Bees Only Heat the Cluster, Not the Hive? - Page 5
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  1. #81
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    Default Re: Bees Only Heat the Cluster, Not the Hive?

    Quote Originally Posted by Ian View Post
    I am not quite following you. Please elaborate.

    I <Snip>

    think most of the variations on prepping for winter is simply beekeepers recognizing all the factors, and controlling them which best suits their environment..
    What I am getting at is how did the apparent myth come about that the cluster stays warm independantly of the hive so any insulating is a waste of time; a la, "they only heat the cluster not the hive". I am supposing that some people insulated without considering moisture escape, had no increase in survivability, and declared insulation ineffective". Most of beekeeping lore on this continent probably originates from the south.

    I am in the insulation camp as our weather swings down from the north and is not at all like the most of southern ontario. I have seen a solid month when daytime highs never went above 20 below F.
    Frank

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  3. #82
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    Default Re: Bees Only Heat the Cluster, Not the Hive?

    Quote Originally Posted by Acebird View Post
    If the heat loss from the cluster is less than the heat loss of the hive it will not result is a temperature rise in the hive.
    OK, Ace, if the "hive" is at ambient temperature, how can it be possible that there is ANY "heat loss"?


    In order for the "hive" to "lose heat", surely it must be warmer than ambient temperature to begin with!!!



    Graham
    USDA Zone 7A Elevation 1400 ft

  4. #83
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    Default Re: Bees Only Heat the Cluster, Not the Hive?

    I was putting 3/4" plywood inside a tin shed that has three walls. The tin goes below the dirt already so there is no draft to speak of. It was a bitter cold day. As we added sheets of 3/4" plywood the we were noticeably warmer. Everyone working on the project commented on it. I'm quite certain the temperature in the shed did not change much, but our heat loss did. I have experienced similar things hundreds of times building houses when it was -10 F or so. A very noticeable difference that does not seem likely to change the temperature much since it is open to the air. I think all the measurements and such are just misleading.

    The temperature in my house is pretty close to the same with the door open or closed but the furnace runs a lot more and the draft feels pretty cold and the fuel bill goes up... a system where the bees are generating heat and outside air is coming in and the box provides some but not a lot of insulation and the honey provides some thermal flywheel, is much more complicated than you think...
    Michael Bush bushfarms.com/bees.htm "Everything works if you let it." ThePracticalBeekeeper.com 42y 40h 39yTF

  5. #84
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    Default Re: Bees Only Heat the Cluster, Not the Hive?

    The cluster itself does stay warm pretty much independently. Look at the temperatures I think Graham posted the chart of. 3 degrees outside. in the 40's at the least inside the hive. Btu bees are not the only thing that will warm that hive. it setting in the sun will warm it also. SO how much of that temperature difference is outside heat sources. How long will a hive hold that heat once the heat source is removed (the sun goes down).

    The core of the cluster is 90 degrees or more. that is the heat bees generate. That is the cluster keepign itself warm. because 40 degrees is not warm enough for the entire cluster.

    What you really need to look at is what happens right where cluster meets air. What change is seen there. For the most part you see a cluster very warm at the core. slowly cooling to it's outer edges until the surface of the cluster is almost the same temperature of the hive. No heat loss.

    What I see is bees that generate heat at extremely low power output. And then they are very very good at keeping that heat in their cluster. That the hive is warmer than the outside air is no surprise. nearly anything is warmer than outside air.
    Everything gets darker, as it goes to where there is less light. Darrel Tank (5PM drawing instructor)

  6. #85

    Default Re: Bees Only Heat the Cluster, Not the Hive?

    This is a great thread!!!
    Started beekeeping in 2013 and having a blast with my 12 small cell hives!!

  7. #86
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    Default Re: Bees Only Heat the Cluster, Not the Hive?

    If the center of the cluster is ~90F. and the outside of it ~45 that clearly shows heat loss. Barring the existence of a perfect insulator it could be no other way. We can safely assume that the outside of the cluster must not go below 45 F. or the bees lose muscle control and fall to the floor. That puts the outside temp of the cluster at 45f. or higher. Any time the temperature of the air in the hive is lower than this temperature, heat will transfer away by convection. Any time the margin of the frames outside the cluster are below this temperature heat will flow into them by conduction. Any time the hive walls are below this temperature heat from the cluster will be lost via radiation.

    Heat transfer from one body to another, via any of the means, conduction, convection or radiation, is proportional to the temperature differential between the respective bodies.

    Could someone that is current on heat exchange theory explain the significance of the energy in the water vapor and whether more or less of that energy could be affected by our method of conveying it out of the hive. (Analogy; I am in the process of installing a high efficiency gas furnace that condenses the water vapor and recovers the latent heat.) My mind toys with the notion that the shavings quilt on top of the hive might have a small recovery effect compared to just dumping the vapor directly out an opening.
    Frank

  8. #87
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    Default Re: Bees Only Heat the Cluster, Not the Hive?

