e-Vaporator

[Fyreaway]

For anyone wondering if an electric evaporator is a valid option, the answer is yes.

11620

This is my electric fired evaporator version 2.0. For a small hobby producer this just might be something to kick around. With an evap rate of over 3gph it makes keeping up with less than 20 taps quite doable.

The kettle is fired by a 4500 watt stainless steel water heater element running at 240v. It's about 18" square and 12" deep and will hold a smidge over 6 gallons of liquid gold. Power is fed through a PID controller and relay (hence the heat sink) giving complete control of every aspect of the boiling process.

Here's a short list of why this thing works for me;
* Never run out of fuel. (Don't have to haul 20# cylinders of electricity.)
* It's cheaper than propane. (That should get some discussion going!)
* Does not need constant attention. (I can get work done around the house and have a meal with the family.)
* Instant on and off. (If I have to leave I just shut off the power, throw a cover on and go.)
* Filter on the fly. (As the sap darkens up I draw off into a bucket with a syrup filter and then dump it back into the kettle.)
* It's a batch boiler so I get a bit darker, richer syrup. (Always a win in my household.)
* At finishing time the PID lets me slow things down to a more controllable level.
* After final filtering the syrup goes back into the kettle and can be held at any temp for bottling.
* Quite portable. (On nice days I set up outside and on the other days I work in the back room with a fan blowing the steam out.)
* It's weird and it's different and I made it myself!

This is the third year boiling with only electricity. Version 1.0 was half a plastic barrel and no electronic controls. It worked as proof of concept so I had the stainless kettle made and stepped up to what I have now. Questions...?

Thanks for letting me share. ~Eric

[Dennis H.]

If the heating element is in the sap/syrup how much junk does the heating element get built up on it?

Neat concept.

[Jeff S]

Eric ,

I would like to see more of the details of your evaporator for example is your heating element directly exposed to the sap you are boiling. Have you considered insulating the sides at all ? Would like to hear your thought about shape of you evaporator, noticed its more narrow at bottom as opposed to just a rectangular box.

As an experiment couple of years ago I made 1 gallon of syrup with an electric roaster with a Kill A Watt to monitor electricity use, the end result was that it cost just under $20 to boil off 40 gallons of sap, how does yours compare. Great job by the way.

Jeff

[Cedar Eater]

It looks easily maintainable. How much did it cost for the custom tank?

[Fyreaway]

If the heating element is in the sap/syrup how much junk does the heating element get built up on it?

The element gets junk built up to a point where daily cleaning is necessary. An hour long soak in warm vinegar and then a few minutes at a rolling boil gets it cleaned up like new. Almost no scrubbing needed.

[Fyreaway]

Eric ,

I would like to see more of the details of your evaporator for example is your heating element directly exposed to the sap you are boiling. Have you considered insulating the sides at all ? Would like to hear your thought about shape of you evaporator, noticed its more narrow at bottom as opposed to just a rectangular box.

Jeff,
I'll have some more pictures after a cleanup. Version 3.0 will be in an insulated cradle and the drain valve will be bigger. The shape of the box was intended to make a complete drain possible without lifting the pan at all. It works really well. There is less than a tablespoon of liquid left in the pot. Without any real scientific research I thought that the triangular shape would allow heat transfer to the surface and create a bit of circulation in the sap. As it is, the heavy bits fall out of suspension and rest on the bottom beneath the heating element so there's no burning of nasties.

[Fyreaway]

It looks easily maintainable. How much did it cost for the custom tank?

I think I gave the welding shop about $200 for the tank. They used stock that was left over from another project so I had very little input into the material. It's plenty hardy but I would probably go with thicker stock next time. As for maintenance, it fits in the slop sink and other than spraying water all over the back room it cleans up very easily. Sometimes it gets a quick wipe down and other times it gets a bit o' polish. A quick soak in hot vinegar cleans the heating element when there's sap waiting and no time for a tear down.

[Jeff S]

Eric,

If your unit will evaporate at 3+ gallons an hour, I could make a gallon of syrup for around $8 a gallon that's not bad for not having to mess with wood.
After all the fees and charges that go with it I figure I pay $.14 a kilowatt to boil approx. 40 gallons of sap.
40 gallon/3 gallons per hour =13.33 hours
13.33hours X 4.5 KW = 60KW
60KW @ $.14 = $8.40 per gallon

Cant wait to see more details
Jeff

[WESTVIRGINIAMAPLER]

An electric stove with a stainless pan on all 4 burners would work good too and way cheaper than propane.

[Fyreaway]

Jeff,
Glad to see I used the same numbers you did. My last electric bill was about $0.09/kWh so I think I'm even farther ahead. The cost of propane is pretty close but the efficiency of the electric heater is real close to 100% where propane is doing well at 60%. I still think that the best part is that NYSEG is very happy to bring my fuel right to my house and they hardly ever run out in the middle of a batch.

[Fyreaway]

Here's the heating element in the kettle. 4500 watt running at 240v. The nut is stainless with an o-ring that came from a home brewing supplier.
11635

Here you can see the drain valve and the temp probe.
11636


Electrical connection on the outside. There's a piece of PVC pipe with a cap that the wire runs through to protect from an accidental defibrillation. The ground wire runs to a grounding clip from a metal work box. She sits in a round cradle from the first version that was half a plastic barrel.
11637

The brains. This PID controller lets me run based on temperature or a percentage of total available power. As the boil nears the end I can dial back the boil to any percentage of capacity to make it a bit less of a panic situation and nearly eliminate boil overs.
11638

[Cedar Eater]

A suggestion for your next model. Add a switch so you can change the voltage on the heating element to 110 for when you are only heating to bottle. It will only use 1/4 of the power, but more importantly, the heating element won't cake up as badly because the surface temp will be much lower.

