The Potential of Mixtures of Pure Fluids in ORC-based Power Units fed by Exhaust Gases in Internal Combustion Engines (original) (raw)
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Thermodynamic Analysis of ORC Configurations Used for WHR from a Turbocharged Diesel Engine
Procedia Engineering, 2015
This paper illustrates a comparison between different solutions for waste heat recovery from a specific internal combustion engine using an Organic Rankine Cycle (ORC). The purpose of the present work is to find the cycle configuration and the fluid that can provide the maximum mechanical power for given conditions of waste heat recovery (WHR) from flue gas and motor cooling water of a Turbocharged Diesel Engine Electric Generator. The thermodynamic analysis is conducted for ten working fluids from different chemical classes: hydrofluorocarbons (HFC) and the new subclass hydrofluoroolefins (HFO), hydrocarbons (HC), siloxanes and alcohols applied on six ORC configurations, three conventional ones (basic ORC, regenerative ORC and preheater ORC), a regenerative dual-loop ORC (DORC), a mixture of two traditional ORC (one used for WHR from the motor cooling water and the other used for flue gas WHR) and a dual ORC but with a common condenser configuration. One of the working fluids investigated is a new HFO, named R1336mzz, which has very low GWP, zero ODP and good safety properties. This novel fluid also shows good results in our investigation. Future work and development perspectives are discussed.
Revista de Chimie
The present works deals with waste heat recovery from internal combustion engines using Rankine cycle systems where working fluid are organic liquids (ORC). The first part of the paper presents the ORC technology as one of the most suitable procedure for waste heat recovery from exhaust gas of internal combustion engine (ICE). The particular engine considered in the present work is a turbocharged compression ignition engine mounted on an experimental setup. The working fluids for ORC system are: isobutene, propane, RE245fa2, RE245cb2, R245fa, R236fa, R365mfc, R1233zd(E), R1234yf and R1234ze(Z). Experimental data derived from the experimental setup has been used for 40%, 55% and 70% engine load. This papers focusses on superheating increment, on thermal efficiency and on net power output, obtained with each working fluids in Rankine cycle. Results point out the superheating increment that gives the highest thermal efficiency for each working fluid. The highest thermal efficiency is a...
International Journal of Energy Research, 2019
With the temperature glide in saturation states, the mixture working fluids have the advantages in thermal energy conversion. In this study, through the investigation in optimum mass fractions of multicomponent mixture working fluids, the economic performance enhancement of the organic Rankine cycle system is obtained for recovering waste heat from engine. The zero ozonedepletion-potential and dry working fluids of R236fa, R245fa, and R1336mzz (Z) are selected as the components of multicomponent mixtures in the system. The net power output, heat transfer calculation, and apparatus cost evaluation are employed to evaluate the power cost of the organic Rankine cycle system. Parameters of temperatures of waste heat sources and efficiencies of expanders are taken into account. The comparisons of economic performances for singlecomponent working fluid and multicomponent mixtures with optimum mass fractions are proposed. The results show that R245fa, having a levelized cost of energy, LCOE, of 8.75 × 10 −2 /kW−h,performsthebestforsingle−componentworkingfluids,betterthanR236faby1.6/kW-h, performs the best for single-component working fluids, better than R236fa by 1.6% and R1336mzz(Z) by 8.3%. All the two-component mixtures are superior to their single-component working fluids in economic performance. Among the three two-component mixture working fluids, R1336mzz(Z)/R236fa has the lowest LCOE min , 8.57 × 10 −2 /kW−h,performsthebestforsingle−componentworkingfluids,betterthanR236faby1.6/kW-h, followed by R236fa/R245fa and R245fa/R1336mzz(Z). In addition, R236fa/R245fa/R1336mzz(Z) mixture, which has a LCOE min of 8.47 × 10 −2 $/kW-h, economically outperforms all other working fluids and has a lower LCOE min than R236fa/R245fa by 1.7% and R245fa/R1336mzz(Z) by 2%.
Applied Thermal Engineering, 2017
In this study, exergy analysis of a two-parallel-step organic Rankine cycle (ORC) for waste heat recovery from an internal combustion engine (ICE) is performed. A novel two-step configuration to recover waste heat from the engine coolant fluid and the exhaust gas simultaneously is first introduced. The working fluids considered for this heat recovery system are R-123, R-134a, and water. A comprehensive thermodynamic modeling of the cycle was performed and optimization of the system was carried out to observe the simultaneous effect of key design parameters on the system performance. The net output power and the exergy efficiency were used as the objective functions with a goal of maximizing them. The design variables for this study are the first and second step pressures of the cycle, the pump and the expander isentropic efficiencies, and the exhaust gas temperature after waste heat recovery. The results show R-123 as the best working fluid under the considered conditions, which generates 468 kW of net output power with an exergy efficiency of 21%. A sensitivity study was also performed on the optimized design to identify the component that impacts the ORC performance the most.
