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Fusion_power said:
Derek, your post ignores the bees ability to raise their output of heat to deal with lower temperatures. IOW, your post suggests the amount of heat generated is fixed. My experience is that the bees increase heat generated while clustering tighter to reduce the surface area of the cluster reducing the escape of heat from the cluster. The combination of generating more while letting less escape is very much what I describe as heating the cluster, not the hive.
Click to expand...

My post doesnt ignore their ability to increase it refers to going downwards. Honey bees can go up to 300W/Kg go read the reference I gave..

Your experience is erroneous or you are confusing heat (thermal energy (Joules) or thermal energy per unit time (Watts) ) with temperature ( measured in Kelvins or centigrade)
So I will make it clear

If you input more thermal energy per second(W) and keep the thermal conductance(W/K) the same, the temperature difference(K) goes up.

If you decrease the thermal conductance(W/K) and keep the energy(W) the same the temperature difference(K) increases.

Therefore, if honey bees decrease their thermal conductance(W/K) and keep the same temperature difference, between the inside and outside of the cluster, they then need to reduce their thermal energy per second(W) output.

A honey bee colony can change both the rate of energy output(W) and its thermal conductance(W/K). However in the steady state thermal energy leaks out of a cluster at the minimum rate of 5W/kg according to experimental research of honey bees referenced above.

If we have 2kg of bees they leak a minimum 10W. In equilibrium 10W and a hive of 2.5W/K means a minimum temperature difference of 4K (or centigrade) across the walls of the hive. It doesn't need another experiment to prove it that been done already. thermal energy leaking from honey bee clusters is no different to thermal energy from any thing.
 
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derekm said:
My post doesnt ignore their ability to increase it refers to going downwards. Honey bees can go up to 300W/Kg go read the reference I gave..

Your experience is erroneous or you are confusing heat (thermal energy (Joules) or thermal energy per unit time (Watts) ) with temperature ( measured in Kelvins or centigrade)
So I will make it clear

If you input more thermal energy per second(W) and keep the thermal conductance(W/K) the same, the temperature difference(K) goes up.

If you decrease the thermal conductance(W/K) and keep the energy(W) the same the temperature difference(K) increases.

Therefore, if honey bees decrease their thermal conductance(W/K) and keep the same temperature difference, between the inside and outside of the cluster, they then need to reduce their thermal energy per second(W) output.

A honey bee colony can change both the rate of energy output(W) and its thermal conductance(W/K). However in the steady state thermal energy leaks out of a cluster at the minimum rate of 5W/kg according to experimental research of honey bees referenced above.

If we have 2kg of bees they leak a minimum 10W. In equilibrium 10W and a hive of 2.5W/K means a minimum temperature difference of 4K (or centigrade) across the walls of the hive. It doesn't need another experiment to prove it that been done already. thermal energy leaking from honey bee clusters is no different to thermal energy from any thing.
Click to expand...

Blimey! :winner1st:
 
derekm said:
My post doesnt ignore their ability to increase it refers to going downwards. Honey bees can go up to 300W/Kg go read the reference I gave..

Your experience is erroneous or you are confusing heat (thermal energy (Joules) or thermal energy per unit time (Watts) ) with temperature ( measured in Kelvins or centigrade)
So I will make it clear

If you input more thermal energy per second(W) and keep the thermal conductance(W/K) the same, the temperature difference(K) goes up.

If you decrease the thermal conductance(W/K) and keep the energy(W) the same the temperature difference(K) increases.

Therefore, if honey bees decrease their thermal conductance(W/K) and keep the same temperature difference, between the inside and outside of the cluster, they then need to reduce their thermal energy per second(W) output.

A honey bee colony can change both the rate of energy output(W) and its thermal conductance(W/K). However in the steady state thermal energy leaks out of a cluster at the minimum rate of 5W/kg according to experimental research of honey bees referenced above.

If we have 2kg of bees they leak a minimum 10W. In equilibrium 10W and a hive of 2.5W/K means a minimum temperature difference of 4K (or centigrade) across the walls of the hive. It doesn't need another experiment to prove it that been done already. thermal energy leaking from honey bee clusters is no different to thermal energy from any thing.
Click to expand...


