# Solar Gain Tests



## shinbone (Jul 5, 2011)

From left to right: shielded; bare natural-wood finish; Colony Quilt; Bee Cozy


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## shinbone (Jul 5, 2011)

From left to right: shielded; bare natural-wood finish; Colony Quilt; Bee Cozy

From top to bottom: 
Wall[SUB]o[/SUB] = outside wall temp; 
Wall[SUB]i[/SUB] = inside wall temp; 
Inter. = interior air temp.


2/27/2014, 0600h - about 45 minutes before sunrise. Ambient air temp 24.5F.











2/27/2014, 1700h - at the end of a partially cloudy day. Ambient air temp 54.4F.











2/27/2014, 1000h - about 2-1/2 hours after sunset. Ambient air temp 45.6


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## bluegrass (Aug 30, 2006)

Now that is my kind of test:thumbsup:

Though the results are difficult to sort through.


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## bluegrass (Aug 30, 2006)

Did you happen to check ambient temp at the time of the reading?


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## cg3 (Jan 16, 2011)

I'm reading it as neglible difference, or am I missing something?


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## shinbone (Jul 5, 2011)

bluegrass - edited to add ambient air info.

Ambient air temp was a few degrees less than the interior air temp of the shielded hive in the second data photo of post #2 because the day was just starting to cool off and the mass of the shielded hive was holding a little bit of warmth. The morning photo shows that at thermal equilibrium, the shielded hive interior is practically the same as ambient air. At least, that is my interpretation of the data shown so far.


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## bluegrass (Aug 30, 2006)

did you calibrate the thermometers off of each other? There could be that much variable just in the temp sensors. I have an indoor weather station that is off by 14 degrees compared to what the local weather beacon reads.


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## dynemd (Aug 27, 2013)

I'm reading the Colony Quilt warmed up in the sun more than the Shielded. Nice Work!


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## shinbone (Jul 5, 2011)

bluegrass - the maximum spread between the thermometers is about 2.5F. Note how close they read to one another just before sunrise when temps have equalized between all the hives.


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## bluegrass (Aug 30, 2006)

dynemd said:


> I'm reading the Colony Quilt warmed up in the sun more than the Shielded. Nice Work!


Keeping in mind that if a cluster was in side a hive that keeps the sun out, it will also keep the warmth from the cluster in.


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## Edymnion (May 30, 2013)

dynemd said:


> I'm reading the Colony Quilt warmed up in the sun more than the Shielded. Nice Work!


Well thats to be expected. The shield is reflective, its actively bouncing warm sunlight away from the hive.

So from what I'm seeing, the colony quilt was the only thing that made any real difference at all.

Makes sense, the bee cozy appears to be stuffed, which means it is insulating the hive from the warming sun as well.

Honestly I'd think at this point you could probably get very similar results to the quilt by simply taping black construction paper to the sides of the hives.


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## Phoebee (Jan 29, 2014)

The type of sensor used in those little digital thermometers is usually remarkably accurate. Scale factor from unit to unit is nearly identical, so they only have to tweak the zero offset. For consistency, it is a good idea to check them in an ice water bath (50/50 ice and water is 32.0 F).

Me, I'd have thrown the $2700 data acquisition system at it, but I'd have to tear into it and add thermocouple connectors to hook that many channels up. Besides, its in the garage right now testing an electronic hive scale.

One look at the setup above, and I know Shinbone is serious!


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## shinbone (Jul 5, 2011)

Phoebee said:


> One look at the setup above, and I know Shinbone is serious!


That is high praise, considering the source, Phoebee!

I added a third data photo to post #2.

Once I confirm my suspicions that the shielded hive will pretty much track the ambient air temp, I will remove the shielding and wrap it in roofing paper.


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## bluegrass (Aug 30, 2006)

shinbone said:


> I will remove the shielding and wrap it in roofing paper.


#15 or #30 ?


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## shinbone (Jul 5, 2011)

bluegrass - I think the roofing paper I have on hand is 15#. Is one preferable over the other for testing?


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## Michael Palmer (Dec 29, 2006)

30# is too thick.


