Phase change material selection for two innovative compact energy storage systems in residential buildings

New conference paper released by University of Lleida at XI Congreso Nacional y II Internacional de Ingeniería Termodinámica

Within the framework of HYBUILD, an EU Horizon 2020-funded project, two innovative compact hybrid electrical/thermal storage systems for stand-alone and district connected residential buildings will be developed and tested in three demos located in Spain, France, and Cyprus. One of the innovative systems is aimed to be placed in buildings located in Mediterranean climate regions, where cooling loads are dominant, while the other system is intended for Continental climate regions, where the heating demand is dominant. Each system will include, among others components such as a sorption storage system and domestic hot water tanks, a latent thermal energy storage (LTES) system that will be connected to a heat pump through an innovative heat exchanger made of aluminium and filled with phase change material (PCM). In both cases, the heat pump works with electricity provided by a photovoltaic system that is, at the same time, connected to an electrical storage battery. The aim of using the LTES system is to enhance the use of solar energy, which will be translated into a reduction of the building energy consumption and related costs. This study focuses on the selection of the most suitable PCM to be used in each system. On the one hand, the LTES system of the Mediterranean system will be used to store cold to reduce the cooling demand. Taking into account that, according to the design parameters, the heat pump will require a refrigerant evaporation temperature around 2 oC, and the building cooling system will require water supply in the range from 7 oC to 12 oC, the PCM melting temperature range should be within 0 oC and 7 oC. On the other hand, the LTES system of the Continental system will be used to store heat to reduce the domestic hot water (DHW) demand. The LTES will be located at the compressor outlet and will be charged by the hot refrigerant that exits the compressor at temperatures as high as 120 oC. During the discharge process, the heat stored in the LTES will be supplied to the DHW at a temperature in the range between 50 oC to 55 oC. As a consequence, the range for the PCM melting temperature investigated in this case should be between 62 oC and 68 oC. Besides the melting temperature, other selection criteria considered include the PCM melting enthalpy and melting range, maximum allowed working temperature, density, thermal conductivity, availability, cost, and compatibility with aluminium. To decide the ideal PCM candidate for each system, a decision matrix was defined and used, by applying a weighted score to the selection criteria items according to their importance. The preliminary results indicate that for the Mediterranean system the best candidate is the commercial savE OM3 PCM, while for the Continental system, another commercial product PureTemp 63 is the most adequate option.

Read the full paper

Introducing FOSS | the Research Centre for Sustainable Energy of the University of Cyprus

HYBUILD is a group of 21 partners from 9 countries. Every month, a new HYBUILD partner is introduced in our Blog section. This month, the Research Centre for Sustainable Energy of the University of Cyprus.

The Research Centre for Sustainable Energy (FOSS) was created in order to play a key role in research and technological development activities in the field of sustainable energy within Cyprus and at international level with the aim of contributing to the achievement of the relevant energy and environment objectives set out by Europe. In particular, the FOSS strives to become a centre of excellence in energy that will act as a structure where world-standard R&D work can be performed, in terms of measurable scientific value (including training) and/or technological innovation. In FOSS significant research expertise from the University of Cyprus as well as from industry has been assembled that spans a wide range of fields: Electrical, Mechanical, Civil, Environmental, Chemical engineering, ICT, Physics, Chemistry, Economics, Finance, as well as Architecture. The FOSS team aims, with the development of the necessary synergies, to create the impetus for the advancement of the field of energy. Members of the Centre represent Cyprus in European Energy Committees such as the Energy Committee for the Horizon 2020, the SET Plan, the European Technology and Innovation Platform SNET and PV and the European Standards Committees on PV. Currently FOSS is a full member of DERlab, EUREC and EERA JP for SG. The researchers involved in the working team have extensive experience in grant proposal applications and have acquired funding for a range of research topics through the EU, the National Research Funding Agency in Cyprus as well as industry.

