electric arch

[monterey]

Just wondered if any one has ever tried an electric arch before ? It would seem to me that it would solve a number of problems that every one is having with the increase cost of fuel oil and the cold spots that occur in a wood fired arch even with the blowers. Electric is very even and constant . Please let me know what your thoughts are .
I do know that you can not boil with the heaters in the finish pan and that they need to be used under it just like wood or oil ect. but tell me what you all think of this and I will go from there.
Thank for your time and input Roger

[TimJ]

I can't imagine electric being useful for boiling that much sap. The bills would be cost prohibitive.

Here is an example for heating:

http://www.chestnuthillchimney.com/Comparison%20of%20Oil,%20Wood,%20Pellet,%20Gas%20a nd%20Electricity%20Costs.htm


Electricity has the worst value of cost per BTU.

Here is another one

http://nepacrossroads.com/fuel-comparison-calculator.php

Even with higher fuel costs, oil and wood would be far cheaper than boiling sap with electricity.

[maple flats]

To have any electric of any larger size you would need an industrial grid connection. Then the energy will still cost you more than the value of the syrup you make. The only way is if you get free electric by way of excess net metered green energy and even then it might be a bad deal.

[monterey]

Well thanks for for info. How ever there is on problem in the web sits that you sent me .You are or they are concerned with btu output and trying to match btu output in electric is not the correct way of doing things.And yes you can not do this on a house hold 220 vac single faze current as you will not have the power you need to create the heat needed .
Another factor that you need to think about is there is no chimney ,that means no heat going up the stack that you must replace with more fuel below.The only thing that you need to concern yourself with is how to stop the heat from going down so you can push it up so there is more boiling and that is a hard task.

By know you might get the hint that I have tried this and you are right I have for 2 years now and I boil around 10 to 12 gallons of sap per hour in a continuous flow pan that I built .I also built the arch that contains a 18000 wot heater bank that uses 480vac 3 phase. It runs me about .18 per hour to run and I am heating at a constant 1600-1800 degrees.
The biggest problem that I have yet to over come is to contain the heat and force it up into the pan .So far I have used 2 layers of fire brick and that helps but I need more. I am going to try some 2800 degree blanket next and even some foundry cement to help hold the heat in.
In the works for the next year is a sap pan 2 x5 with 22500 wot in sap heaters to help evaporate .This pan is flat bottom and it to will be set up as a cross flow and also this pan will have a temperature setting thermostat to keep the sap at just under boiling witch will make it even cheaper to run. Have any questions feel free to ask I have been working on this for 2 1/2 years now and it gets better every season .
Thanks for your input and time Roger

[sirsapsalot]

Here is some info on electric evaporators. http://www.sugarbush.info/forums/showthread.php?t=632&highlight=electric+evaporator

[Michael Greer]

This is interesting Monterey. Let us know how your experiments go. In general, we're always open to a different idea, and somebody has to try it out, don't they?
I have an electric tea kettle that's really fast. The coils are soldered right to the bottom of the vessel, and there's insulation below that to protect the countertop.
Many sugarmaker are put off by the idea of any kind of fuel cost, and regard firewood as a free source from the woodland process. That said, we know firewood isn't really free don't we? There is also some recognition of one's "carbon footprint" and electricity from coal is very bad.

[monterey]

This is interesting Monterey. Let us know how your experiments go. In general, we're always open to a different idea, and somebody has to try it out, don't they?
I have an electric tea kettle that's really fast. The coils are soldered right to the bottom of the vessel, and there's insulation below that to protect the countertop.
Many sugarmaker are put off by the idea of any kind of fuel cost, and regard firewood as a free source from the woodland process. That said, we know firewood isn't really free don't we? There is also some recognition of one's "carbon footprint" and electricity from coal is very bad.

