Labor for mass production of these units should require approximately 1/2

hr. The total cost for 7,812 units to cover the pond is $228,515, and
annual replacement cost for the polyethylene is $4,182. Installation on

the pond should require approximately 70 man-hours at $25/man-hour or
$3730. This gives an annual cost over a 10-year period at 8% interest of
39,980.

As discussed earlier, the primary function of the cooling pond is the
transfer and dissipation of waste heat. The raft proposed above creates
a dead-air space between the film and water surface which acts as an
effective thermal insulator, inhibiting both radiative and convective heat
transfer from the pond. This interferes severely with the cooling function
of the pond, and the power plant would require additional means for dis-
sipating its waste heat.

INJECTION WELLS

If the water necessary for operation of the power plant could be drawn
from the groundwater aquifer used to cool the condensers, and then rein-
jected into the aquifer, the ice fog problem associated with cooling ponds
would be completely eliminated. The problems associated with this tech-
nique are, however, generally unknown and require some experimentation.

In the early 1970's, the city of Fairbanks tried a water injection
well for disposal of heated water at the municipal power plant. The well
was dug into the gravel on the bank of the Chena River, and water was
injected into this well rather than being discharged into the river.
Problems developed almost immediately due to plugging of the injection
well, and the volume of water that could be forced into the well declined
considerably. The well was later abandoned as unusable (J. Movius,
personal communication, 1972).

Injection well plugging appears to be a problem that must be overcome
for this technique to be viable. This problem is particularly severe in
the Fairbanks area because of the high iron content of the groundwater -
The iron in the water also creates a problem for power plant operation
because it precipitates during the cooling process and tends to plug the
condenser tubes. '

Another problem that must be resolved is the legality of injecting
water into the groundwater aquifer. Alaska's statutes specifically pro-
hibit any contamination of the groundwater aquifers, and the aquifer in the
vicinity of the Ft. Wainwright power plant is used as the primary water
supply by many homes in the area. A legal opinion, which could be re-
latively complicated, would have to be obtained on this subject.

The above problems, however, do not appear to be insurmountable, with
the possible exception of the legal problem. Groundwater injection wells
have been operating for many years, and if properly constructed and oper-
ated, the plugging problem should be controllable by present technology.
The condenser plugging problem may require additional manpower for con-
denser cleaning; however, other than the additional cost, no technical

11


ee

APPENDIX B.

METEOROLOGICAL DATA.

TABLE B-l. FT. WAINWRIGHT COOLING POND METEOROLOGICAL DATA, 3 February-1 March 1976.
Average Relative humidity
Ta, /Ta, Tw, Tw, Tw, Windspeed Wind 1/4 mile upwind
Date Time °C °c °c °C (mph) (m/s) direction (4) Remarks
3 Feb 0830 -22/-2h ih ik 12 W 57 Accuracy probably no
1145 m/-21 2.5 1.1 SE 69 better than + 1°C
1600 -17/-21 13 13 Ik 1.9 0.8 NE 15
4 Feb 0830 m/-24 16 16 16 SE m Ta, = Air temp over pond
1145 m/-23 2.3 1.0 sw 3
1515 -19/-22 14 ih ak 2.1 0.9 NE 48
5 Feb 0815 m/-26 14 1h 12 N 10 Ta, = Air temp 1/4 mile
1130 m/-23 2.1 0.9 N 36 upstream
1545 m/-20 15 15 15 1.9 0.8 NN 59
6 Feb 0815 m/-26 16 15 15 N 60 Tw, = Water temp 2 cm
1130 m/-19 1.9 0.8 N 63 below surface ~
1600 m/-17 19 18 18 2.4 1.2 NN 64 100 m downstream
from inlet
7 Feb 0815 m/-21 16 16 16 E 64 Tw, = Water temp 2 cm
1230 m/~19 1.9 0.8 E val below surface v
1545 m/-l9 18 19 18 2.5 1.1 WwW Th 200 m downstream
from inlet
10 Feb 0830 m/-29 18 17 16 NE nm. Tw, = Water temp 2 cm
1130 -19/-19 3.2 1.4 E 10 below surface v
1545 -19/-20 18 17 16 3.8 1.7 E 10 300 m downstream
from inlet
11 Feb 0830 -2h/-29 17 16 16 NE 2T
1130 -25/-26 24 1.2 SE he
1545 m/-26 17 16 16 NE 39

* Indicates missing data


APPENDIX A. DESIGN FOR AN AUTOMATIC THIN CHEMICAL FILM
APPLICATION SYSTEM

The application of a thin chemical film to the pond can be done by a
number of methods. An automatic system would consist of the following
devices: a slurry tank with mixing impeller capable of mixing 0.21 m? (55
gal) of water and chemical slurry. (In the case of EGME the chemical is
applied in its natural liquid form.) The tank is connected to a header
which extends across the upstream end of the pond. The header should be 49
m (150 ft) wide and have holes every Sqm (15 ft) (Fig Al). A pump capable
of delivering approximately 1.5X10-7 m°/s (1/4 gpm) to the header is
needed. The header should be supported on the pond by floats so that it
stays at the water level of the pond. This will keep it in contact with
the pond level. A common industrial timer should be used to activate the
system once every four days. Each time 0.076 m3 (20 gal) of slurry and/or
chemical should be pumped out into the pond.

Power
Plant

(W)Winehol Header—SS>c Slurry Bidg
(A)Anchora]

wal Do0000q

A

i

pooooooonna | (Pulleys

w I
Aa
WORDS

Dock q®*—Instrument
Bldg.

Cooling
Pond

fe]

Pulleys

ot
=Ev=EvE

rae
U
YY

Figure Al. Design sketch of chemical application system - plan view.

28


TABLE B-3.

METEOROLOGICAL DATA

FORT WAINWRIGHT
COOLING POND, DECEMBER 1975

RADIATION
NET INCOMING TEMP °F Temp °F
RAD AVG RAD AVG AVG SFC AVG +2m 24 HR AVG OF
Day 1000 1600 1100 1600 1100 1600 1100 1600 -1m SFC +2cm +2m +Om
L +70 +70 -18 -17 +70 +70 +40 -15 -19
2 14.7 19.6 13.2 13.6 +67 +66 -26 6-26 +67 +66 +30 ~25 -26
3 +64 +63 -33 0 -37 +64 +64 +30 -34 -34
4 +62 +60 -38 = -ho +62 +61 +36 -37 -36
5 16.6 10.4 +56 +56 430 -h2 +58 +57 +19 -41 -h2
6 453° $5302 -39- -40 #55. +53. «+20 -40 -hO
T +52 +50 430-43 454 +52 +29 -hQ -h2
8 +50 +50 -4200 =k +53 +51 +30 -42 -h1
9 +50 = +50 -39 —_-39 +52 +50 +32 -39 -hoO
10 450 451-360 -35 +53 451 +31 -36 -37
11 452 +54 -34 0-31 455 +54 +34 -32 -33
12 455 +55 2-32, 33. #56 +52 «+51 -28 -30
13 +56 (+56 -10 -7 +58 +56 +55 - 9 -10
14 +58 +59 -11 -15 +60 +58 +58 -11 -12
15 11.8 +59 +61 -6 +68 +63 +61 +hb8- 1-2
16 +65 = +66 41300 +14 +68 +65 +59 +17 +17
17 +68 +70 #29 0 +25 +71 +69 +5 +27 +27
18 +64 +64 +25 417 +65 +65 +38 419 417
19 11.4 10.6 24.2 26.7 +73 +74 +24 +27 +71 +69 «+40 #21 +21
20 +72 +73 41h 415 +74 +69 +h0 +12 +12
al +69 +70 +2 +2 +72 +70 +33 + 3+ 3
22 14.2 20.9 +68 +70 +21 © +20 +73 +69 +43 415 +14
23 +71 +70 +15 +11 +73 +71 «+40 +12 +11
2k +66 +61 +7 +9 467 465 43h 4545
25 +58 = +58 +16 9 +10 +62 +60 +35 +15 +14
26 +69 -5 +70 +69 +32 -1- 3
27 +60 +63 +h +3 +65 +61 +hO+ 7+6
28 +60 +57 -1 -1 +62 +60 +38 + 3+ 2
29 16.7 17.0 +55 +55 41-4 +58 456 +47 - 2 - 4
30 +5300 +54 -12 -4 +56 +54 457-5 -5
31 +55 +55 #1200411 +59 +51 +54 +11 +10

3T


ICE FOG FROM COOLING PONDS
EVAPORATION

The primary purpose of a cooling pond is to dissipate waste heat from
the power plant, and evaporation is one of the primary mechanisms by which
heat is transferred to the atmosphere. It accounts for a major portion (on
the order of 25%) of the total heat dissipated from the open water surface
during the winter months. Elimination of ice fog from power plant cooling
ponds could be accomplished by elimination of evaporation from these ponds.
Therefore, evaporation suppression and ice fog suppression become synonymous.

When heat loss is inhibited through evaporation suppression, it must
be made up by other means to avoid operating problems at the power plant.
This can be accomplished by a number of methods; therefore, a knowledge of
the magnitude of this heat loss is essential to the design engineer so that
he may incorporate adequate alternate heat transfer modes into the system.

Since evaporation is a function of many interacting variables, mathe-
matical predictions are difficult. This is particularly true in the
microclimate around the pond, since the size of the pond creates conditions
that differ from those of laboratory experiments which have been used to
predict evaporation rates.

Wind is also an important parameter in the processes of the climate
around the pond. Even though traditional meteorological measurements may
indicate an absence of wind, the pond actually produces its own air move—
ment, caused by the buoyancy of air which is warmed by contact with the
pond surface. To replace this buoyant rising air, colder air is drawn in
around the edges of the pond, producing a flow of air from the sides across
the warm water towards the center. The air flow then rises to produce a
plume and finally drifts away from the pond vicinity to gradually cool and
settle until it rejoins the layers of air near the ground. While the air
is warming, its ability to hold moisture increases, and evaporation into
this relatively dry air is rapid. As the air leaves the pond surface, it
begins to cool and its ability to hold moisture decreases, its vapor
condenses, and formation of ice fog particles begins. The process is
difficult to measure or estimate since the air movement is below the
threshold of most standard meteorological wind measurement instruments and
is composed of a large number of eddies and small convection cells whose
direction varies constantly and randomly, making measurement of either
windspeed or direction very difficult.

RELATIVE HUMIDITY AND COLD AIR

Relative humidity is a measure of the air's ability to hold moisture;

5


TECHNICAL REPORT DATA

(Please read Instructions on the reverse before completing)

T, REPORT NO. 2.
EPA-600/3-79-007

3. RECIPIENT'S ACCESSION NO.

4. TITLE AND SUBTITLE
Ice Fog Suppression Using Thin Chemical Films

IS. REPORT DATE
January 1979

6, PERFORMING ORGANIZATION CODE

7. AUTHOR(S)
Terry T. McFadden and Charles M. Collins

8. PERFORMING ORGANIZATION REPORT NO.

9. PERFORMING ORGANIZATION NAME AND ADORESS
U. S. Army Cold Regions Research and Engineering

70, PROGRAM ELEMENT NO,
1AA602

Laboratory, Alaskan Projects Office, Fort Wainwright, [11 CONTRACT/GRANT No.

