I had made some insulation blankets for my hives when the temps got into the single digits earlier this winter. We just don't see single digits here typically. So being a 1st year beek I wanted to ere on the side of caution. Well a few weeks ago I took them off so I could inspect and left them off. Now we are suppose to get 6-12" snow. Temps are suppose to only get to high 20's. In my most productive hive I have a deep that has capped brood in at least 7 of the frames with lots of bees. Shuold I go put my blankets back on so the brood on the outside frames is not chilled?
ramdino
Go with your gut instinct, I would put the blankets back on at least till the cold front has passed.
Could you provine a picture or description of your insulation blanket and how you use it on the hives? I will be insulating my hives in future winters to protect against these extreme temperature swings so the search is on for some type of home spun design that is not too costly......Thanks
Could you provine a picture or description of your insulation blanket and how you use it on the hives? I will be insulating my hives in future winters to protect against these extreme temperature swings so the search is on for some type of home spun design that is not too costly......Thanks
Studies were done many years ago, you can read about them in the ABC XYZ of Bee Culture, that showed insulating does not help keep the inside of the hive warmer. I have insulated hives myself with foamboard, but I feel that it did more good for me (other than costing me more money) than the bees. Don't misunderstand, whether you insulate or just wrap with tar paper, those two things help with cutting down wind penetrations, which I really feel is much more important and should be the goal. A strong cluster can deal with below zero temperatures, but add in strong winds and it makes it much worse, not because of the wind chill, but the wind forces its way through cracks and crevices in the hive and makes it more drafty which in itself is detrimental to the cluster keeping warm.
The tar paper (being black) helps with solar gains. I have personally observed unwrapped hives being stuck inside the hive, whilst the tar paper wrapped ones were able to get out for a cleansing flight. I also tried open screen bottom boards vs solid bottom boards, finding no significant difference. http://honeydrunkapiaries.blogspot.ca/2014/01/overwintering-experiment-winter-2013.html We have been experiencing weather in the -30F range to give you an idea of the extremes.
It is a misconception to say interior temp of an insulated hive is not much above outside ambient.
A heat source(cluster of bees) inside a closed insulated enclosure will raise the internal temp. A significant factor on how much inside temp increases is how much ventilation is going on. If there is a large flow of air, ambient temp will not increase appreciably
If both bottom and top entrances are reduced to minimal size to reduce ventilation to a minimum yet adequate internal temp rises significantly. Temp rise varies significantly from next to outside wall to just above cluster.
From my experience with two side 1/2 by 3/8 inch bottom entrances, the temp above the inner cover is 20-30F warmer than outside ambient.
A heat source(cluster of bees) inside a closed insulated enclosure will raise the internal temp. A significant factor on how much inside temp increases is how much ventilation is going on. If there is a large flow of air, ambient temp will not increase appreciably
If both bottom and top entrances are reduced to minimal size to reduce ventilation to a minimum yet adequate internal temp rises significantly. Temp rise varies significantly from next to outside wall to just above cluster.
From my experience with two side 1/2 by 3/8 inch bottom entrances, the temp above the inner cover is 20-30F warmer than outside ambient.
The studies that I referred to, used at least 118 temperature sensors located throughout each two story hive in the study, these were double walled hives with extreme degrees of insulation.
They found that even in these highly insulated hives in a protracted cold spell, the air temperatures in the hives were all at ambient except right at the very edge of the cluster where the temperature was around between 43 and 46 degrees. That proves that the bees don't heat the hive, only their cluster.
Now, if you wrap your hive with tar paper, on a sunny day the paper will absorb heat and transfer it to the walls of the hive, which in turn probably heats up the interior of the hive above ambient. That is different than saying the bees heat up the hive above ambient and the insulation conserves that heat.
They found that even in these highly insulated hives in a protracted cold spell, the air temperatures in the hives were all at ambient except right at the very edge of the cluster where the temperature was around between 43 and 46 degrees. That proves that the bees don't heat the hive, only their cluster.
Now, if you wrap your hive with tar paper, on a sunny day the paper will absorb heat and transfer it to the walls of the hive, which in turn probably heats up the interior of the hive above ambient. That is different than saying the bees heat up the hive above ambient and the insulation conserves that heat.
What was the size of the bottom entrance and top entrances? Amount of ventilation is a very significant factor. If there is lots of ventilation, then internal temp will not increase much over outside ambient.
As an analogy, run a furnace in an insulated house and open the doors and what would inside temp be?
