The displays above show the pool water temperature, the air temperature in the open area of the pool site and the power* being collected from the two panels.  It is a live feed and the displays are updated frequently.

We use two heat sources to keep the water warm at the pool: Electricity and Sunshine.

We prefer to use sunshine because we get it free! But when there is little sunshine, we have to use the electrical heater. To save costs, we use an off-peak tariff to get the electricity overnight when it is cheaper to supply and cheaper for us to buy. It is a 36kW immersion heater that heats the flow of circulated water as it comes out of our sand filter on its way back into the pool.

So, the electrical heater is a back-up to our preferred choice: solar heating.  

The solar heating works by pumping the pool water onto the roof of the changing rooms and through hundreds of black rubber pipes that absorb the heat from the sun. The roof area is 120 square metres in total, 60 facing east, and 60 facing west. The amount of power we get this way varies with the intensity of the sunshine and this depends on time-of-day, time-of-year and cloud cover.  So, when it is cold and cloudy, we often get no heat at all. There is one pump for the east side and one for the west side.

We aim to run the pool at between 28ºC and 30ºC.  We measure the temperature of the pool and the temperature of each side of the roof and when a roof is 0.5ºC hotter than the pool we turn its pump on.  So the east pump always comes on first in the morning, they both run during the middle part of the day and the only west one runs as the evening draws in.

*We calculate the power collected from the two roof panels by multiplying the temperature rise by the flow rate.