Integration problem with a power/time curve

Hi everyone. First time poster, so be kind!

Hopefully, this is quite a simple problem for somebody to help me out with.

http://imageshack.us/photo/my-images/7/picture1paf.png/

The above image shows a power/time curve which represents the power output of a solar PV module. Obviously the area under the curve is daily output energy of the module. I want to find this figure but am a little stumped by the decimalised time. 0.3 & 0.7 represent roughly 7am & 5pm respectively of a typical February day in the UK.

Currently trapz of the curve (obviously) gives me the wrong answer. Ideally, I want the energy yield in Wh.

Any ideas?????

Answer 1

[Matt Fig]

trapz(x,y) should give you W-Day. So take that answer and multiply by 24.

[David]

Thanks for replying Matt.

However, I'm not sure that will give the right answer. Theoretically, the curve could be shifted way to the left by 0.2. The integral would give me a reduced value, but in reality the energy yield would be the same.

[David]

Haha...ignore that. I'm being SUPER stupid.

[Thsmia Kausser]

Can you explain why we need to multiply by 24 ?