FOSS is heavily involved in all spheres of sustainable energy spreading from sources of energy, smoothly merging RES in the integrated solutions of the grid, development of enabling technologies such as storage and ICT that will facilitate the seamless merging of sustainable technologies in the energy system of tomorrow, the complete transformation of energy use by the effective introduction of sustainable alternatives in meeting the needs for mobility, heating and cooling and exploring ways of achieving even higher levels of efficiency in all areas of the economy.


In the framework of the HYBUILD project, FOSS Research Centre for Sustainable Energy, is responsible for system analysis and design, particularly for the Cyprus demo site, simulation activities and system integration. In addition, FOSS helps on the coordination of the Cyprus demo site activities in collaboration with the Municipality of Aglantzia and other partners. Furthermore, as a university institution, participates in the dissemination of the project and its results in international scientific journals and conferences.

HYBUILD Cyprus demo site (1/2)
HYBUILD Cyprus demo site (2/2)

Get in touch !

FOSS staff involved in HYBUILD are George E Georghiou, Venizelos Efthymiou, Aimilios Michael, Chryso Heracleous, Chrysanthos Charalambous.

George E Georghiou. Dr George E. Georghiou is the Director of FOSS Research Centre for Sustainable Energy and the leader of PV Technology, Department of Electrical and Computer Engineering, University of Cyprus. Prior to this, he was a University Lecturer and the undergraduate course leader in Electrical Engineering at the University of Southampton, and a Research Advisor for the Electricity Utilization, University of Cambridge. Having graduated from the University of Cambridge with a BA, MEng, MA (1996) all with distinction and a PhD (1999), Dr Georghiou continued his work at the University of Cambridge in the capacity of a Research Fellow (1999-2002). Dr Georghiou is currently a member of the Cyprus Energy Policy Council, the CENELEC and IEC committees on PV and is acting as an expert evaluator and reviewer for Horizon 2020 energy proposals as well as being a member of CIGRE and the European Solar Energy Industrial Initiative. He also represents Cyprus on the SET plan steering committee, the European Mirror Group on Photovoltaics and sits on the board of the Cyprus Energy Agency. Dr Georghiou has published over 300 papers in international journals and conference proceedings and his team has obtained research funding in excess of 10 million Euros from bodies such as the European Union, Industry (such as Honeywell, Q Cells, Tel-Solar, TSMC etc), Royal Society, Cambridge-MIT Institute, University of Cambridge, Research Promotion Foundation, Electricity Authority of Cyprus, Cyprus Energy Regulatory Authority etc. Amongst his scholarly achievements, are five outstanding paper awards for the most significant technical scientific contributions and an innovation prize.

Venizelos Efthymiou. Dr Venizelos Efthymiou from Cyprus is a holder of the UMIST university degrees: BSc in Electrical Engineering and Electronics, Master of Science (MSc) in Power Systems and Doctor of Philosophy (PhD). He worked for the Electricity Authority of Cyprus from March 1979 up to November 2013 and he left the Company from the post of Executive Manager Networks and from the post of Manager of the Distribution System Operator of Cyprus. He is a member of the Steering Committee of the European Technology and Innovation Platform of SNET, a member of the Steering Committee of PV Technology and Innovation Platform, a member of the DSO Committee of EURELECTRIC, chairman of the Research Centre FOSS of the University of Cyprus and chairman of CIGRE Cyprus.

Aimilios Michael. Architect Engineer Dipl.Arch.Eng., M.Sc., Ph.D., is an Assistant Professor in the Department of Architecture at the University of Cyprus, Director of Energy & Environmental Design of Buildings Research Laboratory (E&EDB) and member steering committee of the Inter-departmental Master Programme, Energy Technology and Sustainable Design of the Faculty of Engineering of the University of Cyprus. Aimilios Michael currently holds the position of Vice-President of the Council for Planning Derogation Applications, Ministerial Council Appointment. He is also member of the Board Council of the Scientific Technical Chamber of Cyprus, CSTC. Aimilios holds a PhD in Environmental Design and Energy in Architecture from the Department of Architectural Technology, School of Architecture, National Technical University of Athens, NTUA. During his studies, he was awarded numerous academic performance distinctions, including the Academic Excellence NTUA Award 2004, NTUA Silver Medal 2004 (1st rank), Best Design Diploma Thesis NTUA Award 2004 and Nomination for Best Doctoral Dissertation Award NTUA 2011. His research activities take on an interdisciplinary perspective and they focus on the areas of Energy and Environmental Design of Buildings and Advanced Architectural Technology. He participated as principal investigator and/or project coordinator in several funded research programmes. His architectural work -placing emphasis on energy and environmental architecture- has won awards (16) in architectural European and international competitions, including 1st prizes (2), and was presented in several architectural exhibitions in Cyprus and abroad. His research work has been published in books, refereed journals and conference proceedings.

