Ambient air filter efficiency in airtight, highly energy efficient dwellings – A simulation study to evaluate

benefits and associated energy costs

Gabriel Rojas, University of Innsbruck, Austria

Unit for Energy Efficient Buildings

October 16th, AIVC 2019

Performed in the framework of IEA EBC Annex 68

Seite 2

Motivation

What is the exposure contribution from outdoor originatedand from indoor originated particulate matter?

What filter quality is recommendable?

What impact has the use of a recirculating vs. extractingcooker hood?

In very airthight residential housing with MVHR (Passive Houses)…

Simulation study (CONTAM) accounting…filter efficiencyenvelope penetrationparticle depositionoutdoor air concentrationindoor sources

= 𝑓 (𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒 𝑠𝑖𝑧𝑒)21 size bins

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Seite 3

Model assumption – Reference apartment

Living room (LR)incl. kitchen (Ki)

30.2 m²

Child’s room (CR)

10.4 m²

Bedroom (BR)

12.9 m²

Entrance / hallway15.3 m²

Bath(BA)

7.2 m²

Balcony

N

adjacent apartment

adja

cent

apar

tmen

t

Ambient

Foto: Aerex Haustechniksysteme

Exhaust

Supply

Extract

Seite 4

Model assumption – Ambient air PM concentration

Derived from:Ruprecht, Jaenicke. 1993. “Tropospheric Aerosols.” Pp. 1–31 in

Aerosol-Cloud-Climate Interactions, edited by P. Hobbs. Academic Press

PM2.5

Low 8.4 µg/m³

Ref 42 µg/m³

High 84 µg/m³

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Seite 5

Model assumption – Ambient air PM concentration

Ort I Name I Datum

Source: https://www.who.int/gho/phe/air_pollution_pm25_concentrations/en/

Seite 6

Model assumptions: filter, penetration, depositionFilter efficiency Envelope penetration

Particle deposition

Derived from: Riley et.al. (2002). “Indoor Particulate Matter of Outdoor Origin: Importance of Size-Dependent Removal Mechanisms.” Environmental Science and Technology 36(2):200–207.

Derived from: Shi, Bingbing. 2012. “Removal of Ultrafine Particles by Intermediate Air Filters in Ventilation Systems - Evaluation of Performance and Analysis of Applications Ventilation Systems.” Chalmers University of Technology, Göteborg, Sweden.

Derived from: Liu, De Ling and William W. Nazaroff. 2003. “Particle Penetration through Building Cracks.” Aerosol Science and Technology 37(7):565–73.

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Seite 7

Model assumptions: Cooking source strength

bre

akfa

stlu

nch

din

ner

Seite 8

Results: Daily evolution

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8

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Results: Daily evolution

Night time

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Results: Daily evolution

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Results: Daily evolution

After frying burger

Seite 12

Results: Daily evolution

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Seite 13

Results: Exposure reduction vs. electr. fan power

M5 M6 F7 F8 F9

MERV9/10 MERV11/12 MERV13 MERV14 MERV15

Seite 14

Results: Relative to extract air ventilation

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Sensitivity on model assumptions

Ort I Name I Datum

Reference Low High

Bed- / child’s room door opening 8am – 10pm 4 x 10 min 0-24 hrs

Window opening (tilted): all 3.6 h/day 0 h/day 6.3 h/day

Kitchen area 3 x 20 min - 3 x 35 min

Living room area 3 x 10 min - 3 x 18 min

Bedroom 2 x 56 min - 2 x 98 min

Childs room 2 x 6 min - 2 x 11 min

Airtightness / n50 0.6 1/h 0.3 1/h 1.5 1/h

Deposition rate multiplier 1 0.33 3.0

Penetration factor for crack with

dimensions

W 0.25 mm x

L 9.4 cm

- W 0.25 mm x

L 4.3 cm

Seite 16

Results: Outdoor vs indoor source strength

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Recommendations for airtight residential housingwith MVHR / Passive Houses

• F7 (ePM1-50% / MERV 13) can be considered a good general recommendation. However, higher quality (F9) are recommended for moderate or high polluted areas.

• Extracting cooker hoods are advisable for household where high cooking induced particle generation (e.g. frying) can be expected. However, in areas with high outdoor pollution, PM introduced with make-up air will be a (more) relevant source.-> Further product development is encouraged.

• Recirculating cooker hoods will not notably reduce total PM exposure.-> Further product development is encouraged.

Seite 18

Outlook / Further research

• Apply time-resolved recent ambient air data for simulation• Apply more diverse indoor generation models• Apply resuspension models• Eperimental validation

• Measure / apply (fractional) filter efficiency for filter class acc. to ISO 16890

• Account for potentially different health effects from outdoor originated vsindoor generated particles.

Thank you!

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Seite 19

Model assumptions: PM deposition

Ort I Name I Datum

Source: Riley et.al. (2002). “Indoor Particulate Matter of Outdoor Origin: Importance of Size-Dependent Removal Mechanisms.” Environmental Science and Technology 36(2):200–207.

Footer

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cooking

filterPM measurement

𝑅𝐸 = 1-∆𝐶𝑤𝑖𝑡ℎ𝐹𝑖𝑙𝑡𝑒𝑟

∆𝐶𝑤𝑖𝑡ℎ𝑜𝑢𝑡

Ventilation chamber(100 m³/h)

Measurement method: cooking source strength

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Deriving cooking source strength

Ort I Name I Datum

𝑚 = න0

𝑝𝑒𝑎𝑘

𝐴𝐸𝑅 𝑉 𝑐 𝑑𝑡 + 𝑉 𝑐

100

101

102

103

104

0

0.5

1

1.5

2x 10

5

dN

/dlo

gD

p [#

/cm

³]

Particle diameter [nm]

Onion_Jan25-31_200C_100m3h_Broan

100

101

102

103

104

0

50

100

150

200

250

dM

/dlo

gD

p [µ

g/m

³]

Particle diameter [nm]

Onion_Jan25-31_200C_100m3h_BroanVerteilung der Partikelanzahl Verteilung der Partikelmasse

PM2.5 PM2.5

Filter Br1-2, gemessen mit SMPS 3936 (10-400nm) und OPS 3330 (0,3 -10µm), 3 Wiederholungen

Größenverteilung der Partikel: Zwiebel @ 200 C

UFP UFP

ohne Filter

gebr. Filter: 37%

neuer Filter: 54%25%

30%

60%

65%

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101

102

103

104

0

5

10

15x 10

5

dN

/dlo

gD

p [#/c

m³]

Particle diameter [nm]10

110

210

310

40

200

400

600

dM

/dlo

gD

p [µ

g/m

³]Particle diameter [nm]

Burger-M1_Jan26-30_200C_100m3h_Br

UFPPM2.5

UFPPM2.5

Filter Br1-2, gemessen mit SMPS 3936 (10-400nm) und OPS 3330 (0,3 -10µm), 2-3 Wiederholungen

Verteilung der Partikelanzahl Verteilung der Partikelmasse

ohne Filter

gebr. Filter: 16%

neuer Filter: 25%

68%70%

4%21%

Seite 24

Results: Outdoor vs indoor source strength

Ort I Name I Datum

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