[Fyreaway]

Add a switch so you can change the voltage on the heating element to 110 for when you are only heating to bottle.

Cedar, that's a great idea. I've already planned a second power outlet on the control box for 110v so I can use a slow cooker for sous vide cooking. Using the switch to change voltage for the big outlet would be very helpful. By the way - this thing has cooked some pretty awesome steaks to exactly mid-rare, ready for a quick sear on the grill.

[Jeff S]

Eric,

Nice pictures, I'm thinking your 3.0 version with insulated sides will allow for an even more efficient boil.

At $.09 a Killowatt your all ready making a gallon for under $6 ,that's hard to beat.

You say the top is about 18" x 18",this seems like a nice size for the home hobbiest.

Again Great Job!


Jeff

[Jeff S]

An electric stove with a stainless pan on all 4 burners would work good too and way cheaper than propane.

Brandon,

I believe your right, I recently pick up a used apartment size electric stove to put in my garage for summer time canning.

Jeff

[Dennis H.]

Induction heating???
Now that would be cool.

[Clinkis]

Wow, if you can make a gallon of syrup for $6 that's great! That's about what I'm getting on my propane evaporator but I have to RO a lot of water away first to get it. If I was a smaller hobbiest this would make a lot more sense then propane or even wood. Did you notice any difference if your syrup from traditional boiling methods?

[Fyreaway]

Did you notice any difference if your syrup from traditional boiling methods?

Because it's a batch boil process the syrup is usually a bit darker. I prefer it that way so it's a happy outcome. I actually break all the rules of making syrup and add water at the end and boil more to get a richer flavor. Cooking a bit longer doesn't change the density but caramelizes the sugars a bit more. Because I don't sell anything I have to answer only to my pancakes.

[Sugarmaker]

Very nice job on the electric evaporator!
You did a great job breaking the rules! A mini RO would work great with one of these too!
Regards,
Chris

[Cedar Eater]

Another suggestion. Makers of biodiesel who use an electric water heater paint Liquid Electrical Tape (http://www.walmart.com/ip/16351039?wmlspartner=wlpa&adid=22222222227009482987&wl0=&wl1=g&wl2=c&wl3=42975821912&wl4=&wl5=pla&wl6=81467944112&veh=sem) on the connections to the heating element to waterproof and oilproof them. It comes in a can with a brush and it sets up really well. You can cut it away with a knife when you need to replace an element.

[Cedar Eater]

I have an old stainless steel kitchen sink that's been lying around for a while. I think maybe I can get a hole cut in it for a water heater element and find some way to plug the big drain hole in the bottom. It would be a poor man's version of your eVaporator, but if I can add a valve to the drain hole, it might be almost as useful. I wouldn't expect 3 gph, but it looks about the size of a full size 6" steam table pan, so maybe 2 gph.

[Newbie18]

Just down the road in Warkworth and started a few trees this year. Just using a home made barrel evaporator but would like to improve. Made about 6 gallons this year

[saphound]

Holy crap! I spent 40 dollars in propane to make a gallon and a half. Are you going to market these things, Eric?

[Fyreaway]

I have an old stainless steel kitchen sink...

This is brilliant! Honestly never thought of using a sink. So many possibilities, makes my head spin. I really like the bottom drain concept. You should be able to see the sugar sand building up and then drain a bit through a filter and dump back and never lose the boil. Get a double basin unit and use one side for finishing at a reduced boil. Even if you want to go with new equipment you should be able to set up a whole system with one trip to Lowe's. One other thing I forgot to mention; the heating element should be Ultra Low Watt Density. The longer heating tube spreads the heat over a larger area so the burning is greatly reduced.

[Fyreaway]

Are you going to market these things, Eric?

I would love to market these things but I'm already having more fun with the crowd sourcing of ideas and improvements. Posting on this forum makes the concept more available to more people who are more inclined to offer suggestions for improvement. Perhaps somebody will seize on the idea and make something available commercially and I'll have a wee giggle when I see one in a catalog. As a tiny little hobby producer it's more about finding ways to make the fun more available to more people. I can imagine an electric evaporator being used on an apartment balcony.

[Cedar Eater]

One other thing I forgot to mention; the heating element should be Ultra Low Watt Density. The longer heating tube spreads the heat over a larger area so the burning is greatly reduced.

Thanks for that. I was wondering whether I could get enough heat at 120 VAC to boil a sinkful.

[jrgagne99]

I would love to market these things but I'm already having more fun with the crowd sourcing of ideas and improvements. Posting on this forum makes the concept more available to more people who are more inclined to offer suggestions for improvement. Perhaps somebody will seize on the idea and make something available commercially and I'll have a wee giggle when I see one in a catalog. As a tiny little hobby producer it's more about finding ways to make the fun more available to more people. I can imagine an electric evaporator being used on an apartment balcony.

Those were my exact thoughts when I was working on the small-scale RO system 5 or 6 years ago.

[Fyreaway]

I was wondering whether I could get enough heat at 120 VAC to boil a sinkful.

There's really two different questions here; 1. how much energy is enough 2. how much energy is available.

