References of "Bertagnolio, Stéphane"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailInvestigation on a ventilation heat recovery exchanger: Modeling and experimental validation in dry and partially wet conditions
Gendebien, Samuel ULg; Bertagnolio, Stéphane ULg; Lemort, Vincent ULg

in Energy & Buildings (2013), 62

The present paper focuses on the development and experimental validation of a model of air-to-air heat exchanger dedicated to domestic mechanical heat recovery ventilation. The proposed model describes ... [more ▼]

The present paper focuses on the development and experimental validation of a model of air-to-air heat exchanger dedicated to domestic mechanical heat recovery ventilation. The proposed model describes dry and partially wet regimes. The first part of the paper presents a semi-empirical model based on the physical characteristics of the heat recovery device and relying on empirical correlations available in the literature for the convective heat transfer coefficients. In the case of partially wet regime, a moving boundary model is applied in order to predict sensible and latent heat transfer rates. A model developed with friction factor coefficients estimated by correlations from the literature is also presented in order to predict the hydraulic performance in dry conditions. The second part of the paper describes the experimental investigation conducted on an off-the-shelf heat exchanger. Experimental data are used to tune correlations for the determination of the convective heat transfer coefficient and validate the proposed simulation model of the ventilation heat recovery exchanger in partially wet conditions. The model developed to determine the hydraulic performance with existing correlations for the friction factor coefficient does not require a calibration. Finally, examples of use of the developed model are presented, which includes coupling the model with a building simulation model, a study of the influence of the humidity on the evolution of the latent and sensible heat transfer rates and strategies to avoid freezing in the heat exchanger. [less ▲]

Detailed reference viewed: 80 (35 ULg)
Full Text
Peer Reviewed
See detailModeling and simulation of the domestic energy use in Belgium following a bottom-up approach
Georges, Emeline ULg; Gendebien, Samuel ULg; Bertagnolio, Stéphane ULg et al

in Proceedings of the CLIMA 2013 11th REHVA World Congress & 8th International Conference on IAQVEC (2013, June)

The present paper presents a “bottom-up” approach dedicated to the modeling and simulation of the domestic energy use. This methodology focuses first on a microanalysis (i.e. modeling and simulation of a ... [more ▼]

The present paper presents a “bottom-up” approach dedicated to the modeling and simulation of the domestic energy use. This methodology focuses first on a microanalysis (i.e. modeling and simulation of a set of representative households). Results from this micro-analysis are then used and extended to allow drawing conclusions at a macro-scale. The methodology can be validated by comparing simulation results to annual national energy consumption indexes or synthetic load profiles (energy consumption profiles generated from values of predefined past periods). Once the method is validated, it can be used to study the impact of different retrofit scenarios on the annual energy use and on the energy demand profiles. This paper describes the methodology developed for Belgium. [less ▲]

Detailed reference viewed: 90 (26 ULg)
Full Text
Peer Reviewed
See detailSimulation-assisted evaluation of potential energy savings: Application to an administrative building in France
Randaxhe, François ULg; Bertagnolio, Stéphane ULg; Lemort, Vincent ULg

in Randaxhe, François; Bertagnolio, Stéphane; Lemort, Vincent (Eds.) International Conference for Enhanced Building Operations ICEBO 2012 at Manchester, October 23-26, 2012 (2012, October)

The case study presented here falls within a project of feasibility studies to improve the energy efficiency, the carbon footprint and the environmental impacts of several administrative buildings in ... [more ▼]

The case study presented here falls within a project of feasibility studies to improve the energy efficiency, the carbon footprint and the environmental impacts of several administrative buildings in France. The first part of the paper briefly presents the data obtained during a classical audit and inspection procedure: the description of the building in term of design, the HVAC system characteristics, the occupancy and operating profiles and the control strategy applied. The second part of the paper gives the first results obtained using an evidence-based calibrated building energy simulation model to analyze the actual building global consumption but also analyze the local consumptions (heat pumps, air handling units, terminal units, lightings, pumps,...). The last part of the paper then demonstrates the possibilities given by the building energy simulation model to evaluate potential energy saving scenarios through different examples. The advantages and drawbacks of the applied methods and tools are also discussed. [less ▲]

