Advance GAs Turbine for COgeneration – AGATCO

The main advantage of the AGATCO microturbine lies in superior performances for low power, its compact size, low weight, and high efficiency (~ 30%).
The system developed in this project is based on an entirely new concept and a manufacturing process allowing optimized aerodynamic tapered shafts (tunnels-type or helical channels) for the air and gas flow instead of blades. This gets possible by mastering the laser sintering of ceramic powders which is a novel concept itself.
Six major technological innovations are targeted:
- Use of an innovative ceramic powder developed especially for this project;
- Implementation of the laser sintering of ceramic powder which is a world-first experience which opens new opportunities for previously impossible viable solutions;
- Optimized aerodynamic pipes for air and gas flow instead of blades that allows to achieve efficiency of the compressor and the turbine higher than 74%, which is unparalleled in the today small-dimension energy devices;
- Temperature above 1100°C at the turbine inlet and introduction of a heat exchanger placed in a countercurrent manner between the compressor and the turbine makes it possible to consider an electric efficiency of about 30% that has been never reached;
- Development and control of the wood high-temperature combustion in a low-power burner to meet the requirements of the SEED call;
- Outsourcing of combustion and managing the interactions between combustion gases and the heat exchanger (fouling, corrosion).
A biomass boiler with low particles emission will be developed especially in the framework of this project.

The development and production of a ceramic powder resistant to high temperature, possessing low density, undergoing no shrinkage allows the use of the laser sintering for manufacturing innovative complex shapes that until now would have been impossible. The concept of tunnel-type micro-turbine achievable only by laser sintering and for low power can provide high yield that makes viable the use of the microturbine.
The development of the laser sintering of metal and ceramic powders has been undertaken in order to obtain good quality 3D parts: homogeneous, without pores or cracks, with a surface of a controlled roughness.
The development of a high-temperature wood boiler comprising a particulate filter reduces the amount of gas pollution emitted from the boiler, and also prevents the heat exchanger used in our project against fouling. The rotors of the compressor and of the turbine made in ceramic material by laser have been mounted on the rotor of the electric generator also made within this project. The overall construction has been balanced on a test bench purposely designed for our project. The links and connections of the micro-turbine-boiler and the heat exchanger have been defined and are being implemented with the associated measures. The design of the particulate filter has been studied, its positioning in the boiler is being defined, and manufacturing process is completed.

Our project should enable distributed power generation at the individual habitation scale in the form of micro-cogeneration (local electricity and heat autonomous production). It offers an alternative to conventional boilers by developing domestic CHP appliances. They meet two social issues: first, the reduction of energy consumption and, second, the control of the electrical networks to be contributors of an increasing share of renewable energy.
The developed concept of cogeneration allows the system to be self-sufficient in electricity and also to extend electricity supply to some isolated areas through an independent network.

Study of the laser sintering of innovative powders - superalloys and cermets - performed at ENISE led to the defense of two M.Sc. theses (PhD School SIS 488 ENISE - Ecole Nationale Superieure des Mines de Saint-Etienne - Jean Monet University) in 2014.
Developments in selective laser sintering were presented at sessions of the French Association of Rapid Prototyping (AFPR).
A patent has been filed on the ceramic material and the process for obtaining the ceramic powder, the license could subsequently sold to a company specializing in this type of product for its industrial production for various applications.

Cogeneration - Combined Heat and Power generation by gas micro-turbine (micro-CHP) - is a very progressive industrial and ecological concept, since it can reach a very high efficiency up to 90%, and greatly minimize CO2 and NOX emission.
Metals are currently used in gas micro-turbine applications, as their thermal, mechanical and dymanic characteristics are well known. However, metals are approaching their limit with respect to maximum operating temperature, and alternatives are being sought. To fully reveal its potentials, CHP turbine shall operate at very high temperature, about 1350°. The use of metallic materials is therefore no more possible and ceramic material must be considered.
Ceramics present a promising alternative as they are generally lighter and having considerably higher strength at high temperatures, better refractory and corrosion-resistance than metals.
Ceramic gas turbine can run at temperatures up to 1370°C compared to about 700°C of all-metal turbines. That is why ceramic turbines can achieve 30-40% greater efficiency than all-metal turbines. If high-temperature ceramics were incorporated through-out gas turbines in the electricity generation sector, 1.4 quads of energy could be saved annually (Data of U.S. Department of Energy, 2010).

This Project aims to develop an innovative apparatus for low-power cogeneration of heat and electrical energy (2.0 kW power) operating with gaseous fuels such as natural gas or propane and adaptable to other fuels in the future. Within this system, the electricity will be produced by a micro-ceramic turbine driving an electric generator integrated into a rotating assembly mounted on gas bearings. Targeted outcomes are an electrical efficiency of about 28% to 30%. Miniaturised electric generator of original design will meet these technical specifications as well as safety requirements for electric devices. A total return (electricity + heat) is targeted close to 90% due to ceramic heat ecxhanger. Along with this, micro-CHP apparatus will feature extremely low pollution levels thanks to ceramic combustion chamber of a specific design.

The Project propose radically innovative “integrated design- and manufacturing” approach to manufacture micro-CHP apparatus, since the straight-forward attempts for miniarturisation / ceramisation of metallic turbines have clearly shown their uselessness.
To make a real step-forward in micro-CHP, the Project aims is to combine (i) innovative ceramic engineering powders specially tailored for high-temperature mecanical applications; (ii) a newly developed design of micro-turbines: helical internal channels that will replace classical miniaturized blades in the turbines; (iii) Selective Laser Sintering as manufacturing technolology as it is the unique currently existing production process allowing complex customised ceramic parts with controlled external and internal geometry.

Two prototypes of cogeneration apparatus will be delivered and comprehensivelly characterised for their performance. An engineering study of micro-CHP implementation itno domestic heater will be also accomplished taking into account the existing relevant technical / explitation / safety reglamentations. A functional prototype of domestic cogenerator will be realised and tested in the industrial test-bench by project partner SILENE.