Industrial processes lead to a dispersion in the environment of high amounts of thermal energy in the form of hot flows generally in the gaseous and liquid form. The possibility of exploit these energy forms represents a challenge for the research that could be overcome through the development of materials thermo and pyroelectric as bulk and thin films for the production of generators. In particular thermoelectric materials in bulk form are already used both in the aerospace field as radioisotope thermoelectric generators (REG) and in military applications and are on the market (TEG), as in Peltier cells. A large-scale application such as TEG requires the realization of components based on efficient materials with low cost production processes.

The activities foreseen in WP1 will be focused on the study bulk and thin film materials with good functional characteristics and low environmental impact through the development and implementation of conventional and unconventional fabrication techniques with features of low cost, environmental-energetic sustainability and strong industrial scalability. In WP2, exploratory thermoelectric and pyroelectric modules at the solid state will be designed, tested and validated on the laboratory scale. In the case of thermoelectric materials, interconnections between active materials will be studied and different circuit geometries and architectures for the realization of proof of concept devices will be tested.

In particular, it is planned to realize TEG with inorganic or hybrid thin film with low power (in the nW- µW range with temperature differences of a few degrees centigrade), adaptable to energy sources and with good stability in the temperature range below 200 ° C, and prototypes of pyroelectric generators with pyroceramic components. The main models, and some variants, of thermoelectric generators of the vertical type have been identified. A pair of materials suitable for experimentation was identified. The thermal networks and the related calculation routines were studied, preparatory to the design of the final system in terms of geometric layout for low temperature applications, and various printing techniques analyzed. The architecture and general specifications of the pyroelectric devices to be produced through printing processes were selected for the potential realization of low-cost microgenerators. A preliminary feasibility study was carried out on pyroelectric components of the demonstrators and pyroceramic components to be included in the demonstrators that will be developed.

WP3 and WP4 are focused on different aspects of Additive Manufacturing, mainly considering the possibility of integrating or substituting traditional manufacturing process, i.e. subtractive and foundry ones, for the realization of components for energy applications. The project is focused on advanced materials, being one of the main challenging aspects in these processes. Interesting technologies, as Atomic Diffusion Additive Manufacturing (ADAM) or Bound Metal Deposition (BMD), allow to realize metallic components starting from composite material, generally polymeric with metal. The process is completely different respect to metal 3D printing processes, as powder bed or direct metal deposition. In the project the development of metal composites for these additive manufacturing processes will be under study, considering both the two aspects related to binders and charges. Moreover a plasma atomization machine, designed in ENEA, will be used to realize powders, even with customized composition, for AM processes, as charges for composites and slurries and for powder bed or direct deposition. The project will consider also the realization of composites with functionalized nanoparticles, even in the form of core-shell particles, to be used for improving their properties. In solar cooling and heating systems based on ammonia-water cycles, severe environment conditions could be present which heavily stress the materials. Nickel and copper are highly affected by ammonia corrosion. For this reason a new ferrous ODS alloy, with suitable thermal properties, is under study to be used for the realization of heat exchangers by additive manufacturing processes. One of the aims of the project, starting from previous activities, is in fact the realization by 3D printing of an heat exchanger for its use in absorption machines. The  realization of heat exchangers in polymeric composite materials with micro and nano charges, will be considered also for less severe conditions and for the optimization of the heat exchanger design. Another activity in the project will be the optimization of 3D printable feedstocks for advanced ceramic components. Printable ceramic pastes, with optimized rheological properties, will be formulated for 3D printing based on material extrusion and in particular for Liquid Deposition Modeling (LDM) process. The printing strategy and thermal treatments will be optimized up to obtain sintered components, demonstrating the effectiveness of the 3D printing process. The advanced ceramic components will be properly designed as promising to improve the working temperature and the efficiency of energy production processes based on biomasses. Considering the impact of failures in energetic processes, as the case of turbines for energy production or lightweight components, the aspects related to quality, as presence of defects in as built 3D printed metallic components, will be studied with different approaches: microstructural analysis, non-destructive and mechanical tests, tribological and wear tests. Furthermore the optimization of laser-based 3D printing processes and the realization of improved heat pipes, for heat dissipation, and Pelton impellers, for mini and micro hydro, by additive manufacturing will be studied within the project.

The persons in charge for the activities of the 4 work packages are listed below:

WP1 - Dr.ssa Francesca Di Benedetto
WP2 - Dr.ssa Amelia Montone
WP3 - Ing. Daniele Mirabile Gattia
WP4 - Dr.ssa Federica Bezzi