References of "Lebrun, Jean"
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See detailFrom model validation to production of reference simulations: how to increase reliability and applicability of building and HVAC simulation models
Andre, Philippe ULg; Georges, Bernard ULg; Lebrun, Jean ULg et al

in Building Services Engineering Research & Technology (2008), 29(1), 61-72

Validation of simulation models appears from a long time as a key issue in order to promote a more intensive and more efficient use of simulation models in the field of building and HVAC simulation. IEA ... [more ▼]

Validation of simulation models appears from a long time as a key issue in order to promote a more intensive and more efficient use of simulation models in the field of building and HVAC simulation. IEA Annex 34/43 originally targeted a number of specific applications where a more advanced validation was required: ground coupling problems, multizone building, shading, day lighting and cooling load interaction, HVAC components and ventilated facades. These validation exercises were built on the large methodological experience obtained in previous projects and address sometimes very fundamental problems of heat transfer in buildings. Consulting engineers and practitioners might see these exercises as a bit too far from their objectives and it is the reason why an additional activity was proposed with the specific aim of producing, based upon the results of the validation of models, a set of reference simulations. These applications cover a range of building types (residential, commercial) and systems (production, distribution emission) and run in a variety of climates. The paper will describe how models dedicated to these applications were developed, starting from validation results, going through the selection and consolidation of simulation hypothesises and ending with a number that might be considered as reference for the concerned applications. The paper will concentrate on models required by a residential building application (multizone building equipped with a heat pump or a condensing boiler, heat emitted by radiators or floor heating systems). Simulations make use of both EES and TRNSYS software and both software are applied in parallel as far as possible in the different applications in order to get a better judgment of their potential advantages and drawbacks. The use of reference simulations in view of qualifying normative methods currently in development in the frame of the European Energy Performance in Buildings Directive is also addressed and demonstrated in the paper. [less ▲]

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See detailDevelopment of simple cooling coil models for simulation of HVAC systems
Lemort, Vincent ULg; Cuevas, Cristian; Lebrun, Jean ULg et al

in ASHRAE Transactions (2008), 114(1), 319-328

This paper presents two simple cooling coil models. The first part of the paper describes and validates the first one (“reference model”). This model only necessitates 3 parameters, which can be estimated ... [more ▼]

This paper presents two simple cooling coil models. The first part of the paper describes and validates the first one (“reference model”). This model only necessitates 3 parameters, which can be estimated by using commissioning or manufacturer information. The second part of the paper presents and validates the second simple model (“simplified model”). The paper shows how the latter can be built from the reference model, when there is no need to describe what happens on the refrigerant side. This simplified model can be easily integrated in the model of a global HVAC system in order to calculate the cooling coil energy consumption over large time periods. The simplified model is appropriate to decrease the computational time and avoid numerical instabilities. [less ▲]

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See detailMachines et Systèmes Thermiques
Lebrun, Jean ULg; Lemort, Vincent ULg

Learning material (2007)

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See detailEnergy audit of air conditioning systems
Andre, Philippe ULg; Hannay, Cl.; Hannay, J. et al

Conference (2007, June)

The work presented here consists in developing an audit methodology, with appropriate simulation tools and benchmarks. Several case studies are used to support, to test and to illustrate these ... [more ▼]

The work presented here consists in developing an audit methodology, with appropriate simulation tools and benchmarks. Several case studies are used to support, to test and to illustrate these developments. Each case study is described according to a standard format, in order to make the data easy to re-use in the future. The audit of the HVAC system consists in analyzing the information available about actual energy performances and in identifying the most attractive retrofit opportunities. Focus is given here to cooling energy consumption, but it could never be completely dissociated from heating requirements. An example of case study is presented in the paper to give a first idea of what could be the (difficult) task of the energy auditor. One of the main difficulties comes from the too many information lacks. Filling these lacks would require, in most case, more detailed energy records on site. Simulation models may help a lot, for a better interpretation of on site records and also for a safe identification of the most promising retrofit opportunities. Such models and examples of simulations are presented in the paper. [less ▲]

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See detailFriendly simulation of residential heating systems.
Andre, Philippe ULg; Georges, Bernard ULg; Lebrun, Jean ULg et al

Conference (2007, June)

Until now, the choice of a heating system is, in most cases, rather intuitive, but not based on significant comparisons among the many options available on the market. Friendly calculation tools are badly ... [more ▼]

