Community Pool Solar

So, to get an idea of what was actually happening I contacted Nigel Palmer of TinyTag data loggers for some help. Nigel very kindly provided 4 data loggers for us to track air temperature, water temperature, boiler activity and sun activity.  The loggers were set up to all start at the same time and sample every 5 minutes for a week.  The data was then downloaded and overlaid to get an idea of what was happening.  Notes were made about the weather conditions but you can see from the plots that it's clear to see when the sun was out.  The loggers were run four times, each time with different weather conditions.  From the data collected we quickly saw that indeed the pool was not requiring any boiler input on sunny days to maintain a temperature of 28C.  We also got a good indication that we could expect a 0.5C drop in temperature in less than ideal conditions (increasingly common it seems for a UK summer).

This information has given us enough confidence to step out of the normal practice for solar pool heating and specify glazed flat panels to heat our pool.  This option is both more complex and more expensive but gives us three key advantages which actually make installing a solar system worthwhile in the first place.  Most importantly, the panels will collect heat in conditions that are less than perfect.  In prolonged sunny conditions the higher specified panels are able to heat the water to a higher temperature allowing us to use the pool water as a thermal store.  We don't really want to heat above 31C as this would be too warm for lane swimmers but at 3 degrees above the target temperature of 28C and with 0.5C drop per day we effectively give ourselves a 6 day buffer from very poor weather (in theory).  The system also allows a greater degree of control allowing us to fine tune the water temperature with experience - balancing performance against user comfort.  We will also be installing systems to track performance and benefit so hopefully next year at this time I will be able to report how theory matches reality.  Simulations suggest that we will have a 60% input from the solar saving 5 tonnes of CO2 per year - let's see what actually happens.

A special thank you to Nigel Palmer for supporting this project - TinyTag data loggers were a joy to use.

www.geminidataloggers.com