We really don't need to boil the sap to evaporate the water. If the pot is steaming you're making syrup. Realistically the faster boil will reduce the sap faster. Something about BTU input and bubbling and surface tension and fairy dust that I don't fully understand but experience shows that more BTU input will make the water go away faster. One of my early experiments was a 6" hotel pan with two heating elements. I didn't have access to a 240v outlet so I used two 120v elements and plugged each into a separate outlet on different circuits. Actually this worked too well. I was in the kitchen and the window box fan couldn't get rid of the steam fast enough. After replacing the wallpaper I decided to try something different. I think a single element in a vat the size of a sink might struggle to keep a full rolling boil. So... either figure out how to use 240v or try the twin element thing. A word of caution; I have no idea what I'm doing so anything you hook up or plug in should be carefully thought out and probably looked at by someone who understands the concept of AC power. Offer your neighbor/electrician some fine homemade syrup for their time and we'll all rest easier.

[Cedar Eater]

A word of caution; I have no idea what I'm doing so anything you hook up or plug in should be carefully thought out and probably looked at by someone who understands the concept of AC power. Offer your neighbor/electrician some fine homemade syrup for their time and we'll all rest easier.

No problem there. The first few years of my career were spent as a power systems engineer. Everything from 5 VDC to 12K VAC. I know more than enough to get myself in big trouble. :D

I used a water heater to make biodiesel, and that was a flammable liquid, so as long as I ground the sink and use thick enough lead wires, I'll be able to safely kluge this in. I have a 240 VAC 30A feed to my spa that I can rewire for this purpose if I have to, but I hope I can just plug into an outdoor 120 VAC receptacle so I can have this on my deck where my propane burners are. I could conceivably ramp up to 5 gph by running everything at once. I think I'll just manually control the eVaporator at first. I think I'll put the sink in a cardboard box and fill the space between with foam insulation. That will help make sure that the heat is going into the liquid before going out into the air.

[VTmaplehobby]

Something about BTU input and bubbling and surface tension and fairy dust that I don't fully understand but experience shows that more BTU input will make the water go away faster.

Where can I get the aforementioned "fairy dust" I feel like I have exhausted all other options? :lol:

[Fyreaway]

...I know more than enough to get myself in big trouble.

The wiring is pretty straight forward. The challenge I had was with the introduction of the PID controller. I've never used or seen one so there was a bit of research to be done. I learned a bunch from the biodiesel and the home brewing communities. If your spa has a plug, or can be wired for one, using that circuit should be just right. I use a clothes dryer receptacle and hot swap the plugs as needed. Insulating the pot should be a big help. I'll be doing that next year.

[Fyreaway]

Where can I get the aforementioned "fairy dust"

Fairy dust is not generally available at retail. One must simply... believe.

[saphound]

I would love to market these things but I'm already having more fun with the crowd sourcing of ideas and improvements. Posting on this forum makes the concept more available to more people who are more inclined to offer suggestions for improvement. Perhaps somebody will seize on the idea and make something available commercially and I'll have a wee giggle when I see one in a catalog. As a tiny little hobby producer it's more about finding ways to make the fun more available to more people. I can imagine an electric evaporator being used on an apartment balcony.

Ok, just wondering. I could be in Cortland in less than an hour if you move on to 3.0 or 4.0 models and want to sell any of the earlier ones..or would it just be upgrades to what you have now?

[Fyreaway]

...or would it just be upgrades to what you have now?

I'll most likely use the same kettle next year. I've got some improvements that I can make without getting into fabrication of a new boiler. Metal work is all foreign to me so I'm a bit limited in how much I can change. If I could make this out of wood it would be changed weekly.

[saphound]

I was just thinking about your hotel pan with the twin 120 elements. Did you ever try it with just one of them plugged in? Hotel pans are cheap. What do the elements cost roughly, and the PID controller?

[Cedar Eater]

Some stats on my stainless steel sink. It's 16 X 21 X 7 inches, minus something, maybe 10 - 20 % for rounded corners (which are easy to clean). So if I did my calculations correctly, it holds between 8 and 10 gallons and has a surface area of approximately 2 sqft. That could actually be a very nice kettle.

[Fyreaway]

I was just thinking about your hotel pan with the twin 120 elements

The twin 120s; sounds like a NASCAR event or a fishing boat! I did try using just one and was disappointed in the result. It made heat and got the pot steaming but I never got a real good boil. The biggest problem with a 120v heater is you're limited (mostly) to 1500 watts. Running two you'll get a good boil but the nuisance of running two power cords and making sure they're on separate circuits can be a challenge. The heating elements can be found for about $30. This is where some online shopping will be helpful. Finding an all stainless element locally is a bit tough. I found the best place for suggestions and help was at one of many home brewing forums. I think I have about $100 in the controller box. The project box houses the PID, the solid state relay, and the heat sink. There's also the electrical connectors so I think $100 all in is pretty close. I waited too long before jumping into the control issue. Had I known how much easier it made the whole process I would have spent the money much sooner. I guess my advice to someone wanting to try this out is to go as cheap as possible for the first try. Get some stuff at the hardware store and boil some water to see what happens. If it feels good and seems to work for you don't be afraid to spend a bit o' cash to make it all stainless and easily controlled.

[Fyreaway]

Some stats on my stainless steel sink...