Detailed reference viewed: 36 (9 ULg)
Full Text
Peer Reviewed
See detailGlobal Sensitivity Analysis applied to Total Energy Use in Buildings
Ruiz Flores, Roberto ULg; Bertagnolio, Stéphane ULg; Lemort, Vincent ULg

in Proceedings of the 2nd International High Performance Buildings Conference (2012, July 16)

The work presented in this paper has been carried out in the frame of the IEA-ECBCS Annex 53 project: “Total Energy Use in Buildings: Analysis and evaluation methods”. The aim of this work is to present a ... [more ▼]

The work presented in this paper has been carried out in the frame of the IEA-ECBCS Annex 53 project: “Total Energy Use in Buildings: Analysis and evaluation methods”. The aim of this work is to present a methodology to identify the most influential parameters affecting the final energy consumption in office buildings. In order to represent buildings and HVAC systems, a representative typology was defined, modeled and simulated and subsequently a global sensitivity analysis (variance-based method) was performed. This paper provides useful information to future works related to design building decisions, building calibration, energy management strategy, etc. helping to detect and rank those factors which need to be better measured and/or estimated, in order to improve building energy efficiency. [less ▲]

Detailed reference viewed: 487 (34 ULg)
Full Text
Peer Reviewed
See detailEnergy and comfort performance analysis of monitored thermally activated building systems combined with geothermal heat pumps
Gantiez, Clément ULg; Lemort, Vincent ULg; Hoogmartens, Jan et al

in International High Performance Buildings Conference at Purdue, July 16-19, 2012 (2012, July)

The combination of geothermal heat pumps (GEO HPs) and thermally activated building systems (TABS), that allow both low temperature heating and high temperature cooling, could yield primary energy savings ... [more ▼]

The combination of geothermal heat pumps (GEO HPs) and thermally activated building systems (TABS), that allow both low temperature heating and high temperature cooling, could yield primary energy savings of around 20- 71% in comparison with conventional heating/cooling systems. However, the potential energy savings are rarely reached in practice due to bad integration of the different subsystems and inefficient control. The present paper presents the analysis of two monitoring campaigns by stressing the influence of relevant parameters such as the performance of components (heat pump, ground heat exchangers, TABS, etc.), building characteristics and the implemented control strategies. The buildings have been monitored and analyzed in the frame of the WKSP-project realized by Institute of Building Services and Energy Design (IGS) at Technical University of Braunschweig. The results show good performance of ground coupled heat pump with seasonal COP up to around 5. Moreover, the use of ground heat exchangers to perform free chilling allows seasonal EER up to 20. Furthermore, the control strategies implemented in the different buildings are quite different. It is also shown that this system can lead to a running cost reduction up to 50% compared to conventional systems and that CO2 emissions can be reduced by 40%. [less ▲]

Detailed reference viewed: 47 (13 ULg)
Full Text
See detailEvidence-Based Model Calibration for Efficient Building Energy Services
Bertagnolio, Stéphane ULg

Doctoral thesis (2012)

Energy services play a growing role in the control of energy consumption and the improvement of energy efficiency in non-residential buildings. Most of the energy use analyses involved in the energy ... [more ▼]