Alaska 99703 EPA-IAG-D7-0794

12, SPONSORING AGENCY NAME AND ADDRESS 13, TYPE OF REPORT AND PERIOD COVERED
U. S. Environmental Protection Agency Final _11/75-3-77
Arctic Environmental Research Station 14. SPONSORING AGENCY CODE

College, Alaska 99701
EPA/600/02

15. SUPPLEMENTARY NOTES.

16, ABSTRACT

Ice fog suppression experiments on the Fort Wainwright Power Plant cooling pond
were conducted during the winters of 1974-76. Baseline information studies occupied

a sizeable portion of the available ice fog weather in 1974-75. Hexadecanol was added
to the pond and dramatically improved visibility by reducing fog generated from water
vapor released by the pond at -14°C. Although this temperature was not low enough to
create ice fog, the cold vapor fog created was equally as devastating to visibility in
the vicinity of the pond. During the winter of 1975-76, suppression tests were con-
tinued using films of hexadecanol, mixes of hexadecanol and octadecanol, and ethylene
glycol monobutyl ether (EGME). Suppression effectiveness at colder temperatures was
studied and limits to the techniques were probed. A reinforcing grid was constructed
that prevented breakup of the film by wind and water currents. Lifetime tests indicat
ed that EGME degrades much more slowly than either hexadecanol or the hexadecanol-octa4
decanol mix. All the films were found to be very effective fog reducers at warmer
temperatures but still allowed 20% to 40% of normal evaporation to occur. The vapor
thus produced was sufficient to create some ice fog at lower temperatures, but this
ice fog occurred less frequently and was more quickly dispersed than the thick fog
that was present before application of the films.

7. KEY WORDS AND DOCUMENT ANALYSIS

ja. DESCRIPTORS lb. IDENTIFIERS/OPEN ENDED TERMS |c. COSATI Ficld/Group
Alcohols Cooling ponds
Cooling towers

Eielson AFB, Alaska

Ethylene glycol mono-
butyl ether

Fairbanks, Alaska

Fort Wainwright, Alaska

Hexadecanol

Ice fog suppression

Electric power plants
Evaporation control*
Ice fog*

Injection wells
Monomolecular films*
Water cooling systems

13/B

M8. DISTRIBUTION STATEMENT 19. SECURITY CLASS (This Report} 21. NO. OF PAGES

RELEASE TO PUBLIC UNCLASSIFIED 51
20. SECURITY CLASS (This page) 22. PRICE
UNCLASSIFIED

EPA Form 2220-1 (9-73) .
45 S:GPO 697-485,


METEOROLOGICAL DATA

TABLE B-6.

FORT WAINWRIGHT
COOLING POND, MARCH 1976

RADIATION TEMPERATURE
NET INCOMING TEMP OF TEMP °F
RAD AVG RAD AVG AVG SFC AVG +2m 24 HR AVG OF

Day 1000 1600 1100 1600 1100 1600 1100 1600 ~-1m SFC +2cm +1m +2m
1

2 +30 +38 +16 +422 +37 +37 +38 +20 +20
3 +38 +50 +21 +30 +h1 +h2 +hh +23 +23
4 452 +52 +31 +30 +51 +51 +47 +28 +28
5 32.7 +50 +50 +23 +29 +50 +50 +38 +22 +22
6 36.7 30.4 +h9 +h9 +429 +37 +50 +h9 +ho +28 +30
T 39.8 32.3 +50 +51 +26 +34 +50 +50 +38 +27 +27
8 35.5 +50 +50 +25 +30 +51 +50 +37 +22 +22
9 +h7 +48 +1 +26 +50 +48 +32 +16 +16
10 +48 +48 +200 +25 +49 +49 +37 +17 +16
11 4h5 +4500 +100 #15 t+h7 +46 +32 + 9 413
12 +45 +h5 +160 +22 +h6 +45 +36 415 +15
13 +uh +45 +24 +20 +45 +h5 +38 +17 +17
14 tuo +41 413 +17 +hh +43 +40 +10 +11
15 32.0 +h +17 +h2 +h1 +39 + 7+7
16 35.4 +43 +41 411 +13 +43 +42 +42 +10 +10
1T 20.8 +41 +41 +6 +45 thi +h tho +545
18 +41 +h300 + Bh +42 +42 +40 +10 + 8
19 46.9 36.5 +42 +42 +22 +24 +hh +42 +43 +15 417
20 +h2 +42 +11 = +20 tho +h2 +43 +24 +14
21 52.1 41.7 +ho +45 +45 +18 +34 +39 +40 +14 +14
22 47.9 +40 +41 +27 +33 +ho +40 +41 +22 422
23 +410 +4200 -+2300:«+3K +43 +41 +38 +21 +21
2h +42 +42 +17) +23 +44 +41 +33 +19 +19
25 +41 44200-4160 +28 +43 +42 +32 +16 +16
26 +hQ +430 «+1602 +2 +43 +41 +31 +13 +13
2T +42 +420 «+19 +32 +hh +41 431 +17 +18
28 +40 +42 «4150 #2 +43 442 431 +15 +14
29 +42 +41 +28 + 74+ 7
30

31

43


REINFORCED FILM EXPERIMENTS

In order to test techniques for maintaining the integrity of chemical
films for ice fog suppression, experiments were conducted during the
winters of 1974-75 and 1975-76 at the Fort Wainwright power plant cooling
pond,

This cooling pond is located outside the southeast corner of the
Fairbanks city limits (Fig. 3). It is approximately 305 m (1050 ft) long X
150 m (500 ft) wide (Fig. 4). It is divided into unequal sections by a
dike extending down the middle, leaving the two sides connected at the
south end by a 15-m-wide channel. Hot water from the power plant is
introduced at the north end of the western section of the pond, circulated
counterclockwise around the dike and taken in again at the north end,of the
eastern sec}ion of the pond. The open water portion of the 45,740-m
(492,200-ft") surface produces a dense plume of ice fog that drifts with
the prevailing winds over parts of Fort Wainwright or across the Richardson
Highway where several automobile accidents have been attributed to reduced
visibility.

|
extn
K
Fairbonks
A
(IE
\ \ ae
S 5
Sorin 00 Oe eed]
¥ Road q
> aa
{ Boe
$
Fort Wind Rose
Wainwright ‘wPower Plant (Nov'78 Feb'76)
Cooling
Pond
Richardson Hwy. U
Oo O.5milé
° O.8km

Figure 3. Location of Fort Wainwright power plant cooling pond.

15


ee

TABLE B-1. (Con't)
Average Relative humidity
Ta,/Tay Tw, Two TW; Windspeed Wind 1/4 mile upwind
Date Time °¢ °c °c _°C (mph) (m/s direction (2)
12 Fed 0830 =23/-29 17 16 16 NE 39
1130 -22/-23 4.600 2.2 NE 10
1545 -23/-25 17 17 16 5.7 2.5 E 26
13 Feb 0830 -28/-30 16 15 15 E kg
1130 ~24/-25 7.1 3.2 E 53
1615 -26/-28 15 15 14 6.3 2.8 E 2h
14 Feb 0830 -28/-32 13 12 12 E au
1145 ~25/-28 3.4 1.5 NE 23
1545 -25/-22 14 1k 13 21.9 0.8 E 63
15 Feb 0830 ~-25/-27 15 NE 59
1145 -22/-25 3.3 1.5 sw 10
18 Feb 0830 -12/-12 18 17 16 s 80
1130 2 --12/-13 5.3 2.4 s 23
1600 -14/-24 18 17 #17 3.30 «21.5 WwW 72
19 Feb 0845 -19/-20 18 16 W 71
1145 -18/-20 6.1 2.7 Ww 72
1600 -19/-1T 16 15 15 3.4 1.5 SE 65
20 Feb 0830 -29/-31 17 17 16 E 33
1130 -25/-25 14.6 6.4 E 55
1530 -22/-23 17 17 17 4.5 2.0 E 50
21 Feb 0830 -8/-6 19 18 #47 NE 60
1130 2 -3/-3 6.7 3.0 E 43
1530 -1/-2 19 18 18 5.1 2.3 E 88
24 Feb 0830 -19/-20 18 18 18 E 23
1130 -13/-15 2.4 1.2 E 15
1530 -6/-10 20 19 19 l.4 0.6 E Th


FOREWORD

Effective regulatory and enforcement actions by the Environmental Pro-
tection Agency would be virtually impossible without sound scientific data on
pollutants and their impact on environmental stability and human health.
Responsibility for building this data base has been assigned to EPA's Office
of Research and Development and its 15 major field installations, one of
which is the Corvallis Environmental Research Laboratory (CERL).

The primary mission of the Corvallis Laboratory is research on the
effects of environmental pollutants on terrestrial, freshwater, and marine
ecosystems; the behavior, effects and control of pollutants in lake systems;
and the development of predictive models on the movement of pollutants in the
biosphere.

Corvallis' Environmental Research Laboratory's Arctic Environmental
Research Station conducts research on the effects of pollution on arctic
and subarctic freshwater, marine water and terrestrial systems and develops
and demonstrates pollution control technology for cold climate regions.

This report describes a two-year study of ice fog suppression from power

plant cooling ponds using inexpensive chemical films to reduce the evapora-
tion from the ponds.

James McCarty
Acting Director, CERL

iii


REFERENCES

Behlke, E., and J. McDougall (1973) Polyethylene sheeting as a water surface
cover in sub-zero temperatures. Proceedings of the 12th Alaskan
Science Conference. University of Alaska, Fairbanks.

Benson, C.S. (1965) Ice fog: Low temperature air pollution. Geophysical
Institute Report UAG R173, 43, (DDL no. 631553).

Benson, C.S. (1970) Ice fog. CRREL Research Report 121, AD .708544.

Chang, S., M. McClanahan, and P. Kabler (1962) Effect of bacterial decom-
position of hexadecanol and octadecanol in monolayer films on the
suppression of evaporation loss of water. In Retardation of evapora-
tion by monolayers, New York: Academic Press, p. 119-130.

Coutts, H.J. and R.K. Turner (in press) Research on control technology for
ice fog from mobile sources. Environmental Protective Agency, Envir-
onmental Research Laboratory, Carvallis, Oregon.

Dressler, R.G. (1969) Evaporation retardants based on blends of alcohol
containing odd and even numbers of carbon atoms and methods of use.
U.S. Patent Office No. 3,340,488.

Johnson, P.R. and C.W. Hartman (1969) Environmental atlas of Alaska. In-
stitute of Arctic Environmental Engineering, Institute of Water Re-
sources, University of Alaska, Fairbanks.

