Beer Forum

Leave it to McMaster Carr. Years of engineering school and higher math to have most of my engineering career bottle neck down to algebraic equations. I am wanting to move to a 240V immersion heater in the HLT vs. Gas fired. I will leave the BK gas fired however. Found this equation for immersion style heaters.

V (gallons) * Delta T (F)
____________________ * 1000 = Wattage Rating of immersion heater
372 * Heat up time (Hrs)

Example - 3 Gallons of water for mash in, 60F to 168F, in 15 miniutes (0.25 hours) = 3484W or 3500W approx. Equation assumes water only. You can see their website for liquids of different densities as well. FYI

take care all!

This may be of help also.
viewtopic.php?f=2&t=10822&p=103792&hilit=element#p103792

codewritinfool wrote:This may be of help also.
viewtopic.php?f=2&t=10822&p=103792&hilit=element#p103792

Thanks Code!

All you have to remember is that 1 KW is equivalent to 3414 BTU/hr and that water weighs about 8.34 pounds per gallon. Thus in the example where it is desired to raise 3 gallons through a 108 °F rise the heat requirement is 3 x 8.34 x 108 = 2702.2 BTU. If this is to be accomplished in 1/4 hour then the heat input rate must be 2705.4/0.25 = 10808.6 BTU/Hr which is equivalent to 10808.6/3414 = 3.166 kw. That's all there is to it assuming 100% efficiency. The McMaster Carr formula apparently assumes 91% efficiency.

ajdelange wrote:All you have to remember is that 1 KW is equivalent to 3414 BTU/hr and that water weighs about 8.34 pounds per gallon. Thus in the example where it is desired to raise 3 gallons through a 108 °F rise the heat requirement is 3 x 8.34 x 108 = 2702.2 BTU. If this is to be accomplished in 1/4 hour then the heat input rate must be 2705.4/0.25 = 10808.6 BTU/Hr which is equivalent to 10808.6/3414 = 3.166 kw. That's all there is to it assuming 100% efficiency. The McMaster Carr formula apparently assumes 91% efficiency.

Excellent info, ajdelange. Of course, you just know I had to go plug your numbers into my equations and it came out 15.01 minutes, so I was pleased. I also admit that the geeky engineer in me had me considering, if only for a split second, where the rounding errors were.