How does Power Influence Water Heating

http://www.simetric.co.uk/si_steam.htm gives some idea.

actually thats not the 9Ampere current,it gives 2500watt power...

For everyday purposes, the thermal capacity of water can be taken as 4.18kJ/kg.degC.

DO THIS:

1) AMPS X VOLTS = WATTS

2) WATTS/1000 = KW (KILOWATTS)

3)1KW = 3413 BTUs

4) 1 BTU RAISES 1 LB WATER 1 dF

5) 8.3 LBS WATER = 1 GAL.

EXAMPLE: 9 AMPS X 230 VOLTS = 2070 WATTS / 1000 = 2.07 KW

2.07 KW X 3413 = 7065 BTU

RAISE 1 GAL WATER 10 dF = 8,3 X 10 = 83 BTUs

7065 BTU / 83 BTU/GAL = 85 GAL RAISED 10 dF

Now plug in your own numbers...

If you read 2500 watts, then with 9 amp load, you have 277 volts.......Sounds like single phase of a 480 volt circuit.

So, with 2500 W or 2.5 KW, then 2.5 x 3413 = 8533 BTU, then 8533 / 83 = 103 gal raised 10 dF.

Hello Old F**T - just to be clear, this is in one hour. Watt is power, BTU is energy.

Cheers....Codey

CODEY...........You are correct, thanks.

Unfortunately, old F**T's like me take too many things for granted. After nearly 6 decades of engineering practice in HVAC&R where by common consent, we interchange terms, like BTU & WATTS, etc, which are not correct without defining them, but is generally understood. I do have trouble in converting some of the terms used today which I'm not familiar with.

Todays question apparently involves a 2500 watt water heating element, and the author is trying to determine how much hot water it will produce. As is typical, we were not given enough information to really make a definitative answer. ETC...ETC...

Cheers to you, too

g scott

Why do you need to go BTU, gal and dF.

Keep it in Joules, liter and dK

to raise a liter of water with one degree (Kelvin) you need 4186.8 Joules

2400 W is equal to 2400 joules / sec.

Now you can easily calculate which time it takes to heat up.

Take into account that you need to heat up the boiler and the insulation to. The losses will go up with the temperature, slowing down the heat up process.

The resistance of the heater will also go up with the rise in temperature, reducing the power.

Thermal heat-up is the easiest type of calculations to do, until you need to be accurate and you boss is not lucky as the heat-up took longer than predicted, reducing the output of an investment.