Chryso Heracleous. Chryso Heracleous is a research fellow, seasonal lecturer and PhD candidate in the Department of Architecture of the University of Cyprus. She holds a bachelor’s degree in Architecture Engineering from the Technical School of the University of Patras, a Master’s in Environmental Design from the University of Bath (UK), and she is Certified Passivhaus Designer from the Passivhaus Institut, Germany. Her research interest focuses on the fields of Architectural Building Technology, Environmental Design and Energy Performance of Buildings with main purpose energy saving and improvement of human comfort, health and productivity. Since 2013, she participated as researcher in several research programmes funded by the European Commission, Directorate General for Research & Innovation, Research Promotion Foundation IPE-RPF and published her scientific work in some international conferences and scientific journals.

Chrysanthos Charalambous. Chrysanthos Charalambous was born in Cyprus on July 11, 1989. He received the bachelor’s degree and the MSc degree in Electrical and Computer Engineering from the Democritus University of Thrace, Xanthi, Greece, in 2014 and 2016, respectively. Now he is student of PhD in Electrical Engineering at University of Cyprus since January 2018, and special scientist at FOSS Research Center for Sustainable Energy. His research interests include power systems, renewable energy, smart grids, DC and hybrid DC-AC power systems, and distributed energy resources. Since 2017, he participated as a researcher in several research programmes funded by the European Commission, and Research Promotion Foundation IPE-RPF. In addition he has successfully attended the KNX course for smart home and building automation solutions.

XI National and II International Engineering Thermodynamics Congress

HYBUILD technical coordinator University of Lleida contributed to the XI National and II International Engineering Thermodynamics Congress which took place in Albacete, Spain.

This congress organised every 2 years is a unique meeting point for different university lecturers and professors, researchers, and professionals who develop activities in the field of engineering thermodynamics. Building on the outcomes of the previous edition held in 2017, this year’ edition of the congress encompassed an international dimension to allow the attendance of participants from all over the world to exchange experiences that improve the level of teaching, research and industry in the different fields where the engineering thermodynamics plays an important role.

The conference hosted more than 170 participants. HYBUILD was showcased at the Europe corner and an oral presentation of the project was given. Several young researchers from different Spanish universities were interested in receiving more details regarding the two systems developed within HYBUILD. A brief description of the project and the PCM selection methodology for both latent storages was explained in the oral presentation by Gabriel Zsembinszki, (University of Lleida). Acknowledgements to HYBUILD and European Commission support were shown at the end of the presentation.




Sun & thermal energy workshop | SP19 in Cagliari

Sun and thermal energy: Europe’s precious energy sources for efficient industries and buildings | Sustainable Places 2019, Cagliari, 05-07 June 2019

Keywords: solar, thermal, renewables, energy efficient buildings, industry, heat pumps

In this workshop, we discussed the progress of five Horizon 2020 projects – HYCOOL, SHIP2FAIR, THERMOSS, SUNHORIZON and HYBUILD – all implementing solar thermal and renewable technologies for buildings and for the industrial sector. The discussion offered opportunities to identify and benchmark key challenges being faced by the projects, both technical and non-technical, and allowed to identify cooperation opportunities.

