so resulted of system efficiency of 3.33%.
... R245fa is chosen as it constantly shows the highest cycle thermal efficiency over extensive operating pressures. Recently, Saadon [7] and Saadon et al. [8] have done an analytical study on the integration of ORC system to aircraft turbofan engine. The objective of the study is to learn the characteristics of ORC system and its impact on turbofan engine. ...
Waste heat recovery is recognized as one of the methods to overcome this energy saving issue. In this paper, the Organic Rankine Cycle (ORC) system has been introduced for the waste heat recovery. The main objective of the study is to convert the unused heat into useful power, which could reduce the fuel consumption and also minimize the harmful exhaust transmission. A thermodynamic model of the waste heat recovery cycle is developed and validated. The eventual results depict a reasonable agreement for the ORC power output and its thermal performance, especially at higher turbine inlet pressure. Consequently, this ORC model is then connected to a turbofan engine. The performance analysis of the engine depicts that the lowest Thrust Specific Fuel Consumption (TSFC) is at 0.68 lbm/lbf.h with the thrust force of 7000 lbf, thus lower than the base cycle without ORC as waste heat recovery.
Global warming and climate change have been major problems in the present world. Greenhouse gas emissions contribute to global warming in which carbon dioxide being the best known. The aviation sector (excluding aerospace) has contributed to a total of 49.4 billion tons of carbon dioxide emission in 2016 alone. A solution to curb the increase of greenhouse gases has been proposed to temporarily solve this problem while future technological advancements occur. Having a heat recovery system by using heat exchangers in the engine helps to not only improves the performance of the engine but to also reduce temperature of the exhaust gases that will be eliminated as waste heat into the atmosphere. The main objective of the introduction of intercoolers and recuperators is to reduce the thrust specific fuel consumption whilst increasing the thrust and reducing emissions. This research thesis focuses on the analysis of intercooling and recuperation within the aspects of thermodynamics to be integrated into a typical turbofan engine. The analysis will be conducted via process simulation software – Aspen Plus V11 and the data from the software will be exported to Microsoft Excel for post-processing and graph visualization. Three main objectives of the study are to determine whether compression work will be reduced, studying the increase of thrust and performance of the engine with the positioning of heat exchangers and the improvement of TSFC with the integration of heat exchangers. For the first objective, it has been proven that there is a reduction in compression work for the recuperated engine of 7.64% but there is a 13.17% increase in compression work for the intercooled engine. For the second objective, thrust increased in both recuperated and intercooled cycles with 1.14% and 1.31% for the recuperated and intercooled cycles, respectively. Finally for the third objective, a decrease in TSFC for both recuperated and intercooled cycles show that both the heat recovery systems have an improvement of TSFC.
