Abstract:
Experimental runs were performed to investigate the variation of the 'evaporator Nusselt number with the Reynolds number, the heat flux and the nano-Particles concentration in a refrigeration system. The used refrigerant is TiO2/R134a nano-fluid at different values of nano-particle concentration. Next, the refrigeration system was modified with an auxiliary evaporator and a control unit which will store the experimental results. These results will be used as a guide to distribute the mass and heat fluxes between the two evaporators. So, it is possible to control the Nusselt number and accordingly, to achieve a predetermined variation of the cooling behavior in more than one evaporator. The experimental results showed that, for all studied cases, the Nusselt number increased with the Reynolds number and the heat flux. The Nusselt number also increased with the Nano-Particle concentration up to the value of 0.5, and beyond this value, its enhancement started to deteriorate. When increasing the Reynolds Number by about 98 % the Nusselt number could be enhanced by about 67 %. Two correlations were suggested to fit the data of the Nusselt number, the heat flux, and the nanoparticles concentration. This research work is a step towards the control of many cooling loads using one compressor.
