References of "Quoilin, Sylvain"
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See detailOrganic Rankine Cycles including fluid selection
Lemort, Vincent ULg; Declaye, Sébastien ULg; Quoilin, Sylvain ULg

in Handbook of Clean Energy Systems (in press)

An Organic Rankine Cycle (ORC) is similar to a steam Rankine cycle, except that the working fluid is not water but an organic compound, such as a refrigerant or a hydrocarbon, characterized by a lower ... [more ▼]

An Organic Rankine Cycle (ORC) is similar to a steam Rankine cycle, except that the working fluid is not water but an organic compound, such as a refrigerant or a hydrocarbon, characterized by a lower ebullition temperature than that of water. Hence lower temperature heat sources can be exploited such as solar energy, geothermal energy and waste heat recovery from many different processes. During the design phase of an ORC system, the selection of the working fluid must be conducted in parallel with the selection and the sizing of the components (mainly the expansion machine, the pump and the heat exchangers) and with the definition of the cycle architecture. This approach allows taking into consideration all technical constraints. Relevant properties of working fluids that should be considered during their selection are listed. Major characteristics of available displacement and turbo-expander technologies are described. The impact of the pump performance on the overall performance is discussed and strategies to increase the available NPSH are proposed. Finally, improved cycle architectures are introduced. Major applications of ORC systems are described: geothermal power plants, biomass CHP plants, waste heat recovery in industry, waste heat recovery on internal combustion engines and solar power plants. All these applications differ by the nature of the heat source and heat sink, the integration of the ORC with these sources and sinks, and the range of installed capacities. These differences yield specific designs, which are described. Performance achieved by systems in operation or prototypes are presented. [less ▲]

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See detailThe importance of open data and software: Is energy research lagging behind?
Pfenninger, Stefan; DeCariolis, Joseph; Hirth, Lion et al

in Energy Policy (2017)

Energy policy often builds on insights gained from quantitative energy models and their underlying data. As climate change mitigation and economic concerns drive a sustained transformation of the energy ... [more ▼]

Energy policy often builds on insights gained from quantitative energy models and their underlying data. As climate change mitigation and economic concerns drive a sustained transformation of the energy sector, transparent and well-founded analyses are more important than ever. We assert that models and their associated data must be openly available to facilitate higher quality science, greater productivity through less duplicated effort, and a more effective science-policy boundary. There are also valid reasons why data and code are not open: ethical and security concerns, unwanted exposure, additional workload, and institutional or personal inertia. Overall, energy policy research ostensibly lags behind other fields in promoting more open and reproducible science. We take stock of the status quo and propose actionable steps forward for the energy research community to ensure that it can better engage with decision-makers and continues to deliver robust policy advice in a transparent and reproducible way. [less ▲]

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See detailTechno-economic evaluation of self-consumption with PV/battery systems under different regulation schemes
Quoilin, Sylvain ULg; Zucker, Andreas

in Proceedings of the 29th international conference on Efficiency, Cost, Optimisation, Simulation and Environmental Impact of Energy Systems (2016, July)

The recent disclosure of new and innovative home battery systems has been seen by many as a catalyser for a solar energy revolution, and has created high expectations in the sector. Many observers have ... [more ▼]

The recent disclosure of new and innovative home battery systems has been seen by many as a catalyser for a solar energy revolution, and has created high expectations in the sector. Many observers have predicted an uptake of combined PV/Battery units, which, could ultimately disconnect from the grid and lead to autonomous homes or mini-grids. However, most of the comments originating from social media, blogs or press articles lack proper cost evaluation and realistic simulations. This work aims at bridging this gap by simulating self-consumption in different EU countries, for different household profiles with or without battery. Results indicate that (1) Although decreasing at a fast pace, the cost of domestic Li-Ion storage is most likely still too high for a large-scale market uptake in Europe; (2) PV incentives based on net metering are not favourable to home batteries; (3) Home battery profitability and future uptake mainly depend on the indirect self-consumption subsidies provided by the structure of the retail prices; (4) These systems do not allow residential consumers to go off-grid. They only allow for a maximum self-sufficiency ratio close to 70%. [less ▲]

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See detailORCmKit: an open-source library for organic Rankine cycle modelling and analysis
Dickes, Rémi ULg; Ziviani, Davide; van den Broek, Martjin et al

in Proceedings of ECOS 2016 (2016, June 20)

As for many other technologies, modelling and simulation of organic Rankine cycles (ORCs) are crucial for design, optimization and control purposes. However, model development is often time consuming and ... [more ▼]

