Residential Wood Combustion (RWC) -

Residential Wood Combustion (RWC) Investigation of user behavior and operating conditions regarding
stoves and their impact on emissions and efficiency
4th Central European Biomass Conference
Gabriel Reichert, Christoph Schmidl, Walter Haslinger, Wilhelm
Moser, Stefan Aigenbauer, Franz Figl, Marius Wöhler
Graz, 17.01.2014
Central European Biomass Conference 2014
Content
■ Background
■ Objectives
■ Materials & Methods
■ Survey
■ Field tests
■ Results
■ Survey
■ Field tests
■ Summary & Conclusions
Graz, 17.01.2014
Slide 2
Central European Biomass Conference 2014
Background
Current situation of RWC appliances in real life operation
Firewood roomheaters, cookers, insets and open fireplaces
Technical progress
according to EN 13240, 12815 & 13229
Emission
Graz, 17.01.2014
Slide 3
Standard type
test
! Discrepancy !
?
 Technology
 User behavior
 Operating conditions
?
apparent value
actual value
Real life
operation
Efficiency
Central European Biomass Conference 2014
Objectives
■ Investigation of user behavior of RWC appliances by a
survey
■ Assessment of operating conditions of RWC appliances
in real life operation
■ Investigation of impact of user behavior and operating
conditions on emissions and efficiency
Development of a new test method for RWC
appliances reflecting real life operation
Graz, 17.01.2014
Slide 4
Central European Biomass Conference 2014
Materials & Methods
Survey of RWC users
■ Based on a questionaire
■ Consisting of 15 closed questions
■ Personal interviews (114 respondents)
■ Performance at a tradeshow in Lower
Austria
■ Structure:
■
■
■
■
Generals (type of technology)
Kind and quality of used fuels
Operating conditions
User behavior during operating
Graz, 17.01.2014
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Central European Biomass Conference 2014
Materials & Methods
Field tests with three chimney stoves
■ Long term continuous measurements
■ Frequency of use of RWC
appliances
■ Operating conditions (flue gas
draught & flue gas temperature)
■ Measurements of emissions and
efficiency
■ Operation according to user
behavior
■ Operation according to
manufacturers manual
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Central European Biomass Conference 2014
Results
Survey - fuel
n Stoves
= 43
n Tiled stoves
= 34
n Residential biomass cookers = 37
Ʃn
■
Generally hardwood prefered for RWC
operation
Graz, 17.01.2014
Slide 7
= 114
■
Average length of used firewood either
25 cm or 33 cm
Central European Biomass Conference 2014
Results
Survey – Lighting mode
Lighting mode of RWC appliances – placement of lighting
batch
Option for
answer
Cross joint, on
top shavings
Firewood, at
the bottom
shavings
Cross joint,
without
shavings
Campfire
8%
58 %
15 %
19 %
Example
picture
Frequency of
answers
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Central European Biomass Conference 2014
Results
Survey – Lighting mode
■
Predominantlly small firewood pieces &
paper used for ligthing procedure
■
Usually ignition from the bottom/ bottom
third
 higher emissions (i.e. Nussbaumer et al. 2008: Particulate
Emissions from Biomass Combustion in
IEA Countries)
Graz, 17.01.2014
Slide 9
Central European Biomass Conference 2014
Results
Long term continuous field measurements for observation of use
Stove
Monitoring period
A
B
C
17.01.2013 –
24.01.2013
18.01.2013 –
22.01.2013
17.01.2013 –
12.02.2013
Average number of batches per
operation cycle
3
3
6
(min. 3 batches;
max. 4 batches)
(min. 2 batches;
max. 5 batches)
(min. 2 batches;
max. 16 batches)
Average duration of one batch
0.70 h
1.15 h
0.89 h
Average operation hours per day
0.9 h/d
5.2 h/d
7.0 h/d
■ High range of batches of one heating operation cycle („cold to cold“)
■ Average duration of one batch between 0.7h – 1.15h in real life operation
