Upload
lykien
View
215
Download
2
Embed Size (px)
Citation preview
ENERGY TECHNOLOGIES AREA ENERGY ANALYSIS AND ENVIRONMENTAL IMPACTS D IV ISION
Characterizing Formaldehyde
Emissions from Home Central
Heating and Air Conditioning Filters
Hugo Destaillats, Marion L. Russell, William J. Fisk
Lawrence Berkeley National Laboratory
Indoor Environment Group
1
CARB Contract 14-303
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Acknowledgement
Qunfang (Zoe) Zhang and Peggy Jenkins (CARB)
Toshifumi Hotchi, Brett Singer (LBNL)
Technical Advisors: Wenhao Chen, Thomas Justice, Thomas Kuehn, Drew Williams and Harinder Singh
The statements and conclusions in this report are those of the Contractor (LBNL) and not necessarily those of
the California Air Resources Board.
The mention of commercial products, their source, or their use in connection with material reported herein is not to be construed
as actual or implied endorsement of such products.
2
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
We spend >90% time indoors
Indoor air: different chemical mixture than outdoor air
Higher indoor VOC concentrations (~10 to 1000 times)
Close proximity with sources in enclosed environment, leading to a higher intake than in outdoor air
Multiple pollutant sources
Indoor pollutant sources and concentrations
4
Occupant activities (smoking, cooking, cleaning)
Occupants (bioeffluents, personal care products)
Outdoor air
Building materials and furnishings
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Formaldehyde is a key indoor contaminant
Carcinogen (WHO-IARC, US-EPA, CA-Proposition 65)
Irritation of eyes, respiratory system
Ubiquitous in buildings (residential > commercial)
Levels often exceed reference exposure levels (RELs)
Easy to measure – large amount of data available
Difficult to remove with most air cleaning technologies
Formaldehyde concentration (µg m-3)
0 20 40 60 80 100 120 140
100
80
60
40
20
0
Cu
mu
lati
ve f
req
uen
cy (
%)
Indoor (n=105)Outdoor (n=39)
Median indoor conc.36 µg m-3 (29 ppb)
Adapted from: Offermann, 2009 CARB/CEC Report
>95% of indoor samples above OEHHA chronic REL 9 µg m-3 (7 ppb)
25% of indoor samples above OEHHA acute REL
55 µg m-3 (43 ppb)
C
O
H H
5
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
What are the main indoor formaldehyde sources?
Multiple indoor sources
High emitters: materials containing urea-formaldehyde polymers
(wood products) fiberglass insulation and ceiling tiles
California regulation (ATCM 93120, 2008) established emission standards for composite wood products: hardwood plywood (HWPW), particleboard (PB), and medium density fiberboard (MDF)
France (2012): mandatory labeling of building products, based on pollutant emissions
Fiberglass HVAC filters also contain urea-formaldehyde binders
6
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Hydrolytic depolymerization of urea-formaldehyde resin
7
O
N H
N
O
NH O
N H
N
HO
R1
O
HN
H
R2
H2O
O
N H
N
O
NH O
N H
N
HO
R1 HO
HN
H
R2 OH
O
N H
NH
HO
R1
+ CH2O
O
NH O
N H
N
H2N
H
R2
+ CH2O
60 oC96% RH3 months
Brown, 1990 Polymer Degradation & Stability
Degradation of UF foam insulation
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Recent evidence: filters used in commercial buildings
Two unoccupied offices (Zones 1 and 2), serviced by identical HVAC units
Alternating synthetic and fiberglass filters
RH: 50% or 80% (humidifier)
Formaldehyde concentrations were higher when fiberglass filters were used, and at high relative humidity
Are fiberglass residential filtersa substantial source of formaldehyde?
8
Sidheswaran et al, 2013 Environ. Sci. Technol.
HVAC #1
Supply
Zone 2Zone 1
HVAC #2
ReturnReturn
■ Synthetic filter■ Fiberglass filter
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Selection of filters used in this study
Five experts from industry, academia and government joined Project Advisory Committee (PAC)
Input from PAC: In general, low cost MERV 7 or lower filters are resin-bonded, and use urea-
formaldehyde (UF) resin.
Formaldehyde emissions can be affected by the curing conditions of the UF resin
High-end fiberglass filter media, mostly for commercial buildings, uses phenol-formaldehyde binders
Unlikely formaldehyde sources: HEPA filters; cardboard/chipboard frame and glues; tackifier used as coating to increase particle arrestance
Criteria for filter selection: Inclusion of at least one fiberglass filter from each of the three North American
manufacturers.
