The valorization of low-temperature waste heat within industrial processes undoubtedly plays a crucial role in
improving overall energy efficiency of industrial processes. The European Union launched several projects that aim
at the development of innovative technologies to generate electricity by recovering low-temperature waste heat (<
120°C) using ORC. One of the basic concepts that will be investigated for heat extraction from gases is a direct heat
exchanger, which is a finned-tube evaporator featuring a direct exchange between flue gases and the working fluid.
For wet gas heat sources (T dp > 50°C), the temperatures of tube and fin surfaces are generally below the water dew
point temperature, leading to simultaneous heat and mass transfer tube and fin surfaces, then part of the finned-tube
evaporator will operate in dehumidifying conditions.