Kumai, M. (1964) A study of ice fog and ice fog nuclei at Fairbanks,
Alaska. Part 1. CRREL Research Report 150, AD 451667.

Kumai, M. (1966) Electron microscopic study of ice-fog and ice-crystal
nuclei in Alaska. Journal, Meteorological Society of Japan, June 1966
II(3), p. 185-194.

Marks, L.S. (1951) Mechanical engineers' handbook. New York: McGraw Hill.

McFadden, T.T. (1976) Suppression of ice fog from power plant cooling ponds.
CRREL Report 76-43.

Noe, E.R., and R.G. Dressler (1969) Performance of pure odd and even chain
fatty alcohols in water evaporation suppression. Industrial and
Engineering Chemistry Product Research and Development, vol 6,
no. 2, p. 132-137.

26


problems should be involved.

One factor that raises some problems beyond the capabilities of
present technology is the low groundwater level in the aquifer during the
winter months. Should the wells run dry or too low for adequate water
supply, the power plant could be put into a cooling crisis. However, an
emergency solution to this is to reopen the cooling pond. This would cause
ice fog, of course, but would save the power plant from a shutdown.

The cost of drilling a 45-cm (18-in.) diam. and 30-m (100-ft) deep
hole with a perforated casing plus the cost of well development come to
$20,360. Assuming three such wells would be necessary for adequate backup
for injection and two such wells would be necessary to provide adequate
water for cooling, the total cost for the well drilling would be $101,800.

Annual operating costs of the injection wells are difficult to assess
since they depend on well plugging, water quality, and pumping costs. If
an additional 50-hp pump is adequate to supplement present circulating
pumps and a pump and well lifetime of 10 years is used, the initial capital
cost would be approximately $10,000. Pumping costs at $.041/kWh* equal
$13,391/year. Increased labor required for more frequent cleaning of
condenser tubes will amount to 2 man-days per week or 832 man hours/year at
$15/hour, equaling $12,480. The yearly cost for the injection well system
at 8% for 10 years totals $42,532.

Despite the high cost, this is a technique that definitely warrants
further investigation. The problems, both technical and social, do not
appear to be insurmountable, and the predominant advantage of absolute
suppression of all ice fog emanating from the cooling waters of the power
plant is very attractive. The cost of evaluating the feasibility of the
injection well technique is, however, well above the funding level of this
study.

COOLING TOWERS

Dissipation of the waste heat from the condensers could be accomplished
through the use of dry cooling towers. Wet (evaporative) cooling towers
could not be used, however, since they would provide an enormous water
surface area which would produce immense amounts of ‘ice fog.

Dry cooling towers, liquid to air heat exchangers where the liquid is
not free to evaporate into the atmosphere, would accomplish the purpose of
dissipating the unneeded heat without using the evaporative process. This
technique has certain advantages over the injection well technique and has
some similarities. As with the use of injection wells, it provides 100%
suppression of the ice fog while dissipating the required waste heat.
However, it differs from the injection well technique in that it does not
rely on the continuous input of groundwater. The water used is treated and
will not cause excessive corrosion or plugging of either the condenser
tubes or the cooling tower.

*Blectric rate charged by the government to its agencies in Fairbanks
(K. Swanson, personal communication, 1977).

12


Figure 5. Rows of 8-ft-diam. hoops installed on the
cooling pond. Weather at this time was
not conducive to ice fog formation.

APPLICATION OF THE HEXADECANOL FILM

Sufficient baseline data had been collected by mid-February 1975 to
begin experimental application of the hexadecanol film. It was desirable
to apply the film on a calm, cold day of -30°C or colder when ice fog would
be present, but no such day occurred during the remainder of February and
into March. Therefore, a calm day at -14°C was finally selected even
though only vapor fog was present. Except for the relatively warm tem-
perature, atmospheric conditions were favorable for an experimental appli-
cation of hexadecanol on Tuesday, 4 March. Winds were calm, and the sky
was overcast.

Hexadecanol in a granular form was applied to the pond from a small
boat starting at 0820 hours. The boat traversed from the warm to the cool
side of the pond spreading approximately 9 kg (20 1b) of chemical to the
warm side and approximately 3.5 kg (18 1b) to the cool side. Finally,
hexadecanol was applied to the areas within the film reinforcing hoops.
Specific proportioning was not attempted, the only consideration being to
ensure that each section of the pond received alcohol well in excess of
that required for a monomolecular layer. The total time for application
was 20 minutes.

Photographic coverage was obtained from several vantage points to
record the appearance of the fog before, during, and after application.
Photos taken from a circling helicopter afforded the clearest perspective
of the changes in the fog. An overall reduction in the fog is clearly
apparent in the aerial photos (Figs. 6-8). Furthermore, Figures 9 and 10
show a remarkable local contrast in the fog. Large areas of the pond show

18


expensive initial capital investment is required, although an automated
dispensing system would facilitate alcohol application. The cost for an

automated dispensing system (described in Appendix A) would be as follows:

Pumps and tanks $ 1,000.00
Controls and timers 500.00
Piping and headers 200.00
Hoops 10,000.00
Winches, 54 at $220.00 each 14,580.00
Building and house dispensers 5,000.00
Miscellaneous hardware 1,500.00
Anchors, 54 at $100.00 each 5,400.00
Cable, 12,000 ft at $.0h/ft 480.00
Labor, 360 hours at $25.00/hr 000.00

Total $47,640.00

Chemical costs per year amount to less than $500 and routine main-
tenance should not require more than 1 man-hour per week for the 16 weeks
of ice fog weather, for a cost of $400. Total annual cost for 10-year life
at 8% interest is $7,998.00 per year, which would be substantially lower
than for any other technique, as can be seen in Table I.

TABLE I. Cost comparisons for ice fog suppression.

Probability
Method Capital cost Annual cost of success
Polythelene $52,550.00 $12,931.52 Very low
film cover
Polyethylene 228,515.00 39,980.00 Low
rafts
Injection wells 111,800.00 42,354.00 Moderate to High
Cooling towers 143,290.00 21,354.00 High |
Chemical films 47,640.00 7,998.00 High for partial
suppression

ay


Ohtake, T. (1969) Studies on ice fog. Geophysical Institute, University
of Alaska, Final Report. Prepared for National Center for Air Pollution
Control. Public Health Service, Dept. of Health, Education, and
Welfare, Washington, D.C.

Rimshaw, V.A. and Donchenko (1958) Winter heat losses from an open surface
of water (in Russian). Trudy Gosudarstvennogo Gedrologicheskogo
Institute, Gedrometeoizdat, Leningrad.

Roberts, T.D. and J.S. Murray (1968) Electrostatic precipitation of ice
fog. The Northern Engineer, vol. 1, p. 45.

Robinson, E. (1953) An investigation of the ice fog phenomena in the
Alaska area. Project No. 473, Stanford Research Institute, Menlo
Park, California.

Shell Oil Company (1974) Shell oil herder, Bulletin, Shell Oil Company.

Tedrow, J.E. (1969) Exhaust moisture reduction by prototype heat exchanger.
Internal Report, Alaska Field Station, U.S. Army Terrestrial Sciences
Center, Fairbanks, Alaska.

Weller, G.E. (1969) Ice fog studies in Alaska. Geophysical Institute,
University of Alaska, Report UAG R-207.

Yen, Y.C. and G. Landvatter (1970) Evaporation of water into a subzero air
stream. Water Resources Research, vol. 6, no. 2, p. 430-439.

eT


ponds. Polyethylene sheeting was proposed by Behlke and McDougal (1973).
In their experiments using a small evaporation pan, they found that eva-
poration, and thus ice fog, could be totally eliminated by use of the
plastic film to cover the pans. But extrapolating this concept to a body
of water as large as the cooling pond (over 40,000 m°) incorporates some
problems of large magnitude.

A 6-mil (0.015-cm) polyethylene film large enough to cover the cooling
pond area weighs in the neighborhood of 7700 kg (17,000 1b). The handling
of such a film is a major construction task requiring large equipment and a
carefully designed supporting structure. In order to dissipate heat from
the pond, a film must float in contact with water that is moving through
the cooling pond at approximately 0.113 m/min. This produces an average
drag on the film of slightly under 900 N (200 lbf), which is sufficient to
tear the film away from its moorings if they are not carefully designed. A
thicker 10-mil film would weigh on the order of 12,700 kg (28,000 1b) and
compound the handling problem still further.

Polyethylene film is very susceptible to degradation from the ultra-
violet. Clear film would be good for approximately one year and would have
to be replaced annually. Black film, which is slightly more stable, could
possibly last three years before replacement, assuming the film could be
installed so that it would not be damaged by its moorings.

If the film were to tear away from its moorings, the results could be
catastrophic. Should it enter the intake line to the power plant, it would
stop cooling water flow to the plant and result in the shutdown of the
plant within a matter of minutes. If this happened during an ice fog
period, the entire Fairbanks power grid would be deprived of one of its
prime producers at a time when power demand was very high. The ability of
the other producers to make up for this loss is subject to some question,
and at best would require considerable time. The clearing of the film from
the intake could require a good deal of effort since the intake portion of
the pond is covered with ice and the intake is submerged. Even the remote
possibility of this occurrence is sufficient grounds for a veto of this
technique by those responsible for operating the power plant.

Initial capital investment for the installation of a film to cover the
pond is shown below. The labor for installation and sealing together of
the individual 6-m (20-ft) wide sections together raises the cost con-
siderably.

The following cost estimate for covering the cooling pond with poly-
ethylene film is based on 1977 Fairbanks prices for materials and labor:

Capital cost for polyethylene film $10,300
Supporting structure 28,250
Labor for installation of support structure,

360 man-hours 9,000

Labor for installing the film, 200 man-hours 5,000

Total $52,550


INTRODUCTION

Ice fog has plagued man since the beginning of community development
in Alaska. It is a direct result of man's activities in the cold of the
Alaskan winter.

Ice fog results from excess water vapor in the air which condenses and
freezes, forming dense clouds of ice particles so small (8-35 um) that they
remain suspended in the atmosphere for long periods of time. Visibility
restriction is an obvious danger that results from the fog, and recently
the possibility of health hazards has also come to light. Many of the
nuclei of the ice particles have been found to be products of combustion
(Ohtake 1969), and it is feared that respiratory problems could result from
inhaling such particles. In addition, the concentration of pollution
products produced by adsorption on the ice particle surfaces has been the
subject of some concern (Benson 1970).

Through the years, the sources of water vapor have increased. Heating
of homes was the first source, introducing water vapor from combustion
products into air too cold to accommodate the moisture. With the intro-
duction of power plants the problem became more severe; products of com-
bustion as well as cooling water discharges were combined at a single
location to produce a concentrated source of ice fog. The increasing
numbers of automobiles in Alaska compounded the problem still further.
Today, the fog becomes a severe visibility pollutant in many areas at
temperatures as high as -30°C (-22°F).