Energy services play a growing role in the control of energy consumption and the improvement of energy efficiency in non-residential buildings. Most of the energy use analyses involved in the energy efficiency service process require on-field measurements and energy use analysis. Today, while detailed on-field measurements and energy counting stay generally expensive and time-consuming, energy simulations are increasingly cheaper due to the continuous improvement of computer speed. This work consists in the development of a simulation-based approach dedicated to whole-building energy use analysis for use in the frame of an energy efficiency service process. Focus is given to the development of a new simplified dynamic hourly building energy simulation tool adapted to energy use analysis of existing buildings, its calibration by means of available energy use data and to the integration of the calibration process into the Energy Service Process. The proposed evidence-based calibration methodology is deeply related to on-field inspection and data collection issues and is developed to fit with the audit/inspection process. After calibration, the model can be used to support the other steps of the Energy Services Process, such as ECOs selection and evaluation and continuous performance verification. The new systematic calibration methodology gives priority to the physical identification of the model’s parameters (i.e. to the direct measurement) and relies on the notion of hierarchy among the source of information (as a function of their reliability) used to identify the value of the parameters. The improved Morris’ sensitivity analysis method is used for “factor fixing” (i.e. distinction between non-influential model’s parameters) and “parameters screening” (i.e. classification of influential parameters by order of importance) in order to orient the data collection work and guide the parameters adjustment process. At the end of the calibration process, the Latin Hypercube Monte Carlo sampling is used to quantify the uncertainty on the final outputs of the calibrated model. The developed simulation tool and the associated calibration method are applied to a synthetic case (“Virtual Calibration Test Bed”) and to real case study building located in Brussels, Belgium. Both applications (real and synthetic cases) allow highlighting the complexity and the limits of calibration as it is used today. Calibration remains a highly underdetermined problem and a compromise has to be found between data collection and modeling efforts and model’s requirements in order to proceed to efficient energy use analysis. At the end of these applications, it is believed that partially manual methods remain more efficient and the best quality assurance when proceeding to calibration of a building energy simulation model. The use of an evidence-based method ensures sticking to reality and avoids bad representation and hazardous adjustment of the parameters. Moreover, it is shown that the intensive use of a sensitivity analysis method is of a great help to orient data collection and parameters adjustment processes. Defining confidence/uncertainty ranges for each parameter, in addition to a “best-guess” value, also allowed quantifying the uncertainty on the final outputs of the model and helped the user in evaluating the quality of the calibrated model. [less ▲]

Detailed reference viewed: 98 (28 ULg)
Full Text
Peer Reviewed
See detailComparing vertical ground heat exchanger models
Bertagnolio, Stéphane ULg; Bernier, Michel; Kummert, Michaël

in Journal of Building Performance Simulation [=JBPS] (2012)

The main objective of this article is to establish a set of test cases for analytical verification and inter-model comparison of vertical ground heat exchanger (GHX) models used in building simulation ... [more ▼]

The main objective of this article is to establish a set of test cases for analytical verification and inter-model comparison of vertical ground heat exchanger (GHX) models used in building simulation programs. Several test cases are suggested. They range from steady-state heat rejection in a single borehole to varying hourly loads with relatively large yearly thermal imbalance in multiple borehole configurations. The usefulness of the proposed test cases is illustrated with different GHX models. This comparison exercise has shown that analytical one-dimensional (1D) models compare favourably well with three-dimensional (3D) models for relatively short-simulation periods, where axial effects are not significant. Cyclic heat rejection/collection tests proved to be useful to characterize the accuracy and the computational performance of different load aggregation algorithms. Finally, different spatial superposition methods have been compared for various bore field sizes and configurations and various loads. [less ▲]

Detailed reference viewed: 128 (30 ULg)
Full Text
Peer Reviewed
See detailModeling and experimental validation in partially wet conditions of an air-to-air heat recovery exchanger
Gendebien, Samuel ULg; Bertagnolio, Stéphane ULg; Lemort, Vincent ULg

in Proceedings of the 12th Conference of The International Building Performance Simulation Association (2011, November)

Nowadays, important efforts are deployed to reduce our current residential building consumption. The most common retrofit option concerns the air tightness and the thermal insulation improvement. However ... [more ▼]