Inclusion of synthetic filters from at least two manufacturers with a significant presence in the US market
Inclusion of additional fiberglass filter samples, retrieved directly from the production line of several manufacturers.
10
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Filters purchased from online retailers
11
No. Manufacturer MediaMERV Rating
Description of filtration media
1 A FG na fiberglass media with light adhesive2 A FG MERV 4 fiberglass media with adhesive3 A FG MERV 4 fiberglass media with adhesive
4 B FG MERV 4fiberglass and polyester fibers
with gel adhesive5 B SYN MERV 11 synthetic filter media, pleated6 B SYN MERV 4 polyester fibers7 B SYN MERV 8 synthetic pleated filter media
8 C FG MERV 4fiberglass media,
continuous filament spun glass
9 C FG nafiberglass media,
continuous filament spun glass
10 D SYN nasynthetic media, electrostatic,
allergen reduction filter, pleated
11 D SYN MERV 8synthetic media, electrostatic,
allergen reduction filter, pleated
FG: Fiberglass SYN: synthetic
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Fiberglass filters retrieved from production line
12
SampleManufacturer of
Commentsfilter media
a A AThicker fiberglass media than those typically
used for residential buildings.
b A AThicker fiberglass media than those typically
used for residential buildings.c C X Relatively recent productiond C X Relatively recent productione A A Sample is at least 5 years oldf C Z Relatively recent productiong C Z Relatively recent productionh C Z Relatively recent production
i Unknown Unknown Imported from China
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Experimental setup used in bench-scale tests
13
Tested filters
Upstream sampling port
Downstream sampling port
Vent
Logging system
Heating plate
Upstream air internal inlet
Teflon tubingDownstream air internal outlet
MFC
MFC
House air
HEPA filter
Activated carbon filter
Water bubbler
T, RH sensors
200–L chamber
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Bench-scale test chamber
14
Air flows from
bottom to top
Air outlet Air inletSampling
ports
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Experimental setup used in room-sized chamber tests
15
Humidifier #3
Upstream sampling port
Chamber exhaust
Logging system
Outdoor air
Activated carbon + chemisorbent bed
T, RH, CO2
sensors
20–m3 chamber
Custom-made filter
holder
Downstream sampling port
Humidifier #1
Humidifier #2
RH controller
Fan
Recirculation loop
Variable speed fan
Iris damper
Flexible ductwork (ending opposite side of chamber)
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Exterior view of room-sized chamber
16
20-m3 chamber
upstream
Sampling ports
Variable-speed fan
Custom-built filter holder
Iris damper
downstream
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Interior view of room-sized chamber
17
From external loop
Three home humidifiers
Fan
To external loop
Humidity Controller
door
From external loop
Three home humidifiers
Fan
To external loop
Humidity Controller
door
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Formaldehyde sampling and analysis
Method EPA TO-11A (1999)
Sampling
collection using dinitrophenyl hydrazine (DNPH)-coated silica samplers (Waters)
simultaneous upstream/downstream sampling
flow: 1 L min-1 ± 1% over 1 hour for V = 6 L
Analysis
Samplers were extracted with 2 mL acetonitrile
Analyzed by HPLC with UV detection at 360 nm
Calibration curve using authentic standards of the corresponding DNPH hydrazone derivative
Limit of detection < 0.1 μg m-3
