Calculation and Optimization of Heat Transfer between the Low Exergy Heat Source and Organic Rankine Cycle Applied to Heat Recovery Systems

2013 ◽  
Vol 597 ◽  
pp. 45-50
Author(s):  
Sławomir Smoleń ◽  
Hendrik Boertz
Keyword(s):  
Heat Transfer ◽  
Heat Source ◽  
Heat Recovery ◽  
Power Plants ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Optimization Procedure ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Total System

One of the key challenges on the area of energy engineering is the system development for increasing the efficiency of primary energy conversion and use. An effective and important measure suitable for improving efficiencies of existing applications and allowing the extraction of energy from previously unsuitable sources is the Organic Rankine Cycle. Applications based on this cycle allow the use of low temperature energy sources such as waste heat from industrial applications, geothermal sources, biomass, fired power plants and micro combined heat and power systems.Working fluid selection is a major step in designing heat recovery systems based on the Organic Rankine Cycle. Within the framework of the previous original study a special tool has been elaborated in order to compare the influence of different working fluids on performance of an ORC heat recovery power plant installation. A database of a number of organic fluids has been developed. The elaborated tool should create a support by choosing an optimal working fluid for special applications and become a part of a bigger optimization procedure by different frame conditions. The main sorting criterion for the fluids is the system efficiency (resulting from the thermo-physical characteristics) and beyond that the date base contains additional information and criteria, which have to be taken into account, like environmental characteristics for safety and practical considerations.The presented work focuses on the calculation and optimization procedure related to the coupling heat source – ORC cycle. This interface is (or can be) a big source of energy but especially exergy losses. That is why the optimization of the heat transfer between the heat source and the process is (besides the ORC efficiency) of essential importance for the total system efficiency.Within the presented work the general calculation approach and some representative calculation results have been given. This procedure is a part of a complex procedure and program for Working Fluid Selection for Organic Rankine Cycle Applied to Heat Recovery Systems.

Preliminary Design of a Lab-Scale Organic Rankine Cycle for Waste Heat Recovery Applications

2018 ◽  
Author(s):  
Carlos Cabezas ◽  
José Mendoza ◽  
Iván Ponce ◽  
Rafael Cantorin ◽  
Daniel Gonzales ◽  
...  
Keyword(s):  
Heat Source ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Combustion Engine ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Internal Combustion ◽  
Working Fluid ◽  
Preliminary Design

This work describes the preliminary design of a lab-scale organic Rankine cycle (ORC) for waste heat recovery based applications. As heat source for the ORC, exhaust gases from an actual internal combustion engine are utilized. The design is primarily carried out accounting for the working fluid path. More specifically, a brief introduction to be subject is initially provided. The details of the ORC preliminary design are discussed next. This includes the selection of the main working fluid, the definition of the ORC plant layout and the design of the main ORC plant components. The specifics of an overall control loop resembling an actual control system that could be used in the designed ORC based plant is also provided. In terms of power output, the results show that up to 1.68 kW can be produced from the waste heat of internal combustion engines like the one accounted for in this work. Compared to the shaft power (25.1 kW) associated with the internal combustion engine providing the heat source, this power output represents about 7%. The preliminary design described here constitutes the first step of a large effort aiming to build, install and test a lab-scale ORC for educational purposes. It is expected that such ORC based plant allows carrying out in future several studies, including the development of different control strategies for maximizing the operational performance of these plants.

scholarly journals Analysis of heat transfer and irreversibility of organic rankine cycle evaporator for selecting working fluid and operating conditions

2020 ◽  
Vol 24 (3 Part B) ◽  
pp. 2013-2022
Author(s):  
Shuang Ye ◽  
Yan Xu ◽  
Yu Chen ◽  
Wei Huang
Keyword(s):  
Heat Transfer ◽  
Heat Source ◽  
Thermal Resistance ◽  
Heat Transfer Performance ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Transfer Performance ◽  
Irreversible Loss

Organic Rankine cycle (ORC) is suitable to converting the normally hard to utilize low temperature thermal energies, such as geothermal energy, solar energy, and industrial waste heat, to electricity through utilizing low boiling organic working fluids. The performance of ORC system is dramatically affected by the selections of working fluid and working conditions. As a key component of waste heat recovery, the irreversible loss of evaporator also has great influence on the performance of ORC system. In this paper, we study the heat transfer performance in evaporator under the condition that the heat source parameters and pinch point temperature difference are identified. It is found that the heat transfer performance is affected by Cr, the ratio of heat capacity flow rates between the working fluid and the heat source fluid. The equivalent thermal resistance, deducing from the concept of entransy, to measure the irreversability during the heat transfer process is used. Then, the parameter ?r, the ratio between latent heat and sensible heat of working fluid is defined. With the parameters Cr and ?r, we investigate the relationship between the heat transfer and irreversible loss, and deduce the condition that maximum heat transfer and minimum equivalent thermal resistance occurs. Finally, a calculation method is established to choose the optimum working fluid and the evaporation condition.

