A Control-Oriented ANFIS Model of Evaporator in a 1-kWe Organic Rankine Cycle Prototype

This paper presents a control-oriented neuro-fuzzy model of brazed-plate evaporators for use in organic Rankine cycle (ORC) engines for waste heat recovery from exhaust-gas streams of diesel engines, amongst other applications. Careful modelling of the evaporator is both crucial to assess the dynamic performance of the ORC system and challenging due to the high nonlinearity of its governing equations. The proposed adaptive neuro-fuzzy inference system (ANFIS) model consists of two separate neuro-fuzzy sub-models for predicting the evaporator output temperature and evaporating pressure. Experimental data are collected from a 1-kWe ORC prototype to train, and verify the accuracy of the ANFIS model, which benefits from the feed-forward output calculation and backpropagation capability of the neural network, while keeping the interpretability of fuzzy systems. The effect of training the models using gradient-descent least-square estimate (GDLSE) and particle swarm optimisation (PSO) techniques is investigated, and the performance of both techniques are compared in terms of RMSEs and correlation coefficients. The simulation results indicate strong learning ability and high generalisation performance for both. Training the ANFIS models using the PSO algorithm improved the obtained test data RMSE values by 29% for the evaporator outlet temperature and by 18% for the evaporator outlet pressure. The accuracy and speed of the model illustrate its potential for real-time control purposes.

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Study of Gasoline Engine Waste Heat Recovery by Organic Rankine Cycle

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.383-390.6071 ◽

2011 ◽

Vol 383-390 ◽

pp. 6071-6078

Author(s):

E. H. Wang ◽

H. G. Zhang ◽

B. Y. Fan ◽

H. Liang ◽

M. G. Ouyang

Keyword(s):

Automobile Industry ◽

Gasoline Engine ◽

Waste Heat ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Working Fluid ◽

Outlet Temperature ◽

Exhaust Gas ◽

Environment Protection ◽

The Mathematical Model

Energy saving and environment protection are two important issues that today’s automobile industry must emphasize. Lots of heat energy waste with the exhaust gas when the engine is running. If this part of waste heat can be recovered, the energy efficiency will be improved. Thus plenty of energy can be saved and the global warming also can be reduced. In this paper, the organic Rankine cycle whose working fluid was R245fa was studied. It was adopted to recover the gasoline engine waste heat. The mathematical model of the organic Rankine cycle was built up in Matlab to search the optimized working condition. The pinch analysis method was used to analyze the outlet temperature of the exhaust gas. The results indicate that organic Rankine cycle is a good way to recover the gasoline engine waste heat, especially in the high load conditions. The temperature of the exhaust gas can be apparently decreased.

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On the efficient use of a lowtemperature heat source by the organic Rankine cycle

Archives of Thermodynamics ◽

10.2478/aoter-2013-0015 ◽

2013 ◽

Vol 34 (3) ◽

pp. 61-73 ◽

Cited By ~ 2

Author(s):

Dariusz Mikielewicz ◽

Jarosław Mikielewicz

Keyword(s):

Heat Source ◽

Single Phase ◽

Waste Heat ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Outlet Temperature ◽

Fluid Temperature ◽

Flow Rates ◽

Waste Heat Utilization ◽

Analytical Expressions

Abstract The evaporation temperature is regarded as one of the major parameters influencing the organic Rankine cycle (ORC) efficiency. Majority of contributions in literature for ORC cycle analyses treat the heat source as if it had an infinite heat capacity. Such analyses are not valuable as the resulting temperature drops of the heat source needs to be small. That leads to the fact that the heat source is not well explored and in the case of waste heat utilization it can prove the poor economics of the ORC. In the present study cooperation of the ORC cycle with the heat source available as a single phase or phase changing fluids is considered. The analytical heat balance models have been developed, which enable in a simple way calculation of heating fluid temperature variation as well as the ratio of flow rates of heating and working fluids in ORC cycle. The developed analytical expressions enable also calculation of the outlet temperature of the heating fluid.

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An Innovative Application of a Solar Storage Wall Combined with the Low-Temperature Organic Rankine Cycle

International Journal of Photoenergy ◽

10.1155/2014/239137 ◽

2014 ◽

Vol 2014 ◽

pp. 1-12 ◽

Cited By ~ 2

Author(s):

Tzu-Chen Hung ◽

Duen-Sheng Lee ◽

Jaw-Ren Lin

Keyword(s):

Waste Heat ◽

Ventilation System ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Operating Conditions ◽

Critical Parameters ◽

Thermal Engineering ◽

Outlet Temperature ◽

Low Carbon ◽

Ventilation Systems

The objective of this study is to collect energy on the waste heat from air produced by solar ventilation systems. This heat used for electricity generation by an organic Rankine cycle (ORC) system was implemented. The advantages of this method include the use of existing building’s wall, and it also provides the region of energy scarcity for reference. This is also an innovative method, and the results will contribute to the efforts made toward improving the design of solar ventilation in the field of solar thermal engineering. In addition, ORC system would help generate electricity and build a low-carbon building. This study considered several critical parameters such as length of the airflow channel, intensity of solar radiation, pattern of the absorber plate, stagnant air layer, and operating conditions. The simulation results show that the highest outlet temperature and heat collecting efficiency of solar ventilation system are about 120°C and 60%, respectively. The measured ORC efficiency of the system was 6.2%. The proposed method is feasible for the waste heat from air produced by ventilation systems.