Nowadays, important efforts are deployed to reduce our current residential building consumption. The most common retrofit option concerns the air tightness and the thermal insulation improvement. However, this latter retrofit option could decrease the air indoor quality because of a reduction of air infiltration flow rate. Installation of an air-to-air heat recovery system allows for an efficient combination between consumption reduction due to the air tightness improvement and acceptable air indoor quality. The study presented in this paper has been realized in the frame of the „Green +‟ project, which aims at developing decentralized heat recovery ventilation systems. The present paper focuses on modeling and experimental validation of an air-to-air heat recovery exchanger in partially wet conditions (i.e. where condensation might occur in one of the two air streams). The knowledge of the thermal performance in dry and wet regimes is essential since it highly impacts on the heat recovered from the vitiated air flow rate (extracted from the building) to the fresh air flow rate (coming from the outdoor). The first part of the paper briefly describes a solving procedure able to determine the regime (completely dry, completely wet and partially wet). A moving boundary model for the partially wet regime is applied in order to predict performance of such device. Secondly, the experimental apparatus (and its control) designed to characterize thermal performance in different operating conditions (dry and wet regime) is presented. [less ▲]

Detailed reference viewed: 82 (26 ULg)
Full Text
Peer Reviewed
See detailInvestigation on an air-to-air heat recovery exchanger: modeling and experimental validation in dry conditions
Gendebien, Samuel ULg; Bertagnolio, Stéphane ULg; Georges, Bernard ULg et al

in Proceedings of the RoomVent 2011 Conference (2011, June 21)

This paper deals with the development and the experimental validation of an air-to-air recovery heat exchanger model dedicated to ventilation of residential buildings. The first part of the paper presents ... [more ▼]

This paper deals with the development and the experimental validation of an air-to-air recovery heat exchanger model dedicated to ventilation of residential buildings. The first part of the paper presents a semi-empirical model based on physical characteristics of the heat exchanger. The aim of this model is to predict the behavior of the device in dry conditions. The second part of the paper describes the experimental facility designed to determine the hydraulic and thermal performance of the device and offers a comparison between simulation and experimental results. Finally, the model is calibrated in order to predict the thermal and hydraulic performance of the heat exchanger within respectively, less than 5% and less than 2% of accuracy. [less ▲]

Detailed reference viewed: 67 (24 ULg)
Full Text
Peer Reviewed
See detailAssessing overall heating efficiency of office buildings
Parys, Wout; Bertagnolio, Stéphane ULg; Saelens, Dirk et al

in Lemort, Vincent; Andre, Philippe; Bertagnolio, Stéphane (Eds.) 8th Conference on System Simulation in Buildings (2010, December 13)

The current methodology applied to estimate system efficiencies oversimplifies the complex interaction between the building, the occupants and the system. By detailed modelling of the building and the ... [more ▼]

The current methodology applied to estimate system efficiencies oversimplifies the complex interaction between the building, the occupants and the system. By detailed modelling of the building and the system, it is possible to define system efficiencies at the building level as a function of the system type and the building characteristics. In this study, the performance of a simple heating system in a middle-sized office building is simulated. The monthly average total efficiency, defined at the building level, proves to be very well correlated with the monthly ratio of heat gains over heat losses of the building. At ratios over 0.6, the efficiency falls sharply. This is mainly due to declining control efficiency. This secondary effect can annul partly the targeted increase in energy efficiency of well insulated and airtight buildings. [less ▲]

Detailed reference viewed: 44 (7 ULg)
Full Text
See detailA Generalized Simulation Model of Chillers and Heat Pumps to be Calibrated on Published Manufacturer's Data
Lemort, Vincent ULg; Bertagnolio, Stéphane ULg

(2010, August 07)

This paper shows how semi-empirical models of chillers and heat pumps can be calibrated on the basis of manufacturer’s published data, which is most of the time the only available source of information. A ... [more ▼]

