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Eicher Sara

Chargée de Ra&D HES

Main skills

Technologies environnementales

Computational Fluid Dynamics (CFD)

Chargée de Ra&D HES

Phone: +41 24 557 73 51

Desktop: S05a

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

Dr Sara Eicher is a mechanical engineer with a strong specialisation in thermal engineering and energy systems. She holds a PhD from the University of South Wales (UK), where she carried out research on the modelling and control of gas-fired furnaces. Her academic path includes international teaching experience in Portugal, the UK, and Switzerland.

Since 2007, she has been working at the Institute of Energy at HEIG-VD in Yverdon-les-Bains, where she leads and coordinates applied R&D projects focusing on renewable thermal energy, energy efficiency, and the decarbonisation of industrial processes. She is also actively involved in national energy programmes such as the Innovation Booster Energy Lab, where she supports start-ups, SMEs, and institutions in the development of innovative energy solutions.

From 2005 to 2007, Dr Eicher worked at CERN (European Organisation for Nuclear Research) in Geneva as CFD Team Coordinator within the Detector Cooling Section. There, she was responsible for the planning, development, and management of computational fluid dynamics projects, as well as the coordination and training of the internal CFD team.

Alongside her research and technical roles, Dr Eicher plays a key role in education. She designs and delivers courses and modules at Bachelor, Master (MSE), and continuing education levels, covering topics such as solar thermal systems, renewable energy, and airflow simulation in buildings.

Her work is characterised by a strong interdisciplinary approach, bridging engineering, applied research, and practical implementation within the broader context of the energy transition.

Dr. Eicher is an active member of the Swissolar Solar Thermal Commission.

MSc HES-SO en Engineering - HES-SO Master

Energie solaire

BSc HES-SO en Energie et techniques environnementales - Haute école d'Ingénierie et de Gestion du Canton de Vaud

Energies Renouvelables
Simulation CFD

Ongoing

OFEN - DrainProof

AGP

Role: Main Applicant

Financement: HES-SO Rectorat

Description du projet : OFEN - DrainProof

Research team within HES-SO: Eicher Sara , Pauletta Stefano

Partenaires académiques: iE

Durée du projet: 26.05.2023 - 31.12.2025

Montant global du projet: 13'483 CHF

Statut: Ongoing

Completed

SOLIND2SERVICE

Role: Collaborator

Financement: CANTON VD

Description du projet :

Solar Process Heat in the Swiss Service Sectors

Research team within HES-SO: Eicher Sara

Durée du projet: - 31.12.2022

Statut: Completed

SIMPLYDRAIN

Role: Collaborator

Financement: BFE

Description du projet :

Solar Thermal Concepts for DHW Systems in MFH

Research team within HES-SO: Eicher Sara

Durée du projet: - 31.12.2021

Statut: Completed

VITES

Role: Collaborator

Financement: BFE

Description du projet :

Vacuum Insulated Thermal Energy Storage

Research team within HES-SO: Eicher Sara

Durée du projet: - 31.12.2019

Statut: Completed

SOLIND

Role: Collaborator

Financement: SUISSENERGIE

Description du projet :

Solar Process Heat in the Swiss Industry and

Research team within HES-SO: Eicher Sara

Durée du projet: - 31.12.2018

Statut: Completed

DRAINBIS

Role: Collaborator

Financement: BFE

Description du projet :