Well if we look at the carbon foot print (something that I don't know how to figure out) it would seem to me that any heat going up the stack is a total wast of not only heat but lost fuel.
If one looks at how we are trying to get better and more out of our fuel weather it be wood ,oil, gas I wish that one would take the time to think out of the bun and think of ways to use there heat up so there no stack temps over 180-200 that is when I came up with my unit. There is no stack that is a good thing .
The other thing we need to do is to increase the area of the open top pan and let the sap evap faster not so much the boiling of the sap but the evap of it.
Yes I do agree that the new deeper flues help with the boiling ,but i think we should us longer or put a another one behind it to help cool the stack temp .
I did a little experiment this year with a 2 x 4 pan and gas to see if i could use less fuel and not compromise my boiling and I can tell you that if I used 1 5th the gas and never slowed down just by increasing the area of evap, that is why my sap pan is not going to boil less energy and that is a good thing
Thanks once more for you input and time Roger

[Diesel Pro]

A large induction type unit with a magnetic SS pan would be interesting, but I'm not sure about sizing of the long term durability. I do know that my induction cooktop is VERY fast to boil, byut can also run into "time out" issues either due to heat or a system timer to protect against forgotten pots.

[TimJ]

Given my two syruping locations (Long Island NY (backyard hobby)and near BTV VT (very very very small-time commercial)) and what I know about fuel oil, wood and electric prices it seems hard to imagine that using electric power to boil all that sap would be cost-effective.

I am not a scientist or an engineer. I do understand a lot of heat is lost when making syrup. But as something a bit more than a hobbyist I can't ignore the economic realities and practical aspect of boiling all that sap/evaporating all that water.

I hope we do get more options in the future. My hat is off to those that tinker and experiment with alternatives. Keep the innovations coming!

Maybe cold fusion/Mr. fusion is on the horizon. Until then I'll be splitting and burning wood.

[monterey]

Hay diesel pro there could be time out issues with the heater if it is not made with the right material .You can get SS or Incoloy that is a alloy that will with stand much higher temps and so far as held up very good . The engineer has told me to but a high limit safety shut off in to turn off the unit as it will go wild however I have no problem yet and a hi temp is not cheep so we will wing it for now and push them to the limit.
The other thing that some of you need to know is you can not put the heaters in the finish pan or you will have a big mess the syrup will burn to the heaters (not good) so don't try it.However in your sap pan no problem and you can insulate the pan and make it more user friendly on you bill.
Thanks for the feed back Roger

[PerryW]

.I also built the arch that contains a 18000 wot heater bank that uses 480vac 3 phase. It runs me about .18 per hour to run and I am heating at a constant 1600-1800 degrees.
r

an 18,000 watt load would draw 18 Kilowatt Hours (Kwh) for each hour. Isn't that a lot more than $0.18 per hour?

I would think you would need to RO the sap up to a decent percentage before it would become practical at my electric rates.

[monterey]

Well as far the math on your khw your numbers could be correct ,how ever on 480vac and a 15 amp draw to the 18000 watt heater you would need to amps x volts witch is less than 18000 khw on the total draw .
I can tell that you are set in your ways and that is fine, but my system worked very well and I did not spend count less hours splitting wood (that I am not getting payed for )or buying 3.00 a gallon or more on oil . It is very clean and noise free and my back nor my check book is sore at the end of the season.
I came on here to tell you my findings so that maybe I could find a person or group of people that think out side the bun and move forward and not stuck in a rut of back pain and oil bills.
If I get my next ban done for the next season I will tell you how it went.

Thanks for the feed back men and your time Roger

[Diesel Pro]

Very few have access to 3 phase 480...


At a buck a gallon propane is not a bad idea.

[monterey]

If I could get propane for a buck a gallon I would do that in a hart beat .But around here propane is almost as bad as gas for your car. But if you look at the btu output of oil and than the lower output of propane the price per btu hour and the high price of oil propane is the way to go and you will save money.I have customers that were heating there shops with oil and now are on propane to save money .
Maybe I should say the heck with this an start working on a corn cob stoker auto feed system at least then my fuel would be free so to speak and that would make more sense to all you wood burning people out there.
Thanks once more for your input Roger

[sandman6921]

If you look at cost per BTU -- Coal is usually the cheapest!

