Are you all pleased with your solar panels for hot water heating

Jakey Rolling

championc wrote: »

So from Jakey's system, how many degrees could the whole of 300 litres have been raised on the 25th ? So if the whole tank was at 24 deg, could the whole 300 litres have been increased to 45 deg ?

Sensor is at mid tank level, hence why I assumed 150 litres in my ballpark calculation.

Suits me that I didn't have to use oil to heat the tank for evening use on near the shortest day of the year. Concerns remain over excessive stagnation in summer.

John T Carroll

championc wrote: »

So from Jakey's system, how many degrees could the whole of 300 litres have been raised on the 25th ? So if the whole tank was at 24 deg, could the whole 300 litres have been increased to 45 deg ?

As long as the upper150 Litres of the cylinder remained above 45C then the solar system would only heat the bottom 150 Litres. To heat the whole 300 litres from 24C to 45C would have required Solar Radiation of 1145 joules/cm2 based on your system efficiency of 71.29% on 24th Dec.. To heat 150 Litres from 24C to 45C required Solar Radiation of 572 joules/cm2 again based on your system. The highest December Roches Point Solar Radiation that I have recorded over the past four years was 519 joules/cm2 in 2013. So there is no way, in my opinion, that one could heat 300 Litres from 24C to 45C and nobody has claimed that they could. Raising 150 Litres from 24C to 45C was/is certainly feasible in my opinion and because of the parabolic 30 tube array probably did not require the theoretical 572 joules/cm2. It is still an outstanding performance though from any system.

Bscan86

Hi,
I was talking to a lecturer on energy efficiency and he maintains that it takes over 10 years to pay back. Does anyone else know is this accurate and how much money do they actually save????

Bscan86

Bscan86 wrote: »

Hi,
I was talking to a lecturer on energy efficiency and he maintains that it takes over 10 years to pay back. Does anyone else know is this accurate and how much money do they actually save????

It really depends on how much you pay for the system in the first place, for example a home made set of collectors made from junk will return in less than a year while a custom made system using specialist equipment may never pay back. The other variable to factor in is the cost of the fuel the solar is supposed to displace.

championc

I paid for €5k for my system a few years ago. I monitor my bills for gas and I went from nearly 6 units per day to about 4. My usage will lead to a payback in about 9 years at current prices

lazeedaisy

Bscan86 wrote: »

Hi,
I was talking to a lecturer on energy efficiency and he maintains that it takes over 10 years to pay back. Does anyone else know is this accurate and how much money do they actually save????

I had a friend who said the same, for a retro fit

We put them in a new house, it's a passive house, and in 18 months it's cost us 300 in oil, and our elec. bills are very low.

We have 5 panels, and the weather in the last 4 or 5 days has been the worst I have ever seen, very little sun as opposed to 1 week ago the heat was coming in at 58degrees,

We have a stove, and I put a large kettle on it every evening which is used to wash the dishes, I am mindful if there has not been much sun, and work around it. Have not needed to turn the oil on to heat water yet this year,

josip

We paid €3300 for our system 4 years ago.
Payback time will be around 11 years.
But each time maintainence is needed, eg. air in the fluid, that gets pushed back further.
Pretty much as we expected apart from the maintainence

dr.fuzzenstein

Hi, I don't have a solar system yet, but can you tell me what you think about this:

http://www.ravensbergersolar.de/solarkollektoren/roehrenkollektoren/8/ravensberger-high-energy-3000-30-roehren-bafa-foerderfaehig

How good/bad can it be at that price, considering the average Irish price is the same but with an extra 0 at the end?

dr.fuzzenstein

dr.fuzzenstein wrote: »

Hi, I don't have a solar system yet, but can you tell me what you think about this:

http://www.ravensbergersolar.de/solarkollektoren/roehrenkollektoren/8/ravensberger-high-energy-3000-30-roehren-bafa-foerderfaehig

How good/bad can it be at that price, considering the average Irish price is the same but with an extra 0 at the end?

At first glance they look similar to the ones that Navitron sell, as for the missing zero, this is a DIY install and you still have to buy all the mountings, plumbing, pumps and controller.

dr.fuzzenstein

Deleted User wrote: »

At first glance they look similar to the ones that Navitron sell, as for the missing zero, this is a DIY install and you still have to buy all the mountings, plumbing, pumps and controller.

Makes sense, I'll check it out. I think they have all that stuff too.
Is there a handy guide or suggested reading for installing one of those?
I do know Navitron, for obvious reasons right now is better to buy on a € website, rather than a £ website.

dvdman1

Solar panels need maintance and can get damaged in high winds..if their on the house for years what do you think the chances of damage even vandalusm are?
They seem unviable compared to solid fuel substituting oil/gas

dvdman1

dvdman1 wrote: »

Solar panels need maintance and can get damaged in high winds..if their on the house for years what do you think the chances of damage even vandalusm are?
They seem unviable compared to solid fuel substituting oil/gas

Depends on the location and the standard of the installation, well installed panels shouldn't be affected by high wind. My panels have only been up since last Autumn so too early to tell about the quality of the fitting, as for vandalism, my football mad son is the biggest risk (he's been warned!).
Their running costs are far lower than fossil fuels, all you have are the pumps and on some systems are completely passive.

