1 Marius Wöhler Prof. Dr. Stefan K. Pelz University of Applied Forest Sciences Schadenweilerhof Rottenburg am Neckar Advanced Testing Methods for Better Real Life Performance of Biomass Heating Appliances

2 Introduction Background Method Results Conclusion Outline

 Located in Rottenburg (50 km south of Stuttgart)  1300 students  2500 ha research forest 3 HFR – University of Applied Forest Sciences Bachelor courses Master courses  Forest Sciences  Renewable Energy  Forest Products  Water Resource Management  Sustainable Regional Management & Tourism  Sustainable Energy Competence (SENCE)  Resource-efficient Construction  Tropical Forestry

 Research from solid biomass feedstock to emissions and efficiency of small scale combustion appliances (up to 200 kW)  National and international research projects  Chemical laboratories to analyze all relevant parameters of feedstock, fuels and combustion-behavior and -residues  Two combustion laboratories to analyze emissions of combustion appliances  PM: gravimetric and optical measurement  Gaseous emissions: FTIR, NDIR, FID and various handhelds Feedstock Logistics Pretreatment Storage Combustion Emissions Residues

5 Type testing - Notified body - Defined test method (e.g. EN 13240) Sale of stove (identically constructed Comply with thresholds (different in Europe) Type testing ≠ Real life operation New stoves ≠ low emissions in real life Background No inspection at operation place

Objective: Development of advanced testing methods for room biomass heating appliances to better reflect real life operation Knowledge about how stoves are used in real life operation is crucial Online Survey in Europe  28 questions about heating appliance, installation conditions, user behavior and fuel  available in seven languages  online for 14 consecutive weeks  Field monitoring  9 pellet stoves were monitored for 100 days in field operation  Temperature and draught measurement Method

 2205 completed questionnaires  Good regional distribution along different climate zones in Europe  Data evaluation separately for different types of heaters Firewood stoveTiled stoveCookers Pellet stoves Wöhler M. et al. (2016): Investigation of real life operation of biomass room heating appliances – Results of a European survey. Applied Energy;169:240–9. n= 1980 n= 174 Results

 Average age of pellet stoves: 3 years  Average heat output: 11 kW  5 – 10 m chimney height was most common  62 % of stoves were without water jacket Installation placePellet stoveFirewood appliances House 79 %87 % Apartment 17 %9 % Other kind of building 2 %3 % Non-residential building2 %1 % Pellet stoveFirewood stove Yes, but stove is primary heating system 59 %31 % Yes, stove is secondary heating system 14 %55 % No28 %14 % Is the installation room additionally heated by another heating system? Installation place of the stove? Selected questions

How is the heat output of your stove controlled ? Adjustment of the heat output directly on the stove control panel 35 % The stove is controlled by a room thermostat 36 % The stove is controlled by a clock timer 25 % Control of the stove by using a web based system 0 % None of the described 4 % 71 % of the users stated that they adjust the heat output of the stove at the control panel even if a automatic control system is available. Results

Is the heat exchanger of your stove cleaned regularly? Yes, done by the user 61% Yes, done by a service technician 22% No, it has not been done yet 5% The stove provides an automatic cleaning system 6% I do not know 7% Is your pellet stove serviced by the manufacturer, the installation company or other technician? Good level of knowledge about the maintenance of pellet stoves Strong customer – industry relationship Results

Where do you buy your wood pellets? Buying from specialized fuel dealer 61% Buying from do-it-yourself store or normal retailer 37% Buying from Internet shop 2% Other supply option 15% Results Are the wood pellets which are you using tagged as "ENplus“?

Conclusion Conclusion based on the online survey and the field monitoring  Start-stop-operation is common for pellet stoves in Europe  The initial combustion phase is a significant part of the total heating operation (share of 39% of the operation time)  Manual setting of the heat output by the user is common  The operation in full load is unusual and was monitored at only 10% of the stove operation time  It seems that pellet stoves in Europe are well serviced and operated mainly with certified pellets Type testing which reflects the real life operation should definitely included all steady and transient combustion phases in a realistic proportion.

13 Project is still ongoing Updated information available at: The research leading to these results has received funding from the European Union Seventh Framework Program (FP7-SME-2013) under Grant Agreement n

14 Marius Wöhler Prof. Dr. Stefan K. Pelz University of Applied Forest Sciences Schadenweilerhof Rottenburg am Neckar Advanced Testing Methods for Better Real Life Performance of Biomass Heating Appliances