I like the sink idea more all the time. One thing I like about my franken-boiler is that I see very little difference in evap rate based on depth of sap. I usually run it full to the top just to give myself a bit of cushion in case I accidentally take a nap while I'm boiling. (I admit it. It has happened.) The other reason for running the sap at the top is my pretend scientific knowledge. Apparently the transition from liquid to gas takes place right at the surface of the liquid. If I keep a fan blowing the steam away I keep fresh dry air at that interface. Don't know if that's really the reason but I notice a bit faster evap with fan running. Another thing to ponder; I notice very little temperature difference of the sap within the boiler. Sometimes I just like to mess around with things. The PID can be set to display temperature in tenths of degrees. I have to use that setting to see any difference in the temp of the sap. There has to be a limit to how much fluid a single element can heat and how far from the element that heat conducts. Surface area will be a huge factor in evap rate and finding that sweet spot ( so to speak) will be a challenge for someone more smarter than me.

[saphound]

Excuse my ignorance of all things electric, but why do you need to run each of the 120's on separate circuits? You'd blow the breaker? And did you ever get a pic of frankin-boiler in action? I'd love to see the boil if you have one.

[Jeff S]

P = IE or I = P/E or E = P/I

P - power measured in watts
I - current measured in amps
E - voltage measured in volts

If you are using 120 volts and a 1500 watt element I = P/E --- I= 1500/120 --- I = 12.5 amps --- 2 elements would be 25 amps

120 volt circuits use either 14/2 wire that is rated for 15 amps or 12/2 wire that is rated for 20 amps both of which are too small to handle the 25 amp load.

[saphound]

Thanks Jeff.:cool:

[67HEAVEN]

Eric,

I find your design and experimentation fascinating. Well done.

I hope there's more discussion in this thread. :D

[Fyreaway]

...did you ever get a pic of frankin-boiler in action? I'd love to see the boil if you have one.

Today's first batch.

11687

[Flat Lander Sugaring]

P = IE or I = P/E or E = P/I

P - power measured in watts
I - current measured in amps
E - voltage measured in volts

If you are using 120 volts and a 1500 watt element I = P/E --- I= 1500/120 --- I = 12.5 amps --- 2 elements would be 25 amps

120 volt circuits use either 14/2 wire that is rated for 15 amps or 12/2 wire that is rated for 20 amps both of which are too small to handle the 25 amp load.

AWG 12 good for 20A derate at 25A melts in half at 56A

[saphound]

Today's first batch.

11687

Awesome! Thanks Eric...now skim off that foam, lol.

[Fyreaway]

...now skim off that foam, lol.

That foam turned out to be a treat for the bees. When I skim I just fling the crud out the door. My son just hived his packaged bees and they were really enjoying the maple treat.

[Cedar Eater]

I've made some progress on the kitchen sink to e-Vaporator conversion, but I'll take it to its own thread. Thanks, Fyreaway, for the inspiration. There are many ways my design is not as good as yours. I won't be using it to finish syrup or warm it for bottling, because it will take at least two gallons to cover the element, but if it boils water more cheaply than propane can, it will be worth what I'm spending on it. ;D

[bkeith]

In another hobby, where they boil liquids to separate the vapours from what remains in the pot, they use beer kegs with one or two water heater elements. Run them on 240VAC to heat up, then switch to 120VAC for a constant simmer. The foil backed bubble wrap insulation keeps the heat in the keg quite well.

A beer keg on it's side, cut in half or slightly higher, would make a nice sized sap e-boiler without the major fabrication cost.

Something I'll ponder for next Spring.

[Dennis H.]

bkeith, what other hobby are you talking about?:rolleyes::D

[Fyreaway]

I've made some progress on the kitchen sink to e-Vaporator conversion...

The fun part is you don't really know that anything you do will be less than what I've done. My design has a V-bottom that works pretty well. A flat bottom sink might very well be better. Without playing around with the options we would never know. Using the sink to boil off the bulk of the water and then finish with what you're familiar with sounds like a good plan. I'll be watching for your thread on the new build.

[Fyreaway]

In another hobby, where they boil liquids to separate the vapours...

I learned a lot from those folks, reading posts by the shine of the moon. I 'still' remember how much help they were in my crazy pursuit to make syrup.

What I've found in regulating the current flow is that anything that reduces the heat output will work. Spending the money on the PID controller gives almost perfect control. With that magic little box I can slow the input to any percentage of maximum draw. In the middle of a boil I run it full throttle and can drip sap in to maintain a good boil. If I remember right, the fairy dust that runs the heating elements drops to 1/4 with half the voltage input. I don't understand it but it sure is a good way to slow things down. I like the bubble wrap idea. There's only a few places where that stuff really works and this just might be one of them.

[Cedar Eater]

In another hobby, where they boil liquids to separate the vapours from what remains in the pot, they use beer kegs with one or two water heater elements. Run them on 240VAC to heat up, then switch to 120VAC for a constant simmer. The foil backed bubble wrap insulation keeps the heat in the keg quite well.

A beer keg on it's side, cut in half or slightly higher, would make a nice sized sap e-boiler without the major fabrication cost.

Something I'll ponder for next Spring.

Aren't most beer kegs aluminum?

[saphound]

Aren't most beer kegs aluminum? They come in both aluminum and stainless. You can buy them online, but they ain't cheap. I think a used sink is probably the cheapest SS your going to find. Steam table pans are under 20 bucks, I just wish they came a little bigger.

[67HEAVEN]

The stainless steel sink idea is also intriguing. I can imagine salvaging the sink portion of a kitchen cabinet. That would provide a place to drop the sink into, nice height for working, and you could even stuff insulation up and underneath. Why not run taps on it, while we're at it, to assist in the clean up process. :lol:

If a fitting could be found to convert the large centre drain to something appropriate for draining off, the sky's the limit.

