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Jobard Xavier

Chargé Ra&D HES

Main skills

Simulation thermique dynamique

Chargé Ra&D HES

Desktop: S135a

Haute école d'Ingénierie et de Gestion du Canton de Vaud
Route de Cheseaux 1, 1400 Yverdon-les-Bains, CH

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Ongoing

Fostering increased DHN penetration: maximizing renewable share, decreasing temperature levels, identify synergies and integrate multiple injection points on the territory

AGP

Role: Collaborator

Requérant(e)s: Capezzali Massimiliano, IESE

Financement: DIREN; VS - Institut Energie et environnement; Auto-fin IESE; Services Industriels de Lausanne; SFOE; Services Energies Yverdon

Description du projet : District heating networks (DHN) represent a crucial technology to attain significantly lower carbon footprint of the heating sector. Existing grids and their extensions, as well as new projects, are ex-pected to decrease distribution temperature levels decrease, in order to both improve efficiency and integrate a larger share of renewable and waste heat energy sources. The latter need to be quantita-tively characterized in order to be optimally integrated. In parallel, the potential synergies existing among small networks ' e.g. covering a few building blocks or one neighbourhood - need to be exploited, in terms of resources temporal availability and specific demand load profiles, in order to provide dynamic support, including possible storage capacities. FOSTER_DHN aims at developing the corresponding multi-grid and multi-temperatures design and simulation approaches as to gain a systemic understanding of DHN deployment and provide decision-support for local authorities and utilities.

Research team within HES-SO: Duret Alexis , Capezzali Massimiliano , Fesefeldt Marten , Jobard Xavier

Partenaires académiques: IGT; CREM; Capezzali Massimiliano, IESE

Durée du projet: 31.10.2022 - 31.05.2024

Montant global du projet: 110'265 CHF

Statut: Ongoing

Tâche IEA-SHC 68 - Efficient Solar District Heating Systems

AGP

Role: Collaborator

Financement: IGT; OFEN

Description du projet : The objective of Task 68 is to promote the use of solar heat in DHN and to support the penetration of solar heat. Task 68 pursue mainly four objectives: 1. Efficiently providing the heat at the desired temperature level of district heating grids either directly through solar technologies or indirectly through a combination with other technologies (e.g. heat pumps) focusing on the system aspect. 2. Increasing the degree of digitalization of SDH systems in order to achieve a more efficient integration into district heating systems and a more efficient processing and use of data for evaluation, advanced controls and automatic fault detection. 3. Reducing costs of solar thermal plants to increase their economic attractiveness and competitiveness, and developing new financing and business models. 4. Disseminating the knowledge and results about the potential, areas of application, different solar technologies and their efficient combination with other technologies

Research team within HES-SO: Duret Alexis , Jobard Xavier

Durée du projet: 04.10.2022 - 28.02.2025

Montant global du projet: 23'360 CHF

Statut: Ongoing

Solar energy neighborhoods ' Optimal design and operation of heat, cold and electricity supply on the neighborhood scale

AGP

Role: Main Applicant

Financement: IGT; OFEN (Office fédéral de l'énergie)

Description du projet : This project aims to develop smart planning methods and control strategies for high-performance solar neighborhoods. The supply with heat, cold and electricity of such neighborhoods shall make optimal use of solar energy technologies, storage solutions, and the interconnection of the buildings via electrical and thermal grids. A special focus is on the winter heat supply, and the search for effi-cient alternatives to air/water and geothermal heat pump systems. Exploiting synergies and sector coupling at the neighborhood scale will allow to reduce the carbon-intensive winter electricity de-mand and to provide a high load and production flexibility towards the electricity grid. The technical approach is the development of efficient computational models that allow a) to com-pare a large number of system variants in the design phase with regard to different objective func-tions (costs, emissions, grid flexibility) and b) to realize model-predictive control strategies on a neighborhood scale.