Many studies on the nature of ice fog have been conducted and much
valuable information concerning its sources (Robinson 1953 and Benson
1965), its composition (Ohtake 1969) and its distribution (Benson 1970) has
been obtained. Studies of ice fog nuclei (Kumai 1964 and 1966) have given
additional insight into the origin and behavior of ice fog.

The extremely cold air which is conducive to the formation of ice fog
is usually a result of temperature inversions which trap very stable air
layers in valleys, such as the one where Fairbanks is located. The hills
surrounding Fairbanks are often 10°C to 20°C warmer than the valley floor.
Iee fog, once formed, accumulates progressively as long as the temperature
inversion keeps the air trapped over the city. The thickness of the
inversion layer increases with time, as does the density of the fog.

With the beginning of construction on the Alyeska pipeline project, a
great influx of new cars into the Fairbanks area created some of the worst
ice fog in memory during the winter of 1974-75. This was mitigated somewhat
by the relatively mild winter of 1975-76. However, the increased population


LABORATORY TESTS OF SUPPRESSION EFFECTIVENESS

A test was devised to measure the ability of various films to suppress
the evaporation component of heat lost from a water surface. The basis of
the test is the assumption that evaporative heat loss is a good quantitative
measure of evaporation. The procedure is to place pans of water covered
with various films in a coldroom at varying temperatures. The pans are
insulated on all sides, leaving only the surface of the water exposed to
the cold of the room. Heat loss, as the pan cools, is then limited to
losses from the water surface: radiation, convection, and évaporation.
The convective and radiative losses should be equal. The only difference
in the cooling rate of the pans will be that of the evaporative cooling
losses due to the difference in suppression effects of various chemicals on
the surface. In this manner, the evaporation suppression by various chemi-
cals can be compared to the control pan (water without chemicals). Figure
13 shows the results of some of these tests. Using this technique, it can
be seen that hexadecanol is more effective than EGME, and that mixtures of
hexadecanol and octadecanol are somewhat better than the hexadecanol alone.

T T T T T T T T T
40 Air Temp. = -15°C 7
$ 30h 4
‘é Hexadecanol
€ plus
F 20F Octadecanol 4
3 Hexadecanol
lok EGME 4
HO"
° 1 1 i 1 1 aL 1
° 0 =620—C—«Ss—“<iKsti(iKsC‘<CiRKCTCsC(‘i‘ SC
Time (min)

Figure 13. Effect of chemical films on heat transfer rate
from water surfaces.

In order to combine the qualities of long life and higher spread
pressure of EGME with the better evaporation inhibiting qualities of hexa-
decanol, a mixture of EGME and hexadecanol was tested. However, the
suppression qualities tended to be very close to that of EGME alone. This
may be caused by the higher spread pressure of the EGME, separating the
molecules of hexadecanol and resulting in EGME as the only cover over most
of the water surface. The immiscibility of hexadecanol in EGME may also be
a factor. It has not yet been determined whether hexadecanol will establish
a film in the presence of EGME. Further studies on this particular subject

2h


Figure 10. Alcohol film layers accumulating at the leading edge
of the hoops, just prior to applying hexadecanol to
the hoop area.

From the ground the film was observed to be swept slowly downstream by
the surface current. After approximately an hour, the hexadecanol was
found concentrated in layers against the band of hoops midway down the warm
side, and against a surface dam separating the two sections of the pond.
Fog was absent approximately 25 m (80 ft) upstream of the surface dam where
the hexadecanol film tapered from thick scum at the dam's edge to a mono-
molecular layer film upstream (Fig. 11 and 12). Alcohol was also found
clinging to some edges of the pond where it was calmer.

Atmospheric conditions were constant throughout the hour of photo-
graphic coverage (0820 to 0920). Winds remained calm; the sun remained
shaded by heavy clouds, and the air temperature rose only 1°C. The hexa-
decanol, therefore, appeared to be the only variable responsible for the
fog suppression.

HEXADECANOL, OCTADECANOL MIXES

There is some evidence that longer chain alcohols are more effective
than hexadecanol in suppressing evaporation (Dressler 1969). However, the
longer chain alcohols come at a much higher price. Some evidence exists to
indicate that mixes of the different alcohols provide even greater sup-
pression ability (Noe and Dressler 1969). In an effort to test this
theory, a supply of octadecanol (C, gH,0H) was obtained and mixed with the

21


CONTENTS

Disclaimer. . 2. 1 ee ee ee ee ee eee

Foreword. 2 6 2 6 ee ee ee ee ee ee
Abstract. © 6 6 ee eee ee ee eee
Figures . 6 6 6 ee ee ee ee ee ee ee
Tables 6 2 6 we we ee ee ee ee we
Acknowledgments . 2. 1 6 2 ee ee ee ee ee
Introduction. ©. 6 6 6 ee ee ee ee ee
Conclusions . . 6 6 1 ee ee ee ee eee
Ice Fog From Cooling Ponds. ......-++e.
Evaporation. ... . rs
Relative Humidity and co1a Air... ..
Ice Fog Suppression. - .- . +e eee eee
Air movement . 6 6 6 6 ee eee ee ewe
Plastic films. . 2... 6 1 ee ee eee
Rafts. 2 6 6 ee ee ee ee ee ee ee
Injection wells. . 2... 6 ee eee eee
Cooling towers... ee eee eee eee
Chemical films... .. +. +. ee eee
Reinforced Film Experiments . . ee ee ee
Meteorological Data Collection ry
Floating Reinforcement Grid. .......
Application of the Hexadecanol Film... .
Hexadecanol-Octadecanol Mixtures .....
Ethylene Glycol Monobutyl Ether. .....
Laboratory Tests of Suppression Effectiveness .
References... 6 1 ee ee ee ee ee ee

Appendix A. Design for Automatic Chemical Film

Appendix B. Meteorological Data. .......

Dispensing System

iii

iv

vi

vi

vii


ABSTRACT

Ice fog suppression experiments on the Fort Wainwright Power Plant
cooling pond were conducted during the winters of 1974-76. Baseline in-
formation studies occupied a sizeable portion of the available ice for
weather in 1974-75. Hexadecanol was added to the pond and dramatically
improved visibility by reducing fog generated from water vapor released by
the pond at -14°C. Although this temperature was not low enough to create
ice fog, the cold vapor fog created was equally as devastating to visi-
bility in the vicinity of the pond. During the winter of 1975-76, sup-
pression tests were continued using films of hexadecanol, mixes of
hexadecanol and octadecanol, and ethylene glycol monobutyl ether (EGME).
Suppression effectiveness at colder temperatures was studied and limits to
the techniques were probed. A reinforcing grid was constructed that pre-
vented breakup of the film by wind and water currents. Lifetime tests
indicated that EGME degrades much more slowly than either hexadecanol or
the hexadecanol-octadecanol mix. All the films were found to be very
effective fog reducers at warmer temperatures but still allowed 20% to
40% of normal evaporation to occur. The vapor thus produced was sufficient
to create some ice fog at lower temperatures, but this ice fog occurred less
frequently and was more quickly dispersed than the thick fog that was
present before application of the films.

This report was submitted in fulfillment of Interagency Agreement EPA-
IAG-D7-0794 by APO-USACRREL under the sponsorship of the U.S. Environmental
Protection Agency. This report covers a period from November 1975 to March
1977, and work was completed as of March 1977.

iv


In addition, there would be an annual operating cost for replacement of
film of $5,100 assuming a three-year lifetime for the black polyethylene.
Over a 10-year period at 8% interest, this would give an annual total cost
for ice fog suppression of $12,931.52/yr.

Once the film is installed covering the entire pond, ice fog sup-
pression would be complete. However, the first snowfall -- and Fairbanks
averages about 125 cm (50 in.) of snow per year (Johnson and Hartman
1969) -- would cover the film and soon melt, resulting in water on top of

the film which would then produce ice fog and negate the function of the
filn.

RAFTS
A variation of the film suppression technique which has been proposed
to avoid the problem of water on top of the film (J. McDougall and R.

Carlson, personal communication, 1974) is to construct small rafts (Fig.
2) that have the polyethylene stretched across the top. The film then has

“Sis ZO

Styrofoam

Plywood Structural Frame
Bok Jig thick x 4" wide . Polyethylene Sheeting
(0.35¢m) x (10.16 cm) Weight 4

: = —t

Styrofoam 2"x4" tps
(5.08em) x (10.16 em)
sft
f (244m) |

Figure 2. Cross-section of polyethylene covered raft.

a hole cut in the center and is weighted down so that any water falling on
the surface will drain to the center and run through the hole into the
pond. The costs of this type of installation are gonsiderably higher, than
for the single film. For coverage of the 46,469 m° of pond by 5.95-m
rafts, 7,812 units are required. Construction costs should run as follows:

Styrofoam 24 in. x 9.75 m at $0.43/m $ 4.00
Plywood structural frame 10.2 cm wide x 0.95 cm thick 7.27

Bolts - 24 x $0.15 each 2 2 3.60
Polyethylene film - 6.4 m° at $0.21/m' 1.38
Glue and nails 0.2
Total for materials $ 16.75
Labor (mass production -- 1/2 hr/unit) at $25/hr $ 12.50
Total 725

10


ACKNOWLEDGMENTS

The authors wish to express their appreciation to the Fort Wainwright
facility engineers for their help and cooperation in this project, and to
the Fort Wainwright power plant personnel for snow-plowing access routes
and cooperating during installation difficulties.

The helpful suggestions, manuscript review, and liason work of Mr.
Merritt Mitchell and Mr. H.J. Coutts of AERS were particularly appreciated.
This work was done under a grant from the U.S. Environmental Protection

Agency, Arctic Environmental Research Station.

vii


|
|
|
l
H Structure
1
{| circutation | L- dike
1 Pattern
Relative |
Humidity

fH Instrument
Sensor "
3 H

1 oaph—Foere

244m

yom (800 ft)

28 |

i}

1

|

|

\

i}

it |
i! i
{! boc5000 |

Boococae000cc0g

{| pococasece j
1

ll C0000 |
{1} Floating OOO |
iT] Hoop |
lI Grid |
i \
iH |
U |

(500 ft)
R.H. Sensor
450m (1476.1 ft)

{

Figure 4. Layout of Fort Wainwright power plant cooling pond.

METEOROLOGICAL DATA COLLECTION

Meteorological data were collected at the pond site by the Fort
Wainwright Detachment, U.S. Army Meteorological Support Activity. Data
taken included wind direction, windspeed, ambient air temperature, water
temperature, relative humidity, and radiation exchange. Wind, air tem-
perature and radiation data were taken at the dock midway along the center
dike. Relative humidity was measured approximately 400 m (1350 ft) to the
west of the pond and 1200 m (4000 ft) to the south. Meteorological data
are tabulated in Appendix B.

FLOATING REINFORCEMENT GRID

Previous studies have shown that the alcohol film is easily displaced
by the wind (Ohtake 1969, McFadden 1976). In order to effectively suppress
evaporation from a water surface with an alcohol film, it is necessary to
protect the integrity of the film. A floating grid offers a means of
reinforcing the film so that it will not be broken up, blown aside by the
wind, or carried away by the current.

