References of "Lemort, Vincent"
     in
Bookmark and Share    
Peer Reviewed
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 ▲]

Detailed reference viewed: 420 (43 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 32 (6 ULg)
Full Text
Peer Reviewed
See detailDirect control service from residential heat pump aggregation with specified payback
Georges, Emeline ULg; Cornélusse, Bertrand ULg; Ernst, Damien ULg et al

in Proceedings of the 19th Power Systems Computation Conference (PSCC) (2016, June)

This paper addresses the problem of an aggregator controlling residential heat pumps to offer a direct control flexibility service. The service is defined by a 15 minute power modulation, upward or ... [more ▼]

This paper addresses the problem of an aggregator controlling residential heat pumps to offer a direct control flexibility service. The service is defined by a 15 minute power modulation, upward or downward, followed by a payback of one hour and 15 minutes. The service modulation is relative to an optimized baseline that minimizes the energy costs. The potential amount of modulable power and the payback effect are computed by solving mixed integer linear problems. Within these problems, the building thermal behavior is modeled by an equivalent thermal network made of resistances and lumped capacitances whose parameters are identified from validated models. Simulations are performed on 100 freestanding houses. For an average 4.3 kW heat pump, results show a potential of 1.2 kW upward modulation with a payback of 600 Wh and 150 Wh of overconsumption. A downward modulation of 500 W per house can be achieved with a payback of 420 Wh and 120 Wh of overconsumption. [less ▲]

Detailed reference viewed: 56 (14 ULg)
Full Text
Peer Reviewed
See detailDescription of a Modelica-based thermal building model integrating multi-zone airflows calculation
Ransy, Frédéric ULg; Gendebien, Samuel ULg; Lemort, Vincent ULg

Conference (2016, May 23)

Nowadays, in newly built housings, energy losses due to the ventilation can represent up to 50 % of the total building energy consumption. As a result, heat recovery ventilation units are widely used in ... [more ▼]

Nowadays, in newly built housings, energy losses due to the ventilation can represent up to 50 % of the total building energy consumption. As a result, heat recovery ventilation units are widely used in order to save primary energy and different control strategies for ventilation systems are investigated. For instance, demand control ventilation sounds like a promising solution to decrease the energy impact of the ventilation system in the residential sector. An accurate building model integrating the influence of ventilation (so called thermo-aeraulic building model) is necessary in order to investigate the control and the impact of the ventilation system on a yearly basis. The aim of the present paper consists in a description of a combined multi-zone airflow network model and thermal building model implemented in the Modelica language. The thermal model is a simplified dynamic model using equivalent thermal resistance and capacity. The airflow network is based on the traditional electrical circuit analogy. The model can be used for ventilation systems design, infiltration rate calculation, inside air quality calculation, energy consumption calculation, etc. The first part of the paper details the multi-zone thermal building model. The results obtained from the model are compared to experimental in situ results collected in the typical single family house test facilities. Those experimental results have been obtained in the frame of the IEA-EBC Annex 58. The second part of the paper introduces the multi-zone airflow network building model. Obtained model results are compared with the results provided by a typical multizone airflow analysis software, for a simple three zones test case. The third part of the paper describes the coupling between both thermal and airflow models. The different numerical problems encountered are described and solutions are discussed. [less ▲]

Detailed reference viewed: 25 (4 ULg)
Full Text
Peer Reviewed
See detailEnergy Reduction in Public Building Stock: Assessing the Impact of Control Strategy over Expected Energy Savings and Indoor Comfort Level
Ruiz Flores, Roberto ULg; D’Antoni, Matteo; Lemort, Vincent ULg

in CLIMA 2016 - proceedings of the 12th REHVA World Congress: volume 1. Aalborg: Aalborg University, Department of Civil Engineering. (2016, May)

In the framework of EU FP7 BRICKER project, the renovation of public owned nonresidential buildings is addressed through the installation of innovative passive and active technologies. The expected impact ... [more ▼]

In the framework of EU FP7 BRICKER project, the renovation of public owned nonresidential buildings is addressed through the installation of innovative passive and active technologies. The expected impact is a primary energy reduction of about 50% with respect to the existing scenario with a large replication potential under different European countries. In order to achieve such ambitious goal one issue that cannot be ignored is the effect of control strategy, not only over the resulting energy performance but also over the resulting indoor comfort conditions. In this paper, the actual control strategy implemented in the Belgian demo of Bricker project is introduced, compared against an ideal approach and accordingly optimized. The resulting proposed approach is then tested by means of numerical simulations over a base case scenario before renovation. The main conclusion of this work is the demonstration that control strategy of energy generation and distribution systems has to be revised whenever deep renovation of passive or active building technologies is undertaken. Contrarily to which, project renovation goals cannot be met. [less ▲]

Detailed reference viewed: 25 (7 ULg)
Full Text
Peer Reviewed
See detailPerformance of a radial-inflow turbine integrated in an ORC system and designed for a WHR on truck application: An experimental comparison between R245fa and R1233zd
Guillaume, Ludovic ULg; Legros, Arnaud ULg; Desideri, Adriano ULg et al

in Applied Energy (2016)

The goal of this study is to experimentally compare the performance of an Organic Rankine Cycle (ORC) system equipped with a radial-inflow turbine for two working fluids: R245fa and R1233zd. The radial ... [more ▼]

The goal of this study is to experimentally compare the performance of an Organic Rankine Cycle (ORC) system equipped with a radial-inflow turbine for two working fluids: R245fa and R1233zd. The radial- inflow turbine is a small-scale prototype designed to convert the waste heat from the exhaust gases of a truck combustion engine and was developed mainly using components of truck turbochargers. It is directly connected to a high-speed synchronous generator. The bearings system of the turbine and the generator have the innovative particularity to be respectively lubricated and cooled down by the working fluid so no additional lubricant or coolant is needed. The experimental comparison is carried out over a test-rig equipped with the radial turbine. The heat wasted by the truck through the exhaust gases is sim- ulated using an electric oil boiler coupled to the ORC loop. The electrical power supplied by the turbine, limited to a maximum of 3.5 kWel by the generator, is then dissipated in a load bank composed of truck fans while the condenser is cooled by a water loop. Measurements in steady-state are performed in order to evaluate the performance of the turbine-generator set when varying the pressure ratio, the rotational speed, the inlet temperature and the mass flow rate of the turbine and the lubrication flow rate of the bearings for various oil temperatures and mass flow rates. In order to identify the most suitable fluid for the Waste Heat Recovery (WHR) application, three comparison methods are proposed and discussed based on the measurements. Finally, because the turbine-generator set is the first oil-free prototype developed by the manufacturer, potential sources of improvements are discovered and discussed. [less ▲]

Detailed reference viewed: 20 (5 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 22 (4 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 25 (2 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 23 (4 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 21 (3 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 75 (6 ULg)
Peer Reviewed
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 ▲]

Detailed reference viewed: 41 (4 ULg)
Peer Reviewed
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)

Detailed reference viewed: 43 (5 ULg)
Full Text
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 ▲]

Detailed reference viewed: 59 (8 ULg)
Full Text
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 ▲]

Detailed reference viewed: 21 (1 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 28 (7 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 86 (13 ULg)