This paper shows how semi-empirical models of chillers and heat pumps can be calibrated on the basis of manufacturer’s published data, which is most of the time the only available source of information. A calibration methodology is proposed and illustrated for different technologies of vapor-compression machines, pointing out tips and tricks. Whatever the size and technology (e.g. scroll, screw or reciprocating compressors), the semi-empirical model is found to predict both full load and part load performance with a very good accuracy. This is partially due to the tailor-made formalism of the model, which allows describing the main features of the machine. [less ▲]

Detailed reference viewed: 116 (40 ULg)
Full Text
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 ▲]

Detailed reference viewed: 38 (17 ULg)
Full Text
Peer Reviewed
See detailRadiant ceiling systems coupled to its environment part 2: Dynamic modeling and validation
Fonseca, Nestor; Bertagnolio, Stéphane ULg; Cuevas, Cristian

in Applied Thermal Engineering (2010), 30

This paper presents the results of a study performed in order to develop a dynamic model of radiant ceiling panels in heating or cooling modes coupled to its environment (fenestration, walls, internal ... [more ▼]

This paper presents the results of a study performed in order to develop a dynamic model of radiant ceiling panels in heating or cooling modes coupled to its environment (fenestration, walls, internal loads and ventilation system). The model considers the radiant panels as a dynamic-state finned heat exchanger connected to a detailed lumped dynamic model of the building (ReC network). The behavior of the radiant ceiling system and the interactions with its environment has been experimentally and numerically evaluated. Using as inputs the radiant ceiling and room dimensions, material properties and the transient measurements of air temperature at the adjacent zones, supply air and water temperatures and mass flow rates, the model allows for the estimation of the water exhaust temperature, radiant ceiling average surface temperature, resultant and dry air room temperatures, radiant ceiling power and internal surface temperatures of the room in order to compare with measurements taken during the commissioning process. Two dynamic tests in heating and cooling modes are used to validate the model. [less ▲]

Detailed reference viewed: 63 (16 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 377 (44 ULg)
Full Text
Peer Reviewed
See detailDevelopment of an Evidence-Based Calibration Methodology Dedicated to Energy Audit of Office Buildings. Part 2: Application to a typical office building in Belgium
Andre, Philippe ULg; Fabry, Bertrand ULg; Bertagnolio, Stéphane ULg et al

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

The development of specific tools for the audit of air-conditioning systems is described in a companion paper. These developments are carried out in the frame of the HarmonAC project launched in 2007 in ... [more ▼]

The development of specific tools for the audit of air-conditioning systems is described in a companion paper. These developments are carried out in the frame of the HarmonAC project launched in 2007 in order to assist the implementation of the EPBD, article 9. The development of these tools was continously supported by the application to case studies. This paper reports on the application of the tools within an audit procedure applied to a typical office building in Belgium, which is in operation for more than 20 years. The first step of the work consisted in analyzing the current performance of the building which proved to point out a number of problems in the operation of the building. As it is not rarely the case for running office buildings, these problems were due to a lack of commissioning and a progressive decrease of the performances due to a poor management. Application of the first stage “Benchmark” tool to this building led to a very high discrepancy between the measured consumptions and the calculated ones. This appeared mainly for the electricity consumption but also for the gas consumption. Calibration of the simulation tool, mainly by representing more exactly the management of the building and the real internal gains improved the accuracy of the calculations to a large extent. After calibration of the building and HVAC model, the application of a second tool (SimAudit) allowed to evaluate the savings obtained by the implementation of a number of Energy Conservation Opportunities (ECOs). In this case, the dominant ECOs were in relation with the operation of the building: change of schedules, modification of setpoints; implementation of free-cooling strategies; provision of heat recovery and move to reversibility of the chillers. Reasonable estimates of the savings can be obtained following the calibration/simulation process. The paper will highlight some of the most relevant ECOs and provide an order of magnitude for the savings in this kind of building and in a mild climate. [less ▲]

