References of "Lemort, Vincent"
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See detailThe use of semi-empirical modeling to extrapolate chiller performance maps
Lemort, Vincent ULg; Bertagnolio, Stéphane ULg

Conference (2010, June 28)

HVAC&R components operate most of the time in part load conditions for which little data are available from manufacturers. This makes performance prediction difficult. Approaches and problems are ... [more ▼]

HVAC&R components operate most of the time in part load conditions for which little data are available from manufacturers. This makes performance prediction difficult. Approaches and problems are presented for simulating the performance of HVAC&R components under part load conditions and under consideration of dynamic effects such as cycling. The seminar motivates a discussion about HVAC&R component modeling for part load and dynamic conditions and it dscusses what additional data are required from manufacturers to assess the performance at these conditions. [less ▲]

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See detailSimulation of a building and its HVAC system with an equation solver: Application to audit
Bertagnolio, Stéphane ULg; Andre, Philippe ULg; Lemort, Vincent ULg

in Building Simulationa: An international Journal (2010), 3(2), 139-152

A series of building energy simulation tools are being developed to help the building energy auditor in establishing his diagnosis (including benchmarking and detailed analysis of actual energy ... [more ▼]

A series of building energy simulation tools are being developed to help the building energy auditor in establishing his diagnosis (including benchmarking and detailed analysis of actual energy consumption) and in evaluating the selected Energy Conservation Measures (ECMs). A first simulation tool, dedicated to benchmarking, has been presented in a previous paper. The present paper focuses on the second simulation tool, dedicated to inspection and evaluation of ECMs. This Building-HVAC System global model includes simplified models of building zones and of HVAC equipment. Only a limited number of easily identifiable parameters are required. The simplicity of the models and the use of an equation solver to run the simulation ensure good robustness and full transparency. The development, the implementation and the application of these models are discussed. Focus is also given to the calibration of the tools to monthly utility bills. [less ▲]

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See detailEconomic Optimization of Small Scale Organic Rankine Cycles
Tchanche, Bertrand; Quoilin, Sylvain ULg; Declaye, Sébastien ULg et al

(2010, June)

The present paper focuses on the economic optimization of a small scale ORC in waste heat recovery application with specific investment cost as objective function. First, a pre-design model of the ORC was ... [more ▼]

The present paper focuses on the economic optimization of a small scale ORC in waste heat recovery application with specific investment cost as objective function. First, a pre-design model of the ORC was built and simulations run with different working fluids to evaluate their technical performance. In a second step, components and system cost models were built and simulations carried out to evaluate the cost effectiveness of systems associated with different fluids. The working fluids considered are R245fa, R123, R113, n-Pentane and n-Butane. Results indicate that for the same fluid, the point of high performance and that f cost-effectiveness do not match. The operating point for maximum power doesn’t correspond to that of the minimum specific investment cost. For n-Pentane, the maximum net power of 1.98 kW is obtained for an evaporator pressure of 5.14 bar and the specific investment cost is 5450 €/kW. For this same fluid, a minimum specific investment cost of 4440 €/kW is obtained for an evaporator pressure of 8.5 bar and the corresponding power output is 1.745 kW. The mismatch aforementioned is due to the thermodynamic properties such as liquid/vapour densities, which significantly influence system performance and components sizes. Seeking for profitable environmental solutions, economic optimization as a necessary step in the optimization of any thermodynamic system is highly advised. [less ▲]

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See detailComparative validation of three water cooling coil models
Gendebien, Samuel ULg; Bertagnolio, Stéphane ULg; Lemort, Vincent ULg

in Proceedings of the 10th REHVA World Congress - Clima 2010 (2010, May)

Water cooling coils are widely used in common HVAC systems. Accurate and robust cooling coil simulation models are required to perform reliable calculations of building cooling needs. Many different ... [more ▼]

Water cooling coils are widely used in common HVAC systems. Accurate and robust cooling coil simulation models are required to perform reliable calculations of building cooling needs. Many different cooling coil simulation models were developed during the last decades. The most commonly used cooling coil models are presented and compared in terms of implementation in the first part of the paper. A simplified variable boundary model is presented and comparatively and empirically validated to two reference models. [less ▲]

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See detailEvaluation du potentiel de récupération d’énergie à l’échappement d’un moteur TDI à l’aide d’un cycle de Rankine organique (ORC)
Declaye, Sébastien ULg; Quoilin, Sylvain ULg; Lemort, Vincent ULg

Poster (2010, May)

