Glacier Transportable Sampler - Isco
Glacier Transportable Sampler - Isco
Glacier Transportable Sampler - Isco
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<strong>Glacier</strong> <strong>Transportable</strong> <strong>Sampler</strong><br />
Appendix D Battery Selection Guide<br />
<strong>Glacier</strong> is programmed for continuous sampling, V c would be the<br />
programmed bottle volume, provided that bottle-full detection is<br />
being used. Use Figure D-1 to find A c by determining the<br />
amp-hours for the average ambient temperature at your sampling<br />
site.<br />
Once the sample liquid has been cooled, more energy is required<br />
to keep it cool. The second group in the equation may be used to<br />
calculate the amp-hours required each day to keep the sample at<br />
3° C. The number of days, D m , is the days from the first collected<br />
sample to when the <strong>Glacier</strong> is no longer expected to keep the<br />
sample cool. Use Figure D-2 to find A m .<br />
The following scenario illustrates how to use the equation. Consider<br />
a <strong>Glacier</strong> that is inhibited while waiting for an external<br />
device to indicate that a measured condition, such as a rain<br />
event, has occurred. The average ambient temperature is 30° C<br />
(86° F). When the external device clears the inhibit, the <strong>Glacier</strong><br />
will collect sample volumes of 250 ml, once an hour, for 24 hours.<br />
After running the program, it will take another day to retrieve<br />
the <strong>Glacier</strong> and bring the composite sample to the lab.<br />
From this example, we know that V c is 6 liters, D m is two days<br />
(one to collect the samples, another to retrieve it), and the<br />
ambient temperature is 30° C. At this ambient temperature,<br />
Figure D-1 tells us A c is 25, and Figure D-2 tells us A m is 29. The<br />
equation would be:<br />
( )( )<br />
V c x A c + D m x A m = Expected power consumption, Amp-hours<br />
6<br />
6 x 25<br />
+ 2 x 29 = 83 Amp-hours<br />
(<br />
6<br />
)( )<br />
Using the equation we find operating the sampler under these<br />
conditions would need a fully-charged battery with a capacity of<br />
at least 83 amp-hours.<br />
As previously mentioned, standby current is negligible. In the<br />
example above, the <strong>Glacier</strong> could be waiting several days for the<br />
rain event. Because the refrigeration system is not activated<br />
until the first sample is taken, the number of days the <strong>Glacier</strong> is<br />
inhibited is generally of no concern.<br />
Figure D-1 assumes that the liquid temperature at the sampling<br />
point is at room temperature (68 to 77° F or 20 to 25° C). Increase<br />
or decrease the expected battery capacity accordingly if the<br />
actual liquid temperature falls outside of this temperature range.<br />
Other factors, such as high suction head heights (over 3 m or 10<br />
feet) or the amount of direct sunlight will also affect the rated<br />
current demand on the battery.<br />
D-2