Within the project “Test stand method for the determination of system efficiency and emission factors of small-scale biomass combustion systems “ a test stand measurement method for the determination of annual system efficiency and emission factors of small-scale biomass combustion systems has been developed. The method should allow deriving realistic annual system efficiencies and emission factors under unsteady conditions.

Measurement setup, techniques and position of sensors should be according to the default boiler testing standard EN 303-5 to use the same infrastructure. For evaluation of measurement data an easy-to-use software was designed, which is capable of calculating the annual efficiency and the emission factors for a boiler heat storage combination too.

Figure: Development of the reference-cycle from daily load profiles

According to the developed measurement method 3 pellet boilers, 1 wood chip boiler and a log wood boiler were tested on 3 different test stands. The evaluation of the measurement data shows the suitability of the new method to quantify the stage of development of modern small-scale biomass boilers.

Values for annual standard system efficiencies measured on test stand are comparable to published results from field tests. The modulating operation of the biomass boilers results in lower annual efficiencies compared to operation with heat storage tanks. Efficiency is increased if the heat loss of the storage is considered too. The derived annual emission factors are comparable to values from field tests. Because of the small amount of tested boilers there is still a difference to published emission factors.

The results of our experiments show that the newly developed method is a good tool to evaluate small-scale biomass boilers. With this method we provide an easy and reliable tool to determine annual system efficiencies and emission factors for realistic boiler operation.

The project has been accomplished in cooperation of Bioenergy 2020+ GmbH, Federal FJ-BLT Research Institute for Agricultural, Agricultural Engineering and Food Technology, TFZ Technology and Support Centre Straubing and AEE Arbeitsgemeinschaft Erneuerbare Energie Kärnten. DIt has been performed and funded within the framework of the program „ENERGIE DER ZUKUNFT“. This program is handled by the Austrian Research Promotion Agency (FFG) by order of the Federal Ministry for Transport, Innovation and Technology (BMVIT) and the Federal Ministry of Economy, Family and Youth (BMWFJ).

Downloads
Final report, manual and software will be available for download after approbation by FFG in this place

Contacts at Bioenergy 2020+
Matthias Heckmann
Markus Schwarz

2010-10-11