Weak thermocline = Wet hive ?

[bailey]

Aren't we all glad that bees don't read the same books that we do?
Them poor ole dumb insects have been living in hives of various dimensions and shapes for how long now?
And obviously surviving by doing what they know to do with their own thermodynamic needs by instinct?  

My hives have various amounts of ventilation that is set by the bees themselves. Some of my old inner cover type hives have their holes sealed with profilis in winter.  Some not.  
My migratory covers aren't air tight either.  

Glad they know how much air to let in to regulate themselves without me having to go through the headache
Of reinventing the wheel.

And finski is right about the wood absorbing the extra moisture. Otherwise we would be using thermoplastic hives with textured wood finish inside.

Thought of having swarm traps made of fiberglass but then thought of the condensation raining down on my fresh caught bees.  
Scrapped the idea!
Bailey

[BlueBee]

A sphere is just not applicable as a valid solution

I don’t know who determines a “valid solution” or not, but my jumbo hives have survived quite well in boxes that are very close to a square.  Brother Adams boxes were about square and Dadant was also fond of spherical shapes because he thought that was the most natural bee shape.   

I’m also seeing more condensation in my heat bubble designs as the aspect ratio increases.

My hives are not instrumented, so it’s hard to draw conclusions at this point, but what are you suggesting is the best shape?     

[BlueBee]

And finski is right about the wood absorbing the extra moisture. Otherwise we would be using thermoplastic hives with textured wood finish inside.

   I don't recall Finski claiming wood could absorb all the winter water vapor the bees generate?  He uses a top hole to vent.  

As for thermoplastic hives with textured wood finish inside, that is exactly how mine are built    However the wood isn't there to absorb condensation, the wood is there to keep the bees (and moths) from eating through the foam.  When I use a top vent, those hives have no condensation in them.

Solving the condensation problem is very simple.  Just add a top hole.  The problem/complication is when people also want to maximize the entrapment of the heat generated by the bee cluster.

[bailey]

I wrote extra moisture.  Not all moisture. 
Bailey

[derekm]

A sphere is just not applicable as a valid solution

I don’t know who determines a “valid solution” or not, but my jumbo hives have survived quite well in boxes that are very close to a square.  Brother Adams boxes were about square and Dadant was also fond of spherical shapes because he thought that was the most natural bee shape.    

I’m also seeing more condensation in my heat bubble designs as the aspect ratio increases.

My hives are not instrumented, so it’s hard to draw conclusions at this point, but what are you suggesting is the best shape?    

The "who" is the differential equations of heat and mass transfer...  Both brother adams and Dadant are wrong , both theoretically and experimentally,  and  to cap it all bees in trees are not  spheres.
More condensation at lower levels is a good sign. (despite what beeks say) condensation is not necessarily cold  but it always means a return of heat.

[deknow]

I think you are making this too complicated.

The bees cluster, forming a more or less solid mass in between combs, and in the cells of those combs...the bees are able to regulate the flow of air in and out (and within) the cluster.

When the temperature is cold, the bees do what they can to retain heat within the cluster....tighten up, limit air flow.

As soon as it is getting too warm in the cluster, the bees start to shed heat.

If you want to do an experiment, you can take a 5 frame nuc, screen the bottom and the top, and put it in the refregerator (or outside in the winter...somewhere around 30-40 degrees).  They make very little sound, very little heat is coming up through the screen, and very little smell is coming up through the screen.

As you warm them up, there is a "switch", where they go from holding the heat in to shedding it.  It is obvious from the sound, the heat, and the smell.

The size of the cluster determines their ability to keep the cluster warm.  If the cluster is too small or does not have "fuel", they will not be able to maintain their temperature.

Remember that the bees can be removing moisture from one cell to ripen honey, and increasing moisture in the next cell to keep the brood healthy.

If you want to talk about thermal flows within the hive, you have to take the comb, and the tens of thousands of little fans and heaters placed strategically throughout the combs.  It isn't as simple as a swimming pool, but it need not be complicated. 

More bees can maintain their temperature better than less bees.

Don't let condensation fall on the cluster...either with top cover design, absorbant material, or ventilation.

deknow

[derekm]

I think you are making this too complicated.

...

deknow

and your observations  assume no insulation..."ou can take a 5 frame nuc, screen the bottom and the top, "
with no insulation it is  much simpler... but not neccessarily desirable.

[Maryland Beekeeper]

Also, the ability and methods of cluster to regulate hive atmosphere is not well understood, if @ all. It is possible that heat/moisture loss through ventilated top and air movement around comb sides in most hives hamper this ability.
 Need more studies like this on different hive types:

http://www.sciencedirect.com/science/article/pii/S0022519311005698

Cheers,
Drew

p.s. I'm thinking colony atmospheric management might look something like this :

http://en.wikipedia.org/wiki/File:RayleighBernardConvection.png

[deknow]

..whether the details are well understood or not, it remains that the cluster does regulate the temperature of the cluster.  The cluster is able to do this under all kinds of conditions...hot, cold, insulated, not insulated, vented, sealed...etc.  The bees simply take care of things. 

