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Offline NZrebel

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Winter Ventilation for a Nuc
« on: October 21, 2015, 02:43:25 pm »
Hi, new to bees this year, first post on here so be gentle. :grin:

  I have a nuc, it has three 5 frame medium bodies full of bees, honey and pollen. The bottom board on it is solid, and i see a lot of advice to go to a screened bottom, even for winter, to allow ventilation.

   It seems to me that I understand the need for ventilation but also cringe at the though of the bottom of the hive being essentially open. I have the screened bottom board and I'm ready to put it on, just wanted to check with the collective....

   Dave


 

Offline OldMech

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Re: Winter Ventilation for a Nuc
« Reply #1 on: October 21, 2015, 10:28:07 pm »
Not sure how rough your winter is in Virginia?
   I am further north in Iowa. i winter nucs in two 5 frame medium boxes, or ten frames, five over five. No upper ventilation for a nuc, insulation on the cover. Two nucs pushed togehter and wrapped with tar paper. A shim with sugar cakes on top in case they run out of reserves, or cant reach the corners due to COLD weather...  because of the WIND and possible cold I stay away from screened bottom boards.
   In Virginia the winters may not be as cold and the winds less than 50+mph when its -20 degreez....
   Best bet is to talk to someone nearby and see how they do it if you can.
39 Hives and growing.  Havent found the end of the comfort zone yet.

Offline rwlaw

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Re: Winter Ventilation for a Nuc
« Reply #2 on: October 22, 2015, 08:29:07 am »
The debate is still on with SBB or solids.
Personally, solids. From experience, the queen doesn't lay in the bottom of the frames in colder weather and they're nothing but a pain in the butt to the hive in a dearth because of robbers trying to figure out how to get in thru the basement door. Dropped kicked them to the curb long ago.
Can't ever say that bk'n ain't a learning experience!

Offline Rurification

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Re: Winter Ventilation for a Nuc
« Reply #3 on: October 22, 2015, 09:09:29 am »
I started with screened bottom boards because it was the 'in' thing and got rid of them after losing all my bees 2 winters in a row.   I'm on solids now and the bees built up a lot better this year than previously.   Screens would be nice for one month during the summer when it's really hot, but the bees beard through it.   The rest of the time I'm happy with the solids.   And the solids do cut down on the robbing some like Rod said.
Robin Edmundson
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Offline NZrebel

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Re: Winter Ventilation for a Nuc
« Reply #4 on: October 22, 2015, 09:55:48 am »

  Thanks for the replies, all. Especially for your input on the solid board.

  I think I will repost this in General to see if I can figure out what local Virginia people do.

  Dave

Offline rookie2531

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Re: Winter Ventilation for a Nuc
« Reply #5 on: October 23, 2015, 07:41:56 pm »
I think a small upper hole in a shim full of sugar brick is better than open bottom. I have a dink, 5 frame medium and two 5 frame deeps that I'm going to try it with.

Offline little john

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Re: Winter Ventilation for a Nuc
« Reply #6 on: October 28, 2015, 06:25:57 pm »
I started with screened bottom boards because it was the 'in' thing and got rid of them after losing all my bees 2 winters in a row.   I'm on solids now ...

Isn't it interesting how methods vary in different locations ? I've been going in completely the opposite direction to yourself for the last few years: all my full-sized hives currently over-winter on 100% OMF's (SBB's) - albeit many have a 3-sided skirt below the mesh and a solid board below that - so there's very little draught 'up the skirt' as it were ...  But - zero winter losses during the last three years.
With regard to nucs - I originally built a number of 6-frame boxes with integral solid floors, but am currently retro-fitting them with 25% (floor area) mesh as they have become very wet inside and have started to grow mould.

LJ
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Offline Wombat2

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Re: Winter Ventilation for a Nuc
« Reply #7 on: October 28, 2015, 09:51:37 pm »
One of our Beek groups here published and article on condensation in hives - it was based on research done in the US Timber Industry in the 1920s ! Logic says hot air rises cold air descends but when you vent the hot air out the top condensation happens. They found that kiln drying lumber required that the vents should be at the bottom of the kiln. Hot then fills the kiln (hive) from the top down thereby pushing the cold moisture laden air out the bottom. Vented bottom boards therefore help reduce condensation particularly in the winter. Hot summers still need top ventilation as well as the ambient temperature is much higher and moisture levels in the air are lower.
David L

Offline rookie2531

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Re: Winter Ventilation for a Nuc
« Reply #8 on: October 28, 2015, 10:05:10 pm »
I've seen the same research when looking at making a solar dehydrator.

