Watts to heat water ?

[PaulM2]

I'm heating a water tank of 120 gal. from 80F to 120F in about 3 hours. I use a homemade outside wood furnace kinda thing to heat water through a pipe into my house in this large storage tank to preheat water before my furnace. I was hoping someone here could give me their calculations as to how much electricity it would take in watts to heat this amount of water in this time.

 Thanks to you who are good in math!

[windstuffnow]

  I came up with 2500 w/hr just doing a quick mental calc.  

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[PaulM2]

So that would be about 7500 watt hours or 7.5kwh ? to heat that water? Wow.

[pwr]

It takes one Btu uf energy to raise one pound of water, one degree F.  Water weights about 8.3 lbs per gallon, so 120 gallons weighs about 1000 lbs.  Temperare rise is 40F, so it takes 40,000 Btu to heat 120 gallons from 80 to 120F.

Converting Btu to kWh yields 11.7 kWh, so call it 12 kWh.

[XeonPony]

Q = M*C*(Dt)

Q = 455(Kg)*4.19*22Cdt

Q = 41942.0/(3200*3)

Kw/h = 4.4

So you need to pump in 4,400W for 3 houres!