16


United States Environmental Research
Environmental Protection Laboratory
Agency Corvallis OR 97330

Research and Development

SEPA Ice Fog

Suppression Using
Thin Chemical
Films

> Hs



TABLE B-h.

METEOROLOGICAL DATA

FORT WAINWRIGHT
COOLING POND, JANUARY 1976

39

RADIATION TEMPERATURE
NET INCOMING TEMP OF TEMP OF
RAD AVG RAD AVG AVG SFC AVG +2m 2h HR AVG OF

Day 1000 1600 1100 1600 1100 1600 1100 1600 -1m SFC +2cm +1m +2m
L +59 +62 +4 +3 +66 +62 455+ 7+ 7
2 -19.3 14.5 +63 +63 +1 +2 +65 +62 +42 + 3+ 3
3 +62 +62 -6 -5 +65 +62 +28 - 4-5
4 +61 +59 -15 ~10 +63 +60 +34 -14 -1h
5 -14.3 -17.5 19.5 16.8 +58 +57 -14 -2 461 +58 #438 -7- 8
6 -12.0 15.7 +57 +55 -8 -6 +61 +57 «+41 - 2 - 3
1 456 +57 - 8 -14 +58 +57 «+42 -12 -13
8 +48 +48  -30 -30 +49 +49 +48 -29 -30
9 ~9.7- 8.6 15.5 15.3 +48 +40 +31 -33 +4h +43 +43 -32 -33
10 +39 +hO -35  -36 +h2 +39 +h2 -35 -35
il +43 +43 --33 -30 +hh +41 +h5 -32 -32
12 tuk 443° -29 -25 +47 +44 447 -27 -27
13 - 7.2 - 7.8 18.4 19.2 +50 +48 -25 -22 +50 +46 +51 -14 -24
1h -10.0 20.8 18.6 +h7 +51 -21 ~-20 +53 +49 +53 -21 -22
15 +50 +50 -22 -18 +54 +49 +54 -20 -21
16 -11.0 17.3 +50 -20 -18 +55 +51 +55 -19 -19
1T +52 +49 -16 = -1h +52 +50 +51 -14 -13
18 - 4.9 - 7.2 +h6 +45 o -2 447 +45 4h7 + 24 1
19 25.3 2h.7 +46 +h3 +7 +8 +h7 +hhy +47 4+ 74+ 6
20 +h3 +41 -|-1 -121 +h6 +43 +46 O- 1
21 - 5.2 - 7.2 +h2 +40 +1 0 +hh +43 445 20 0
22 23.0 17.9 +hl +ho -14 -13 +h2 +ho +42 -12 -12
23 +38 «4437 «-2h = -20 +39 +36 +39 -22 -22
2h 435 +34 -2h 9 +13 +35 +34 +35 -17 -17
25 +32 +32 +8 = +10 +33 +33 +34 + 6 + 8
26 8.2 21.0 +39 +35 +7 +2 437 +36 437+ b+ ih
27 9.0 19.8 +32 +31 -10 -7 +34 +32 +34 - 6 - 8
28 +33 +33 4-10 -10 +35 +33 +36 -11 -13
29 +36 +36 «+19 +27 +39 +35 +39 +17 +18
30 28.5 22.5 +38 +41 +24 +22 +40 +38 +h2 +22 +22
31 +37 «+38 «+4 +8 +h0 +38 +34 444+ 6


CONCLUSIONS

The dramatic improvement in visibility from reduction of fog after
application of hexadecanol suggests that this technique may be very useful
for economic reduction of cooling pond contributions to the overall ice fog
blanket of the Fairbanks area.

Chemical films are clearly the most economically attractive method.
Although they only partially suppress fog, the cost of 100% suppression is
267% higher for the cooling tower approach and 532% higher for the in-
jection well technique. No other techniques discussed would yield 100%
suppression.

The performance of a grid to reinforce the film was very satisfactory
and appeared to function much as predicted. It is felt that the problem of
maintaining the film integrity has been satisfactorily solved for light
winds and water currents. Stronger winds (that might overcome the effect
of the reinforcing hoops) would probably dissipate the ice fog anyway.

The rapid bacterial degradation of the hexadecanol and octadecanol
films presents a problem which must be approached using one of several
techniques. Treating the film to destroy the bacteria without harm to
other ecological systems may suffice. Another alternative would be to use
films which are not so readily biodegradable, for example, ethylene glycol
monobutyl ether. This film has been shown to be harmless to marine life
(Shell Oil Co. 1974) and it is also biodegradable, but at a much lower rate
than hexadecanol. Other advantages include a much higher film spread
pressure and a liquid state at normal temperatures. It is immiscible in
water and practically invisible. Suppression effectiveness of EGME is
lower than that of hexadecanol, but its longer life and higher spread
pressure are compensating factors. One application per season is suf-
ficient, and a viable film cover still appears to be intact at the end of
the winter.

Further research is needed to identify other chemicals which will
suppress evaporation and perhaps even surpass the effectiveness of those
investigated in this report. It is apparent that much of the visibility
problem can be alleviated with films at a very reasonable cost. But it
must be realized that chemical films that provide only partial suppression
(up to 80%) will still allow some ice fog to leave the pond. Since visi-
bility in the immediate vicinity of the source is an inverse exponential
function of ice fog density, it quickly drops to near zero with only a
small amount of ice fog present. Although little advantage of the sup-
pression activity can be seen in the immediate vicinity of the source, the
dispersion of fog as it moves away from the source allows visibility to


density in the Fairbanks area will remain, and every effort must be made to

reduce sources of ice fog and its harmful effects on health, highway
safety, and aircraft operations. This report describes an investigation of

techniques for ice fog suppression at one of the major sources of ice fog
in the Fairbanks area, the Fort Wainwright power plant cooling pond.


TABLE B-2. FORT WAINWRIGHT
COOLING POND, NOVEMBER 1975

METEOROLOGICAL DATA

RADIATION TEMPERATURE
NET INCOMING TEMP °F TEMP °F °
RAD AVG RAD AVG AVG SFC AVG +2m 2h HR AVG °F

Day 1000 1600 1100 1600 1100 1600 1100 1600 -lm SFC +2em +1m +2m
1 -3.17 -11.16 29.27 13.10 42 uy 8 6 4304 4 2 3
2 -5.5 -12.33 24.81 18.12 51 3 46 50 9 2 1
3 -1.5 - 7.16 31.5 20.63 50 hg 8 10 51 49 9 lo 9
h -6.66 -11.3 22.86 13.7 486 48 5 7 hg LB 5 5 6
5 -5.0 - 6.7 25.9 22.3 h6 46 -1 T WT 46 3 302
6 -6.7 -10.2 25.0 17.8 4h 45 6 6 u5 Ub 9 6 5
7 -2.2 - 2.3 26.8 25.4 bh kh 19 37 uh Yb 22 2h 23
8 -0.2 -6.7 28.4 20.1 46 43 30 28 47 45 31032 31
9 +#1.8 - 2.0 30.9 26.8 4b an 2h 31 47 be 2h 230 2h
10 -0.4 6.3 29.0 21.7 49 50 Wh 31 4g 4h 3h 360-85
11 -1.2 - 4.8 29.3 23.4 49 43 27 =o 50 43 25 27 27
12 -0.4 - 4.8 31.2 24.0 51 M ho he 51 17 36 38 39
13 -4.3 - 4.3 28.7 27.0 ho 4g kg 43 53 47 be obs 5
1h -h.2 - 6.7 24.5 20.9 53 50 30 30 52 54 29 30 30
15 -4.8 5.3 2.0 22.9 45 UT 37 41 52 h6 35 37 38
16 -1.3 - 3.3 27.9 25.0 46 47 30 31 52 46 30 32 31
17 0.5 - 2.7 30.7 26.2 48 ké 31 33 5u 7 32 «032 «32
18 -1.2 - 6.3 33.5 22.0 50 9 eT 25 54u 48 26 26 2
19 -7.7 -11.5 22.3 16.7 43 yd 11 8 52 41 10 11 10
20 -9.8 - 8.5 18.7 14.2 ho ho 6 9 yo 4o 7 8 7
21 -2.0 -6.7 27.6 22.0 43 45 23 32 48 43 2b 25 2h
22 -8.3 - 8.2 22.9 18.1 41 41 14 18 48 bo 15 17 16
23 -6.7 8.3 22.0 19.5 37 38 07 06 46 38 08 09 08
2h -2.2 - 4.8 26.8 22.6 41 yy ak 14 46 41 130 1h 13
25 -5.0 - 9.8 22.3 13.9 ki AL 08 05 46 bi O07 09 08
26 -1.8 - 2.3 25.0 25.0 4h2 43 14 20 yh 42 12 13 «13
27 -6.7 - 2.3 22.0 2h.0 45 Ay 3h 23 46 Uh 26 28 27
28 -0.2 3.5 27.9 26.5 h6 46 33 43 48 45 32 «3h 33
29 -2.8 - 3.7 25.7 25.0 M M M M MoM M OM M
30 -2.3 2.8 29.3 27.3 M M M 46 52 ko be Ub he

35


hexadecanol (C, 6H OH). The mixture was 20% octadecanol and 80% hexadecanol.
Neither superior 3 rformance nor superior lifetime could be confirmed with
the use of this mix when compared to hexadecanol alone. However, due to
equipment failure, it was impossible to make any quantitative measurements
using either the transmissometer or high volume sampler. Clearly more work
needs to be done in this area to confirm or dispute any improved suppression
performance of alcohol mixes under ice fog conditions.

ETHYLENE GLYCOL MONOBUTYL ETHER

A chemical marketed by Shell Oil Company with the trade name, "Oil
Herder," was investigated for its fog suppression capability. It is
primarily used on water for concentrating oil spills into a small area
where they can be easily handled. The chemical is ethylene glycol mono-
butyl ether (EGME), a clear liquid that has a high spread pressure and low
vapor pressure. According to the Shell Oil Company research brochure, it
is nontoxic both to humans and fish and is biodegradable.

The chemical was applied to a cooling pond at the Eielson AFB power
plant and the suppression effectiveness monitored during the winter.
Several rows of floating hoops were placed on the pond, but their presence
did not appear to be as important to film integrity as when the long chain
alcohols were used. It is difficult to assess the precise suppression
effectiveness of EGME due to the lack of funds or time for comprehensive
tests; however, laboratory tests indicate that it suppresses approximately
60% of the evaporation from an open water surface as compared to hexa-
decanol's suppression effectiveness of as high as 85%. Its increased spread
pressure helps it to resist tears in the film and gives it a longer life-
time, a distinct advantage over hexadecanol. During the months while the
film was on the Eielson cooling pond, no adverse affects to the pond, the
power plant, or any of its operations were observed. The suppression
effectiveness appeared to be good. No quantitative measurements were
possible; however, it was apparent that the pond was not a major ice fog
contributor while EGME was on the pond, whereas the stacks from the power
plant still contributed significantly. In many instances visibility across
the pond was unrestricted while ice fog covered the rest of the base.
Although its cost is several times as high as that of hexadecanol, one
application of EGME appeared to be adequate for the entire ice fog season,
making it economically competitive.