Une étude expérimentale a été menée sur un cycle de Rankine organique de faible puissance (2,5kW). Les résultats expérimentaux ont permis de calibrer un modèle du cycle qui a ensuite été utilisé afin ... [more ▼]

Une étude expérimentale a été menée sur un cycle de Rankine organique de faible puissance (2,5kW). Les résultats expérimentaux ont permis de calibrer un modèle du cycle qui a ensuite été utilisé afin d’évaluer le potentiel de récupération d’énergie à l’échappement d’un moteur TDI pour 13 points de fonctionnement représentatifs. Les résultats montrent la possibilité de produire jusqu’à 2,4kW de puissance mécanique additionnelle. La fraction d’énergie récupérée (ERR) pouvant atteindre 6,8% de la puissance à l’arbre moteur. [less ▲]

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See detailRankine cycle for waste heat recovery on commercial trucks: approach, constraints and modelling
Espinosa, Nicolas; Tilman, Loic; Lemort, Vincent ULg et al

(2010, May)

With increasing oil price and growing interest in cutting green house gases emissions, waste heat recovery techniques appear as a very promising path to enhance engine thermal efficiency ... [more ▼]

With increasing oil price and growing interest in cutting green house gases emissions, waste heat recovery techniques appear as a very promising path to enhance engine thermal efficiency. Thermoelectricity and Rankine cycles are two possible ways to recover thermal energy. The Rankine cycle shows the highest potential due to its higher cycle efficiency in comparison with the current state-of-the-art thermoelectric materials intrinsic conversion ratio. This paper will focus on the Rankine cycle system. The first part of the paper lists and describes the constraints of a heat recovery Rankine cycle system associated to a long haulage truck: limitation of heat available in the heat source, vehicle heat rejection constraints, safety and environmental issues for the working fluid, and backpressures occurring during the heat recovery process. The second part of the paper presents a 0-D simulation model of a Rankine cycle system. It is shown how the model can be used to compare the performance achieved with several working fluids. Moreover, basic thermodynamic limitations of the system are underlined. Conclusions are drawn concerning the limitation of using only thermodynamic simulations. The performance of the condenser (and its influence on the overall performance) has been investigated more in details, which is shown in the third part of the paper. This was carried out based on a 1-D simulation model of the condenser. Influence of the condenser size and ram air effect are discussed, and the impact on the Rankine cycle is assessed. [less ▲]

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See detailExperimental study and modeling of an Organic Rankine Cycle using scroll expander
Quoilin, Sylvain ULg; Lemort, Vincent ULg; Lebrun, Jean ULg

in Applied Energy (2010), 87(4), 1260-1268

This paper presents both a numerical model of an Organic Rankine Cycle (ORC) and an experimental study carried out on a prototype working with refrigerant HCFC-123, and whose heat sources consist in two ... [more ▼]

This paper presents both a numerical model of an Organic Rankine Cycle (ORC) and an experimental study carried out on a prototype working with refrigerant HCFC-123, and whose heat sources consist in two hot air flows. The ORC model is built by interconnecting different sub-models: the heat exchanger models, a volumetric pump model and a scroll expander model. Measured performance of the ORC prototype is presented and used to validate the ORC model. This model is finally used to investigate potential improvements of the prototype. [less ▲]

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See detailRadiant ceiling systems coupled to its environment part 1: Experimental analysis
Fonseca, Néstor; Cuevas, Cristian; Lemort, Vincent ULg

in Applied Thermal Engineering (2010), 30

This paper presents the results of an experimental analysis of the radiant ceiling systems in both heating and cooling modes coupled to its environment (fenestration, walls, internal loads and ventilation ... [more ▼]

This paper presents the results of an experimental analysis of the radiant ceiling systems in both heating and cooling modes coupled to its environment (fenestration, walls, internal loads and ventilation system). The main objective of this study is to present the results of the experimental analysis and measurement methods and its discussion. Two test chambers are adapted in a way to reproduce as good as possible the characteristics of the real offices located in Brussels (Belgium). Forty-six tests are performed to observe the influence of parameters such as the mass flow rate, supply water temperature, fenestration and ventilation system effects and thermal load distribution. Laboratory test results show that the influence of surfaces temperatures inside the room, especially the facade, is considerable. Therefore, the system must be evaluated together with its designed environment and not as separate HVAC equipment. [less ▲]

