boil-off

[Minbari]

Boil off rate is primarily dependent on wattage or BTU of the heat source.

It takes 2731 watt-hours to evaporate a gallon of water at 212F. So if you have a 1600 watt heat source, the maximum possible boil off rate is 1.71 gallons per hour. However, that assumes a 100% heat transfer efficiency. In my experience with a 1600 watt vessel, I get a boil off of around 1.5 gallons per hour. This would be a thermal efficiency of about 88% which seems about right.

So 2 gallons with 4500 watts isn't out of range

 

[Zambi]

Man, metric is king
1 calorie is the amount of energy needed to raise the temperatureof 1 litre of water by 1 oC
OK, I admit, calorie does not belong to the SI units.... (It's joules these days)

And still, you need to recalculate to watts

 

[Ozarks Mountain Brewery]

don't forget the width of the pot, the more surface the more it boils off

 

[Bubba Wade]

So 2 gallons with 4500 watts isn't out of range

Not at all. Remember that the 1.71 gallons per hour with a 1600 watt heat source is the theoretical maximum. Due to thermal inefficiency and other factors, actual will always be lower.

 

[Bubba Wade]

Man, metric is king
1 calorie is the amount of energy needed to raise the temperatureof 1 litre of water by 1 oC
OK, I admit, calorie does not belong to the SI units.... (It's joules these days)

And still, you need to recalculate to watts

When I looked up the heat of vaporization, it was 2256 kJ/kg. I had to do a fair amount of unit conversions to come up with kW-hr/gallon.

 

[west1m]

Boy is my math off!
With those numbers I would have thought if if I only had 1600 watts it would I would only boil .58 gal out of that 2731/ hour.
(Sorry not an engineer)

 

[Bubba Wade]

Boy is my math off!
With those numbers I would have thought if if I only had 1600 watts it would I would only boil .58 gal out of that 2731/ hour.
(Sorry not an engineer)

And that’s why engineers always have someone check their work. Good catch on the 1/x error.

 

[Bubba Wade]

And that’s why engineers always have someone check their work. Good catch on the 1/x error.

And the worst part was that I checked all the numbers to make sure the conversions to get the 2731 watt-hrs/gal was correct. Then I put the wrong number as the divisor.

 

[west1m]

I wasn't sure at first, then I remembered my Anvil. When I bought it it was set up for 110V 1600 watt. Only boiled about 1/2 gal in an hour . I flipped the switch and run it on 220v now 2800 watts. Boils right at 1 gallon set at 97 % power. So i am pretty sure your 2731 wh is spot on.

Ps after reading my post it sounds bad. Didnt mean to sound like an a whole.