Research team within HES-SO: Lasvaux Sébastien , Pham Stéphanie , Capezzali Massimiliano , Fesefeldt Marten , Jobard Xavier , Clot Nathalie , Goulouti Kyriaki , Pauletta Stefano , Frossard Mija

Partenaires académiques: IESE; SPF Institut für Solartechnik

Partenaires professionnels: ponzio solar SA

Durée du projet: 31.08.2021 - 31.01.2024

Montant global du projet: 99'043 CHF

Statut: Ongoing

Couplage direct d'un champ de modules PVT avec un système PAC utilisant des réfrigérants naturels pour le chauffage des bâtiments d'habitation collectif et la production d'eau chaude sanitaire

AGP

Role: Collaborator

Financement: IGT; OFEN; Socle HEIG-VD Ra&D; IGT

Description du projet : L'objectif du projet TrisSolHP est de développer et d'évaluer les performances énergétiques, financières et environnementales, d'un système modulable de production de chaleur pour les bâtiments collectifs existant combinant en série une installation PVT avec une PAC R744 pour la production d'ECS et une PAC R290 pour le chauffage. L'utilisation de collecteur PVT spécialement optimisé pour maximiser l'échange de chaleur convectif avec l'air, permet de limiter la surface nécessaire. La combinaison de PAC utilisant des réfrigérants naturels permet de conserver de bons COP pour la production d'ECS et pour le chauffage sur une large gamme de température de source froide. Un COP annuel de 3.5 est visé. Le système de chauffage TriSolHP représente une alternative attrayante au PAC Air/Eau et pourrait contribuer à la décabornisation de la production de chaleur des bâtiments collectifs existants. Ce concept permet aussi de maximiser l'utilisation des toitures pour valoriser la ressource solaire.

Research team within HES-SO: Duret Alexis , Citherlet Stéphane , Dupont Gabriel , Da Riva Enrico , Guillaume Martin , Jobard Xavier , Pauletta Stefano

Partenaires professionnels: Groupe Système Energétique (GSE), UNIGE

Durée du projet: 31.08.2021 - 31.10.2023

Montant global du projet: 122'903 CHF

Statut: Ongoing

Case studies Romandie: strategies and potentials of temperature reduction on existing district heating networks

AGP

Role: Collaborator

Requérant(e)s: IGT

Financement: OFEN

Description du projet : While reduction of DH (district heating) temperature is a priority for integration of renewable heat, it is conditioned by the temperature level of the individual substations. This issue is of particular concern for existing buildings, where distribution temperatures are known to be high, and where corrective actions within inhabited spaces is of particular complexity. Several techniques for temperature reductions at substation level have been proposed or are currently under investigation, but their actual implementation on existing DH substations depends to a large extent on pre-existing conditions. Furthermore, the actual benefit of temperature reduction at the level of the DH network, as well as interaction between temperature reduction strategies and other energy policy measures, need to be analyzed on specific case studies. Within this WP, these issues will be tackled by means of case studies on existing DH systems, in urban and rural context, requiring close collaboration with our cooperation partners.

Research team within HES-SO: Duret Alexis , Lasvaux Sébastien , Jobard Xavier , Masset Olivier

Partenaires professionnels: IGT

Durée du projet: 07.06.2021 - 31.12.2024

Montant global du projet: 40'000 CHF

Url of the project site: https://www.sweet-decarb.ch

Statut: Ongoing

OPTIM-EASE - Optimisation de la gestion énergétique d'ensemble de bâtiments incluant les impacts environnementaux et le couplage sectoriel, financement FOGA

