The behavior of a counter-current tube-in-tube heat exchanger for fluid foods, was simulated under different operating conditions with a Computational Fluid Dynamics (CFD) parametric study. Three input parameters (product velocity vp,in, inlet product temperature Tp,in and inlet water temperature Tw,in) and two output parameters (outlet product temperature Tp,out and pressure drop across the heat exchanger Δp) were chosen. The results highlighted that the relative impact of vp,in on Δp was positive (93%), while higher Tp,in and Tw,in yielded lower pressure drop values (−3% and −4%, respectively). Tp,out was influenced positively by inlet product (62%) and water (22%) temperatures, and negatively by vp,in (−16%).A Response Surface (RS) was then generated and validated with a suitable experimental campaign. A good agreement was found between the simulated and the experimental results: Tp,out and Δp have been calculated with mean errors of 0.85 K and 628 Pa, respectively, thereby confirming the potential value of the RS as a Reduced Order Model, which could be used to develop a Digital Twin of the device. This modelling approach leads to a significant state-of-the-art improvement, allowing m the results of the CFD simulations to be ready-to-use, and granting deeper knowledge and finer control of the system.