Application of nanofluids in industrial processes. The case of food processing

A crossflow heat exchanger for drying purposes integrated in a pasta manufacturing process is considered in the present work. Different nanofluids, i.e., Al2O3, TiO2, and CuO, are considered with particle dimensions ranging from 20 to 60 nm and volumetric concentration in the range of 0 %–5%. Base fluid is water. An analytical model of the heat exchanger is developed and the energy performance is evaluated from a Life Cycle Analysis perspective by considering the embodied energy of the different nanoparticles. The utilization of the nanofluids allows to reduce the dimensions of the device. In particular, a reduction in length of 26 %, 25 %, and 27 % is estimated for Al2O3, TiO2, and CuO respectively. Oppositely, there is not an enhancement of the energy performance. In particular, an increase of the operating energy is detected since the reduction of the dimension increases pressure losses and the saving in embodied energy due to the use of less material is not sufficient to offset the increase in embodied energy due to the utilization of the nanoparticles.