As for many other technologies, modelling and simulation of organic Rankine cycles (ORCs) are crucial for design, optimization and control purposes. However, model development is often time consuming and the scientific community lacks of open-access tools to study ORC systems. For these reasons, researchers from the universities of Liège and Ghent in Belgium gathered their knowledge and created “ORC modelling Kit” (ORCmKit), an open-source library dedicated to the steady-state simulation and analysis of organic Rankine cycles. Both component-level and cycle-level models are provided and different ORC architectures can be simulated. For each of the main component of ORC systems, different models are available with increasing complexity which allows a wide range of modelling possibilities. In order to remain general and accessible to as many people as possible, three widely used programming languages are covered within ORCmKit, i.e. Matlab, Python and EES (Engineering Equation Solver). Besides source codes, ORCmKit also includes calibration tools for empirical and semi-empirical models as well as a complete documentation for ease of use. [less ▲]

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See detailOrganic Rankine cycle modelling and the ORCmKit library: analysis of R1234ze(Z) as drop-in replacement of R245fa for low-grade waste heat recovery
Ziviani, Davide; Dickes, Rémi ULg; Quoilin, Sylvain ULg et al

in Proceedings of ECOS 2016 (2016, June 20)

Due to the wide interest in organic Rankine cycles (ORCs) as a sustainable technology and the importance of numerical analyses and optimization procedures while considering such systems, we created a ... [more ▼]

Due to the wide interest in organic Rankine cycles (ORCs) as a sustainable technology and the importance of numerical analyses and optimization procedures while considering such systems, we created a dedicated open-source library named “ORC modelling Kit” (ORCmKit). The comprehensive library includes single com-ponents and overall models for subcritical, transcritical and supercritical ORCs. Three main programming environments are currently supported: Matlab, Python and EES (Engineering Equation Solver). A detailed steady-state cycle model of a small-scale regenerative ORC with a single-screw expander is used to evalu-ate the performance influence of R1234ze(Z) as a drop-in replacement of R245fa currently used in the instal-lation. The ORC system is used to recover low-grade waste heat with a temperature range between 90°C and 120°C. A thermal oil heater is used to simulate the heat source. A parametric study is carried out to in-vestigate the performance of the system throughout the range of interest in order to optimize the ORC with R1234ze(Z). [less ▲]

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See detailAssessing steady-state, multivariate experimental data using Gaussian Processes: the GPExp open-source library
Quoilin, Sylvain ULg; Schrouff, Jessica ULg

in Energies (2016), 9(6),

Experimental data are subject to different sources of disturbance and errors, whose importance should be assessed. The level of noise, the presence of outliers or a measure of the “explainability” of the ... [more ▼]

Experimental data are subject to different sources of disturbance and errors, whose importance should be assessed. The level of noise, the presence of outliers or a measure of the “explainability” of the key variables with respect to the externally-imposed operating condition are important indicators, but are not straightforward to obtain, especially if the data are sparse and multivariate. This paper proposes a methodology and a suite of tools implementing Gaussian processes for quality assessment of steady-state experimental data. The aim of the proposed tool is to: (1) provide a smooth (de-noised) multivariate operating map of the measured variable with respect to the inputs; (2) determine which inputs are relevant to predict a selected output; (3) provide a sensitivity analysis of the measured variables with respect to the inputs; (4) provide a measure of the accuracy (confidence intervals) for the prediction of the data; (5) detect the observations that are likely to be outliers. We show that Gaussian processes regression provides insightful numerical indicators for these purposes and that the obtained performance is higher or comparable to alternative modeling techniques. Finally, the datasets and tools developed in this work are provided within the GPExp open-source package. [less ▲]

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See detailExperimental comparison of organic fluids for low temperature ORC (organic Rankine cycle) systems for waste heat recovery applications
Desideri, Adriano ULg; Gusev, Sergei; Van den Broek, Martijn et al

in Energy (2016), 97

This contribution experimentally evaluates and compares the performance of an ORC (organic Rankine cycle) system for stationary bottoming WHR (waste heat recovery) application operating with two different ... [more ▼]

This contribution experimentally evaluates and compares the performance of an ORC (organic Rankine cycle) system for stationary bottoming WHR (waste heat recovery) application operating with two different working fluids, SES36 and R245fa. The test rig is a regenerative cycle equipped with a single screw expander modified from a standard compressor characterized by a nominal shaft power of 11 kW. A total of 36 and 43 steady-state points are collected for SES36 and R245fa respectively, over a wide range of operating conditions by changing the expander rotational speed, the pump frequency and the cooling condenser flow rate. The performances of the ORC components are individually evaluated. A maximum expander isentropic efficiency of 60% is reached using SES36 at 3000 rpm, and a value of 52% is reached with R245fa at 3000 rpm. However, for a given pressure ratio the expander output power is higher with R245fa than with SES36. The overall performance of the ORC unit are investigated in terms of first and second law efficiencies and net output power for the two fluids. The results experimentally demonstrate the correlation between the working fluid critical temperature and the ORC unit working characteristics for low temperature waste heat recovery applications. Open experimental data are provided for both fluids. [less ▲]