Temp above my inner cover is 20-30F warmer than ambient.
As an analogy, run a furnace in an insulated house and open the doors and what would inside temp be?
Temp above my inner cover is 20-30F warmer than ambient.
They did not say an exact measurement, only that they were using greatly reduced hive entrances. No mention of whether top entrances were used. They also said that a benefit of using insulation is that it retards the rate of temperature change within the unoccupied hive space, helps it cool down more slowly with sudden outside drop in temperature, allowing the cluster to contract slower. On the other hand, insulation can slow the transfer of warmth from the outside to the inside when outside temperatures are rising quickly, this can hurt because the bees may not benefit from being able to take a quick cleansing flight.
>The bees heat the cluster not the hive.....
I spent a good portion of my life outdoors in a very harsh climate. I guarantee that small things make a huge difference in how cold you are. I have put plywood up in a metal building and you could feel the difference in how much warmer it was and this is a three sided building with the front open. I doubt a thermometer would show much difference, but my ears, nose, fingers and body could sure tell the difference that 3/4" of wood made on only three sides of a three sided building with the front still open to the air. The tempearture in my living room stays the same whether you leave the back door open or not... but it takes a lot more heat...
I spent a good portion of my life outdoors in a very harsh climate. I guarantee that small things make a huge difference in how cold you are. I have put plywood up in a metal building and you could feel the difference in how much warmer it was and this is a three sided building with the front open. I doubt a thermometer would show much difference, but my ears, nose, fingers and body could sure tell the difference that 3/4" of wood made on only three sides of a three sided building with the front still open to the air. The tempearture in my living room stays the same whether you leave the back door open or not... but it takes a lot more heat...
LAndrus, the studies have already been done which show that the small amount of heat that a cluster creates does not add to the warmth of the whole hive. When their warm moist air hits the colder roof and walls it condenses, but good ventilation will carry away most of that moisture so that it doesn't become a problem. People keep trying to compare the inside of an insulated hive in winter to our insulated homes in winter, it simply doesn't work the same, I know that I have a hard time comprehending it also, I guess that's why I keep insulating hives every year.
While it is not the bees' intent,* heat does leak from the cluster and can heat the interior of the hive. In the case of a strong hive, this heat leakage can warm the hive interior by as much as 80F above the ambient air temps:
http://www.beesource.com/forums/showthread.php?291469-Winter-time-fun&highlight=winter+time+fun
I have a bunch more data that I have collected to enter. The general trend is pretty much the same for all the hives, so far.
*"intent" is used tongue-in-cheek, since insects can't form an "intent" as the word is commonly used
http://www.beesource.com/forums/showthread.php?291469-Winter-time-fun&highlight=winter+time+fun
I have a bunch more data that I have collected to enter. The general trend is pretty much the same for all the hives, so far.
*"intent" is used tongue-in-cheek, since insects can't form an "intent" as the word is commonly used
I'm looking forward to getting my hives up and running and using my thermal imager on them. When they've deliberately warmed their flight muscles up (necessary for foraging) they can be as warm as we are. Attached is a thermal image I made last year of an individual forager on a bloom. The hot spot is the thorax, and it is unambiguously warmer that the environment or even the rest of the bee.
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Shinbone, 80F seems like a lot and I would think the probe is next to or within the cluster at 80F rise.
What size is the opening in your bottom entrance? Doesn't look like much more than 1/2 wide by?3/4 high. But minimal and corraborates my point about interior temp and how much ventilation is occurring. Ventialtion is greatly reduced but adequate.
Do you have shavings in the top vent box? I added a screen to the bottom of my vent boxes and layed a piece of burlap on top of the screen and filled with shavings. An area bee keeper was telling me that he wintered 15 out of 15 hives last winter(long and cold winter), and the only significant difference in winter preparation was that he used vented quilt boxes. Two of my four hives had died out.
What size is the opening in your bottom entrance? Doesn't look like much more than 1/2 wide by?3/4 high. But minimal and corraborates my point about interior temp and how much ventilation is occurring. Ventialtion is greatly reduced but adequate.
Do you have shavings in the top vent box? I added a screen to the bottom of my vent boxes and layed a piece of burlap on top of the screen and filled with shavings. An area bee keeper was telling me that he wintered 15 out of 15 hives last winter(long and cold winter), and the only significant difference in winter preparation was that he used vented quilt boxes. Two of my four hives had died out.