[monterey]

That it is and I have looked at that. That is when I came up with the thought of using corn cobs. I been looking for a old coal stoker for a couple of years now ,found some on ebay but the shipping would kill me .Looked at several on u-tube to see what made the tick and and thought I would start from scratch .There really isn't that much to them my main concern is the auger in the old days they were cast iron I would make mine out of steel.
Thanks for the feed back Roger

[Johnny Yooper]

interesting thread; I actually finish on an electric range I snagged for free from the salvage pile at a local hardware store, stove looked new and wondered why someone traded it in; took it home not knowing if any of the stove top elements worked, but plugged it into 240VAC supply and low and behold, they all work fine. With two large and two small stove top elements, I'm guessing I have about 2(2250watts) + 2(1200watts) = 4650 total watts and if I finish boil a batch for 2 hours and at my electric rate of $0.12061 kW-hr, that costs me just over one dollar. My finish pan is rectangular and is the perfect size to completely catch all four elements, I address hot spots by adjusting the two large elements and stirring during the process, which still leaves one hand to hold 12 oz of your favorite beverage. This method works very well for me. Not sure how cost effective it'd be for doing the major boiling unless you either get it or produce it for very very cheap. As someone mentioned though, most homes aren't set up for three phase, but if you are using three phase electric power, remember to use the square root of three in your calculations (for a resistive load, 3 ph Watts=square root of 3 x volts x amps). It's all about what works best for you; I do the main boiling on a wood fired arch, I enjoy (so far) cutting firewood and getting some exercise and the supply is close at hand and culling out the junk wood in the sugarbush is a plus. I'm amazed at the variety of ideas and plans on this site and I thank you all for contributing, we all learn from each other. Good luck for the rest of the season for those that are still boiling!

[kytepc]

I have read that stainless steel is a poor conductor of heat. That is why stainless pots bottoms are cladded with aluminium or copper. Commercial electric range companies have mild steel plates that bolt to the elements to transfer heat better to stainless pots.
I know that hot food prep carts will boil water under the food inserts pans. The elements are long and sometimes crimped to plates with white insulation under the element. Electric is 100% heat transfer is the key

[not_for_sale]

I think there are two things that I don't understand correctly here:

1. Electric heat: You are talking about tube heaters in the sap? Stainless tube heaters similar to the heaters used in a sauna stove?

2. 480-3 phase is not cheaper per kwh than 220 single phase! if you have an 18 kw heating element, and you are with Consumers Power in Michigan it will cost you 18x12 cents ($2.16) on a residential contract and about $3.00 on a commercial contract per hr. Its not a big deal to get 18 kw out of a residential 100 Amp service. We are talking 75 amps - whole house electric tankless uses 150 amps.

3. One kw of electricity has roughly 3400 btu. So you are feeding 61000 btu per hr into your pan. Efficiency would be near 100 % since your heater is in the sap and your pan is insulated.

4. One pound of wood (dry) has roughly 6900 btu. However, you are losing efficiency - heat out the stack. transfer to the sap, and insulation of the arch. If that efficiency is 50 percent, you are producing the same btu as roughly 35 lbs of wood that are used for actual evaporation.

5. If your sap or concentrate is 40 F you need 172 btu per lbs of sap to get it to 212, plus the evaporation energy for a total of roughly 1140 btu/lbs.

6. In total is the theoretical capacity of a 61000 BTU heater to evaporate 40 F sap or concentrate is 7.1 Gallons per hr at 100% efficiency. Of course, a steam away would be very called for here. Since that would use part of the evaporation energy.

It doesn't matter what energy you use to evaporate. Usually in Michigan an electrical BTU cost 5 times the money a natural gas BTU costs, and if you pay $75 a cord for wood its about half the cost of natural gas. Of course, transfer efficiency is what needs to be looked at.