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See detailCharacterization of a scroll compressor under extended operating conditions
Cuevas, Cristian; Lebrun, Jean ULg; Lemort, Vincent ULg et al

in Applied Thermal Engineering (2010), 30

Refrigeration and air-conditioning compressors are designed to work under well-defined conditions. In some applications it is interesting to observe their performances beyond these conditions, for example ... [more ▼]

Refrigeration and air-conditioning compressors are designed to work under well-defined conditions. In some applications it is interesting to observe their performances beyond these conditions, for example in the case of a high temperature two-stage heat pump or of a cooling system working at high temperature. In this study a compressor is characterized experimentally with refrigerant R134a and through 118 tests at condensing pressures varying from 8.6 up to 40.4 bar (tsat = 33.9°C to tsat = 100.8°C) and evaporating pressures varying from 1.6 up to 17.8 bar (tsat = -15.6°C to tsat = 62.4°C). Under these conditions the compressor motor was pushed at its maximal current in several tests. This compressor’s performance is mainly characterized by its isentropic and volumetric efficiencies. It presents a maximal isentropic efficiency of 72%, corresponding to a pressure ratio of around 2.5–2.6. The volumetric efficiency decreases linearly from almost 1.0 (for a pressure ratio of 1.3) to 0.83 (for a pressure ratio of 9.7). A slight degradation of the isentropic and volumetric efficiencies is observed when the compressor supply and exhaust pressures are increased for a given pressure ratio; this could be due to an internal leakage. The compressor tests are used to identify the six parameters of a semi-empirical simulation model. After parameter identification, experimental and simulated results are in very good agreement, except for some points at high compressor power where the compressor is pushed at its maximal current. [less ▲]

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See detailExperimental investigation on a hermetic scroll expander
Lemort, Vincent ULg; Quoilin, Sylvain ULg; Pire, Christophe

in Proceedings of the 7th International IIR Conference on Compressors (2009, September)

This paper presents the results of an experimental study carried out on a prototype of hermetic scroll expander, integrated into a gas cycle test rig, whose working fluid is R245fa. This system was ... [more ▼]

This paper presents the results of an experimental study carried out on a prototype of hermetic scroll expander, integrated into a gas cycle test rig, whose working fluid is R245fa. This system was designed to test only the performance of the expander. It is mainly made up of a scroll compressor, a scroll expander, a heat exchanger and a by-pass valve. The latter is used to adjust the pressure ratio imposed to the expander. The expander is originally a compressor used for heat pump applications and characterized by a nominal power input of 2.5 kW. Performance of the expander is evaluated in terms of isentropic effectiveness and filling factor as function of the main operating conditions. The study also investigates the impact of oil mass fraction on the expander performance. Using the experimental data, parameters of a simulation model of the expander are identified. The model is finally used to analyze the measured performance of the expander. [less ▲]

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See detailTesting and validation of simulation tools of HVAC mechanical equipment including their control strategies. Part III: Validation of an air-cooled chiller model
Lemort, Vincent ULg; Lebrun, Jean ULg; Felsmann, Clemens

(2009, July)

This paper presents a semi-empirical steady-state model of an air-cooled water chiller. The first part of the paper shows how the model is built by associating a scroll compressor and two heat exchanger ... [more ▼]

This paper presents a semi-empirical steady-state model of an air-cooled water chiller. The first part of the paper shows how the model is built by associating a scroll compressor and two heat exchanger sub-models. The second part of the paper presents the parameters identification process based on published manufacturer data (for the compressor and the whole chiller models). The only encountered difficulty is the characterization of the fan control model, since information is lacking to identify its parameters. The third part of the paper presents results of an experimental investigation carried out on the same chiller integrated into an existing cooling plant. A detailed analysis of the experimental data allowed a better understanding of the chiller’s operation and a better identification of the model’s parameters (such as the models of the fan control and of the compressor staging control). Moreover, a simple but realistic model of the condenser hot gas by-pass was introduced. As a result, deviations between predictions by the model and the experimental data were considerably reduced. The model is finally found to predict the total cooling energy and the total electrical consumption over a long-term simulation period with a very good accuracy. [less ▲]

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See detailTesting and validation of simulation tools of HVAC mechanical equipment including their control strategies. Part II: Validation of cooling and heating coil models
Felsmann, Clemens; Lebrun, Jean ULg; Lemort, Vincent ULg et al

(2009, July)

This paper presents detailed information about testing and validation of cooling and heating coil models. The work has been carried out under Subtask D of the International Energy Agency’s SHC Task 34 ... [more ▼]

