insulation in hive

[Davelin]

Somerset is tropical..

with monsoon thrown in!!

 

[user 6228]

with monsoon thrown in!!

exactly its heat loss not temperature thats the issue. heavy rain and wind take the heat away at +5C.

unfortunately combs outside the cluster with clear air all around (bee space)dont do anything for insulation.

 

[Davelin]

unfortunately combs outside the cluster with clear air all around (bee space)dont do anything for insulation.

Disagree with you here.
Still air is an excellent insulator, it's the main constituent of the insulation on your hives. Bee space is too small for significant convection currents, so any empty frames and spaces at the side must help insulation. Put your hand on a cold wall, and then 2" away and spot the difference.

 

[oliver90owner]

an empty frame will contain cells full of trapped air, which is about the best insulator you can get.-

Two things. Normally at this time of the year those outermost frames will be filled with honey - otherwise the beekeeper failed in the autumn. While air might have a very low coefficient of thermal conduction, it is most certainly not a lot of good where convection is concerned, unless retained in a cellular, or similar, matrix where the movement of the gas is prevented.

Also the analogy is flawed. It demonstrates only that the air 50mm from a cold wall is close to ambient room/box temperature, which is what I would expect. Try checking for cold down-draughts at the bottom of a single glazed window; that is due to conduction from the air followed by the fluid movement carrying the cooled air downwards. Same will happen in a hive, possibly with extra latent heat of condensation in the water-laden air being absorbed by the hive walls.

 

[MuswellMetro]

http://www.beekeepingforum.co.uk/attachment.php?attachmentid=9491&d=1390522898

That second paper strikes me as a very odd experiment ... putting sheets of metal above and below the frames in order to collect condensation ... now, I'm no scientist but isn't metal one of the best conductors of heat ... I don't know many beekeepers who have hives with metal plates in them ... most hives are (and have always been) constructed from low thermal conductance materials. I would have thought that metal sheets inside the hive would have been a cause of condensation as well as a method of measuring it ?

My fully insulated hive has a mesh floor and an 8mm polycarbonate crownbaord sealed to the top of the hive immediately over the frames, and there's 100mm Kingspan on top of that. I see no condensation forming inside the hive ....

pargyle, the metal conductors are there to see the dynamics of a hive and metal i used so heat is conducted away and therefore you an see were the water vapour that the bees produce actual is in the hive , it is not saying put metal plates in your hive

most wooden box beekepers follow Wedmore's advise that is on the assumption that warm moist air exits the cluster at the top and rises to the top of the hive ( the bees produce water converting honey to energy/heat), Therefore Wedmores and many in the BBKA vent the top of the hive with matvchsticks under the crown board to let the water vapour out,

wheras the paper shows that B Mobus was correct in his calulation disproving wedmores theories, and that it is better to vent the bottom as heavy water vapur exits the cluster underneath the cluster and decnds as it cools

The dynamics in a polyhive or your self made insulated hive and it shows it is better to vent the bottom of the hive wth a OMF than top ventalation

 

[pargyle]

pargyle, the metal conductors are there to see the dynamics of a hive and metal i used so heat is conducted away and therefore you an see were the water vapour that the bees produce actual is in the hive , it is not saying put metal plates in your hive

I understand that ... I was questioning the validity of an experiment that uses metal plates inside a hive (metals being excellent conductors and thus a focus for condensing atmospheric moisture) ... not just moisture condensed from the ripening of honey. Perhaps I didn't make myself clear ?

most wooden box beekepers follow Wedmore's advise that is on the assumption that warm moist air exits the cluster at the top and rises to the top of the hive ( the bees produce water converting honey to energy/heat), Therefore Wedmores and many in the BBKA vent the top of the hive with matvchsticks under the crown board to let the water vapour out,

Yes ... I realised early on in my hive design stage (from my basic physics) that Wedmore was up the creek ...

wheras the paper shows that B Mobus was correct in his calulation disproving wedmores theories, and that it is better to vent the bottom as heavy water vapur exits the cluster underneath the cluster and decnds as it cools

The dynamics in a polyhive or your self made insulated hive and it shows it is better to vent the bottom of the hive wth a OMF than top ventalation.

Exactly why my hive was constructed as it is ... I followed B Mobus with some interest ....

Sorry MM ...wasn't arguing any of the points raised - and I agree totally with the findings ... just wasn't sure about the methodology of the experimental side of things ...

 

[user 6228]

Disagree with you here.
Still air is an excellent insulator, it's the main constituent of the insulation on your hives. Bee space is too small for significant convection currents, so any empty frames and spaces at the side must help insulation. Put your hand on a cold wall, and then 2" away and spot the difference.

You are mistaken.

I am observing and measuring this type scenario every day.

Once the air is heated its no longer still and 4mm is more than sufficient for convection. and doubly so if there are gaps on the top and on the botton

You obviously dont believe me.
So answer these questions

Why do you think buildings are pressure tested?
why do you have to tape seal insulation joints to meet building regs?
why is insulation foam lots of tiny isolated bubbles and not big ones?


