Designing and Building a Solar Powered/Controlled Swimming Pool - Part 1

Designing and Building a Solar Powered/Controlled Swimming Pool - Part 1

We live in a totally off-grid solar powered home - no electricity from any utility. Just panels, an inverter and batteries.

We decided we wanted to put a pool in our yard. But how can it be done without switching over to that electrical utility. Pool pumps and filter systems are power hungry. Well, why not solar?

Time to do some research! Pool suppliers and local pool contractors are no help. Okay, onto the internet.

Search for solar powered pumps. There's lots of them but they are just regular type pumps reconfigured, and they are expensive. The pump ist the most critical part, you have to keep the water circulating or it stagnates and you get that nasty green algae. But you don't need 1500 watts of power usage to circulate water. Then I found it. A company called Laing Thermotech makes a small circulating pump designed for direct connection to a photovoltaic cell (solar panel) When the sun shines the pump runs.

Next, a filter. We opted for an ultraviolet light system. Runs on AC power and that meant we would need to install an inverter. UV lights kill many nasty water borne things and reduces the dependency on chemicals, but it does nothing for dirt and small particles which are removed by the traditional pool filter.  So that was only half a solution. The other half came later.

Nothing special about the pool construction. We decided on cement filled hollow block and lots of rebar. (Nicaragua is very seismically active.) Beside the pool we built a block 'box' to contain the plumbing connections, the pump, the UV light, and the inverter plus a solar charge controller and a single deep cycle 12 volt battery. The roof of the box is a 200 watt solar panel.

Electrical connections : 

  1. the solar panel is connected to the charge controller
  2. the charge controller is connected to the inverter and the battery
  3. the inverter is connected to the battery
  4. the UV light is plugged into the inverter and, with a small timer, runs 5 hours per day

This configuration allows the pump to run constantly 24 hours a day. The panel is charging the battery and the battery is powering the pump - and the UV light.

In Part 2 :

  1. the filter system
  2. maintenance