All of my hives have interior temps above ambient temps, although there is substantial variation on just how high above ambient each hive is. The 80F example is the highest I have seen and that hive is always close to 80F, irregardless of the ambient air temps. The lowest is about 5F above ambient, and varies substantially with the ambient temps.
While one can argue that the high temps (or any of the above-ambient temps, for that matter) are due to the cluster having enveloped the sensor, that can't always be true because the cluster would eventually exhaust the honey resources in that area and would then move to another region hive and no longer be close to the sensor. In other words, the "close cluster" argument is only a temporary explanation, and one finally has to conclude that the bees are indeed heating the interior of the hive.
1/2" x 1/2" is a good approximation of the bottom entrances. Typical upper entrances vary from 1/2" x 1/2" to 3" x 1/2".
The tops are the Honey Run Apiaries All Season Inner Covers with a piece of foam insulation in place:
http://www.honeyrunapiaries.com/store/all-season-inner-cover-p-232.html
While one can argue that the high temps (or any of the above-ambient temps, for that matter) are due to the cluster having enveloped the sensor, that can't always be true because the cluster would eventually exhaust the honey resources in that area and would then move to another region hive and no longer be close to the sensor. In other words, the "close cluster" argument is only a temporary explanation, and one finally has to conclude that the bees are indeed heating the interior of the hive.
1/2" x 1/2" is a good approximation of the bottom entrances. Typical upper entrances vary from 1/2" x 1/2" to 3" x 1/2".
The tops are the Honey Run Apiaries All Season Inner Covers with a piece of foam insulation in place:
http://www.honeyrunapiaries.com/store/all-season-inner-cover-p-232.html
The thermodynamics of a bee hive are much more complicated that just measuring the temperature of the cluster and the temperature of the hive.
http://www.bushfarms.com/beesscientificstudies.htm#overwintering
http://www.bushfarms.com/beesscientificstudies.htm#overwintering
Michael - So true!
The thermodynamics of a living entity are hugely complicated. My simple little measurements only serve to show the bees do heat the interior of the hive. My only intent with my measurements was to be able know when a hive died out over the winter by showing when a hive interior had cooled down to ambient temps.
The thermodynamics of a living entity are hugely complicated. My simple little measurements only serve to show the bees do heat the interior of the hive. My only intent with my measurements was to be able know when a hive died out over the winter by showing when a hive interior had cooled down to ambient temps.
Here is a post I wrote about how I insulate and wrap my hives. I was please with the results this year.
http://sidelinebeekeeping.com/2013/11/13/wrapping-hives/
http://sidelinebeekeeping.com/2013/11/13/wrapping-hives/
Also, I am in the camp that thermal insulation (as opposed to wrapping a hive to seal out wind) does little if anything to help a hive survive cold temps in most locations.
As long as the hive is healthy and of reasonable size, and is in well maintained equipment, they will survive the winter unless they go off their winter stores. If they lose contact with their food, no amount of insulation will save them.
You'd have to go pretty far north or south before insulation becomes worthwhile.
Just the opinion of a newbie.
As long as the hive is healthy and of reasonable size, and is in well maintained equipment, they will survive the winter unless they go off their winter stores. If they lose contact with their food, no amount of insulation will save them.
You'd have to go pretty far north or south before insulation becomes worthwhile.
Just the opinion of a newbie.
shinbone, I have gone through most of your posts of your temperature readings, but I didn't see you mention what time of day you did the bulk of the readings (except a reference to readings taken one morning), I don't know if they were all taken about the same time of day on the days you did them or not. My questioning this is because when taking temperature readings during the daylight hours you are bound to get higher readings inside than ambient due to solar gain. Did you take any readings well after dusk or well before sunrise, those would be the more accurate readings as to whether or not the bees contribute heating to the whole of the hive? Maybe I just overlooked your reference to time of day as I was quickly scanning through your posts.
jmgi - About half the readings were taken in the dark before sunrise (as I left the house for work), and about half the readings were taken in the early evening at dusk (when I came home from work).
My guess is that in the wintertime for hive box of a light natural pine color (which most of mine are), there is little solar gain. I also should note, that I see little difference between the hives that are wrapped in black insulation (Colony Quilt) and the hives that are unwrapped.
Although I may still set something up this year, next year I will set up an empty hive with a sensor in it to measure solar gain.
My guess is that in the wintertime for hive box of a light natural pine color (which most of mine are), there is little solar gain. I also should note, that I see little difference between the hives that are wrapped in black insulation (Colony Quilt) and the hives that are unwrapped.
