The MisceLab laboratory, a recently established facility at Politecnico di Milano, is partially funded by the NEST project and supported by the Next Generation EU programme. Its goal is to characterise innovative working fluids and mixtures for applications in direct (power generation) and inverse (heat pumps and refrigeration systems) thermodynamic cycles.

The laboratory is equipped with systems for measuring density, viscosity and calorimetric properties, and a dedicated apparatus for vapour-liquid equilibrium (VLE) measurements. Unique systems are used to create the charge and manage the fluid to be analysed, making it possible to create pressurised mixtures with multiple components, starting from pure fluids stored individually and separately.

Once the mixture has been created, with its composition carefully measured, it can be distributed to all the measuring instruments present. In particular, measurements are carried out at a constant temperature (by immersing the measuring equipment in thermostatic baths), manually or automatically controlling the pressure of the fluid to be analysed by means of variable volumes in line with the measuring instrument. Particular importance is given to the instrument for analysing the composition of the two phases of the mixture in liquid-vapour equilibrium conditions: the laboratory is equipped with advanced systems for sampling the fluid from both phases in equilibrium (ROLSI), evacuating it from the cell and transporting it to the gas chromatograph analyser.

The purpose of the measurements is to characterise the density, heat capacity and viscosity of fluids and their mixtures in single-phase conditions (liquid, gas or even supercritical), imposing composition, pressure and temperature for each measurement. The apparatus for liquid-vapor equilibrium (VLE) measurements is used to determine, in a temperature range from -20°C to 150°C, the pressures and compositions of the two phases in liquid-vapor equilibrium, which are considered crucial as thermodynamic points of closed thermodynamic cycles, both direct (power generation) and reverse (heat pumps and refrigeration systems). The measurements are therefore aimed at supporting the best definition/calibration of EoS (equations of state) of the thermodynamic properties of fluids, in order to improve the accuracy of the calculation codes for simulating the performance of thermodynamic cycles based on the applications of interest.