Nanofluids Characterization and Application as Nanolubricants in Heat Pumps Systems

In the last years, various applications have been proposed for nanofluids in the Heating, Ventilation, Air Conditioning and Refrigeration (HVACR) 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 (POE) or mineral oil, as base fluid, and titanium oxide (TiO2) or single wall carbon nano-horns (SWCNH), 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 SWCNH in tested commercial oils. All results will be deeply discussed in the paper.