    Quote Originally Posted by crofter View Post
    If the center of the cluster is ~90F. and the outside of it ~45 that clearly shows heat loss. Barring the existence of a perfect insulator it could be no other way. We can safely assume that the outside of the cluster must not go below 45 F. or the bees lose muscle control and fall to the floor.
    Right about the heat leaving the cluster, this is heat loss or waste heat. The system is not 100% efficient, like heat going up a chimney. On the other hand, some heat has to leak out to the outer bees to keep them above 45 F like you say. However, they don't fall when they die. Most of us have seen a cluster that died, they are all tightly packed together.

    I have a theory that one cause of winter mortality may be that the inner group runs out of honey but the outer shell becomes too cold to move. The whole cluster starves even though there is honey near by,

  9. #88
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    Default Re: Bees Only Heat the Cluster, Not the Hive?

    Peter, I think that when we examine a cluster that has gone into failure mode we may see conditions that we would not if it survived. In terminal stages no doubt the bees that have failed to circulate will be wedged between frames rather than falling to the floor. You may be right that they physically impede the cluster moving onto replacement honey comb. I think that the key is they have exhausted the honey they are on and cannot move to fresh source.

    Yes, heat will flow towards the cluster margins whether on the bodies of the circulating bees or in the air that must be circulated to get rid of the carbon dioxide and bring in oxygen.
    Frank

  10. #89
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    Default Re: Bees Only Heat the Cluster, Not the Hive?

    I still think the factor that many are leaving out is the fact of ventilation.....making sure that warm, moist air is expelled from the hive through a hole near the top of the hive, thus leaving the interior of the hive cold, except for the cluster. Think of it like this, you have a fireplace burning in your living room downstairs but you leave the bedroom windows open so that the smell from the fireplace can escape. How warm is your bedroom likely to be?
    20 hives, 10 years, T and TF, All local stock

  11. #90
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    Default Re: Bees Only Heat the Cluster, Not the Hive?

    Ventilation is a big part of the puzzle. I think there is an optimum amount and both over and under are problems. I think different methods can do the job but some may lose far more heat in the process. Over ventilation certainly will lose heat unnecessarily. If you can condense the moisture to a liguid within the hives heat envelope, then wick it to a point outside the hive to be evaporated by outside air, you could satisfy moisture removal with virtually no air exchange (you still need some air exchange for CO2 and Oxygen exchange though).

    I think a shavings pillow or quilt is more than just insulation!
    Last edited by crofter; 10-22-2014 at 11:47 AM. Reason: Addition
    Frank

  12. #91
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    Default Re: Bees Only Heat the Cluster, Not the Hive?

    Quote Originally Posted by Rader Sidetrack View Post
    In order for the "hive" to "lose heat", surely it must be warmer than ambient temperature to begin with!!!
    How does radiant energy pass through air without raising its temperature?
    Brian Cardinal
    Zone 5a, Practicing non-intervention beekeeping

  13. #92
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    Default Re: Bees Only Heat the Cluster, Not the Hive?

    Quote Originally Posted by Acebird View Post
    How does radiant energy pass through air without raising its temperature?
    Ace, in the context that I was using the word "ambient", it is a reference to the outside temperature, meaning outside the hive.

    My point was that if the hive [body] is to "lose heat", it can only do so if it is warmer than the outside air.



    There is more going on in heat transfer inside a hive that just "radiant energy". See crofter's post #86 for some of the other factors.
    Graham
    USDA Zone 7A Elevation 1400 ft

  14. #93
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    Default Re: Bees Only Heat the Cluster, Not the Hive?

    Quote Originally Posted by Rader Sidetrack View Post
    My point was that if the hive [body] is to "lose heat", it can only do so if it is warmer than the outside air.
    That is completely untrue. A heat pump can take heat from a colder space and move it to a warmer space. The bees do this all the time in the summer by fanning and evaporation of water. Water loses heat at 32 degrees without getting any colder before it freezes it also gains heat without an increase in temperature before it turns to steam. This is just getting technical and offers nothing to the main discussion.

    The people in Canada need to insulate their hives. The people in NC that are not at high elevation do not. The people who are in between these locations may see a benefit for insulation or may not. There are too many variables to make a statement either way that could be proven.
    Brian Cardinal
    Zone 5a, Practicing non-intervention beekeeping

  15. #94
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    Default Re: Bees Only Heat the Cluster, Not the Hive?

    Heat Pump?? Really? Heat Pump??




    What does a heat pump have to do with a hive losing heat to the air outside a bee hive?
    Graham
    USDA Zone 7A Elevation 1400 ft

  16. #95
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    Default Re: Bees Only Heat the Cluster, Not the Hive?

    Ace, you are trying to use the term heat and the term energy interchangeably. In the heat pump analogy you are using an interim refrigerant liquid that must be colder than the source of the heat that flows into it. You can capture energy by making something colder but heat directly will only flow into an object that is colder. To make the system work that you describe needs the imput of an external source like the sun or electricity. Even the bees fanning is an external energy source powered by nectar or honey. The laws of thermodynamics are not subject to modification by Acebird. He is free to misconstrue them but they remain unchanged.

    I think the smart money is on Rader
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  17. #96
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    Default Re: Bees Only Heat the Cluster, Not the Hive?

