Translate

Tuesday, June 23, 2015

The Making of a Hive: Part 1 of 3

Updated: Added link to Part 2

When David Liedlich gave a talk on double-walled, insulated Russian hives this past spring, he was speaking straight to me. I was devastated by the loss of three colonies due to condensation, and I had to know more about this approach. Then I read Fedor Lazutin's book Keeping Bees with a Smile which discusses Russian horizontal hives, and it was a total eye-opener. I learned so much about bees and why they do what they do. Plus, it answered a bunch of questions I had regarding overwintering. If you haven't read this book yet, I highly recommend it. It's about $35 on Amazon, and it's worth every penny. "Part IV, How Bee Colonies Winter, and How to Make Wintering as Successful as Possible" is pure gold.



For awhile I considered building a Russian hive, but after a few email exchanges with Lazutin's editor, Dr. Leo Sharashkin, I opted not to. The thing about the Russian hive is that it uses double height frames (about 18"-23" high, I believe). Because they're so big, Sharashkin recommended using wire and foundation, both of which are items I want to avoid. Additionally, I'm not so sure how well crush and strain harvesting would work with a wired frame. Also, I don't have enough hives to justify purchasing an extractor large enough to accommodate these huge frames. Instead, I decided to continue with my TBHs, but I wanted to build one that incorporated some of Lazutin's ideas.

Fedor Leonidovich Lazutin

The Cluster

Before diving into Lazutin's ideas on hive building, I think it's important to skim over a few (though not all) of his notes on the bee cluster because he discusses it at length and it informs the design he uses to a great extent. 

Young bees that are least able to handle huge temperature fluctuations remain in the center of the cluster and form a loose "core." Older bees create a tight exterior "crust" 1"-3" thick, depending on colony strength. The purpose of the colony is to generate enough heat to keep the outer bees between 43°-48°F. If the temperature drops below that, the outer bees will fall into a torpor and die unless the ambient temperature is raised.



Bees in the cluster core, emanate heat while the bees who are tightly packed into the crust, trap that heat inside the cluster. In order to maintain the correct temperature, bees need to consume honey. However, there are a couple of challenges for them because 1) the honey has to last until the spring flow begins and 2) Excess honey consumption leads to excess intestinal content (diarrhea, etc.)
Heat Loss

Large clusters are better able to maintain a stable temperature. They also tend to consume less honey overall than smaller clusters because they don't need as much fuel to stay warm. By reducing heat loss in the hive, beekeepers can also help bees retain that heat. Heat escapes from the hive in two ways:

  • Direct thermal transfer. The hive's walls, top, and bottom account for the majority of the heat lost.  Therefore, walls and particularly the top of the hive need careful insulation.
  • Through vents. The amount of heat lost this way depends on the location and sizes of the open hive entrances. However, Lazutin says that if vents are properly placed (i.e., allowing only enough air exchange for breathing), then vents will account for less than 10% of the total heat loss.

Respiration

I will freely admit that I didn't read this section carefully because there were too many numbers, and I'm a words and pictures kind of person. However, this is what I took away from this section:

  • A single small entrance provides sufficient fresh air. 
  • Excessive air exchange with the outdoors allows heat and carbon dioxide to escape. Carbon dioxide actually helps bees overwinter as long as CO2 levels do not exceed 4%.
  • When the hive has a single entrance, diffusion (rather than ventilation) is what creates an exchange of interior and exterior air. "In other words, if... the concentration of oxygen in the hive is lower than in the outside air, then oxygen molecules will pass from the outside into the hive even without an actual air flow." 
  • There is no point in insulating a hive as long as there is steady cross-ventilation from upper and lower entrances.

Moisture

We all know that moisture is a killer. I discovered this first-hand last spring. Warm air condenses on cold surfaces. If the moisture collects on the bees, it makes it hard for them to heat the hive.

Again, there was lots more math in the book, but the salient points were that consuming honey causes the colony to produce moisture. In order to get rid of water, they need to bring in outside air. Bees actually need more air to get rid of the water than they need to breathe. While a single small entrance is fine for respiration, it won't cut it when it comes to getting rid of moisture. 

Lazutin asserts that proper insulation above the colony is paramount. Without it, hot air does not condensate on the walls. Instead, it rises above the winter cluster, condenses, and drips onto the bees. As it does so, the cluster's crust dies off. Sufficient insulation causes moist air to condense on the hive walls away from the cluster.