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

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.

Theoretical and experimental investigation of an organic Rankine cycle for a waste heat recovery system

2009 ◽  
Vol 223 (5) ◽  
pp. 523-533 ◽  
Author(s):  
W Gu ◽  
Y Weng ◽  
Y Wang ◽  
B Zheng
Keyword(s):  
Heat Source ◽  
Entropy Generation ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Entropy Generation Rate ◽  
Working Fluid ◽  
Total Entropy ◽  
Waste Heat Recovery System ◽  
Cycle Efficiency

This article describes and evaluates an organic Rankine cycle (ORC) for a waste heat recovery system by both theoretical and experimental studies. Theoretical analysis of several working fluids shows that cycle efficiency is very sensitive to evaporating pressure, but insensitive to expander inlet temperature. Second law analysis was carried out using R600a as a working fluid and a flow of hot air as a heat source, which is not isothermal, along the evaporator. The result discloses that the evaporator's internal and external entropy generation is the main source of total entropy generation. The effect of the heat source temperature, evaporating pressure, and evaporator size on the entropy generation rate is also presented. The obtained useful power is directly linked to the total entropy generation rate according to the Gouy—Stodola theorem. The ORC testing system was established and operated using R600a as a working fluid and hot water as a heat source. The maximum cycle efficiency of the testing system is 5.2 per cent, and the testing result also proves that cycle efficiency is insensitive to heat source temperature, but sensitive to evaporating pressure. The entropy result also shows that internal and external entropy of the evaporator is the main source of total entropy generation.

Waste Heat Recovery in a Cruise Vessel in the Baltic Sea by Using an Organic Rankine Cycle: A Case Study

2015 ◽  
Author(s):  
Fredrik Ahlgren ◽  
Maria E. Mondejar ◽  
Magnus Genrup ◽  
Marcus Thern
Keyword(s):  
Power Output ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Operating Conditions ◽  
Maritime Transportation ◽  
Working Fluid ◽  
Net Power Output

Maritime transportation is a significant contributor to SOx, NOx and particle matter emissions, even though it has a quite low CO2 impact. New regulations are being enforced in special areas that limit the amount of emissions from the ships. This fact, together with the high fuel prices, is driving the marine industry towards the improvement of the energy efficiency of current ship engines and the reduction of their energy demand. Although more sophisticated and complex engine designs can improve significantly the efficiency of the energy systems in ships, waste heat recovery arises as the most influent technique for the reduction of the energy consumption. In this sense, it is estimated that around 50% of the total energy from the fuel consumed in a ship is wasted and rejected in fluid and exhaust gas streams. The primary heat sources for waste heat recovery are the engine exhaust and the engine coolant. In this work, we present a study on the integration of an organic Rankine cycle (ORC) in an existing ship, for the recovery of the main and auxiliary engines exhaust heat. Experimental data from the operating conditions of the engines on the M/S Birka Stockholm cruise ship were logged during a port-to-port cruise from Stockholm to Mariehamn over a period of time close to one month. The ship has four main engines Wärtsilä 5850 kW for propulsion, and four auxiliary engines 2760 kW used for electrical consumers. A number of six load conditions were identified depending on the vessel speed. The speed range from 12–14 knots was considered as the design condition, as it was present during more than 34% of the time. In this study, the average values of the engines exhaust temperatures and mass flow rates, for each load case, were used as inputs for a model of an ORC. The main parameters of the ORC, including working fluid and turbine configuration, were optimized based on the criteria of maximum net power output and compactness of the installation components. Results from the study showed that an ORC with internal regeneration using benzene would yield the greatest average net power output over the operating time. For this situation, the power production of the ORC would represent about 22% of the total electricity consumption on board. These data confirmed the ORC as a feasible and promising technology for the reduction of fuel consumption and CO2 emissions of existing ships.