18
[H+] - H2O
+
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
0 0
182
99
165
84
166
92
0
40
80
120
160
200
24 h 48 h
ΔC
(p
pb
) chamber blankFG - sample cFG - sample dFG - sample g
0 0
122 119
5139
2821
42 38
3.7 2.84.0 3.00
20
40
60
80
100
120
140
24 h 48 h
ΔC
(p
pb
)
chamber blank
FG - sample 3 (A)
FG - sample 9 (C)
FG - sample 4 (B)
FG - sample 1 (A)
SYN - sample 11 (D)
SYN - sample 5 (B)
Formaldehyde concentration in bench-scale chamber
20
blank blank
blank blank
Fiberglass and synthetic
filters purchased
from retailers
Fiberglass filters from production
line
RH = 62 – 64 %
RH = 62 – 64 %
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Relative change from 24-h to 48-h sample (63% RH)
21
Fiberglass and synthetic
filters purchased
from retailers
Fiberglass filters from production
line
2.5
24 24
9
2326
0
5
10
15
20
25
30
Dec
reas
ed b
etw
een
2
4h
an
d 4
8h
sam
ple
(%
)
FG - sample 3 (A)
FG - sample 9 (C)
FG - sample 4 (B)
FG - sample 1 (A)
SYN - sample 11 (D)
SYN - sample 5 (B)
4649
45
0
10
20
30
40
50
60
Dec
reas
ed b
etw
een
2
4h
an
d 4
8h
sam
ple
(%
)
FG - sample c
FG - sample d
FG - sample g
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
122
98
1633
119
84
30
0
20
40
60
80
100
120
140
64% (Jul '15) 64% (Jan '16) 16% (Jan '16) 34% (Jan '16)
ΔC
(pp
b)
Average Relative Humidity
Filter 3 (A)
24 h
48 h
51
14
4.2
39
13
3.6
0
10
20
30
40
50
60
63% (Ago '15) 62% (Feb '16) 33% (Feb '16)
ΔC
(p
pb
)
Average Relative Humidity
Filter 9 (C)
24 h
48 h
Effects of filter aging and relative humidity
22
Some FG filters emitted lower formaldehyde after 6 month storage
All FG filters emitted significantly less formaldehyde when RH was reduced from 62-64% to 32-34%
20 – 30 % loss
65 – 75 % loss2830
8.2
21
26
5.3
0
5
10
15
20
25
30
35
62% (Aug '15) 64% (Mar '16) 32% (Mar '16)
ΔC
(pp
b)
Average Relative Humidity
Filter 4 (B)
24 h
48 h
64% (Jul ‘15) 64% (Jan ‘16) 16% (Jan ’16) 34% (Jan ‘16)
Average Relative Humidity
62% (Aug ‘15) 64% (Mar ‘16) 32% (Mar ‘16)
Average Relative Humidity
65 % lower
63% (Aug ‘15) 62% (Feb ‘16) 32% (Feb ‘16)
Average Relative Humidity
70 % lower70 – 80 % lower
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
98
46
34
84
47 44
0
10
20
30
40
50
60
70
80
90
100
Full filter Media only Frame only
ΔC
(p
pb
)
Filter 3 (A)
24 h
48 h
Filter media vs. frame: both were comparable sources
23
47 – 56 % 35 – 53 %
34 – 38 % 35 – 40 % 79 – 85 % 58 – 60 %
Roughly equal amounts of formaldehyde were emitted from the media and the frame
When compared with full filter, approximate mass balance was reached
30
10.2 12
26
9.9 9.0
0
5
10
15
20
25
30
35
Full filter Media only Frame only
ΔC
(pp
b)
Filter 4 (B)
24 h
48 h
14
11
8.4
1311
7.6
0
2
4
6
8
10
12
14
16
Full filter Media only Frame only
ΔC
(p
pb
)
Filter 9 (C)
24 h
48 h
Full filter Media only Frame only Full filter Media only Frame only
Full filter Media only Frame only
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Formaldehyde concentration in room-sized chamber
24
Striped bars: 400 cfm
(face velocity 0.5 m s-1)
Solid bars:
1000 cfm
(face velocity 1.3 m s-1)
4.03.6 3.5 3.6
4.03.4
4.1
4.8
6.76.3
6.67.1
3.3
4.0
5.0
3.7
0
1
2
3
4
5
6
7
8
Co
nce
ntr
atio
n (
pp
b)
36 - 46 % RH
FG - sample 3 (A) FG - sample 4 (B) FG - sample 9 (C)
chamber background
SYN - sample 11 (D)
24 2623 23
1316
2023 24
30
51 52
6.8 5.5 6.8 6.8
0
10
20
30
40
50
60
Co
nce
ntr
atio
n (
pp
b)
68 - 72 % RH
chamber background
FG - sample 3 (A) FG - sample 4 (B) FG - sample 9 (C) SYN - sample 11 (D)
24
