Winter venting-top cover-cold climate

[derekm]

hey read this

OBSERVATIONS ON THE TEMPERATURE REGULATION
AND FOOD CONSUMPTION OF HONEYBEES
(APIS MELLIFERA)
BY J. B. FREE AND YVETTE SPENCER-BOOTH
Bee Research Department, Rothamsted Experimental Station

[rdy-b]

hey read this

OBSERVATIONS ON THE TEMPERATURE REGULATION
AND FOOD CONSUMPTION OF HONEYBEES
(APIS MELLIFERA)
BY J. B. FREE AND YVETTE SPENCER-BOOTH
Bee Research Department, Rothamsted Experimental Station

http://jeb.biologists.org/content/35/4/930.full.pdf

1958-- :) i will read it --RDY-B

[rdy-b]

 and im suposed to learn what from this magnitude of wasted time they spent --RDY-B

[JackM]

Finski:  You really should try to be more polite to others, your posts leave me with little respect for you because of your attitude.

All:

FACT: Heat always moves to cold. Cold does not move to hot.

That being said, solar gain from the sun would still move .... even through insulation albeit slowed... into the hive.  The ball heat of the hive will always be trying to exit until the exterior temperature is greater than that of the interior.  That exit can be in any direction, usually the direction of the greatest temperature differential.

Therefore the hive can get 'heat' from the sun on a dark surface.

I would not use tarpaper and foam  Both are perfect impermeable barriers, they will hold moisture from the bees respiration process inside the hive, and since it is warm in the hive, the air will hold more moisture.  As this warm moist air rises with normal convection and moves up to the top of the hive, there comes a point where the dew point is reached and condensation will form.  By insulating the sides or top enough to allow the inside of the hive to not reach the dewpoint, there will be no condensation, the moisture will exit with the natural ventilation of the hive.  How much ventilation I still am yet to learn.  Those are some darn hard cold facts folks about the way insulation and venting works.  Been that way forever.

Yes if you use foam provide a less than 1/8" airspace between the foam and the hive side.  This will effectively double the R-value of the foam.

Remember the ultimate goal is to prevent heat loss from the ball so they use less resources to survive the winter.

I know I am barely a beginner, but insulation was my business for many years, I know this topic regardless if it involves bees or not.  Sadly I hope the original poster is still reading and has not gone away because of the petty bickering.
Jack

[T Beek]

 X:X X:X

[derekm]

and im suposed to learn what from this magnitude of wasted time they spent --RDY-B

Then try this  - its from the paper:Endothermic heat production in honeybee winter clusters Anton Stabentheiner and others 2002.

"Southwick (1983, 1988) and Southwick and Heldmaier (1987) showed that the oxygen consumption of winter clusters increases as the ambient temperature decreases. The increase is moderate between approximately +10°C and –5°C and is steep below approximately –5°C to –10°C. In swarm clusters, the steep increase has already started at +10°C (Heinrich, 1981). Oxygen consumption also increases with decreasing cluster size (Southwick, 1985). Therefore, the frequency and intensity of endothermic heat production have to be assumed to increase with decreasing ambient temperature and cluster size. On the other hand, we suggest that at higher ambient temperatures large (swarm) clusters that have come to rest (e.g. at night) may be able to largely reduce endothermy (Heinrich, 1981)."

This means the colder it gets the more food they eat per bee, until you kill them... Then they eat no more.

[rdy-b]

 yes oxygen consumption goes up and carbon dioxide is produced--and bees* regulate metabolism*
with a condition of* hypoxia*--RDY-B

  Hypoxia-Controlled Winter Metabolism in Honeybees (Apis mellifera)

Experiments during three winters have revealed a metabolism controlling function of bee-induced hypoxia in the winter cluster. Permanent low oxygen levels around 15% were found in its core. This hypoxia was actively controlled, probably via indirect mechanisms. Varying ambient oxygen levels demonstrated a causal relationship between lowered oxygen and reduced metabolic rate (MR). Under deeper ambient hypoxia the bees switched to ultra low MR (ULMR), optional-occasional at 15% oxygen, obligatory at 7.5% oxygen. This dormancy status resembled deep diapause in insects. It stayed reversible after at least several days, and was terminated under normal oxygen at 15°C. Reduced MR via core-hypoxia is essential in water conserving thermoregulation of the wintering cluster. It allows bees to reconcile warm wintering in alert state—for defence of stores—with energy saving and longevity. Two further hypotheses discussed are that winter MR of bees might be related to insect diapause, and that in-body hypoxia might be functional in insect diapause.