Optimization of an Organic Rankine Cycle-Based Waste Heat Recovery System Using a Novel Target-Temperature-Line Approach

2021 ◽  
Vol 143 (9) ◽  
Author(s):  
Md. Zahurul Haq
Keyword(s):  
Heat Exchange ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Optimum Operating ◽  
Working Fluid ◽  
Operating Parameters ◽  
Target Temperature

Abstract Organic Rankine cycle (ORC)-based waste heat recovery (WHR) systems are simple, flexible, economical, and environment-friendly. Many working fluids and cycle configurations are available for WHR systems, and the diversity of working fluid properties complicates the synergistic integration of the efficient heat exchange in the evaporator and net output work. Unique guidelines to select a proper working fluid, cycle configuration and optimum operating parameters are not readily available. In the present study, a simple target-temperature-line approach is introduced to get the optimum operating parameters for the subcritical ORC system. The target-line is the locus of temperatures satisfying the pinch-point temperature difference along the length of the heat exchanger. Employing the approach, study is carried out with 38 pre-selected working fluids to get the optimum operating parameters and suitable fluid for heat source temperatures ranging from 100 °C to 300 °C. Results obtained are analyzed to get cross-correlations between key operating and performance parameters using a heat-map diagram. At the optimum condition, optimal working fluid’s critical temperature and pressure, evaporator saturation temperature, effectivenesses of the heat exchange in the evaporator, cycle, and overall WHR system exhibit strong linear correlations with the heat source temperature.

scholarly journals Economic and Exergo-Advance Analysis of a Waste Heat Recovery System Based on Regenerative Organic Rankine Cycle under Organic Fluids with Low Global Warming Potential

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1317 ◽  
Author(s):  
Guillermo Valencia Ochoa ◽  
Cesar Isaza-Roldan ◽  
Jorge Duarte Forero
Keyword(s):  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Exhaust Gases ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Heat Recovery System

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.

Phase Change Material as Pump in an Organic Rankine Cycle

2014 ◽  
Vol 575 ◽  
pp. 662-667
Author(s):  
Barghav Subramony Hariharan ◽  
Kaushik Suresh
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Electrical Energy ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Change Material

Organic Rankine Cycles (ORC) is predominantly used in waste heat recovery applications because of their low temperature working range. The main efficiency enhancement operation in an Organic Rankine Cycle is reducing the pump work .The pump converts electrical energy to flow energy. This input reduced and output maintained at the same level gives us a more efficient waste heat recovery system. The pump work can also be achieved by using a material that has the ability to expand on heating and revert back to its original state on cooling. The expansion property of the material is used to compress and drive the operating fluid through the cycle. Material that was observed to possess such properties was Phase Change Material. Conventionally PCM were used as thermal storage to preheat the working fluid in an ORC but a novel idea is to make the PCM utilize the heat rejected from the condenser and do the pump work. This paper discusses the various desirable properties of PCM to perform pump work efficiently and also the general layout and working of ORC system using PCM. The working fluid selected is toluene

Organic Rankine Cycle for Waste Heat Recovery in a Hybrid Vehicle

2010 ◽  
Author(s):  
Quazi E. Hussain ◽  
David R. Brigham
Keyword(s):  
Fuel Economy ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Operating Conditions ◽  
Working Fluid ◽  
Drive Cycle ◽  
Exhaust Heat

The Rankine cycle is used commercially to generate power in stationary power plants using water as the working fluid. For waste heat recovery applications, where the temperature is lower, water is typically replaced by a carefully selected organic fluid. This work is based on using the waste heat in an automobile to generate electricity using the Organic Rankine cycle (ORC) with R245fa (1, 1, 1, 3, 3 penta-fluoropropane) as the working fluid. The electricity thus generated can be used to drive the accessory load or charge the battery which in any case helps improve the fuel economy. A simple transient numerical model has been developed that is capable of capturing the main effects of this cycle. Results show that exhaust heat alone can generate enough electricity that is capable of bringing about an improvement to the fuel economy under transient drive cycle conditions. Power output during EPA Highway drive cycle is much higher than EPA City due to higher exhaust mass flow rate and temperature. Time needed to reach operating conditions or in other words, the warm-up time plays an important role in the overall drive cycle output. Performance is found to improve significantly when coolant waste heat is used in conjunction with the residual exhaust heat to pre-heat the liquid. A sizing study is also performed to keep the cost, weight, and packaging requirement down without sacrificing too much power. With careful selection of heat exchanger design parameters, it has been demonstrated that the backpressure on the engine can be actually lowered by cooling off the exhaust gas. This lower backpressure will further boost the fuel economy gained by the electricity produced by the Rankine bottoming cycle.

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