Which would heat better?

[GB]

Here is a question for you physics or thermodynamics people out there.

I have an inground swimming pool and I am trying to figure out which method would heat the water better. The two options are:

1. have the pump on during the day. The sun heats the water and the water is continuously circulating.

2. Have the pump off during the day. The water is relatively still while the sun heats the water, then turn the pump on at night and circulate after it has been heating all day.

Would one way heat faster or hotter than the other?

 

[Adam14]

I really don't know for sure, but if you think about it in a cooking mindset: mechanical convection - stirring helps distribute heat. Going with that theory, the pump on should work better.

If you left the pump off, the top of the water would heat, and a little below from conduction, but that water would come to a stand still at how hot it will get. All the water below would remain cool. Turning the pump on then would probably not have that much of an effect on the water. But, like I said, I really don't know.

 

[GB]

I was thinking the same Adam, but then I thought that with such a large volume of water and such poor conductivity maybe it would be better to have the water stationary so that it has time to heat. If the pump is on and the water is circulating does it give the water on top enough time to heat up and distribute that heat? I can see both sides of the coin, but really don't know the answer.

 

[Adam14]

hhmmm, you bring up a good point - would the water have enough time to heat. I'd pay a neighbour's kid to hang out and turn the pump on and off every half hour

 

[Andy M.]

I suspect running the pump will give you more evenly heated water than not.

The sun is providing the heat either way so there wouldn't be a difference in which method will heat faster.

 

[GB]

The sun is providing the heat either way

Yeah I guess that would be the key.

 

[roadfix]

You can meanwhile cover your pool with some kind of a heat absorbing solar material to capture heat....?

 

[GB]

I actually did have a solar cover roadfix, but they only last so long before they breakdown (which I did not realize). They are also a pain to use, but they do work as long as you have sun. We have not had much sun this summer at all unfortunately.

 

[bourbon]

I would think the water circulating would lose heat as it traveled through the piping. Much like a radiator draws heat off water as it passes through. But that's only a guess

 

[CasperImproved]

I would think the water circulating would lose heat as it traveled through the piping. Much like a radiator draws heat off water as it passes through. But that's only a guess

Now you are bringing up the whole thermostat thing If the water travels fast enough, the heat will dissipate quicker.

I would go with the turn the pump on during the day, just not all the time.

Of course, I reserve judgment in case an energy engineer comes online with an opinion.

Bob