Ventilation

[Erichalfbee]

Can bees ventilate a hive more effectively with a solid floor and a small entrance or with an OMF?
Any ideas?
Please

 

[jenkinsbrynmair]

I'd guess (and it is a guess mind) that if the small entrance was a constant they'd do it easier with an OMF, but with a full size entrance maybe the solid floor would make it easier for them.

 

[Quis Custodiet]

A solid floor and full width entrance, as suggested above, would probably be the most efficient. Remember some air will have to enter the hive to replace that which is expelled.
Bees fanning on a OMF would be more likely to draw air from outside up through the floor and out the entrance, leaving the hot/foul air at the "ceiling" unmoved.
Your question is a very good one.

 

[Cussword]

leaving the hot/foul air at the "ceiling" unmoved.

Matchsticks anyone??

 

[For want of a better word]

Matchsticks anyone??

STIRRER !!!!

I would say that putting frames in the Warm Way would lead to dead spots as far as air movement within a sealed colony goes... I have found that in my WBC hives where I do not have a choice of frame orientation, that bees seem to cluster towards the entrance side, when in warm way... in hives of same ilk where the boxes are fitted the cold way there seems to be a general covering across all the frames.
Open mesh or solid floors do not seem to make any difference.

Biggest difference is siting.... LEY LINES ARE THE RULE

Yeghes da

 

[chrisb]

Matchsticks anyone??

Someone had to mention those

 

[REDWOOD]

Do they need to ventilate a hive with an open mesh floor? I have never seen any of my bees doing it.

 

[Webby]

STIRRER !!!!

I would say that putting frames in the Warm Way would lead to dead spots as far as air movement within a sealed colony goes... I have found that in my WBC hives where I do not have a choice of frame orientation, that bees seem to cluster towards the entrance side, when in warm way... in hives of same ilk where the boxes are fitted the cold way there seems to be a general covering across all the frames.
Open mesh or solid floors do not seem to make any difference.

Biggest difference is siting.... LEY LINES ARE THE RULE

Yeghes da

Do you actually go by lay lines? Are they not myth?

 

[Millet]

Do they need to ventilate a hive with an open mesh floor? I have never seen any of my bees doing it.

Do the bees not produce CO2 in the hive which is heavier than Oxygen, which means the Co2 will slowly fall from the hive while fresh air is drawn back in through the open mesh floor., just a thought but i will be wrong as usual..

 

[snelgrove]

Even with an open mesh floor air has to be circulated around the hive, bees still fan inside the hive to do this. With a solid floor bees are more numerous outside the entrance fanning, drawing air in.

 

[charlievictorbravo]

DerekM may be along in a minute to give the definitive word but my recollection of his presentation at Totnes last year was that most colonies in trees had enclosures that were tall (up to a metre or more) and 3 or 4 times bigger than their diameter, typically had a wall thickness of 10 to 15 cm and had one entrance at the bottom of < 40mm diameter.

If these figures are anywhere near typical, it does rather suggest that ventilation of a warm, well-insulated bee enclosure is a bit over-rated - how much ventilation could go out through a 40mm circular entrance?

CVB

 

[jenkinsbrynmair]

Do they need to ventilate a hive with an open mesh floor? I have never seen any of my bees doing it.

DerekM may be along in a minute to give the definitive word but my recollection of his presentation at Totnes last year was that most colonies in trees had enclosures that were tall (up to a metre or more) and 3 or 4 times bigger than their diameter, typically had a wall thickness of 10 to 15 cm and had one entrance at the bottom of < 40mm diameter.

If these figures are anywhere near typical, it does rather suggest that ventilation of a warm, well-insulated bee enclosure is a bit over-rated - how much ventilation could go out through a 40mm circular entrance?

CVB

My bees aren't in a frickin tree - they're in a hive!

I know some may say it's semantics but there is a difference between ventilation (fresh air for the colony) and circulation of air in general bees need to move air and water vapour around to ripen honey for one hence the reason for hives sounding like a pub cellar cooling system at the moment with all the fresh nectar going in. They're fanning like the clappers in all the hives at the moment (all OMF) with bees bearding outside to allow better movement of air - or in my case with underfloor entrances congregating in the lobby area like bingo players during a smoking break.
With a full width entrance (especially on solid floors) you will sometimes see a line of bees on one side with their backsides out fanning to expel air and on the other, heads out moving air in

 

[charlievictorbravo]

My bees aren't in a frickin tree - they're in a hive!

