Mauro Scattolini

Vapor+Liquid Equilibrium Measurements and Correlation of the Binary Refrigerant Mixtures Difluoromethane (HFC-32)+1,1,1,2,3,3-Hexafluoropropane (HFC-236ea) and Pentafluoroethane (HFC-125)+1,1,1,2,3,3-Hexafluoropropane (HFC-236ea) at 288.6, 303.2, and 318.2 K

Isothermal vapor–liquid equilibria (VLE) for the binary systems of difluoromethane (HFC-32)+1,1,1,2,3,3-hexafluoropropane (HFC-236ea) and pentafluoroethane (HFC-125)+1,1,1,2,3,3-hexafluoropropane (HFC-236ea) were measured at 288.6, 303.2, and 318.2 K using an apparatus in which the vapor phase was recirculated through the liquid. The phase composition at equilibrium was measured by gas chromatography, based on calibration using gravimetrically prepared mixtures. Both systems show a slight deviation from Raoults law. The uncertainties in pressure, temperature, and vapor- and liquid-phase composition measurements were estimated to be no more than ±1 kPa, ±0.02 K, and ±0.002 mol fraction, respectively. The data were analyzed using the Carnahan–Starling–DeSantis equation of state.

Nanofluids characterization and application as nanolubricants in heat pump systems

In the last years, various applications have been proposed for nanofluids in the HVAC&R field; their use as primary and secondary fluids, also as lubricants, has been kept into account to improve systems performance. The present work was developed to test the applicability of nanofluids as lubricants in the compressors of heat pump systems, with the purpose to experimentally detect the possible positive effects of nanolubricants. Several nanolubricants, formed by polyolester or mineral oil as a base fluid, and titanium oxide (TiO2) or single-wall carbon nano-horns as nanoparticles, were studied in a dedicated test rig. In contrast with some published data, no improvement was detected with 0.05 to 0.5 wt% of TiO2 or 0.1 wt% of single-wall carbon nano-horns in tested commercial oils. All results will be discussed in depth in the article.