Offline OldMech

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Re: Winter Ventilation for a Nuc
« Reply #9 on: October 29, 2015, 10:16:15 pm »
My hives are apparently defective then...  no top vent I get a lot of ice build up around the edges.. I use foam on the top, Ice didnt build up there, but a lot of it built up around the edges and sides, to the point of freezing the outside frames in solid.  A small upper vent/entrance fixed that... it also fixed the ice dam that built up around the lower entrance... meaning.. i didnt have to worry about it anymore because they have an upper entrance for those upper 40 degree days.. so i dont have to go out and clear/chip entrances anymore...
   I think it has a lot to do with your location and humidity. Not to mention temps and the wind chill factor.
39 Hives and growing.  Havent found the end of the comfort zone yet.

Offline little john

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Re: Winter Ventilation for a Nuc
« Reply #10 on: October 30, 2015, 06:23:05 am »
One of our Beek groups here published and article on condensation in hives - it was based on research done in the US Timber Industry in the 1920s ! Logic says hot air rises cold air descends ...

Yep - and moist air also rises (that's why we get clouds in the sky) - warm, moist air doubly so - so what they discovered is counter-intuitive. I'd really appreciate links to any of the sources you may have - as this research sounds well-worth reading. Practice instead of theory.

LJ

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Offline little john

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Re: Winter Ventilation for a Nuc
« Reply #11 on: October 30, 2015, 06:38:06 am »
My hives are apparently defective then...  no top vent  [..]   
I think it has a lot to do with your location and humidity. Not to mention temps and the wind chill factor.

By sheer coincidence, a beekeeping colleague sent me scans of a few pages from Killion's 1951 'Honey in the Comb' last night. In those pages Kilion makes reference to living in Illinois - the next state to yourself - and his method of dealing with your severe winters was to retain a bottom entrance, but install pairs of hives inside 'flat-pack' winter packing cases, and adding additional straw. (well, it was the 1950's)  I don't know if you've come across this author ? Apparently he's well respected, although this is my first knowledge of the guy. His over-wintering success claims are impressive.  Just thought I'd chuck this 'in the pot' ...

LJ
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Offline little john

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Re: Winter Ventilation for a Nuc
« Reply #12 on: October 30, 2015, 11:15:01 am »
What I'm finding really interesting here, is how theory and practice are conflicting on this occasion:
Water has a molecular weight of around 18, whereas gaseous nitrogen has a molecular weight of around 28, and oxygen 32 - therefore molecules of water vapour are much lighter than dry air, and will rise. Which of course, is why we have clouds high up in the sky.

However, having done a search for appropiate terms using Google, I discovered a 1919 paper by Harry  D. Tiemann. Now Tiemann was no slouch when it came to chemistry - he even taught chemistry for a while - so would have been well aware of the molecular weight argument. However, on page 15 of his paper, he writes:
Quote
" ... evaporation is of itself a cooling operation, and calculation shows that the effect of evaporation is to increase the density of the humid air in spite of the fact that more vapor has therefore been added. [my emphasis] This means that there is a natural tendency of the air to descend as it passes through the lumber, particularly when rapid drying is taking place. The arrangement of the pile of lumber and the kiln, therefore, should be such as not to oppose but to assist the natural gravity tendency. Success or failure sometimes hinge on this point. Extensive observations under all kind of conditions and in all kinds of kilns have shown that this theory of the downward tendency of the air through the pile is the correct principle." 'Kiln Drying of Wood for Airplanes', 1919, Harry D. Tiemann

I think his wording of the above reveals that he is well aware that what he is saying runs contrary to what simple theory would otherwise suggest.

I think this finding must have profound implications for the reduction of humidity within beehives.

LJ
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Offline Duane

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Re: Winter Ventilation for a Nuc
« Reply #13 on: November 10, 2015, 09:25:31 pm »
Regarding kiln drying of wood, I'm just thinking things aren't the same as in the beehive.

It is true, that one of the reasons I have chosen top entrances is for hoping for the cooling effect in the summer.  As the bees bring in water to cool the hive, the coolness remains in the hive instead of "running out" the bottom entrance.  Also, as they evaporate the honey, the warm moist air rises out the top.  Does seem contradictory, but I haven't thought through all this completely.

However, with kiln drying of wood, I'm assuming they pipe in dry hot air.  As the dry hot air evaporates the moisture, it would have a cooling effect becoming heavier.  But this is different than in a beehive in winter, isn't it?  There's already moisture in the hive, it is warmed, so shouldn't it become lighter?

In other words, if you take moist air and add heat to it, it rises.  If you take dry air and add moisture to it, it sinks.  Am I right?

I could be all wrong here, but I think dry hot air in kiln drying can't be compared to what is happening in a beehive.  Easy to find out, though.  Have a 30 hives with top entrances and 30 with bottom in the same area(s), go through multiple winters, and see which ones have more moisture problems.