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## Mr.Beeman (May 19, 2012)

Tests like this takes time (and money). Thanks for taking the time shinbone. The results are pretty black and white.
I am so looking forward to the tar paper test. 15# is preferred. Just make sure it is wrapped tight so it is in contact with the hive as much as possible. Be ready to be amazed at the results.


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## shinbone (Jul 5, 2011)

Glad to provide some info to folks.

I already know what to expect with roofing paper based on how the Colony Quilt and Bee Cozy have performed. From the CQ and the BC:

The more insulation the black wrapping has, the smaller the temp spike caused by the Sun's heating, and the slower the change of internal temp in the hive, in other words smaller but more gradually changing temps going up and coming down.

The less insulation the black wrapping has, the higher the temp spike caused by the Sun's heating, and the faster the temp changes as the sun cycles through the day and night.

Regardless of the amount of insulation, the hive will cool down to ambient sometime before sunrise (just looking at solar gain without any bees' heat to contribute to hive temp, which previous tests have shown can be substantial http://www.beesource.com/forums/showthread.php?291469-Winter-time-fun&highlight=winter+time+fun ).

Consequently, of the black wraps, roofing paper will show the highest temp spikes and the fastest temp changes, dropping down to ambient the fastest once the sun goes down.

JMHO


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## BeeCurious (Aug 7, 2007)

Thanks for going to the trouble of doing this!

Be sure to add some good Tags so the tread can be found more easily...


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## Mr.Beeman (May 19, 2012)

"Consequently, of the black wraps, roofing paper will show the highest temp spikes and the fastest temp changes, dropping down to ambient the fastest once the sun goes down."

True for an empty hive. Mass (bees, honey, frames, wax, etc.) will act as a heat sink and absorb the heat throughout the day and throw off heat during the dark hours.
Thanks again for the tests.


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## shinbone (Jul 5, 2011)

Mr.Beeman said:


> "Consequently, of the black wraps, roofing paper will show the highest temp spikes and the fastest temp changes, dropping down to ambient the fastest once the sun goes down."
> 
> True for an empty hive. Mass (bees, honey, frames, wax, etc.) will act as a heat sink and absorb the heat throughout the day and throw off heat during the dark hours.
> Thanks again for the tests.


I agree, but the general affect will still be the same - more insulation means smaller spikes and more gradual changes; less insulation means higher spikes and faster changes. Internal thermal mass and bees' heat will serve to smooth the temp cycling in each situation. Also, the larger a colony, the more heat provided by bee heat, and, consequently, the less the proportional contribution of solar gain to the internal temp of the hive.



BeeCurious - how do you add tags?


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## BeeCurious (Aug 7, 2007)

shinbone said:


> BeeCurious - how do you add tags?


At the bottom of the thread's page you will see the box...

I added two that you won't need to.


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## shinbone (Jul 5, 2011)

Got it. Thanks. Learned something new. Kewl!


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## BeeCurious (Aug 7, 2007)

shinbone said:


> Got it. Thanks. Learned something new. Kewl!


Search Engines will probably have them registered by tomorrow. Your photos will be showing up as well ... You're going to be famous!


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## shinbone (Jul 5, 2011)

BeeCurious said:


> Search Engines will probably have them registered by tomorrow. Your photos will be showing up as well ... You're going to be famous!


Haha. No autographs, pleeze . . .

More ignorance confession - what do tags do? Do they function the same as the words in the thread title?


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## Barry (Dec 28, 1999)

Mr.Beeman said:


> The results are pretty black and white.


What are they to you? It tells me that all the wrapping doesn't make much of a difference. At the end of the day, they equalize out.


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## BeeCurious (Aug 7, 2007)

shinbone said:


> Haha. No autographs, pleeze . . .
> 
> More ignorance confession - what do tags do? Do they function the same as the words in the thread title?



http://en.wikipedia.org/wiki/Tag_(metadata)


Not an easy read....


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## Mr.Beeman (May 19, 2012)

Barry said:


> What are they to you? It tells me that all the wrapping doesn't make much of a difference. At the end of the day, they equalize out.


Since you asked, to me, it clearly shows a heat gain during the day. You are correct however at the END of the day they equalize out in this spcific test.
I'm more interested in the heat gain that may or may not carry the bees through a cold night (like last night) in a real world application.