[monterey]

thanks for the info there.
I know that on paper it all looks bad how ever it works very well and is not as hard on the check book as one might think.One thing that you said and is the key to why this works so well is that I have no wast heat going up the stack all of my heat is going into the boiling of the sap.
Now one thing that I feel you missed is that you can not finish with the heaters in the syrup as it will make a mess of things so my syrup pan sits on top of the heater bank .This year up at the maple show I talked to a person that told me what to use for the problem of stopping the heat from going down and we will be doing that before next year, that in it self will increase my boiling rate .
The next thing that I would like to address is you do not need to boil to get evaporation so my sap pan will be set up with heaters in the sap to start sweating the sap as you would in your flue pan how ever I will be doing it at a max temp of 200 and it will be controlled with a thermostat to help save money as well .
If I can locate a high temp thermostat I will be putting one of those in my heater bank under my finish pan to help save money also.
I got a 600 degree but that is to cold I feel that I need a 1200-1500 min.
I hope to put a meter on the shack next year so I can tell you all what it ran me to boil my syrup and then all of you will know that this is not a bad way to go as I am way to busy to cut cord after cord of wood .
Thanks once aging for all the input Roger

[not_for_sale]

I am not sure what you are talking about when you say high temp thermostat. I assume you are talking about an aqua stat.

http://www.amazon.com/gp/product/B0026NDC5O/ref=as_li_tf_tl?ie=UTF8&camp=211189&creative=373489&creativeASIN=B0026NDC5O&link_code=as3&tag=mapletrader-20

[monterey]

A high temp thermostat it works just like the one in your house but it is for high temps 1200 to 1500 degrees .I have found a 600 degree however that is not hot enough to boil . I know it boils at 212 however it dose not work very well at all at a controlled temp of only 600 degrees.
I was told to get a 1200 to 1500 degree thermostat with a 1600 to 1700 degree over limit stat to shut the unit down if thing went wrong ,but so far I have not had a problem.
The 600 worked good and if I can locate a higher temp that I am looking for it will save me a fair amount of money as it will cycle the heater on and off.
Thanks for the input Roger

[MapleMark753]

If I remember my Thermodynamics lessons well.... I think the gist of what I'm thinking is that warmed air is what rises, and heat radiates from an object equally in every direction. So, insulation is required to retain heat to maintain a boil, but what about adding reflective material angled from the electric heat source to the pan bottom? Polished stainless may do that ok. Also, since heat (radiation) can reflect off of objects, the material on the bottom of your pan may be critical. Flat black high temp paint, or a flat black ceramic coating would seem to be something that would be desirable, to absorb the electric radiated heat, not reflect it like lots of metallic substances do well. Just a thought. Good luck, take care, Mark.

[not_for_sale]

Roger,

I don't really get what you are trying to do. If you aren't placing your heater in the sap but under the pan your efficiency isn't 100 percent. Far from it.

If you are placing your heater in the sap, measuring liquid temperature will be more effective than measuring the surface temperature of the heating element. The liquid sap won't be 600 degrees.

[monterey]

We will be doing it both ways the sap or what you call it the flue pan (with out flues in this case) will have the heaters directly in the sap and I will keep the sap at 200 or so that way I get good evaporation with no boiling. I will maintain the temp with a thermostat that I all ready have and works very well.
The syrup pan however the heaters must be under the pan as you do not want the heaters in the syrup as you will have a mess real fast.
The thermostat for that needs to be one that will turn the heaters on and off at 1200 to 1500 degrees to get a nice even boil .

I have wondered about sandblasting the bottom of the pan to make the surface a flat finish as to the smooth and shine e one I now have as I thought it might help to absorb the heat in to it .
Thanks for your input Roger

[not_for_sale]

Roger,

The reason you need a flue plan is because of the heat transfer. You don't need a flue pan if the heater is directly in it.