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Additional measurements were needed for two FG filters
25
1316
2023
18
30
0
5
10
15
20
25
30
35
Co
nce
ntr
atio
n (
pp
b)
FG - sample 4 (B), 69 - 72 % RH
original data additional results
chamber background
2430
51 52
26
46
70
62
51 50
0
10
20
30
40
50
60
70
80
Co
nce
ntr
atio
n (
pp
b)
FG - sample 9 (C), 69 - 72 % RH
original data additional results
chamber background
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Formaldehyde emission rates at moderate RH
FG: 60 – 300 µg h-1 m-2
SYN: 60 – 180 µg h-1 m-2
26
90 75 87 920
50
100
150
200
E F(µ
g h
-1m
-2)
FG - sample 3 (A)
400 cfm 1000 cfm
86 62 114 1560
50
100
150
200
E F(µ
g h
-1m
-2)
FG - sample 4 (B)
400 cfm 1000 cfm
213 191 266 2960
100
200
300
400
E F(µ
g h
-1m
-2)
FG - sample 9 (C)
400 cfm 1000 cfm
60 98 185 1020
50
100
150
200
250
E F(µ
g h
-1m
-2)
SYN - sample 11 (D)
400 cfm 1000 cfm
EF =ΔC x Vchamber x λchamber
Afilter
Room-sized chamber
Vchamber = chamber volumeλchamber = chamber air exchange rateAfilter = area of filter
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Formaldehyde emission rates at high RH
FG: 500 – 4000 µg h-1 m-2
SYN: 100 – 220 µg h-1 m-2
27
993 1054 1153 11520
500
1000
1500
E F(µ
g h
-1m
-2)
FG - sample 3 (A)
400 cfm 1000 cfm
456 587 958 1099 862 15240
500
1000
1500
2000
E F(µ
g h
-1m
-2)
FG - sample 4 (B)
400 cfm 1000 cfm
990 1264 2915 2976 1346 2528 3914 3449 2891 28240
1000
2000
3000
4000
5000
E F(µ
g h
-1m
-2)
FG - sample 9 (C)
400 cfm 1000 cfm
165 102 223 2210
50
100
150
200
250
300
E F(µ
g h
-1m
-2)
SYN - sample 11 (D)
400 cfm 1000 cfm
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
How do our results compare with others?
29
0.1
1
10
100
1000
10000
100000
BUF CUF PP DL FG BPF P LowRH
HighRH
LowRH
HighRH
FG -LowRH
FG -HighRH
SYN -HighRH
FG -LowRH
FG -HighRH
SYN -HighRH
Form
ald
ehyd
e em
issi
on
rat
e (µ
g m
-2h
-1)
Kelly et al, 1999 - ES&TSidheswaran
et al, 2013 - ES&T
Low face velocity
High face velocity
This work
Low face velocity
(bench scale)
High face velocity
(room scale)
Various building materialstested at 50 % RH
FG HVAC filters for commercial buildings
HVAC filters for residential buildings
Bar
e U
F w
oo
d p
rod
s.
Fab
rics
Co
ated
UF
wo
od
pro
ds.
Lam
inat
es
Bar
e P
F p
rod
s.
Pap
er
FG p
rod
s.
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Impact of FG filters was predicted in three scenarios
HOME ARB 1 ARB 2 ARB 3
74 m2 (800 ft2) apartment
140 m2 (1500 ft2) house
325 m2 (3500 ft2)2-story house
Indoor space volume (m3)
182 343 796
Filter(s) used 12“ x 24” 18” x 24” 24” x 24”12” x 24”24” x 24”
Two24” x 24”
Three24” x 24”
Total filter surface area (m2)
0.18 0.27 0.36 0.54 0.72 1.08
Φ (x 10-3) 2.4 3.6 2.6 3.9 2.4 3.6
area floor home
area surfacefilter ΔC =
EF x Afilter
Vhome x λhome
Vhome = indoor space volumeλhome = home air exchange rate
30
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Contribution to indoor formaldehyde (24/7 operation)
31
RH = 40% ; λ= 0.2 h-1
ARB 1
Lower Φ
RH = 70% ; λ= 0.2 h-1 RH = 70% ; λ= 0.5 h-1
ARB 1
Higher Φ
ARB 2
Higher Φ
RH = 40% ; λ= 0.2 h-1 RH = 70% ; λ= 0.2 h-1 RH = 70% ; λ= 0.5 h-1
RH = 40% ; λ= 0.2 h-1 RH = 70% ; λ= 0.2 h-1 RH = 70% ; λ= 0.5 h-1
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Some building designs require HVAC continuous operation for mechanical ventilation/particle filtration
In all other (most) cases, HVAC systems follow duty cycles
Model to calculate the fraction of time during which HVAC system operates adaptedfrom Logue et al (2012).