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## Michael Palmer (Dec 29, 2006)

Whatever the thermometers say, and the theorists say….

I keep bees where is stays cold all winter and some years there are no cleansing flights. I've seen the weather conditions almost but not warm enough for a good flight, and because the micro-climate around the hives is warmed enough by the black paper, the bees are able to take a cleansing flight…remaining within a few feet of the hive, cleanse, and flying back into the hive. Many will cling to the black paper…warming up enough to fly.

Wrapping probably doesn't help every year, but when it does, it does. I can install a wrap in a minute, and remove quicker than that. So, I figure, whether it helps a little or a lot, it's worth doing where I keep bees.


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## Barry (Dec 28, 1999)

Mr.Beeman said:


> heat gain that may or may not carry the bees through a cold night (like last night) in a real world application.


If I'm understanding the data correctly, by morning, they are all basically experiencing the same temp inside. Does a few degrees really make a difference in survival?


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## shinbone (Jul 5, 2011)

Just want to point out that the posted data photos are for a partially cloudy day. Results will be different for a full-sun day, which I hope to post once we have a weekend of sunny weather.


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## BeeCurious (Aug 7, 2007)

The mass of wax, wood, and honey would obviously absorb heat and contribute to the "warmth" of the hive's interior. 

Even without the heat sink effect of the interior's mass, a rise in temperature during the day would allow more movement, possibly permitting the cluster to move to that frame of honey that is often out of reach. 

An increase in temperature for whatever length of time will reduce the amount of honey consumption and that will be helpful in getting the bees through the night.... 

Avoiding the temperature spikes would be important in my opinion. 

The chart below might be of interest:


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## deknow (Jul 17, 2006)

A couple of thoughts....

1. The winter thermodynamics of a hive is complicated in the extreme. In addition to what has been mentioned, the bees do create airflow and I'm not sure how much the cluster is helped by raising the ambient temp in the air around the cluster...certainly it isn't universally beneficial.

2. I've been doing some similar experiments (no details yet) and settled on using a mocrocontroller (arduino ) and some little devices that look like small transistors but are really digital temp sensors. These are built on the onewire protocol... one lead is ground, one is an optional power supply (they work better if you give them power) and one is a data line.
The data line can also provide parasitic power, but each sensor has a digital address, and can be read individually.....even though they share a data bus (hence the onewire name).
They are accurate and relatively inexpensive.

Deknow


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## Mr.Beeman (May 19, 2012)

Barry said:


> If I'm understanding the data correctly, by morning, they are all basically experiencing the same temp inside. Does a few degrees really make a difference in survival?



A few degrees difference is all that separates life from death in some situations.


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## RiodeLobo (Oct 11, 2010)

Barry said:


> If I'm understanding the data correctly, by morning, they are all basically experiencing the same temp inside. Does a few degrees really make a difference in survival?


I would say most of the time no. However if that few degrees is the difference of a cluster moving to honey or not, just a couple of times in the winter it could make all the difference. I belive that last winter my survival rate would have been much better if I had wrapped my hives. The winter before and this winter I wrapped and have had far fewer colonies die out.


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## Barry (Dec 28, 1999)

That is an interesting graph, BeeCurious.
As Dean said, "The winter thermodynamics of a hive is complicated in the extreme." I'm not so sure a few degrees makes all the difference, especially in my winter climate, as well as Michael's. I keep my hives behind a building facing east. They get very little direct sun in the winter as there is another building to the south. They get protection from the prevailing weather from the west. I cant see how a piece of tar paper is going to make any difference on my hives. For hives sitting out in the middle of a field, perhaps some affect. There are just too many variables to conclude it helps or doesn't help across the board.


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## BeeCurious (Aug 7, 2007)

Barry said:


> There are just too many variables to conclude it helps or doesn't help across the board.


Too many variables? 

No direct sun would be the ONE big reason for hives not warming up during the day. 

"a few degrees"? The one hive wrapping system had an interior wall temperature 13° above a non-insulated box. To me, 13 degrees is significant.


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## Barry (Dec 28, 1999)

It is, but that is more than "a few degrees." That's a significant spread. There wouldn't be any degree change if I wrapped my hives. Well, OK, maybe one degree.

