The article discusses various types of expanders used in the organic Rankine cycle systems to turn thermal energy into electrical energy. In addition to basic information on scroll, screw, vane, piston, and turbine expanders, the paper also describes the principles of their operation as well as major advantages and disadvantages. The following characteristics of expanders have been developed on the basis of the most recent scientific publications and own experimental research conducted at the IFFM PASci, in Gdansk. The analysis of various expansion devices available on the market, including those that are still in the development phase, revealed a wide variety of problems related to their operation. The design differences between them have a significant impact on their efficiency and reliability when operating with different working fluids. The article is an authoritative compendium of research-based information about designs and performance of various types of expansion devices. It may be useful for people who want to apply such devices in different types of cogeneration systems.

The paper discusses the research on foil bearings with antifriction coating manufactured from synthetic materials. The tests were carried out on a special test stand of our own construction, designed with the use of numerical analysis. In the course of the experimental studies, the test stand was set up in two configurations: with one or two foil bearings. The measurements were done, which focused on temperature distributions with the aid of thermocouples and thermovision camera. The measurements were being performed under varying conditions of bearing operation. The conducted experiments permitted to verify the durability, thermal characteristics, and dynamic performance of foil bearings in different configurations. An original method to measure temperature of a top foil has been worked out.