The Renewable Energy Hub Forum

Renewable Energy => Solar Thermal & Solar Hot Water Systems => Topic started by: Cas on December 05, 2018, 01:49:56 PM

Title: Can anyone recommend a good solar thermal system?
Post by: Cas on December 05, 2018, 01:49:56 PM
Hi all,

Around 8 or nine years ago I got a Thermomax water heating system installed.  It was not cheap, but at that time the tubes came with a 20 year warranty, so I thought at least my investment was pretty safe.  Some chance!  Thermomax went bankrupt, and were taken over by Kingspan, who naturally would not stand by the guarantees made by the old version of the company.

Now the system was unlikely ever to have paid for itself even before this, since the panels were extremely prone to leaks.  This led to regular visits from the supplier, the labour part of which I had to pay.  This alone would have amounted to far more than the cost savings that the panels ever produced, so when the manifold eventually developed a large leak that would have required its replacement, I ended up simply switching it off.  It has been a pure roof decoration for about 2 years now.  There is no way that I would ever replace this system with something similar; they are simply far too unreliable and far too expensive, especially when that unreliability is taken into account.  This is a pity, because when it did work, it produced a lot of very hot water.

I have recently been looking at air source alternatives, and have found 3 different systems available.  A local fitter uses the Portuguese made Energie systems, but a quick internet search shows that these may be as unreliable and poorly supported as my original Thermomax system.   I also contacted Magic Box, but yet another supplier hinted that these too are far from reliable.  Needless to say, he was pushing his own  (Bunsen) system.  To make any of these heating systems pay for themselves in a reasonable timeframe they need to be both ultra reliable and efficient.  In half decent weather, the COP (coefficient of performance) for them seems OK, but no where near as good as the touted figures from the sales reps (in fact they unanimously say that COP figures mean nothing but cannot replace it with any meaningful measure of their systems performance.  In cold weather, it seems that it would be more cost effective to run an immersion heater!  That last COP  figure is pretty damning.  Quotes for installation range from around 2500 to 3500.  I really do not want to pay this for something that will be yet another roof decoration in a few years!

So here are my queries:

1)  Does anyone out there have any direct experience, good or bad, of any of these systems over a long period (say, 5 years or more)?
2)  What should such a system cost to install and to run (remember that I already have a good solar water tank)?
3)  Are there any alternatives that I may not have considered yet?
4)  How much maintenance/ replacement parts  are they likely to require?

Thanks in advance,


Title: Re: Can anyone recommend a good solar thermal system?
Post by: Cas on January 17, 2019, 10:51:18 AM
Surely someone out there must have some experience of these systems?  Your advice would be greatly appreciated.