"Too many variables?"

Yes; sun exposure, hive placement, combs/stores, hive construction, snow/no snow, etc., etc.


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## jmgi (Jan 15, 2009)

Yes there are many variables involved in hive thermodynamics, but lets not make this way more complicated than it needs to be. Shinbone's test was done fairly, and the results are not surprising to me. I think doing a test using 15 roofing felt would have shown even more impressive results, maybe those kind of results are what some of you naysayers are looking for to make believers out of you.


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## BeeCurious (Aug 7, 2007)

Perhaps it's time for a couple of polls... 

Is there solar gain in the shade? 

Does the sun shine when there's snow on the ground?


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## crofter (May 5, 2011)

What is not being considered is the effect of wrapping on wind driven heat loss. Not through the potential cracks, but the heat loss from the hive when the boundary layer is constantly blown away. Still air conditions are not where wrapping really benefits.


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## JBJ (Jan 27, 2005)

Wrap half a bee yard and leave the other half unwrapped (we used roofing paper). When we did this we noticed the wrapped hives started flying in earnest hours earlier. It was a little unsettling when we pulled into the yard one morning and half the hives were very quiet and the other half was vigorously flying. Solar gain can have a profound affect on initiation of bee flight earlier. 

Something all orchardists should consider before the send us deep into the orchard under a full canopy. If the bees get to work earlier, more work gets done.


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## FlowerPlanter (Aug 3, 2011)

I like your tests.
Would the shielded hive be the best for winter survival? If your shielded material was black it would be even better.

Absorbing the sunlight is just part of the benefit of being wrapped/insulated.

Could you measure how long the hive can retain the heat? Maybe you could add a gallon of hot water to each hive and take temps as the water cools. I bet the shielded hive would do the best.


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## fieldsofnaturalhoney (Feb 29, 2012)

JBJ said:


> Wrap half a bee yard and leave the other half unwrapped (we used roofing paper). When we did this we noticed the wrapped hives started flying in earnest hours earlier. It was a little unsettling when we pulled into the yard one morning and half the hives were very quiet and the other half was vigorously flying. Solar gain can have a profound affect on initiation of bee flight earlier.
> 
> Something all orchardists should consider before the send us deep into the orchard under a full canopy. If the bees get to work earlier, more work gets done.


However, in winter, doesn't this wrapping/insulation/solar gain "fool" the bees into thinking it is warmer outside the box then it really is only to break from the cluster and enter the outside world to freeze? Or is this just an insufficient number of bees?


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## Mr.Beeman (May 19, 2012)

I did wrap my hives last winter with tar paper and did loose a few bees (100 or so max) per hive. It s pretty insignificant compared to the THOUSANDS that froze to death this winter as I did not wrap. I WILL wrap from now on and take the chance of loosing a few hundred.


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## mgolden (Oct 26, 2011)

Wrapping with black and insulation on three sides can definitely fool bees into cleansing flights when ambient it too cold.

In my first year, i added 2 inch of styrofoam on east, west and north side of hive as well as outer cover and under bottom board and then wrapped with black building paper. With that much insulation(minimal heat loss happening) and solar gain of south side, bees were being fooled into cleansing flights. Have added 1/2 styrofoam on front side in past two years and then black paper wrap and little false flights.

Going further, with a black wrap, I think one will get some solar gain but also there is considerable loss to the atmosphere on the sides out of the sun.


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## bluegrass (Aug 30, 2006)

BeeCurious said:


> The mass of wax, wood, and honey would obviously absorb heat and contribute to the "warmth" of the hive's interior.


I haven't been able to think of a good way to test this theory; but do you really think that 8 hrs of sunshine adding 10 or so degrees to a hives internal temp is going to increase 60-100 lbs of honey that is at ambient temp by any measurable amount? 

If you put that 80 lbs of honey in a pot on a tea light how long is it going to take to increase it by one degree?


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## bluegrass (Aug 30, 2006)

Mike: You can wrap all 700 of your hives in just over 11 hrs?

What do you do with all that wrap in the off season? Or do you just buy new every year and put last years pile in the landfill?


