Which Solar Panel?

bouli73

HI
would be grateful for advice please.
We are in the middle of a house build at the moment. Included in the contract price was supply & fit of 30 tubular solar panels with 300ltr triple coil solar tank.
The contractor's plumber has been in contact with me recently. He is advising strongly that we go for the Kingspan solar panels at an extra cost of €700. He advises that there was a lot of problems with solar panels last summer during the heat wave, anti freeze having to be drained etc as these models did not have a facility to shut down once water temp reach 65c. He advises that Kingspan uniquely has such a feature and that we should go with it. He acknowledged that other models have a "heat dump" or means of releasing water but he did not think this was the way to go.

I should say he is very highly regarded and I don't think he is pulling a fast one but would just be grateful for the views of others on this. Hopefully I have explained it well enough but please excuse if I haven't, not a plumber !!

PeteFalk78

I may be doing the same except I'm doing a retrofit. Caught in the same dilemna. Go for the cheaper Chinese panels for 3.5k or Kingspan at 5k.

To me paying only €700 to upgrade to Kingspan seems like a very good price.

I'll certainly keep an eye on this thread for more feedback.

freddyuk

The Kingspan tubes have an inbuilt bypass system which may or may not actually operate as it is spring loaded. Under the warranty conditions if the panel is subject to excessive stagnation conditions the warranty is invalid!

Quote:
G. The Goods having been subjected to neither “prolonged stagnation conditions” nor exhibiting signs of “extreme
temperature exposure”

So if the safety system fails to operate they run away?
Cute.

You also need to have the system annually serviced by a qualified installer to maintain the warranty so factor that into the cost.
Or you can have a simple automatic radiator by pass which in the event of a problem can be manually activated if required. All decent controllers have this system inbuilt to the software.

richieburke01

freddyuk wrote: »

The Kingspan tubes have an inbuilt bypass system which may or may not actually operate as it is spring loaded. Under the warranty conditions if the panel is subject to excessive stagnation conditions the warranty is invalid!

Quote:
G. The Goods having been subjected to neither “prolonged stagnation conditions” nor exhibiting signs of “extreme
temperature exposure”

So if the safety system fails to operate they run away?
Cute.

You also need to have the system annually serviced by a qualified installer to maintain the warranty so factor that into the cost.
Or you can have a simple automatic radiator by pass which in the event of a problem can be manually activated if required. All decent controllers have this system inbuilt to the software.

All true but there is a cost to put in bypass
Radiator,3 port valve,different controller the standard controller usually don't do this function (depends on type) and of course all the extra fittings and pipe work
I'm a Kingspan installer you won't go wrong with this product
A short story
A 2 years old Kingspan system it gave trouble faulty controller
Rang Kingspan and within 2 hours they contacted house owner to organise warranty call to sort this out

freddyuk

You won't go wrong with a cheaper Chinese branded panel with a chinese controller that has By pass circuit as well as many other functions as standard options. No fancy valves and springs to go wrong as no moving parts.
The controller is not the issue here as we are concerned about heat related issues. Most problems are caused by incorrect design/ installation or lack of bypass.
Cost of bypass valve (fitted in place of elbow joint) €90 + Radiator €40 + copper pipe €20 + two radiator compression fittings €8 + T joint to return flow. I know pipe benders are unheard of but it saves on joints and gives a better flow if used. So if done at time of installation it is not a big cost at all.
If a Chinese tube fails after so many years then just replace it for about €20. They fail no more often than Kingspan tubes I would say.
I think Kingspan make some good kit but if the price puts buyers of having solar heating I think the cheaper options should be offered and supported as they are just as good and maybe better. Heat output will be no different.

richieburke01

freddyuk wrote: »

You won't go wrong with a cheaper Chinese branded panel with a chinese controller that has By pass circuit as well as many other functions as standard options. No fancy valves and springs to go wrong as no moving parts.
The controller is not the issue here as we are concerned about heat related issues. Most problems are caused by incorrect design/ installation or lack of bypass.
Cost of bypass valve (fitted in place of elbow joint) €90 + Radiator €40 + copper pipe €20 + two radiator compression fittings €8 + T joint to return flow. I know pipe benders are unheard of but it saves on joints and gives a better flow if used. So if done at time of installation it is not a big cost at all.
If a Chinese tube fails after so many years then just replace it for about €20. They fail no more often than Kingspan tubes I would say.
I think Kingspan make some good kit but if the price puts buyers of having solar heating I think the cheaper options should be offered and supported as they are just as good and maybe better. Heat output will be no different.

