From Swiss Federal Institute of Technology in Lausanne [EPFL-École Polytechnique Fédérale de Lausanne] (CH): “A heating plant that combines renewable energy sources”

From Swiss Federal Institute of Technology in Lausanne [EPFL-École Polytechnique Fédérale de Lausanne] (CH)

Emmanuelle Marendaz Colle

EPFL has recently brought an innovative heating plant online and will soon connect it to a large data center. The plant will help the Ecublens campus optimize how it generates and consumes energy, with the goal of achieving carbon neutrality.

Seen from the metro, the new structure’s design is quite striking: red blocks clad entirely in solar panels. In reality, this is merely the visible portion of a vast underground network that extends from Lake Geneva to the campus’s Innovation Park. Opened this year, EPFL’s new heat-pump-powered plant stands out for its aesthetic appeal, innovative approach and energy-saving performance. It will be presented as part of CISBAT 2021, a conference focusing on the energy and environmental efficiency of the built environment, to be held at EPFL from 8 to 10 September.

Adjacent to the building are two chimneys connected to gas boilers. These provided heat to the EPFL campus for two years while the plant was under construction. In the future, they will be used only in the case of a system failure. “The new plant was put to the test one weekend this past February, when the temperature fell below freezing. It passed with flying colors,” says Pascal Gebhard, who is part of the Infrastructure group within the Vice Presidency for Operations (VPO). With his colleagues from the construction and operations teams, he has been overseeing the project since it got underway in 2014, and particularly since 2019, when the old heating plant was demolished.

Before construction on the new plant got underway, the campus buildings had been using lake water in their heating system since 1985. EPFL has actually been a trailblazer in this field since the late 1970s, when it built its first pumping station for cooling purposes. But during that time, two oil-fired turbines were used to supplement heating needs, particularly following an increase in the number of buildings on campus.

An innovative solution

When it came time to upgrade the outdated heating plant, EPFL’s Sustainability Unit – and in particular its former head Philippe Vollichard, who has now retired – pushed hard for an innovative solution. Rather than opting for gas, which would save money in the short run, but at the cost of CO2 emissions, the decision was made to build an integrated system that combined multiple renewable energy sources.

The new pumping station draws water deeper from the lake at a constant temperature of 7°C. It is connected to next-generation heat pumps that raise the water temperature to 67°C thanks to a thermodynamic process that involves compression, condensation, expansion and evaporation, thus delivering significantly better energy performance.

The other major advance is that the plant makes use of thermal waste generated by a data center built on top of it, with server racks whose doors are designed to accommodate filtered industrial water cooled by lake water. This solution is energy-efficient but technically quite bold – normally, water and electronics are best kept far apart.

Cooling the servers to heat the rest of EPFL generates considerable electricity savings, particularly in comparison with the conventional approach of cooling the servers with refrigeration units. In a standard system, 3.3 units of electricity are needed to deliver one unit of electricity to the servers. Here, after factoring in savings in heating, this figure is 1.3 units, a 60% reduction.

What about plant waste?

The innovation doesn’t stop there. With solar panels covering the sides and roof of the building and a large space for pilot tests in the works, the plant could one day make use of a nearby composting facility, where plant waste from the neighboring campus’s parks and gardens is deposited. A digester for food waste from campus cafeterias could be another step towards small-scale local biogas production.

Nevertheless, the very small quantities of biogas produced would be insufficient to supply all of EPFL’s needs, according to David Gremaud, Energy Project Manager at the VP.

Energy savings

Switching from the oil-fired turbines to heat pumps will cut EPFL’s CO2 emissions by 1,800 metric tons a year. The energy savings from the solar panels will only be marginal, however, since they will generate a total of just 160 kW, whereas a single heat pump requires 2,000 kW. But according to Gianluca Paglia, a project manager for energy systems and construction methods at EPFL’s Sustainability Unit, having the solar panels installed directly on the building that houses a heating plant is a rare and instructive example of building-integrated photovoltaics – one of the topics addressed at CISBAT.

The construction work itself was delayed several times due to COVID – but also due to an infiltration of quagga mussels. These creatures, which live in the deep waters of Lake Geneva, colonized the heating system’s piping and other equipment. Engineers had to clean out the equipment thoroughly and install a new, removable strainer that allows for easier surface cleaning. They also introduced new filters.

Another issue that had to be dealt with was the discharge of wastewater from the cooling system into the local stream. The engineers designed a mechanism whereby the discharge valves could be regulated so as to preserve the local biotope, paving the way for the canton to approve the project’s environmental impact statement.