Detailed reference viewed: 76 (14 ULg)
Full Text
Peer Reviewed
See detailSimulation Based Assessment of Heat Pumping Potential in Non-Residential Buildings – Part 1: Modeling
Bertagnolio, Stéphane ULg; Stabat, Pascal; Soccal, Benjamin et al

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

1 Introduction A solution to reduce the energy consumption in office and health care buildings consist in better exploiting the potential of the heat pump technology. This can be done by recovering heat ... [more ▼]

1 Introduction A solution to reduce the energy consumption in office and health care buildings consist in better exploiting the potential of the heat pump technology. This can be done by recovering heat at the condenser when the chiller is used to produce cold (simultaneous heating and cooling demands) or by using the chiller in heat pump mode (non-simultaneous heating and cooling demands). Both strategies appear particularly feasible when cooling and heating needs and the heat pump technology are, at least partly, present in the building, which is often the case in the tertiary sector. The analysis of these reversibility and recovery potentials is one of the subjects of the IEA-ECBCS Annex 48 project. 2 Simulation tools A package of simulation tools is developed in order to assess the energy and environmental performances and costs of such solutions. A first tool allows a quick estimation of the potential of recovery and reversibility options, starting with limited information and using a limited amount of parameters. It consists in simulating the considered building and its secondary HVAC system in order to generate hourly values of heating and cooling system loads and to compute theoretical reversibility and recovery potentials. This first simulation run can be performed by mean of a calibrated building energy simulation tool (Trnsys, Energyplus…). Hourly values of heating and cooling loads of a given building can also be obtained through in-situ measurements. A second tool allows to simulate the behavior of the heat pump plant and to compute its performances using the previously computed heating and cooling load profiles as inputs. The considered heat pump configuration is then compared to a classical HVAC primary system (composed of a boiler and a chiller) in terms of primary energy consumption, CO2 emissions and costs. In this first paper, the development of such models and their implementation in an equation-based solver are described. The considered heat pump configurations are presented and the models of the main components (heat pump, boiler, thermal storage system, cooling tower and ground heat exchanger) are described. Five general configurations are considered: (1) reversible air-to-water heat pump, (2) exhaust air heat pump, (3) dual condenser heat pump, (4) water loop systems and (5) ground coupled heat pump. The modeling hypotheses, the control algorithms and the connection of these models into global heat pump systems simulation models are discussed. Finally, it is shown how simple equation-based simulation models can be connected to allow quick and robust assessment of the potential of complex heat pump systems. [less ▲]

Detailed reference viewed: 150 (25 ULg)
Full Text
Peer Reviewed
See detailSimulation Based Assessment of Heat Pumping Potential in Non-Residential Buildings – Part 2: Parametric Study
Bertagnolio, Stéphane ULg; Stabat, Pascal; Gendebien, Samuel ULg et al

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

This paper is the second one in a series of three papers presenting the assessment methodology of heat pump systems developed in the frame of the IEA-ECBCS Annex 48 project. A package of simulation tools ... [more ▼]

This paper is the second one in a series of three papers presenting the assessment methodology of heat pump systems developed in the frame of the IEA-ECBCS Annex 48 project. A package of simulation tools is developed in order to assess the energy and environmental performances and costs of various reversibility and heat recovery solutions dedicated to space heating and cooling. This paper presents the results of an extended parametric study aiming in assessing the potential of the considered heat pump systems in the European building stock. [less ▲]

Detailed reference viewed: 77 (12 ULg)
Full Text
Peer Reviewed
See detailSimulation Based Assessment of Heat Pumping Potential in Non-Residential Buildings – Part 3: Application to a typical office building in Belgium
Fabry, Bertrand ULg; Andre, Philippe ULg; Bertagnolio, Stéphane ULg et al

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

The purpose of this paper is to describe the application of the tools presented in a companion paper [1] to a typical office building located in the Walloon Region of Belgium. This building is a mid-size ... [more ▼]