[Cedar Eater]

The stainless steel sink idea is also intriguing. I can imagine salvaging the sink portion of a kitchen cabinet. That would provide a place to drop the sink into, nice height for working, and you could even stuff insulation up and underneath. Why not run taps on it, while we're at it, to assist in the clean up process. :lol:

If a fitting could be found to convert the large centre drain to something appropriate for draining off, the sky's the limit.

I'm working on that fitting in the In-Sink-Evaporator thread. If I find the parts I need, I'll post links to them.

[67HEAVEN]

I hadn't noticed that thread, Cedar Eater. Here's a link for others - http://mapletrader.com/community/showthread.php?25880-In-Sink-Evaporator
See you over there.

Meanwhile, thanks to Fyreaway for generating all this creativity. I'll continue reading this thread as well. http://i49.tinypic.com/30kg3fs.jpg

[loubard]

I'm very impressed with your setup.

This is my first year boiling as a hobbyist in my backyard, and I'm already trying to find a way to move to electricity. I'm planning to build my own electric evaporator and this is the first successful diy project I found.

I like the V shape design of the sides of your evaporator and I was wondering if you also had a slope from back to front to allow for draining?

What thickness of SS would you ultimately recommend?

I was wondering if you could provide more dimensions on your evaporator, or a basic version of a plan?

Have you experimented with a system to continously re-feed cold sap as the water evaporates?

Sorry for all the questions, your project is making my brain spin. Thanks for posting!

[Fyreaway]

I was wondering if you could provide more dimensions on your evaporator...

Welcome to our sappy discussion! I don't have plans for the boiler I made. With rough dimensions it's not too hard to figure stuff out from the pictures. I think the thing is made of 16 gauge stainless. It seems to be plenty sturdy but if the budget is as high as the dream I'll have the next one made a bit thicker. It's about 17" square and 12" deep from the bottom of the V. The V is a 90 degree angle and the vertical bits of the walls are 3" tall. I did use some maths to get the basic dimensions. It will hold five gallons of liquid when filled to the top of the angled section. The 3" riser is nothing magic, just what was left on the sheet without making another cut. The cradle that it sits in has a 1/4" difference in height from end to end so the metal work didn't need to accommodate a drain slope. I feed sap from a 5 gallon bucket perched precariously on a shelf above the evaporator. I find that the precarious perch is helpful because everything else works so well I had to leave something to chance. I have a bulkhead fitting in the side of the bucket and feed through clear tubing with a needle valve to regulate flow. I have thought about flattening the bottom angle a bit to add to capacity but after further review I think I'll keep it the same. It only takes a gallon to cover the heating element and that has turned out to be a useful quantity for a very small run. You've got time to putz around with next year's evaporator. Let the fun begin!

[saphound]

I know a guy that is using an electric turkey fryer to preheat sap. That would be one way to go all electric. He actually has 2 of them and has made syrup with them, but the boil is a little slow so now he uses a propane burner and those to preheat.

[Cedar Eater]

I know a guy that is using an electric turkey fryer to preheat sap. That would be one way to go all electric. He actually has 2 of them and has made syrup with them, but the boil is a little slow so now he uses a propane burner and those to preheat.

I wonder if those small on-demand water heaters that they use for bathroom sinks could be repurposed for preheating sap on-demand.

[Fyreaway]

I wonder if those small on-demand water heaters that they use for bathroom sinks could be repurposed for preheating sap on-demand.

I think that the on-demand heaters need a minimum flow to activate the heat source. I don't know what that minimum flow is but there has to be a safety so a dripping faucet doesn't keep making hot water all day. As with all things, there are ways to bypass controls and make the unit do what you need. Of course, I would never do such a thing!

[lpakiz]

I took my old coffe maker apart. Under the warming platform is a horseshoe shaped (aluminum?) tube that consumes 600 watts. I bet that would preheat sap quite well. It's about the diameter of a pencil. It has its own thermostat, so over heat might not be an issue.

[paulrich]

good info can be found on Heat Source Comparison including electric http://www.kegkits.com/heat_sources.htm

[saphound]

I wonder if those small on-demand water heaters that they use for bathroom sinks could be repurposed for preheating sap on-demand.
Prob would work well, but aside from the flow they require. cleaning would be limited to just flushing water or detergent through the system. They don't come apart..at least not the ones we have. You can replace parts, but can't really get into them to clean where the sap would flow.

[Locust Farms]

Eric,

How many kw's actually used to evap 1 gallon of sap? A 4.5 kw unit @ 3414 btu kw should evap est. 7 gal hr with a 2'x2.5 surf area.

Thanks,

Dwight

[Cedar Eater]

A 4.5 kw unit @ 3414 btu kw should evap est. 7 gal hr with a 2'x2.5 surf area.

His surface area is closer to 2 sqft, but I'm curious how you came up with that estimate for 5 sqft. The reason I ask is because mine will also be close to 2 sqft.

[Cedar Eater]

I think that the on-demand heaters need a minimum flow to activate the heat source. I don't know what that minimum flow is but there has to be a safety so a dripping faucet doesn't keep making hot water all day. As with all things, there are ways to bypass controls and make the unit do what you need. Of course, I would never do such a thing!

Or I could kluge something that works much the same way, just thinking of a SS coil and a heating element that heats a trickler to 180-200 degF. Doesn't seem likely to be very expensive.

[Cedar Eater]

I took my old coffe maker apart. Under the warming platform is a horseshoe shaped (aluminum?) tube that consumes 600 watts. I bet that would preheat sap quite well. It's about the diameter of a pencil. It has its own thermostat, so over heat might not be an issue.

That would be more along the lines of what I was thinking, except it would be SS and immersed in a small SS pipe so that cold sap would enter the pipe from the bottom, get heated and come out on the top at around 200 degrees.