New data center will soon be up and running

The delays in the new heating plant also affected EPFL’s new data center, which is still under construction. The project managers are now waiting for the server racks to be delivered. “We’re operating on a tight schedule,” says Aristide Boisseau, the head of data center operations at EPFL. The new heating plant will be linked to a 1,000 m² data center that will eventually house 12 rows of servers, including one for the University of Lausanne. The server racks used at the data center will be slightly higher than conventional models and have water-cooled doors. It’s a design that’s already used in other buildings, but until now only for cooling purposes. The plan is to have the heat generated by the servers recycled into the heating plant, which should start this winter. That will increase the campus’ data storage and processing capacity, initially to half capacity at 2 MW, and then to 4 MW.

Space for running pilot tests

The last major advantage – and not the least – of the new heating plant is that it will include a large, raised area for running pilot tests. This space will be the size of six badminton courts and span an entire side of the plant’s building. Here, engineers will be able to run all kinds of experiments and demonstrations. “Before Philippe left, we made a shortlist of possible projects in the areas of both teaching and research,” says François Maréchal, a chemical engineer and professor of mechanical engineering at EPFL.

Indeed, the area lends itself to teaching purposes in a variety of ways, such as to explain system design and comparison, track operations data, reconcile measurements, improve process control and generate forecasts. It also opens the door to an array of synergies between EPFL labs, especially within the School of Engineering. For instance, Maréchal’s colleague Jan van Herle, a senior scientist at EPFL’s Group of Energy Materials (GEM) in Sion, is working on a fuel cell that can be installed at the heating plant to convert the biogas produced from organic waste into heat and electricity. Jürg Schiffmann, an associate professor at EPFL’s Laboratory for Applied Mechanical Design, has developed a new kind of compressor for heat pumps, and Prof. Mario Paolone at EPFL’s Distributed Electrical Systems Laboratory has come up with a way of integrating the heating plant into the smart system used to manage the campus’ electricity use.

Heating-system design is a field with much promise for the future, and Maréchal is encouraged by how EPFL’s own heating plant has evolved over the years.

Another promising development is the growing number of students who sign up for Maréchal’s class on energy system optimization. In this class, whose size has risen from 15 to 60 students in just a few years, Maréchal uses EPFL’s new heating plant as a case study. “Every engineer who is involved in energy systems must have one eye on the energy transition. It’s a crucial issue, and a highly motivating one for engineering students. While it requires a lot of work, it also shows students how important it is to analyze systemic ways of incorporating renewable energy in their designs. In the end, they’re quite proud of what they achieve.”

See the full article here .


Please help promote STEM in your local schools.

Stem Education Coalition

EPFL bloc

EPFL campus

The Swiss Federal Institute of Technology in Lausanne [EPFL-École polytechnique fédérale de Lausanne] (CH) is a research institute and university in Lausanne, Switzerland, that specializes in natural sciences and engineering. It is one of the two Swiss Federal Institutes of Technology, and it has three main missions: education, research and technology transfer.

The QS World University Rankings ranks EPFL(CH) 14th in the world across all fields in their 2020/2021 ranking, whereas Times Higher Education World University Rankings ranks EPFL(CH) as the world’s 19th best school for Engineering and Technology in 2020.

EPFL(CH) is located in the French-speaking part of Switzerland; the sister institution in the German-speaking part of Switzerland is the Swiss Federal Institute of Technology ETH Zürich [Eidgenössische Technische Hochschule Zürich)](CH) . Associated with several specialized research institutes, the two universities form the Domain of the Swiss Federal Institutes of Technology (ETH Domain) [ETH-Bereich; Domaine des Écoles polytechniques fédérales] (CH) which is directly dependent on the Federal Department of Economic Affairs, Education and Research. In connection with research and teaching activities, EPFL(CH) operates a nuclear reactor CROCUS; a Tokamak Fusion reactor; a Blue Gene/Q Supercomputer; and P3 bio-hazard facilities.

ETH Zürich, EPFL (Swiss Federal Institute of Technology in Lausanne) [École polytechnique fédérale de Lausanne](CH), and four associated research institutes form the Domain of the Swiss Federal Institutes of Technology (ETH Domain) [ETH-Bereich; Domaine des Écoles polytechniques fédérales] (CH) with the aim of collaborating on scientific projects.

The roots of modern-day EPFL(CH) can be traced back to the foundation of a private school under the name École spéciale de Lausanne in 1853 at the initiative of Lois Rivier, a graduate of the École Centrale Paris (FR) and John Gay the then professor and rector of the Académie de Lausanne. At its inception it had only 11 students and the offices was located at Rue du Valentin in Lausanne. In 1869, it became the technical department of the public Académie de Lausanne. When the Académie was reorganised and acquired the status of a university in 1890, the technical faculty changed its name to École d’ingénieurs de l’Université de Lausanne. In 1946, it was renamed the École polytechnique de l’Université de Lausanne (EPUL). In 1969, the EPUL was separated from the rest of the University of Lausanne and became a federal institute under its current name. EPFL(CH), like ETH Zürich(CH), is thus directly controlled by the Swiss federal government. In contrast, all other universities in Switzerland are controlled by their respective cantonal governments. Following the nomination of Patrick Aebischer as president in 2000, EPFL(CH) has started to develop into the field of life sciences. It absorbed the Swiss Institute for Experimental Cancer Research (ISREC) in 2008.