This paper presents detailed information about testing and validation of cooling and heating coil models. The work has been carried out under Subtask D of the International Energy Agency’s SHC Task 34/ECBCS Annex 43 (Testing and Validation of Building Energy Simulation Tools). The goal of this Subtask (Mechanical Equipment and Control Strategies) was to develop and test methods that would help evaluating, diagnosing and correcting HVAC mechanical equipment simulation software. [less ▲]

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See detailTesting and validation of simulation tools of HVAC mechanical equipment including their control strategies. Part I: Description of the validation test cases
Felsmann, Clemens; Lebrun, Jean ULg; Lemort, Vincent ULg et al

(2009, July)

This paper presents the work carried out under Subtask D of the International Energy Agency SHC Task 34/ECBCS Annex 43 (Testing and Validation of Building Energy Simulation Tools). The goal of this ... [more ▼]

This paper presents the work carried out under Subtask D of the International Energy Agency SHC Task 34/ECBCS Annex 43 (Testing and Validation of Building Energy Simulation Tools). The goal of this Subtask (Mechanical Equipment and Control Strategies) was to develop methods to help evaluating, diagnosing and correcting HVAC mechanical equipment simulation software. [less ▲]

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See detailDevelopment and validation of a condenser three zones model
Cuevas, Cristian; Lebrun, Jean ULg; Lemort, Vincent ULg et al

in Applied Thermal Engineering (2009)

A general and simple ‘‘deterministic” model of a refrigeration condenser is presented. The model assumes that the condenser can be divided into three distinct zones on the refrigerant side: the vapour de ... [more ▼]

A general and simple ‘‘deterministic” model of a refrigeration condenser is presented. The model assumes that the condenser can be divided into three distinct zones on the refrigerant side: the vapour de-superheating zone, the two-phase zone and the sub-cooled liquid zone. The model inputs are the air supply temperature, the air mass flow rate, the refrigerant supply temperature (or the over-heating), the exhaust sub-cooling and the refrigerant mass flow rate. The model is able to identify the pressures and temperatures in each zone and the corresponding heat flows. The model also gives the geometrical repartition among the zones and the pressure drop on air-side. The condenser model is validated with a total of 183 tests. Testing conditions cover a very wide domain, including pressures up to 40 bars with refrigerant R134a. The model is able to predict with a probability of 95% the condenser supply pressure within a confidence interval of +0.5 and 0.1 bar. This means a condenser power confidence interval within 200 and +100 W, which is considered here as acceptable. Refrigerant pressure drop is predicted with a higher error, but it is attributed to measuring uncertainty. On the other hand, air pressure drop is predicted with a very poor accuracy. Undoubtedly, this is due to the friction factor correlation used in this study which is not the most adequate. Here a difference of 40% is obtained. [less ▲]

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See detailEvaluation, correction et validation de modèles de composants d'une centrale de production d'eau glacée
Lemort, Vincent ULg; Lebrun, Jean ULg

(2009, May)

Ce papier présente des outils d’évaluation, de correction et de validation des modèles de simulation d’un groupe frigorifique et d’une batterie froide. Après avoir brièvement décrit les modèles, le papier ... [more ▼]

Ce papier présente des outils d’évaluation, de correction et de validation des modèles de simulation d’un groupe frigorifique et d’une batterie froide. Après avoir brièvement décrit les modèles, le papier montre comment leurs paramètres peuvent être identifiés sur base uniquement des performances publiées par les constructeurs. Cette information est incomplète et des hypothèses rationnelles sont proposées. Les modèles sont validés par comparaison des résultats de simulations avec à ceux obtenus au moyen d’autres modèles et/ou avec des données expérimentales. Ces comparaisons conduisent finalement à encore améliorer les modèles et à en ré-ajuster les paramètres. [less ▲]

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See detailTechnological and Economical Survey of Organic Rankine Cycle Systems
Quoilin, Sylvain ULg; Lemort, Vincent ULg

(2009, April)

This paper presents an overview of current R&D in the field of small and middle scale Organic Rankine Cycles (ORC’s). Major ORC’s applications are described and their technical and economical maturity is ... [more ▼]

This paper presents an overview of current R&D in the field of small and middle scale Organic Rankine Cycles (ORC’s). Major ORC’s applications are described and their technical and economical maturity is analyzed. The paper also emphasizes the selection criteria for the expander and for the working fluid. [less ▲]

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See detailTests on a vapor injection scroll compressor
Lemort, Vincent ULg; Quoilin, Sylvain ULg

Report (2009)

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See detailDesigning scroll expanders for use in heat recovery Rankine cycles
Lemort, Vincent ULg; Quoilin, Sylvain ULg