They need to have enough honey to generate the heat they need, and they need to not have condensed moisture drip onto the cluster.

The experiment I proposed is an experiment, not a desirable way to keep bees.  It demonstrates quite viscerally how the cluster behaves at different ambient temperatures.  I proposed it the way I did because we did this experemet inadvertently driving some nucs north in a cargo van....and these were the conditions.

The study you cite is simply a computer model (with no testing of the results with real bees)...and a simplistic one at best:

For the purpose of modeling, each honeybee cluster was treated as an air-saturated porous medium with constant porosity. Heat and mass transfer interactions of the honeybees with the air, the outcome of metabolism, were captured in the porous medium model as source and sink terms appearing in the governing equations of fluid dynamics

There are undoubtedly differences between how air flows in frames and when comb is attached to the side walls of the cavity.  There are undoubtedly difference between how air flows in a hive with a top vent and a hive without.

...but these differences are best measured (if we want to know what they are) on bees, not in a simple computer model that treats the cluster as "an air saturated porus medium with constant porosity".

This is not a passive system...the bees maintain and modify the environment as needed...how the bees (indivudually  and as a cluster) react to various stimuli (cold, ventilation, sunlight, solar date, food stores, etc) is what is important.  I don't see the need to try to define the role of these components, as they appear to function as they should...they are adapted to maintain a suitable environment for the cluster.

deknow

[derekm]

...

" It demonstrates quite viscerally how the cluster behaves at different ambient temperatures. " ...

Yes that is correct but temperature is a too simple question.  Bees manipulate their environment therefore  subjecting them to overwhelming conditions hides their true behaviour which belongs in an insulated environment not at a forced  temperature .

I would suggest first quantitively understand bees real environment not the boxes Man puts them in

[deknow]

I would suggest first quantitively understand bees real environment not the boxes Man puts them in

What is it you think we don't understand?

deknow

[Finski]

I would suggest first quantitively understand bees real environment not the boxes Man puts them in

It is in Africa. What do you do with knowledge "bees in tree cavity in Africa".

Bees have never been in Finland, but now they are "in human made insulated box" .

You need not much understanding. You put the hive into polystyrene box, feed it full with sugar and wait then 8 months that willows start to bloom.

.

.

[derekm]

I would suggest first quantitively understand bees real environment not the boxes Man puts them in

It is in Africa. What do you do with knowledge "bees in tree cavity in Africa".

Bees have never been in Finland, but now they are "in human made insulated box" .

You need not much understanding. You put the hive into polystyrene box, feed it full with sugar and wait then 8 months that willows start to bloom.

They've been the UK and northern france since the last ice age. So their native environment predates skeps,  wooden and polystryrene boxes. Go re-read some research.

AND Why are you contradicting yourself, I distinctly remember you saying Apis Mellifera evolved to live in tree cqavities to colonise colder climtes

[Finski]

 I distinctly remember you saying Apis Mellifera evolved to live in tree cqavities to colonise colder climates

Go re-read some research.

You late born derekm,

Yes, I have read researches.

Before genemapping researchers believed that mellifera has evolved in Europe.

No one knows what has happened during ice age  ......since, how far since...

I wonder why we should research how bees live in tree holes.



.

[Finski]

.
Dec. 14, 2006 —

 The discovery of a 100-million-year old bee embedded in amber -- perhaps the oldest bee ever found -- "pushes the bee fossil record back about 35 million years," according to Bryan Danforth, Cornell associate professor of entomology.

Danforth and George Poinar of Oregon State University found the bee embedded in amber from a mine in northern Myanmar (Burma).

A report on this major fossil discovery, which the researchers say supports a new hypothesis in bee evolution, was published in the Oct. 27 issue of Science.

Scientists have long believed that bees first appeared about 120 million years ago -- but previous bee fossil records dated back only about 65 million years. Danforth and Poinar's fossil provides strong evidence for a more remote ancestry. The fact that the bee fossil also has some wasp traits suggests an evolutionary link between wasps and bees.

[derekm]

 I distinctly remember you saying Apis Mellifera evolved to live in tree cqavities to colonise colder climates

Go re-read some research.

You late born derekm,

Yes, I have read researches.

Before genemapping researchers believed that mellifera has evolved in Europe.

No one knows what has happened during ice age  ......since, how far since...

I wonder why we should research how bees live in tree holes.



.

well i have read the gene mapping research and they show the genetic changes that occurred since the honeybee  left africa and moved north via the iberian penisula.
btw nothing much evolves under an ice sheet...

[Finski]

well i have read the gene mapping research and they show the genetic changes that occurred since the honeybee 

Well done!!!!!