I agreed but what about the cheaper kits out there that won't heat the cylinder above 45 degrees on the hotter day of the year
It's hard for customers to tell the good kits from bad one
Germany gave a great system
They have classes
Class1
Class2
Class3
And so on
Then you have these kits with efficiencies but a high grade cylinder is used as part of the test
Then they are sold here with a low grade cylinder and all the efficiencies go out the window
I tried to service one of these systems the other day
Customer tells me he is losing 23 degrees of heat from his cylinder overnight and all pipes are insulated done by himself (class o)solar and domestic
Kingspan are expensive but they work,good customer service and back up
5-20 warranty
All what the customer looks for
I saw to many horror stories and it's always the same out come
That's what the installer recommended

freddyuk

Exactly - bad design and incorrect installation. Without a non return valve etc. the system will empty itself. This is not the fault of the collector but bad installation by a bad installer. :mad:

richieburke01

To true freddy

PeteFalk78

freddyuk wrote: »

Exactly - bad design and incorrect installation. Without a non return valve etc. the system will empty itself. This is not the fault of the collector but bad installation by a bad installer. :mad:

Thanks Freddy and Richie for your advice.
Freddy could you elaborate on the non return valve? Do you mean a heat dump to a radiator? Is it a manual bypass or automatic?

quentingargan

To my mind, in any system it is better to have a heat dump. The tubes with built-in valves may stop the water from boiling, but they reach extraordinary internal temperatures. If you are relying on this as your only protection, you are constrained from fitting enough tubes to completely heat your water on the fringes of the season. I prefer to see a larger number of tubes to ensure sufficient production across spring to autumn, and a heat dump. The controller will have a relay to operate the dump load valve when the cylinder gets to temperature. Your system may still stagnate in a power cut, but there are too may systems out there that stagnate every sunny day, causing the water in the panel to turn to steam, degrading the glycol in the process.

John T Carroll

richieburke01 wrote: »

I agreed but what about the cheaper kits out there that won't heat the cylinder above 45 degrees on the hotter day of the year
It's hard for customers to tell the good kits from bad one
Germany gave a great system
They have classes
Class1
Class2
Class3
And so on
Then you have these kits with efficiencies but a high grade cylinder is used as part of the test
Then they are sold here with a low grade cylinder and all the efficiencies go out the window
I tried to service one of these systems the other day
Customer tells me he is losing 23 degrees of heat from his cylinder overnight and all pipes are insulated done by himself (class o)solar and domestic
Kingspan are expensive but they work,good customer service and back up
5-20 warranty
All what the customer looks for
I saw to many horror stories and it's always the same out come
That's what the installer recommended

I know I have posted this comment previously but I would still like to know why the "Flat Plate" predominates (or at least did) in Austria and Germany who would have weather patterns, broadly speaking, similar to us, The E.Tube is, quite rightly, in my opinion, very popular both here and in the UK.

""Evac. Tube % of 2010 European Market is as follows: (I just sampled 4 countries.)
Austria 4.2%
Germany 10%
Ireland 42%
UK 28%""

championc

I have the kingspan panel and my store has held water at 80 deg. The one thing I notice about it is that the Kingspan system delivers pretty much the same results right across the day when hit by the sun, as opposed to going great guns when the sun is directly overhead.

A tripple coils is the way to go. I assume you plan to link one to a boiler for topping up but then use the other two off the solar, configuring the system for top loading.

Finally, make sure the controller you get has a data logger. The TR0603mc takes an SDCard. It gives great comfort when you can actually see that the system is actually doing what you hoped and expected it to do.

I have tweaked my system over and over, after setup of the top loading. I was able to analyse all changes I made by reviewing data minute by minute.

richieburke01

championc wrote: »

I have the kingspan panel and my store has held water at 80 deg. The one thing I notice about it is that the Kingspan system delivers pretty much the same results right across the day when hit by the sun, as opposed to going great guns when the sun is directly overhead.

A tripple coils is the way to go. I assume you plan to link one to a boiler for topping up but then use the other two off the solar, configuring the system for top loading.

Finally, make sure the controller you get has a data logger. The TR0603mc takes an SDCard. It gives great comfort when you can actually see that the system is actually doing what you hoped and expected it to do.

I have tweaked my system over and over, after setup of the top loading. I was able to analyse all changes I made by reviewing data minute by minute.

Yeah I've done something like that but using that 3 coil to strip heat out at 80 and stop at 60 into the heating system

championc

richieburke01 wrote: »

Yeah I've done something like that but using that 3 coil to strip heat out at 80 and stop at 60 into the heating system

I was considering this but TBH, I'll only get 80+ during the summer - the one time when you most definitely will not need your heating to be turned on.

So I didn't think it was worth the added complexity or additional pipework.

John T Carroll

championc wrote: »

I was considering this but TBH, I'll only get 80+ during the summer - the one time when you most definitely will not need your heating to be turned on.

So I didn't think it was worth the added complexity or additional pipework.

That's interesting. If K.Span,s loss numbers of (0.727/0.85/0.0093) are to be believed, then, theoretically, at least, even with an ambient of 15C and relatively moderate solar radiation of 500 watts/M2 then the collector should reach 172C before reaching stagnation, I was under the impression that if the cylinder was up to temperature on ANY sunny day that the tubes would reach very high temperatures of up to 250C, assuming no water draw off.

championc

John T Carroll wrote: »

That's interesting. If K.Span,s loss numbers of (0.727/0.85/0.0093) are to be believed, then, theoretically, at least, even with an ambient of 15C and relatively moderate solar radiation of 500 watts/M2 then the collector should reach 172C before reaching stagnation, I was under the impression that if the cylinder was up to temperature on ANY sunny day that the tubes would reach very high temperatures of up to 250C, assuming no water draw off.

I think my cutoff is set to 80 or 85. Last summer, my tubes went up to 156 after shut off