temperature – Progress in Research

Electricity: how to take advantage of the heat generated by industrial processes?

Posted on 16/01/202406/08/2024 by Erik Franco

The current need to reduce pollutant emissions and mitigate the effects of climate change calls for innovative avenues in the field of electricity production. Paradoxically, in industry, significant amounts of heat are lost to the environment by energy-intensive processes such as those in glass, cement, metals, paper and food. This neglected resource could instead represent a significant contribution to decarbonisation, with an estimated potential of 5% of the EU’s total electricity needs. This is equivalent to the electricity consumption of 20,000,000 households or the production of 19 large power plants.

Exploiting this possible energy source is the objective of the POWHER project, coordinated by Prof. Andrea Spinelli and Prof. Alessandro Romei of the Department of Energy at Politecnico di Milano and financed by the European Union (Next Generation Europe) within the framework of the Research Projects of Significant National Interest (PRIN – MUR).

Exploiting waste heat from industry is crucial for a sustainable energy future. POWHER aims to turn this potential into reality with innovative solutions.

The approach used by the POWHER project is based on Organic Rankine Cycles (ORCs), a technology similar to traditional steam cycles which uses the vaporisation of an organic fluid instead of water. This choice allows the construction of simpler and cheaper systems with good conversion efficiencies.

The focus of researchers at Politecnico di Milano and the University of Bologna is the implementation of Partial Evaporation Organic Rankine Cycles (PE-ORCs), an innovative version of ORCs. This solution could increaseefficiency by up to 30% through incomplete evaporation of the organic fluid. Both theoretical and experimental studies will focus on overcoming the challenges that have so far hindered the adoption of this technology: the development of efficient turbines for two-phase (liquid-vapour) fluids and the optimisation of plant control strategies.

The experimental activities will take place at the Test Rig for Organic VApors (TROVA) at Politecnico di Milano, one of the few experimental apparatuses in the world suitable for studying the motion of organic fluids at high speed and temperature.

The POWHER project thus promises to be an important step towards a sustainable energy future, making innovative use of an often neglected resource and paving the way for efficient power generation solutions.

Towards more sustainable superconductor applications

Posted on 11/12/202306/08/2024 by Erik Franco

A significant step forward in superconductivity research has recently been made. The discovery could pave the way for sustainable technologies and contribute to a more environmentally friendly future.

The study just published in Nature Communications by researchers from Politecnico di Milano, Chalmers University of Technology in Göteborg and Sapienza Università di Roma sheds light on one of the many mysteries of high-critical-temperature copper-based superconductors. Even at temperatures above the critical temperature, they are special, behaving like “strange” metals. This means that their electrical resistance changes with temperature differently than that of normal metals.

This is the result of more than five years of work. We used a technique, called RIXS, largely developed by us at the Politecnico di Milano. Thanks to numerous measurement campaigns and to new data analysis methods, we were able to prove the existence of the quantum critical point.
Giacomo Ghiringhelli, Professor at the Department of Physics and coordinator of the research

The research hints at the existence of a quantum critical point connected to the phase called “strange metal”. A quantum critical point identifies specific conditions where a material undergoes a sudden change in its properties due solely to quantum effects. Just like ice melts and becomes liquid at zero degrees Celsius due to microscopic temperature effects, cuprates turn into a ‘strange’ metal because of quantum charge fluctuations.

The research is based on X-ray scattering experiments conducted at the European Synchrotron ESRF and at the British synchrotron DLS. They reveal the existence of charge density fluctuations affecting the electrical resistance of cuprates in such a way as to make them “strange”. The systematic measurement of how the energy of these fluctuations varies allowed identifying the value of the charge carrier density at which this energy is minimum: the quantum critical point.

The discovery represents an important advancement in understanding not only the anomalous properties of the metallic state of cuprates, but also the still obscure mechanisms underlying high-temperature superconductivity.

A better understanding of cuprates will guide the design of even better materials, with higher critical temperatures, and therefore easier to exploit in tomorrow’s technologies.

Arpaia, R., Martinelli, L., Sala, M.M. et al.
Signature of quantum criticality in cuprates by charge density fluctuations.
Nat Commun 14, 7198 (2023)

Read the study online

Glide4Heat: promoting transformation of heat pump and refrigeration technologies

Posted on 29/11/202306/08/2024 by Erik Franco

The research project Glide4Heat, funded by the Ministry of University and Research (MUR) as part of the Projects of Relevant National Interest (PRIN), has officially kicked-off under the coordination of Professor Luca Molinaroli. Its aim is to revolutionize the use of eco-friendly technologies.

Researchers from the Politecnico di Milano – Department of Energy, the Università degli Studi di Udine and the Università degli Studi di Padova will study carbon dioxide and hydrocarbon mixtures with the aim of redefining the applications of high-temperature heat pumps and refrigerators in accordance with European environmental regulations.

The project involves theoretical and experimental activities. The experimental apparatus has been installed in the refrigerant fluids laboratory of our Department of Energy, where researchers will test different refrigerant mixtures and characterizing both the system and the compressor.