I have a test rig here where I have to carefully seal every habitat that i test, to get repeatable results.

small gaps matter. Bees know this.

The match stick under the roof , a 1.5mm gap, loses 50% of the heat even in wooden hive.

if you are in the area I will set up a hive with combs and put in a heater and two frames of temperature measuring devices and we will be able to see what temperature difference we get...

 

[MuswellMetro]

p

I understand that ... I was questioning the validity of an experiment that uses metal plates inside a hive (metals being excellent conductors and thus a focus for condensing atmospheric moisture) ... not just moisture condensed from the ripening of honey. Perhaps I didn't make myself clear ?~~~~~

Sorry MM ...wasn't arguing any of the points raised - and I agree totally with the findings ... just wasn't sure about the methodology of the experimental side of things ...

it is not measuring water from ripening honey, the hives are in over winter state, see the first sentence of the abstract, the experiment was to measure atmospheric moisture around the winter cluster ( I expect your hive is so well insulated that your bees can ripen honey in January ), but i agree they could have used a most modern approach such as measure humidity and temperature with a movable probe

i agree with you insulated hive is the future but i am not going to throw away twenty 14x12

 

[Davelin]

You are mistaken.

I am observing and measuring this type scenario every day.

Once the air is heated its no longer still and 4mm is more than sufficient for convection. and doubly so if there are gaps on the top and on the botton

You obviously dont believe me.
So answer these questions

Why do you think buildings are pressure tested?
why do you have to tape seal insulation joints to meet building regs?
why is insulation foam lots of tiny isolated bubbles and not big ones?


I have a test rig here where I have to carefully seal every habitat that i test, to get repeatable results.

small gaps matter. Bees know this.

The match stick under the roof , a 1.5mm gap, loses 50% of the heat even in wooden hive.

if you are in the area I will set up a hive with combs and put in a heater and two frames of temperature measuring devices and we will be able to see what temperature difference we get...

I'm not arguing with any of this. You said frames don't do anything for insulation.
That's what I disagree with.
A cluster sitting on the wall of a hive is going to lose more heat through the side than one two frames in whether the frames are full or empty.

Your insulation around the sides is clearly going to act as a much better insulator, but do we need all that here in tropical Somerset?

 

[user 6228]

I'm not arguing with any of this. You said frames don't do anything for insulation.
That's what I disagree with.
A cluster sitting on the wall of a hive is going to lose more heat through the side than one two frames in whether the frames are full or empty.

Your insulation around the sides is clearly going to act as a much better insulator, but do we need all that here in tropical Somerset?

Well if you dont want the increased honey and faster spring start up and reduced occurance of nosema and chalkbrood. Perhaps you would like smaller colonies to have a greater chance of winter survival?

 

[MartinL]

it wont freeze inside... this side of -20C the roof is waterproof it is tape sealed inside and out for insulation purposes...a sheet of ally on the top is to only prevent pooling on the foil surface, and damage from birds landing on it.

water wood rotting ? how is that different from rain on an exposed hive?

Why go to all that bother with "insulation" then cover it all in one of the best conductors available, ie Aluminium????!

 

[itma]

pargyle, the metal conductors are there to see the dynamics of a hive and metal i used so heat is conducted away and therefore you an see were the water vapour that the bees produce actual is in the hive , it is not saying put metal plates in your hive

most wooden box beekepers follow Wedmore's advise that is on the assumption that warm moist air exits the cluster at the top and rises to the top of the hive ( the bees produce water converting honey to energy/heat), Therefore Wedmores and many in the BBKA vent the top of the hive with matvchsticks under the crown board to let the water vapour out,

wheras the paper shows that B Mobus was correct in his calulation disproving wedmores theories, and that it is better to vent the bottom as heavy water vapur exits the cluster underneath the cluster and decnds as it cools

IMHO, it *is* a very strange experiment, and is being strangely interpreted!

They didn't record the temperature of their condensers!

We would expect the top condenser to be warmer - and therefore condense out less water. No news there.
Buried deep in the Discussion section, the authors seem to be admitting exactly that

A condenser above the cluster collected far less water than the one below the cluster (Fig. 2). The upper condenser was probably heated by the warm air raising from the cluster, which decreased its ability to condense humidity. The bottom condenser had always been cooler due to being placed under the nest of bees and could thus condensate the water very efficiently.

My emphasis.
The reduced condensation on the top, as opposed to bottom, is explained by the temperature difference - not where the most moist air might be.


Oddly enough, I've wondered about having a deliberately condensing cold point (like a stainless bolt through the wall), about 2/3 of the way down the hive. This would somewhat knock down the overall humidity in the hive, and ensure a condensation (drinking) point where it would cause no harm to the bees.