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See detailPerformance of a reversible heat pump/organic Rankine cycle unit coupled with a passive house to get a positive energy building
Dumont, Olivier ULg; Carmo, Carolina; Fontaine, Valentin et al

in Journal of Building Performance Simulation [=JBPS] (2016)

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See detailCategorization and analysis of heat sources for organic Rankine cycle systems
Zhai, Huixing; An, Qingsong; Shi, Lin et al

in Renewable and Sustainable Energy Reviews (2016)

Organic Rankine cycles (ORC) are an effective way to convert low-medium temperature heat to electricity that cannot be used for conventional high-temperature Rankine cycles. Even though there has been ... [more ▼]

Organic Rankine cycles (ORC) are an effective way to convert low-medium temperature heat to electricity that cannot be used for conventional high-temperature Rankine cycles. Even though there has been many studies of ORC systems over the past few decades, ORC heat sources have received relatively little attention. The heat sources providing energy to the ORC have different characteristics that significantly impact the theoretical analyses and system designs of ORC systems. This paper gives a theoretical categorization of heat sources to give uniform boundary conditions for further theoretical studies on cycle choices and working fluid screening. The ideal cycles for each heat source type are analyzed. Performance metrics are recommended for different heat source ORC systems. The general characteristics of the different heat sources including waste heat from industrial and power systems and geothermal, solar and biomass sources are given with their influences on the ORC systems. Finally, the market characteristics for ORC systems using different heat sources are reviewed with suggestions for future developments of ORC systems. [less ▲]

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See detailEconomic assessment of electric energy storage for load shifting in positive energy building
Dumont, Olivier ULg; Carmo, Carolina; Georges, Emeline ULg et al

in International Journal of Energy and Environmental Engineering (2016)

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See detailQuantifying self-consumption linked to solar home battery systems: Statistical analysis and economic assessment
Quoilin, Sylvain ULg; Kavvadias, Konstantinos; Mercier, Arnaud et al

in Applied Energy (2016)

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See detailHot water tanks : how to select the optimal modelling approach?
Dumont, Olivier ULg; Carmo, Carolina; Dickes, Rémi ULg et al

Conference (2016)

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See detailReal-Time Optimization of Organic Rankine Cycle Systems by Extremum-Seeking Control
Hernandez Naranjo, Jairo Andres ULg; Desideri, Adriano ULg; Ionescu, Clara et al

in Energies (2016), 9

In this paper, the optimal operation of a stationary sub-critical 11kWel organic Rankine cycle (ORC) unit for waste heat recovery (WHR) applications is investigated, both in terms of energy production and ... [more ▼]

In this paper, the optimal operation of a stationary sub-critical 11kWel organic Rankine cycle (ORC) unit for waste heat recovery (WHR) applications is investigated, both in terms of energy production and safety conditions. Simulation results of a validated dynamic model of the ORC power unit are used to derive a correlation for the evaporating temperature, which maximizes the power generation for a range of operating conditions. This idea is further extended using a perturbation-based extremum seeking (ES) algorithm to identify online the optimal evaporating temperature. Regarding safety conditions, we propose the use of the extended prediction self-adaptive control (EPSAC) approach to constrained model predictive control (MPC). Since it uses input/output models for prediction, it avoids the need for state estimators, making it a suitable tool for industrial applications. The performance of the proposed control strategy is compared to PID-like schemes. Results show that EPSAC-MPC is a more effective control strategy, as it allows a safer and more efficient operation of the ORC unit, as it can handle constraints in a natural way, operating close to the boundary conditions where power generation is maximized. [less ▲]

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See detailComparison of Moving Boundary and Finite-Volume Heat Exchanger Models in the Modelica Language
Desideri, Adriano ULg; Dechesne, Bertrand ULg; Wronski, Jorrit et al

in energies (2016)

When modeling low capacity energy systems, such as a small size (5–150kWel) organic Rankine cycle unit, the governing dynamics are mainly concentrated in the heat exchangers. As a consequence, the ... [more ▼]