No, but they evolved largely in holes in trees. Bees weren't in hives that Langstroth discovered out in the woods one day. The point I was trying to make was that bees in a warm, well-insulated enclosure would appear to be able to manage with a lot less "ventilation" than most beekeepers think they need.

For a start the bee enclosure in a tree trunk would have a lot smaller temperature range - warmer in winter, cooler in a hot summer. How they cope in a tree space with removing high relative humidity air I don't know but they must do it.

CVB

 

[Gilberdyke John]

There are a few here now who are starting to hyper ventilate


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Site one of these on top of the hive, blowing downwards. Thats how you hyperventilate. https://www.alibaba.com/product-detail/Dynair-Air-Handling-Unit_138638649.html.

 

[Tremyfro]

I have observed...as you all have too...that the bees seal all the cracks, joints and interfaces in the hive. Some of them glue everything together with propolis. So my conclusion was that they didn't want any draughts...or they didn't want any unwanted visitors into the hive. Or even both.
They will propolise the edges of the OMF.
This year I have closed off the OMFs. The only time I have seen bees in great numbers at the entrance was after I reduced the entrances because of the wasps....they were on a flow and were queuing up to get in.
Yes you can hear them in the evening....but is this just the huge numbers of bees moving nectar about or is it them using their wings to mature the honey?
even with no OMF and the entrance closed down to an inch....they don't seem to have any problems capping the honey.
Most of the information about the reasons for bees fanning is anecdotal....it's interesting that when the bees are on a strong flow and the evening is warm...the air conditioner noise is strong but if the evening is cool...you can't hear it so much. Mainly, information can be found about pheromonal fanning. Anyone have information about research conclusions?

 

[jenkinsbrynmair]

Yes you can hear them in the evening....but is this just the huge numbers of bees moving nectar about or is it them using their wings to mature the honey?

It's them using their wings to mature the honey - observe and rfead is my suggestion

 

[wessexmario]

moving on to the original question (as the usual suspects have digressed yet again)

Can bees ventilate a hive more effectively with a solid floor and a small entrance or with an OMF?
Any ideas?
Please

Looking at the physical properties of the gases involved...

Carbon dioxide which the bees exhale is about 1.66 times as dense as air.
This means that given no fanning and normal respiration, the exhaled carbon dioxide will sink to the floor of the hive and spill out, either though the standard entrance, or the mesh floor. Air will flow in to replace it.
As most hives have the standard entrance at the bottom, whether or not they have an OMF floor or not, I would expect that the displacement would cause a good deal of circulation and exchange of air would occur naturally even without the bees fanning.

I haven't done any experiments with a beehive, but I know from brewing experience that opening a porthole on an industrial fermenter, if you place a candle below the porthole when opening it the CO2 will quickly spill out and extinguish the candle, so the tendency for CO2 to displace out is quite significant.

 

[jenkinsbrynmair]

I refer you to post #02 - it was going well up until that point.

it is blatantly obvious even to someone with an IQ of a cornflake that bees (for whatever objective) actively move air around the hive.

The original question was does an OMF have any advantages over a solid floor or vice versa

 

[TryingToLetThemBee]

moving on to the original question (as the usual suspects have digressed yet again)







Looking at the physical properties of the gases involved...



Carbon dioxide which the bees exhale is about 1.66 times as dense as air.

This means that given no fanning and normal respiration, the exhaled carbon dioxide will sink to the floor of the hive and spill out, either though the standard entrance, or the mesh floor. Air will flow in to replace it.

As most hives have the standard entrance at the bottom, whether or not they have an OMF floor or not, I would expect that the displacement would cause a good deal of circulation and exchange of air would occur naturally even without the bees fanning.



I haven't done any experiments with a beehive, but I know from brewing experience that opening a porthole on an industrial fermenter, if you place a candle below the porthole when opening it the CO2 will quickly spill out and extinguish the candle, so the tendency for CO2 to displace out is quite significant.

This is why tall people walk fast; the CO2 is down with the short-arses. Seriously, the candle trick works for unmixed gases but we are talking mixed here and those stay mixed.


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[Erichalfbee]

I ask as I was reading something about laminar flow and the way bees ventilate and it being rendered ineffective if the bottom of the box is open.