(2009)

This paper first investigates experimentally the performance of a prototype of oilfree open-drive scroll expander working with water and with HCFC-123. Using experimental data, two different simulation ... [more ▼]

This paper first investigates experimentally the performance of a prototype of oilfree open-drive scroll expander working with water and with HCFC-123. Using experimental data, two different simulation models of the expander are then proposed and validated. These models are finally used to analyze the measured performance with regard to the expander design characteristics. [less ▲]

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See detailTesting and modeling a scroll expander integrated into an Organic Rankine Cycle
Lemort, Vincent ULg; Quoilin, Sylvain ULg; Cuevas, Cristian et al

in Applied Thermal Engineering (2009), 29

Organic Rankine Cycles (ORC’s) are particularly suitable for recovering energy from low-grade heat sources. This paper first presents the results of an experimental study carried out on a prototype of an ... [more ▼]

Organic Rankine Cycles (ORC’s) are particularly suitable for recovering energy from low-grade heat sources. This paper first presents the results of an experimental study carried out on a prototype of an open-drive oil-free scroll expander integrated into an ORC working with refrigerant HCFC-123. By exploiting the overall expander performance measurements, the eight parameters of a scroll expander semi-empirical model are then identified. The model is able to compute variables of first importance such as the mass flow rate, the delivered shaft power and the discharge temperature, and secondary variables such as the supply heating-up, the exhaust cooling-down, the ambient losses, the internal leakage and the mechanical losses. The maximum deviation between the predictions by the model and the measurements is 2% for the mass flow rate, 5% for the shaft power and 3 K for the discharge temperature. The validated model of the expander is finally used to quantify the different losses and to indicate how the design of the expander might be altered to achieve better performances. This analysis pointed out that the internal leakages and, to a lesser extent, the supply pressure drop and the mechanical losses are the main losses affecting the performance of the expander. [less ▲]

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See detailContribution to the Characterization of Scroll Machines in Compressor and Expander Modes
Lemort, Vincent ULg

Doctoral thesis (2008)

This thesis contributes to the knowledge and the characterization of scroll machines and their systems. It is based on experimental and modeling works carried out on: a) A hermetic scroll compressor used ... [more ▼]

This thesis contributes to the knowledge and the characterization of scroll machines and their systems. It is based on experimental and modeling works carried out on: a) A hermetic scroll compressor used inside an air-cooled water chiller. b) An oil-free open-drive scroll expander integrated into an Organic Rankine Cycle (ORC) power system. c) Open-drive scroll compressor and expander used in a Liquid Flooded Ericsson Cycle Cooler (LFEC). Such a system uses the liquid flooding of the compressor and of the expander to approach isothermal compression and expansion processes. New semi-empirical models of the scroll compressor and expander were proposed and existing models improved. A deterministic model of the scroll expander was established. The model associates a geometrical description of the machine with a thermodynamic description of the expansion process. This model was validated for the two expanders investigated experimentally. The model validation revealed that the performance of the expanders is mainly affected by the supply pressure drop and by the internal leakages. Using the validated model, parametric studies were carried out to investigate the variation of the performance of both expanders with modification of their design and with the operating parameters. The thesis also investigated the scroll machines from the point of view of their integration into thermal systems. A first experimental investigation was carried out on an air-cooled chiller. The scroll compressor semi-empirical model, with its parameters identified on the basis of published manufacturer data, was used as a refrigerant flow meter. The analysis of the experimental data allowed a better understanding of the chiller operation and a better identification of its model parameters (such as the fan and the hot gas bypass control models). A second experimental investigation was carried out on an ORC power system, working with R123. In order to select the most appropriate fluid, the performances achieved with four different fluids were compared by simulation. The experimental study confirmed that the scroll expander is a good candidate for an ORC system: the tested prototype presented a good performance (the maximum global isentropic effectiveness achieved was 68%). Using an ORC simulation model, parametric studies were carried out to investigate the effects of the expander characteristics and operating conditions on the cycle performance. The latter is mainly affected by the expander internal leakage and by the liquid subcooling at the condenser exhaust. A third experimental investigation was performed on a LFEC working with nitrogen as refrigerant and alkyl-benzene oil as flooding liquid. Experimental data was used to identify the parameters of the scroll compressor and expander semi-empirical models. Parametric studies were performed to identify the different factors affecting their performance. One of the undesirable features of the machines is the increase of the supply and exhaust pressure drops with the increase of oil quantity. [less ▲]

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