The conventional mixture of base fluid (mixture glycerol - water and water) are dispersed nanoparticles of aluminum (III) oxide, in different concentrations, in order to improve thermal conductivity of nanofluida. The dispersion of nanoparticles in suspension is achieved by the action of ultrasonic waves in the liquid, and the stability is improved by the addition of polyvinyl alcohol. The coefficient of thermal conductivity, density, viscosity and specific heat capacity have been measured for prepared suspensions. The measured thermo - physical properties were compared with the data calculated from different theoretical models. The volume of thermo – physical properties has been compared with and without additives (PVA). Addition of PVA reduces the thermal conductivity and significantly increases the viscosity of nanofluida. Prepared nanofluids were used while heating water in the plate heat exchanger and the heat transfer coefficient is determined based on the nanofluid. Increasing of the flow increases the coefficient of heat transfer due to reduced layer of the hydrodynamic and thermal boundary. By increasing the concentration of nanoparticles the heat transfer improves regardless of the value of thermal conductivity. It can be concluded that the presence of nanoparticles in the fluid influences the structure of the boundary layer, and the Brownian movement which is present in nanofluids causes convection which results in an additional improvement of heat transfer in nanofluids.