Offline little john

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Re: Winter Ventilation for a Nuc
« Reply #14 on: November 11, 2015, 05:08:19 am »
Regarding kiln drying of wood, I'm just thinking things aren't the same as in the beehive.
[...]
with kiln drying of wood, I'm assuming they pipe in dry hot air.

It's always a mistake to make such assumptions ...

Compared with beehives, the process is near-enough identical. I strongly suggest you read Tiemann's reports for the full story. There's no dry air involved at all - quite the contrary. During the drying process water is sprayed into the building to maintain a high humidity in order to slow-down and control the drying-out process. Hot dry air would only serve to dry the outside regions of the wood, leaving moisture at it's heart - this would cause cracking. Tiemann goes into great detail about this.

He even makes the point that describing the process as 'kiln-drying' is highly misleading, as most 'kilns' do indeed work on the principle of dry, very hot conditions.

As I've said - the process is near-enough identical - the object being to decrease the level of moisture in either wood or nectar by the use of raised temperature with it's accompanying rise in Relative Humidity. The 'kiln' building is fully sealed, with the only exit being for the condensed moisture via drains at it's base. Being thus sealed, the drying kiln is immune from variations in environmental humidity.  With beehives, the equivalent to drains for condensed moisture would be an OMF or bottom entrance.

Although obviously not intended as such, Tiemann's papers provide an explanation for how the honey bee is able to dry dilute nectar into hygroscopic honey by the use of modest heat, even when the hive is located within an area of persistent high humidity (such as my own).

LJ
 
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Offline Duane

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Re: Winter Ventilation for a Nuc
« Reply #15 on: November 12, 2015, 08:21:10 pm »
I guess I am wrong.  From a link on basement humidity:
http://www.northeastbasementsystems.com/about-us/news-and-events/370-does-humid-air-go-up-or-down.html
Quote
Well, according to Isaac Newton, in his book Opticks, (and USA Today) humid air is actually LESS dense than dry air.
I had no idea there was such a discussion over the issue. 

I searched but could not locate the Tiemann's papers.

So what you're showing is that if you have humid air, add heat to it, it sinks?  I still think there is more going on.  Do you have a link to the papers?

Something that stands out is where you said, "with the only exit being for the condensed moisture via drains at it's base."  Condensed?  What's causing it to condense?  There must be something cool in there.  And condensed water is different than humid air.  Need to know what's actually happening in the kiln.

Offline little john

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Re: Winter Ventilation for a Nuc
« Reply #16 on: November 13, 2015, 05:56:14 am »
I guess I am wrong.  From a link on basement humidity:
http://www.northeastbasementsystems.com/about-us/news-and-events/370-does-humid-air-go-up-or-down.html
Quote
Well, according to Isaac Newton, in his book Opticks, (and USA Today) humid air is actually LESS dense than dry air.
I had no idea there was such a discussion over the issue. 

I searched but could not locate the Tiemann's papers.

So what you're showing is that if you have humid air, add heat to it, it sinks?  I still think there is more going on.  Do you have a link to the papers?

Something that stands out is where you said, "with the only exit being for the condensed moisture via drains at it's base."  Condensed?  What's causing it to condense?  There must be something cool in there.  And condensed water is different than humid air.  Need to know what's actually happening in the kiln.

If you re-read my post of 30th Oct - the quote reads:

Quote
the effect of evaporation is to increase the density of the humid air in spite of the fact that more vapor has therefore been added. [my emphasis] This means that there is a natural tendency of the air to descend

It is the increased DENSITY of the moist air which results from evaporation which causes it to descend.

That is why a DYNAMIC evaporative system such as wood-drying or nectar drying cannot be directly compared to those other situations where evaporation is NOT taking place. In those other situations where heat is simply being applied, then warm moist air will certainly rise.

That is why a theoretical approach to the internal workings of a beehive as being a case of 'simple physics' is inadequate.  Much of science is like this - a single-variable approach is fine when considering static systems, but becomes fraudulent (in the Medawarian sense) when used in an attempt to explain dynamic systems where several variables may be in simultaneous operation. This is where the classic scientific method is totally inadequate, and why this work by Tiemann is so valuable - for he explains why an event which is counter-intuitive works in practice. The proof that he is correct can be found within a multi-billion dollar industry founded upon his discovery.

I have every sympathy (if that is the right word ...) for anyone who cannot get their heads around this idea of 'moist air generated from evaporation' actually descending rather than ascending, for this - I fully agree - is completely counter-intuitive, being in conflict with what happens within non-evaporative systems.

