Supers/Heatloss

[lebouche]

Hi,
If bees try and keep brood at around 93F then surely adding an empty super above them creates heat loss?
Wouldn't it be better to add a crown board first, and if not using excluders perhaps discourage spread of brood to supers?

 

[itma]

No, not better - "going through the hole" tends to make them think that the space beyond is 'outside' the hive.

Use a polyhive, or add insulation under the roof (or both) if you think that heat loss from the super(s) matters.

 

[Graham40]

The cluster regulates the temperature if its not damp its not going to matter how much empty space is above, in summer its usually overheating of the brood that occurs, hence the bees out on the landing board fanning away like mad, they're circulating the air round the hive.

 

[Lorenz]

At this time of year, I don't worry about this, but I do in the Spring when the nights are cold. If it is cold at night, but will be sunny and there is a flow on in the day, and I think that they will need a super very soon, but perhaps not today, I put a sheet of newspaper under the empty super, and then they go up when they are ready. Perhaps you are somewhere like the Falklands where it gets very windy and cold at night?

 

[lebouche]

At this time of year, I don't worry about this, but I do in the Spring when the nights are cold. If it is cold at night, but will be sunny and there is a flow on in the day, and I think that they will need a super very soon, but perhaps not today, I put a sheet of newspaper under the empty super, and then they go up when they are ready. Perhaps you are somewhere like the Falklands where it gets very windy and cold at night?

Thanks for the replies. Not the Falklands....., I'm London and Berkshire but it's currently 16C where my hives are. Way off the 34C or whatever 93F is that the brood is supposed to be kept at.

 

[Finman]

Hi,
If bees try and keep brood at around 93F then surely adding an empty super above them creates heat loss?

You may put the the expansion box under the brood. So bees can keep the heat of brood steady. So bees have place where to put pollen and nectar.
When you give third box, then the colony is stronger to keep the brood heat.

.

 

[itma]

The cluster regulates the temperature if its not damp its not going to matter how much empty space is above, in summer its usually overheating of the brood that occurs, hence the bees out on the landing board fanning away like mad, they're circulating the air round the hive.

Firstly, as derekm will surely be along to point out soon, any extra effort the bees expend in heating (or cooling) is reflected in a reduction in the honey crop.
They will use more 'fuel' so there will be a smaller surplus (or the beekeeper will have to provide {even} more sugar).
Insulation reduces heat loss all the time that the outside temperature is below about 33C, making for an increased crop.

Secondly, I'm sure the temperature in Aberdeen does get above 33C.
But not often enough to worry about.

 

[Finman]

The cluster regulates the temperature if its not damp its not going to matter how much empty space is above, in summer its usually overheating of the brood that occurs, hence the bees out on the landing board fanning away like mad, they're circulating the air round the hive.

Quite not so...

.And you hives are over heating? How often this summer your temps have went over 20C?

I ahve used 10 years electrict heating on the bottom of all hives. It teaches how importnat is temperature to the hive, even to 4 box hive. It helps to make bigged broo ball radius.

Lets think that radius is 15 cm. Then it expands to 20 cm. Radius is 30% more. How much more is the ball volume.

radius 15 cm ---> ball volume 14 100
radius 20 cm ---> ball volume 33 500

the volume is 2.4 fold

.

 

[Graham40]

Who said anything about external temperature, its internal temperature in the broodnest you've got to worry about have a good look at your hives next time.

Bigger the broodnest the more heat needs disipating, ever heard of a solar wax melter hmmm

seen what happens to wax inside it possibly....

The bees know what they're doing even if you dont

 

[Graham40]

Quite not so...


It better get over 20 degrees I want some clover lol

 

[John M]

Quite not so...

.And you hives are over heating? How often this summer your temps have went over 20C?

I ahve used 10 years electrict heating on the bottom of all hives. It teaches how importnat is temperature to the hive, even to 4 box hive. It helps to make bigged broo ball radius.

Lets think that radius is 15 cm. Then it expands to 20 cm. Radius is 30% more. How much more is the ball volume.

radius 15 cm ---> ball volume 14 100
radius 20 cm ---> ball volume 33 500

the volume is 2.4 fold

.

The surface area of the ball will have increased by a factor of (4/3)^2 = 16/9 or a little less than 80% extra (1.8 fold increase), and the volume has increased by (4/3)^3 = 64/27 or about 140% extra (2.4 fold increase).

