Why Is Water Flow Uneven in My DIY Pool Heater?

In summary, the person is having trouble building a pool heater using black tubing and a manifold. They noticed that only one group of spirals is getting water flow and the pressure is uneven. Another person suggests adding restrictions to the manifold to force the water to evenly flow through each group of spirals. Someone else suggests using smaller diameter tubing and using a charcoal grill to heat the water more efficiently. The original person follows the advice and successfully improves the water flow in each group.
  • #1
novop
124
0
Hi,

I'm having a problem building a sort of pool heater for my backyard. I've assembled some black tubing into 9 spirals, making 3 groups of 3, and then attaching the groups of spirals to a manifold, to supply equal pressure to each group, see pic below.

wlzn86.jpg


The water is pumped up to my roof, where the manifold is, by a pump at about 6 psi, and then the water (is supposed to) runs through the hot tubes back into the pool. The problem is this: only the group of 3 spirals on the right get water flowing through them. The other 2 groups (or 6 spirals) get no water flow.

By disconnecting the group on the left and then connecting just ONE spiral, the pressure is so weak it doesn't even flow through the one spiral. Doing the same to the middle group, I find that the water can flow through one spiral.

Shouldn't the manifold be supplying equal pressure to each group? Why is it then that the pressure on the leftmost group is very weak, the middle intermediate, and the best pressure is on the right? What can I do to improve this? Thanks in advance.
 
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  • #2
The fluid travels too fast in your manifold. When it arrives at the first group of spirals, it goes so fast and there is so little resistance to keep going forward that it takes this path instead of "turning" at the junction. Of course, once it arrives at the end of the manifold, it doesn't have a choice and it does turn into your third group of spirals.

The fluid will always take the path of least resistance, unless you force it to.

Solution:

Add restrictions. Best way would be to have the diameter of your manifold decreasing between each set of spirals (1, 2 and 3 starting from the inlet of the manifold).

Quick intuitive calculations of manifold area (Needs could vary according to the way your junctions are designed):

Ain = A1 + A2 + A3;
A1-2 = A2 + A3;
A2-3 = A3.

Otherwise, you can put some restrictions (like a valve) on section 1-2 and 2-3 of your manifold and adjust them until you get the flow characteristics you want.
 
  • #3
Thanks!
 
  • #4

And you can try the following:
On entering each group of two spiral you put one restriction,identical
This ensures equal pressure to entry for each group of two spirals,therefore equal flow.
 
  • #5
Dont know how feasible it is for you to do, but some small diameter, say 3/8-5/8" ID aluminum or copper tubing, painted black and put into a zig zagging manner would seem to be more efficient. Slower water travel would also help to heat the water a little more quickly...also, if you have a charcoal grill or wood burning grill, something to that effect, you could make something to size and it would warm it even quicker and not cost you anything really, just a couple swings of an axe and a match and lighter fluid.
 
  • #6
Thanks for the tips. I attached a valve to each entry point from the manifold and played around with the openings until I had water flow in each group. Works like a charm now =)
 

Related to Why Is Water Flow Uneven in My DIY Pool Heater?

What is the best type of pool heating system?

The best type of pool heating system will depend on your specific needs and budget. Gas heaters are typically the most popular and effective, but they can be expensive to operate. Solar heaters are a more eco-friendly and cost-effective option, but may not be as effective in colder climates. Heat pumps are also a popular choice as they are energy efficient, but may not work as well in extremely hot or cold temperatures.

How can I ensure my pool heating system is running efficiently?

Regular maintenance and cleaning is important to ensure your pool heating system is running efficiently. This includes cleaning the filter and checking for any leaks or damage. It is also important to properly insulate your pool and use a pool cover to help retain heat.

Do I need a professional to install my pool heating system?

It is recommended to have a professional install your pool heating system to ensure it is done correctly and safely. They will also be able to advise on the best type and size of heater for your specific pool.

Can I use my pool heating system year-round?

This will depend on the type of pool heating system you have and your local climate. Gas and heat pump heaters can typically be used year-round, but solar heaters may not be as effective in colder months. It is important to regularly maintain and check your system to ensure it is functioning properly.

How can I lower the cost of operating my pool heating system?

There are a few ways to lower the cost of operating your pool heating system. This includes using a pool cover to retain heat, properly insulating your pool, and making sure the system is regularly maintained and cleaned. You can also consider using a solar or heat pump heater, which are more energy efficient options.

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