Paphos Life

Now is the time many people realize that their Cypriot Solar hot-water system gives not enough hot water and needs always costly electric boost through the electric coil. This can happen if the system is old or of very poor quality. (or no sunshine )

Green Air Paphos decided to import the most efficient Thermosiphon system on the market from Germany and having it in stock at the moment.
https://www.paphoslife.com/directory/entry/greenair

Beside the efficiency through high performing panels and good insulation of the tank there is another very important feature: built-in overheat protection. It limits the maximum temperature in the tank to 85c which means no scaling of valves no system failures from lost solar liquid,
no lost drinking water from overheat blow-off. (which is the reason of many problems with this systems here in Cyprus!)

Here a very informative file from Wagner Solar Germany with all the technical details etc...

https://docs.google.com/viewerng/viewer ... cuterm.pdf

Max

I find that in many cases the lack of hot water is due to the low capacity of installed hot water tanks on the roof connected to the solar panel system so that once you draw off a tankful through the day all you are left with is a tank full of cold water with a limited time for it to heat up before sunset.

Varky wrote: ↑Thu Jan 02, 2020 5:58 pm I find that in many cases the lack of hot water is due to the low capacity of installed hot water tanks on the roof connected to the solar panel system so that once you draw off a tankful through the day all you are left with is a tank full of cold water with a limited time for it to heat up before sunset.

You are right Varky. The size of the imported hot water tanks from Wagner Solar is 200 l with one panel and 300 l with 2 panels. Further very important is the 60 degree tilt of the panels for the Nov-Feb sun on a flat roof.

Max

The worst factor is that cheapo HW tanks have poor thermal insulation. I had a good tank that provided adequate hot water, even in the most of winter. The installers of our CH system replaced it with cheapo rubbish because the good tank didn't have the exchanger coil. Result: almost no HW in winter months, even in good sunlight conditions. BTW, our panels are set at 60-65° to get best winter results. Our neighbours have queried it but stay at ~25°, losing winter HW. Their problem if their heating bills are higher than optimum.

Devil wrote: ↑Thu Jan 02, 2020 6:49 pm The worst factor is that cheapo HW tanks have poor thermal insulation. I had a good tank that provided adequate hot water, even in the most of winter. The installers of our CH system replaced it with cheapo rubbish because the good tank didn't have the exchanger coil. Result: almost no HW in winter months, even in good sunlight conditions. BTW, our panels are set at 60-65° to get best winter results. Our neighbours have queried it but stay at ~25°, losing winter HW. Their problem if their heating bills are higher than optimum.

I copy and paste the explanation from Wagner Solar concerning tank insulation of their product:

"Excellent insulation:
Aside from the safety tests, the institute scheduled an
additional examination of the system‘s thermal behavior
at night. Thermo-graphic infrared images confirmed the
exceptional insulation standard, especially also of the pipe
connections.
SECUterm does not suffer from reverse nighttime heat
flows that could lead to heat losses from storage to collec-
tor. In this design the return pipe is integrated within the
collector, thus always having the same temperature as the
solar absorber."

Interesting for me the last section, concerning reverse nighttime heat flows back to the panel, which could lead to a huge loss of hot water temperature.

Max

cyprusmax47 wrote: ↑Fri Jan 03, 2020 10:36 am Thermo-graphic infrared images confirmed the
exceptional insulation standard, especially also of the pipe
connections.

Max

Interesting point about the pipe connections. This is often overlooked. How often do you see massive lumps of brass connectors/taps next to the hot tank, without a milligram of insulation? As I write this, I can see our neighbour's HW tank with a naked brass tap on the outlet with ~5 cm of naked pipe coming out of it (OK, his whole installation is ludicrous, but that's another story!).

When I think of the naked brass pipes running underground from the furnace 10 m away to the radiators it makes me cringe.

jeba wrote: ↑Fri Jan 03, 2020 9:18 pm When I think of the naked brass pipes running underground from the furnace 10 m away to the radiators it makes me cringe.

The copper pipes usually used (haven't heard of brass used for that) come with integral poor insulation. A very small part (~1½ m) of our CH system is outside but the installers put on thick extra foam insulation. All the other pipework is indoors in channels, so heat losses form part of the heating, complementing the radiators. If only the outside walls were insulated!!!!