i need to pick your brains. wheres Simon F lol

[scottyblen]

when it comes down to heat and calculating the amount of heat required 60 mins X 60 seconds=3,600 gives me the number of seconds in an hour right?

the book i have been reading from states "1000 joules over 1 second X 3,600 (number of seconds in one minute)

i am lost.

 

[PlumbBobBob]

that will be 3.6kj (kilojoules)

 

[scottyblen]

that will be 3.6kj (kilojoules)

not following.

 

[tamz]

The amount of heat required for what? Give us a clue and you will get an answer.

 

[scottyblen]

i just didn't understand that part of the text in the book.

the specfic heat capacity 4.186.

lets say there is 150 lts of water the current temp of that water is 4 degres C. I want to get it 80 degres C.

so thats 150 ltrs X 4.186 X (80 - 4) = 47,720.4

47,720.4/ 3600= 13.26 KWH

 

[Billy Bob Bob]

buy a mears

 

[tamz]

Right i better find the calculator then :smile:
Q = mc⌂T
m = the mass (in this case 150 litres)
c =the specific heat capacity (water is 4.186 joules/gram (or watt/seconds))
⌂T = the temperature rise (in this case 76°)

Your mass should really be converted to grams (1 litre is a kg so needs multiplied by 1000) but don't do it here unless you want the answer in watts as it is easier and would need converting back.

so
150 x 4.186 x 76 = 47720.4
this answer is how many kw you would need to raise the temperature of 150 litres of water by 76°C in 1 second which is useless to you as you probably want to know how long it would take a 3kw immersion to do that
so
divide 47720.4 by 3(for a 3kw immersion) = 15906.8 then divide that by 60 (seconds in a minute) = 263.11 minutes to raise the temperature

 

[Billy Bob Bob]

Right i better find the calculator then :smile:
Q = mc⌂T
m = the mass (in this case 150 litres)
c =the specific heat capacity (water is 4.186 joules/gram (or watt/seconds))
⌂T = the temperature rise (in this case 76°)

Your mass should really be converted to grams (1 litre is a kg so needs multiplied by 1000) but don't do it here unless you want the answer in watts as it is easier and would need converting back.

so
150 x 4.186 x 76 = 47720.4
this answer is how many kw you would need to raise the temperature of 150 litres of water by 76°C in 1 second which is useless to you as you probably want to know how long it would take a 3kw immersion to do that
so
divide 47720.4 by 3(for a 3kw immersion) = 15906.8 then divide that by 60 (seconds in a minute) = 263.11 minutes to raise the temperature

you have lost your mears,or are sober LOL

 

[tamz]

you have lost your mears,or are sober LOL

I'm sober :lol:

 

[Billy Bob Bob]

I'm sober :lol:

lol,jobs a good un

 

[PlumbBobBob]

I'm sober :lol:

must be working tomorrow then:26:

 

[tamz]

I'm one of the lucky ones :wink: