Heating hives

[boca]

Of course not. How brood are could be bigger than occupied frane area - never...

If the heating system works at a constant power, or switched on-off not in line with the outside temperature, then it can make damage.

With temperature fluctuation the cluster size expand/shrinks. With careful control fluctuation can be attenuated, with not careful heating it can be amplified. Then brood can chill.

[Finski]

Of course not. How brood are could be bigger than occupied frane area - never...

If the heating system works at a constant power, or switched on-off not in line with the outside temperature, then it can make damage.

With temperature fluctuation the cluster size expand/shrinks. With careful control fluctuation can be attenuated, with not careful heating it can be amplified. Then brood can chill.

That needs imagination.
temp fluctuates normaly quite much.


Bad weathers makes damages to brood if half of field bees die in spring. The sun invites out and then a rainshower hits bees down.
Chalkbrood hits often into brood area.
This has nothing to do with heating.

[BlueBee]

Boca, it sounds like you’re going to have an interesting winter!  I like the looks of your AC switching board. 

You might get a kick out of this photo :-D  One of the problems with using a computer power supply.


There is a computer power supply in this nuc, under the snow.  The orange wire going in is a 120VAC extension cord.  The black wire coming out is 12volts DC.  Inside the nuc is my 500W computer power supply.  There are NO bees in this nuc.  This insulated nuc is just used to keep the power supply from FREEZING up!

Semiconductors tend to run better at cold temps, but the electrolytic capacitors don’t like the cold :(  There are some big electrolytics on the output filtering stage in a power supply.  Hence I needed a foam hive just to keep my power supply warm last winter. 

Power supplies are not 100% efficient and most computer power supplies are probably going to waste 15% of their input energy as heat. So if you just put a power supply in an insulated box, the thing will warm up the box so the caps don’t freeze up.  If you’re drawing 120watts from the power company, the power supply itself is going to be a 18 watt heater.

[BlueBee]

Finski, what do you think the temperature is inside your poly hives at the walls?  What about the electric nucs, at the walls?  I know the bees themselves are warm, but what I’m wondering about is the warmth of the environment inside your hives (around the bees).  How much warmer than the outside air in general would you guess? 

If I do any experiments with electric this winter, my goal is going to be to program my controller to hold the temperature in the hive (near the walls) to about 50F/10C.

[Finski]

I answered to that allredy

Bees control their own heat. (if they can)

 I have pushed digital thermometers sensor into the hive, winter cluster has 23C temp.  If I disturb the hive only walking outside, the hive may rise its temp up to +40C.

Before cleansing flight bees start brood rearing in late February and rise core temp to +36C.

In my climate under 5 frame hive does not survive over winter.
In wood shelter it makes better.

It is vain to measure "how warm inside" because the out door temperature fluctuates  +5 C--- 5C, -10C -- 20C, sometimes -30C.

In Spring winter temp may be near zero by day and -20C at night.

[Finski]

If I do any experiments with electric this winter, my goal is going to be to program my controller to hold the temperature in the hive (near the walls) to about 50F/10C.

When beekeepers winter bees in cellars, there temp must be under 7C. That keeps bees in winter cluster.

It is near the temp where a bee goes into choma without external heating aid.

[BlueBee]

Since this thread is about electric heating, let me throw this idea out :-D  Has anybody ever considered cooking their bees with enough heat to kill mites and other pests?  With all the insulation in our hives if we were to add a few more watts of heating power to our systems, you could raise the temperatures in the hive to 115F / 46C if you wanted to.

Finski, have you ever tried to cook your bees to kill the mites?

I read in another forum some beeks in Uzbekistan do this to kill varroa!  Yeah, I’m going to have to get out my globe again to remember exactly where Uzbekistan is located...

[Michael Bush]

>Has anybody ever considered cooking their bees with enough heat to kill mites and other pests?

As soon as the bees get overheated they regurgitate honey all over and make a sticky dying mess... if you could stop precisely before that point, then maybe it might work.

If you do it for any length of time you'll just over work the bees trying to cool it down.

[boca]

Has anybody ever considered cooking their bees with enough heat to kill mites and other pests?

Of course! How can you not think about come up with a method of keeping in control such a pest. I could not experiment seriously this year, because I had only two hives. Every single worker bee is a treasure. Next year if I still have bees I will take a more courageous approach.
(by the way; the whole summer I have not seen a single varroa fallen to the bottom, so I am not treating with formic acid, only oxalic acid in December)

I have the feeling that heating the whole brood nest above its normal temp makes more harm than benefit. 
I read in an article that  slightly higher temperature applied on sealed brood for a short time kills lowers the number of mites significantly without serious damage for the pupae.

So the plan is:
- The object of the experiment is not a colony but a frame of sealed brood. The cells can be counted, statistically more accurate.
 -The pupae have to be very close in age (resticting the queen to the frame for a short time).
 - In an incubator different temperatures are applied for various time.

[Finski]

.
Cook bees?
I enjoy enough when I read beemaster forum.
Too much fun to process....

[boca]

Control of Varroa: A Guide for New Zealand Beekeepers
Page 62:

Studies show that if the brood is heated
to 44oC for 4 hours, 100% of the mites in the capped brood will be killed. Only about 5%
of the brood itself is killed in the process, mostly in the form of older larvae that crawl out
of the cells. Heat can also cause some deformities in adult bees that develop from old
pupae that have been treated. There is no noticeable affect on the life-span of bees
emerging from heat treated comb.

It does not say where the studies are.

It must be a fun when larvae crawl out  :)
Otherwise does make sense to me. Bees kill hornets by generating heat in a cluster.