I'm a definite advocate of UK bee wintering with a mesh floor, closed crownboard and sufficient insulation above the crownboard to prevent condensation on the crownboard, as that would drip onto the bees and down through the whole hive.
Condensation that is both below the cluster and on the walls, should be a benefit to the bees (drinking without leaving the hive) and no harm - excess condensation simply draining out through the mesh floor.

 

[itma]

Why go to all that bother with "insulation" then cover it all in one of the best conductors available, ie Aluminium????!

Actually, if you think about it, the ally sheet isn't going to be any colder than the air temperature, and thus it isn't going to *harm* the insulation performance of what is below it.
However, the non-smooth foil coating on the Recticel does actually, by trapping small pools of water that must be evaporated off, make the surface occasionally cooler than the air temperature.
The easy-drain property of the sheet metal improves the insulation performance under those conditions.
And it is tough enough to resist damage from vandal birds. (Which Recticel isn't.)

A layer of hard sheet plastic would add to the insulation (very slightly), but it might through higher emissivity radiate more heat.
The thing to get your head around is that the Aluminium isn't making the insulation beneath work any less well. And in wet conditions, it will actually help it to work better!

 

[MuswellMetro]

IMHO, it *is* a very strange experiment, and is being strangely interpreted!

They didn't record the temperature of their condensers!

.

Agree, reviewing it, it now looks rather amateurish

, I can see me ,doing my own experiment as i have three temp/humidity sensors in the cupboard

 

[user 6228]

Actually, if you think about it, the ally sheet isn't going to be any colder than the air temperature, and thus it isn't going to *harm* the insulation performance of what is below it.
However, the non-smooth foil coating on the Recticel does actually, by trapping small pools of water that must be evaporated off, make the surface occasionally cooler than the air temperature.
The easy-drain property of the sheet metal improves the insulation performance under those conditions.
And it is tough enough to resist damage from vandal birds. (Which Recticel isn't.)

A layer of hard sheet plastic would add to the insulation (very slightly), but it might through higher emissivity radiate more heat.
The thing to get your head around is that the Aluminium isn't making the insulation beneath work any less well. And in wet conditions, it will actually help it to work better!

In my implementation I leave a small air gap between the recticel and the aluminium.

 

[pargyle]

it is not measuring water from ripening honey, the hives are in over winter state, see the first sentence of the abstract, the experiment was to measure atmospheric moisture around the winter cluster ( I expect your hive is so well insulated that your bees can ripen honey in January ), but i agree they could have used a most modern approach such as measure humidity and temperature with a movable probe

i agree with you insulated hive is the future but i am not going to throw away twenty 14x12

Ahhh ... just re-read the paper - see what you mean ! There must have been loads of variables that could not be accounted for with such a basic methodology ... makes my £13 temperature and humidity meter look quite sophisticated !!

Perhaps there's no need to throw away your 14x12 hives ... DerekM's Kingspan 'hive bonnets' seem to be the answer ... best do a bit of skip diving ... bound to be some Kingspan in the skips on any building site or house renovation these days !

 

[charlievictorbravo]

it is not measuring water from ripening honey, the hives are in over winter state, see the first sentence of the abstract, the experiment was to measure atmospheric moisture around the winter cluster ( I expect your hive is so well insulated that your bees can ripen honey in January ), but i agree they could have used a most modern approach such as measure humidity and temperature with a movable probe

i agree with you insulated hive is the future but i am not going to throw away twenty 14x12

I confirm you don't need to throw you 14x12s away - make what I call "Hive Cozies" for them, like I did for my 14x12 - see attached photo of mine. There's 100mm celotex on the top and 50 mm around the sides. It has a thin aluminium roof to shed rainwater.
The insulation is dowelled together and the whole is covered in Aldi duct tape, paying particular attention to the joints.
The big question for me, on which I have had conflicting advice, is whether or not to leave the monitoring board in place over winter. My gut feeling is to remove on still days and leave it in when it's windy. My reasoning is that wind turbulence around the hive could draw out warm air from the hive whereas in periods of sustained calm weather, the hive would retain its heat by normal convection processes.

CVB

 

[oliver90owner]

The big question for me, on which I have had conflicting advice

Read the appropriate part of the John Harding book. You should learn all you need to know from that.

You would then not need to filter all the conflicting and inappropriate advice you get from some on here.

I'm glad you dowelled your plastic parts; better than either nails or screws - as long as they were of an appropriate material. I would think the biggest problem is to stop them blowing away in the recent gales.

RAB

 

[Ely]

Do open mesh floors make the hive colder over winter? I use them with sealed crownboard and top insulation

 

[user 6228]

Do open mesh floors make the hive colder over winter? I use them with sealed crownboard and top insulation

In still air it depends. A classical shallow floor with bottom of the entrance at mesh level the answer is at the bottom of the heat source (e.g. bee cluster) any difference disapears into the measurement error.

Thats as far as I've got
.
The explanation is all about convection cells and stratification.

in wind conditions and different configurations it is probably different