[darren clarke]

any one know the calculaton for how long water will take to heat up

i have a 400 ltr tank and want to know how long it will take

[Matthew Bateman]

I was interested in this when I bought my 3KW IBC heater last year, basically it boils (excuse the pun) down to the fact that the specific heat is the amount of heat per unit mass required to raise the temperature by one degree Celsius. The relationship between heat and temperature change is usually expressed in the form shown below where c is the specific heat. The relationship does not apply if a phase change is encountered, because the heat added or removed during a phase change does not change the temperature.





The specific heat of water is 1 calorie/gram °C = 4.186 joule/gram °C which is higher than any other common substance. As a result, water plays a very important role in temperature regulation. The specific heat per gram for water is much higher than that for a metal, as described in the water-metal example. For most purposes, it is more meaningful to compare the molar specific heats of substances.

The molar specific heats of most solids at room temperature and above are nearly constant, in agreement with the Law of Dulong and Petit. At lower temperatures the specific heats drop as quantum processes become significant. The low temperature behavior is described by the Einstein-Debye model of specific heat.

[DaveG]

Can you explain the theory of relativity now please Matt?

Thanks in advance 

[luther1]

What Matt's trying to say is that if you park your van behind a Boeing 747 engine with the back doors open,then it will be boiling in a couple of seconds. If you use a hair dryer on medium heat while aiming it at your tank,then several months.

[darren clarke]

cheers matt,   i didnt understand any of it   

i am getting a 3kw 27inc immersion and want to know how long it will take to heat 400 litres

[Dennis Taylor]

After about 2 hrs it will be around 32 degrees C, after 3 hrs about 40 - 42 degrees C.
Thats what mine does anyway and i have the 27" element too.

Dennis

[Matthew Bateman]

cheers matt,   i didnt understand any of it   

i am getting a 3kw 27inc immersion and want to know how long it will take to heat 400 litres

I believe according to the calculation below that it will take 4.6 hours to raise 400 litres of water by 30 °C.

The figure you are concerned with is the one at the top left 13 900. That is the number of hours, 13.9 needed to heat 400 litres by 30 °C with a 1KW heater. You have a 3KW heater so divide 13.9 by 3 and you get 4.6 hours.

[darren clarke]

cheers matt

[Matthew Bateman]

Your welcome. 

[bobplum]

dont forget to take into consideration atmospheric pressure(sea level>mountain top)
and it will expand by 4% at 100 c at sea level
bob

[Frankybadboy]

and the next question for master bateman.................................is........................... : :

[Matthew Bateman]

Steady on............. 

[WinTech]

And the cost to do all this is??

[Matthew Bateman]

Somewhere along the lines of £1.75 Id imagine, depending on the suppliers tariff.

[Smudger]

stone me, still dont understand that !

do us a flavour     3 kw in 900 ltrs from 2 degs to 50 degs

cheers
Batman

Darran

[Perfect Windows]

Simplifying, so you don't need to go to a website:

1. Get a calculator.
2. Take the volume of water you want to heat (in litres)
3. Multiply that by the temperature difference you're trying to make in deg C
4. multiply that by 1.16
5. Divide it by the wattage of your heater in watts. (3kW = 3,000, etc).

That's how many hours it will take.

So, 900L, 48 deg, 3,000W.

Plug them in and you get 16.7 hours.

However, this assumes perfect insulation, so it'll take longer.  How much is impossible to say, but the better insulated the tank, the closer you'll be,

Vin