Key innovative aspects:

  • The main goal and innovative aspect of SHIP2FAIR is to foster the integration of solar heat in industrial processes from the agro–food sector.
  • SunHorizon aims to develop heat pump solutions that will act properly coupled with advanced solar panels providing heating and cooling both for residential and tertiary buildings.
  • THERMOSS ensures an efficient match between supply and demand of energy through real- time management of thermal energy and by retrofitting through advanced heating and cooling technologies, leading to up to 30% savings in energy consumption.
  • HYCOOL’s mission is increasing the use of solar heat in industry processes, by coupling of a new Fresnel CSP Solar thermal collectors (FCSP) with specially build Hybrid Heat Pumps.
  • HYBUILD combines a compact sorption storage, a high-density latent storage, and an efficient electric storage in residential buildings.

Interactive discussion

The 5 projects discussed the following common horizontal issues :

  • Highest technological challenges faced by the projects
  • How digitalization and monitoring data can facilitate the promotion of the technologies of the projects
  • How to increase social acceptance of projects’ technologies, and main non-technological barriers
  • Key measures to achieve cost-reduction of projects’ technologies

Presentations and pictures of the workshop are available at this link.

Full workshop report

HYBUILD at CATE 2019 – Comfort at the Extremes: Energy, Economy and Climate

HYBUILD partner University of Cyprus – FOSS Research Centre for Sustainable Energy – Chryso Heracleous – presented a paper at CATE 2019 – Comfort at the Extremes: Energy, Economy and Climate Conference.

In the face of an ever more extreme climate the world is calling urgently for answers to questions of how people can stay not only comfortable, but also thermally safe and healthy in a warming world. Current and future temperature trends and events threaten not only buildings, settlements and cities but also the temporary settlements built to cope them such as transient populations.

CATE 2019 gathered leading international figures from many fields to discuss crucial questions and ways forward on how to best provide Comfort at the Extremes.

Read the full paper and download the presentation.

Conference proceedings available here.

CATE 2019 conference attendees
CATE 2019 session
Dr.Evangelia Topriska, Heriot Watt University, Dubai

HYBUILD presented at Eurotherm seminar #112 – Advanced Thermal Energy Storage

The Eurotherm seminar #112 – organised at the University of Lleida – did bring together researchers and practitioners from academia and industry, who are working in the rapidly-expanding field of thermal energy storage.

Eurotherm 2019 conference at University of Lleida

The most recent trends in areas such as novel storage materials, advanced storage concepts and configurations, thermal energy storage for renewable energy systems, and thermal energy storage in buildings were presented. This conference provided a forum for discussion among academics, researchers, and professionals who work in the field of thermal energy storage.

The event gathered more than 130 attendees.

HYBUILD presentation by partner AIT at Eurotherm

At the European exhibition corner, some participants were interested in receiving more details regarding the two systems developed within HYBUILD.  HYBUILD partners presented some intermediate technical outcomes of the project by means of either oral presentation or posters. Useful feedback was received from experts in the topic.

European Exhibition corner at Eurotherm featuring HYBUILD posters

Introducing the Institute for Renewable Energy of Eurac Research

HYBUILD is a group of 21 partners from 9 countries. Every month, a new HYBUILD partner is introduced in our Blog section. This month, the Institute for Renewable Energy of Eurac Research.

The Institute for Renewable Energy conducts cutting-edge applied research on how to produce energy using sustainable sources, manage energy systems and reduce energy consumption. Its activities include national and international research projects, as well as direct cooperation with industry partners. Industry-related projects involve the development of innovative products and the evaluation of technological energy saving solutions.​ The Institute has more than 100 collaborators, 5 research groups and an infrastructure of 6 indoor and 2 outdoor laboratories (one still in construction opening within 2019) in the fields of technology, efficient building systems and solar energy. The laboratoriesare a contact point between scientific research and industrial partners interested in testing and implementing innovative energy technologies. The services offered include laboratory testing on single components and integrated energy systems, monitoring of applied demonstration sites, experimental outdoor installations as well as dynamic simulation and optimisation of energy systems.

In every project, our researchers use simulations, experimental tests and creation of prototypes to turn an innovative concept into a concrete project.