Tiemann's reports can be found at:
https://archive.org/details/theoryofdryingit00tiemrich
https://archive.org/details/kilndryingoflumb01tiem

And the report from which I quoted earlier in this thread:
http://naca.central.cranfield.ac.uk/reports/1920/naca-report-65.pdf

Hope you find this stuff enlightening ... :)

LJ
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Offline BeeMaster2

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Re: Winter Ventilation for a Nuc
« Reply #17 on: November 13, 2015, 01:36:57 pm »
Correct me if I am wrong, the evaporated air descends because it is cooled compared to the air in the kiln not because it has more moisture. The air in the kiln also has a high moisture content but is is warmer than the cooled evaporated air.
Thanks for posting that LJ.
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Offline Duane

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Re: Winter Ventilation for a Nuc
« Reply #18 on: November 26, 2015, 10:01:07 pm »
Ok, I've read more than I understand.  I now do understand there's a lot more going on in wood drying than I ever imagined!  Thanks for the link.

Now that I understand a little bit, I still think it cannot be compared to a hive.  What I understand the Theory of Drying saying is that heat evaporates the water (in the wood).  The heat must come internally or from other sources.  In the kiln, it comes in the form of superheated steam.  By heating the saturated water vapor above 212 degrees, the relative humidity becomes less, so it's not saturated any more.  "Dryer", relatively speaking.  As this superheated steam contacts the surface of the wood, the heat is transferred, reducing the steam to 212.  By applying enough heat to the wood, this evaporates the water in the wood.  But now that the steam is cooled it passes through the condenser and sprayer at which point it became more than I could fully understand.  Something about cooling, saturating, and then heating to reduce the relative humidity to start the process over again.

The reason the air descends, as sawdstmakr said, is because this superheated steam is now at a low of 212, no longer superheated, and cooler than the steam coming in.  But I would say the air in the kiln has a low relative moisture content.  The steam raised the saturation point.

Lot's of complex things going on there.  But how does all this relate to a hive?  The hive produces its own heat internally.  It is not superheated, meaning a phase shift is not happening. 

I agree that the theoretical approach is inadequate as there may be more things happening in a hive than thought of.  So why not test it?  But where Little John said, "This is where the classic scientific method is totally inadequate", I'm not sure I understand that.  The scientific method should be used in the case to find out.  I understand the scientific method to mean, test and observe.  For if we applied kiln drying theory to hives without testing, would that not be the theoretical approach?

Offline little john

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Re: Winter Ventilation for a Nuc
« Reply #19 on: November 27, 2015, 10:23:54 am »

Lot's of complex things going on there.  But how does all this relate to a hive?  The hive produces its own heat internally.  It is not superheated, meaning a phase shift is not happening. 
I'm not sure the source of heat is important - that a molecule of water vapour is generated by some means is where we could reasonably start an attempt to track what subsequently happens to that molecule.

Quote
Little John said, "This is where the classic scientific method is totally inadequate", I'm not sure I understand that. 
Inadequate for two reasons - firstly, because the classic scientific method invariably relies upon the manipulation of a single variable, yet in practice with biological systems, there may be multiple variables involved - especially with 'whole organism' biological systems (and when such organisms have intelligence, and may react independently), as opposed to studies of muscle fibres and so forth, which certainly do lend themselves to traditional biological experiments.

Secondly, the classic scientific method assumes that conducting an experiment does not change the scenario under investigation.

For a more in-depth explanation of these and other limitations of scientific enquiry, suggest you Google "Peter Medawar - Is the Scientific Paper a Fraud ?" [in which he concludes that it is]

Returning to the molecule of water vapour (gas) within a beehive scenario for a moment - it may well be the case that such a molecule descends due to an increase of density cause by evaporative cooling. Now if we accept that this is so, then the opposite dynamic will also occur - namely, if such a molecule comes into contact with a warm surface (such as a wax comb) or other molecules of warmed gas, then there will be a transfer of thermal energy such that the effects of the evaporative cooling become neutralised, and even reversed - with the molecule of water vapour once again becoming lighter than air, and ascending accordingly.

So - if this is anywhere near the case - it then becomes a 'percentage game' - with some water vapour molecules ascending and some descending - depending upon their individual temperatures.

I hope we can at least agree that this is a highly complex situation, and one in which there are probably no obvious answers.


I think this might be an appropriate moment to remind ourselves that exclusive logic (true or false, existence or non-existence, etc) is a human invention, a creation of Aristotle which was revived and taught from the 11th Century European Intellectual Renaissance onwards. Because we are introduced to such an idea during our formative years, we consider it to be unchallengeable. We talk about something being 'logical', as if it were transparently obvious and not really worthy of further examination.

But here we have a wonderful example (I think) of a non-Aristotelian system.
Question: "Does moist air rise - yes or no ?"
Answer: "Well, it all depends on what happens to individual molecules ..."

Question: "Is it best to have an upper or lower entrance to ventilate a hive ?"
Answer: "Either will work. There is no 'best'."