AGP

Role: Main Applicant

Financement: FOGA; Provision 2022

Description du projet : Le concept énergétique optimal d'un groupe de bâtiments est différent de la somme des concepts optimaux des bâtiments considérés séparément. Le projet OPTIM-EASE développe un cadre méthodologique permettant l'optimisation énergétique de groupes de bâtiments en utilisant leurs synergies. En comparant la solution optimale d'un groupe de bâtiments avec la somme des solutions optimales des bâtiments individuels, les gains économiques et environnementaux de l'agrégation de bâtiments sont caractérisés. il s'agit, ici du financement accordé par le FOGA pour étudier spécifiquement dans le cadre du projet OPTIM-EASE, les aspect liés au gaz renouvelable: - Quantifier la contribution du gaz renouvelable au virage énergétique suisse en réduisant l'impact environnemental de la demande énergétique des groupes de bâtiments (thermique et électrique) - Développement de systèmes multi-énergie décentralisés pour des groupes de bâtiments comprenant des appareils fonctionnant au gaz renouvelable (cogénération, chaudière à gaz à haut rendement, petit réseau de chauffage urbain, etc.) - Identification des options les plus appropriées pour l'intégration du gaz renouvelable dans le concept énergétique via des méthodes d'optimisation multi-objectif, y compris la minimisation des coûts et de l'impact environnemental

Research team within HES-SO: Wagner Guy , Duret Alexis , Loperetti Murielle , Lasvaux Sébastien , Pham Stéphanie , Capezzali Massimiliano , Bürer Mary Jean , Fesefeldt Marten , Jobard Xavier , Goulouti Kyriaki , Frossard Mija

Partenaires académiques: Fachhochschule Ostschweiz; IESE; IGT

Durée du projet: 13.04.2021 - 31.03.2023

Montant global du projet: 37'000 CHF

Statut: Ongoing

OPTIM-EASE - Optimisation de la gestion énergétique d'ensemble de bâtiments incluant les impacts environnementaux et le couplage sectoriel

AGP

Role: Main Applicant

Financement: Fachhochschule Ostschweiz; Romande Energie SA; IGT; Office Fédéral de l'Energie (OFEN); Energie 360° AG ; St.Galler Stadtwerke - SGSW; Provision 2022

Research team within HES-SO: Wagner Guy , Duret Alexis , Loperetti Murielle , Lasvaux Sébastien , Pham Stéphanie , Capezzali Massimiliano , Fesefeldt Marten , Jobard Xavier , Clot Nathalie , Goulouti Kyriaki , Pauletta Stefano , Frossard Mija , Demonchy Gauthier

Partenaires professionnels: Helion Solar Ouest SA; Swissolar; VSG Verband der Schweiz. Gasindustrie; Powerloop - Schweizerischer Fachverband

Durée du projet: 13.04.2021 - 31.03.2023

Montant global du projet: 114'400 CHF

Statut: Ongoing

Completed

Potentiel du solaire thermique dans les chauffages

AGP

Role: Collaborator

Requérant(e)s: IGT

Financement: Socle HEIG-VD Ra&D; Auto-fin IGT; OFEN

Description du projet : Le but du projet SolCAD est d'analyser les opportunités et les limitations du développement du solaire thermique pour les chauffages à distance en Suisse. Pour produire l'évaluation la plus complète possible, quatre approches complémentaires sont utilisées : a) Une approche archétypale et cartographique à grande échelle, b) Une approche par étude de cas, c) Une analyse socio-économique des conditions-cadres et d) Une approche basée sur le partage d'expérience.

Research team within HES-SO: Wagner Guy , Duret Alexis , Citherlet Stéphane , Guillaume Martin , Jobard Xavier , Masset Olivier

Partenaires académiques: IGT

Durée du projet: 01.10.2019 - 26.11.2021

Montant global du projet: 87'046 CHF

Statut: Completed

Ecobilan Dynamique des Bâtiments (EcoDynBat)

AGP

Role: Collaborator

Requérant(e)s: IGT

Financement: SUPSI; OFEN; EMPA; Viteos; Socle HEIG-VD Ra&D; Auto-fin IESE; Auto-fin IGT

Description du projet : Le projet EcoDynBat a pour objectif d'étudier l'effet de la variabilité temporelle lors du calcul des impacts environnementaux de l'électricité consommée dans les bâtiments. Ce travail tient compte des fluctuations temporelles 1) de la production électrique nationale, 2) des importations d'électricité, 3) des pertes réseaux et de conversions, 4) de la production d'électricité décentrali-sée et 5) de la demande d'électricité au sein du bâtiment.

