# Designing a large scale drum warmer



## Nohoneyno (Jan 31, 2012)

Hi there,


I originally posted most of this as a reply to another thread but thought I might start my own one too as I think our needs are different and I want to address some different issues.

I work for a speciality honey company in the UK. I am trying to address the energy use of our small honey packing factory. I want to reduce our electricity and gas consumption, to reduce costs and CO2 emmissions. Electricity is expensive here and there are various grants and tax breaks for emmission cutting initatives. 
(and we dont want to wreck the planet, so there will still be honey for our sons to crop! but thats another issue that i might put in a different thread)

Our biggest consumer of energy is our honey heating process. I want to design a quick and energy efficient system for melting barrels of crystalised honey. At the moment we need to melt about 50 barrels of honey a week, to maybe double that in 5 years. These are standard 210L steel drums (thats 55gal for yanks and 44 imperial? gal for us brits) and I go by the figure of 300kg each. 
Currently we use big homemade drum warming cabinets. These are big insulated cabinets that have electric radiators inside, linked up to a thermostat control. We stack pallets of 4 drums inside, each one takes 16 barrels at a time.

The problem is that they are hideously inefficient. These heaters work by convection energy transfer. This is the least efficient way of transfer. I want to make a system that transfers the energy by conduction or maybe induction. (I have ruled out radiation as too dangerous-dont wanna start a fire!). 

There are several types of off-the-shelf electrical drum heaters available on the market. Band heaters, blanket heaters, element heaters, heat pads, induction heaters and drum ovens are the main types. 
I dont have any experince with these. And would welcome anybodys thoughts or real experience.
The main problems that I can see are cost, energy use and what they do to the honey. If you have used any of these systems. how long does it take to fully melt a drum of totally crystalised honey? how many KWh's did that take? how often were you using these heaters? ours would probably be running everyday.
What happened to the honey? we make sure that none of our honey goes above 60C because we dont want to spoil it. Do you take the same consideration?
What about the heat transfer inside the drum? how do you get the heat into the crystalized mass in the middle with out over heating the melted part?

What about HMF? here in Europe we have to abide by strict rules on the level of HMF in honey sold as table honey. Do you have to do the same where you are? But as i hope to dramatically reduce the heating time this should bring our HMF levels down.

I am considering engineering our own soloution. We will probably be installing some kind of biofuel boiler so some kind of system that heats the barrels with water would be good. Possibly hot water baths that the barrels sit in or hot water elements that sink into the drums. Has anyone done something similar?

Something that i should proabably make clear... Most comercial honey packing facilities process large batches of drums which they partially melt and then drain into a jacketed tank or something similar. We are a speciality honey company-we pack a variety of different size honey batches from 1 drum to 10. So we need something more flexible. Thats why we are choosing to heat our honey inside the barrels.

So in a nut shell. What do you think would be the cheapest and most effiecient way to heat a large number of honey barrels?

Ok thats enough for now.

Thanks for your help


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## Ian (Jan 16, 2003)

The thing is your melting 50 drums per week. You need to be able to melt the honey quick and then cool the honey to a stable temperature for further processing. The way your doing it is basically the way its done. Perhaps more insulation in your room walls? Perhaps a more efficient boiler? Band heaters will not work for your volume. Water baths would probably cause you more trouble in the long run because of contamination concerns.

I do not know, just my thoughts


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## mgolden (Oct 26, 2011)

How about solar heat and a greenhouse structure, if you have the realestate? Tremendous amount of heat from the sun and use black north wall. May needs exhaust fans for temperature control!!!!


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## sqkcrk (Dec 10, 2005)

Nohoneyno,
Correct me if I am wrong. You put 16 barrels of crystalized honey in your cabinet at a time, liquify them, remove them, and then dump them? What if you set up a way of draining the liquid honey as the crystalized honey becomes liquid. Do you think that would speed up the process?

What you are doing now is liquifying the crystalized honey closest to the outside of the barrel first, which them liquifys the rest of the honey.

Can you stick a heat probe down into the honey and heat from the inside as well as the outside?

I think you need to be in communication w/ Honey Packers like Dutch Gold of Lancaster, Pennsylvania. Or their subsidiary in Littleton, New Hampshire, McClures' Honey and Maple Products.

Ted, here on beesource could direct you to Sioux Honey Co, Sioux City, Iowa.

Best of luck.


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## Nohoneyno (Jan 31, 2012)

mgolden said:


> How about solar heat and a greenhouse structure, if you have the realestate? Tremendous amount of heat from the sun and use black north wall. May needs exhaust fans for temperature control!!!!


good idea. When we design the ultimate energy efficient honey factory i'll include this. Not going to be for awhile tho at the moment we dont havethe space.
Not sure about exhaust fans tho. We are in the UK... it can get a little cloudy here.


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## Nohoneyno (Jan 31, 2012)

Thanks for your input Ian.