This pay off between a square and cube rule shows how much more energy efficient a larger cluster can be (volume linked to how many bees and surface area linked to the rate of heat loss).

Just my quick attempt at the maths. I know it will be more complicated than this but it agrees with Finman's general case.

 

[Finman]

This pay off between a square and cube rule shows how much more energy efficient a larger cluster can be .

yes, that is the big issue. Energy loss.

Small colonies are often in trouple to maintain their cluster heat. They must eat much and their gut is full of poor. They make desperate flight to cold air and cannot return. It is like nosema case but caused by cold.

 

[Finman]

Quite not so...


It better get over 20 degrees I want some clover lol

Big Lol there. We have here 30 C and alsike clover and white clover in bloom.

Farmers have now red clover + alsike clover mixture, and alsike give food to bees nicely. Red clover gives nothing.

Last night we had 22 C.

 

[OXFORDBEE]

yes, that is the big issue. Energy loss.
Small colonies are often in trouple to maintain their cluster heat. They must eat much and their gut is full of poor. They make desperate flight to cold air and cannot return. It is like nosema case but caused by cold.

Don't forget the chalk brood..

 

[user 6228]

Hi,
If bees try and keep brood at around 93F then surely adding an empty super above them creates heat loss?
Wouldn't it be better to add a crown board first, and if not using excluders perhaps discourage spread of brood to supers?

It doesnt create any extra heatloss from the hive it just moves the heat up into the super.. There is naturally a temperature gradient from the top to the bottom. After adding the super, the hotter space that was in the top of the brood box is now in the top of the super. To restore the temperature in the brood box the bees need to raise heat output and/or cover the brood.
crown boards that are thin plywood are of no significant thermal consequence as their conductance is high.

 

[user 6228]

Quite not so...

.And you hives are over heating? How often this summer your temps have went over 20C?

I ahve used 10 years electrict heating on the bottom of all hives. It teaches how importnat is temperature to the hive, even to 4 box hive. It helps to make bigged broo ball radius.

Lets think that radius is 15 cm. Then it expands to 20 cm. Radius is 30% more. How much more is the ball volume.

radius 15 cm ---> ball volume 14 100
radius 20 cm ---> ball volume 33 500

the volume is 2.4 fold

.

Using a sphere for temperature modelling is a very crude approximation, as the box is full of air and not a solid. A better model is to think of it as a set of thin boxes at a set temperature one above the other each box with potentially differing thermal conductances on each side with a set of vertical plate heaters. The higher temperatures in the higher boxes mean the thermal conductances to the outside world on the top surface and the sides near the top predominate.

 

[user 6228]

Firstly, as derekm will surely be along to point out soon, any extra effort the bees expend in heating (or cooling) is reflected in a reduction in the honey crop.
They will use more 'fuel' so there will be a smaller surplus (or the beekeeper will have to provide {even} more sugar).
Insulation reduces heat loss all the time that the outside temperature is below about 33C, making for an increased crop.

Secondly, I'm sure the temperature in Aberdeen does get above 33C.
But not often enough to worry about.

Energy loss affects everything , from build up to honey ripening, as well as the nectar volume that endsup as honey.

Remember honey ripening is energy intensive and that has to come from collected sugars.
Fetching pollen takes energy
growing bees need food (energy) and heat (energy). If you let the energy leak away then it cant become bees
and if it cant become bees then you have lost the energy gathering capacity as well.
so the honey impact is much larger than just the energy lost.

 

[Finman]

Don't forget the chalk brood..

i have breeded chalkbrood away from my bee stock. If I see it, I surely remember. i amnot so old.

.but why I should remember just chalkbrood?

 

[Finman]

Using a sphere for temperature modelling is a very crude approximation, as the box is full of air and not a solid.

oh dear! Where we need modelling?
Who needs it?

Even a bee is mostly air.

Its weight is 0,120 g but it size is like 1 g berry.

.but this has nothing to with question, what is right time to give a super that bees not suffer for vain space.

 

[user 6228]

oh dear! Where we need modelling?
Who needs it?

Even a bee is mostly air.

Its weight is 0,120 g but it size is like 1 g berry.

.but this has nothing to with question, what is right time to give a super that bees not suffer for vain space.

you were doing the modelling using crude methods... another Finman logical fallacy attributing the opponent with your own behaviour then saying its invalid.