Until now, the choice of a heating system is, in most cases, rather intuitive, but not based on significant comparisons among the many options available on the market. Friendly calculation tools are badly needed. A prototype of simulation model is shortly presented in this paper. It is designed as a preliminary design tool, allowing the different partners of a project to evaluate the energy impact of the very first design options: building envelope heat transfer coefficients, glazing areas, orientations, solar factors, ventilation mode, heat emission, distribution, generation and control strategy. The heating demand is calculated hour by hour with consideration to the time variations of inside and outside temperatures and free gains, to the control law and to the heating power actually available. The emitter is a water-ambient heat exchanger. It may have some thermal mass. Two emitters are here proposed: the radiator and the flow heating system. A steady state water distribution model is included in this simulation; it takes heat losses in unheated spaces into account: Three typical heating sources are proposed: classical boiler, condensing boiler and heat pump. All heat generators are here simulated with the help of very simple polynomial (“daughter”) models. The polynomial expressions are fitted on the simulation results obtained with reference (“mother”) models, themselves fitted on experimental data available. Examples of simulation results are presented in the paper. [less ▲]

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See detailDéveloppement de modèles pour la simulation des systèmes de chauffage, ventilation et conditionnement d'air
Andre, Philippe ULg; Lebrun, Jean ULg; Lemort, Vincent ULg et al

(2007, May)

Les outils de calculs actuellement disponibles permettent de simuler globalement à peu près n’importe quel système de chauffage ou de climatisation sur un pas de temps de l’ordre de l’heure ou moins et ce ... [more ▼]

Les outils de calculs actuellement disponibles permettent de simuler globalement à peu près n’importe quel système de chauffage ou de climatisation sur un pas de temps de l’ordre de l’heure ou moins et ce, sur une année complète ou plus. Encore faut-il que cette simulation fasse bien apparaître les termes dominants du bilan énergétiques et que les paramètres du système aient été correctement identifiés. Quelques principes généraux sont proposés ici et illustrés par des exemples. Deux cas sont envisagés : le chauffage d’une habitation et la climatisation d’un immeuble de bureaux. [less ▲]

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See detailContribution à l'étude des cycles de Rankine de récupération de chaleur
Lemort, Vincent ULg; Cuevas, Cristian; Teodorese, Ion et al

(2007, May)

Ce papier présente tout d’abord un modèle de cycle de Rankine, dont l’expanseur est de type spiro-orbital. Ce modèle doit permettre d’orienter le design des différents éléments du cycle, mais aussi de ... [more ▼]

Ce papier présente tout d’abord un modèle de cycle de Rankine, dont l’expanseur est de type spiro-orbital. Ce modèle doit permettre d’orienter le design des différents éléments du cycle, mais aussi de prédire les performances du cycle pour des conditions opératoires imposées. Une méthode de comparaison des performances réalisées par différents fluides est ensuite proposée. Les résultats d’une étude expérimentale menée sur un prototype de cycle de Rankine de récupération de chaleur sont finalement présentés. Le modèle du cycle et la méthode de comparaison des performances des fluides ont été utilisés pour orienter le design de l’expanseur spiro-orbital et sélectionner le fluide de travail. [less ▲]

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See detailDevelopment and experimental validation of an Organic Rankine cycle model
Lemort, Vincent ULg; Quoilin, Sylvain ULg; Cuevas, Critian et al

(2007)

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

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

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See detailFrom model validation to production of reference simulations: how to increase reliability and applicability of building and HVAC simulation models
Adam, Christophe; Andre, Philippe ULg; Georges, Bernard ULg et al

(2006, December)

Validation of simulation models appears from a long time as a key issue in order to promote a more intensive and more efficient use of simulation models in the field of building and HVAC simulation. IEA ... [more ▼]

Validation of simulation models appears from a long time as a key issue in order to promote a more intensive and more efficient use of simulation models in the field of building and HVAC simulation. IEA Annex 34/43 originally targeted a number of specific applications where a more advanced validation was required: ground coupling problems, multizone building, shading, day lighting and cooling load interaction, HVAC components and ventilated facades. These validation exercises were built on the large methodological experience obtained in previous projects and address sometimes very fundamental problems of heat transfer in buildings. Consulting engineers and practitioners might see these exercises as a bit too far from their objectives and it is the reason why an additional activity was proposed with the specific aim of producing, based upon the results of the validation of models, a set of reference simulations. These applications cover a range of building types (residential, commercial) and systems (production, distribution emission) and run in a variety of climates. The paper will describe how models dedicated to these applications were developed, starting from validation results, going through the selection and consolidation of simulation hypothesises and ending with a number that might be considered as reference for the concerned applications. The paper will concentrate on models required by a residential building application (multizone building equipped with a heat pump or a condensing boiler). Simulations make use of both EES and TRNSYS software and both software are applied in parallel as far as possible in the different applications in order to get a better judgment of their potential advantages and drawbacks. The use of reference simulations in view of qualifying normative methods currently in development in the frame of the European Energy Performance in Buildings Directive is also addressed and demonstrated in the paper. [less ▲]

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See detailA contribution to the audit of an air-conditioning system: modeling, simulation and benchmarking
Adam, Christophe; Andre, Philippe ULg; Hannay, Cleide et al

(2006, December)

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 (building + HVAC) 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 ▲]

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See detailModeling and simulation of an air conditioning chilled water system
Lebrun, Jean ULg; Lemort, Vincent ULg; Teodorese, Ion

