Abstract <p>The article presents a review of the embodiments, in terms of construction material used (or shortly material embodiments), of the main heat transfer devices, namely, a vapor generator, condenser, and regenerative heat exchanger in the case of their optimal—in the authors’ opinion—use in the design of a thermal oil ORC unit. A shell-and-tube type device was considered for implementing both the thermal oil heated vapor generator and the water cooled condenser. A semi-welded plate device was also considered as an alternative to the latter. For an air cooled condenser, the material embodiment versions of devices with finned tube and microchannel heat transfer surface, and for the regenerative heat exchanger, versions with a plate-and-finned surface were studied. The choice of the most rational heat transfer, thermal insulation, and structural materials is substantiated with due regard to the specific features of the working media used. The currently-in-force regulatory documents stipulating the material embodiment of heat exchangers with suitable process operating conditions are analyzed, and an attempt is made to put the information in a systematic order using the experience of manufacturers as a basis. It has been found that the published catalogs of industrial equipment do not contain sufficient data on the materials used, technologies for connecting heat transfer elements (tubes with the tube sheet, plates, and heat exchanger components), and working media. As regards the proposals on the choice of material embodiment, they are limited to just one or two solutions. On the contrary, the regulatory documents present more various versions of materials. In the scientific-technical literature, materials that have not been yet put in operation and have not been included in standards are considered; however, they form promising ways for the development of this area. The performed analysis of all of the above-mentioned information sources enabled us to draw up recommendations on the optimal material embodiments for each of the devices considered, which ensure compliance with the unit’s operating conditions, including the temperature ones.</p>