Sun May 23, 2021 10:30 am
#1848685
Energy saving is not as easy as it seems. I wonder about the maintenance costs of PV panels and their associated circuitry.
I have been using thermal solar panels for 40 years and at my latitude (44°N) we have free hot water for 8-9 months of the year. The initial installation cost was high, but was probably amortised within 10 years. Maintenance is not negligible. I had to pay a roofïng contractor a significant sum to change the panels for newer more efficient ones (they are too heavy for me to get on and off the roof) and now the problem is too much hot water in the summer. The water temperature often rises above the thermal cutoff for the water heater and when the winter comes round I wonder why the resistance heater is not working. Just have to take the cover off and poke the reset button with a screwdriver.
The other problem is frost. The primary circuit has antifreeze in it, but over the years due to leakage this becomes diluted. It is not a trivial task to top up with antifreeze as it means climbing on to the roof and having a helper drain out a bit while filling from a a funnel.
For the moment I get round the over heating and over cooling by running the circulating pump continuously in very hot and very cold weather. The resistance heater is controlled automatically by a microcontroller board with a real time clock. It has worked 24/7 for 25 years and the RTC still keeps good time, long may it last. The only problem is that altering the program or the date requires hook up to a laptop with a serial port. My last one gave up the ghost this year.
Simon
I have been using thermal solar panels for 40 years and at my latitude (44°N) we have free hot water for 8-9 months of the year. The initial installation cost was high, but was probably amortised within 10 years. Maintenance is not negligible. I had to pay a roofïng contractor a significant sum to change the panels for newer more efficient ones (they are too heavy for me to get on and off the roof) and now the problem is too much hot water in the summer. The water temperature often rises above the thermal cutoff for the water heater and when the winter comes round I wonder why the resistance heater is not working. Just have to take the cover off and poke the reset button with a screwdriver.
The other problem is frost. The primary circuit has antifreeze in it, but over the years due to leakage this becomes diluted. It is not a trivial task to top up with antifreeze as it means climbing on to the roof and having a helper drain out a bit while filling from a a funnel.
For the moment I get round the over heating and over cooling by running the circulating pump continuously in very hot and very cold weather. The resistance heater is controlled automatically by a microcontroller board with a real time clock. It has worked 24/7 for 25 years and the RTC still keeps good time, long may it last. The only problem is that altering the program or the date requires hook up to a laptop with a serial port. My last one gave up the ghost this year.
Simon
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