The idea of two opposite scenarios being equally valid may offend our sense of what is reasonable, and that one MUST be better than the other. There are many such ideas based on the primal concept of 'The One' which can also be traced back to Aristotle - so I blame him for any brain damage ... or rather those 11th Century monks.
:smile:

LJ
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Offline Duane

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Re: Winter Ventilation for a Nuc
« Reply #20 on: November 27, 2015, 12:35:22 pm »
I still say that what the link gave about how a wood drying kiln works is totally different than how a beehive works.  Now the result may or may not be the same do to complex systems involved which may differ in each. 

While under some circumstances, observation does influence what is being observed, are you saying there is no way to determine whether the humidity rises or falls in the hive?  Is there not a way to go about determining it without affecting the determination?

Quote
Question: "Does moist air rise - yes or no ?"
I don't think that would be the question to ask based upon the kiln drying link.  It's based upon the phase change of a liquid imparting heat to that being dried.  And it seems to emphasize it's not the "moist air" that's under consideration.  So I don't think that's the correct question for kiln drying.  It may be for a beehive.  But it's not the same process.

Quote
Question: "Is it best to have an upper or lower entrance to ventilate a hive ?"
Answer: "Either will work. There is no 'best'."
Sure, either "works".  But we can't determine whether there's a "best" without testing.

In crop breeding, there is no gene for "yield".  But there are for kernels, head size, pest resistance, etc.  All of those factors produce yield.  Rather than selecting for each individual component, breeders have great luck in selecting for yield. 

So with the hive, while there may be all kind of complex systems going on, even some unknown, cannot we find out whether a top entrance or a bottom entrance results in equal humidity or one having a better reduction of total humidity in the hive?  Why theorize when we can find out?

How would one go about determining humidity levels in a hive, top or bottom entrance, without affecting the observation?

Offline Eric Bosworth

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Re: Winter Ventilation for a Nuc
« Reply #21 on: November 28, 2015, 07:37:52 am »
"It is the increased DENSITY of the moist air which results from evaporation which causes it to descend.

That is why a DYNAMIC evaporative system such as wood-drying or nectar drying cannot be directly compared to those other situations where evaporation is NOT taking place. In those other situations where heat is simply being applied, then warm moist air will certainly rise."

Ok... by winter how much evaporation of nectar occurs? By then honey is capped. Do bees sweat in the cluster causing evaporation? In the summer or early fall I would agree that perhaps bee hives are a lot like wood kilns. In the winter I am not convinced. I will admit I have not yet finished reading the thread but if the theory is moisture from evaporation then it needs to evaporate from someplace. In the winter months there isn't a moisture source to evaporate. I would argue that the general air humidity is heated in the hive it rises, hits the cold top of the hive and condenses... or escapes out the top entrance. So unless you live in a dry climate the other method to prevent the problem is seal the hive. .. how do they breath at that point?

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Offline little john

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Re: Winter Ventilation for a Nuc
« Reply #22 on: November 28, 2015, 07:42:40 am »
I still say that what the link gave about how a wood drying kiln works is totally different than how a beehive works.  Now the result may or may not be the same do to complex systems involved which may differ in each. 

Quote
Question: "Does moist air rise - yes or no ?"
I don't think that would be the question to ask based upon the kiln drying link. It's based upon the phase change of a liquid imparting heat to that being dried.

I don't know from where you've got this idea that superheated steam - with it's phase-change etc - is the central principle of kiln-drying.

From the NACA-report-65.pdf (from an earlier link) p.14 :

Quote
METHODS OF SECURING CIRCULATION.

Pressure and superheated steam treatments are not suitable for airplane material: and the vacuum treatment, though suitable, is hardly practicable. It will, therefore, suffice to consider only atmospheric pressure treatments.

In general the circulation is produced in three ways:
(1) By external draught or ventilation, where the air is taken in from the outside, conditioned. passed through the kiln, and allowed to escape to the outside again.
(2) By recirculating the air within the kiln itself and removing the excess moisture by condensation.
(3) By forcing external air through the lumber by means of a fan or blower.

Combinations of these methods may also be used.

LJ
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Offline little john

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Re: Winter Ventilation for a Nuc
« Reply #23 on: November 28, 2015, 07:53:46 am »
Eric - ALL moist air has been generated by evaporation at some point in it's history. Evaporation IS the phase-change from liquid to gas - there is no other way of water entering the gaseous state.

What become relevant, is what happens to that moist air after it is generated: if it meets something warm as it descends, then some of it will undoubtedly ascend as a result. The remainder will continue to descend. As I said earlier, it then becomes a 'percentage game' - and if it should meet a really cold surface, then it will condense, i.e. undergo a phase change into liquid water.

