Development and validation of a physical based model of heat exchangers for an Organic Rankine Cycle power plant, with R245fa as operating fluid. The main goal was to recreate a virtual model of a specific brazed plate heat exchanger, modelling its geometry and the heat exchange between the hot side and the cold side, using the simulation software GT-Power. In order to effect this, it was necessary to study the heat flow of these types of exchangers, to learn the fundamental variables and how these influence the constitutive equations, with the aim of being able to correctly develop a model that would describe the reality of the exchange.