Although I may still set something up this year, next year I will set up an empty hive with a sensor in it to measure solar gain.
shinbone, based on your observations then, it would seem to contradict the findings in the study I was referring to in the ABC and XYZ of Bee Culture, that being the cluster and immediately next to it were the only temperature probe readings that were much above ambient in the whole hive. That study appears to me on the surface to have been well done (massachusetts state college) and the results thoroughly recorded using over 118 sensors in a two story hive, so I don't know what the reason would be for their results to not be in line with your simpler experiment, you seem to have done a good job yourself with your small study. Either there is some solar heat gain or heat loss not being factored in somewhere with either experiment, or the bees themselves contribute more to hive heating than most think.
I know it is all words ... gotta admit, that's what you two have been doing.
It would appear that nobody has actually done this sort of testing definitively and, considering I've been gearing up to do this sort of tests on the solar cabin where our hives are going in, I guess I must be the guy who gets to do it. Frankly, I'm amazed that this has not been done. And given my personality, there is no way I'll go to this effort without sharing.
And after posting my ideas, I read Mr. Bush's. I think he's pretty much got it, just somebody needs to prove it.
I would be willing to bet that nobody else here has the head start on equipment ($2700 data acquisition system, $2000 thermal imager, career in instrumentation and testing, and newly-discovered way to make $5 heat flow sensors instead of $280 heat flow sensors). A few have hive scales, but not too many outside of universities can log weight continuously.
Indulge me. I won't have bees until mid April, and then I won't have winter until next winter.
The easiest way to debunk the idea that it is solar gain will be fairly simple. Peltier effect cooling devices are thermopiles, and will generate voltage proportional to heat flow. I've calibrated a handful, but they don't even need calibration to prove or disprove this point. Just stick them on the hive roof and sides. If more heat is going out than in, averaged over a cold sunny day and night, well, there's that possibility gone.
It would appear that nobody has actually done this sort of testing definitively and, considering I've been gearing up to do this sort of tests on the solar cabin where our hives are going in, I guess I must be the guy who gets to do it. Frankly, I'm amazed that this has not been done. And given my personality, there is no way I'll go to this effort without sharing.
And after posting my ideas, I read Mr. Bush's. I think he's pretty much got it, just somebody needs to prove it.
I would be willing to bet that nobody else here has the head start on equipment ($2700 data acquisition system, $2000 thermal imager, career in instrumentation and testing, and newly-discovered way to make $5 heat flow sensors instead of $280 heat flow sensors). A few have hive scales, but not too many outside of universities can log weight continuously.
Indulge me. I won't have bees until mid April, and then I won't have winter until next winter.
The easiest way to debunk the idea that it is solar gain will be fairly simple. Peltier effect cooling devices are thermopiles, and will generate voltage proportional to heat flow. I've calibrated a handful, but they don't even need calibration to prove or disprove this point. Just stick them on the hive roof and sides. If more heat is going out than in, averaged over a cold sunny day and night, well, there's that possibility gone.
This thread has got me all curious. In the next few weeks, I will see if I can set up a simple way to measure solar gain.
Got a digital voltmeter? Got enough patience to take a bunch of readings, day and night?
One of these will put out a bit over 0.1 volts in full sunlight with a heat sink on the back (I'll make a couple of these into proper pyranometers). That's the highest solar input you would see. So stick a few of these in the walls and top of the hives, and measure heat flow in and out. They respond with the same sensitivity either way. I'd bet a healthy hive flows more heat out than in, averaged over the day. Of course, after this winter, they may be nearly out of fuel. Quite a few have starved.
http://www.mpja.com/Thermoelectric-Cooling-Module-127-couple-12VDC/productinfo/30207 PM/
That's the other proof, of course. If the bees are dead, likely the hives will be considerably cooler than healthy hives, but we don't wanna go there. If you have extra hive components you might build a dead hive.
One of these will put out a bit over 0.1 volts in full sunlight with a heat sink on the back (I'll make a couple of these into proper pyranometers). That's the highest solar input you would see. So stick a few of these in the walls and top of the hives, and measure heat flow in and out. They respond with the same sensitivity either way. I'd bet a healthy hive flows more heat out than in, averaged over the day. Of course, after this winter, they may be nearly out of fuel. Quite a few have starved.
http://www.mpja.com/Thermoelectric-Cooling-Module-127-couple-12VDC/productinfo/30207 PM/
That's the other proof, of course. If the bees are dead, likely the hives will be considerably cooler than healthy hives, but we don't wanna go there. If you have extra hive components you might build a dead hive.
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