Drainback solar thermal systems in Switzerland

Research team within HES-SO: Eicher Sara

Durée du projet: - 31.12.2018

Statut: Completed

Projet COLAS Pittet-Chatelan Extension

AGP

Role: Collaborator

Requérant(e)s: IGT, Duret Alexis, IGT

Financement: OFEN; Socle VD Ra&D; COLAS Suisse, SA

Description du projet : Pour la première fois au niveau mondial, Colas Suisse SA a mis en place une installation solaire thermique haute température permettant à la fois de produire de la chaleur pour maintenir deux cuves de bitume au-dessus de la température de fusion et pour chauffer un bâtiment. Le système déployé offre en outre la possibilité de stocker la chaleur excédentaire à deux niveaux de température différents soit dans une cuve remplie d'eau (40-90°C) ou dans les deux cuves de stockage de bitume (110-200°C). L'installation solaire devrait à terme permettre de couvrir 60% des besoins énergétiques annuels du centre de travaux d'Yverdon-les-Bains. Les objectifs du projet proposé sont les suivants : 1. Mesurer les performances thermiques et économiques de l'installation solaire thermique sur site. 2. Modéliser sur Polysun l'installation solaire thermique afin de simuler son niveau de performance sous d'autres climats (y compris validation expérimentale du modèle). 3. Optimiser le fonctionnement de l'installation d'un point de vue thermique, économique et environnemental (écobilan).

Research team within HES-SO: Bunea Mircea Stefan , Garin Isabelle , Duret Alexis , Loperetti Murielle , Citherlet Stéphane , Bony Jacques , Eicher Sara , Weber Nicolas

Partenaires académiques: IGT; Leiter SPF Research, HSR; Duret Alexis, IGT

Durée du projet: 01.10.2014 - 31.12.2018

Montant global du projet: 373'408 CHF

Statut: Completed

IMPROVE - Une meilleure information pour les consommateurs d'énergie pour plus d'économie d'énergie

AGP

Role: Collaborator

Requérant(e)s: IGT, Citherlet Stéphane, IGT

Financement: OFEN; SUPSI ; ZHAW; Socle Ra&D; FHNW

Description du projet : Une des clés pour la diminution de la consommation d'énergie passera par une meilleure information des consommateurs. Le projet IMPROVE vise à réduire le gap entre l'information à disposition des fournisseurs d'énergie concernant la consommation de leurs clients, et l'information à disposition de ces derniers. Une analyse des modèles existants sera effectuée et un modèle minimal d'information sera défini et présenté aux fournisseurs d'énergie. Le projet sera effectué par un groupe de recherche de quatre hautes écoles Suisses.

Research team within HES-SO: Loperetti Murielle , Citherlet Stéphane , Bony Jacques , Favre Didier , Padey Pierryves , Eicher Sara

Partenaires académiques: IGT; Citherlet Stéphane, IGT

Durée du projet: 01.11.2016 - 30.11.2018

Montant global du projet: 240'274 CHF

Statut: Completed

Bâti-Tech - Face InTec: Développement d'un élément de façade à haute performance trifonctionnel

AGP

Role: Collaborator

Requérant(e)s: Lesbat

Financement: Socle VD Ra&D; Dir. générale de l'env. de l'état de Vaud (DGE)

Description du projet : L'objectif du volet 1 du projet Bâti-Tech est de modifier l'élément de façade Face InTec existant afin d'y ajouter la fonction "captage thermique" de l'énergie solaire reçue.

Research team within HES-SO: Bunea Mircea Stefan , Duret Alexis , Citherlet Stéphane , Bony Jacques , Affolter Jean-François , Favre Didier , Eicher Sara , Morey Philippe

Partenaires académiques: Lesbat; IESE

Partenaires professionnels: Alpiq InTec Romandie SA

Durée du projet: 01.07.2013 - 31.05.2017

Montant global du projet: 28'122 CHF

Statut: Completed

Bâti-Tech - Histosol: Optimisation d'une nouvelle génération de collecteurs solaires invisibles

AGP

Role: Collaborator

Requérant(e)s: Lesbat

Financement: Socle VD Ra&D; Dir. générale de l'env. de l'état de Vaud (DGE)

Description du projet : L'objectif de ce deuxième volet du projet Bâti-Tech est d'optimiser et de réduire les coûts des collecteurs solaires Histosol. La réflexion se focalisera sur le transfert de chaleur entre la surface extérieure de la toiture et le collecteur de chaleur.