(2006, December)

This paper is giving an overview of problems encountered and solutions available for the simulation of an air conditioning system. Focus is given on the chilling water subsystem (from the chiller to the ... [more ▼]

This paper is giving an overview of problems encountered and solutions available for the simulation of an air conditioning system. Focus is given on the chilling water subsystem (from the chiller to the cooling coil). Main component simulation models (chillers, pumps, piping, valves, cooling coils and fans) are presented; they are tuned on manufacturer’s catalogue data. The way of integrating these models into a global HVAC system simulation is illustrated thanks to one example: the simulation of (a part of) a real chilled water loop, which is submitted to an exhaustive monitoring. Cooling demands and corresponding energy consumptions are systematically simulated and measured on one-minute time basis. This provides the opportunity for a global checking of the simulation by comparing simulated and measured cooling coil outputs. Further work should also include comparisons on chiller consumptions. [less ▲]

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See detailCondenser heat recovery in air conditioning systems
Hanus, Vincent; Lebrun, Jean ULg; Lemort, Vincent ULg

(2006, November)

This paper is based on the first Belgian case study developed in the frame of the IEA-ECBCS annex 48 project. It concerns an industrial building in which simultaneous cooling and heating demands subsist ... [more ▼]

This paper is based on the first Belgian case study developed in the frame of the IEA-ECBCS annex 48 project. It concerns an industrial building in which simultaneous cooling and heating demands subsist all along the year: boilers and chillers are working in parallel and nothing is currently done to recover the condensers heat. In such existing building, one of the first energy retrofit to be considered consists in installing a heat pump between the chillers condensers and the hot water distribution, or in making the condensing temperature compatible with heating requirements. The COP of this heat recovery process is expected to overpass 3. Combined with the efficiency of a modern TGV power plant (~55%), this COP makes heat pumping using less than one half of the primary energy consumed by the best boiler available. And the CO2 emission is reduced in proportion… [less ▲]

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See detailSimulation models applicable to HVAC components; parameter identification and system simulation
Lebrun, Jean ULg; Lemort, Vincent ULg; Teodorese, Ion

(2006, November)

A few examples of HVAC component modeling are presented in this paper. Some information is also given about the way to tune and to validate these models. Main “traps” are indicated. The three components ... [more ▼]

A few examples of HVAC component modeling are presented in this paper. Some information is also given about the way to tune and to validate these models. Main “traps” are indicated. The three components are an air-cooled chiller, a cooling coil and a condensing boiler. [less ▲]

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See detailSimulation of HVAC systems: development and validation of simulation models and examples of practical applications
Andre, Philippe ULg; Aparecida, Silva; Hannay, Jules et al

(2006, October)

A survey of some “reference” and “simplified” HVAC component models is presented in this paper. The concepts of model “tuning”, “validation” and “evaluation” are briefly discussed. The parameters of the ... [more ▼]

A survey of some “reference” and “simplified” HVAC component models is presented in this paper. The concepts of model “tuning”, “validation” and “evaluation” are briefly discussed. The parameters of the models are tuned on the basis of manufacturer catalogues and/or experimental data. Mostly “simplified” or “daughter” models are used in global simulation. They are generated from “reference” or “mother” models. The “mother” models are validated in different ways: - Analytically - By comparison with other models - By comparison with experimental data. Both procedures (validation and tuning) are presented in this paper; some typical “traps” are also identified. Examples of validation and of simulation results are also presented. Commissioning and energy audit are the two application domains considered here. [less ▲]

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See detailExample of audit of an air conditioning system.
Andre, Philippe ULg; Rogiest, Corinne ULg; Hannay, Cleide ULg et al

Conference (2006, September)

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 fashion” 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 fashion” air conditioning system with induction units. An audit procedure is developed and tested “in way”. It consists in a systematic analysis of all information available, with help of very simple calculation. Not all the orders of magnitudes of the fuel and mostly of the electricity consumption can be interpreted, but very significant energy saving opportunities are already discovered. [less ▲]

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See detailRéalisation et validation d’un banc du système de refroidissement pour pile à combustible de véhicule
Cuevas, Cristian; Duysinx, Pierre ULg; Hannay, Jules et al

Report (2006)

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See detailHeat pumping and reversible air-conditioning : a new project of the international energy agency.
Afjei, Th.; Andre, Philippe ULg; Halozan, H. et al

in Bertoldi, Paolo; Atanasiu, Bogdan (Eds.) Proceeding of the international conference IEECB'06 (2006)

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See detailAbout the audit of air conditioning systems : customer advising with the help of case studies and benchmarks, modelling and simulation
Alexandre, José Luis; Knight, Ian; Andre, Philippe ULg et al

in Bertoldi, Paolo; Atanasiu, Bogdan (Eds.) Proceeding of the international conference IEECB'06 (2006)

Detailed reference viewed: 21 (2 ULg)