Any of these may be used to eliminate moisture from the hive.  I prefer to encourage condensation, but it isn't the only way. If I lived in an environment where significant quantities of ice could build-up as a result, I'd probably go for top ventilation with the expense of some heat loss.

LJ
« Last Edit: November 28, 2015, 08:41:45 am by little john »
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Offline iddee

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Re: Winter Ventilation for a Nuc
« Reply #24 on: November 28, 2015, 10:59:15 am »
Although the above scenarios are interesting, I think the number one ingredient has been left out. That being, 20 to 30 thousand quads of little wings working as fans to direct the flow of air up one side and down the other. The temp and humidity don't come into play at all when the flow is controlled by force. Therefore, in my opinion, the natural flow of the heat created by the bees would be upward, top entrances would prevent the proper control when the fans "wings" slowed. I believe the bees have an easier job controlling the flow of air with lower entrances, and the bees natural selection on wild hives seem to support that. Having said that, I also believe smaller lower entrances, rather than SBBs, make it easier to control.
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Offline Eric Bosworth

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Re: Winter Ventilation for a Nuc
« Reply #25 on: November 28, 2015, 10:47:23 pm »
LJ I realize that all humidity must have evaporated from someplace. My point is that if the humidity inside the hive is because of high humidity outside the hive I fail to see the relavancy of the lumber kiln.

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Offline Duane

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Re: Winter Ventilation for a Nuc
« Reply #26 on: November 29, 2015, 11:27:30 am »
I still say that what the link gave about how a wood drying kiln works is totally different than how a beehive works.  Now the result may or may not be the same do to complex systems involved which may differ in each. 

Quote
Question: "Does moist air rise - yes or no ?"
I don't think that would be the question to ask based upon the kiln drying link. It's based upon the phase change of a liquid imparting heat to that being dried.

I don't know from where you've got this idea that superheated steam - with it's phase-change etc - is the central principle of kiln-drying.
From
https://archive.org/details/theoryofdryingit00tiemrich
starting on page 14, titled "Evaporation in the Absence of Air".

"...a wet piece of wood has been heated in saturated steam to 212F.  No evaporation will take place until additional heat is added.  Now, suppose steam superheated to 232F or 20 of superheat is introduced.  The portion immediately in contact with the surface of the wet wood will be cooled to 212F., and in so doing it will vaporize a certain portion of water from the surface...."

 Further down in the presense of air, the air and steam imparts heat to the wood raising the temperature of the wood as it dries.

As I understand it, no wood drying occurs until steam condenses upon it.  Gas to liquid.

It also generalizes superheated steam to be "vapor present in the air at any humidity less than saturation is really 'superheated steam'", page 9.

Therefore whether above 212 or not, the wood must be cooler than the moist air so the phase change can happen.  The wood is dried by raising its temperature by having warmer air condense upon it.

Which is absolutely not what you want happening in a bee hive.  You don't want warm air condensing on cooler honey to evaporate it.  And when all the honey is capped, nothing is being evaporated other than the respiration of the bees.  And they take care of that evaporation.  They only need for it to be eliminated.

Am I missing something here?


And as iddee pointed out, the bees affect the air currents, too. 

Should there be any objection to testing it and finding out?

Offline jayj200

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Re: Winter Ventilation for a Nuc
« Reply #27 on: November 29, 2015, 01:08:15 pm »
So who has tried thin follower boards on the outsides of the hive? making a cooler exhaust evaporator, moister eliminator,yes this would work

Offline Eric Bosworth

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Re: Winter Ventilation for a Nuc
« Reply #28 on: November 29, 2015, 04:32:15 pm »
Jayj200 I can't quite figure out what you mean.  A box in a box? Condensation on the outside box dry  bees inside the inner box? I'm not sure what a follower board on the outside would look like.

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Offline derekm

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Re: Winter Ventilation for a Nuc
« Reply #29 on: January 12, 2016, 02:54:01 pm »
My hives are apparently defective then...  no top vent I get a lot of ice build up around the edges.. I use foam on the top, Ice didnt build up there, but a lot of it built up around the edges and sides, to the point of freezing the outside frames in solid.  A small upper vent/entrance fixed that... it also fixed the ice dam that built up around the lower entrance... meaning.. i didnt have to worry about it anymore because they have an upper entrance for those upper 40 degree days.. so i dont have to go out and clear/chip entrances anymore...
   I think it has a lot to do with your location and humidity. Not to mention temps and the wind chill factor.
you should have insulated the sides  and made a 6" long insulated entrance
your target is around 1/5 to 1/8 the heat loss of a standard hive
If they increased energy bill for your home by a factor of 4.5 would you consider that cruel? If so why are you doing that to your bees?