Research team within HES-SO: Bunea Mircea Stefan , Duret Alexis , Citherlet Stéphane , Bony Jacques , Favre Didier , Eicher Sara

Partenaires académiques: Lesbat

Durée du projet: 01.07.2013 - 31.12.2015

Montant global du projet: 395'450 CHF

Statut: Completed

2015

Mathematical modelling of unglazed solar collectors under extreme operating conditions

Scientific paper ArODES

Mircea Bunea, Bengt Peres, Sara Eicher, Catherine Hildbrand, Jacques Bony, Stéphane Citherlet

Solar Energy, 2015, vol. 118, pp. 547-561

Link to the publication

Summary:

Combined heat pumps and solar collectors got a renewed interest on the heating system market worldwide. Connected to the heat pump evaporator, unglazed solar collectors can considerably increase their efficiency, but they also raise the coefficient of performance of the heat pump with higher average temperature levels at the evaporator. Simulation of these systems requires a collector model that can take into account operation at very low temperatures (below freezing) and under various weather conditions, particularly operation without solar irradiation. A solar collector mathematical model is developed and evaluated considering, the condensation/frost effect and rain heat gains or losses. Also wind speed and long wave irradiation on both sides of the collector are treated. Results show important heat gains for unglazed solar collectors without solar irradiation. Up to 50% of additional heat gain was found due to the condensation phenomenon and up to 40% due to frost under no solar irradiation. This work also points out the influence of the operating conditions on the collector’s characteristics. Based on experiments carried out at a test facility, every heat flux on the absorber was separately evaluated so that this model can represent a valuable tool in optimising the design or the thermal efficiency of the collector. It also enables the prediction of the total energy yield for solar thermal collectors under extreme operating conditions.

2012

Solar assisted heat pump for domestic hot water production

Scientific paper ArODES

Sara Eicher, Catherine Hildbrand, Jacques Bony, Mircea Bunea, Jean-Christophe Hadorn, Stéphane Citherlet

Energy Procedia, 2012, vol. 30, pp. 571-579

Link to the publication

Summary:

In this article, a R&D project is described involving a prototype solar assisted heat pump (HP) designed for domestic hot water preparation for single family dwellings. This project, developed within the framework of Task 44 of the IEA Solar and Cooling Programme, uses solar energy on the HP evaporator side to maximize the performance level of the system. In cases where solar energy is not enough, the HP under investigation has been designed to extract energy from the heating circuit of the building. This study involves both test bench measurements and dynamic simulations of the solar assisted heat pump system. The overall objectives of the project are summarised as follows: • Development of solar thermal technology • Improvement of HP performance for DHW production • Reduction of non-renewable energy consumption • Reduction of environmental impacts This article presents an overview of the project and its current status.

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.

2018

How to improve energy building information to induce energy savings ? :

Conference ArODES

insights from Switzerland

Uros Tomic, Vicente Carabias-Hütter, Tobias Kuehn, Francesca Cellina, Roberta Castri, Nikolett Kovacs, Stéphane Citherlet, Sara Eicher, Pierryves Padey, Bastian Burger, Jürg Bichsel

Proceedings of BEHAVE 2018, 5th European Confernece on Behaviour and Energy Efficiency, 6-7 September 2018, Zurich, Switzerland

Link to the conference

Drainback solar thermal systems in Switzerland :

Conference ArODES

market overview and main barriers

Sara Eicher, Mircea Bunea, Martin Guillaume, Jacques Bony, Stéphane Citherlet

Proceedings of EuroSun 2018, 10-13 September 2018, Rapperswill, Switzerland

Link to the conference

Summary:

During the last years, solar thermal systems have lost in attractiveness mostly due to their high initial installation costs, higher complexity compared to photovoltaic systems and a regular need of maintenance to avoid overheating and freezing problems, e.g. control of glycol mixture properties. Drainback (DB) solar thermal systems may overcome some of these issues and contribute to the market recovery as it prevents overheating and freezing of the solar system components even when pure water is used as the heat carrier fluid. It also needs less components than classical pressurised systems, which leads to less complex, lower system costs. Nevertheless, this type of system has not been very successful in Switzerland, only accounting for a small part of the market. In order to identify the barriers preventing the wide Swiss acceptance of DB systems, a literature review was performed and an online survey conducted and addressed to the different actors of the solar thermal sector. The aim is to understand the reasons of low market penetration of DB systems in Switzerland and to clearly identify the main barriers to its spreading. Results show that investments in research, product development, technology demonstration and market deployment in the form of professional training and technology information are essential to promote the DB in Switzerland.