So all I need is to convert their energy to electricity and I can light our house for free
:paparazzi:
 
Looking at some of the conditions endured by honey bees, I can't help thinking they were not seeking out Tropical conditions.
Creatures do some strange things, Emperor Penguin boys go and stand in a huddle in the coldest place on Earth. Where's the sense in that? I'm not a Penguin so I'll never know.
I've seen too many examples of bees thriving in so called inadequate structures, natural or manufactured, to worry about how they do it or why. Far more important to any colony's ability to survive the Winter is the overall health and sufficient stores. I've mentioned a friend of mine who uses no insulation and both porter holes open, he rarely loses a colony and he rarely bothers feeding, preferring to leave them enough of their own.
A colony on seven combs attached to a corrugated, zinc roof of a Dutch barn had sufficient stores to get through Winter. They were removed the following Spring and still had spare, capped honey.
No doubt merely anecdotal but there you go.
 
Swarm said:
Looking at some of the conditions endured by honey bees, I can't help thinking they were not seeking out Tropical conditions.
Creatures do some strange things, Emperor Penguin boys go and stand in a huddle in the coldest place on Earth. Where's the sense in that? I'm not a Penguin so I'll never know.
I've seen too many examples of bees thriving in so called inadequate structures, natural or manufactured, to worry about how they do it or why. Far more important to any colony's ability to survive the Winter is the overall health and sufficient stores. I've mentioned a friend of mine who uses no insulation and both porter holes open, he rarely loses a colony and he rarely bothers feeding, preferring to leave them enough of their own.
A colony on seven combs attached to a corrugated, zinc roof of a Dutch barn had sufficient stores to get through Winter. They were removed the following Spring and still had spare, capped honey.
No doubt merely anecdotal but there you go.
Click to expand...

A tree, before they have warmed it up, is inhospitable as its thermal capacity is huge although its thermal conductance is low. This ability, to survive the warming up stage of living in the tree, is probably what you are seeing in these inadequate structures.
This thermal capacity means, while they suffer poor survival rates for new colonies, established ones have very, very, good survival rates.
Humans experience the same when moving into a very thick walled stone cottage that hasn't been lived for a while. Takes forever and a lot of fuel to get warm but is easily kept warm.
The penguins? That coldest place on Earth has the best fishing or it used to.
 
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This thermal capacity means, while they suffer poor survival rates for new colonies
Click to expand...
Poor survival for newly established colonies usually comes down to age of queen and amount of stores. The old queen usually leaves with the primary swarm. If she is not replaced before winter, there may not be enough bees to cluster and keep warm. If she is replaced, the new queen may not have enough time to lay eggs to prepare for winter and/or they may not collect enough honey on the fall flow to make it. The primary differentiating factor in survival of a 2 year colony vs a 1 year swarm is the amount of stores in the 2 year colony.

I can recall several open air colonies seen over the years that wintered just fine because they had an abundance of stored honey. The only barrier between the bees and the open air was the comb they had built. This does not take away from or add to the discussion about thermal efficiency of a hive. It just means the bees are capable of keeping themselves warm even in very adverse conditions.

Nobody in their right mind argues that heat does not escape the cluster or that it does not escape from the hive. The discussion is whether or not the bees actively heat the cluster? or actively heat the hive they are in? I submit that the bees maintain relatively even temperatures inside the cluster and do not actively heat the hive itself except as a result of waste heat. Otherwise, how do you explain an open air colony that survives winter?

There is an entirely different discussion that could and should be held about the effect of a better insulating hive on survival of the bees. The hive has to be looked at as a system with a great deal more complexity than just the insulating effectiveness of the hive they live in.

1. What effect does a highly insulated hive have on water production during winter?
2. Does the reduced stress of living in a highly insulated hive have a net negative or net positive effect on winter survival?
3. How does the size of the cluster interact with the benefits and disadvantages of living in a highly insulated hive?
4. Does moisture accumulation in a highly insulated hive detrimentally affect survival?
5. What are the effects of a highly insulated hive in a very windy environment vs a wooden hive?
6. How much does climate interact with the + & - of a highly insulated hive?
7. Does the insulation cause bees to remain quiescent even on warm days when they could have had a cleansing flight?

