Saturday, September 11, 2010

Performance questions and answers

Ahmad from Kuwait wrote:

Dear George,
I really consider myself lucky to find your book on the internet while looking for information about more secrets of the design of solar heating systems.
I already constructed a system of my own design few months ago, which is still in operation for the heating of my indoor swimming pool (18000 Galons), but I was hoping to find information about sun tracking systems, when I came across your wonderful book, which I purchased a soft copy of.
I have questions in order to clarify some issues, as follows:
1- What is the atmospheric temperature that you have in the project site?
2- What is the initial temperature of your swimming pool water?
3- How long it took to heat up the water in the pool to the temperature of 28 degrees celsius?

Hello Ahmad,

Thank you for your kind comments and for purchasing my book (info about book)

About your questions, it sounds like you are trying to understand performance. I think my conditions here near Toronto, Canada are not like yours in Kuwait! My pool is outside, it is 50000 gal and the weather here must be the worst to attempt solar heating.

Our average summer temperature is about 28C although we have highs of 35C. The temperature can drop significantly at night, to 15C so this tends to cool the pool. Only twice this summer I had a pool temperature at the end of the day of 28C. Many days in the summer here are overcast with cloud cover and near useless for solar heating although the air temperature might be warm. We get rain periodically here in the summer which tends to cool things down. You get the idea.

I suggest that the best way to predict what might be possible in your situation is the actual heating measurements I made.  These are detailed in the section Performance Measurement on page 88. (this blog posting was the basis for that chapter)

In particular, the heating value of 3705 BTU/hr (1086 kWhr) for one collector might be the most valuable for predicting what you might expect there since it normalizes all the differences between our pools and climates and is the actual heat output of one collector at an instant in time when the sun is shining in a clear sky.

Thanks for your interest,
George Plhak 

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