2017

Medium temperature solar thermal installation for industrial thermal storage of bituminous products

Conference ArODES

Mircea Bunea, Catherine Hildbrand, Sara Eicher, Alexis Duret, Stéphane Citherlet

Proceedings of SES Solar World Congress 2017, 29 Oct.-2 Nov. 2017, Abu Dhabi, UAE

Link to the conference

Summary:

In this article, the performance analysis of a medium-temperature solar thermal installation integrated at the Colas Suisse SA industrial site in Yverdon-les-Bains (CH) is presented. The innovative collector system supplies energy for the temperature maintenance of bituminous products and provides part of the heating needs of the administrative building in the industrial site. The initial objective of Colas Suisse SA was to cover approximately 60% of the thermal energy demand of the site with solar energy. Field measurements provided an insight into the overall operation of the installation during 2015 to 2017. Despite improvement of the system, the performance of the collector field both in terms of energy and financial aspects was found below the expected values. On the other hand, simulations have shown the potential for improvement offered by the current installation. Despite nonoptimal operation of the solar installation, a life cycle impact assessment have indicated interesting potential primary energy savings and greenhouse gas reductions.

2016

Étude détaillée d'une rénovation à haute performance énergétique d'un bâtiment multifamilial

Conference ArODES

Jacques Bony, Didier Favre, Sébastien Lasvaux, Blaise Périsset, Catherine Hildbrand, Sara Eicher, Stéphane Citherlet

Proceedings of 19. Status-Seminar « Forschen für den Bau im Kontext von Energie und Umwelt »

Link to the conference

Summary:

Cet article s’inscrit dans le projet ECO-Reno "Rénovation à faible impacts environnementaux dans le domaine de l’habitation" et présente une évaluation des impacts environnementaux et des coûts liés à la rénovation énergétique d’un bâtiment d'habitation de 59 appartements. L'analyse de cycle de vie montre des résultats très positifs quel que soit l'indicateur environnemental considéré (CEDNRE, GWP et UBP). La part des matériaux utilisés dans la rénovation reste faible en comparaison des économies d'énergie réalisées. Les aspects financiers ont mis en évidence la grande influence de l’évolution du prix de l'énergie sur le nombre d'années nécessaire pour le remboursement des investissements. Dans le cas de ce bâtiment, ce remboursement via les économies d’énergie parait difficile à l'échelle du temps des constructions actuelles. Cependant, une répercussion des coûts de rénovation a été effectuée sur les loyers et permet d'envisager l’exploitation financière de ce bâtiment sereinement.

2015

Analysis of a medium temperature solar thermal installation with heat storage for industrial applications

Conference ArODES

Mircea Bunea, Catherine Hildbrand, Alexis Duret, Sara Eicher, Lionel Péclat, Stéphane Citherlet

Energy Procedia ; Proceedings of the 4th International Conference on Solar Heating and Cooling for Buildings and Industry (SHC 2015), 2-4 December 2015, Istanbul, Turkey

Link to the conference

Summary:

Willing to be an active participant to the Swiss strategy for sustainable development, Colas Switzerland SA, has decided to integrate a solar thermal installation in one of its bitumen storage industrial site. Situated in Yverdon-les-Bains (Switzerland), the solar installation aims to provide up to 60% of the thermal energy demand of the site. Coupled with a gas boiler, the solar collectors were designed to meet the energy needs of an onsite building, and to ensure constant temperature of a bitumen tank and two emulsions tanks (mixture of bitumen and water). In order to analyse and optimise the thermo-economic and environmental efficiency of this installation, a R&D project funded by the Swiss Federal Office of Energy was launched in 2014. This article gives an overview of the project objectives and describes the solar thermal installation and its operating modes. It also presents the numerical model and the first experimental results. First observations have revealed a thermal installation operating well behind its expected targets. Typically, the solar collector efficiency at temperatures above 200 °C is 50% lower than expected since it is operating under non-optimal conditions. Some technical dysfunctions have also been detected in the control system of one of the storage tanks. Consequently, a thorough evaluation of the operation of the installation was conducted to identify any other anomalies. In parallel to this work, the numerical model of the installation was developed and is currently under validation against the ongoing experimental measurements. Preliminary simulations of the installation in its current state have showed a solar yield nearly 2 times lower than expected, confirming the existence of anomalies in the running of the installation.