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## bluegrass (Aug 30, 2006)

Mr.Beeman said:


> I did wrap my hives last winter with tar paper and did loose a few bees (100 or so max) per hive. It s pretty insignificant compared to the THOUSANDS that froze to death this winter as I did not wrap. I WILL wrap from now on and take the chance of loosing a few hundred.


You had a thread on here last January about a hive which died, if you only lost 100 or so max I now know why it died and it had nothing to do with the wrapping.


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## bluegrass (Aug 30, 2006)

shinbone said:


> Haha. No autographs, pleeze . . .
> 
> More ignorance confession - what do tags do? Do they function the same as the words in the thread title?


scroll to the bottom of the main forum page and you will see current users. It will say something like 120 registered users and 524 guests. Many of those guests are "Spiders". They crawl web sites looking for key words to insert into search engine results. The tags concentrate search results. That is the short and sweet answer  save you all that reading on something that doesn't "mater".


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## Mr.Beeman (May 19, 2012)

bluegrass said:


> You had a thread on here last January about a hive which died, if you only lost 100 or so max I now know why it died and it had nothing to do with the wrapping.



LAST January would be THIS winter in which I didn't wrap. I wrapped LAST winter (not this winter) and only lost hundreds.
Hope that clears things up for you.


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## Daniel Y (Sep 12, 2011)

bluegrass said:


> If you put that 80 lbs of honey in a pot on a tea light how long is it going to take to increase it by one degree?


I would not compare Solar energy to a tea light. Actually I suspect that not only woudl the honey serve as a far better source for the heat to be transferred to. But I also suspect it will hold onto that heat for much longer. This test is measuring air. Keep in mind air is a poor conductor of heat and gives it up readily. I would be interested in the same sort of measurements but with the probe on frames of honey. It might lend some understanding of why bees tend to not only have honey on their outside frames. but practically wrap themselves in it.

The air temperature that is being measured will only remain stable or even rise a bit due to a constant and fairly strong source feeding it. as soon as that source is gone the air will cool rapidly.

For example, you car setting in the sun with the windows up. It gets hot inside. The seat is to hot to set on the steering wheel to hot to touch. but as soon as you open the door what is the first thing that cools off? You can actually feel the air cool. This is partially due to the air can move and be replaced with cooler air. this is true. but a lot of that cooling is due to the airs ability to release heat.

How do we know that air releasing heat is part of why the air cools so fast? Think about it. not everything can give up heat as fast as air can. the steering wheel cannot. the dash cannot the seat cannot. If the air could only give up heat at the same rate those other objects could. the air would remain as hot as they are. In fact they are all pumping heat out attempting to do just that. but they cannot keep up with airs rate of heat loss. We quickly learn that if we move more air across those hot objects that they cool even faster. Roll down the windows and drive. 

Truth is air serves best as a means to carry heat away. it cannot serve both as a coolant and a heat storage. For this reason measure air for a reading of warmth is not the best choice.


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## Hogback Honey (Oct 29, 2013)

Yes Thanks so much for sharing! That was very interesting and informative.


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## bluegrass (Aug 30, 2006)

Mr.Beeman said:


> LAST January would be THIS winter in which I didn't wrap. I wrapped LAST winter (not this winter) and only lost hundreds.
> Hope that clears things up for you.


Not really; I call Jan 8th 2013 last winter: http://www.beesource.com/forums/showthread.php?277142-Ok-I-need-answers


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## Bob J (Feb 25, 2013)

Much appreciate your excellent work!


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## Michael Palmer (Dec 29, 2006)

bluegrass said:


> Mike: You can wrap all 700 of your hives in just over 11 hrs?
> 
> What do you do with all that wrap in the off season? Or do you just buy new every year and put last years pile in the landfill?



No, of course not. There's more to it than putting on the wrap. Time for the wrap alone is a minute...so in an apiary it adds a half hour to the job. Wort the time in my opinion.

The wraps are held on with 4 staples in the back of the hive where the paper comes together, and two be the upper entrance. In the spring, you pop the staples off with the corner of the hive tool and the wrap falls off. Fold it sling the creases made by the hive corners and put away fon another year. They last for years.