    Quote Originally Posted by crofter View Post
    Even the bees fanning is an external energy source powered by nectar or honey.
    That is my point heat can flow from cooler to warmer if there is another energy source pushing it. Rader is trying to equate heat to temperature and it is not.

    but heat directly will only flow into an object that is colder.
    And again this statement is wrong. Generally it is true but in the case of water changing state heat is taken on or given up without a change in temperature. I am sure there are other instances where this happens in nature.
    Brian Cardinal
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  18. #97
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    Default Re: Bees Only Heat the Cluster, Not the Hive?

    Quote Originally Posted by Acebird View Post
    That is completely untrue. A heat pump can take heat from a colder space and move it to a warmer space. The bees do this all the time in the summer by fanning and evaporation of water. Water loses heat at 32 degrees without getting any colder before it freezes it also gains heat without an increase in temperature before it turns to steam. This is just getting technical and offers nothing to the main discussion.

    The people in Canada need to insulate their hives. The people in NC that are not at high elevation do not. The people who are in between these locations may see a benefit for insulation or may not. There are too many variables to make a statement either way that could be proven.


    Ace you have introduced gasses pressure and expansion and a bunch of other things that have no application. allow a gas to expand it absorbs heat. move it somewhere else and compress it it gives that heat up. Not applicable to what is happening in a hive.

    It is true that a body warmer body will loose heat to a colder body. only if that heat can move. In what ways are bees in a cluster preventing that movement?
    Everything gets darker, as it goes to where there is less light. Darrel Tank (5PM drawing instructor)

  19. #98
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    Default Re: Bees Only Heat the Cluster, Not the Hive?

    Quote Originally Posted by Acebird View Post
    That is completely untrue. A heat pump can take heat from a colder space and move it to a warmer space. The bees do this all the time in the summer by fanning and evaporation of water. Water loses heat at 32 degrees without getting any colder before it freezes it also gains heat without an increase in temperature before it turns to steam. This is just getting technical and offers nothing to the main discussion.

    The people in Canada need to insulate their hives. The people in NC that are not at high elevation do not. The people who are in between these locations may see a benefit for insulation or may not. There are too many variables to make a statement either way that could be proven.
    A solid that does not experience change of state is not affected by the phenomenon of latent heat of phase change. By radiation to a colder object it is possible for something to be sightly colder than its surrounding air but that also does not apply to conditions that surround a hive. I doubt anyone is concerned about what will happen if you put a bee hive in a tank of water at 32F.

    Get Real!
    Last edited by crofter; 10-23-2014 at 08:33 AM. Reason: add "not"
    Frank

  20. #99
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    Default Re: Bees Only Heat the Cluster, Not the Hive?

    some basic thermodynamics, a fancy name for heat transfer. there is no such thing as cold, cold is less heat. heat [energy] flows from a higher place toward a lower place of heat always. the flow transfer rate depends on insulation. the flow rate depends also on movement of air or liquid over the transfer area. that is why we have wind-chill, more air movement equals faster heat transfer.... when matter changes state a lot of energy is transferred, in bee terms when liquid moisture in the hive is changed to vapor a lot of energy is absorbed by the change liquid to vapor, this energy is absorbed from the surroundings, this is called the refrigeration effect. if bees are wet they get cold [less heat] as they dry out.... so we have a cluster of bees trying to keep the queen alive. as it gets colder the cluster gets tighter, this slows down heat loss. some heat is also always transferred this raises the temperature of the hive some. the bees are not trying to heat the hive they are trying to regulate cluster temperature. hive insulation and/or a windbreak causes slower heat loss. no liquid water [or less] greatly lowers heat loss. the higher the temperature the more moisture air can hold. if you put more moisture ,over the dew point, in the air it rains, if the air is saturated [dew point] and the temperature drops it rains. bees breathe and this moisture is in the air, the air can only hold so much depending on temperature, drops of moisture [or ice] form as the bees contact this they loose heat...the heat transfer and moisture change of state effect are really 2 different things happening at once.... I hope most of you can follow this.
    Last edited by mathesonequip; 10-23-2014 at 07:57 AM.

  21. #100
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    Default Re: Bees Only Heat the Cluster, Not the Hive?

    This might be something that more people have had experience with that is an exampel of what ace is talking about. How many people have actually seen or had a propane bottle freeze on them? I have seen it fairly often when it comes to propane BBQ grills.

    Propane in a bottle is under pressure. this is what keeps it liquid. It is also a liquid that has a very low boiling point. way below freezing. So any time you release that pressure propane boils basically turns to gas (Steam) and will burn. As the pressure in the tank decreases more and more liquid boils. this requires additional heat. Or that absorbing of heat I described earlier. Where is that heat coming from? it is gettign the heat form the metal tank. it is absorbing heat through that metal and when the metal can no longer keep up it will actually freeze. And guess what the gas inside the tank is doing. it is still getting heat right from that ice. You will eventually reach a point there simply is not enough heat available to the liquid and the process will stop. But this is an exampel of how an expanding gas will take heat from something even much much colder than itself. and yes ice has heat in it.
    Everything gets darker, as it goes to where there is less light. Darrel Tank (5PM drawing instructor)

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