Based on linear correlationof time fraction andΔT between outdoor air and thermostat setting:
Heating: 18 oC (65 F)
Cooling: 26 oC (78 F)
32
Establishing the HVAC duty cycle for different climates
new homes
old homes
average
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Eight representative CA climate zones were evaluated
33
San Francisco(CZ 3)
Los Angeles (CZ 6)
Stockton(CZ 12)
Riverside(CZ 10)
Fresno(CZ 13)
Browley(CZ 15)
Bishop(CZ 16)
Eureka(CZ 1)
Warmest summers
Coldest winters
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Climate zone 16: Bishop
34
DUTYCYCLE
Heating (January)
Cooling (July)
Min T 67% -
Average T 37% 4%
Max T 10% 66%
Source: PG&E Guide to California Climate Zones - 2017 https://www.pge.com/myhome/edusafety/workshopstraining/pec/toolbox/arch/climate/index.shtml
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Predicted time fraction for HVAC operation
35
CA climate
zoneCity
Heating season Cooling season
MonthTemp. (oC)
Hourly time fractional Month
Temp. (oC)Hourly time
fractional
min mean min mean mean max mean max
1 Eureka JAN 5.0 8.9 41% 26% SEP 13.3 16.7 8%*
3 SF JAN 6.1 8.9 37% 26% SEP 17.8 22.8 8%
6 LA JAN 7.8 12.8 30% 10% AUG 20.5 24.4 15%
10 Riverside JAN 4.4 11.7 44% 15% JUL 20.0 34.4 55%
12 Stockton JAN 2.8 7.2 50% 32% JUL 24.4 35.0 15% 57%
13 Fresno JAN 2.8 7.8 50% 30% JUL 27.2 36.7 26% 63%
15 Browley JAN 3.9 12.8 50% 14% JUL 32.8 42.2 39% 77%
16 Bishop JAN - 6.7 3.3 67% 37% JUL 24.4 36.7 4% 66%
* due to heating during the summer
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Outdoor air is unlikely to generate high indoor RH
Winter: very high outdoor RH (at low T) correspond to moderate contributions to indoor RH (only 15 – 40 % RH)
Summer: moisture in outdoor air condenses at the AC unit; liquid water is drained out of the system
Indoor moisture sources play a very important role
36
Sources of indoor moisture
Activity EH2O (L day-1)
5-min shower (x4) 1.0Cooking on gas range 2.4Dishwashing 0.5Floor mopping 3.0House plants 0.4Respiration / perspiration 5.0TOTAL 12.3
HomeAir exchange
rate (h-1)RH (%)
@ 65 F @ 78 F
ARB 10.2 80 500.5 32 20
ARB 20.2 45 250.5 18 10
ARB 30.2 20 100.5 8 4
Contribution of residential moisture sources
estimated for a family of four members
(adapted from Trechsel et al, 1994)
Indoor relative humidity from residential moisture
sources, neglecting contributions from outdoor
air and moisture removal by different sinks
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
High outdoor RH does not translate into high indoor RH
37
Fresno, Stockton
Riverside
Bishop
Browley
Los Angeles, San Francisco
70% RH 40% RH
Eureka
Psychrometric chart
January
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Family of four
ARB 1 home; λ = 0.2 h-1; winter thermostat setting (18 oC, 65 F)
Duty cycle corresponding to January in each climate zone
Considering only indoor moisture sources, no sinks
Values correspond to emission rates from all tested FG filters
38
Predicted indoor formaldehyde concentrations (i/ii)
9.3
1.1
8.1
0.94
7.6
0.88
6.4
0.75
6.4
0.75
3.7
0.43
3.6
0.41
2.6
0.30
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
Bishop (37%) Stockton (32%) Fresno (30%) Eureka (26%) San Francisco(26%)
Riverside (15%) Browley (14%) Los Angeles(10%)
Δ[F
orm
ald
eh
yde
] (
pp
b)
Prop 65 NSRL
OEHHA Chronic REL
Worst-case scenario OEHHA Chronic REL
Prop 65 NSRL
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
39
Predicted indoor formaldehyde concentrations (ii/ii)
0.70
0.15
0.62
0.13
0.57
0.12
0.49
0.10
0.49
0.10
0.28
0.06
0.27
0.06
0.19
0.04
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
Bishop (37%) Stockton (32%) Fresno (30%) Eureka (26%) San Francisco(26%)
Riverside (15%) Browley (14%) Los Angeles(10%)
Δ[F
orm
ald
ehyd
e] (
pp
b)
Family of four
ARB 2 home; λ = 0.2 h-1; winter thermostat setting (18 oC, 65 F)
Duty cycle corresponding to January in each climate zone
Considering only indoor moisture sources, no sinks
Values correspond to emission rates from all tested FG filters
