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Date: | Sat, 3 Dec 2022 18:58:36 -0700 |
Content-Type: | multipart/mixed |
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>
> >>I remember only a couple of instances of some mold on lids and top
> frames. If I remember correctly it happened in colonies with a lot of
> space, stores and relatively low populations.
>
Two very good observations. 1) Moisture conservation - Bees seem to prefer
60-75%RH (@18C) 10-15g/m3 (moisture content) in cluster or in the "hot"
hive. Remember that air at 100%RH 0C only contains 4.85g/m3, so even in
warmish very humid winters, bees are required to up regulate moisture via
metabolic processes to maintain their setpoint. I believe bees under
certain conditions purposefully generate moist heat for the purpose of
humidifying which also results in internal condensation both of which
increases the in hive RH during very dry cold periods -30C Air @100% RH
0.46g/m3 . We do know that bees have mastered evaporative cooling which can
also be used to humidify air at cooler temperatures, ok in a hot hive but
not practical when bees are tightly clustered.
2) Mold when colonies where the bee # to volume is small - the attached
image shows this process in action. The red line is my calculated dew point
for the in cluster air. The colony on the left was very large and filled
most of the single broods area at temps above -10C. Notice how the dew
point coincides with the probable location of the cluster mantle ~10C
to14C, depending on the literature. The colony in the center was a smaller
colony in a single with much more "space". Notice how the dew point is well
away from the cluster location. These are frame top temperatures so you can
imagine the process of warm air rising and moving away from the cluster and
then starting to cool and dropping. The 4 corners also had RH & T sensors
at or near +95%RH indicating high saturation of the air near the sidewalls.
The right hive was my empty control to understand how much work the bees
need to do to regulate their environment (T and RH%). This is an hourly
snapshot in time.
Remember I have recorded many in hive heating events during really cold
times where entire in colony environment is heated to Ts of 20-28C above
bees and 15C below bees (measured above slatted rack) at outside Ts of less
than -30C.
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