Monday, January 9, 2012

Thermodynamic Math

 http://groworganic.com/organic-gardening/articles/heating-greenhouses
 I suggest using the site above.  

This page is a work in progress which I will continue to update
I'm seeking help from others for this and any other advise.
I checked my visitor stats and it appears this is a popular page.  I feel bad that I have yet verify these calculation, and want to say right up front -  These spread sheets need to be checked by someone familiar with this topic.   

I'm going to leave these two spread sheets alone for awhile, but if you would like to take a look at my progress, you may download them at these links.  
ThermDynamicDensity Spread Sheet - Formulas for Specific Density, Heat Density, Volumetric Heat Density, Conductance and conversions between the various system units.

 BTU Calculator  - Examines Costs and Design of Thermal Collection, Storage, and Heat Exchange

I'm anxious to get started, and I feel that I have learned enough to proceed with the aquaponic system before working out all the details of temperature control, and a mathematical model of the entire system. It really comes down to conservation, and in my case 80% of the loss will be through the glazing.  It seems the more economical approach will be to address this one issue.

I can't guarantee that the formulas are correct, but you may find them useful if you too are trying to work through these calculations.  My goal is to create a spread sheet that will offer a systematic approach, and all the calculations required in the design of a year round thermally balanced (72F +/- 10F) aquaponic green house system using solar to accomplish a minimal utility demand.

Eventually I would like to incorporate a graph to show the rate of change as the differential temperatures of the thermal storage and the aquaponic system change.

Here are some links I found useful, and some considerations I have pondered.


This is Good Information and A Great Calculator!
Link to these Calculator


I feel that the ThermDynamicDensity Spread Sheet has been verified. it's unfortunate that thermodynamic formulas are presented in so many different units.  I have done my best to verify the formulas from several sources, but the conversions become quite complicated.

Some conversions come from
http://www.gordonengland.co.uk/conversion/

Below I have attempted to set these calculators equal to the same measurement of 1 BTU = 1F and 1 British Pound.
In the Volumetric Calculator I used 1 BTU / 10 Imperial Gallons. 
I derived that from http://en.wikipedia.org/wiki/British_thermal_unit
"It is approximately the amount of energy needed to heat 1 pound (0.454 kg) of water, which is exactly one tenth of a UK gallon"

CLICK HERE for a video about calculating the energy captured from the Sun.

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