In 1946, there were 360 students. In 1969, EPFL(CH) had 1,400 students and 55 professors. In the past two decades the university has grown rapidly and as of 2012 roughly 14,000 people study or work on campus, about 9,300 of these being Bachelor, Master or PhD students. The environment at modern day EPFL(CH) is highly international with the school attracting students and researchers from all over the world. More than 125 countries are represented on the campus and the university has two official languages, French and English.


EPFL is organised into eight schools, themselves formed of institutes that group research units (laboratories or chairs) around common themes:

School of Basic Sciences (SB, Jan S. Hesthaven)

Institute of Mathematics (MATH, Victor Panaretos)
Institute of Chemical Sciences and Engineering (ISIC, Emsley Lyndon)
Institute of Physics (IPHYS, Harald Brune)
European Centre of Atomic and Molecular Computations (CECAM, Ignacio Pagonabarraga Mora)
Bernoulli Center (CIB, Nicolas Monod)
Biomedical Imaging Research Center (CIBM, Rolf Gruetter)
Interdisciplinary Center for Electron Microscopy (CIME, Cécile Hébert)
Max Planck-EPFL Centre for Molecular Nanosciences and Technology (CMNT, Thomas Rizzo)
Swiss Plasma Center (SPC, Ambrogio Fasoli)
Laboratory of Astrophysics (LASTRO, Jean-Paul Kneib)

School of Engineering (STI, Ali Sayed)

Institute of Electrical Engineering (IEL, Giovanni De Micheli)
Institute of Mechanical Engineering (IGM, Thomas Gmür)
Institute of Materials (IMX, Michaud Véronique)
Institute of Microengineering (IMT, Olivier Martin)
Institute of Bioengineering (IBI, Matthias Lütolf)

School of Architecture, Civil and Environmental Engineering (ENAC, Claudia R. Binder)

Institute of Architecture (IA, Luca Ortelli)
Civil Engineering Institute (IIC, Eugen Brühwiler)
Institute of Urban and Regional Sciences (INTER, Philippe Thalmann)
Environmental Engineering Institute (IIE, David Andrew Barry)

School of Computer and Communication Sciences (IC, James Larus)

Algorithms & Theoretical Computer Science
Artificial Intelligence & Machine Learning
Computational Biology
Computer Architecture & Integrated Systems
Data Management & Information Retrieval
Graphics & Vision
Human-Computer Interaction
Information & Communication Theory
Programming Languages & Formal Methods
Security & Cryptography
Signal & Image Processing

School of Life Sciences (SV, Gisou van der Goot)

Bachelor-Master Teaching Section in Life Sciences and Technologies (SSV)
Brain Mind Institute (BMI, Carmen Sandi)
Institute of Bioengineering (IBI, Melody Swartz)
Swiss Institute for Experimental Cancer Research (ISREC, Douglas Hanahan)
Global Health Institute (GHI, Bruno Lemaitre)
Ten Technology Platforms & Core Facilities (PTECH)
Center for Phenogenomics (CPG)
NCCR Synaptic Bases of Mental Diseases (NCCR-SYNAPSY)

College of Management of Technology (CDM)

Swiss Finance Institute at EPFL (CDM-SFI, Damir Filipovic)
Section of Management of Technology and Entrepreneurship (CDM-PMTE, Daniel Kuhn)
Institute of Technology and Public Policy (CDM-ITPP, Matthias Finger)
Institute of Management of Technology and Entrepreneurship (CDM-MTEI, Ralf Seifert)
Section of Financial Engineering (CDM-IF, Julien Hugonnier)

College of Humanities (CDH, Thomas David)

Human and social sciences teaching program (CDH-SHS, Thomas David)

EPFL Middle East (EME, Dr. Franco Vigliotti)[62]

Section of Energy Management and Sustainability (MES, Prof. Maher Kayal)

In addition to the eight schools there are seven closely related institutions

Swiss Cancer Centre
Center for Biomedical Imaging (CIBM)
Centre for Advanced Modelling Science (CADMOS)
École cantonale d’art de Lausanne (ECAL)
Campus Biotech
Wyss Center for Bio- and Neuro-engineering
Swiss National Supercomputing Centre