References of "Lebrun, Jean"
     in
Bookmark and Share    
Full Text
See detailIEA Annex 48: Reversible Air-Conditioning
Andre, Philippe ULg; Lebrun, Jean ULg

Report (2011)

Rapport de synthèse du projet IEA Annex 48: Reversible Air-conditioning

Detailed reference viewed: 16 (3 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 324 (51 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 108 (9 ULg)
Full Text
Peer Reviewed
See detailDevelopment and use of equation based simulation tools to support audit of commercial buildings
Bertagnolio, Stéphane ULg; Lebrun, Jean ULg; Andre, Philippe ULg

in Proceedings of the eleventh International IBPSA Conference, Glasgow, UK (2009, July)

A series of new 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 ... [more ▼]

A series of new 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 Opportunities (ECOs). The Building-HVAC System global models presented here include simplified models of building zones and of HVAC equipment. Only a limited number of easily identifiable parameters is 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 use of these models are discussed in the present paper. Focus is also given to the calibration of the tools to the monthly utility bills. [less ▲]

Detailed reference viewed: 59 (18 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 44 (7 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 49 (2 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 37 (3 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 136 (18 ULg)
Full Text
Peer Reviewed
See detailDeveloppement et utilisation de modèles de simulation pour l'audit et la rénovation des bâtiments conditionnés
Bertagnolio, Stéphane ULg; Lebrun, Jean ULg; Andre, Philippe ULg

(2009, May)

Une suite d’outils de simulation de bâtiment et de système de climatisation destinés à assister l’audit et la rénovation des bâtiments commerciaux est actuellement en développement. Les outils en question ... [more ▼]

Une suite d’outils de simulation de bâtiment et de système de climatisation destinés à assister l’audit et la rénovation des bâtiments commerciaux est actuellement en développement. Les outils en question sont développés de façon à limiter le nombre de paramètres demandés à l’utilisateur et à garder une transparence totale pour ce dernier. Dans un premier temps, le développement des modèles et leur implémentation dans un solveur d’équations sont discutés. L’identification des paramètres des modèles développés est ensuite discutée et illustrée par un exemple d’application. [less ▲]

Detailed reference viewed: 107 (25 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 72 (5 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 388 (39 ULg)
Full Text
Peer Reviewed
See detailSimulation-assisted audit of an air conditioned building
Bertagnolio, Stéphane ULg; Lebrun, Jean ULg; Hannay, Cleide ULg et al

in Proceedings of the 8th International Conference for Enhanced Building Operation, Berlin, Germany (2008, October)

The example presented here concerns the audit of a typical, medium-size, office building erected in Brussels at the end of the sixties. This building is equipped with a classical old fashioned air ... [more ▼]

The example presented here concerns the audit of a typical, medium-size, office building erected in Brussels at the end of the sixties. This building is equipped with a classical old fashioned air conditioning system with air handling units and four-pipes induction units. In the first part of the paper, a classical audit procedure is applied. It consists in a systematic analysis of all information available, with help of very simple calculation. In the second part of the paper, an equation-based building-HVAC simulation tool is used to assist the audit. Fuel and electricity consumption are then interpreted and significant energy saving opportunities are identified. [less ▲]

Detailed reference viewed: 82 (18 ULg)
Full Text
See detailNew simulation tools usable in the energy audit of HVAC systems
Lebrun, Jean ULg; Bertagnolio, Stéphane ULg

Scientific conference (2008, October)

Detailed reference viewed: 49 (8 ULg)
Full Text
Peer Reviewed
See detailSimulation of a building and its HVAC system with an equation solver: Application to benchmarking
Bertagnolio, Stéphane ULg; Lebrun, Jean ULg

in Building Simulation: An International Journal (2008), 1(3), 234-250

The today - availability of powerful engineering equation solvers is opening very new possibilities in technical component modelling and in system simulation. The simulation models, the “user guide” and ... [more ▼]

The today - availability of powerful engineering equation solvers is opening very new possibilities in technical component modelling and in system simulation. The simulation models, the “user guide” and the “reference guide” are all included in a same file. Reliable “reference” and “simplified” models are currently available for the building zone and for most HVAC components. Focus is given here on “simplified” models and on a simulation tool, called “Benchmark”. This tool should help an auditor to make the best use of the limited information usually available about actual fuel and electricity consumptions and to get a very first evaluation of the actual performances of a given HVAC system. An example of such use is presented. Another simulation tools and more information about the modelling of HVAC components will be presented in a further paper. [less ▲]

Detailed reference viewed: 403 (38 ULg)
Full Text
Peer Reviewed
See detailBuilding and HVAC system simulation with the help of an engineering equation solver
Bertagnolio, Stéphane ULg; Masy, Gabrielle; Andre, Philippe ULg et al

in Proceedings of the 3rd National conference of the IBPSA-USA, Berkeley, CA (2008, July)

A simplified Building-HVAC system model is presented here. It includes simplified models of building zone and of HVAC equipment. The simplified building zone model is based on a R and C network, whose ... [more ▼]

A simplified Building-HVAC system model is presented here. It includes simplified models of building zone and of HVAC equipment. The simplified building zone model is based on a R and C network, whose parameters are adjusted trough a frequency characteristic analysis. The implementation of the classical phenomena taking place in building dynamics is discussed. The simplified building model is compared with more detailed models, using the BESTEST procedure. The application of the presented model to the audit of commercial buildings is also discussed. [less ▲]