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Zeotropic Mixture Selection for an Organic Rankine Cycle Using a Single Screw Expander

Energies ◽

10.3390/en13051022 ◽

2020 ◽

Vol 13 (5) ◽

pp. 1022

Author(s):

Xinxin Zhang ◽

Yin Zhang ◽

Zhenlei Li ◽

Jingfu Wang ◽

Yuting Wu ◽

...

Keyword(s):

Heat Source ◽

Waste Heat ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Energy Utilization ◽

Working Fluid ◽

Low Grade ◽

Outlet Temperature ◽

Single Screw ◽

Zeotropic Mixture

The organic Rankine cycle (ORC) is a popular and promising technology that has been widely studied and adopted in renewable and sustainable energy utilization and low-grade waste heat recovery. The use of zeotropic mixtures in ORC has been attracting more and more attention because of the possibility to match the temperature profile of the heat source by non-isothermal phase change, which reduces the irreversibility in the evaporator and the condenser. The selection of working fluid and expander is strongly interconnected. As a novel expander, a single screw expander was selected and used in this paper for efficient utilization of the wet zeotropic mixtures listed in REFPROP 9.1 in a low-temperature subcritical ORC system. Five indicators, namely net work, thermal efficiency, heat exchange load of condenser, temperature glide in evaporator, and temperature glide in condenser, were used to analyze the performance of an ORC system with wet and isentropic zeotropic mixtures as working fluids. The calculation and analysis results indicate that R441A with an expander outlet temperature of 320 K may be the suitable zeotropic mixture used for both open and close type heat source. R436B may be selected with an expander outlet temperature of 315 K. R432A may be selected with an expander outlet temperature from 295 K to 310 K.

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Waste Heat Rejection Systems for Organic Rankine Cycle Dynamic Isotope Power System

22nd Intersociety Energy Conversion Engineering Conference ◽

10.2514/6.1987-9050 ◽

1987 ◽

Author(s):

T. J. Bland ◽

W. J. Greenlee ◽

K. Clodfelter

Keyword(s):

Power System ◽

Waste Heat ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Heat Rejection

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Component-Oriented Modeling of a Micro-Scale Organic Rankine Cycle System for Waste Heat Recovery Applications

Applied Sciences ◽

10.3390/app11051984 ◽

2021 ◽

Vol 11 (5) ◽

pp. 1984

Author(s):

Ramin Moradi ◽

Emanuele Habib ◽

Enrico Bocci ◽

Luca Cioccolanti

Keyword(s):

Electric Power ◽

Heat Recovery ◽

Waste Heat Recovery ◽

Waste Heat ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Operating Conditions ◽

Working Fluid ◽

Pump Efficiency ◽

Micro Scale

Organic Rankine cycle (ORC) systems are some of the most suitable technologies to produce electricity from low-temperature waste heat. In this study, a non-regenerative, micro-scale ORC system was tested in off-design conditions using R134a as the working fluid. The experimental data were then used to tune the semi-empirical models of the main components of the system. Eventually, the models were used in a component-oriented system solver to map the system electric performance at varying operating conditions. The analysis highlighted the non-negligible impact of the plunger pump on the system performance Indeed, the experimental results showed that the low pump efficiency in the investigated operating range can lead to negative net electric power in some working conditions. For most data points, the expander and the pump isentropic efficiencies are found in the approximate ranges of 35% to 55% and 17% to 34%, respectively. Furthermore, the maximum net electric power was about 200 W with a net electric efficiency of about 1.2%, thus also stressing the importance of a proper selection of the pump for waste heat recovery applications.

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Organic Rankine cycle for turboprop engine application

The Aeronautical Journal ◽

10.1017/aer.2021.32 ◽

2021 ◽

pp. 1-21

Author(s):

G.E. Pateropoulos ◽

T.G. Efstathiadis ◽

A.I. Kalfas

Keyword(s):

Waste Heat ◽

Organic Rankine Cycle ◽

Weight Ratio ◽

Rankine Cycle ◽

Aircraft Engine ◽

Working Fluid ◽

Engine Fuel ◽

Exhaust Gases ◽

Waste Heat Recovery System ◽

Turboprop Engine

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.

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