23


TABLE B-4. (CONTINUED)

WINDS HY GROTHERMOGRAPH

DRASTIC WINDS

WINDS (24 HR AVG KNOTS) 14HR 1 HR 24 HOUR AVG
ISLAND RAFT BEFORE AFTER WEEDS DOCK

Day W/D W/s W/D W/S W/D W/S W/D W/S Rh ‘Temp Rh Temp
1 154 lo 61.5
2 48 2.9 20 1.9 8 -2
3 93 -T v1.3 86 - 2
y 90 451.0
5 90 481.1 TT
6 110 2.3 134 «41.8 719
T 115 1.8 340 1.6
8 95 31 «1.2
9 121 «1.4 v1.2
10 130 0 220 «1.0
11 102 v1.0
12 127 302 «1.0
13 88 1.8 232 1.0
14 50 -T ah
15 62 v1.0
16 172 #1.0 221 2.0
17 v “5 352 75
18 135 -3 225 a
19 202 “9 225 6 86 +6
20 215 «4 221 8 bho a1
21 210 1.3 225 1.5 8h 0
22 167 -9 241 1.7 81-13
23 100 0 42 1.0 100 = -23
2h 78 #0 352 1.0 100-27
25 45163 45 2.1 100 +5
26 45 6.5 WS gS 2.0 45 5.0 64 0
27 89 4.7 50 2.0 mH - 4
28 v1.5 v1.2 80 -10
29 90 2.7 uS5 ou 65 +15
30 135 3.8 177 2.2 225 2.0 225 2.0 76 +20
31 90 2.2 445 1.1 92 +1

ko


Figure 11. Pond 2h hours after application. Note that the film
is still actively suppressing the fog in the area of
the hoops.

Figure 12. Pond 48 hours after application. Film still is
intact in the area of the hoops.

22


Number

10.

il.

12.

13.

1h.

FIGURES

Low temperature psychrometric chart. ........
Cross section of polyethylene covered raft ......
Location of Fort Wainwright power plant cooling pond .
Layout of Fort Wainwright power plant cooling pona we
Rows of 8-ft diam. hoops installed on the cooling pond
Pond before application - 0820 hours ........
Overall fog reduction at 0910 hours. ........4
Large areas with little or no fog at 0920 hours. . .

Large clear area upstream of hoops and along west edge
of pond prior to applying hexodecanol. .......

Alcohol film layers accumulating at the leading edge of
the hoops, just prior to seeding the Roop area with
hexadeconal. ......- - soe ee rs

Pond 24 hours after seeding. Note that the film is still

actively suppressing the fog in the area of the hoops.

Pond 48 hours after seeding. Film is still intact in
the area of the hoops. . . 2. ee 1 ee ee eee eee

Effect of chemical films on heat transfer rate from
water surfaces 2. 6 6 6 ee eee ee ee ee ee

Excess water vapor (fog) produces vs. temperature. .

TABLES

Cost comparisons for ice fog suppression. ......-

vi

10
15
16
18
19
19

20

20

21

22

2h
25

14


Two main problems exist with this method. The first is the large
initial cost, and the second is the possibility of a freeze-up when the
system is being operated at outdoor air temperatures as cold as -65°C. An
equally critical problem is that the system must be kept leak-free.
Experience with this type of closed circulating system in arctic conditions
does not present an encouraging record. However, this is more of an
operating problem than a technological one, and no insurmountable techno-
logy gaps appear to exist.

The Rainey Corporation in Tulsa, Oklahoma, manufactures closed cooling
towers which would meet the requirements for this project. A basic unit
could cool the water for the Ft. Wainwright power plant to a temperature of

9°C and remove 7,648 kW (26.100.000 BTU/h) from the recirculated cooline
fluid. The cost of this system is as follows:

Dry type cooling tower $ 76,190
Shipping for 43,775 kg (96,300 1b) 9,600
Site preparation including concrete pad and

ground work 10,500*

Piping to route the cooling water from the
condensers to the cooling tower and return,

including valves 22,000*
Pumps capable of circulating the water at
138 kPa (20 psi) pressure 11,000
Installation and electrical hookup of pumps 14, 000*
Total $143, 290*

The total cost of this unit, amortized over a 10-year lifetime at 8%
interest, yields a figure of $21,354 per year.

CHEMICAL FILMS

Ice fog suppression using long-chain fatty alcohols was investigated
by Ohtake (Weller 1969) who found that he could not maintain the integrity
of the alcohol film. McFadden (1976) confirmed this observation with
experiments in 1973 at the Eielson AFB power plant cooling pond. In these
experiments, it was found that even the very light breezes resulting from
the cooling pond's natural convecticn plume and currents from the normal
circulation of water were sufficient to disrupt the integrity of the film.
However, McFadden (1976) also found that hexadecanol suppressed evaporation
(and, therefore, ice fog) by as mch as 80% in standard Colorado evapora-
tion pans. On the basis of these studies and considerations, it was
proposed to develop and test methods of reinforcing the films. This report
discusses the results of such tests (see next section).

Suppression with alcohol films is an attractive option because costs
for chemical application are very low. Chemicals cost less than $100.00
per application, and labor costs are less than $75.00 per application. No

*Items designated with the asterisk are estimates based on 1977 Fairbanks
prices. All other items are quoted prices.

13


@. Raised Position

Ly Hoops Floating on Surface <=

Pond

b. Lowered Position

Figure A3. Design sketch - chemical application system —
hoop raising concept.

be 2x 4
| (16 hoops ot 15 Ibs each) |

ae) eee a <6
Tritt

k—§

Figure Al. Catenary arc calculation parameters.

Let:
w = weight/ft
y = ft
ex = 270 ft (x = 135 ft)
= tension (1bf)
Z = auxiliary variable

for: 1/l-in. cable (breaking strength > 4000 lbf)
w = 0.1 lb/ft for cable + 0.92 for hoops = 1.02
wx = 138.5 1b

30


Table 1. Cable tension (1bf) vs. deflection for one span (Marks p. 2-57).

Weight

y y/x z wx/T Cable Cable+hoops s/x s

2 0.0148 0.0296 0.0296 456 4679 1.00015 135.0
4 0.0296 0.0592 0.0593 228 2335 1.00059 135.1
6 0.0444 0.0888 0.0889 152 1558 1.00132 135.2
8 0.0593 0.1185 0.1167 116 1187 1.00272 135.4
10 0.0741 0.1480 0.1464 92 946 1.00365 135.5
15 0.1111 0.2213 0.2160 62 641 1.00818 136.1
20 0.1481 0.2940 0.2817 48 492 1.01447 137.0

If a catenary is such that it touches the water surface at y = 20 ft and
then is further relaxed until the line lies on the water,the total relaxed
length is

Ly = (28 + 135 - 20) (2) = 286 ft.

208 28 f1(8.5m)
(6.im)] 1559
at

208 270 ft

(82.2m) 1

Figure A5. Calculations for arc touching water surface at y=20.

Since the stretched length when the center of the cable arc is 10 ft above
the surface of the water is:

Ls (135.5 x 2) = 271 ft.

Then AL = 286 - 271 = 15 ft per arc.

For a motor pulley to raise two spans of hoops would require a takeup
capacity of (15) x (2) = 30 ft.

Hoops would have to be free to slide along the cable during the takeup
process to avoid entangling them in the pulleys (Fig. A4).

Electric winch units capable of exerting a tension of 8416 N (1892 lbf)
are required to lift the center of each catenary 3.1 m (10 ft) above the
surface; 1/4 in. steel cable should give an adequate safety factor.

Although a lift of 3.1 m (10 ft) will not raise the centermost loop
completely from the water, it will be sufficient to allow the hexadecanol
or EGME to flow into the hoop area and be captured when the hoops are
lowered. One winch could then handle two spans.

31


little if any fog, while immediately adjacent are thick walls of fog
marking the edge of the film.

Figure 6. Pond before application--0820 hours.

Figure 7. Overall fog reduction at 0910 hours.

vy


DISCLAIMER

This report has been reviewed by the Corvallis Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for publica-
tion. Approval does not signify that the contents necessarily reflect the
views and policies of the U.S. Environmental Protection Agency, nor does
mention of trade names or commercial products constitute endorsement or
recommendation for use.

ii


TABLE B-3. (CONTINUED)

WINDS HY GROTHERMOGRAPH

DRASTIC WINDS

WINDS (24 HR AVG KNOTS) 1 HR 1 HR 24 HOUR AVG
SLAND RAFT BEFORE AFTER WEEDS DOCK

Day W/D w/s w/p w/s w/D W/S W/D W/S Rh Temp Rh Temp
l 34 3.4

zZ 15 1.5

3 105 2.1 120 1.2

4 106 2.0 132 1.4

5 86 2.6 94 .8

6 162 1.8 198 1.9

T 122 1.7 135.2

8 98 1.0 72 .3

9 104 13 86 29
10 TT +3 50 «8

11 125 90 «5S

12 99 124

13 ehh 259

14 92 125

15 200 90 +2
16 91 +7
iv

16 17h 3.1
19 102 4.6 104 2.7 101 4.0 99 4.0

20 gu 3.8 139 1.3
21 199 1.8

22 107 1.9 320 1.2 88

23 150 -5 310 1.0

2u 110 2.3 295 1.4

25 191 263 1.1

26 168 302 1.2

27 137 1.4
28 241.9
29 157 2.1 350 1.5 90 -2
30 207 1.0 315 2.0

31 186 232

38


TABLE B-2. (CONTINUED)

WINDS

HYGROTHERMOGRAPH

DRASTIC WINDS

WINDS (24 HR AVG KNOTS) 1 HR 1 HR 24 HOUR AVG
ISLAND RAFT BEFORE AFTER WEEDS DOCK
Day W/D W/S W/D wW/S W/D wW/S W/D W/S Rh Temp Rh Temp
1 ) 0 000 ©8600 99 -- & 55 -3
2 0 0 000 00 99 -7 re)
3 05 010 090 = oO1 98 T 55 6
4 87 01 190 02 100 2 5T ()
5 140 ol 180 02 100 -1 56 -1
6 175 01 000 0 m m S56 -1
T 087 o4 117 03 nm 18 4g 19
8 180 05 «6258 =O 19 au 50 2T
9 172 02 070 o1 99 175k 22
10 110 oh 080 02 84 29 46 32
a1 100 02 ©6080 02 16 20 43 2h
12 135 03 050 OL 19 33.039 35
13 98 oh 070 02 72 ho 39 4O
14 132 01 070 o1 88 22 52 23
15 091 02 O70 O21 TT 30 37 32
16 000 00 =—.000 00 8h 22 46 2k
17 109 01 000 00 97 25 5k 27
18 210 01 080 01 96 17 54 21
19 000 00 000 8 00 92 - 2 50 ()
20 000 00 000 = 01 91 2 50 ()
21 130 02 090 «1 89 19 43 22
22 000 00 = 000 00 98 4 * T
23 000 00 ©6000 00 96 - 2 * 2
2h 000 00 =©—000 00 98 6 * 11
25 000 00 ©000 00 oh = 5 * 0
26 226 02 212 01 ou 5 * 10
2T 167 02 170 01 96 20 * 26
28 195 or 192 01 93 26 * 33
29 117 03 «114 02 91 29 * 25
30 93 03 113 02 TH 37 «986 23

* Invalid Data

36


100% relative humidity is the maximum amount of moisture that the air can
hold at any temperature. Figure 1 is a low temperature psychrometric
chart -- a graphical display of the relationship between air temperature
and the amount of water that can be held by the air at various relative
humidities. It shows that air with 100% humidity at -25°C (-13°F) can hold
0.5 mg of water vapor per gram of dry air. If this air then cools to
-35°C, it can only hold 0.2 mg of water vapor per gram of dry air. There-
fore, warm moisture-laden air (at 100% relative humidity) leaving the pond
and cooling must lose some of its moisture. This is done by condensation
and the formation of ice fog particles or vapor fog droplets.