The Institute offers support also in the elaboration of complex energy models as decision support system for single energy systems or buildings as well as for urban and regional areas.​​

The role of Eurac Research in Hybuild

Eurac Research is the main partner in charge of the models and simulations for the Mediterranean and Continental Hybuild energy systems and buildings. Energy models of demo and reference buildings, heating and cooling systems and hybrid storages will be developed and simulated for: i) evaluating the proof of concept through the KPIs identified in the project, ii) computing the LCA and LCC analysis and iii) testing the developed control strategies. Once the systems will be installed in the demo-cases, the models developed by Eurac Research will be validated through measurements data to have a benchmark for the performance of the running systems. Both Mediterranean and Continental concepts will be also simulated in identified reference buildings overall Europe in order to demonstrate the replicability of the Hybuild systems.

Get in touch !

Grazia Barchi is a senior researcher in the group of photovoltaic energy system at Eurac Research, Institute for Renewable Energy, Bolzano.

She is responsible for the PV integration topic and her research mainly focuses on electric grid modelling and operations, electrical storage and advanced measurements technique for smart grids. She received the Ph.D. degree in Information and Communication Technology at the University of Trento, Italy, in 2015 and the M.Sc. degree in electronic engineering from the University of Perugia, Italy, in 2011. She was visiting research at University of Applied Science and Art Western Switzerland in 2011 and at University of California Berkeley in 2014.

Mattia Dallapiccola is a researcher at Eurac Research, Institute for Renewable Energy, Bolzano.

His research focuses on modelling of photovoltaic system, BIPV, partial shading of photovoltaic system and electrical and thermal energy storage. He obtained a master degree in Energy Engineering at the University of Trento – Free University of Bolzano in 2018.

Chiara Dipasquale is a Senior Researcher at the Institute for Renewable Energy at Eurac Research, Italy.

Expert in dynamic simulations of buildings and sustainable heating and cooling systems; development of control strategies for heating and cooling systems; definition of retrofit solutions for existing buildings.

Federico Trentin received a MSc in Energy Engineering at the University of Trento – Free University of Bolzano in 2018.

After graduating he joined as researcher the Sustainable Heating and Cooling Systems research group at the Institute for Renewable Energy. He works mainly on dynamic simulation and control of innovative HVAC systems.

Sustainable Places 2019 Draft Agenda released

The draft agenda of Sustainable Places 2019 has just been released.

Join our “Sun and thermal energy: Europe’s precious energy sources for efficient industries and buildings” workshop on June 6th, co-hosted by HYBUILD, SunHorizon, HYCOOL, SHIP2FAIR and THERMOSS.

Register at

HYBUILD at Sustainable Places 2019 in Cagliari | 5-7 June

HYBUILD is co-organising a a workshop at Sustainable Places 2019, 5-7 June, Cagliari (Italy).

The workshop is entitled Sun and ambient heat: Europe’s precious energy sources for efficient industries and buildings. It will present the technological systems of five H2020 projects: HYCOOL, SHIP2FAIR, THERMOSS, SUNHORIZON and HYBUILD; each implementing renewable energy solutions to conserve energy and improve thermal comfort for both the residential and industrial sectors. The workshop is also supported by EHPA (European Heat Pumps Association) and ESTTP (European Solar Thermal Technology Panel).

Register to Sustainable Places at :

HYBUILD journal paper released : Hybrid Adsorption-Compression Systems for Air Conditioning in Efficient Buildings: Design through Validated Dynamic Models

Hybrid sorption-compression systems are gaining interest for heating/cooling/ refrigeration purposes in different applications, since they allow exploiting the benefits of both technologies and a better utilization of renewable sources. However, design of such components is still difficult, due to the intrinsic complexity of the systems and the lack of reliable models. In particular, the combination of adsorption-compression cascade unit has not been widely explored yet and there are no simulations or sizing tools reported in the literature. In this context, the present paper describes a model of a hybrid adsorption-compression system, realised in Modelica language using the commercial software Dymola. The models of the main components of the sorption and vapour compression unit are described in details and their validation presented. In addition, the integrated model is used for proving the feasibility of the system under dynamic realistic conditions and an example of the technical sizing that the model is able to accomplish is given.

Read the full paper at :