However, in addition to insulation, we need to deal with the moisture itself, and there are two possible approaches.
  • Remove moisture using ventilation. Cross-ventilation is probably the method that I hear of most beeks using. Provide an upper and lower entrance. Cold air comes in at the bottom. Warm air exits at the top.

    Bottom ventilation is another possibility. In this case, a slit is opened across the entire length of the hive or a large hole is cut into the bottom of the hive.

    Lazutin argues against ventilation because he says that in addition to removing moisture, it removes too much heat. It also causes bees to consume more honey -- which means they could clog up their digestive tracts, or run out of stores too soon.
  • Leave moisture in the hive. Water-absorbent materials can be placed in a hive -- either above the colony, under the colony, or to the sides of it. (Note: This is the principle behind the Warre quilt.) This practice decreases the exchange with outside air and minimizes heat loss from ventilation.

    Lazutin also recommends leaving a minimum 2"-3" of space under the bottom of the frames, below the entrance. The dead space means that the bottom of the hive will be warmer due to the still air below the entrance. It also promotes better air exchange in the nest.

    Even better, Lazutin recommends leaving 5" below the entrance. He asserts that this will help control varroa. If the space can be filled with hygroscopic materials, it will create an even warmer bottom while absorbing excess moisture. (Note: Kind of reminds me of Phil Chandler's eco-floor. Hmmm... Maybe that will be my next project.)


The Hive

In pages 300-301 of his book, Lazutin describes the characteristics of an ideal hive. Last week, I built my own double-walled, insulated hive. I couldn't necessarily create all of his conditions in my own hive (especially leaving 5" below the entrance and 18" tall combs), but I tried to incorporate his thoughts as well as I could:


  • Warm walls. He says tree hollows in old-growth forests have walls 4"-6" thick. I looked up the R-value for 6" thick wood. While the number varies by type of wood, it's about R-9. I estimate my side walls are R-9.5 to R-10.5.
  • I was concerned about using insulation in the end walls because I didn't want to take up too much interior space during peak flow times. My workaround is a double thickness entrance. In the winter, I'll add some insulation to it. In the fall, I plan to use a second divider board behind the regular divider that is made of foam insulation. A rather innovative friend suggested this to me, and he calls it "The Polar Jacket." 
  • The entrance is 2" from the bottom of the hive. Not exactly beneath the bottom of the cluster, but there's not much wiggle room in a TBH.
  • In the winter, I plan to add a container of silica gel for moisture control.
  • I'm thinking about adding a layer of insulation to the bottom of the hive as well.
  • Although I haven't done it yet, I plan to build an insulated roof before winter strikes.


In Part 2 of this series, I'll show the actual building process.

6 comments:

  1. You've certainly done your homework researching this topic! I've always put insulation above the top bars in the winter by just laying some on top of the bars (rather than building an insulated roof. I use the silver sided bubble type insulation. But this past winter, I noticed more moisture buildup than the previous year, so was thinking of skipping it this year. But perhaps not after reading this. I might leave a slight gap between a couple of bars behind the follower board for some top ventilation since my follower board is leaky. It will be interesting to see if they propilize it shut though - they have a habit of doing that.

    ReplyDelete
    Replies
    1. What if you opened it up after they start to cluster? They might be mad as all get-out if you do it, but they also might not have the time/ability to seal the crack.

      Delete
    2. I have asked many people and got no definitive answer: does the silver side of the insulation go up or down?????

      Delete
    3. I think you're asking the wrong person because I know less than nothing about construction!!! However, I've always heard that the foil has to face the open air (so that would be the outside). I've also seen photos of hives belonging to a top-bar beek in my state who gives classes, and his are wrapped for winter with the foil on the outside.

      Some insulation comes with foil on both sides, though, so I'm not sure why that works since a reflective side will be against whatever is being insulated.

      Delete
    4. I'm new to bee-keeping, but I would suggest turning the foil in, towards the bees. Foil is normally used as a reflective agent for radiant heat. It would reflect the bees' heat back into the hive.

      Delete
    5. Thanks for clarifying that point about the foil!

      Delete

Thank you for your comment! I can't wait to hear what you think!