Re: [EnergyPlus_Support] CCP climatic cooling potential

[Joe Huang <YJHuang@xxxxxxxxxxxxxxxxxxxxxxxx>]

Just wanted to add that I think the CCP metric seems problematic to me.  It looks like it's simply summing up the number of "degree days" over the entire year, without differentiating between summer nights, when the "free cooling" would be beneficial, and winter nights, when it would just add to the heating load and not desirable at all.  If you look at the plots, notice that the largest CCPs are in the coldest locations (Moscow, etc.) and smallest in the hotter locations (Athens, etc.).  That seems counter-intuitive to me.  I'd suggest that you take a good look
at the statistics and perhaps improve it (?) by only counting the "degree days"  when the average outdoor temperature is above a certain threshhold, like 18.3 or 15 C.

Joe


On 4/9/2013 8:21 PM, Joe Huang wrote:

From scanning the paper and looking at the plots on the last page, it looks a cumulative frequency plot of all the nights.  Therefore, just calculate the
difference in degrees between the assumed indoor temperature sine curve and the outdoor air temperature for the hours between 7 pm and 7 am and add
them up for each day.  That should give you 365 numbers of CCP for each night.  Then, sort the numbers from the highest to the lowest, and you should get a line plot as shown.

Joe

Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 108D
Moraga CA 94556
yjhuang@xxxxxxxxxxxxxxxxxxxxxxxx
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On 4/9/2013 6:08 PM, regen555 wrote:

 

Hello,

This may be off topic, so you can contact me privately.
I am trying to build up a plot as shown on the last page of:
http://tinyurl.com/c2k8yhr

Climatic potential for passive cooling of buildings by night-time ventilation in Europe
N. Artmann, H. Manz and P. Heiselberg
Applied Energy, 2007, vol. 84, issue 2, pages 187-201

I have an EPW file for my location. However my question is how should one go about doing the summation of all the CCP (= degree-hours) per night please? I can open up the EPW in Excel, then superimposed the sine wave oscillation for the room temperature.. and then?

Any help is sincerely appreciated..!

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