SpaceTime

How often do they need to be cleaned? Our roof is very high and they'd be quite inaccessible. It'd be handy if you could get self cleaning panels.

Qualitymark

SpaceTime wrote: »

How often do they need to be cleaned? Our roof is very high and they'd be quite inaccessible. It'd be handy if you could get self cleaning panels.

They don't have to be on the roof; I've seen them on garage rooves.

josip

SpaceTime wrote: »

How often do they need to be cleaned? Our roof is very high and they'd be quite inaccessible. It'd be handy if you could get self cleaning panels.

Depends on their location and installation angle.
Most of the ordinary atmospheric dust will get blown off/washed off over time in my experience.
If you have trees nearby then the sap from those can build up and should take steps to clean that off, the same as you would a car.
I haven't measured but the amount of dust/dirt I clean off them is almost the same regardless of whether it's 3 months or 2 years between cleanings.
And the amount of it wouldn't affect them by more than 10-15% in my layman's opinion

Palmach

Deleted User wrote: »

some systems are completely passive.

When you say passive do you mean no electricity required? I am interested in installing panels so would like to know. Thanks.

John T Carroll

josip wrote: »

Depends on their location and installation angle.
Most of the ordinary atmospheric dust will get blown off/washed off over time in my experience.
If you have trees nearby then the sap from those can build up and should take steps to clean that off, the same as you would a car.
I haven't measured but the amount of dust/dirt I clean off them is almost the same regardless of whether it's 3 months or 2 years between cleanings.
And the amount of it wouldn't affect them by more than 10-15% in my layman's opinion

Have no real problems with dust/dirt but once or twice a year either a starling or a blackbird decides to use just one (always the same one) of my panels as a toilet, luckily I have a velux window in my converted attic and I have a hose connected to the mains water, so I just throw a few buckets of sudsy water over the panels and wash them off with the hose, a shotgun might provide a more permanent solution.

dr.fuzzenstein

John T Carroll wrote: »

Have no real problems with dust/dirt but once or twice a year either a starling or a blackbird decides to use just one (always the same one) of my panels as a toilet, luckily I have a velux window in my converted attic and I have a hose connected to the mains water, so I just throw a few buckets of sudsy water over the panels and wash them off with the hose, a shotgun might provide a more permanent solution.

I don't think a shotgun is a recommended method for cleaning solar panels.

SpaceTime

dr.fuzzenstein wrote: »

I don't think a shotgun is a recommended method for cleaning solar panels.

That's why you shouldn't read Texan eco-heating websites!

John T Carroll

dr.fuzzenstein wrote: »

I don't think a shotgun is a recommended method for cleaning solar panels.

No, but its generally lethal when discharged at a small bird from a distance of six feet and should also remove any heavy deposits from the panel.....OK, I promise not to try it.

Palmach

Palmach wrote: »

When you say passive do you mean no electricity required? I am interested in installing panels so would like to know. Thanks.

Yes, basically if you have the tank located such that the top of the panel is level with the top of the tank and likewise the bottom is level between the tank and the panel.

The system will work purely on the fact that hot water rises and the heat will "lift" the heated water into the tank drawing cold in behind it.

It works well on flat panels (never heard of anyone using this method with tubes).

josip

Deleted User wrote: »

Yes, basically if you have the tank located such that the top of the panel is level with the top of the tank and likewise the bottom is level between the tank and the panel.

The system will work purely on the fact that hot water rises and the heat will "lift" the heated water into the tank drawing cold in behind it.

It works well on flat panels (never heard of anyone using this method with tubes).

Since the vast majority of tubes are roof mounted, and the majority of attic water tanks are situated closer to attic floor level, a pump is needed.

These are very common in southern Europe and elsewhere and are a much cheaper solution relying on water convection

dr.fuzzenstein

Deleted User wrote: »

Yes, basically if you have the tank located such that the top of the panel is level with the top of the tank and likewise the bottom is level between the tank and the panel.

The system will work purely on the fact that hot water rises and the heat will "lift" the heated water into the tank drawing cold in behind it.

It works well on flat panels (never heard of anyone using this method with tubes).

Speaking of panel and tank location, I'm in a bit of a pickle.
My hot water tank is in the middle of a fairly long house, but the solar panels will have to go on the south gable end for ease of installation and aesthetic reasons, otherwise I would have to make them south facing on an east or west facing roof and that would just look horrible and ruin the roofline of the house.
I'm not quite sure about the exact distance, but more than 20 meters in any case.
Question:
What sort of distance from panel to tank is too far? Can I make up for it with using better insulation round the pipe? Will I need an uprated pump? Will Darth Vader be in the new Star Wars movie? Any answer appreciated!

josip

dr.fuzzenstein wrote: »

Speaking of panel and tank location, I'm in a bit of a pickle.
My hot water tank is in the middle of a fairly long house, but the solar panels will have to go on the south gable end for ease of installation and aesthetic reasons, otherwise I would have to make them south facing on an east or west facing roof and that would just look horrible and ruin the roofline of the house.
I'm not quite sure about the exact distance, but more than 20 meters in any case.
Question:
What sort of distance from panel to tank is too far? Can I make up for it with using better insulation round the pipe? Will I need an uprated pump? Will Darth Vader be in the new Star Wars movie? Any answer appreciated!

