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combi99
24-05-2014, 01:46 PM
If a system has a COP of 4 and an output of 9kw when in heating, would the cooling capacity be

2.25kw or 6.75kw

Thanks Chris

r.bartlett
24-05-2014, 03:08 PM
what do you understand by COP?

combi99
24-05-2014, 05:13 PM
RE/WD
It's an exam question.

r.bartlett
24-05-2014, 06:02 PM
which I guess means you don't know.

http://en.wikipedia.org/wiki/Coefficient_of_performance

the equation is right there which will get the answer you need.

combi99
24-05-2014, 08:18 PM
I'm still confused by this...

r.bartlett
24-05-2014, 08:28 PM
Sorry I don't like just telling people answers, if it seems they are more interested in passing the exam than learning.

The answer is there for you to work out, I will help you get to the answer if you are interested in learning rather than just wanting to skive through life. if you can't be arsed then you are someone who I have absolutely no iinterest in helping..

My opinion but if someone else wants the glory then so be it. Good luck drifting through life..

I'm out

combi99
25-05-2014, 11:23 AM
I agree with what you saying in principle but I find when I'm working out maths questions I learn the problem a lot better if I work backwards and can assign numbers rather than letters to an equation.


My understanding is that in heating for ever 1kw of energy your putting in with a cop of 4 you get 4kw back.
so a 9kw system must be using 2.25kw of energy to run it.

In which case a 9kw system in cooling would require me to minus the energy being used 2.25kw from the 9kw which would be 6.75kw.?

combi99
26-05-2014, 08:51 PM
Anyone.????

The Viking
26-05-2014, 10:44 PM
In which case a 9kw system in cooling would require me to minus the energy being used 2.25kw from the 9kw which would be 6.75kw.?

Which brought you to the right answer, well done.;)

The actual, real life, figure will vary slightly depending on the equipment as there are some variables and deferent way of measuring.
However, as most of us engineers see it: cooling capacity + input power = heating capacity.

Good luck with your studies.

:cool:

combi99
28-05-2014, 05:30 PM
Thanks for confirming that Viking :-)