When modeling low capacity energy systems, such as a small size (5–150kWel) organic Rankine cycle unit, the governing dynamics are mainly concentrated in the heat exchangers. As a consequence, the accuracy and simulation speed of the higher level system model mainly depend on the heat exchanger model formulation. In particular, the modeling of thermo-flow systems characterized by evaporation or condensation requires heat exchanger models capable of handling phase transitions. To this aim, the finite volume (FV) and the moving boundary (MB) approaches are the most widely used. The two models are developed and included in the open-source ThermoCycle Modelica library. In this contribution, a comparison between the two approaches is presented. An integrity and accuracy test is designed to evaluate the performance of the FV and MB models during transient conditions. In order to analyze how the two modeling approaches perform when integrated at a system level, two organic Rankine cycle (ORC) system models are built using the FV and the MB evaporator model, and their responses are compared against experimental data collected on an 11kWel ORC power unit. Additionally, the effect of the void fraction value in the MB evaporator model and of the number of control volumes (CVs) in the FV one is investigated. The results allow drawing general guidelines for the development of heat exchanger dynamic models involving two-phase flows. [less ▲]

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See detailTechno-economic optimization of isolate micro-grids including PV and Li-Ion Batteries in the Bolivian context
Balderrama, Sergio; Canedo, Walter; Lemort, Vincent ULg et al

in Proceedings of ECOS 2016 - the 29th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems (2016)

In Bolivia 44 % of the people living in rural areas do not have reliable access to electric energy. This is due to a combination of unfavourable geography and the lack of economic resources to achieve the ... [more ▼]

In Bolivia 44 % of the people living in rural areas do not have reliable access to electric energy. This is due to a combination of unfavourable geography and the lack of economic resources to achieve the necessary infrastructure. In this context, the main goal of this study is to evaluate the economic and technical feasibility of micro-grids including photovoltaic panels (PV), batteries systems and the possible inclusion of diesel generators for off-grid applications. To that aim, a linear optimization model was developed within the Pyomo framework in order to optimize both the installed capacities and dispatch of the PV, battery and diesel sub-systems. The defined objective function is the net present cost. The exogenous inputs of the optimization are the typical demand and solar irradiation of a region of Bolivia in order to achieve results close to real Bolivian systems. Results indicate that due to the high levels of subvention to hydrocarbons, the PV and Li-Ion technology are not yet competitive with a diesel generator for the electrification of rural areas. On the other hand a sensitivity analysis is performed and proves that if the government decide to stop part of the subvention or shared it between conventional and non-conventional sources, the PV becomes competitive and the Li-Ion batteries enter the market around 2020. [less ▲]

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See detailEconomic assessment of energy storage for load shifting in Positive Energy Building
Dumont, Olivier ULg; Carmo, carolina; Georges, Emeline ULg et al

Conference (2016)

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See detailEvaluation of simplified flexibility evaluation tools using a unit commitment model
Quoilin, Sylvain ULg; Nijs, Wouter; Hidalgo, Ignacio et al

in IEEE Digital Library (2015, December)

Different tools and methods have been proposed in the literature to assess the required flexibility resources and needs in a particular grid or geographical area. However, few of them are readily usable ... [more ▼]

Different tools and methods have been proposed in the literature to assess the required flexibility resources and needs in a particular grid or geographical area. However, few of them are readily usable in long term energy planning models because they require small time steps and detailed data. In this paper, two candidate methods to address the flexibility issues in such models are evaluated. A unit commitment model developed at the JRC, DispaSET 2.0, is used as a test case for the different simplified flexibility assessment tools. The modelled geographical area is Belgium, using historical data for the demand and VRE curves and their day-ahead forecast. Different VRE penetration scenarios are simulated to evaluate the flexibility of the power system. The simplified assessment tools are then run with the same inputs. Results indicate significant discrepancies between the detailed Unit Commitment model and the simplified tools. The underlying reasons are described and suggestions are formulated to improve their accuracy. [less ▲]

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See detailDynamic modeling and control strategies analysis of a novel small CSP biomass plant for cogeneration applications in building
Desideri, Adriano ULg; Amicabile, Simone; Alberti, Fabrizio et al

in Dynamic modeling and control strategies analysis of a novel small CSP biomass plant for cogeneration applications in building (2015, November 12)

A concentrated solar power (CSP) biomass combined heat and power (CHP) system based on organic Rankine cycle (ORC) technology developed in the framework of the EU founded BRICKER project is presented. The ... [more ▼]

A concentrated solar power (CSP) biomass combined heat and power (CHP) system based on organic Rankine cycle (ORC) technology developed in the framework of the EU founded BRICKER project is presented. The CHP system coupled with heat recovery ventilation technology and novel insulation material has the aim of reducing the energy consumption of existing building by up to 50%. A simplified approach to implement a dynamic model of the CHP system is proposed. The model is firstly used to investigate the performances of the CHP system control logic under extreme working condition. Secondly, the effectiveness in ensuring safe working conditions and in maximizing the sun power usage of two different solar field control approaches is investigated simulating the developed model over a reference day [less ▲]

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