As far as the finisher goes: you can still regulate on the liquid temperature. Just sandwich the heater under the pan, and insulate below with arch board and high temp foam insulation.

Shiny does not improve transfer. Actually, black does. A shiny surface will reflect 97-98% of the radiant heat.

Evaporation only happens if the liquid gets moved from liquid to gaseous state. With water that happens at 212 F. There is actually water at 212 and steam at 212. The difference is 950 btu / lbs of energy.

Your evaporation rate will slow dramatically if you don't heat the liquid to 212.

Joe

[monterey]

Thanks Joe,
I do agree with you on getting the bottom of my heater bank insulated to stop the heat loss out the bottom but as far as getting no evaporation on sap that is not boiling I do not as I did a little fooling around with my old set when I started to get behind and I must say I could not believe how well it worked.
What I did was hook up my old pan to a drip valve and regulated the sap flow into the pan ,the kicker was I never let the sap get into a nice boil all I did was to get it hot and keep it there .
2 years ago I used to use 1 100 pound cylinder every 2 days this year doing it like this to sweeten up the sap it lasted almost 6 days and I did not need to get any more gas .
I was surprised that it worked so well that is why I am going to keep the temp lower in my sap pan next year.
Thanks for the feed back Joe . Roger

[RileySugarbush]

Certainly 200 degree sap evaporates, heck, room temperature sap evaporates, but neither at a very satisfying rate. I wonder if you looked at gallons of water evaporated per 100 lbs of propane in both situations?

What kind of an overall evaporation rate are you looking for, Roger?

[PerryW]

I wonder if you could put the heating element directly in the sap to avoid worrying about heat conduction through the metal of the pans? I know they make immersion electric heaters to boil water for coffee and to keep water for cattle ice-free.

[monterey]

Evaporation rate is something we all look at and I want to get all I can just like the next guy.However using electric one needs to look at how to do this in a hole new light .It is not how can I get this sap to boil that is the easy part .One needs to look at how to do it with spending the least amount of money and it what I have found out so far the larger the area or pan size and just getting the sap up to 180 -200 I can move a lot of sap through my set up will little money any not making my hobby into a full time job of cutting wood .
Next year I hope to be evaporating around 25-30 gal an hour and for a 24 x 9 with no wood no steam away just flip the switch and go that would be fab.
Thanks for all your input guys Roger

[wiam]

I can see that what your doing will work, but your syrup could end up very dark from extended cooking time

[RileySugarbush]

OK, I know what you are looking to do now.

Summarized: All electric evaporator where minimum energy cost is the prime goal. Production rate is secondary.

Right?

What you are proposing is to use radiant electric heat on the bottom of a flat syrup pan. Basically a toaster. Increase the heat transfer with a very thin layer of soot from an acetylene torch.

Your sap pan is acting like a big steam away only the heat source is electric instead of waste steam energy. You can estimate the evaporation rate of nonboiling fluids. Check out these methods for rough numbers:

(http://www.air-dispersion.com/usource.html#Non-Boiling Liquid Pool)http://www.air-dispersion.com/usource.html#Non-Boiling Liquid Pool

Those equations assume a flat top surface exposed to air.

Just like in a steam away, the evaporation rate is greatly enhanced by exposing the fluid to dry turbulent air. The best way to do that is by introducing dry air in pipes with a series of small holes submerged in the sap. This increases the effective surface are, keeps boundary layers from forming and mixes the sap all at once. A cheap source of submersible elements for that pan are water heater elements. You might be able to use a water heater thermostat too, but you will need to mess with it to get to 200°F.

I think a 2x5 steamaway with a 1hp blower adds about 25 gpm of evaporating rate, so it seems that is the size you are shooting for.

[monterey]

Thanks for the help there on the dry air input I will be looking into that . As far as the elements I had some made to fit my pan.
Thanks once more that is a big help Roger