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## Mr.Beeman (May 19, 2012)

Good to know bluegrass. I appreciate your insight.
I also read through some of your past posts and are getting a better understanding of your personality. What I can't figure out is if you are a "glass half full" or "glass half empty" personality. 
I have a hunch though.
How long have you been a nurse? I was in the medical field myself years back.


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## bluegrass (Aug 30, 2006)

Mr.Beeman said:


> What I can't figure out is if you are a "glass half full" or "glass half empty" personality.


I am more of a call it half full or half empty, it is all the same kind of a Guy. 

I started in Nursing in 08, worked as a commercial truck driver before that and about a dozen other things.


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## Acebird (Mar 17, 2011)

Without measuring temperature over time you don't know the heat loss or gain. You really need data acquisition to do this.

I suspect what MP said highlights the benefits of wrapping. Whether or not early flight ends up in a net gain of work done will depend on heat loss when the sun goes down. You could gain time in the morning and loose it all in the evening.

I don't wrap and I have wide open SBB's. I can't say that wrapping increases survival where I live but it might affect production. Production is not my focus so I wouldn't know if it helps or not.


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## BeeCurious (Aug 7, 2007)

Acebird said:


> I can't say that wrapping increases survival where I live but it might affect production.


Really? 

What would they be "producing" when it's normally too cool / cold to fly and there's nothing in bloom?


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## Acebird (Mar 17, 2011)

Brood. If the colony comes out of winter stronger, greater population then the assumption is it will produce more.


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## bluegrass (Aug 30, 2006)

Acebird said:


> Brood. If the colony comes out of winter stronger, greater population then the* assumption* is it will produce more.


Thanks for recognizing that that is an assumption. There is a second assumption that brood rearing earlier increases consumption and makes supplementary feeding necessary. That is the assumption I subscribe to. I have been unable to find any indication that wrapped hives vs unwrapped increases production of honey over the course of the season; I don't think anybody has actually assessed long term production in relation to wrapped hives. I have seen home brew trials that do in fact show larger populations earlier in the spring with wrapped hives.

If you what big populations for early splits, queen rearing, or you just like your bees to swarm in April, wrapping is the way to go. 

I know they give you a hard time around here, but I like you. At least you think stuff through logically, even if sometimes you take the thinking too far


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## Daniel Y (Sep 12, 2011)

I will take Ace's thought even if they are wrong or mistaken over the non ideas any day. At least he is applying his mind to the issue. He gets heat only because he speaks up. Then those very same people that do that can't figure out why more people do not contribute. Worse than that they then claim that it is some lack of character in those people rather than seeing where the real problem lies. So even if the ideas are annoying. it is accomplishing more than most. It is giving you all what you ask for. Sort of like asking someone to sing. they may very well do it. you may very well not enjoy it. Keep the comments coming Ace. I tend to read most of what I see you write. I can't say that for everyone.


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## Grizbee (Sep 23, 2009)

today was the type of winter day that I am glad I wrapped my hives in tar paper. Very cold, I don't think we broke 6-8 degrees for a high temp, but the sun shone all day, and march sun does have some return to some good solar gain.This last sub-zero cold snap has me a little worried about my bees,w/ no cleansing flights since November. Anxiously awaiting a weather break to check the bees, and do some feeding.


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## Mr.Beeman (May 19, 2012)

- 14 actual air temp in mount pleasant, mi tonight.


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## Daniel Y (Sep 12, 2011)

Wow, I feel for you all. It is 3 a.m. here about as cold as it is going to get and 43 degrees. That is not normal for us but I am enjoying it. My wife said she saw the first dandelion yesterday. We have been doing inspections for the past 3 to 4 weeks. Adding some space to some hives. Getting ready for them to attempt to swarm. Nucs are lined up we nearly have all the frames made for nearly 100 new boxes of one type or another. I need to get the divider material and make up to as many as 250 2 frame compartments. That is what I call ready for swarm season in comparison to last years 18 supers we where making when it hit. Last year I never was ready for anything. This year I am going to find out just what bees can do. It is known to split the spring around here. that means we could get winter to return with a vengeance over the next few weeks. I am betting it will not.


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## Michael Bush (Aug 2, 2002)

>The wraps are held on with 4 staples in the back of the hive where the paper comes together, and two be the upper entrance.