Thermodynamic Analysis of a Combined Gas Turbine ORC Using Some Organic Fluids
Bitlis Eren üniversitesi fen bilimleri dergisi, 2022
The increase in energy and environmental problems has led us to use sustainable methods for the optimization of energy systems. In this study, an integrated Organic Rankine Cycle (ORC) has been added to the waste heat of a cascade expansion gas turbine in the name of innovative concepts in industrial competition. In this ORC system, mass flow rates, pressure ratios, net powers and thermodynamic calculations of five different fluids (R123, R245fa, R600, R365mfc and R113) were made by operating them with a certain heat load. Accordingly, the ORC net powers of the refrigerants were found to be 15.54kW for R123, 14.78kW for R245fa, 14.71kW for R600, 14.78kW for R365mfc and 15.45kW for R113. With the net power of 51.4kW from the gas turbine, the net power obtained with the R123 refrigerant used in the ORC system is added to 15.54 kW and it has been calculated that it provides a total net power of 66.94kW. The energy efficiency of the designed integrated system was calculated as 66% and the exergy efficiency as 20%. It is seen that the importance of sustainable energy in the optimization of power systems combined with ORC is inevitable.
An experimental and modelling study of a 1 kW organic Rankine cycle unit with mixture working fluid
Energy, 2015
The ORC (organic Rankine cycle) technology is appropriate for conversion of low-grade industrial waste heat to electrical power due to its utilization of volatile organic fluids as working fluids. It has been proposed that zeotropic fluid mixtures can improve the ORC performance compared to pure fluids. The purpose of this paper was to demonstrate the feasibility of using a zeotropic mixture as working fluid through an experimental study with a lab-scale ORC (organic Rankine cycle) test rig. In this study, a zeotropic mixture of R245fa and R365mfc (48.5%/51.5% on a mole basis) was examined by focusing on its dynamic behavior in the system until reaching steady state and the performance in a scroll expander, a finned-tube heat extractor, an evaporator and a condenser. The test rig used the exhaust gas from a 30 kW Capstone™ Gas Turbine as its heat source. Computer simulation was conducted at system level with steady state conditions and the results were compared to experimental data.
Second law analysis of zeotropic mixtures as working fluids in organic Rankine cycles
To improve the thermal performance of the basic organic Rankine cycle (ORC) several modifications are proposed in literature. One of these modifications is the use of zeotropic mixtures as working fluids. Zeotropic mixtures as working fluids have the ability to better match the heating (cooling) temperature profiles of the heat source (heat sink). As a result the irreversibilities associated with a finite temperature thermal heat transfer are reduced. In a previous study a first law mixture selection method was proposed, considering most of the commonly used hydrocarbons and siloxane substances as components in various mixture concentrations. This paper extends the previous study by comparing the basic ORC and the ORC with zeotropic mixtures as working fluids based on a second law analysis. The zeotropic mixtures under study are: R245fa-pentane, R245fa-R365mfc, isopentane-isohexane, isopentane-cyclohexane, isopentane-isohexane, isobutane-isopentane and pentane-hexane. The exergetic efficiency, defined as the ratio of shaft power output and input waste heat exergy, is used as optimization criterion. Furthermore, the irreversibilities associated with the different components of the ORC are assessed under different mixture compositions. Next, the optimization potential when using zeotropic mixtures is thoroughly discussed. The results show that the evaporator amounts for the highest exergy loss. However, the best performance is achieved when the condenser heat profiles are matched. A relative increase of exergetic efficiency between 7.1% and 14.2% is found for a waste heat source at 150 °C. The ORC with isobutane-isopentane as working fluid has the highest second law efficiency (32.05%) under optimal mixture concentration and evaporation pressure.
Thermodynamic and technical criteria for the optimal selection of the working fluid in a mini-ORC
2016
Waste energy recovery (WER) is a suitable solution to improve the fuel utilization of Internal Combustion Engines (ICEs) by producing an eco-friendly electrical power from an energy source currently wasted. Organic Rankine Cycle (ORC) technology has been developed in the past few years to generate electric power from medium temperature (500 K – 800 K) ICE wasted thermal sources. Working fluid selection represents the first step in the design of an ORC. At the state of the art, authors where not able to select a single optimal organic fluid. This is mainly because of the different thermodynamic conditions of the heat sources which offer wasted thermal energy. This paper proposes a procedure for the ORC system preliminary working fluid selection, which takes into consideration thermodynamics and design parameters of the system components. The study is applied to WER systems specifically designed as bottoming cycles to ICE for transport applications. However, the method is quite genera...
IOP conference series, 2018
The paper deals with waste heat recovery (WHR) from internal combustion engines (ICE) using organic Rankine cycle based systems (ORC), due to its ability to operate with moderate temperature differences. The waste heat source is flue gas from an ICE that drives a stationary electric generator. The configuration of the ORC system is the basic one. The mathematical modelling of the ICE-ORC system is a continuation of previous work conducted by the authors and has been validated by using as input, data from other similar papers. The results are in good agreement. The mathematical model has also been used as part of a working fluid selection procedure for the ORC system. The working fluid selection procedure is based on screening fifteen candidate fluids and selecting the most suitable ones by using three criteria: environmental, safety and technical. A discussion about the type of working fluid is conducted. The screened working fluids are R134a,