sizing water pump

[trkinlv]

hi, i have an old solar water heater panel and i want to make a pool water heater out of it . any ideas about the size of the pump?

[Mike90250]

Just a small taco pump should do it. You don't need a lot of pressure, just enough to get the water flowing.

[trkinlv]

i solved the pump question, but you mentioned that at forty sq ft my panel wasnt big enough. how much do i need/

[Mike90250]

Generally, "they" say 50% of the pool surface area. Other wise, you cannot keep up with the nighttime losses.

[MarineLiner]

i solved the pump question,
but you mentioned that at forty sq ft my panel wasnt big enough.
how much do i need/

Which pump is it?
There are two kind of panels now:
- Solar water heater panel.
- Solar electric panel for the pump.

[Jbergess]

i solved the pump question, but you mentioned that at forty sq ft my panel wasnt big enough. how much do i need/

Hi Trkinlv,

You need to figure out how much heat your pool looses on a daily basis. The formula for this is:

Heat Loss (Per hour) = (Surface heat loss factor)(Temperature Difference)(Surface Area)

To make this simpler, your surface heat loss factor for sheltered positions with an average wind velocity of 3mph would mean about 5 Btu loss per hour per square foot.

The temperature difference, or Delta, is simply taking the average low temperature of the air around the pool (during the season you wish to heat the pool) and subtracting it from the temperature you want the pool to be at. For example, if the outside air on average at night during heating season is 60F, and you want the pool to stay at 70F, this is a 10F delta.

Then, take the above two numbers and multiply them together along with the area of the pool. Therefore, your formula should look something like this:

Heat Loss = 400sf x 5Btu x 10F
Heat Loss = 2000Btu/Hr

So, you would need 48000 Btu/Day to maintain the temperature of a very small, 20' x 20' pool.

This is, however, different than the BTUs needed to initially heat up the pool from the winter season, but it's a good place to start.

This site has a lot of good formulas to help as well:

http://www.engineeringtoolbox.com/swimming-pool-heating-d_878.html

Hope this helps!