[Fyreaway]

How many kw's actually used to evap 1 gallon of sap?

Dwight,
Here's where I jump off the train. I have never calculated what it actually costs me to make syrup. My goal was to figure out a way to make the same product cheaper than using propane and easier than wood. My first calculations showed that the cost of electric versus propane was about the same per BTU. When I factored in the efficiency of the submersed heater it all went pear shaped and propane was beaten hands down. The surface area of my boiler is just over 2 ft² and I manage to evap 3-4 gph. Near the end when I stop adding sap the rate goes up. Dealing with such a small production rate the differences are pretty easy to measure. I have to pause Netflix and check the boiler more often as it gets closer to syrup.

[Fyreaway]

Here's my take on preheating sap. Unless I'm able to make use of free energy to bring the temp of the raw sap closer to the boiling point I don't see the benefit of preheating. Wrap a tube around the stack or use the steam from a back pan and it all makes perfect sense. I could arrange a preheating vessel and use the steam from my boiler but I'm not sure that covering that much of the pan would be beneficial. My evap rate goes up when I use a fan blowing across the top of the boiling sap. It's the surface area that makes the difference not the temp of the sap entering the pan. I'm going to use a given number of BTUs to evaporate a given quantity of water. Using a second source of energy to provide those BTUs just adds more equipment to the process. If I can't keep a good boil going as I add cold sap I need to increase the BTU available at the boiler. That being said, if time is a factor and you're looking for a quicker turn around then adding equipment and preheating might make more sense.

Now let's work on the solar preheater and really get a bang for our bucks!

[Cedar Eater]

If an electric preheater is more efficient than a propane-fired preheater, then people who don't go electric for the boil can at least benefit from some sort of immersion type 120 VAC preheater, which would be much cheaper to build than an e-Vaporator and wouldn't require routing a 240 VAC circuit. That's where I see the benefit of adding an electric preheater. It makes the gas burners more efficient. My intent is to stay a small scale hobby producer of maple and birch syrup, with 20 - 30 taps max for maple and 10 or less for birch. So I like the flexibility of being able to use other methods when the primary boiler can't keep up with the sap influx. On-demand point-of-use heaters seem like a useful idea if the temp can be set high enough. Coffee makers and room humidifiers heat water to boiling temp, so they seem like natural candidates for a kluge. I'll look into that after I get my In-Sink-Evaporator running.

The solar preheater could be made with a used Dish or Direct TV antenna with small pieces of mirror or aluminum "furnace" tape glued to the curved surface to focus the sunlight on a glass or metal cup. A Sun-follower to move the antenna isn't that hard to make. Someone else is more than welcome to work up a design for that. I do too much of my boiling at night to think about daytime boiling.

[Locust Farms]

His surface area is closer to 2 sqft, but I'm curious how you came up with that estimate for 5 sqft. The reason I ask is because mine will also be close to 2 sqft.

Hi CE, Trying to get handle on the surface area his 4.5 kw heat source will support for a fast boil when adding a surface breeze which evap faster but requires more btu to maintain boil.

I have extensively used a window fan to apply air to the surface of my 2.5x5.5 flat pan evaporator (wood fired) increases evap rate considerable, also has to be fired hotter with added combust air.

Dwight

[Locust Farms]

Eric,

Another question. How fast do you get a boil in your unit. using full power?

I ask because I installed a 4.5 kw unit in the finish end of my flat pan. It instantly boiled so agressively in 3in of sap, had to shut off.

Dwight

[saphound]

Just based on my limited experience..pre-heating sap makes a huge difference unless maybe you could trickle in sap at about the rate your boiling off water. I didn't have a way to do that so I preheated pots (about 1.5 gal) of sap to boiling on my stove and then poured it in my main boiler outside and it never hiccuped. Otherwise, adding cold sap, I would lose my boil for a good 10-15 mins. That's another hour every 4 pots of sap I didn't have to wait. A slow trickle of cold sap might work..but I haven't tried it.

[Cedar Eater]

Hi CE, Trying to get handle on the surface area his 4.5 kw heat source will support for a fast boil when adding a surface breeze which evap faster but requires more btu to maintain boil.

I have extensively used a window fan to apply air to the surface of my 2.5x5.5 flat pan evaporator (wood fired) increases evap rate considerable, also has to be fired hotter with added combust air.

Dwight

I'm thinking a fan over any evaporator might be a good idea. If Fyreaway can get 3-4 gph from his e-Vaporator, maybe I'll be able to get that from mine.

[67HEAVEN]

I'm thinking a fan over any evaporator might be a good idea. If Fyreaway can get 3-4 gph from his e-Vaporator, maybe I'll be able to get that from mine.

I boiled over propane in the Southern Ontario outdoors and a west wind was always howling across my pan. In my case, a fan would be superfluous. :lol:

[Cedar Eater]

I boiled over propane in the Southern Ontario outdoors and a west wind was always howling across my pan. In my case, a fan would be superfluous. :lol:

Sounds like you could have used a wind preheater. :lol:

[Fyreaway]

...a fan would be superfluous.

67HEAVEN wins the 'word of the day' contest. Well played, sir.

[Fyreaway]

I'm thinking a fan over any evaporator might be a good idea.

Here's how I move the air without excessively cooling the pot.