■ High range of average operation hours per day (< 1h – 7h per day)
Graz, 17.01.2014
Slide 10
Central European Biomass Conference 2014
Results
Operating conditions – Stove A
■ Trend of flue gas draught during one heating operation cycle
■ Chimney 1: Effective height: 6.0 m/ Design: Ceramic, insulated & rear
ventilated
26
28
29
29
25
18
0
0.5
1.0
1.5
2.0
Time (h)
Graz, 17.01.2014
Slide 11
2.5
3.0
3.5
Central European Biomass Conference 2014
Results
Operating conditions – Stove B
■ Trend of flue gas draught during one heating operation cycle
■ Chimney 2: Effective height: 3.4m/ Design: Ceramic, masoned
13
14
13.5
13
14.5
9
0
0.5
1.0
1.5
2.0
Time (h)
Graz, 17.01.2014
Slide 12
2.5
3.0
3.5
4.0
Central European Biomass Conference 2014
Results
Field measurements of emissions & efficiency
■ Comparison of different modes of operation:
■ Operation according to specific user behavior
■ Operation according to manufacturers manual
■ Main differences of operation:
■
■
■
■
Kind of used fuel (squared timber of spruce/ beech firewood)
Mode of lighting (bottom third/ top third)
Mode of recharging a new fuel batch
Mass of the fuel batches (~ 1.6 kg/ 2.2 kg)
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Slide 13
Central European Biomass Conference 2014
Results
Field measurements of emissions & efficiency
■ Comparison of different modes of operation:
Operation according to
user behavior
Lighting of stove
Recharging a new fuel
batch (Example)
Graz, 17.01.2014
Slide 14
Operation according to
manufacturers manual
Central European Biomass Conference 2014
Results
Field measurements of emissions & efficiency
■ Comparison of different modes of operation :
Results of field measurements respecting emissions (STP; 13 vol.-%
O2) and efficiency (indirectly calculated) of batch 1, 3 and 5
Stove C: Field measurements - Specific user behavior
Batch Duration
CO
OGC
PM
η
1
43 min.
7556 mg/m³ 1096 mg/m³
318 mg/m³
51.5 %
~ 1200 mg/m³
~ 8000 mg/m³
~ 200 mg/m³
3
39 min.
9491 mg/m³ 1351 mg/m³
141 mg/m³
29.1 %
5
39 min.
8059 mg/m³ 1320 mg/m³
125 mg/m³
42.5 %
Stove C: Field measurements – Manufacturers manual
1
32 min.
2546 mg/m³ 151 mg/m³
150 mg/m³
61.0 %
~ 2500 mg/m³
~ 250 mg/m³
~ 90 mg/m³
3
58 min.
3661 mg/m³ 239 mg/m³
63 mg/m³
42.0 %
5
45 min.
1993 mg/m³ 272 mg/m³
79 mg/m³
45.7 %
Stove C: Results of standard type test (STP; 13 vol.-% O2)
55 min
793 mg/m³
36 mg/m³
25 mg/m³
83.2 %
Graz, 17.01.2014
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Central European Biomass Conference 2014
Results
Impact of operating conditions on emissions and efficiency
Graz, 17.01.2014
Slide 16
Central European Biomass Conference 2014
Summary & Conclusions
■ Significant influence and effect of operating conditions as well as user
behavior regarding emissions and efficiency in real life operation.
■ RWC appliances still have a significant improvement potential in particular
in real life operation.
■ Results of current standard type tests reflect only best operation
performance
■ Results of current standard type tests for RWC appliances are hardly
realizable in real life operation (even when the appliance is operated
according to manufacturers manual)
There is a need to develop new test methods for RWC appliances
which – once implemented as standard – should be capable of
leading to further technological innovation and improvement and
finally to a satisfaction of future market and legal requirements.
Graz, 17.01.2014
Slide 17
Central European Biomass Conference 2014
Acknowledgements
■ The study was done in the frame of the project „Stove Testing 2020“
■ Funding bodies
■ Company partners
■ Scientific partners
Graz, 17.01.2014
Slide 18
Thank you for attention
Gabriel Reichert
Junior Researcher
Combustion Systems
BIOENERGY 2020+
Location Wieselburg
Tel: +43 7416 52238 73
gabriel.reichert@bioenergy2020.eu
Graz, 17.01.2014