Undergrad Pool Siphon: Can Circular Loop Work?

[anthonybommarito1]

I have a pool that's about 5ft deep in the middle and I wanted to use a siphon to possibly heat my pool. Essentially my idea was to use a black hose, have it submerged about a ft or so in the pool run it out onto the deck where it could be heated and then back into the pool where the other end was submerged say 5ft... Would this siphon be able to work if it essentially ran in a circular loop back into the pool just at a greater depth?

 

[Buzz Bloom]

Hi anthony:

A siphon works to move a liquid from a place where its surface is higher to a place where the surface is lower. To move in the reverse direction you need a pump.

You seem to want to move a liquid from a height which is below the surface of the liquid to a deeper height in the same pool. (While moving the liquid you want it to become warmed.) A siphon cannot do that. Imagine putting a four foot hollow pipe between one foot below the surface of a pool to five feet below the surface. Why should this move any water?

Hope this helps.

Regards,
Buzz

 

[sophiecentaur]

Your idea could work as a 'thermosyphon' which was the system used in old central heating systems and for early car cooling (before pumps were introduced). If you have an inverted U with the heat source (solar heat exchanger) in one leg, you can induce some convection. Unfortunately, the convection does not work very effectively to transfer heat from the heater to the pool when the heat source is above the pool level. If your garden has a place that's lower than the pool surface, a thermal collector could produce better convection and a higher rate of heating.
A basic problem here, though. If the area of your thermal collector is less than the pool area, it will only be collecting a pro-rata amount of heat compared with what the pool's (100m², perhaps) area is getting from the Sun, anyway.
A common technique is to cover the pool with a transparent, insulating sheet (bubble wrap type of thing). If you only uncover the pool when you want to use it, you get the benefit of several hundred Watts of solar power for every square metre of pool surface.
Cheapest way to be warm when swimming could be to wear a wet suit.