11701

[Fyreaway]

...then people who don't go electric for the boil can at least benefit from some sort of immersion type 120 VAC preheater

CE,
You're exactly right, that would be a perfect place for a scaled down electric unit. A 1500 watt heater in a hotel pan would heat a fair amount of sap to a helpful rise in temp. Also, as you say, there wouldn't be the need for a dedicated high voltage circuit. The key would be the actual evap rate of the primary boiler. The preheater will only work so fast and if you're boiling faster than that there wouldn't be the benefit.

[Fyreaway]

How fast do you get a boil in your unit.

Dwight,
It takes about 40-45 minutes to bring 6 gallons of sap at 40° to a nice boil. The nice thing is that it starts to steam at about 120° so I know I'm already making syrup! Watching the aggressive boil in a shallow pan is both fascinating and terrifying at the same time. The first time I saw it I really wished I didn't have to run so far to unplug it.

[Fyreaway]

...unless maybe you could trickle in sap at about the rate your boiling off water.

That's how I add sap. Gravity fed from a bucket above the evaporator through a needle valve that I can adjust to keep the level in the pan constant.

[saphound]

That's how I add sap. Gravity fed from a bucket above the evaporator through a needle valve that I can adjust to keep the level in the pan constant.

I see...so I guess the next question is if you could trickle it faster if it was near boiling when it goes in the E-vap. I'm thinking yes. Enough to offset the increased energy costs to do so, I don't know. One way to find out tho...;)

[Cedar Eater]

CE,
You're exactly right, that would be a perfect place for a scaled down electric unit. A 1500 watt heater in a hotel pan would heat a fair amount of sap to a helpful rise in temp. Also, as you say, there wouldn't be the need for a dedicated high voltage circuit. The key would be the actual evap rate of the primary boiler. The preheater will only work so fast and if you're boiling faster than that there wouldn't be the benefit.

Yep, but I'm thinking that heating 3-4 gph to 180+ wouldn't be that difficult for what I have in mind. I would put a heating element straight up in an asparagus pot (they're tall and narrow) or even inside 2" stainless steel pipe. Trickle cold sap in through a 3/8" tube that runs inside the pot to the bottom and take the warm sap out at the top and into the boiler. There might even be some boiling in the preheater, especially if the pot was insulated.

[Fyreaway]

...so I guess the next question is if you could trickle it faster if it was near boiling

It would seem that the answer would have to be... yes. If the primary boiler didn't have to raise the temp of the incoming sap it seems like it would be able to evaporate faster. Using the same energy source for both preheating and boiling shouldn't effect the cost of the system but I would guess that it would reduce the time spent boiling.

This leads me to an unexpected consideration for the larger producers. Why not use a residential water heater for preheating? Residential heaters feed cold water in at the bottom of the tank and draw hot water from the top. If we fed raw sap under simple gravity pressure it would force heated sap out the top into the boiler. Cleaning and maintenance would be a bit of a hassle but from my experience the only real burn on the heating elements comes much later as the sugar concentrates.

[Cedar Eater]

Why not use a residential water heater for preheating? Residential heaters feed cold water in at the bottom of the tank and draw hot water from the top. If we fed raw sap under simple gravity pressure it would force heated sap out the top into the boiler. Cleaning and maintenance would be a bit of a hassle but from my experience the only real burn on the heating elements comes much later as the sugar concentrates.

I thought of using a water heater for some of my projects, but I don't know what the tank is made from. If it's stainless steel, then okay. Anything else, I would really want to know what it is and be able to inspect the inside. I used a water heater as a reactor vessel for making biodiesel, but I never had to crack one open.

[Fyreaway]

I thought of using a water heater for some of my projects, but I don't know what the tank is made from.

I don't know what the tanks are made of either. Should be pretty easy to find out. Most of us just assume that when we use water from the tap it's food grade. Sure would be handy it the liners were stainless.

Might want to give a quick rinse between a batch of biodiesel and the syrup. :)

[Locust Farms]

I don't know what the tanks are made of either. Should be pretty easy to find out. Most of us just assume that when we use water from the tap it's food grade. Sure would be handy it the liners were stainless.

Might want to give a quick rinse between a batch of biodiesel and the syrup. :)

The hot water tanks that I have used cut apart were either glass lined (ceramic) or galvanized.
Dwight

[Super Sapper]

If you getting increased evaporation rate with a fan but need more energy to maintain a boil, is the increased evaporation rate because of the additional energy applied or from the wind? A hood will increase the evaporation rate on a rig over a pan without one especially if boiling outside. Another thought is adding the heating element in your main pan while using propane instead of preheating with it. This would increase the efficiency.

[saphound]

The hot water tanks that I have used cut apart were either glass lined (ceramic) or galvanized.
Dwight
Most are glass lined steel, but you can get stainless steel....pricey tho. I wouldn't use a used water heater for syrup..there's some nasty stuff in the bottom of those. A new one dedicated for sap could work.

[WESTVIRGINIAMAPLER]

Electric stoves are easy to find on Craigslist or in trading times free for hauling or $ 50. 2 steam pans or one large stainless pan on that outside in a lean too or small sugarhouse would make a lot of syrup in a season for not much $$$ for electric. I think most pull 50 amps and that includes oven running, so will all burners on high, it would probably pull well below that. I would guess it would evaporate off 5 gph. If you could build a large stainless pan with sides about 12 to 16" high, you could leave it alone and just check it every 1 to 2 hours and add sap to it. If you wanted to maintain a constant flow going into it, 5 gallon bucket or a small barrell or other larger container with a small piece of copper pipe and a valve could keep a constant stream flowing into it.

[Fyreaway]

is the increased evaporation rate because of the additional energy applied or from the wind?

