Solar heating Dahab Style!
There are lots of ways to heat a swimming pool in Dahab but we wanted something eco friendly so that ruled out gas and electric. Our first option was a company our building contractor put us in touch with in Cairo. He sold us on the idea of a pressurised solar panel system. We weren’t entirely convinced but thought it was worth a punt. When we finally came to order the system he put the price up by over 50% because the dollar had increased in value. We couldn’t understand the logic of such an enormous price hike and so we lost complete faith in anything he had to say! It was now time to look at other options.
Option one was to get solar piping from Israel but nobody would reply to our enquiries. We then found a swimming pool company in Cairo that sold solar pods but again nobody answered the phone or replied to email enquiries.
We were now thoroughly bored of relying on any commercially available system so it was now time to look at a homemade solution, running water through piping which would be heated by the sun. So we then scoured Dahab for the toughest black hose pipe we could find. We thought 3 rolls of 50m should just about do the job. Once we got it placed on the roof in a spiral pattern we realised that we could put loads more up there. We now have just over 400m on one roof. We can double this up and do the same on the other villa roof, all on the small stairwell top, completely out of the way of the roof terrace relaxing areas.
So we are all plumbed in and ready to go, except for one thing: A PRESSURE RELIEF VALVE. The plumber didn’t quite understand what was required as he had incorporated some one-way valves but didn’t realize that a relief valve would be needed to stop the hose pipe crushing each time the system was turned off. This is caused by the pressure of the water dropping from the roof down to the swimming pool.
Now it was time to test the system. Well it worked but it wasn’t as effective as we wanted, one way to improve this was to create a greenhouse effect. In order to use up some excess empty 20L water bottles we cut them up and arranged and attached them on top of the piping with some old Bedouin fishing net.
We put out the word that we needed old water bottles and set to work with the ones we already had. We would need at least 60 bottles. One month later almost 3/4 of the roof was covered and the water wasn’t getting any hotter, even though we tried to convince ourselves that it was. We realised that there were so many gaps between the bottles that no greenhouse effect was being created. In fact, all that was happening was the bottles were getting covered in dust and so having a negative effect.
Time to bite the bullet and put a more expensive option into effect – cover it with glass. We now have a proper little greenhouse and the system works perfectly. The only slight improvement we have made is to put a timer on the pump so that the water flows for 15mins and rests for 15mins to warm up. We are not 100% sure but we think this is more efficient than a CONTINUOUS FLOW SYSTEM. We have achieved 28 degrees C in the spa pool in March and we are pretty happy with that.
The spa water does overflow into the main swimming pool and slightly heats it but phase 2 is to put the same system on the second stairwell which will lead directly into the main pool. This will be installed before next winter with the addition of 2 solar pods brought out especially from England to boost the system. Fingers crossed that we shall have a warm pool for next winter!