Wow! That would blow off in about five minutes here in Nebraska...


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## Michael Palmer (Dec 29, 2006)

There's a string around the wrap and over the top. I have bees in windy locations and the wraps don't blow off.


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## v45 (Apr 1, 2012)

I would love to see this test with bees in the hives to account for the heat the bees generate.
I have been wondering the same thing if you had the reflective insulation or 1" of foam board covering the sides if it would help keep the heat in better but limit the solar gain during the day?
I like wrapping the hives in #15 lb. tar paper with a 1" foam cover. In my location it wont get above freezing for weeks. I believe the tar paper wrap and having the hives against a South facing fence allows the hive to warm up in the day so they can break cluster and move to the food


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## fieldsofnaturalhoney (Feb 29, 2012)

Grizbee said:


> today was the type of winter day that I am glad I wrapped my hives in tar paper. Very cold, I don't think we broke 6-8 degrees for a high temp, but the sun shone all day, and march sun does have some return to some good solar gain.This last sub-zero cold snap has me a little worried about my bees,w/ no cleansing flights since November. Anxiously awaiting a weather break to check the bees, and do some feeding.


Literally, no days with bees doing cleansing flights since November, even with that tar paper ?


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## shinbone (Jul 5, 2011)

v45 said:


> I would love to see this test with bees in the hives to account for the heat the bees generate.


The presence of bees definitely will add heat to the hive. From the minimal testing I have done, the heat produced by a good sized healthy cluster is much bigger than the heat produced by solar gain.

The problem for me is, introducing bees into the test introduces a huge number of variables which are beyond my resources to control for to do a good test. Consequently, I did the solar gain test without bees to isolate its affects. I've done other test which show that under some circumstances, the bees heat the interior of the hive by as much as 80F. This compared to the 10F or so seen in the few measurements I have on solar gain, so far.

Thus my conclusion that solar gain is the smaller of the two for a heat source. I am not saying that solar gain is not helpful, or can never make the difference between a hive's survivial or its death. Just that a good size cluster on its stores can produce substantially more heat than solar gain. In other words, the key to winter survival is a good size cluster with plenty of honey stores, not wrapping. Those in winter climes much harsher than Denver, Colorado, may indeed need both to survive a winter. 

Also, I read somewhere that wrapping can help with early brooding, which may be enough of an advantage by itself to justify wrapping hives.


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## bluegrass (Aug 30, 2006)

Adding a colony of bees to the equation completely eliminates any ability to measure trends as the size of the cluster and the amount of honey they consume/energy they burn will impact the readings... So a large and gluttonous hive with no wrapping will have much higher temps then a wrapped one with a small cluster and vs versa. Solar gain is so minimal it has to be measured by it's self. I have a feeling that even doing it on full honey supers would make the gains so minute that measuring them will be difficult. 

I remember growing up in VT on the farm we would have Wrapped round bales that even sitting in the sun all day would be frozen in the center well into May. You start adding mass to the equation and it completely changes the picture. It takes more then heat to warm up mass, it takes energy and lots of it.


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## Acebird (Mar 17, 2011)

shinbone said:


> The presence of bees definitely will add heat to the hive. From the minimal testing I have done, the heat produced by a good sized healthy cluster is much bigger than the heat produced by solar gain.


You belittle your findings. Look up the calories in one pound of honey. A hive is a small structure and the sun is at such a low angle in the winter that solar gain is no contest. If the bees could not shiver as they do the colony would be toast. Or I should say bee crystals. The work that the bees do in the winter is what keeps them alive.


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## Grizbee (Sep 23, 2009)

fieldsofnaturalhoney said:


> Literally, no days with bees doing cleansing flights since November, even with that tar paper ?


yes, this winter in N Michigan has had no winter thaw,enough for good flight, it hit 40 degrees on Jan. 14, and 36 on Feb. 19, then back to the 3rd sub zero 10 day or so stretch this year. the snow here is very deep,probaly have hit 190 inches and counting. It is supposed to hit the 30s by the end of the week, I am going to make some quick checks, and do a body count on the 20 I have in the back yard. the good news is they are deep in the snow which can be the best insulation, and the melt will give us good moisture in this sandy soil.


