Our Pool Heater

[Anarita John]

Our second winter with our pool heater. We have a Fairland Pool Heater, plus a 5kw photovoltaic system, as well as a solar cover, supplied by Green Air. Last winter we swam almost every day during the mild, dry winter but this year our swims have been limited. We suffered a period of bad weather from 3rd December till the 8th, when we did not run our pool heater. The water temperature dropped from 25c to 19c but, as the outside daytime temperature was between 18c and 23c, we soon got the water temperature back up to 25c.

Our pool heater was again switched off between the 18th and 24th December. Water temperature dropped from 24c to 15c. When we switched the pool heater on again, the outside temperature ranged between 14c and 18c and it took 5 days to get the water temperature to 24c.

On the 30th December, there was complete cloud cover, high winds, heavy rain and an air temperature of 14c. I ran the heater, on 100%, for 7.5 hours and raised the water temperature from 21c to 22c. I think that the rain decreased the water temperature by 2c and usually the sun on the solar cover increases the water temperature by 1c.

During November, we swam every day, but in December, we swam for only 9 days. Last year, it was every day. Our pool heater ran from the 25th December till the 9th January. We swam from the 29th December till the 9th January, the end of our billing period.

A day of full sunshine, in mid winter will raise the pool temperature by 1c. 3 hours of operation during a sunny day usually raises the temperature by 1c.

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All figures include household use whilst the heater was on. With our net metering system, the total cost for electricity used during the day, was €39.12. Without net metering, the cost would be €259.23. For the 39 days we had our pool heater on during November, December and the beginning of January, the cost for heating our pool was €1 per day. We swam every day in November, 14 days in December and, so far, 9 days in January.

[Jim B]

We are waiting for our Heat Pump to be installed which has been delayed due to shipping delays from Korea. Presently we are using heating oil which is very expensive and will have to buy another €500 tomorrow.
We have vacuum solar panels with a small solar pump in parallel with an electric pump that circulates the water through a heat exchanger, the electric pump kicks in when the water temperature gets very hot.
We also have an electric pump that circulates hot water from the boiler directly through the heat exchanger and will modify the pipework to redirect the hot water from the Heat Pump through the Exchanger.
Green Air will be refurbishing the pool area so hopefully we'll have every sorted for the spring.

[jeba]

How big a photovoltaic device would you need to keep the water temperature above 29°C in winter at about 600 m elevation if you built a small, well insulated pool (say 3x5m and only 1.2 m deep) with a counter-current system? Any educated guesses? Is that even realistic?