Aluminium III oxide (Al2O3) nanoparticles have been dispersed into the mixture of a fluid (water and glycerol) in different concentrations with or without the stabilitator with the aim to improve thermal conductivity. Having achieved the stability of suspensions of different concentrations, the rheological behaviour of the prepared nanofluids has been determined, and coefficient of thermal conductivity also as the specific heat capacity have been measured. Different theoretical models have been compared with the experimentally obtained values of thermo-physical properties of nanofluids. By applying nanofluids in the plate heat exchanger the heat transfer coefficient and overall heat transfer coefficient have been calculated as well as the efficiency of the plate heat exchanger at different flows. Likewise, measurements have been carried out with the fluid which contains Tween 20 stabilitator. This stabilitator has been selected as prime among the tested samples (Arab rubber and Triton X100). Rheometrical measurement has affirmed that nanofluids indicate Newton's behaviour with slight increase in density and viscosity comparing to the base fluid. Improving of hydrodynamic conditions in the heat exchanger leads to heat transfer coefficient increasing. The achieved efficiency in the heat exchanger is high, being diminished at higher flows of hot fluid and with the increase of nanoparticles concentration. By comparison with the values obtained for water in laminar flow conditions, values of m exponents in the correlation equations obtained for nanofluids have been increased.