References of "Lemort, Vincent"
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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 detailEXPERIMENTAL INVESTIGATIONS OF THE VALORIZATION OF THE EXHAUST WASTE HEAT OF A GASOLINE ENGINE BASED ON A RANKINE CYCLE
Dumont, Olivier ULg; Legros, Arnaud; Diny, Mouad et al

Conference (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 detailExperimental study of an oil-free steam piston expander for micro-combined heat and power systems
Bouvier, Jean-Louis; Lemort, Vincent ULg; Michaux, Ghislain et al

in Applied Energy (2016), 1 69

This paper presents an experimental study conducted on an oil-free steam piston expander for micro combined heat and power systems. This expander can produce electrical power (between 740 and 2400 W) with ... [more ▼]

This paper presents an experimental study conducted on an oil-free steam piston expander for micro combined heat and power systems. This expander can produce electrical power (between 740 and 2400 W) with a significant range of supply temperature (between 260 and 340 C) and pressure (between 20 and 34 bar). The expander electrical power output exhibits a fast dynamic response to a change of working or supply fluid conditions. The reached expander overall isentropic efficiency (including electrical generator efficiency) was between 19% and 40%. An empirical model has been developed in order to conduct a sensitivity analysis of the system by varying working variables such as supply and exhaust pressures, rotational speed and supply temperature. The parameters of this model have been identified using experimental results. The sensitivity analysis showed a limited increase of the electrical power output with a rotational speed until 900 rpm and a reduction of the power output for values beyond 900 rpm. It also highlighted the significant positive impact of the supply pressure on the electrical power output and the negative impact of the superheating on the expander overall isentropic efficiency. The obtained results are useful for the future control of the expander integrated into a Rankine cycle. Since the fluid at the expander exhaust is steam at a pressure close to 1 bar, it is possible to produce heat at a temperature close to 80 C, which is sufficient for most domestic applications (heating or direct hot water production). [less ▲]

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See detailVariable thickness scroll compressor performance analysis—Part II: Dynamic modeling and model validation
Bin, Peng; Lemort, Vincent ULg; Legros, Arnaud et al

in Proc IMechE Part E: J Process Mechanical Engineering (2016)

In order to investigate the performance of variable thickness scroll compressor, a detail mathematical modeling based on energy and mass balances is established in this two-part. In part II, dynamic ... [more ▼]

In order to investigate the performance of variable thickness scroll compressor, a detail mathematical modeling based on energy and mass balances is established in this two-part. In part II, dynamic modeling and model validation are developed. Temperature, pressure, mass flow of working chambers, friction loss power of moving parts, efficiency, and shaft power are investigated by solving the mathematical modeling. The experimental rig for variable thickness scroll compressor based on involute of circle, high order curve and arc is set up. From the comparison of the simulated and measured data, it can be seen that the compressor model predicts the mass flow, discharge temperature, and shaft power very well. So the proposed mathematical modeling can accurately describe all the suction, compression, and discharge processes for variable thickness scroll compressor. [less ▲]

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See detailVariable thickness scroll compressor performance analysis—Part I: Geometric and thermodynamic modeling
Bin, Peng; Lemort, Vincent ULg; Legros, Arnaud et al

in Proc IMechE Part E: J Process Mechanical Engineering (2016)

In order to investigate the performance of variable thickness scroll compressors, a detail mathematical modeling based on energy and mass balances is established in this two-part. In part I, the geometric ... [more ▼]

In order to investigate the performance of variable thickness scroll compressors, a detail mathematical modeling based on energy and mass balances is established in this two-part. In part I, the geometric modeling and thermodynamic modeling are developed. The profile based on circle involute, high order curve, and arc is built up using the base line method. The volume of working chambers from suction to discharge is defined. Thereafter, the evolution and derivative of the working chamber volume with respect to the orbiting angle are discussed. The energy and the mass balance for working chamber are described. Suction gas heating, radial and flank leakage, heat transfer between the working fluid, scroll wraps and plates are considered in the thermodynamic modeling. The established geometric modeling and thermodynamic modeling can provide better understanding of the variable thickness scroll compressor working process. The dynamical modeling and model validation are reported in part II. [less ▲]

