Solar heating system not heating

[GerardoChile]

Hi All, regards from Chile.
I have some solar panels in my roof, total of 107sqft. for a 17m3 pool. They are installed "horizontally" on a 30º roof pointing directly to the North ( I am in the south hemisphere ). I have a vacuum valve that works perfect when the system shuts down and I have no leaks at all. I have also a check valve after the filter. The filter is a Vulcano VC50 with a 1HP pump from Vulcano as well. The system seems to work pretty fine, it throws a lot of air into the pool for 30 secs when starts, then goes with the water coming from the panels and no bubbles, but the water is "almost" at the same temperature of the pool. I kinda feel no difference at all in the temp between the water going into the panels and coming out from them and I have a metal roof at 86ºF. Is this normal? I mean the water is not even near warm. Maybe is it because the panels are "horizontal" on the roof and have some air that is not released? Maybe is it because the flow of the system is so hi? Do I have to control the speed of the motor and or add more panels? I attached a pic of the system, the motor and the panels box. I really appreciate your feedback since I have no clue about what is going on and no one in my town has been able to help me. Thank you very much in advance.

 

[JohnT]

Welcome to TFP!

There should be only a very small difference between inlet and outlet temperature on solar panels.The panels are much more efficient that way.

The easiest way to check the panels for proper operation is to put your hand on them while they are in direct sun on a hot day. The panels should be cool to the touch which indicates the water flowing through them is removing the heat from the sun.

 

[GerardoChile]

Hello JohnT, thanks for the welcome and for your answer.
As far as I get you, they are working just fine so I have to maybe put them flowing more hours a day to get more heat on the pool?
Regards.

 

[JohnT]

Hello JohnT, thanks for the welcome and for your answer.
As far as I get you, they are working just fine so I have to maybe put them flowing more hours a day to get more heat on the pool?
Regards.

Probably so. Using a solar blanket, especially at night, helps to keep the heat in the pool giving you warmer water than just the panels.

 

[borjis]

That seems a bit odd. If the panels are in direct sunlight on hot sunny day, the water in the returns, should feel warm.
At least that is how the system worked at my first house/pool with solar. On a 90 degree day, the water output from
the panels was usually around 8 degrees warmer. (the system had temp gauges for incoming /outgoing water temp).

 

[Tres Gatos]

I don't under want you meant by 17m3 pool? What is the surface sq. ft. and average depth? 107 sq. ft. for a solar array may be too small ideally it should be about the same sq. ft. as your pool. It does sound like your pump speed is too high for such a small array. The difference between inlet and outlet pipes should be about 4 degrees for maximum efficiency. Trying using an infrared thermometer to measure the difference.

 

[setsailsoon]

G,

Welcome to TFP!

Most panels are designed to flow from the bottom up. This way each tube fills completely from the bottom up You may be "short circuiting" your flow with horizontal installation. What is the temperature where you are during the day. I currently have the readings below with 84 deg F air temp. Just to decode the readings, the outlet of my collector is 96 deg F. This drops to about 90 when sun goes behind a cloud. My pool is 86 deg. Set point is 92, This time of year I never get to 92. During summer it would get much higher except the controller keeps the solar bypass open to prevent pool from getting too hot.

Also, for comparison I have 9.5 4'X12' panels for my 12,800 gal pool. The panel area looks too small for your pool that is 4600 gal (17.3 cu meters is your volume, correct?) but this depends a lot on your specific location. That said your outlet temp should be much higher in sunny weather.

I hope this helps.

Chris