Typical scenario
ENERGY TECHNOLOGIES AREA ENERGY ANALYSIS AND ENVIRONMENTAL IMPACTS D IV ISION
CONCLUSIONS
AND PERSPECTIVES
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Residential FG filters emit formaldehyde in contact with humidified air (>> synthetic filters) Consistent w/ previous results in commercial buildings
Emissions were observed from media AND frame
In most cases, FG filters can increase indoor formaldehyde concentrations by only a few ppb
Emissions can impact IAQ more severely in a subset of conditions (high occupancy, low air exchange rate, smaller spaces, extreme weather, varying by location) Exceeding OEHHA Chronic REL in three areas simulated
Source-control strategies may include: Replacing urea-formaldehyde polymers used as binders for FG
Replacing FG filters by other low-emitting filters
Both solutions may be limited by cost barriers
Summary of findings
41
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
A limited set of experimental conditions was evaluated (number and types of filters, face velocity, etc)
Only two indoor RH settings were considered: moderate (35 -45%) and high (62 -72%).
Eight climate zones were considered, comprising most of the State’s population. Effects could be more severe in other parts of the USA with more extreme climates.
Tests were carried out over short periods of time (initial conditions) using clean laboratory air. What about longer exposure periods?
Study was carried out using only unexposed filters… what about used filters? What is the effect of “filter cake”?
Limitations of the study
42
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Hints from a previous study…
“Filter cake” can contribute to additional formaldehyde emissions, by:
Serving as a moisture reservoir in direct contact with the fiberglass media, and/or
Becoming another formaldehyde source
43
Formaldehyde concentration measured downstream of FG filter @ 50% RH.
• LBNL: 3 month of use in an LBNL building (outdoor particles mostly influenced by vegetation)
• POAK: 3 months of use at the Port of Oakland (outdoor particle mostly diesel emissions, freeway traffic).
Destaillats et al, 2011 – Atmos. Environ.
E NE R G Y T E C HNO L O GIE S A R E A E NE R G Y ANAL Y S I S AND E NV I R O NME NT AL I M P ACT S D I V I S I O N
Literature citedDestaillats, H., W. Chen, M. G. Apte, N. Li, M. Spears, J. Almosni, G. Brunner, J. Zhang and W. J. Fisk. 2011. "Secondary pollutants from ozone reactions with ventilation filters and degradation of filter media additives." Atmos. Environ. 45: 3561-3568.
Kelly, T. J., D. L. Smith and J. Satola. 1999. "Emission rates of formaldehyde from materials and consumer products found in California homes." Environ. Sci. Technol. 33: 81-88.
Logue, J.M., W.J.N. Turner, I.S. Walker, B.C. Singer. 2012. "Evaluation of an incremental ventilation energy model for estimating impacts of air sealing and mechanical ventilation". LBNL Report 5796E. https://indoor.lbl.gov/publications/evaluation-incremental-ventilation
Offermann, F. J. 2009. "Ventilation and Indoor Air Quality in New Homes. ." California Air Resources Board and California Energy Commission, PIER Energy‐Related Environmental Research Program. Collaborative Report. CEC‐500‐2009‐085. http://www.arb.ca.gov/research/apr/past/04-310.pdf.
Sidheswaran, M., W. Chen, A. Chang, R. Miller, S. Cohn, D. Sullivan, W. J. Fisk, K. Kumagai and H. Destaillats. 2013. "Formaldehyde emissions from ventilation filters under different relative humidity conditions." Environ. Sci. Technol. 47: 5336-5343.
Trechsel, H.R., Editor. 1994. "Moisture Control in Buildings". ASTM Manual Series: MNL 18, American Society for Testing and Materials, Philadelphia, PA
US EPA. 1999. "Compendium Method TO-11ADetermination of Formaldehyde in Ambient Air Using Adsorbent Cartridge Followed by HPLC [Active Sampling Methodology]". Office of Research and Development, U.S. Environmental Protection Agency (U.S. EPA): Cincinnati, OH, 1999.
44
Thanks!