Research team within HES-SO: Périsset Blaise , Duret Alexis , Citherlet Stéphane , Lasvaux Sébastien , Padey Pierryves , Capezzali Massimiliano , Jobard Xavier , Goulouti Kyriaki

Partenaires académiques: IESE; IGT

Partenaires professionnels: losinger; Amstein + Walthert

Durée du projet: 11.12.2018 - 28.08.2020

Montant global du projet: 101'630 CHF

Publications liées:

Dynamic Life Cycle Assessment of the building electricity demand : a case study

Statut: Completed

2020

Development and testing of novel applications for adsorption heat pumps and chillers

Scientific paper ArODES

Xavier Jobard, Pierryves Padey, Martin Guillaume, Alexis Duret, Daniel Pahud

Energies, 2020, vol. 13, no. 3, article no. 615

Link to the publication

Summary:

This work aims at the development and the experimental characterization of new applications for adsorption heat pumps and chillers driven by industrial waste heat or renewable sources that can provide heating and/or cooling. Adsorption technologies offer the advantage of providing heating and cooling from low temperature sources below 100 °C without using refrigerant with high Global Warming Potential and with very low electricity consumption. Therefore, the technology enables the use of large untapped heat sources, increasing the energy efficiency of the heating and cooling sector with very limited impact on the environment. Several applications were investigated numerically for Switzerland using a simplified model of an adsorption heat pump. Four scenarios were identified as interesting: (1) the valorization of low-grade industrial waste heat in district heating networks, (2) energy efficiency improvement of district heating substations, (3) an autonomous adsorption heat pump with a wood pellets burner and (4) cooling applications. These scenarios were experimentally validated with a laboratory test of a commercial silica gel/water machine. Results show that there is a gap of up to 40% between the prediction of the simplified model and the experimental results. Therefore, there is huge potential to improve the performances of this commercial unit for these applications.

2018

Evaluating the cost of heat for end users in ultra low temperature district heating networks with booster heat pumps

Scientific paper ArODES

Jacopo Vivian, Giuseppe Emmi, Angelo Zarrella, Xavier Jobard, Dirk Pietruschka, Michele De Carli

Energy, 2018, vol. 153, pp. 788-800

Link to the publication

Summary:

A promising district heating concept consists of distributing the heat at temperatures below 45 °C and using booster heat pumps at the customers' substations to provide the appropriate temperature needed for space heating and domestic hot water production. As such, thermal networks would be able to abate heat losses and substantially increase the number of recoverable heat sources. At the same time, the supply temperature from the booster heat pumps can be tailored to the building supplied instead of being based on the most critical consumer. This work investigates the performance of booster heat pumps assuming network supply temperatures in the range between 15 °C and 45 °C. The impact of supply and return temperature on the levelized cost of heat for different end users was assessed. The parametric study shows the importance of the nominal network temperature difference in the design phase of the system in order to reach a good trade-off between initial investment and operating costs. The economic analysis shows that the system is already competitive with individual gas boilers provided that a local low-temperature heat source can be recovered with minor marginal costs.

2019

Development of a vacuum insulated thermal energy storage for industrial applications

Conference ArODES

Sara Eicher, Martin Guillaume, Xavier Jobard, Jacques Bony, Vittorio G. Palmieri, Francesco Di Giamberardino, Stéphane Citherlet

Proceedings of the ISES Solar World Congress 2019 and IEA SHC International Conference on Solar Heating and Cooling for Buildings and Industry 2019

Link to the conference

Summary:

In this article the development of a high performance, double-wall vacuum insulated thermal energy storage for high temperature applications is presented. In this concept, the main heat losses of the tank are limited to radiation and to the thermal bridges present in the wall of the tank and fittings. This concept is well suited for high temperature applications such as those found in the industrial sector where storage energy losses are an important issue. Few studies on double wall evacuated tanks were found in the open literature and none employed a completely evacuated gap as proposed in this study. A structural analysis was performed to validate the proposed design and ensure conformity to high temperature applications. Preliminary heat transfer calculations assessed the impact of low emissivity coatings on the radiative heat transport in the evacuated gap. A numerical model of the container was developed and the thermal behaviour investigated under different operating conditions.