Offline derekm

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Re: Winter Ventilation for a Nuc
« Reply #30 on: January 12, 2016, 03:03:26 pm »

Lot's of complex things going on there.  But how does all this relate to a hive?  The hive produces its own heat internally.  It is not superheated, meaning a phase shift is not happening. 
I'm not sure the source of heat is important - that a molecule of water vapour is generated by some means is where we could reasonably start an attempt to track what subsequently happens to that molecule.

Quote
Little John said, "This is where the classic scientific method is totally inadequate", I'm not sure I understand that. 
Inadequate for two reasons - firstly, because the classic scientific method invariably relies upon the manipulation of a single variable, yet in practice with biological systems, there may be multiple variables involved - especially with 'whole organism' biological systems (and when such organisms have intelligence, and may react independently), as opposed to studies of muscle fibres and so forth, which certainly do lend themselves to traditional biological experiments.

Secondly, the classic scientific method assumes that conducting an experiment does not change the scenario under investigation.

For a more in-depth explanation of these and other limitations of scientific enquiry, suggest you Google "Peter Medawar - Is the Scientific Paper a Fraud ?" [in which he concludes that it is]

Returning to the molecule of water vapour (gas) within a beehive scenario for a moment - it may well be the case that such a molecule descends due to an increase of density cause by evaporative cooling. Now if we accept that this is so, then the opposite dynamic will also occur - namely, if such a molecule comes into contact with a warm surface (such as a wax comb) or other molecules of warmed gas, then there will be a transfer of thermal energy such that the effects of the evaporative cooling become neutralised, and even reversed - with the molecule of water vapour once again becoming lighter than air, and ascending accordingly.

So - if this is anywhere near the case - it then becomes a 'percentage game' - with some water vapour molecules ascending and some descending - depending upon their individual temperatures.

I hope we can at least agree that this is a highly complex situation, and one in which there are probably no obvious answers.


I think this might be an appropriate moment to remind ourselves that exclusive logic (true or false, existence or non-existence, etc) is a human invention, a creation of Aristotle which was revived and taught from the 11th Century European Intellectual Renaissance onwards. Because we are introduced to such an idea during our formative years, we consider it to be unchallengeable. We talk about something being 'logical', as if it were transparently obvious and not really worthy of further examination.

But here we have a wonderful example (I think) of a non-Aristotelian system.
Question: "Does moist air rise - yes or no ?"
Answer: "Well, it all depends on what happens to individual molecules ..."

Question: "Is it best to have an upper or lower entrance to ventilate a hive ?"
Answer: "Either will work. There is no 'best'."

The idea of two opposite scenarios being equally valid may offend our sense of what is reasonable, and that one MUST be better than the other. There are many such ideas based on the primal concept of 'The One' which can also be traced back to Aristotle - so I blame him for any brain damage ... or rather those 11th Century monks.
:smile:

LJ
this a calumny, Science is not cofined to a single variable, consider computational fluid dynamics,  the research involving milllions or variables!And Peter Medawar - Is the Scientific Paper a Fraud does not reach that conclusion. His conclusion is that the structure of the scientific paper does not represent the structure of scientific thought. A very different thing.
If they increased energy bill for your home by a factor of 4.5 would you consider that cruel? If so why are you doing that to your bees?

Offline Colobee

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Re: Winter Ventilation for a Nuc
« Reply #31 on: January 15, 2016, 09:08:29 pm »
...Killion's 1951 'Honey in the Comb' ... In those pages Kilion makes reference to living in Illinois - the next state to yourself - and his method of dealing with your severe winters was to retain a bottom entrance, but install pairs of hives inside 'flat-pack' winter packing cases, and adding additional straw. (well, it was the 1950's)  I don't know if you've come across this author ? Apparently he's well respected....His over-wintering success claims are impressive....

Yes- a well respected and often cited beekeeper of the time, frequently quoted in the mainstay literature.  He is the author of "The production of Comb Honey and Bulk Comb Honey" Chapter of  "The Hive and the Honey Bee", 1975. The decline in interest for comb honey doesn't diminish his many observations and techniques.
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Offline little john

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Re: Winter Ventilation for a Nuc
« Reply #32 on: January 16, 2016, 05:13:31 pm »
this a calumny, Science is not cofined to a single variable,  ...

I find that accusation offensive, but nothing less than I've come to expect from someone so blinkered.

As you well know, I didn't say science was confined to a single variable - what I said was "the classic scientific method invariably relies upon the manipulation of a single variable , yet in practice with biological systems, there may be multiple variables involved ...", and so on.

When research chemists come across the interesting use of a herb, for example - what do they immediately do ?  Attempt to isolate the "active ingredient" (singular) - that's single-variable thinking in action.

