Integrated design of working fluid and organic Rankine cycle utilizing transient exhaust gases of heavy-duty vehicles

2019 ◽  
Vol 255 ◽  
pp. 113207 ◽  
Author(s):  
Johannes Schilling ◽  
Katharina Eichler ◽  
Benedikt Kölsch ◽  
Stefan Pischinger ◽  
André Bardow
2021 ◽  
pp. 1-21
Author(s):  
G.E. Pateropoulos ◽  
T.G. Efstathiadis ◽  
A.I. Kalfas

ABSTRACT The potential to recover waste heat from the exhaust gases of a turboprop engine and produce useful work through an Organic Rankine Cycle (ORC) is investigated. A thermodynamic analysis of the engine’s Brayton cycle is derived to determine the heat source available for exploitation. The aim is to use the aircraft engine fuel as the working fluid of the organic Rankine cycle in order to reduce the extra weight of the waste heat recovery system and keep the thrust-to-weight ratio as high as possible. A surrogate fuel with thermophysical properties similar to aviation gas turbine fuel is used for the ORC simulation. The evaporator design as well as the weight minimisation and safety of the suggested application are the most crucial aspects determining the feasibility of the proposed concept. The results show that there is potential in the exhaust gases to produce up to 50kW of power, corresponding to a 10.1% improvement of the overall thermal efficiency of the engine.


Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1317 ◽  
Author(s):  
Guillermo Valencia Ochoa ◽  
Cesar Isaza-Roldan ◽  
Jorge Duarte Forero

The waste heat recovery system (WHRS) is a good alternative to provide a solution to the waste energy emanated in the exhaust gases of the internal combustion engine (ICE). Therefore, it is useful to carry out research to improve the thermal efficiency of the ICE through a WHRS based on the organic Rankine cycle (ORC), since this type of system takes advantage of the heat of the exhaust gases to generate electrical energy. The organic working fluid selection was developed according to environmental criteria, operational parameters, thermodynamic conditions of the gas engine, and investment costs. An economic analysis is presented for the systems operating with three selected working fluids: toluene, acetone, and heptane, considering the main costs involved in the design and operation of the thermal system. Furthermore, an exergo-advanced study is presented on the WHRS based on ORC integrated to the ICE, which is a Jenbacher JMS 612 GS-N of 2 MW power fueled with natural gas. This advanced exergetic analysis allowed us to know the opportunities for improvement of the equipment and the increase in the thermodynamic performance of the ICE. The results show that when using acetone as the organic working fluid, there is a greater tendency of improvement of endogenous character in Pump 2 of around 80%. When using heptane it was manifested that for the turbine there are near to 77% opportunities for improvement, and the use of toluene in the turbine gave a rate of improvement of 70%. Finally, some case studies are presented to study the effect of condensation temperature, the pinch point temperature in the evaporator, and the pressure ratio on the direct, indirect, and fixed investment costs, where the higher investment costs were presented with the acetone, and lower costs when using the toluene as working fluid.


2016 ◽  
Author(s):  
Roberto Cipollone ◽  
Davide Di Battista ◽  
Andrea Perosino ◽  
Federica Bettoja

Author(s):  
Wolfgang Lang ◽  
Piero Colonna ◽  
Raimund Almbauer

This paper documents a feasibility study on a waste heat recovery system for heavy-duty truck engines based on an organic Rankine cycle (ORC) turbogenerator. The study addresses many of the challenges of a mobile automotive application: The system must be simple, efficient, relatively small, lightweight, and the working fluid must satisfy the many technical, environmental, and toxicological requirements typical of the automotive sector. The choice of a siloxane as the working fluid allows for the preliminary design of an efficient radial turbine, whose shaft can be lubricated by the working fluid itself. The system's heat exchangers, though more voluminous than desirable, are within acceptable limits. The simulated ORC system would add approximately 9.6 kW at the design point, corresponding to a truck engine power output of 150 kW at 1500 rpm. Future work will be devoted to further system and components optimization by means of simulations, to the study of dynamic operation and control, and will be followed by the design and construction of a laboratory test bench for mini-ORC systems and components.


Author(s):  
Matthias Lampe ◽  
Carlo De Servi ◽  
Johannes Schilling ◽  
André Bardow ◽  
Piero Colonna

Abstract The conventional design of organic Rankine cycle (ORC) power systems starts with the selection of the working fluid and the subsequent optimization of the corresponding thermodynamic cycle. More recently, systematic methods have been proposed integrating the selection of the working fluid into the optimization of the thermodynamic cycle. However, in both cases, the turbine is designed subsequently. This procedure can lead to a suboptimal design, especially in the case of mini- and small-scale ORC systems, since the preselected combination of working fluid and operating conditions may lead to infeasible turbine designs. The resulting iterative design procedure may end in conservative solutions after multiple trial-and-error attempts due to the strong interdependence of the many design variables and constraints involved. In this work, we therefore present a new design and optimization method integrating working fluid selection, thermodynamic cycle design, and preliminary turbine design. To this purpose, our recent 1-stage continuous-molecular targeting (CoMT)-computer-aided molecular design (CAMD) method for the integrated design of the ORC process and working fluid is expanded by a turbine meanline design procedure. Thereby, the search space of the optimization is bounded to regions where the design of the turbine is feasible. The resulting method has been tested for the design of a small-scale high-temperature ORC unit adopting a radial-inflow turbo-expander. The results confirm the potential of the proposed method over the conventional iterative design practice for the design of small-scale ORC turbogenerators.


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