Using surface area to caculate evaporation rate

[wiam]

Well lets look at how rigs are mad now.
There is an infinite adjustment to the float box...this is so you can get the depth adjust to your way of loading the firebox and to how warm your sap is coming in to the unit.
On our unit why have three points of adjustment market. 1-2-3. One is where we set the float when we shut down for the night. This is the lowest setting.
This way there is as little in the pan soyou can get up and running as fast as possible. This leaves about 3/8" over the flue tops.
At 2 you have about 1/2" and this works good if you don't open the hood and the rolling boil will keep everything covered and you are all good. But when I walk in to check the pan the bubbles recede and I see pan that is not covered with sap and FREAK OUT. So I set it to three.

At three the boiling rate is reduced and I sit there scratching my head and wonder why boiling rate slows.

There is a simple mathematical equation that my be found in plumbers books but you an find on the web. It is for furnaces and is to calculate there efficiency. It takes the BTUs the furnace makes and the amount of water in the furnace and the capacity of the systems pump and gives how many square feet of house can be heated.

This can be used for your quire. You can calculate the capacity of your pan in cubic feet and then figure the BTUs you can supply and you can figure the boiling capacity from there.

One calorie is the energy to raise one gram of water 1 degree centigrade. How many BTUs to raise a gallon 1 degree centigrade. When you are at 99 degrees 1 degree will make her boil.

what is the temp of the incoming sap? This must be brought from say 5 degrees to 100 degrees. if you are bringing in 40 gallons of 5 degree sap how many BTUs to bring this sap to 100?

I am sure you can look at CDL or Bascoms catalogues where G/H rates are listed and get a calculation or at least a chart on productivity an compare the sizes.

But the manufactures numbers are bogus. Because we all run them differently. Some run for fuel efficiency. Others run as fast as possible. When I had my 2x6 Mason I got way over rated evaporation. But I was running 1500 degree stack.

[Maple Man 85]

BreezyHill thanks for the information, I know a few plumbers that may be able to help with this calculation. As for manufacturers numbers I would agreed there is deviation because I do not believe there is industry standardized testing in regards to creating consistent and accurate numbers. If the industry continues to grow I would expect a study such as this would provide producers with valuable information from a business perspective to maximize profits in the sugarhouse. The ultimate goal of the research is to share it with the maple community so producers can keep more of our profits (lord knows we work hard enough for it).

[mudr]

It would be interesting to see an industry standard. The epa has a standard to test btus from wood stoves, I could envision something similar. For instance, to compare pans, boil on a fuel oil rig set to a certain degree stack, 1.5 inches of sap above flues. Boil for 2 hrs, calculate total evaporation rate across the 2 hours, and peak evaporation in the middle. It would be interesting to see.

[wiam]

It would have to be amount of oil burned per hour. Not stack temp. A more efficient pan would run a lower stack temp with the same btu's going in.

[BreezyHill]

I think that if you look a cdl catalogue you will find some data on square foor evap rates that they have worked hard to produce.

I am not vouching for the accuracy on these numbers or what variables were addressed as in sap temp into rig, or any others.

Yes we do work hard and as wiam states btus of oil into the unit would be more advantageous than stack temp...as we want everything out of the fuel we burn to heat the sap and as little as possible out the stack.

It would be nice to keep more profits agreed!

[Maple Man 85]

I think that if you look a cdl catalogue you will find some data on square foor evap rates that they have worked hard to produce.

I am not vouching for the accuracy on these numbers or what variables were addressed as in sap temp into rig, or any others.

Yes we do work hard and as wiam states btus of oil into the unit would be more advantageous than stack temp...as we want everything out of the fuel we burn to heat the sap and as little as possible out the stack.

It would be nice to keep more profits agreed!

I reached out to CDL to participate in the experiment but I have not heard back from them. I'll have to checkout the catalogue and see what I can find.

[WESTVIRGINIAMAPLER]

On a standard wood fired evaporator, we figure about 3gph for every square foot of pan. As the efficiency increases, these numbers go up to as high as 5gph on the very high efficiency arches.

I should point out the 3 gph is for a standard evaporator with standard size flue pan and 7" flues.

[Maple Man 85]

On a standard wood fired evaporator, we figure about 3gph for every square foot of pan. As the efficiency increases, these numbers go up to as high as 5gph on the very high efficiency arches.

I should point out the 3 gph is for a standard evaporator with standard size flue pan and 7" flues.

Thanks for the data Brandon, would you happen to know how these numbers were established or if there were studies published that support these numbers?