The purpose of this paper is to describe the application of the tools presented in a companion paper [1] to a typical office building located in the Walloon Region of Belgium. This building is a mid-size (7000 m² on seven floors) office building constructed in the eighties and equipped with a classical HVAC solution: boiler and air-cooled chiller; all-air VAV system. An energy audit was conducted in this building and featured a number of management problems. Among the Energy Conservation Opportunities considered to improve the energy performance of the building, the move to a heat pump solution was considered. The identification of energy savings potential offered by the implementation of heat pumping strategies confirmed what was already shown by the parametric analysis: in temperate climates, reversibility offers a by far higher potential than condenser heat recovery given the dominant non simultaneity of the yearly heating and cooling demands profiles. Calculations show that theoretically half of the heating demand could be satisfied by the reversibility of the chiller to run in heat pumping mode. In a second step, a number of practical implementations of heat pumping solutions were evaluated by means of another software tool: reversible air/water HP, exhaust air HP, double condenser and water loop heat pump systems. These solutions are compared to the reference existing situation (boiler + chiller working independently) in terms of energy, CO2 emissions and cost on a 20 years life-cycle basis. Calculations show that the air/water reversible chiller solution offers the most important energy savings and CO2 reduction while staying at a reasonable level concerning the additional cost. [less ▲]

Detailed reference viewed: 71 (7 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 129 (34 ULg)
Full Text
Peer Reviewed
See detailDevelopment of an Evidence-Based Calibration Methodology Dedicated to Energy Audit of Office Buildings. Part 1: Methodology and Modeling.
Bertagnolio, Stéphane ULg; Andre, Philippe ULg

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

1 Introduction To promote improvements in the HVAC installations of existing buildings, the article 9 of the EPBD directive establishes mandatory audits and inspections of air-conditioning systems. The ... [more ▼]

1 Introduction To promote improvements in the HVAC installations of existing buildings, the article 9 of the EPBD directive establishes mandatory audits and inspections of air-conditioning systems. The development of auditing tools and procedures and the training of future auditors are the main objectives of the HARMONAC project launched in 2007. Four audit stages are generally distinguished: benchmarking, inspection, detailed audit and investment grade audit. Answering the questions encountered along the audit process requires some diagnosis, which has to be established on the basis of the very scarce information currently available: technical data contained in as-built files actually available and, generally, very global recordings of energy consumptions. A dynamic hourly building energy simulation (BES) model is being developed in the frame of the HARMONAC project to help the auditor in establishing his diagnosis despite of the lack of data. Two simulation tools dedicated to assist the auditor are developed on the basis of this equation-based BES model: - The first tool is dedicated to a preliminary benchmarking of the installation. - The second tool is used from inspection stage to evaluation of selected energy conservation measures (ECMs). 2 Simulation-based audit methodology The first step of the audit methodology consists in gathering the as-built and utility data, applying a first treatment and analysis method to this data and using the BES model to perform benchmarking. For this benchmarking targeted work, the actual building is coupled to a typical HVAC system whose performances are defined according to EPBD standards. If the benchmarking indicates that potential energy savings should be studied in the building, the calibration-based audit procedure is launched. In the second step, the BES model is integrated in an iterative evidence-based calibration method adapted to audit purposes. The calibration starts directly at the beginning of the inspection, before realizing any additional measurement. This calibration process includes sensitivity and measurement issues, in order to help the auditor identifying critical points and understanding the building operation. Graphical and statistical methods are used in order to quantify and evaluate if the calibrated baseline model satisfies the predefined tolerances. Finally, the calibrated baseline model can be used to evaluate ECMs and savings uncertainty. The development and the implementation of the BES model are presented in this paper. The mains issues of the proposed calibration-based audit methodology are discussed. An example of application of the whole methodology (from benchmarking to evaluation of ECMs) is presented in a companion paper. [less ▲]

Detailed reference viewed: 297 (19 ULg)