About the project:

The project will analyse potentials and feasibility of prospective expanders for organic Rankine cycles (ORC) based on impulse turbomachines and rotary vane expanders in power range of 1-50 kW. Based on three case studies (micro-cogeneration, waste heat recovery and low-temperature geothermal) three expanders will be designed (and optimised), built and tested: one rotary vane and two impulse turbines, including one highly innovative concept, for two different working fluids. Geometries and experimental data including many off-design operation states will be summarised and published to boost industrial development as well as research on expanders in this field. Feasibility mapping will be performed and published over the range of power and applications for the considered expander types.


Project DExpand aims at decentralized power production systems using a principle of organic Rankine cycle (ORC), converting heat to power. Applications are in decentralized and renewable sources such as biomass combustion, waste heat recovery, geothermal or solar thermal applications, eventually in novel storage systems as so called Carnot batteries. Case studies for selected applications were the first perfomed activity, providing a framework for the core focus of the project – expanders (turbines) – heart of these systems converting pressure potential to useful works and electricity. Then the design modelling and optimization of these expanders was initiated from fluid dynamics as well as mechanical design or manufacturing point of view.


Fluid dynamics design of the turboexpanders were optimized and mechanical design finished, most of the components were manufactured and are being assembled. Works continue on development of an off-design process model. The experimental track for MM was gradually improved, for isobutane, the compressor failed during start-up and is now being repaired.


The year 2023 was filled with mainly by experimental activities, including assembly, commissioning and experimental campaigns. Several set-backs, mechanical issues and redesign requests were encountered, yet experimental data were obtained for all four functional samples explored, three developed turbines and one volumetric expander. Additonal experiments are planned for year 2024.

Beneficiary and project partners:

České vysoké učení technické v Praze
GT-Progres, s.r.o.
Norwegian University of Science and Technology

The DEXPAND project benefits from a € 1.5 mil. grant from Iceland, Liechtenstein and Norway through the EEA Grants and the Technology Agency of the Czech Republic.
The project is carried out under the KAPPA funding programme for applied research, experimental development and innovation, managed by the Technology Agency of the Czech Republic.