If you moved to my climate and kept bees the way you do where you live, a large number of colonies would die each winter for no reason except that the beekeeper did not adapt to a different climate. Here it is critical to ensure moisture can escape from a wintering colony. The difference is literally the life or death of the colony. For similar reasons, I'm sure that if I moved to your climate I would lose colonies unless I adapted to different conditions.
 
Fusion_power said:
Poor survival for newly established colonies usually comes down to age of queen and amount of stores. The old queen usually leaves with the primary swarm. If she is not replaced before winter, there may not be enough bees to cluster and keep warm. If she is replaced, the new queen may not have enough time to lay eggs to prepare for winter and/or they may not collect enough honey on the fall flow to make it. The primary differentiating factor in survival of a 2 year colony vs a 1 year swarm is the amount of stores in the 2 year colony.

I can recall several open air colonies seen over the years that wintered just fine because they had an abundance of stored honey. The only barrier between the bees and the open air was the comb they had built. This does not take away from or add to the discussion about thermal efficiency of a hive. It just means the bees are capable of keeping themselves warm even in very adverse conditions.

Nobody in their right mind argues that heat does not escape the cluster or that it does not escape from the hive. The discussion is whether or not the bees actively heat the cluster? or actively heat the hive they are in? I submit that the bees maintain relatively even temperatures inside the cluster and do not actively heat the hive itself except as a result of waste heat. Otherwise, how do you explain an open air colony that survives winter?

There is an entirely different discussion that could and should be held about the effect of a better insulating hive on survival of the bees. The hive has to be looked at as a system with a great deal more complexity than just the insulating effectiveness of the hive they live in.

1. What effect does a highly insulated hive have on water production during winter?
2. Does the reduced stress of living in a highly insulated hive have a net negative or net positive effect on winter survival?
3. How does the size of the cluster interact with the benefits and disadvantages of living in a highly insulated hive?
4. Does moisture accumulation in a highly insulated hive detrimentally affect survival?
5. What are the effects of a highly insulated hive in a very windy environment vs a wooden hive?
6. How much does climate interact with the + & - of a highly insulated hive?
7. Does the insulation cause bees to remain quiescent even on warm days when they could have had a cleansing flight?

If you moved to my climate and kept bees the way you do where you live, a large number of colonies would die each winter for no reason except that the beekeeper did not adapt to a different climate. Here it is critical to ensure moisture can escape from a wintering colony. The difference is literally the life or death of the colony. For similar reasons, I'm sure that if I moved to your climate I would lose colonies unless I adapted to different conditions.
Click to expand...
Heat transfer , fluid flow, state change (Evaporation, condensation) and metabolism/combustion are all interconnected thats why there is a single scientific discipline to cover them called THERMOFLUIDS
My talk at Apimondia 2019 in Montreal was the "Thermofluid analysis of the extended phenotype of a honey bee colony" attached. Read of some the papers to get a longer answer.

Derek Member PGR researcher in the Institute of THERMOFLUIDS, School of Mechanical Engineering, University of Leeds.

1. Mitchell D. 2019 Thermal efficiency extends distance and variety for honey bee foragers: Analysis of the energetics of nectar collection and dessication by Apis mellifera. J. R. Soc. Interface 16. (doi:10.1098/rsif.2018.0879)

2. Mitchell D. 2019 Nectar, Humidity, Honey bees (Apis mellifera) and Varroa in summer: A theoretical thermofluid analysis of the fate of water vapour from honey ripening and its implications on the control of Varroa destructor. J. R. Soc. Interface 22 May. (doi:10.1098/rsif.2019.0048)

3. Mitchell D. 2016 Ratios of colony mass to thermal conductance of tree and man-made nest enclosures of Apis mellifera: implications for survival, clustering, humidity regulation and Varroa destructor. Int. J. Biometeorol. 60, 629–638. (doi:10.1007/s00484-015-1057-z)

4. Mitchell D. 2017 Honey bee engineering: Top ventilation and top entrances. Am. Bee J. 157, 887–889.
 

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Picture taken today at the back ( no sun at any time of day)! Of a 14x12 with a nadired super
Entrance is on the left at the front ( right at on this view)
Bees flying and bringing in ivy
 

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derekm said:
there was a company at Apimondia flogging s/w to interpret photos like that one
Click to expand...

