beehive heater - Page 1
Forum section: electronics / projects

author: metrologist
author_rank: Super Contributor
timestamp: November 19, 2019, 03:45:14 pm
content: My neighbor has beehives and they were talking about installing some kind of heater to keep the temp at 107F (42C) for a few hours or so when needed to kill bee mites.I'm thinking of helping them with the build, but I don't have an intuitive sense of a few things. The bee hives are made into a box from wood planks, and there are honeycomb frames. The typical kind of setup.Some of the ideas are to string nichrome wire around inside the box or through the frames, or otherwise set up a heating tube with a fan. What size wire gauge should I consider if stringing through the frames (i.e., is 30ga too thin)? I'd probably try 24ga for a heating tube, and I think a heating tube would be easiest. If ambient temps are 40F (4C), about how much power do we think we need? The hives are currently wrapped in ~2inches of foam board insulation. I would use a few temp sensors and Arduino for control.

author: Stray Electron
author_rank: Super Contributor
timestamp: November 19, 2019, 04:00:59 pm
content: I wouldn't use a bare nichrome wire or anything like that as a heating element. Sooner or later dust or bee wax or other debris will build up on it and when the heater comes on and gets hot, it's going to start a fire. I would only use some kind of heater where the heating element is embedded in a tank of oil or other liquid. It will supply the same amount of heat but at a lower (and safer) temperature and the greater mass will hold down the temperature swings.I would use something like this as a heater.https://www.amazon.com/oil-space-heaters/s?k=oil+space+heatersMost of these already have a built in thermostat but if the heater was placed under the hive it may not be accurate so I would add a second and maybe a third thermostat located in the hive.I've never heard of heating a hive to get rid of the bee mites. Can the bees withstand that kind of temperature or do they need to be taken out of the hive first? Also does that temperature damage the wax combs?

author: metrologist
author_rank: Super Contributor
timestamp: November 19, 2019, 06:13:00 pm
content: This is a commercial version available in another country:https://www.vatorex.ch/en/beekeeping-solutions/varroa-solution/Apparently, they cannot import to the US, or it's too costly. I did not research that.Beeswax melts at a higher temperature, ~140F. But I think a lot of wire would need to be strung through the combs to have effective heating since you can't let the wire get much hotter than the desired temperature. This is why I was considering an air heated system.

author: james_s
author_rank: Super Contributor
timestamp: November 19, 2019, 06:54:19 pm
content: How about a good old fashioned incandescent lightbulb? They are quite efficient as heaters. If the light is a problem they can be enclosed in an opaque metal box. Putting two identical bulbs in series will dramatically extend the life and substantially reduce the amount of visible light produced.

author: Gyro
author_rank: Super Contributor
timestamp: November 19, 2019, 06:58:43 pm
content: I don't know how the bees would tolerate it, but I would have though blowing in warm air would be the most effective way of uniformly heating such a skeletal structure. Probably with some form of temporary outer thermally insulated cover (Edit: which it sounds like you already have).Is this a frequent treatment? You mentioned several hours. I suspect it comes down to whether it is something that needs to be permanently installed versus something you can sensibly carry to individual hives.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: November 19, 2019, 07:24:54 pm
content: I have never heard of this (my dad used to keep bees to pollinate the orchard on the small holding where I grew up) but a Google foundhttps://www.vatorex.ch/en/products/vatorex-system/hyperthermy/which is quite interestingDon't kill your bees!

author: iMo
author_rank: Super Contributor
timestamp: November 19, 2019, 07:37:41 pm
content: Vatorex says:QuoteIt seems the heaters are inside each honeycomb. Maybe a hot air would be a solution too.https://www.thermosolarhive.com/thermosolar-hive-technology-in-nutshell/Wiki:Quote

author: Brutte
author_rank: Frequent Contributor
timestamp: November 19, 2019, 09:07:55 pm
content: Quote from: metrologist on November 19, 2019, 03:45:14 pmThings to consider:First, beehives are usually located in remote places, without mains in proximity.Second, is it: "To keep the temperature 41.95C to 42.05C" or more like "40C to 44C will do"?Third, how often would you like that to happen? You have to attend beehive anyway so is WiFi and autonomous operation necessary?I like simple designs. I'd consider making one frame with a container with substance that changes state of fusion at a temperature little higher than 42C (experiment needed). Then you cannot f%@ck it up. No controllers, no wires, no electricity, no arduino and no bugs.Ca(NO3)2*4H2Omelts at 42.7C, is non-toxic and if you buy a pure one (and not the industrial or agricultural dirty grade) it will stay at precisely 42.7C all the time, till it completely solidifies. The state of fusion is around 120kJ/kg so perhaps first estimate how much energy your plan requires.

author: metrologist
author_rank: Super Contributor
timestamp: November 19, 2019, 09:13:32 pm
content: I'm not into beekeeping personally, but find it interesting to help the neighbor. Their frames have a thin plastic honeycomb foundation in each frame. I suggested drilling holes so nichrome wire can be threaded throughout the frame.Would 44ga nichrome 80 wire be too thin? I haven't found current rating of that. I checked copper wire at that gauge can handle 20ma. I was thinking a 24V source, so that's not a lot of watts. I'm estimating about 64 feet of wire per hive box. That would be 8 feet per frame. 36ga nichrome at 68F is 26ohm/foot, or 208ohm per frame. 24V comes out to just under 3W per frame, or 30 watts if all frames wired in parallel.

author: james_s
author_rank: Super Contributor
timestamp: November 19, 2019, 09:19:26 pm
content: 44 gauge anything is difficult to work with, it will snap in two if you just look at it wrong.

author: metrologist
author_rank: Super Contributor
timestamp: November 19, 2019, 09:20:59 pm
content: Quote from: Brutte on November 19, 2019, 09:07:55 pmProbably 41C to 42C will work. Were thinking solar power. Also, the complication of bee thermal managing brood temps makes central heating less successful. There is already a temp, humidity, and weight monitoring system that is bluetooth and wifi, but I'm not sure if it could be tapped in to. It also requires a visit to the hive proximity with a mobile device to download the data. Some other details were posted by others above.

author: Gregg
author_rank: Super Contributor
timestamp: November 19, 2019, 09:40:24 pm
content: Electric blankets and heating pads often have nichrome wire with silicone or PTFE insulation. A thrift store electric blanket could be taken apart and the heating wires shortened to work suitably with solar panel voltages.

author: floobydust
author_rank: Super Contributor
timestamp: November 19, 2019, 09:45:34 pm
content: I suggest not make your own heating element - open nichrome will be hot and can generate smoke or burn local materials, plastics. Beehive heaters already exist. Even several 25-50W power resistors mounted to an aluminum plate is better. Reptile/terrarium mats.FlexWatt heat tapelooks interesting. Some 3D printer heating plates might work. The bees apparently will chew on some materials.You'd have to estimate how much heat is required. It depends on the delta T needed and the construction of the beehive, for heat loss. I see ~10W to 50W.From winter and spring heating, you can see given delta T, the energy needed in this old 1950's research paper 1,500 thermocoupleshttps://beesource.com/resources/usda/electric-heating-of-honey-bee-hives/They found conduction heating best.Include a high safety-limit switch in case the controller crashes or malfunctions.