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## dp2k (Apr 22, 2012)

Very interesting thread – Thank you shinbone for your work in kicking it off. If I understand the responses correctly, the most significant arguments for and against wrapping (with 15# black roofing paper) are:

Wrapping a hive with 15# black roofing paper may NOT have any positive effect because:
1)	The mass of the honey/comb/frames/bees may be too large to heat up from the minimal temperature increase caused by wrapping.
2)	Regardless of any increase in the hive temperature during the day, the hive will still cool down to the same temp as an (identical) unwrapped hive overnight, negating the value of wrapping during the day.
3)	Increase in temperature during the day can “fool” the bees into taking cleansing flights on days that an unwrapped hive would be too cold for a cleansing flight. These cleansing flights can be fatal to the bees. 
4)	Warmer hive temps during the end of winter will cause them to start raising brood earlier. A cold snap could kill off (some or most of) the brood because it would be outside cluster. Earlier brood rearing may lead to earlier swarming. 
5)	Wrapping the hive to raise the temp a couple degrees in winter won’t have an effect on honey production during the summer. 
6)	Wrapping the hive is a waste of the beekeepers time, money and effort. 

Wrapping a hive with 15# black roofing paper may have a positive effect because:
1)	The increase in temperature within the hive may raise the average temp enough that there is a benefit the bees from 1) less effort to maintain the necessary temperature to ensure survival of the cluster and/or 2) the ability to move to honey outside the cluster to avoid starvation. 
2)	Wrapping the hive will cut down on the negative effect of the wind 1) carrying away heat, and/or 2) blocking wind from directly entering cracks/knots/holes in the hive.
3)	The increased warmth will allow a larger cluster of bees to survive the winter, and allow the bees to start raising brood sooner in the spring, resulting in a stronger hive earlier in the season.


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## fieldsofnaturalhoney (Feb 29, 2012)

Grizbee said:


> The good news is they are deep in the snow which can be the best insulation, and the melt will give us good moisture in this sandy soil.


:thumbsup: :thumbsup::thumbsup: Can I borrow a thumb?


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## julysun (Apr 25, 2012)

What were the wind conditions and humidity? Without that the tests are weakened to near useless.
How soon did each hive reach equilibrium temp.? The wrapped could take much longer saving bee work.
The wrappings are poorly sealed AT THE TOP, causing them to act as a heat pump circulating the warm boundary air out for frigid outside air. Major fail.
From an insulating prospective a large, captured air space under the wrappings is desirable, especially tar paper, a poor insulator its self. 
I think empty hives are a poor test bed for full ones. Hive dynamics are what drives bee life and should be tested underway.
Any way, I had to smart off about something today. :lookout:


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## Mr.Beeman (May 19, 2012)

Since this was a SOLAR GAIN TEST ONLY maybe you can take it one step further and perform an insulative test with occupied bee hives. The combination of the two tests could reveal some dramatic results. Looking forward to your test results.


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## bluegrass (Aug 30, 2006)

julysun said:


> The wrappings are poorly sealed AT THE TOP, causing them to act as a heat pump circulating the warm boundary air out for frigid outside air. Major fail.


If sealed up tight the inside of the hive becomes a wet moldy mess of dead bees... Been there, done that.


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## Grizbee (Sep 23, 2009)

sometimes my reply to people who ask why I wrap in tar paper, "to make the beek feel better", but the reasons I do it is to give the bees that solar this time of year where the sun has some solar power again, to perhaps move to honey stores in super cold weather like we have had this last week, below 0 overnite.I'm watching snow melt off my roof in the sun at 18 degrees right now. Also when I do snow shoe in to my yards, the black paper melts back alot of snow, much less shoveling on this old tired beek back. no reason to overthink this, simple solution that seems to help the bees a little


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## julysun (Apr 25, 2012)

Of course you vent the hive, but for insulation value the top of the insulation should be blocked. This prevents heat rising, sucking cold air under the insulation. Or so it appears to me.


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## Acebird (Mar 17, 2011)

I would agree. If you let air flow chimney between the paper and the hive then you may solve the moisture issues but you certainly had negated the heat gain benefit.


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