Solar thermal systems for the swiss pharmaceutical industry sector

Conference ArODES

Martin Guillaume, Guy Wagner, Xavier Jobard, Sara Eicher, Stéphane Citherlet

Proceedings of the ISES Solar World Congress 2019 and IEA SHC International Conference on Solar Heating and Cooling for Buildings and Industry 2019

Link to the conference

Summary:

This work focuses on the integration of solar thermal systems in the Swiss pharmaceutical industry to provide the thermal energy required by their processes. In a first step, an analysis of the heat demand in this sector is carried out with a review of the processes that can benefit from solar energy. To identify the barriers of the solar system integration and define adequate solutions, two case studies are considered. In these feasibility studies, the objective is to identify the possible integration points for a solar thermal system and determine their profitability. For this purpose, simulations are carried out using two different tools (Gain Buddy and Polysun) to determine the proportion of solar energy that can be recovered by the selected pharmaceutical processes.

2017

FLEXYNETS :

Conference ArODES

a new district heating network concept for higher renewable and waste heat share

Ilyes Ben Hassine, Xavier Jobard, Linn Laurberg Jensen

Proceedings of the ISES Solar World Congress 2017 and IEA SHC International Conference on Solar Heating and Cooling for Buildings and Industry 2017

Link to the conference

Summary:

The FLEXYNETS project on low-exergy district heating and cooling systems has been started in summer 2015 in the framework of the European H2020 program. The project aims to develop a new generation of intelligent district heating and cooling networks that reduce energy transportation losses by working at temperature levels lower than 40 °C. Reversible heat pumps and chillers are used at laboratory scale to exchange heat with the DHC network on the demand side. In this way, the same network can provide contemporary heating and cooling. FLEXYNETS solutions integrates effectively multiple generation sources (including high- and low-temperature solar thermal, biomass, cogeneration and waste heat) where they are available along the DHC network. Two network types are considered in simulation: the classic supply-return type and the single-pipe system. This paper describes possible operation strategies and some control aspects related to the second network type.

Smart control of a district heating network with high share of low temperature waste heat

Conference ArODES

Jacopo Vivian, Xavier Jobard, Johann L. Hurink

Proceedings of the 12th Conference on Sustainable Development of Energy, Water and Environmental Systems

Link to the conference

Summary:

An important research direction in the field of district heating and cooling (DHC) systems is to enhance the flexibility of the networks by increasing their capability to integrate different heat sources and sinks. Reducing the network temperature to adequate levels (below 40°C) and using reversible heat pumps reduces the heat losses and enables consumers to exchange heat with the network in both directions, thus becoming prosumers. Moreover, this concept unlocks the potential of low-grade, locally available heat sources such as waste heat. However, when the share of uncontrolled, decentralized heat supplied to the network is high, a suitable control system must be present to guarantee a correct hydraulic and thermal balance of the system. In the current paper, a low-temperature district heating system specifically designed for the south-west district of the Danish city of Aarhus, consisting of 22 aggregated consumers with an estimated peak load of 6 MW, is used as a case-study to investigate the integration of prosumers in heating networks. The main heat supply of the considered system consists of a CHP (gas-fired internal combustion engine) coupled with a hot water tank and of an auxiliary gas boiler. These units are owned and operated by the network manager. Additionally, two substations supply waste heat to the network; however, the network manager does not control them directly. To schedule the operation of its own supply stations, the network manager uses forecasts of heat load, waste heat availability and electricity prices. The goal is to minimize the cost of the overall heat generation mix of the DH system. This control problem is modelled as a mixed integer linear programming (MILP) optimization problem, which is solved in a rolling horizon scheme. An economic performance indicator is used to evaluate the performance of this advanced control method compared to a basic control based only on local feedbacks from the system.

