The development and research regarding nanofluids has been more encouraged by the industry due to the significant improvement of the thermo physical properties of these fluids, such as thermal conductivity, thermal diffusivity, viscosity and heat transfer coefficient. The automotive industry has a big potential in using these nanofluids since there are several systems such as transmission, cooling, lubrication and other that can benefit from the high thermal conductivity offered by the accurate selection of the nanofluids. The aim of this paper is scaling a secondary loop air conditioning system to make feasible the use of the HFO-1234yf coolant as an alternative to the fluid R-134a that is currently used. This motivation occurred for the need of substituting the coolant made of HFC and HCFC, which are currently used, due to environmental issues. Besides using a new coolante, the project aims to propose a new and innovative alternative to the secondary fluid, the carbon nanotubes nanofluid. This air conditioning system project was developed to a specific vehicle, a van with a given thermal load according to the operating conditions considered.