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See detailRecent Advances on the Oil-Free Scroll Compressor
Bin, Peng; Legros, Arnaud; Lemort, Vincent ULg et al

in Recent Patents on Mechanical Engineering (2016), 9

Traditionally, scroll compressors are mainly made of metallic parts and oil is used to lubricate the friction surfaces and reduce discharge temperature and leakage. But for the food processing, medical ... [more ▼]

Traditionally, scroll compressors are mainly made of metallic parts and oil is used to lubricate the friction surfaces and reduce discharge temperature and leakage. But for the food processing, medical systems, textile manufacturing, fuel cell system, and other super-clean fields, the oil-less operation is critical. The oil is strictly forbidden in the working chambers of the scroll compressor in order to get the oil-free compressed air. So it is very important to develop the oil-free scroll compressor (OFSC). In this paper, the working principle and structure characteristics of the OFSC are investigated. Some of research works and the recent patents in this area are described and analyzed in detail, especially the water injection and air cooling OFSC. The future development on an OFSC is also presented. The analysis results demonstrated that there is dramatic growth potential in OFSC field. [less ▲]

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See detailNoWaste: waste heat re-use for greener truck
Bettoja, Federica; Perosino, Andrea; Lemort, Vincent ULg et al

in Proceedings of 6th Transport Research Arena (2016)

The present paper summarizes the key points of the European NoWaste Project, which aims at developing Rankine cycle systems for integration into long-haul trucks with the aim to convert the waste heat of ... [more ▼]

The present paper summarizes the key points of the European NoWaste Project, which aims at developing Rankine cycle systems for integration into long-haul trucks with the aim to convert the waste heat of the exhaust gases into useful energy usable in mechanical or electrical form. The first part of the paper describes the ORC system architectures defined for two different truck engines: one with EGR and the other one without EGR. For both engines, different cycle configurations and working fluids are compared in terms of energy performance and technical constraints. For both ORC systems, the paper shows the final technical choices made in terms of main components: boiler, condenser, expander and pump. The second part of the paper presents preliminary experimental results carried out on demonstrators of the two ORC systems. The objectives of these tests were to check the performance announced by the components’ manufacturers. Finally, the last part of the paper compares the cost of both systems. [less ▲]

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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 detailTransient performance evaluation of waste heat recovery Rankine cycle based system for heavy duty trucks
Grelet, Vincent; Reiche, Thomas; Lemort, Vincent ULg et al

in Applied Energy (2016)

The study presented in this paper aims to evaluate the transient performance of a waste heat recovery Rankine cycle based system for a heavy duty truck and compare it to steady state evaluation. Assuming ... [more ▼]

The study presented in this paper aims to evaluate the transient performance of a waste heat recovery Rankine cycle based system for a heavy duty truck and compare it to steady state evaluation. Assuming some conditions to hold, simple thermodynamic simulations are carried out for the comparison of several fluids. Then a detailed rst principle based model is also presented. Last part is focused on the Rankine cycle arrangement choice by means of model based evaluation of fuel economy for each concept where the fuels savings are computed using two methodologies. Fluid choice and concept optimization are conducted taking into account integration constraints (heat rejection, packaging . . . ). This paper shows the importance of the modeling phase when designing WHRS and yields a better understanding when it comes to a vehicle integration of a Rankine cycle in a truck. [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 detailOrganic Rankine cycles systems for waste heat recovery in marine applications
Bellolio Domke, Sebastian Andres ULg; Lemort, Vincent ULg; Rigo, Philippe ULg

Scientific conference (2015, November 26)

In marine applications powered by internal combustion engines, a considerable amount of the energy contained in fuel is wasted through thermal losses. Additionally, as the years go by, new and more severe ... [more ▼]

