Wood Chip Boiler

Baseground District- or Process Heating urgent required for the Cash Back of Biomass Power Engine



The Stirling based CHP system adds high value electricity production to an existing demand for heat

Plant description

The wood chips boiler solution is based on conventional biomass boilers for heating purposes.
A standard design from one of the leading European boiler manufacturers is modified to allow the hot flue gases to pass through the heater section of the Stirling engine to produce electricity.
Wood chips are fed through the stoker on to a grate in the combustion chamber of the boiler.
Primary air is added underneath the grate.
The biomass burns on the grate and the ashes eventually end up in the ash conveyor.

Part of the combustion chamber is fitted with a custom sleeve for the Stirling engine application.
This brick lined sleeve ensures higher temperatures with minimal heat transfer to the water cooled boiler surfaces.

Secondary air is added at the forefront of the sleeve.

The preheated secondary air and the insulating sleeve ensures a flue gas temperature of approx.
1250°C as the gases pass the heater of the Stirling engine, where a portion of the thermal energy is converted into electricity.



The flue gases leaving the Stirling engine heater panels are used for preheating the secondary air and are in turn forced through the two boiler tube

passes for heating of the circulating water. Water is also heated internally in the Stirling engine.
The only effluents of the system are the cooled flue gases and the ashes leaving the bottom of the boiler.


The system is ideal for small scale power production.

• Economical small-scale CHP-solution
• Small footprint
• Standard boiler with few modifications for Stirling operation
• Possible to remove Stirling engine for heat production only
• Fully automatic operation
• Automatic cleaning of heater panel
• Few components
• Proven boiler technology and proven engine reliability




The engine is designed for low maintenance and long life time.
The engine is hermetically sealed and is designed for service intervals up to 8000 hrs.
The heater panel is designed for biomass combustion and for easy cleaning.

Maintenance and operating costs of the boiler are comparable to a conventional biomass boiler of same size.




The Stirling based CHP system adds high value electricity production to an existing demand for heat.
The system can substitute existing fossil fuel based systems or can integrate with existing biomass boiler systems.
The produced electricity substitutes electricity bought from the grid, and excess electricity is sold to the grid.
To obtain a favourable return on investment the Stirling system must run as base load supported by other heating sources for peak load.

The system is suitable for local combined heat and power production in district heating systems, industry,housing communities, schools, public pools etc.
The system produces CO2-neutral heat and electricity and substitutes electricity from fossil fuels.

In many regions a favourable feed-in tariff exists for electricity produced from biomass, which adds to the feasibility of the system.
Please contact us for further information on feed-in tariffs, CO2- credits or installation grants in your region.

The small-scale biomass based CHP system gives a unique possibility to utilize local resources for a sustainable production of local heat and electricity.




Engine type NRGSD3

Fuel Wood chips
(or other solid biomass)
Moisture contents up to 50%
Electrical power, net 36 kW
Own consumption 3 kW
Heat production 215 kW
Water flow @ 45°C/80°C 5,3 m3/hr
Fuel consumption 290 kW
@ 40% moist 100 kg/hr
Electrical efficiency, net 12%
Plant efficiency 86%
Service intervals, engine 8000 hrs




1st step: Request Our Basic Engineering

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