Development of a high performance facade element

Conference ArODES

Sara Eicher, Jacques Bony, Alexandre Duret, Mircea Bunea, Stéphane Citherlet

Proceedings of CISBAT 2015 - Cleantech for Smart Cities Buildings - From Nano to Urban Scale, 9-11 September 2015, Lausanne, Switzerland

Link to the conference

Summary:

This paper presents an overview of the R&D activities for the Bâti-Tech project that concerns integration of solar thermal collectors into an existing, commercialised multifunctional facade element. The study involves both monitoring and test bench measurements along with dynamic simulations of the facade element integrated in a building. The existing facade concept includes thermal and acoustic insulation and PV production. The overall objective of the project is to modify the current facade element and integrate a solar thermal collecting function for building heating purposes. This project, funded by the Canton of Vaud, was launched at the end of 2013 within the framework of its "100 millions pour les énergies renouvelables et l’efficacité énergétique" programme. Research has indicated that the PV performance of the investigated facade is greatly affected by shading of the near surrounding. Measured stagnation temperatures of the PV panel of the facade element have also shown a limited potential for using heat from these modules for heating applications unless combined with a heat pump. Simulations have further suggested that the use of flat plate systems as a collecting device integrated in the building envelope could be interesting for space heating and domestic hot water preparation. The study is now focusing on the modification and integration of a solar thermal collector into the existing facade concept.

2013

Life cycle impact assessment of a solar assisted heat pump for domestic hot water production and space heating

Conference ArODES

Sara Eicher, Catherine Hildbrand, Annelore Kleijer, Jacques Bony, Mircea Bunea, Stéphane Citherlet

Energy Procedia ; Proceedings of the 2nd International Conference on Solar Heating and Cooling for Buildings and Industry (SHC 2013), 23-25 September 2013, Freiburg, Germany

Link to the conference

Summary:

Solar heat pumps (SHP) are a class of heating systems combining solar thermal technology with heat pumps. In this article the life cycle impact assessment (LCIA) of a SHP system used to produce domestic hot water (DHW) and space heating (SH) for single family dwellings is presented. This study intends to evaluate the environmental impacts of the energy and material used in a serial SHP installation and identify areas for improvement by applying a “cradle-to-grave” approach when analysing the system. This includes the installation materials both in their manufacturing and disposal phases as well as the energy consumption for DHW and SH throughout a service life of 20 years. In addition, it provides a comparison against two other residential heating systems operating with the same life expectancy. In this LCIA, two environmental related indicators are used, one associated with depletion of non-renewable energy resources (CEDNRE) and the other with climate change (GWP). The impact of the type of electricity used was also investigated by defining, in addition to the European supply mix, an alternative supply mix with electricity deriving from renewable sources. This study shows that SHP have lower environmental impacts than systems operating on electricity only. Installations with large solar collector surfaces are also seen to lead to lower energy consumption related impacts. If the electricity used by these systems derives from renewable sources, the environmental performance improves. However, under these conditions, the SHP impact (material and energy consumption) related to climate change will be of the same order as that of the electric system due to a higher contribution of the infrastructure content of these systems.

Achievements

PEOPLE@HES-SO
Directory and Skills inventory

Eicher Sara

Chargée de Ra&D HES

Main skills

Solaire thermique

Energies renouvelables

Technologies environnementales

Thermal engineering

Energy modelling

Computational Fluid Dynamics (CFD)

Transfert de chaleur

Chargée de Ra&D HES

PEOPLE@HES-SO Directory and Skills inventory

Eicher Sara

Chargée de Ra&D HES

Main skills

Solaire thermique

Energies renouvelables

Technologies environnementales

Thermal engineering

Energy modelling

Computational Fluid Dynamics (CFD)

Transfert de chaleur

Chargée de Ra&D HES

PEOPLE@HES-SO
Directory and Skills inventory