You say

"Band heaters will not work for your volume. "
Why not? have you used them? how long do they take to melt a barrel? if they could do it in a day we could have 7 running at a time. Maybe band heaters could run inside our cabinets. that proabably wont decrease our energy bills tho!

"Perhaps more insulation in your room walls? Perhaps a more efficient boiler?"
They are pretty well insulated but a lot of heat does escape when ever we take any out. At the moment there are electric heaters in there. I would like to install a new boiler system and maybe underfloor heating. That should make the system more efficient.

"Water baths would probably cause you more trouble in the long run because of contamination concerns"
Do you mean water getting inside the drums? or things growing in the water? we store several hundred drums outside in the rain...

"The way your doing it is basically the way its done"
I am hoping to draw on that experience and maybe find a new way. I dont think that other methods make energy consumption such a priority (especially in the US no offence to anyone). As the 21st century progresses fuel and electricity prices will just increase and increase. We want to get ahead of the curve. I am sick of handing out fistfulls of cash to those criminal energy companies! I dont know about where you are but they are pretty bad here. They do their best to rip you off as best as they can knowing full well there isnt much you can do about it. Dont get me started on fuel prices!

Ok rant over


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## sqkcrk (Dec 10, 2005)

Perhaps two or three barrel belts per barel run just warm enuf would do the trick.

This is really a hard thing to suggest solutions for not being able to see and experience all you have to deal with. Anything most of us would have to suggest would be tainted by our own knowledge and experience. And most of the Posters here have very little experience reliquifying even one barrel, let alone multiple barrels. So, I really think you need to investigate what others do at the level which you are working.

I hate to suggest solutions when I don't know enuf, but, I did wonder yesterday if you could set up a way to remove lids of crystallized barrels and turn them upside down over a heat source of some sort, stainless steel tubes w/ hot water or steam running thru them perhaps, so the honey will loosen and drain from the barrel as it liquifies.

To me, the problem w/ heating a barrel of honey to reliquify it is that the outside becomes liquid while the core remains solid. That solid core has to be liquified by the honey around itself. How do you keep from over heating some honey while getting all of it liquid?


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## beeware10 (Jul 25, 2010)

any large scale packer I have seen use a large room or box heated with steam pipes or heater.the barrels are placed so as they heat the honey drains to a tank. tnis tank can be below, pumped to another tank or in the basement below the hot room. the honey exits the hot room to be heated, filtered, and packaged. If honey were to be left in the barrel until entirely liquifyed it would be over heated. I have never seen a system heated with anything other than steam heaters.


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## Nohoneyno (Jan 31, 2012)

beeware10 said:


> any large scale packer I have seen use a large room or box heated with steam pipes or heater.the barrels are placed so as they heat the honey drains to a tank. tnis tank can be below, pumped to another tank or in the basement below the hot room. the honey exits the hot room to be heated, filtered, and packaged. If honey were to be left in the barrel until entirely liquifyed it would be over heated. I have never seen a system heated with anything other than steam heaters.


"I hate to suggest solutions when I don't know enuf, but, I did wonder yesterday if you could set up a way to remove lids of crystallized barrels and turn them upside down over a heat source of some sort, stainless steel tubes w/ hot water or steam running thru them perhaps, so the honey will loosen and drain from the barrel as it liquifies."

-sqksrk something like this is the system which most larger scale packers use.

Yeah i have looked at a couple of these. Our problem is our size-we are small honey packers really. Small packers trying to pack too much! The more common systems out there dont really work for our scale. We need to be able to do small batches with out having to clean out a mass of tanks and pipes everytime. And to be honest we just dont have the space-should have built a bigger shed!But i am considering a system like this, we would probably just need to build a new warehouse...
If the heaters worked fast anough it would be possible to pump the honey out as it melts i suppose. 

I had an idea to set up convection currents inside the barrel... if the drum was partially heated in a warm room (set much lower) first so that the outer layer is melted. Then heated from the bottom with those baseheaters. would the melted honey rise to the top, up the sides pushing the solid core down towards the heat at the bottom? do you think this would work?
or maybe a process that each barrel has the excess pumped off and then given a bloody good stiring?

OK new methods aside. *What do you think would be the best way to convert the existing warming cabinets to hot water heating?* underfloor heating with a fan?

"Anything most of us would have to suggest would be tainted by our own knowledge and experience."

That taint is what i came on here to find! dont worry you guys arent my only source of information but maybe you are the most experienced. There are some pretty big differences in scale between the UK bee industry and almost anywhere else!