I'm guessing that an increase in evaporation rate is a combination of both. Perhaps clearing the steam faster allows more molecules to escape the liquid phase. I always thought that a steam hood was more for channeling the steam out of the sugar house but in doing so it also clears the interface at the liquid surface. Makes sense then that it would increase the evap rate.

[Fyreaway]

Electric stoves are easy to find on Craigslist...

I'll bet that getting 5 gph from an electric stove would be very doable. Assuming an average of 2000 watts per burner there's a bunch of energy waiting to be converted into syrup. Using deep pans would allow the system to run unattended for some time but I assume that the evap rate is better running the sap less deep. My first few years making syrup were on a gas stove using four half size hotel pans. I had a siphon setup so I added sap to one pan and it worked its' way around the stove to the last pan. The siphon was much more fun to imagine than it was to use. Bubbles from the boil would migrate into the tubing and break the siphon. It was a bit of work but it was really fun to watch.

If you sell it right, you might be able to install an electric stove on the back deck and convince your SO that it's for summer time cooking!

[Cedar Eater]

Electric stoves are easy to find on Craigslist or in trading times free for hauling or $ 50. 2 steam pans or one large stainless pan on that outside in a lean too or small sugarhouse would make a lot of syrup in a season for not much $$$ for electric.

Putting the burner in the liquid is way more efficient than putting the burner beneath the pan that the liquid is in, especially if you insulate the outside of the pan to minimize heat loss. That's the beauty of using a water heater element in the pan. The pan itself never has to get hotter than the liquid, only the element has to do that. One of the problems with propane that the e-Vaporator overcomes is the loss of heat up the sides of the pan. Electric burners outside the pan has the same problem. I have an electric stove/oven available to me that I'm going to convert into a food smoker, if my kitchen sink performs as well as I hope.

[Locust Farms]

Dwight,
It takes about 40-45 minutes to bring 6 gallons of sap at 40° to a nice boil. The nice thing is that it starts to steam at about 120° so I know I'm already making syrup! Watching the aggressive boil in a shallow pan is both fascinating and terrifying at the same time. The first time I saw it I really wished I didn't have to run so far to unplug it.

According to my calculations , nearly 40% of your heat pontential could be lost through pan sides and ends without proper insulation.
Will build a test unit to see how evap rate can be increased. Will post results
Sap to syrup ratio 84-1 this year.
Dwight

[Fyreaway]

...nearly 40% of your heat pontential could be lost...

I had no idea the losses could be that high. Any idea what kind of insulation is going to work best? We don't need the high temp stuff used in a fire box so that should open up a whole bunch of possibilities.

[Locust Farms]

Foil covered fiberglass , foil towards tank,outer wrap with double bubble reflective insulation. Is what comes to mind.
As we Need to address both radiant & physical heat flow.

Dwight

[Cedar Eater]

My cousin who welded on my sink is intrigued by the idea of building and selling these, probably as just pans, so the buyer can choose his own heating element, valve, support frame, etc. I've already suggested a thermowell near the draw off and a grounding lug near the port for the heating element. Any other ideas?

[TrapperX]

This was such a great read and didn't notice it stopped on page 10 :cry:

I was wondering Fyreaway did you make any improvements for this year?

[Fyreaway]

I was wondering Fyreaway did you make any improvements for this year?

The only improvement so far is making a fitted cradle for the vessel. The cradle is lined with foil faced bubble wrap insulation. If I see an improvement in evap rate I may go for a more insulated box. As always... it's a work in progress.

[Jeff01]

I am seriously looking into building this evaporator Fyreaway. I have drawn up some plans and a friend is going to help weld it. Do you have any upgrades since your last post? Did you see an improvement in the evap rate after adding the insulation?

Thanks in advance.
Jeff

[Fyreaway]

...Do you have any upgrades since your last post? Did you see an improvement in the evap rate after adding the insulation? Jeff

Yep, the insulation helps a lot. My most spectacular upgrade was due to a spectacular failure. It seems that it's pretty important to have the electrical connections well isolated before sliding in the piece of foil lined bubble wrap. Luckily I only contacted one leg of the 220v connection so it was not life changing but still a harsh wake-up call. This is a pretty simple machine and you should be able to get away with a minimal investment to see if it works for you. The PID controller I use is mostly to give me something to fiddle with while I'm boiling. You could very well just plug the thing in and unplug when you're done.

[Jeff01]

Definitely need to respect 220 volts. I found an element enclosure on one of the brewing websites. It covers the terminals and adds a ground connection as well. Thanks for the tip on the PID controller. I think I’ll just wire it up straight and add the PID next year. Running out of time here, I drilled some test holes today and have sap flowing. I hope to have the evaporator set up and ready to go by the end of the week.

[Lucky Dog]

This is a great thread, thanks!

For those of us that don't understand electrical things, could you explain what the PID controller is and what it does?

[Cedar Eater]

This is a great thread, thanks!

For those of us that don't understand electrical things, could you explain what the PID controller is and what it does?

PID controllers are pretty versatile. Instead of just on or off like a switch, they read an input temperature (or pressure, flow, whatever) and adjust the output power. So if you have an oven on a PID controller it would apply full power until the temperature gets up near the setpoint and then it would back the output power off to a trickle to prevent or minimize the temperature overshoot. Then if you open the door on the oven, it would see the temperature dropping and try to pull it back up. In the case of boiling sap, you would set the setpoint at the boiling point of water, but if the boil was too vigorous (more power than the amount of sap needs to have ), you could back it down some.

[Lucky Dog]

Thank you Cedar Eater.