Thursday, August 6, 2009

Temperature Perfrormance

I finally have some actual performance data on the first solar cell.

This is from a test run that I did with 100 litres of water in a black plastic container over about 6 1/2 hours:


Time
Water TempOutlet TempBox Temp
Ambient
11:00:0020
21.737
20
12:10:0027
28.4
30
20
13:36:0033
34.4
43.5
22
15:00:0036
37.2
47
23
17:17:0037.8
37.8
30.5
23
18:20:0035.5
35.3
29
22

This shows the unit can pick up a fair amount of heat - 17.8 degrees C in around 6 hours. Since 1 Litre of water is equal to 1 Kg of water and it takes 1 Kcal to heat 1 Kg of water 1 degree, this means the system put 1780 Kcal of heat into the water which equals 7,447,520 joules or 2.0687 kilowatt hours.

This shows the result graphically:


What is interesting here is that as soon as the sun goes off of the tubes and box cools down, the system actually starts to radiate heat and cool the water!

As to whether this would help with the pool situation, the numbers aren't very encouraging! If it can heat 100 litres of water by 17.8°, this means it would heat 1,000 litres by 1.78° and 10,000 litres by only 0.178°! Unfortunately, the pool probably holds 40,000 litres, so even two solar units might only provide 0.112°! Well, I will continue with unit #2 and then see where it goes. I can also work on the positioning and angles for the units as well. Currently they are just pointed roughly South, but it may be worth checking different positions.

By the way, when I checked how much the 100 litres of water in the container was heated without the solar heater it was only one or two degrees, so the unit certainly does something!

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