Select to expand quote
Chris 249 said..boofta said..
There you go Chris, now you have deduced how black plastic tubing can absorb less heat from the sun over time
God help you, and all your crazy believers zealots
Did you also miss the part where FN pointed out that the smoke and haze has reduced the efficiency of solar systems this summer, as noted here;
....
It's not a deduction to say that smoke and haze have reduced the efficiency of solar systems this summer, it's a fact. Therefore if your pool is cooler than usual it is highly likely to be because your solar heating is not working as well. And of course, the idea that people should discard scientific measurements of the entire globe in favour of one person's memories of the temperatures of one swimming pool is bizarre indeed. It seems to show an amazing degree of egocentric thinking.
In my case at least, I saw the effect of this personally, which is why I brought it up. I have a system with 2 flate plate collectors, 2 pumps, and 2 storage tanks. Each has thermistors on the collectors and the tanks and you can see the rise in the temperatures as the collectors come up to temp and then the drop in temp as the pumps circulate the water, as well as the tank temperature levels. My system polls every 2 seconds so you can see exactly what is happening.
It is quite apparent on a nice summer day, when it is clear, that the collector temps go up quickly, and then the pump cycles. In summer it easily gets the tanks up to temp, but when you see clouds come over, the input drops dramatically. You can 'see' the clouds come over the collectors just by looking at the logging data.
On the hazy days from the bushfire smoke, I was a little bit surprised that the solar input was much lower and barely cycled the pumps. I think the vacuum tubes are meant to be better than flat plates in their ability to pick up indirect solar energy, but I just don't think there is much there to be had when there is cloud cover, or in this case smoke haze.
Anyone know about photovoltaics and cloud cover? I think I remember that it wasn't as bad as with solar hot water systems in its ability to get useful energy.
Edit: I just read Chris' links and they are talking about photovoltaics. Based on what I saw, I wouldn't be surprised if the energy lost on smokey days was more than 45% as from what I saw it seemed much less.
I guess with a pool for thermal mass it would take a while to change that temperature above ambient, and I am wondering if the loss of energy on the cool days is just not getting replenished enough to see the pool temp increase.
Either way, I think we have refuted the idea that a solar pool heater is a good indicator of global warming or cooling.