Detailed reference viewed: 423 (17 ULg)
Full Text
See detailDevelopment of a simplified Building-HVAC System model with the help of an equation solver
Bertagnolio, Stéphane ULg; Lemort, Vincent ULg; Lebrun, Jean ULg

Conference (2008, June 25)

This seminar shows how modeling and simulation environments that are built using equation-based solvers can benefit the building energy community. Such modeling and simulation environments separate the ... [more ▼]

This seminar shows how modeling and simulation environments that are built using equation-based solvers can benefit the building energy community. Such modeling and simulation environments separate the formulation of a model’s underlying physics from its numerical solution algorithms. This allows input-output free modeling, it leads to faster model development time and it facilitates model reuse for different applications. Equation-based modeling and simulation environments are frequently used in various industrial sectors. For building energy simulation, however, they have not yet enjoyed wide-spread use. This seminar encourages discussions to understand their applicability, advantages and limitations for the building energy community. [less ▲]

Detailed reference viewed: 38 (6 ULg)
Full Text
Peer Reviewed
See detailHeat Pumping and Reversible Air Conditioning: How to make the best use of HVAC equipment ?
Bertagnolio, Stéphane ULg; Lebrun, Jean ULg; Andre, Philippe ULg et al

in Proceedings of the 9th International IEA Heat Pump Conference, Zurich, Switzerland (2008, May)

Detailed reference viewed: 70 (13 ULg)
Full Text
Peer Reviewed
See detailNumerical Simulation of a Scroll Expander for Use in a Rankine Cycle
Lemort, Vincent ULg; Quoilin, Sylvain ULg; Lebrun, Jean ULg

(2008)

This paper presents two simulation models of scroll expanders for use in heat recovery Rankine cycle applications: a detailed reference model and a simplified model. The reference model associates a ... [more ▼]

This paper presents two simulation models of scroll expanders for use in heat recovery Rankine cycle applications: a detailed reference model and a simplified model. The reference model associates a detailed geometrical description of the expander to a thermodynamic modeling of the expansion process in the machine. Due to large computational effort, the reference model is not appropriate for simulation of the entire Rankine cycle system. The paper shows how a simplified model can be built from the reference model. This model involves a limited number of parameters, which describe the main features of the machine. An experimental study is carried out on a prototype of Rankine cycle working with HCFC-123. Based on detailed measurements, the validation of both models is conducted. It is found that both models are able to predict the mass flow rate, the delivered shaft power and the discharge temperature with a good accuracy. [less ▲]

Detailed reference viewed: 734 (38 ULg)
Full Text
Peer Reviewed
See detailHeat pumping and reversible air conditioning : how to make the best use of HVAC equipment ?
Bertagnolio, Stéphane ULg; Lebrun, Jean ULg; Andre, Philippe ULg et al

Conference (2008)

Substituting a heat pump to a boiler may save more than 50% of primary energy, if electricity is produced by a modern combined cycle power plant (and even more if a part of that electricity is produced ... [more ▼]

Substituting a heat pump to a boiler may save more than 50% of primary energy, if electricity is produced by a modern combined cycle power plant (and even more if a part of that electricity is produced using renewable sources). Two of the most attractive heat pumps applications consist in recovering the heat rejected by the condenser of an existing chiller and in using this chiller in reversible mode. This is the topic of the IEA-ECBCS Annex 48 project (“Heat pumping and reversible air conditioning”). An overview of the project is presented and the work of the different participants is briefly explained. Case studies are also briefly presented and more details are given on one of them. [less ▲]

Detailed reference viewed: 53 (3 ULg)
Full Text
Peer Reviewed
See detailA contribution to the audit of an air-conditinioning system: modelling, simulation and benchmarking
Andre, Philippe ULg; Hannay, Cleide; Hannay, Jules et al

in Building Services Engineering Research & Technology (2008), 29(1), 85-98

This paper intends to show how benchmarks can help in the audit of a HVAC system and how these benchmarks can be generated. The work presented is part of the European ‘AUDITAC’ project. How can an auditor ... [more ▼]

This paper intends to show how benchmarks can help in the audit of a HVAC system and how these benchmarks can be generated. The work presented is part of the European ‘AUDITAC’ project. How can an auditor declare that a given HVAC is ‘consuming too much’? He can’t make any judgment, if not having some reference, i.e. some ‘benchmarks’ available. Focus is given here to cooling regime, but even then, heating cannot be forgotten (for example, the remaining heating demand can be satisfied thanks some recovery on the condensers of the chillers). The dramatic question is: what should be the consumption(s) for such a building, in such a climate, with such occupancy, such internal loads and such actual indoor environment? Better than to look for a (very hypothetical) global weather index, similar to heating degree-days, it seems more rational to run a simulation model on a few thousands of hours, corresponding to one (or to several) cooling season(s). Current performances of simulation tools make this approach very expedient. The climate can then be considered as it is, without any simplification. The main simplification is still welcome on the system (buildingþHVAC) side, in order to get calculation robustness, easy understanding and easy parameter identification. In this perspective, the building has to be subdivided in a very limited number of zones and only a few components of the HVAC system have to be included in the simulation model, with as simple as possible control strategies. [less ▲]

Detailed reference viewed: 61 (17 ULg)