measuring the filtration efficiency and particle indoor outdoor concentration ratio by tapio...
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MMEA Project Measuring the filtration efficiency and particle indoor/outdoor concentration ratio Aimo Taipale, Tapio Kalliohaka, Hannu Salmela, Jari Kataja and Matti Niemeläinen VTT Technical Research Centre of Finland
2 10/06/15 2
VTT Clean Air Solutions
§ Active research areas § Fine particle exposure control § Electrical air filtration technologies § Improving the indoor air quality (IAQ) and building protection § Automotive cabin air filtration § Power plant combustion air filtration § Clean production systems
§ 研究热点 § 颗粒物暴露控制 § 空气电子过滤技术 § 室内空气品质与建筑的保护 § 汽⻋车⻋车内空气过滤 § 发电厂燃烧空气过滤 § 清洁生产制度
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Introduction
§ Improving the indoor air quality (IAQ) is considered to be one of the most efficient way to enhance people´s health and wellbeing in terms of reducing human exposure to fine particles (PM 2.5).
§ The indoor concentration is affected mainly by § Outdoor concentration § Efficiency of supply air filtration § Leakage of the building envelope § Air exchange rate § Indoor sources § Using of room air cleaners
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VTT´s test system in Beijing in the Finnish Embassy residence building
§ Indoor air measurement system was installed in an air handling unit (AHU) in the residence of the Finnish Embassy in October 2014
§ Measurement devices: § Optical particle counter Met One 237 B: Single particles from 0.3 µm § Aerosol photometer TSI Dust Trak: Total mass concentration § Pegasor PPS § Vaisala temperature, humidity and CO2 sensors
§ Four sampling points: § Outdoor air § Mixed air (upstream of the filter) § Supply air (Downstream of the filter) § Return air (average indoor air)
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Measuring principle of air handling unit (AHU)
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User interface of the measuring system
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Filtration set-up in AHU 4: Normal filters
Normal filter set-up consist of Coarse pre-filters (right side) and F7 glassfibre bag filters (left side). Pressure drop of the filter set-up was 60 Pa
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Filtration set-up in AHU 4: Electret filters
In electret filter set-up pre-filters were replaced with corona wire charger and bag filters with LIFA 3G electret filters. Pressure drop was 30 Pa
Wire charger assembly: 6.8 kV and 1.18 mA
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Results
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Particle mass concentration (relative)(normal filters)
21.10. 22.10. 23.10. 24.10. 25.10. 26.10. 27.10. 28.10. 29.10. 30.10.
10
20
30
40
50
60
70
80
90
100
Date
Rela
tive
mas
s co
ncen
tratio
n (%
)
DT OUTDT RETDT MIXDT FILT
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Filtration efficiency and I/O ratio vs. time (normal filters)
21.10. 22.10. 23.10. 24.10. 25.10. 26.10. 27.10. 28.10. 29.10. 30.10.0
50
100Ef
ficie
ncy
(%)
21.10. 22.10. 23.10. 24.10. 25.10. 26.10. 27.10. 28.10. 29.10. 30.10.0
0.5
1
1.5
2
I/O R
atio
Date
0,390,590,841,413,16
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Filtration efficiency and I/O ratio vs. time (electret filters)
03.02. 04.02. 05.02. 06.02. 07.02. 08.02. 09.02. 10.02. 11.02.0
50
100Ef
ficie
ncy
(%)
03.02. 04.02. 05.02. 06.02. 07.02. 08.02. 09.02. 10.02. 11.02.0
0.5
1
1.5
2
I/O R
atio
Date
0,390,590,841,413,16
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CO2 concentration
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I/O ratio and outdoor PM10 concentration
0
100
200
300
400
500
600
700
800
0.00E+00
2.00E-‐01
4.00E-‐01
6.00E-‐01
8.00E-‐01
1.00E+00
1.20E+00
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2/3/2015 2:41
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2/6/2015 1:48
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2/7/2015 3:59
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2/8/2015 0:56
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2/10/2015 0:05
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2/11/2015 2:17
Outdo
or air pa
r+cle consen
tra+
on PM10 μ
g/m
3
I/O ra
+o
Date & Time
I/O ra6o
PM 10
premises overpressurised (-‐6 Pa) -‐> (4 Pa)
premises pressure returned to normal (4 Pa) -‐> (-‐6 Pa)
Air0 room air cleaner switched on
Air0 room air cleaner switched off
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Supply air filter efficiencies
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Loaded filter (12.5.2015)
Electret filter has now been used for 14 weeks. Pressure drop has increased from 30 Pa to 53 Pa and charger voltage has increased from 6.8 kV to 7.7 kV. Slow pressure drop increase indicates that changing interval of the filter is more than 6 months. Increase in charger voltage indicates that corona wires are slighly contaminated
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Residency monitoring system installed in the residence hallway
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Main findings at residence building measurements (1)
§ HVAC system at recidence building provides an excellent platform for piloting new filtration solutions
§ The measurement system worked OK and the results proofed that indoor air particle concentration can be reduced significantly
§ The screen at hallway enables presenting the data on-line § Installing more efficient supply air filters (Lifa Air) resulted
extremely low particle concentrations in supply air § Particle Indoor/Outdoor concentration ratio is not as good as the
HVAC system would enable
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Main findings at residence building measurements (2)
§ Overpressurizing the building proofed that leakages through the building envelope is the main indoor impurity source
§ Recirculating room air cleaner reduced the concentration further, dimensioning the clean air delivery rate must be emhasized
§ The HVAC system uses a lot of recirculation, it can be seen in high CO2 values during dense occupation.
§ In the future PM2.5, CO2 and energy consumption should be optimized simultaneously in HVAC control system
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