2015

Entwicklung neuartiger PVT-Kollektoren :

Conference ArODES

Leistungsfähigkeit und Potenzialanalyse für verschiedene Klimazonen

Nansi Palla, Reiner Braun, Xavier Jobard, Irina Mitina, Jan Cremers, Ursula Eicker

7. Forum Bauwerkintegrierte Photovoltaik

Link to the conference

2014

Development of multivalent PV-thermal collectors for cooling, heating and generation of electricity

Conference ArODES

Nansi Palla, Reiner Braun, Xavier Jobard, Irina Mitina, Jan Cremers, Ursula Eicker

Sustainable habitat for developing societies] : [choosing the way forward : 30th International PLEA Conference proceedings

Link to the conference

Summary:

Growth of cities and rising occupant comfort expectations has led to an increasing cooling demand of buildings. The use of solar energy for the production of electricity with photovoltaic modules and hot water with solar collectors is a common application. Operating the PV-T collectors at night is the possibility given to cover the cooling demand with a renewable energy source; radiative cooling. This paper focuses on the potential analysis of PV-T collectors for heating, cooling and electricity production for 6 different climate conditions. First the state of the art, four different PV-T technologies and two examples for building integration are presented. This new prototypes of PV-T collectors with different joining methodologies between the absorber and the PV module have been developed and tested at an outdoor test stand under dynamic conditions. Measurements of these four new collector types are shown and compared with a TRNSYS PV-T collector model. Finally a potential analysis for heating, cooling and electricity production for one of the developed PV-T collector was carried out under different climatic conditions. The simulation results showed that this PV-T collector has the highest cooling potential in cold and moderate climate zones where cooling is needed only temporarily. In hot and humid climates where cooling is needed over the whole year, the cooling potential of the PV-T collector for radiative cooling is less. The increase of electricity production by cooling the PV cells varies between 0,1 and 5,8 %, depending on the inlet temperature and the weather conditions.

Performance analysis of uncovered PV-T collectors for radiative cooling and heating applications

Conference ArODES

Xavier Jobard, Reiner Braun, Nansi Palla, Ursula Eicker

Proceedings of the EuroSun 2014

Link to the conference

Summary:

New uncovered photovoltaic-thermal (PV-T) collectors were developed and tested to produce electricity, chilled and hot water. The use of uncovered PV-T collectors has already been investigated for heating applications. However uncovered PV-T collectors are also interesting for radiative cooling applications. This concept was already demonstrated in two plus energy houses that participated in the Solar Decathlon Europe competition. The working principle of radiative cooling is to use the radiative heat loss of the collector top surface to cool down a fluid which is then used to air-condition a building This paper focuses on the collector design characteristics and their performances for radiative cooling and heating applications. The procedure for the performance characterization is inspired from the quasi dynamic test method for uncovered thermal collector of the new EN ISO 9806:2014. For the identification of the collector parameters GenOpt has been coupled with TRNSYS. These coefficients are then used to establish the thermal efficiency curves for heating and cooling applications: the results of three different PV-T collector designs are compared between each other and to the performance of an uncovered solar collector.

2012

Development of a 5 kW cooling capacity ammonia-water absorption chiller for solar cooling applications

Conference ArODES

François Boudéhenn, Hélène Desmales, Joël Wyttenbach, Xavier Jobard, David Chèze, Philippe Papillon

Energy Procedia : Proceedings of the 1st International Conference on Solar Heating and Coolingfor Buildings and Industry (SHC 2012)

Link to the conference

Summary:

The development of a small capacity absorption chiller and the numerical and experimental results are presented in this paper. The prototype is a thermally driven ammonia-water absorption chiller of 5 kW cooling capacity for solar cooling applications. The chiller was developed in an industrial perspective with a goal of overall compactness and using commercially available components. In order to characterize various component technologies and different optimization components, the prototype is monitored with temperature, pressure and mass flow rate accurate sensors. The resulting chiller, characterized by a reduced load in ammonia-water solution and the use of brazed plate heat exchanger, has shown good performance during the preliminary tests. A comparison with the expected numerical results is given.

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Jobard Xavier

Chargé Ra&D HES

Main skills

Energétique du bâtiment

Energies renouvelables

Simulation thermique dynamique

Machine à sorption

Chargé Ra&D HES