Solar Power Heating for Swimming Pools
Swimming pools are an ideal application for solar water heating, as the temperature required is quite low - under 30°C. If you buy a high efficiency evacuated tube solar panel you may enjoy solar heated pool water! As you know pool heating without solar assistance is a very expensive affair, many people soon find out that buying the pool was the cheap part and a pool can become a financial millstone around the neck!
In the U.K Solar water heating can provide heat for most of the year from about March to October and contribute towards reducing heating costs outside of that period. As a rule of thumb in calculating the number of panels required aim to fit the equivalent of 25% of the pools surface area. As a rule of thumb for a 47mm 20 tube essentialspark Evacuated Solar hot water panel this equates to roughly 1 panel per 11sqm.
Square Metres are calculated by multiplying the length in metres x breadth in metres, ( I know but you would be surprised how many miscalculate, it is, as the tailor said better to measure twice then cut once!) As pool heating can be a bit hit and miss, we recommend that customers start with this 25% of surface area figure and add an extra panel or two at a later stage if they feel the need....most customers do not feel the need. If you are calculating 25% and it comes out at say 3.5 panels, always round up i.e. fit 4 panels.
Pool heating can be hit and miss due to the fact that some pools will have better or poorer insulation than others. We also recommend the use of a floating pool cover, as this dramatically reduces heat loss when the pool is not in use. It is always easier to conserve heat energy than to generate it!
The panels will carry on working and contributing in the autumn, winter and spring when the sun shines. This proven Solar hot water heating technology is therefore ideal for pools. Simply put it doesn't make economic sense not to fit them!
Don't needlessly waste money on pool heating just because you can afford to. The cost of fossil fuels is set to increase year on year with no end in sight. Obviously electricity generating utilities pass the increased cost of power generation onto the consumer. Yes that means you.
Installation is comparatively simple. Basically your desired solar hot water system will have a pressurised solar loop with a glycol water mix circulating into and out of the stainless steel heat exchanger, this is a closed circulatory loop, and the pool water (usually pumped constantly through a filter), gets diverted after the filtering process through the heat exchanger. The exchanger has inlet and outlet for chlorinated pool water and inlet and outlet for the closed solar loop. If you have chlorine you will need the stainless steel heat exchanger (this is because chlorine causes copper to corrode). Circulation of the ‘fluid’ in the pressurized solar loop is controlled by a Resol controller with heat probe to the heat exchanger and panel manifold set to your requirements, You should set the solar controller to give the maximum temperature differential possible (usually 20C).
If you don't have chlorine, you can simply put the solar panel in-line with the pool filter, so that the pump directs water through the panel before returning it to the pool. As the panel will NOT radiate heat on cold days, heat losses will be confined to your pipe runs only - so you do not necessarily need a controller, although one can be fitted, to control a 3-way solenoid valve to divert the water through the panel when the panel is hotter than the pool water.
Pipe work should be copper from solar panels to the heat exchanger, and stainless steel or plastic from the heat exchanger to the pool. The 20 tube evacuated solar panel is 2.25m2 so each panel will heat 11m2 of pool area. A 22m2 pool would only need 2 x 20 tube panels. A 44m2 pool would need 4 x 20 tube panels, A 88m2 pool would need 8 x 20 tube panel. Compare this to the cost of heating a pool for a year!
The standard components required are:
PANEL KITS, ROOF MOUNTING KITS (OFTEN FLAT ROOF ‘A’ FRAME TYPE), HEAT EXCHANGER, PRESSURIZED SYSTEM KIT, ANTIFREEZE, PUMP (SIZE OF PUMP DEPENDS ON POOL SIZE), RESOL CONTROLLER WITH TEMPERATURE PROBES FOR PANEL AND HEAT EXCHANGER.
Plumbing and pipe work to be sourced locally by the customer, not supplied.
Flat Plates and Plastic Pipework
Flat plate collectors only provide a useful amount of heat during the summer months in the UK. due to their high heat losses during cold or windy weather. When the ambient temperature drops, the heat loss can easily exceed the heat gain - turning your flat plate solar collector into a radiator! The reason for the popularity of flat plate collectors is their cheap construction - you can build one yourself for a few pounds worth of scrap material, or you can buy one for £300-500. This is typically a lot cheaper than evacuated tube panels, which typically cost £800-1200.......until now! Don't fit a dinosaur!
Vacuum tube collectors will provide useful heat for 12months of the year, as long as the sun is shining, and can even produce heat in overcast weather. (In April, an overcast day without any sunshine is still able to heat a 210litre hot water cylinder to 40°C)
There are some flat plate systems for sale in the UK, such as the Solar Twin system, which use plastic pipework to make installation easier and to reduce costs. Whereas this pipework may be ideal for flat plates, it is definitely not adequate for evacuated tubes. On a hot sunny day, flat plates may heat water up to a temperature of 60°C. Evacuated tube systems are capable of heating the water beyond 140°C. Most plastic pipework is able to stand no more than 90°C - so you should always use copper for solar installations.
Disadvantages of Solar Heating
We can't find any disadvantages other than if for some crazy reason you like being lead by the nose by your energy supplier, with no control or influence down a one way street, from one energy price rise to another. You can minimise the impact of this cyclical effect and offset. You will be empowered! ( We don't think anyone likes another business, person or party to have a detrimental effect on their wealth, do you? As Jonesy would say "They don't like it up em!" We all know they can dish it out but can they take it?)