Low Temperature Psychrometric Chart
(Metric Units)

Sn a a i i i oS
Ory Bulb Temperature (°C)

Humidity Ratio (Groms of Water Vapox per Grom of
Dry Air)

Figure 1. Low temperature psychrometric chart.

Several investigators have measured evaporation during cold weather.
Yen and Landvatter (1970) conducted laboratory experiments of evaporation
from water into very cold air. Ohtake (1969) reported on experiments with
small 35-mm film cans during ice fog conditions in Fairbanks. Behlke and
McDougal (1973) described evaporation from a pan on the top of the University
of Alaska Engineering Building during the winter of 1973, and McFadden
(1976) reported on evaporation from two standard Colorado pans floating in
the Eielson Air Force Base power plant cooling pond during the winter of

1973.

In 1802 John Dalton proposed a formula for evaporation which has
become known as Dalton's law. This formula states that evaporation is
equal to some function of windspeed multiplied by the difference in vapor
pressure between the water surface and the air into which the water has
evaporated. It is stated as

E= f(u) (e, - e,,)

al
where
E = evaporation in the unit time and area
ea = water vapor pressure in air 2 m above the surface


ICE FOG SUPPRESSION

Elimination of ice fog has been approached along several avenues of
research. Roberts and Murray (1968) demonstrated that electric fields
could attract at least some types of ice fog particles. Tedrow (1969)
designed and tested an exhaust gas dehydrator for a 2-1/2-ton truck that
virtually eliminated water vapor emissions, and in 1972 McKay (personal
communication 1972) designed and installed a furnace dehydrator that also
greatly reduced emission of water vapor. Coutts (1977) developed and
tested several automobile exhaust dehydrators; some showed very good
results during the winters of 1974-75 and 1975-76.

Suppression of the formation of ice fog from power plant cooling ponds
was first attempted using an ice cover (McFadden 1976). The cold surface
of the ice evaporated several times (as much as 10 times) more slowly than
exposed areas of the warmer water that it covered. This technique proved
very effective on the Eielson Air Force Base power plant cooling pond, and
ice fog produced by the pond was reduced to a negligible level. However,
the complexities of forming and maintaining the ice sheet over the warm
(20% to 15°C) water made the technique difficult to implement (McFadden
1976).

AIR MOVEMENT

Serious consideration has been given to the concept of blowing ice fog
away from selected areas such as airports. For example, suggestion was
made to install large fans along the edge of the runway and thus draw air
from an area free of ice fog, blowing the fog away from the runways to keep
them clear for aircraft operation. However, it was shown that energy
requirements for this would be excessive and much denser ice fog would form
around the power plant where the energy was generated (McFadden 1976).

Another variation of this proposal was the use of helicopters to hover
at the top of the inversion layer. The downwash from helicopters would
draw warm ice-fog-free air into the rotors and propel it downward to clear
the runway. Since helicopter operations are very expensive, the costs for
this technique are very high. Although some limited success was achieved
in the immediate vicinity of the runway using this technique, complete
results have not yet been published. One of the problems encountered was
that the exhaust from the large turbine engines of the helicopters used was
incorporated into the downwash, and as this air cooled, it became an
additional source of ice fog in the general area.

PLASTIC FILMS
Plastic covers have been suggested for eliminating evaporation from

5 :


EPA-600/3-79-007
January 1979

ICE FOG SUPPRESSION USING

THIN CHEMICAL FILMS

by

Terry T. McFadden
and
Charles M. Collins

U.S. Army Cold Regions Research and
Engineering Laboratory
Alaskan Projects Office

Fort Wainwright, Alaska 97703

Interagency Agreement
EPA-IAG-D7-0794

Project Officer

Merrit Mitchell
Arctic Environmental Research Station
Corvallis Environmental Research Laboratory
Corvallis, Oregon 97330

J

CORVALLIS ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CORVALLIS, OREGON 97330


AMixing Motor
B.Mixing Tank (00 gal.)
C.Dispensing Pump

Figure A2. Layout of automatic chemical film dispensing system.

Each chain of floating hoops across the width of the pond should be
connected to a 1/h-in.-diam. steel cable (breaking strength of at least 17
KN (4000 1bf). The cable will extend from an anchor across the pond around
a pulley and back across the pond to a hoist capable of lifting 1,130 kg
(2500 1b) (Figs. Al and A2). When the hoist is activated, it will draw the
cable to a tension of approximately 11.1 kN (2500 lbf) which will lift the
cable and the attached hoops above the pond (Fig. A3). Floats attached to
the cable will keep it floating at the surface during the relaxed periods
to assure that it it does not sink any of the hoops. The hoops will be
attached to the cable by a sliding mechanism so that they may slide along
the cable as it is drawn up (Fig. A4). This will raise the hoops off the
water surface and allow the film to pass by. After the film front has
passed and spread over the area below the hoops, the hoops will be lowered,
entrapping the film within their confines and establishing a cover over the
entire pond.

Timing of the raising and lowering of the hoop chains will have to be
done during installation of the application system. The timing will be set
to raise the hoops so that the film will be allowed to spread and to lower
them before the film has completely passed. Once set, this time should not
change. Calculations for the design of the raising and lowering device are
given below.

29


Two methods were studied to establish a reinforcing grid on the
surface of the pond: black 1-1/4-in. diameter polyethylene pipe was formed
into large hoops which were floated on the pond, and in another section of
the pond floating polypropylene rope was stretched from bank to bank. The
floating rope initially appeared to be an easy and inexpensive solution to
the problem, as it floated high on the water and divided the surface into
small discrete units. After several days, however, the rope "waterlogged."
Water infiltrated between the fibers of the strands, and as a result, the
rope floated so low in the water that it only occasionally broke the
surface. The slightest breeze would drive ripples and alcohol film over
the top, negating its effectiveness. The polyethylene hoops, on the other
hand, proved to be very effective and stable, remaining afloat with suf-
ficient freeboard even after several months on the pond.

Although more convenient, smaller hoops enclose smaller water surface
areas than large loops, and require more pipe per square meter of surface
reinforced. The question therefore arises as to the optimum size hoop.
Since the larger hoop diameter lowers the cost of both material and in-
stallation, maximum size was desired. However, the largest size that will
still adequately support the film had to be determined. Hoops with dia-
meters of 2.4, 4.6, 9.1 and 15.2 m (8, 15, 30 and 50 ft) were fabricated
and placed on the pond. Hoops of 2.4-m (8-ft) diameter were found to be
very easy to fabricate and transport; however, they required far more
tubing than was available to cover the area desired for the tests. Hoops
with diameters of 9 m (30 ft) and larger, on the other hand, were found to
have poor shape stability while floating on the pond and would not give
adequate support to the filn.

Difficulties caused by the cold of late November in Alaska made it
necessary to fabricate the hoops indoors and then transport them to the
pond for installation. The 2.4-m (8-ft) diameter hoops were found to be
the largest practical size that was transportable during the cold without
specialized hauling equipment. During warm weather, when the plastic pipe
was more flexible, larger diameters could be transported because the hoops
could be deformed into ellipses without cracking or taking a permanent set.
The 4.6-m (15-ft) diameter hoops were then preferable due to economic
considerations.

Once the hoops were fabricated and transported to the pond, they were
fastened together in long chains, stretched across the surface, and secured
on each side. It was not necessary to connect adjacent chains and it was
possible to leave up to 3-m (10-ft) spaces between adjacent rows of hoops.
Figure 5 shows the rows of hoops installed on the pond.

Alcohol was spread on the water surface inside the different size
hoops, and it was found that after a period of several hours the film was
established and would maintain itself in the 4.6-m (15-ft) diam. hoops.
Applying alcohol during windy periods required a longer time for the
establishment phase.

17


RESEARCH REPORTING SERIES

Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields
The nine series are

Environmental Health Effects Research

Environmental Protection Technology

Ecological Research

Environmental! Monitoring

Socioeconomic Environmental Studies

Scientific and Technical Assessment Reports (STAR)
Interagency Energy-Environment Research and Development
“Special” Reports

9. Miscellaneous Reports

ONONSWNH =

This report has been assigned to the ECOLOGICAL RESEARCH series. This series
describes research on the effects of pollution on humans, plant and animal spe-
cies, and materials. Problems are assessed for their long- and short-term influ-
ences. Investigations include formation, transport, and pathway studies to deter-
mine the fate of pollutants and their effects. This work provides the technical basis
for setting standards to minimize undesirable changes in living organisms in the
aquatic, terrestrial. and atmospheric environments

This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.


METEOROLOGICAL DATA

TABLE B-5.

FORT WAINWRIGHT
COOLING POND, FEBRUARY 1976

RADIATION TEMPERATURE
NET INCOMING TEMP °F TEMP °F

RAD AVG RAD AVG AVG SFC AVG +2m 2k HR AVG OF
Day 1000 1600 1100 1600 1100 1600 1100 1600 -1m SFC +2cm +1m +2m
1 +37 0 +37 -4 -4 -ho +37 +36 - 5 - 6
2 +437 «+35 -13 -6 +37 +35 +35 -12 -12
3 +37 9 +35 4130-17 +38 +33 +36 +11 +11
4 +33 «+38 +27 +30 +41 +37 +38 +26 +26
5 - 7.8 27.7 +48 = +h8 +330 «+32 +h9 +47 +38 +33 +33
6 +50 +h9 42h 412 = +h7 +48 436 +17 +16
T +39 «= +38 -23 +25 +39 +39 +20 -23 -25
8 +32 +34 +21 -39 -39
9 +39 +37 +26 -38 -38
10 +37 «(+36 -31 = -28 +38 +36 +26 -36 -36
4 +35 +36 -38 = -31 +37 +38 +25 -38 -38
12 +35 +hO -36 20 +39 +38 +33 -33 -33
13 +37 = +ho -34 -22 +ho +38 +36 -30 -30
1h +37 +39 -29 = -27 +39 +38 +36 -32 -32
15 +40 +370 35-20 $39: +38) +36 -28 -28
16 23.8 +38 -21 +39 +38 +36 -28 -28
17 -14.2 20.1
18 -13.6 17.2
19 -14.8 20.6
20 13.6
21-7 -13.7 25.6 22.7
22-30 -14.1 28.4 22.6
23 - 5.2 23.5
24
25
26
27
28
29

4a


and more tests are clearly needed.