Thanks again


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## Ian (Jan 16, 2003)

>>Band heaters will not work for your volume


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## Ian (Jan 16, 2003)

>>Band heaters will not work for your volume<<

The problem with band heaters is that they are for small scale use and can darken honey if not moved many times

>.Do you mean water getting inside the drums? or things growing in the water? we store several hundred drums outside in the rain...

ya, the rain could cause a problem too

>>Ok rant over 
ya I hear you. The way our packer does it is tip barrel over a heated grate and melts the honey as it comes out . Still requires alot of energy

But im not a packer, just a beekeeper. Hope my 2 cents counts


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## Joebee (Nov 28, 2011)

Has anyone ever tried a flat heat exchanger coil placed on top of the crytalized honey. As the honey melts the weight of the coil would keep it in contact with the solid core until it had worked its way to the bottom of the barrel. If the coil was made from pipe bent into a spiral shape it would fit well inside the barrel. Hot water circulated through the coil should be more energy efficient than heating an entire room, especially when heating small batches.


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## beeware10 (Jul 25, 2010)

I just remembered a small packer. they had stainless tanks surounded by a oak wood frame. they were mounted on 4 steel wheels about 10 inches in dia. each tank held two barrels and had a honey gate on the end. at the top of the wood frame were two pipes that went lengthwise. with a hoist one to two barrels were placed upside down on these pipes. they were in a hot room heated by steam to 150-160 degrees. there was a gutter in the middle of the floor made of stainless. the honey could stay in the tank or the gate opened above the gutter in the floor and the honey flowed below to a storage tank. with this system you could process 1 barrel up to any number depending on the room size. honey needs to flow away from the heat after being melted to maintain its quality.


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## ShadowHawk (Apr 17, 2011)

Were I to need to do it (and I will - far in the future) I would setup a simple solar water heating system. Here's a video that I found (Note - it's from Down Under - so the examples are for south of the equator) 

http://youtu.be/96WqrcK2OmM

You might be able to set it up with water drums in the "heating room" to act as a thermal battery to hold the warm/hot water. As it cools - it is recirculated back to the roof-top heat collector coils. These can be made with copper pipe, or PVC. I'd bet that copper would have a better thermal transfer form the collector to the water.

Here's another video on the thermal battery. A bit dry in the narration - but it's good info:

http://youtu.be/n90Y6Qwab_8

G'Luck!


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## Roland (Dec 14, 2008)

Post number 8 pretty much nailed it, except I prefer hot water, not steam. If you are serious about this, PM me, I have operated a system that used up to 70 drums a week, with many small batches. 

Crazy Roland


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## Michael Palmer (Dec 29, 2006)

I have an insulated hot room that will liquefy 50 drums in two weeks. There is foam insulation on the substrate with the concrete floor poured on top. There are radiant heat hoses in the concrete...twice as many as usual in a residential setting. Heats from bottom up.

I know a business that has a large tank with a grid of stainless hot water pipes on top. Open drums are tipped upside down on the grid. The honey gets hot, slided down throught the grid melting as it goes...I think McLure Honey and Maple in Littleton New Hampshire has it. You should contact Gordy or Chris at the plant. I'm sure they would help...good folks.


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## Nohoneyno (Jan 31, 2012)

Joebee said:


> Has anyone ever tried a flat heat exchanger coil placed on top of the crytalized honey. As the honey melts the weight of the coil would keep it in contact with the solid core until it had worked its way to the bottom of the barrel. If the coil was made from pipe bent into a spiral shape it would fit well inside the barrel. Hot water circulated through the coil should be more energy efficient than heating an entire room, especially when heating small batches.


I have been considering this idea joebee. It would take some fancy plumbing but it is doable! hows your engineering mathematics? how would you calculate the surface area needed to melt the honey in a certain time? 
what do ya reckon? just a coil of piping or something set into a heavy lump of metal (with a large surface area)?

I have been reconsidering the hot pipe drainage method. With some restructuring internally we could probably get a small one in. Does anyone have any figures of the watts used / drum or kilo for this method? or well any other method?

Ta


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## Daniel Y (Sep 12, 2011)

Right now your energy source is electric. You only need a different more efficient energy source. Changing electric radiators to hot water radiators and installing a solar water heater would do that. If you are in an area that has good solar exposure. The energy once it is installed is than free. So it is only the cost of the system and maintenance that is an issue. since your company already expects to pay for changes, and maintenance is going to happen anyway, they are a wash. Plus the solar heaters require very little maintenance. As far as the cabinets they would still operate on the same thermostats etc. except they would control a pump for the heated water and not a switch. Storage for the heated water can be an insulated box or can be buried under ground. It can be pressurized or not as long as you don't need temps above the boiling point of water. use anti freeze for the storage liquid and you can have even higher non pressurized temps.

You can figure designs will start at around $1000 USD and go up. way up depending on how fancy you need to get. If you build or purchase collectors and how much of the making in general you do. otherwise they are very expensive.

I was looking at one the other day that was very simple. you can build every component yourself and the storage tanks was a cube of about 4 feet or 64 cubic foot box. This is intended to supply hot water to a typical home. On sunny days this is continuous hot water. You might need to consult someone in order to calculate your maximum energy needs and design accordingly.


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