simulate cool pond with system for passive cooling

ApacheCalc – Heat loss/gain calculations using CIBSE procedures to determine design heating/cooling loads.
ApacheLoads – Design heating/cooling loads calculations using ASHRAE Heat Balance Method.
macpavee
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simulate cool pond with system for passive cooling

Postby macpavee » Fri Jul 12, 2013 1:40 am

i am looking to use a nearby pond to capture a little coolth for the simulation and try also with a roof pond.

the evaporative cooling element needs to be guessed at.

although the exact(ish) evaporative cooling figure can be calculated via the Penman Equation we can probably get away with an approximation for the sim and check the equation against the monthly totals.
as i certainly dont have the skills to program in that formula and all it's functions into IES....if it would fit and work that is.

if interested see: http://www.bsyse.wsu.edu/joan/teaching/bsyse556/W7/L7Joan.pdf

in the meantime and for a landscaped element at least,
assuming the pond maintains a temperature approximately in line with the WBT which is also around 7 - 10 degrees C lower than the DBT and also laggs behind the DBT by 12 hours...

http://books.google.co.uk/books?id=ZkUfRu7y3sMC&pg=PA7&lpg=PA7&dq=the+use+of+landscape+elements+in+passive+cooling+strategies+in+building&source=bl&ots=ox1BLuoDhx&sig=2vQh6yckJ592krvghvfxGCxYT_U&hl=en&sa=X&ei=xVvfUfO_KOuY0QW8l4G4CQ&ved=0CDMQ6AEwAA ref. page 174.

or

http://www.plea2009.arc.ulaval.ca/Papers/2.STRATEGIES/2.2%20Heating%20and%20Cooling/ORAL/2-2-08-PLEA2009Quebec.pdf page 6.


....the question is how do i type a formula control into IES to achieve the desired effect?

any boffins :ugeek: out there?

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Marc Jensen
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Re: simulate cool pond with system for passive cooling

Postby Marc Jensen » Mon Jul 22, 2013 1:00 am

You could set up the pond to be a room with your desired properties and use the equation generator in IES, abeit very very simple you could set the temperature as your pond room to lag the outdoor area quite easily however the impact of the evapotranspiration is another story. I know it ahs been mentioned in other threads and they found it to be hard/inaccurate. You could manually enter in your settings.

Here is an idea, how about making your own custom weather file to have a greater moisture content/ more wind or lower temperatures on say the north etc. I have never done this so this would probably not even be possible but is another way to look at it.

Good luck Mac
Regards,

Marc Jensen,

macpavee
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Re: simulate cool pond with system for passive cooling

Postby macpavee » Wed Jul 24, 2013 1:32 am

thanks for the reply marc

my problem is that i am not very good with the absolute profiles.

i have tried simply making the heater/cooling set point at a cooler level through the summer (8*C) but this just froze the room. -i dont know why. this is what i wrote:
ta=(8<to)

i am fine with modulating profiles and setting up the annual changes, i dont know (understand) how to write the absolute formulas.

any clues?

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Complex Potential
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Re: simulate cool pond with system for passive cooling

Postby Complex Potential » Wed Aug 14, 2013 8:27 am

Hi Mac

A bit late with this one but I dont normally frequent this part of the forum.

The absolute profile you want would more likely be something like this:

to-8

It is that simple. There's no need for the "=" since the resultant variable is already defined based on what you apply it to.

CP

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Re: simulate cool pond with system for passive cooling

Postby macpavee » Fri Oct 04, 2013 7:51 pm

Thanks CP...again.

yes that is simple ....and obvious really when i look now. :oops:
i suppose my poor brain was getting rather weary at that point.

but i am really looking forward to the new testing of my design with this addition.


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