I'm not sure about 20m but we had the opposite, related, problem originally.
Our panels were only 1-2m from the water cylinder with the pump sitting between them. We didn't have a heat dump.
When we went away for the first summer holidays, the panels got to setback temp (around 220 deg I think) and although the fluid wasn't circulating, the heat travelled down the pipe by conduction and burnt out the pump according to our installer.
He then put in an extra 10m of piping to prevent this happening in the future. It hasn't and there hasn't been a noticeable degradation in performance.
So you'd definitely be ok with 10m. Can't say for 20m.
It is rumoured that Darth will make a cameo appearance

a postere

sinnerboy wrote: »

I'll sticky this awhile and add

Please indicate

cost
year of installation
m2 area
orientation
flat plate or tubes
cylinder size
summer heat dump strategy ( if any )

Reminder - no trade / company names please

.

I'd love to see money saved by going solar added to this list

freddyuk

dr.fuzzenstein wrote: »

Speaking of panel and tank location, I'm in a bit of a pickle.
My hot water tank is in the middle of a fairly long house, but the solar panels will have to go on the south gable end for ease of installation and aesthetic reasons, otherwise I would have to make them south facing on an east or west facing roof and that would just look horrible and ruin the roofline of the house.
I'm not quite sure about the exact distance, but more than 20 meters in any case.
Question:
What sort of distance from panel to tank is too far? Can I make up for it with using better insulation round the pipe? Will I need an uprated pump? Will Darth Vader be in the new Star Wars movie? Any answer appreciated!

You could have East/West installation? Perfectly acceptable method.
20 metres is no problem at all.

freddyuk

josip wrote: »

I'm not sure about 20m but we had the opposite, related, problem originally.
Our panels were only 1-2m from the water cylinder with the pump sitting between them. We didn't have a heat dump.
When we went away for the first summer holidays, the panels got to setback temp (around 220 deg I think) and although the fluid wasn't circulating, the heat travelled down the pipe by conduction and burnt out the pump according to our installer.
He then put in an extra 10m of piping to prevent this happening in the future. It hasn't and there hasn't been a noticeable degradation in performance.
So you'd definitely be ok with 10m. Can't say for 20m.
It is rumoured that Darth will make a cameo appearance

There has been no degradation in performance because adding 10m of pipe is not going to reduce the heat of the fluid! If the system let's go the water turns to steam and travels all the way to your pump and expansion vessel. You are risking another disaster without a proper bypass. However the plumber will have to pay I guess.:rolleyes:

dr.fuzzenstein

freddyuk wrote: »

You could have East/West installation? Perfectly acceptable method.
20 metres is no problem at all.

I know what you mean, 10 tubes facing east, 10 tubes facing west. I am a bit unhappy with that one, the gable is facing sout-west by a few degrees, that means the east facing side is facing east-north and that collector would get very little direct sun, or only at a very bad angle.
I could do only west facing, since that is closer to south, but I would still be unhappy about it.
On the plus side, on the gable end (almost south facing, maybe a tad south-east) it would be out of sight along with all the internet antennas and leave the rest of the house visually uncluttered.
But I don't have an attic, so where will I put the damn pipe?!
Might have to consider West (well, South West) facing...
This may just work, since I need the solar more in the summer, because then the pellet burner is off and the solid fuel stove doesn't heat the water.

dr.fuzzenstein

freddyuk wrote: »

There has been no degradation in performance because adding 10m of pipe is not going to reduce the heat of the fluid! If the system let's go the water turns to steam and travels all the way to your pump and expansion vessel. You are risking another disaster without a proper bypass. However the plumber will have to pay I guess.:rolleyes:

Would this indicate the need for a heat dump into the central heating radiator system?

freddyuk

dr.fuzzenstein wrote: »

I know what you mean, 10 tubes facing east, 10 tubes facing west. I am a bit unhappy with that one, the gable is facing sout-west by a few degrees, that means the east facing side is facing east-north and that collector would get very little direct sun, or only at a very bad angle.
I could do only west facing, since that is closer to south, but I would still be unhappy about it.
On the plus side, on the gable end (almost south facing, maybe a tad south-east) it would be out of sight along with all the internet antennas and leave the rest of the house visually uncluttered.
But I don't have an attic, so where will I put the damn pipe?!
Might have to consider West (well, South West) facing...
This may just work, since I need the solar more in the summer, because then the pellet burner is off and the solid fuel stove doesn't heat the water.

Under the eaves back to where the cylinder is? Go in through the wall and box in if required to hide it?? Not sure of your set up so can't suggest more.