Figure 14 shows the effects,of varying degrees of water vapor sup-
pression. For example, 3.47 g/m“ min. of water vapor would be produced
from an open water surface at -20°C (point A). However, air entering the
pond area at 50% relative pumidity and leaving saturated woyld be capable
of absorbing only 0.95 g/m“ min. (point B) leaving 2.52 g/m" min, excess
vapor to form fog. If 80% suppression is achieved, only 0.6 g/m min would
be produced (point C). Therefore, no excess vapor would be available to
produce ice fog. If only 60% suppgession is achieved, then 1.3 g/m min
is produced (point D) and 0.35 g/m@-min of this is excess and will produce
fog (D-B). However, compared to the 2.52 g/m min of fog arising in the
case of no suppression, it is apparent that much less of the local area
will be affected for considerably less time.

Water vapor that con be absorbed by air
‘at noted relative humidity

Vopor entering air without suppression

7.0 (Aloska winter equation) 7
ooo Vopor entering oir at noted suppression efficiencies
60F Air Mass Flow Rote = 2300 g/m? min
Woter Surface Temperature = 10°C 25%

= 50

€
a

240

3

s

7 30

&

5

Ed

S50 -30 -20 10 °
Air Temperature (°C)

Figure 14. Excess water vapor (fog) produced vs. temperature.

Figure 14 also shows that if 80% suppression is achieved, fog will not
form until -23°C (-9°F), whereas without suppression fog will form at -10°C
(14°F). U.S. Weather Bureau records show that Fairbanks experiences an
average of 145 days during which the mean temperature falls below -10°C.
However, there are only 80 days of -29°C (-20°F) or colder. Therefore, the
suppression effort results in 65 fog-free days or 44.8% fewer days of fog.

25


HE

TABLE B-l. (Con't)

Average
Ta,/ Tay TTM Tw, Tw Windspeed
Date Time °C °c 2c _°C (mph) (m/s)

25 Feb 0830 +1.2/-4.2 20 20 20
1130 +3.3/+0.3 5.3 2.4
1530 +43.1/+0.2 20 20 20 1.1 0.5

26 Feb 0830 +1.1/-2.8 20 19 19
1130 +1.3/-1.9 1.8 0.8
1545 4+5.0/+2.1 21 20 20 2.7 1.2

27 Feb 0830 -2.8/-2.1 20 20 20
1130 +0.1/+0.3 3.1 1.4
1530 +3.9/+3.8 21 22 20 24 ll

28 Feb 0830 -13.9/-14.2 19 19 19

1130 -3.9/

1530 (7) 19 #19 19

3 Mar 0830 -13.2/-9.517 16 15
1130 -6.8 3.5 1.6
1515 () 18 #18 #418 4.30 1.9

4 Mar 0830 -14.0/-13.018 16 14
1130 -8.4 2.1 0.9

1515 -5.0 18 #18 #417

5 Mar 0835 -5.2 18 #18 417
1230 -2.1 6.3 2.8
1530 +0.7 19 19 #19 10.3 4.6

6 Mar 0830 -12.1 15 15 15
1125 -7.1 2.7 1.2
1535 -6. 16 16 #15 21 0.9

Relative humidity

Wind 1/4 mile upwind
direction (2)
E 93
83
E 82
E 82
E 76
E 65
s 88
SE 89
E 86
SE 10
NE 15
E
E
E 25
E
E
E
E
NE
NE
Ss
W


REI yaaa

Figure 8. Large areas with little or no fog at 0920 hours.

Figure 9. Large clear area upstream of hoops and along
west edge of pond prior to applying hexadecanol
to the hoops.

20


improve within a few hundred meters, whereas without the suppression effort
a much larger area is affected.

Eliminating all of the fog produced by the pond will be extremely
expensive and require one of the other techniques mentioned - or perhaps a
method yet unknown. Therefore, the economic cost of ice fog should be
determined to compare the cost of suppression with the cost of living with
ice fog. Although the fog is present only during a small portion of the
year, its cost can be high due to lost revenue from flights that cannot
land, repair of vehicles involved in accidents caused by fog, and the
possible loss of human life from accidents or health-oriented problems.
These economic factors clearly need to be investigated and considered.


TABLE B-5. (CONTINUED)

WINDS HYGROTHERMOGRAPH

DRASTIC WINDS

WINDS (24 HR AVG KNOTS) 14HR LHR 2h HOUR AVG
ISLAND RAFT BEFORE AFTER WEEDS DOCK

Day W/D W/S W/D wW/s wW/D wW/S W/D W/S Rh ‘Temp Rh Temp
1 116 -T 153 1.2

2 92 4 119°—«1..9 Bho + 1
3 113 “9 165 3.2 87 +23
y 118 «42.1 138 2.8 82 +36
5 148 02.7 «1230 «O21 179 +38
6 5.0 207 3.5 SW 4.0 SW 6.0 83 «+21
T 2.5 208 1.5 7] -15
8 1.7 17 ll 11

9 1.3 191 1.3 -32 Th -3h
10 9 70 1.0 -32 «Th -39
11 1.2 -32 (Th

12 1.0 117 -26 Th

13 1.4 137 2h Th

14 1.5 143 -23 Th

15 1.2 189 -21 «76

16 113. «1.2 «49208 «1.5 -18 7 -6
17 ikl 1.3 191 1.6 Ty -18 80 -8
18 122 1.1 1862 1.3 72 -25 76 -19
19 5h 1.9 5 2.8 7-11 69-11
20 150 1.5 161 1.3 TTM -25 15 ~-28
21 84 1.7 6 2.3 69 = -19 65-34
22 28 1.8 342 2.8 68 -12 59 - 5
23 150 1.5 81 1.5 66 = -20 69 -=20
2h 131 461.3 78 1.3 To -19 73 «-1T
25 161 1.0 93 «1.3 Tl = -16 79  -16
26 107 1.6 87 «2.6 65 -8 65 ~13
27 176 1.1 337 1.8 64 - 3 T2

28 154 8 2 8 68 -7T TT -5
290-172“ 8B 68 -3 19 +3

42


TABLE B-6. (CONTINUED)
WINDS HYGROTHERMOGRAPH
DRASTIC WINDS
WINDS (24 HR AVG KNOTS) 1 HR 1 HR 24 HOUR AVG
ISLAND RAFT BEFORE AFTER WEEDS DOCK
Day W/D w/S W/D w/s w/D W/S W/D W/S Rh ‘Temp Rh Temp
1 5 -3 88 .6 62 +.3 Th -2
2 45 -3 90 .8 57 +11 Jl +15
3 90 -2 47 1.2 87 «+26 85 +18
4 292 1.9 200 3.6 o 4 45 3 92 +28 gl +21
5 46 1.2 42 2.5 80 +23 75 +16
6 45 2.0 45 3.4 60 +32 53 +29
T 82 1.2 45 1.9 28h 4 180 4 89 «+27 86 +18
8 83 oh 72 «.T 91 +19 89 +12
9 82 any v.43 86 +13 84
10 2.8 221 1.3 4 6 Ji +17 72 +18
1 2.3 219 .8 82 +7 78 -6
12 1.7 12 1.0 90 +14 8h
13 3.9 210 2.3 91 +15 89 +11
14 3.3 195 2.2 79 +7 82 +9
15 1.0 21 .3 73 +2 #72 -2
16 2.6 225 1.5 TH +4 73 +6
17 45 3.7 68 fe) 59
18 45 1.4 81 +5 80
19 215 1.6 47 1.5 73 +13 72 +22
20 ««:178 = 1.0 Tw 79 +6 #19 +9
21 he 1.30 45 1.2 64 +11 70 +17
22 45 14 4l 3.9 45 +21 60 «+21
23 22T 218 1.4 65 +20 68 +17
2h 198 163.3 90 +16 88 +15
25 210 220 1.5 89 +16 89 +13
26 251 192 82 +8 80 +8
T 2he 199 1.7 65 +17 65 +18
28 22h 1820 66 «+12 72 +10
29 225 215 19 +5 176 43
30
31

Wh


e, saturation vapor pressure at temperature of water surface

f(u)

a function of the windspeed.

The form of the wind function is usually expressed as f(u) = (A + Bu) where
A and B are empirically derived constants and u the average windspeed 2 m
above the surface. Many variations of this formula have been proposed.
However, only Behlke and McDougal (1973), Rimshaw and Donchenko (1958), and
McFadden (1976) have proposed formulas based on data taken during winter
conditions in the Arctic. However, Rimshaw and Donchenko describe data
taken throughout Russia at many locations so southerly that they cannot be
considered arctic, and it is unclear whether the data from these sites were
incorporated into their equation. During a regression analysis to derive
an equation of the Dalton form from their data, Behlke and McDougal (1973)
found that the wind term dropped to zero. As mentioned earlier, wind, as
measured by meteorological instruments, is usually not detectable during
periods of ice fog but convective air flow is nonetheless present over
cooling ponds. The evaporation pan used in Behlke and McDougal's experi-
ments was placed on top of a building, away from the microclimate of a
cooling pond, and thus would not be affected by the induced air movement
caused by the convective heating in the vicinity of a pond. This is a
somewhat different situation than is encountered on a cooling pond itself.
A pond creates its own microclimate with very low but observable air
movements, even though windspeed at the local meteorological station or
weather bureau is recorded as zero.

In correlating data taken at the Eielson AFB power plant cooling pond,
the wind term was found to be present although small (McFadden 1976). This
equation states that

Q, = (13.1 + 0.132 u) (e, - e,) (W/m?)
where
a = evaporative heat loss
u = windspeed
= saturation water vapor pressure and water surface temperature
ee = saturation water vapor pressure at the air temperature 2m

above the surface.

A problem arises in the use of this formula. Since wind data available to
the designer are normally from weather bureau records, these data do not
reflect the convective instability over the pond. A modification of this
formula was made which replaces the wind term with a temperature term that
reflects the driving force for convective instability. It was derived from
data taken with Colorado evaporation pans on the power plant cooling pond
at Eielson AFB. This formula states that

= 2
Q, = [4.84 + 0.21 (f,-T,) I(e,-e,) (W/m*)
where T, and T, are the water and air temperatures, respectively. For lack

of a better name, this equation has been entitled the Alaskan Winter
Evaporation Equation.