I have been researching solar heaters and I keep seeing comments along the lines that the system will increase temperature 1 degree per day, or 5 degrees in 5 days, etc.. Am I missing something? That seems like a very insignificant increase?
Solar Heaters Temp Increase
- Thread starter BobnAmyG
- Start date
borjis
LifeTime Supporter
I had a nice setup at my previous home. With south facing roof panels. On a clear sunny July day, the temp gauge on the return always showed an 8 degree increase. It depends on a few factors but this 8 degree increase on return water temp is fairly common on a good setup. Only 1 degree a day rise doesn't make any sense unless it's cloudy outside.
I think we are talking about two different things. The increase in temperature of the water going into the solars and the water coming out (10-15 degrees) and the total increase in the temperature of the pool water. The one dgree rise is referring to the actual increase in the pool water. One degree per day seems so low as to not be worth the cost?
borjis
LifeTime Supporter
I'm not sure who said it, but it's not true unless the setup was wrong. On a hot sunny day they work about as good as any mid-range pool heater. I had to not use the solar in August because it got too warm. A proper setup will absolutely heat the entire pool more than 1 degree in a day, running afternoon to sunset.
Of course on cloudy days, all bets are off.
Of course on cloudy days, all bets are off.
- May 3, 2007
- 17,000
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
There are a lot of factors which determine the heat gain into the pool. But heat retention is just as important if not more so. A solar cover will allow you to keep a good percentage of the added heat so it can accumulate over a few days. But as the heat rises in the water, the heat loss, cover or not, will also increase and at some point, the pool will not get any hotter.
In general, the inlet to outlet temperature of the solar panel should not exceed 5F or efficiency will suffer. If you keep the flow rate in the panels above 0.1 GPM/sqft, the differential temperature should be below 5F and efficiency should be above 80%. Contrary to popular belief, you want high flow rates and low temperatures out of a panel instead of the opposite. This maximizes heat transfer into the pool.
The actual heat gain you will experience will depend on the volume of your pool and the square area of the solar panels, plus a lot of other factors that relate to the heat loss (evaporation, radiation, convection, conduction). There are ways to estimate the amount of heat gain in a pool but I would need to know the volume and surface area of your pool. Also, the panel size you are considering and the pool's current temperature. Everything else can be determined from your location.
borjis
LifeTime Supporter
Oh ya forgot that very important part....you do need a bubble cover to ensure keeping as much heat in as possible. In my region heating would be about useless without one.
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