PRESENTATION OF A TEST-RIG FOR HEAT TRANSFER MEASUREMENTS OF A FLUID AT SUPERCRITICAL STATE FOR ORGANIC RANKINE CYCLE APPLICATION

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.

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Thermo-Economic and Heat Transfer Optimization of Working-Fluid Mixtures in a Low-Temperature Organic Rankine Cycle System

Energies ◽

10.3390/en9060448 ◽

2016 ◽

Vol 9 (6) ◽

pp. 448 ◽

Cited By ~ 58

Author(s):

Oyeniyi Oyewunmi ◽

Christos Markides

Keyword(s):

Heat Transfer ◽

Low Temperature ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Working Fluid ◽

Fluid Mixtures ◽

Cycle System ◽

Heat Transfer Optimization

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Performance of Siloxane Mixtures in a High-Temperature Organic Rankine Cycle Considering the Heat Transfer Characteristics during Evaporation

Energies ◽

10.3390/en7095548 ◽

2014 ◽

Vol 7 (9) ◽

pp. 5548-5565 ◽

Cited By ~ 25

Author(s):

Theresa Weith ◽

Florian Heberle ◽

Markus Preißinger ◽

Dieter Brüggemann

Keyword(s):

Heat Transfer ◽

High Temperature ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Heat Transfer Characteristics ◽

Transfer Characteristics

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A COMPREHENSIVE ENERGETIC, EXERGETIC AND HEAT TRANSFER ANALYSIS OF A SOLAR ORGANIC RANKINE SYSTEM

Revista de Engenharia Térmica ◽

10.5380/reterm.v20i1.80464 ◽

2021 ◽

Vol 20 (1) ◽

pp. 100

Author(s):

A. E. Achiles ◽

J. V. H. D’Angelo

Keyword(s):

Heat Transfer ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Heat Transfer Analysis ◽

Environmental Concerns ◽

Power Block ◽

Transfer Behavior ◽

Organic Rankine Cycles ◽

Solar Resource ◽

Solar Field

Environmental concerns have been motivating the use of renewable energysources to meet sustainable requirements. In this context, concentrated solarpower driven by organic Rankine cycles has been classified as an up-andcomingtechnology to generate energy under low and moderate temperatures.In order to have a better understanding of the availability and utilization of thisenergy resource, the purpose of the present study is to perform acomprehensive energetic, exergetic and heat transfer analysis of a 200 kWsolar organic Rankine cycle through the presentation of the energy and exergyefficiencies and losses for each component; the exergy destruction at all stagesof the process; and the heat transfer behavior along the receiver. The thermalmodel was developed in Engineering Equation Solver and validated withliterature data. The solar collector was operated with Therminol 66 and theworking fluid employed in the power block was cyclohexane. The energeticefficiencies achieved in the solar field, power block, and overall system were64.97; 21.36; and 13.87 %, respectively. Considering the exergetic efficiencies,they were 27.37; 54.45; and 14.89 %, respectively. The solar resource variationshowed that the higher DNI value, the better the system performance.

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Multi-objective optimization of CuO based organic Rankine cycle operated using R245ca

E3S Web of Conferences ◽

10.1051/e3sconf/201911600062 ◽

2019 ◽

Vol 116 ◽

pp. 00062 ◽

Cited By ~ 1

Author(s):

Parth Prajapati ◽

Vivek Patel

Keyword(s):

Heat Transfer ◽

Thermal Efficiency ◽

Heat Exchangers ◽

Waste Heat ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Working Fluid ◽

Multi Objective Optimization ◽

Multi Objective ◽

Source Fluid

The present work deals with multi objective optimization of nanofluid based Organic Rankine Cycle (ORC) to utilise waste heat energy. Working fluid considered for the study is R245ca for its good thermodynamic properties and lower Global Warming Potential (GWP) compared to the conventional fluids used in the waste heat recovery system. Heat Transfer Search (HTS) algorithm is used to optimize the objective functions which tends to maximize thermal efficiency and minimize Levelised Energy Cost (LEC). To enhance heat transfer between the working fluid and source fluid, nanoparticles are added to the source fluid. Application of nanofluids in the heat transfer system helps in maximizing recovery of the waste heat in the heat exchangers. Based on the availability and cost, CuO nanoparticles are considered for the study. Effect of Pinch Point Temperature Difference (PPTD) and concentration of nanoparticles in heat exchangers is studied and discussed. Results showed that nanofluids based ORC gives maximum thermal efficiency of 18.50% at LEC of 2.59 $/kWh. Total reduction of 7.11% in LEC can be achieved using nanofluids.

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Modelling of Polymeric Shell and Tube Heat Exchangers for Low-Medium Temperature Geothermal Applications

Energies ◽

10.3390/en13112737 ◽

2020 ◽

Vol 13 (11) ◽

pp. 2737

Author(s):

Francesca Ceglia ◽

Adriano Macaluso ◽

Elisa Marrasso ◽

Maurizio Sasso ◽

Laura Vanoli

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Heat Exchangers ◽

Power Plants ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Working Fluid ◽

Heat Transfer Area ◽

Geothermal Fluid ◽

Shell And Tube

Improvements in using geothermal sources can be attained through the installation of power plants taking advantage of low and medium enthalpy available in poorly exploited geothermal sites. Geothermal fluids at medium and low temperature could be considered to feed binary cycle power plants using organic fluids for electricity “production” or in cogeneration configuration. The improvement in the use of geothermal aquifers at low-medium enthalpy in small deep sites favours the reduction of drilling well costs, and in addition, it allows the exploitation of local resources in the energy districts. The heat exchanger evaporator enables the thermal heat exchange between the working fluid (which is commonly an organic fluid for an Organic Rankine Cycle) and the geothermal fluid (supplied by the aquifer). Thus, it has to be realised taking into account the thermodynamic proprieties and chemical composition of the geothermal field. The geothermal fluid is typically very aggressive, and it leads to the corrosion of steel traditionally used in the heat exchangers. This paper analyses the possibility of using plastic material in the constructions of the evaporator installed in an Organic Rankine Cycle plant in order to overcome the problems of corrosion and the increase of heat exchanger thermal resistance due to the fouling effect. A comparison among heat exchangers made of commonly used materials, such as carbon, steel, and titanium, with alternative polymeric materials has been carried out. This analysis has been built in a mathematical approach using the correlation referred to in the literature about heat transfer in single-phase and two-phase fluids in a tube and/or in the shell side. The outcomes provide the heat transfer area for the shell and tube heat exchanger with a fixed thermal power size. The results have demonstrated that the plastic evaporator shows an increase of 47.0% of the heat transfer area but an economic installation cost saving of 48.0% over the titanium evaporator.

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