Another example - to keep this vaguely on-topic - "what constitutes the ideal swarm trap ?" Most people will say a cavity of around 40 litres in size. Where does this idea come from ? From an experiment conducted by Thomas Seeley - in which he sets out to determine what size nest cavity bees prefer. Size of course, being a single variable. I have every sympathy for this approach, for biological experiments involving more than one variable would be unwieldy, difficult, and very time-consuming to conduct.

But the problem with such single-variable experiments is that they rarely present the whole truth, and in the case of Seeley's experiment - the work was fraudulent (in the Medawarian sense) precisely because Seeley had pre-determined that cavity size was the only important factor to be considered, and had duly set out to determine what that size was. The paper was written-up and published in the form which Medawar describes as fraudulent: "the scientific paper is a fraud in the sense that it does give a totally misleading narrative of the processes of thought that go into the making of scientific discoveries."

There are many other variables which could be equally valid in the case of nest cavities: height from the ground; cavity shape; colour, entrance size; smell,  and so on ...  But no - that experiment focussed (as thousands of similar experiments do) exclusively upon one single variable - one which has been pre-determined to be of importance.  Medawar again: " ... all scientific work of an experimental or exploratory character starts with some expectation about the outcome of the inquiry." (You see, there is far more to Medawar's paper than just it's conclusion)

A more complete narrative was to later emerge when Seeley wrote a book which included a story about the truth of what actually happened. The experiment was conducted on a barren island, so that the bees could not be distracted by trees or other potential nesting places. That was good 'scientific' thinking, but totally divorced from reality, as such places do not allow bees to behave naturally.

And did the bees choose one size cavity over another ? No, they did not - at least not when allowed to. They flew clean away from the experimental site and set-up home in a chimney above the only building on that otherwise deserted island !

That was a golden opportunity to make an original discovery of merit - that there may be something about a chimney (size, shape, smell - who knows ?) - but it was by-passed by an agenda of prejudice (the pre-judging that cavity size was the sole factor of importance).

It was only after that chimney had been sealed, that the experiment could be continued. Is this really valid science ? Well, yes it IS - and that's my beef about much biological enquiry - because it is so often predicated upon a completely unrealistic and unnatural setting - and thus becomes a game which involves strict rules about what information can be revealed, and in what form.

I know you to be a person who is preoccupied with the single variable of heat, and issues of insulation - but again I stress - biological systems such as beehives involve multiple variables, and to complicate matters further, some of these emanate from intelligent responses of the organisms under examination.

The craft of beekeeping is an art, and lends itself very poorly to traditional scientific enquiry.

LJ
A Heretics Guide to Beekeeping - http://heretics-guide.atwebpages.com

Offline derekm

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Re: Winter Ventilation for a Nuc
« Reply #33 on: January 29, 2016, 06:24:33 pm »
I still hold to this being calumny and now it is directed at myself.
   I am interested in heat transfer in honeybee nests.
This involves the shapes of the hive/enclosure and postion of the heatsource/bees, the position of the openings, the properties of the materials, the airflow inside the hive and the air flow outside the hive, the variation of heat production with temperature, The variation of heat flux. A complex multidimensional problem that needs sophisticated visualisation tools such as Paraview. http://www.paraview.org/
  Science at least the science i am involved in is multidimensional. If you think its a single variable then that reflects your knowledge and perception  not reality
   
An example here is a multidimensional paper ...

J Theor Biol. 2012 Feb 21;295:168-93. doi: 10.1016/j.jtbi.2011.11.007. Epub 2011 Nov 25.
Flow currents and ventilation in Langstroth beehives due to brood thermoregulation efforts of honeybees.
Sudarsan R1, Thompson C, Kevan PG, Eberl HJ.

« Last Edit: January 29, 2016, 06:43:37 pm by derekm »
If they increased energy bill for your home by a factor of 4.5 would you consider that cruel? If so why are you doing that to your bees?

Offline Duane

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Re: Winter Ventilation for a Nuc
« Reply #34 on: March 31, 2016, 06:02:41 pm »
My three hives made it through winter.  When looking this spring, I noticed that there was mold on the top cover much like the hive I had with a bottom entrance.  I had narrowed my top entrances.  I am thinking that when you have warm moist air that contacts cold surfaces, you have condensation.  It doesn't matter that you have top or bottom entrances, unless you have the top completely off.  The only difference is that perhaps the moist air would not remain within the hive with a top entrance.

Offline Dabbler

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Re: Winter Ventilation for a Nuc
« Reply #35 on: April 01, 2016, 05:25:18 pm »
I thought it was odd that none of the researchers had done humidity measurements in a hive so I went looking and found that they had:

http://repository.up.ac.za/bitstream/handle/2263/28357/dissertation.pdf?sequence=1&isAllowed=y

I am still slogging through the report.
However Iddee's comments about the thousands of little fans is very valid and is echoed in the thesis.
The bees do apparently actively regulate the humidity within the hive.
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