Actual results:
The car radiators ended up giving 13.000 Watts of heat to the swimming pool and today the pool temperature was 32 C / 90 F. (The last ten days the air has been 15 C / 59 F during nights and 25 C / 77 F during the day and sunny)
When I use 1 Joule of energy I get 30 Joules back...
If Stefan-Boltzmann Law can be neglected in my loft because conduction or convection have say five times the effect, then I have an additional five times the effect directly from conduction/convection.
That makes the challenge of heating the swimming pool by car radiators much easier.
I...
Stefan-Boltzmann Law is great.
You have a surface area of 2 m2 and outer space has a temperature of -270° C (http://www.universetoday.com/77070/how-cold-is-space/)
In outer Space - let R1 be the radiation from your body to Space and let R2 be the radiation from Space to your body. This...
I just calculated that the net radiation from my roof to the outside environment is 37.000 W.
To me it indicates that the throughput in the loft air is very high, and the 37.000 W does not include conduction and convection.
I used Georgia State university's online Radiation Calculator ...
I hear. Maybe the 40 C is from the heat capacity of the loft floor/1.floor ceiling. There may be 10 tons of material. The energy would stay by the 2. or 4. root of time, and tend to go up.
Now look at this...
I know it is a loose argument, but how many 2000 W electrical fans/ovens would it...
Thanks for all the good advice so far.
You are welcome to browse the pictures and drawings. They may reveal more details.
This discussion has led me to a small design change.
Originally I put the pump and the expansion tank in the loft next to the manifold to ease the water filling procedure...
Thanks. I will look at your ideas tonight.
Heres a few quick numbers:
The roof has about 250 m3 or 300 kg of air.
The air flow is estimated to 10 tons per hour because the four box fans (≈ 1 m2) could have an airspeed of 2.5 m/s. With 3600 seconds/hour and 1.2 kg/m3 it roughly equals 10...
Car radiator physics and loft physics
Thanks for all your answers about the 16 car radiators in my loft heating the swimming pool.
My question is still about car radiator physics, and less about loft physics, but I would like to comment on your suspicion that the loft temperature will drop...
Thanks. I have been worried about the temperature drop of the loft air, but i feel confident that the 100 m2 / 1000 ft2 thin metal sheets (Decra) slooping towards the sun should transfer the heat well enough.
Assume that at equilibrium the difference in temperature is 20 K and not 30 K, and the...
During summer my swimming pool is 23° C and my loft air is 53° C. (73° F / 127° F)
The sun shines on the metal roof with 1x10^5 to 1x10^6 W and I hope to move 10.000 - 20.000 W to the pool.
To move the heat down by an external water circuit to the water/water heat exchanger by the pool...