In marine applications powered by internal combustion engines, a considerable amount of the energy contained in fuel is wasted through thermal losses. Additionally, as the years go by, new and more severe standards and regulations are imposed to the maritime industry. Despite of the traditional use of the waste heat recovery systems in ships, in order to meet new emissions demands, the research towards less traditional ways to reduce vessels emissions has been pushed. Nowadays the use of Organic Rankine cycles (ORC) seems to be a very promising solution to increase the global efficiency in maritime applications by converting the vessel’s thermal losses into useful work. Even if ORC’s have been studied during the last decades, it is only in the recent years that the maritime industry has drawn its attention towards these systems. In the first part of this paper, a state of the art of ORC in marine applications is performed. Then, the use of an ORC over traditional waste heat recovery methods (steam Rankine cycles) used in ships is discussed. Finally, a thermodynamic steady-state model of an ORC is coupled to a vessel ICE to estimate the improvements in energy efficiency that could be achieved by implementing an ORC in a vessel. [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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See detailGlobal optimization of the production and the distribution system for typical European HVAC systems
Randaxhe, François ULg; Lemort, Vincent ULg; Lebrun, Jean ULg

in Energy Procedia (2015), 78

European countries have agreed on a new 2030 Framework with a 30% improvement in energy efficiency compared to projection and a 40% cut in greenhouse gas emissions compared to 1990 levels. With an ... [more ▼]

European countries have agreed on a new 2030 Framework with a 30% improvement in energy efficiency compared to projection and a 40% cut in greenhouse gas emissions compared to 1990 levels. With an estimated 11% of all the electrical energy used in Europe consumed by HVAC systems, the improvement of their efficiency is a key element to reach these targets. When looking at the energy flow in typical European HVAC systems, one can observe important degradation in efficiency associated to heating and cooling energy transportation systems together with a non-optimal use of the production plant. These inefficiencies are direct consequences of the system design with, quite often, a lack of consideration of the system part load or its off-design operation. This research attempts to identify the sensitivity of both cooling and heating HVAC systems to these conditions and to propose an approach to optimize the design and the operation of HVAC systems integrated in buildings considering trade-off between primary systems efficiency, distribution losses and auxiliaries consumption. [less ▲]

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See detailImpact of model reduction on the dynamic simulation of a micro-scale concentrated solar power system integrated with a thermal storage
Dickes, Rémi ULg; Wéber, Noé ULg; Lemort, Vincent ULg et al

in Proceedings of the ISES Solar World Congress 2015 (2015, November)

Because of the intermittent nature of solar irradiances, micro-scale solar thermal power systems almost never operate in nominal operating conditions. They are characterized by strong transients and ... [more ▼]

Because of the intermittent nature of solar irradiances, micro-scale solar thermal power systems almost never operate in nominal operating conditions. They are characterized by strong transients and require robust, fast and accurate dynamic simulation tools to permit a proper evaluation of their performance. Model reduction, i.e. the simplification of detailed models, is an attractive method to improve the computational efficiency while simulating such systems. In this context, a µCSP plant featuring a solar field of parabolic troughs, a thermocline storage and a 5kWe power unit is investigated. Both the solar field and the thermocline storage are modeled with complex and simplified methods. The whole power plant is simulated under identical operating condition and deviations between the simulation results are analyzed. Benefits and limitations of the current modeling approach are assessed. Improvements for the modeling of the thermocline storage are identified, implemented and validated. The Modelica language is used as simulation tool and the models developed in this work are integrated in the open-source ThermoCycle library. [less ▲]

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See detailTOWARDS THE OPTIMAL OPERATION OF AN ORGANIC RANKINE CYCLE UNIT BY MEANS OF MODEL PREDICTIVE CONTROL Andres
Hernandez Naranjo, Jairo Andres ULg; Desideri, Adriano ULg; Ionescu, Clara et al

in TOWARDS THE OPTIMAL OPERATION OF AN ORGANIC RANKINE CYCLE UNIT BY MEANS OF MODEL PREDICTIVE CONTROL (2015, October 14)

In this paper the optimal operation of an Organic Rankine Cycle (ORC) unit is investigated both in terms of energy production and safety conditions. Simulations on a validated dynamic model of a real re ... [more ▼]

In this paper the optimal operation of an Organic Rankine Cycle (ORC) unit is investigated both in terms of energy production and safety conditions. Simulations on a validated dynamic model of a real re- generative ORC unit, are used to illustrate the existence of an optimal evaporating temperature which maximizes energy production for some given heat source conditions. This idea is further extended using a perturbation based Extremum Seeking (ES) algorithm to find online the optimal evaporating tempera- ture. 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 of state estimators, making of it a suitable tool for industrial applica- tions. 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 ▲]

Detailed reference viewed: 30 (2 ULg)