I think FLIR do that for you. I can see how some might want to really get their teeth into the physics of this but for me it’s a little fun ( stupidly expensive camera for a bit of fun but you know how hobbies can run away with you :D)
I can see where the bees are and that the box they are in is hotter on the outside than ambient.
The heat signature is much more dramatic in winter when it’s cold, of course. Their feeder is off and they now have a cosy so I won’t see them till spring.
 
Erichalfbee said:
I think FLIR do that for you. I can see how some might want to really get their teeth into the physics of this but for me it’s a little fun ( stupidly expensive camera for a bit of fun but you know how hobbies can run away with you :D)
I can see where the bees are and that the box they are in is hotter on the outside than ambient.
The heat signature is much more dramatic in winter when it’s cold, of course. Their feeder is off and they now have a cosy so I won’t see them till spring.
Click to expand...

This is the company https://www.thebeecorp.com/verifli.html

this the abstract of their talk
Pollination Hive Grading Using Infrared Image Analysis
E. Symes, W. Wells, G. Riggs, G. Alexeev
The Bee Corp., Bloomington, USA
The Bee Corp (TBC) received a Small Business Innovation Research (SBIR) Grant from the National Science Foundation (NSF) to research
and develop a beehive grading solution for commercial pollination. TBC’s Phase I research proved the viability of infrared (IR) image analysis
to determine hive population from a commercial and a technical feasibility perspective. Modeling hive population from IR images included
image processing and segmenting, statistical modeling, feature engineering, model optimization, and performance testing. To build these
models, ambient, biological, and thermodynamic factors were included to account for heat effects on the IR image not caused by the bees.
TBC then built an image recognition model to find the hive in each image in order to automatically extract thermal values for analysis.
During Phase I, TBC proved the technology is viable and IR data can be used to accurately calculate colony size. TBC also demonstrated
market demand and commercial viability for the solution. Through these pilot tests, TBC determined necessary improvements for its NSF
SBIR Phase II grant application for full commercial scalability and viability.
 
Derek, On slide 9 of 26, "Or conversely we need to remove top vents when we add significant insulation" does not have supporting data to show why this is important. Why is it important to remove top vents? What dynamic changes so abruptly in a highly insulated hive as compared to a hive with no insulation? What is being conserved by removal of top vents?

I also do not see discussion of the changes in hive behavior during winter when they can't forage for water. How does this change in a highly insulated hive vs wooden?
 
Fusion_power said:
Derek, On slide 9 of 26, "Or conversely we need to remove top vents when we add significant insulation" does not have supporting data to show why this is important. Why is it important to remove top vents? What dynamic changes so abruptly in a highly insulated hive as compared to a hive with no insulation? What is being conserved by removal of top vents?

I also do not see discussion of the changes in hive behavior during winter when they can't forage for water. How does this change in a highly insulated hive vs wooden?
Click to expand...
Read the reference : I got 13 minutes at Apimondia... 2 minutes for questions.
Mitchell, D. (2017). Honey bee engineering: Top ventilation and top entrances. American Bee Journal, 157(8), 887–889.
which is a simplification and the honey bee context of :
Lane-Serff, G. F., Sandbach, S. D., El Khoury, G. K., Andersson, H. I., Pettersen, B., Tammisola, O., … Marsden, O. (2012). Emptying non-adiabatic filling boxes: the effects of heat transfers on the fluid dynamics of natural ventilation. Journal of Fluid Mechanics, 701(2012), 386–406. https://doi.org/10.1017/jfm.2012.164

In the ABJ I understated the energy losses from top vents. As you also have to allow for lost energy in the water vapour that is not condensed inside the domain of the nest
 
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