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Solar Thermal Hot Water System
 Started by  k.kivlehqn
 11 Jun 2010, 3:39 PM


We have had a cold call from a company EcoHome Services Ltd who have been along to quote for a system. We have a very old boiler and ancient system of radiators c 1920? Three storey 8 bed house. Old Water cylinder with no temp control. Gravity feed. Gas bills are nightmare. We looked at PV some years ago but couldn't afford. This co. quote to fit 18 tube Ritter panel on garage roof which is on side of building and almost on top of boiler room as roof is difficult to site with dormer windows. Twin Coil solar cylinder 250 ltr , solar heating controls. Boiler - 1 Viessmann system boiler 35kw controls & programmer with weather compensation system and Y-kit system I think this as to stop bleed-back of heat into rads when water only needed. All work completed for 9,200. We are 2 adults and 3 teenagers. Co. did not think the heating system lent itself to solar power so just looking at water. They made much of saying that they were not the cheapest but they use proper soldering stuff to withstand extreme heat generated by system and proper pumps not just central heating pumps. 10 yr guarantee on Ritter panel, 25 yrs on cylinder, 3 yrs on labour & materials.
 
a) does anyone have knowledge of this co?
b) does above sound good advice?
c) are we being ripped off
d) could a competent plumber do as good a job.
 
We are complete novices at DIY so please be gentle with us.

tony
too expensive
 
how about spending on draught proofing and insulation first
 
then solar hot water including cylinder should be about 3.5 and new boiler if you still need a boiler 3.5 too
 
a local plumber should be able to get close to my price for you.
 
You can use compression fittings on the solar to save the need for brazed fittings -- dont use solder with ET's as it can melt!
 
NiallMac
Tony is right about the boiler, 3,500 tops to install. This should include a powerflush if you shop around.
 
The solar thermal is slightly more difficult to gauge, but my feeling is that it is expensive as the installation does seem easy, being on a garage roff.
 
What confuses matters is the other workyou are haveing done.
 
I would shop around a bit more, but remember that the solar i8nstaller needs to be MCS accreddited or you won't be elligible for the Renewable Heating Incentive, which might be worth 300-400 p.a.
 
Where are you based?
 
heinbloed
The OP neither gave a Wattage of his planned Viesmann boiler nor a model nor a type of fuel.
So I wonder how a price comparrisson can be made, an answer be given to his/her question ?....
 
A gas fueled condensing boiler with a fuel efficiency of over 90% is available in most DIY markets for much less than 1,000.-....
So I wonder how the previous posters get to their price estimations?
The storage tank for the ST system should come with the ST collectors.
The OP planned a "Ritter panel" - but doesn't say how high the harvest would be. The harvest and it's usage would determine the sizing, the type of the thermal storage tank.....
 
My advise to the OP: get a professional energy adviser, someone who isn't interested in selling a product but a service with a full guarantee. Internet chatrooms are no guaranteed advise, just opinions by people with or without vested interests, with or very likely without an overview of the situation. See the 'phantastic' answers above....
 
Get the energy demand calculated and the supply via a variety of systems guaranteed. Invest two or three hundred pounds in professional work, in proper advise.
Then you can still employ the cheapest plumber who has to work acording to the drawings in the plans. With the materials stated in the plans.
 
All other aproaches are like the fish who asks for the most tasty bait.
 
PS
Yes, you are on the list of today's catch.

 
k.kivlehqn
Many thanks for the advice. Am speaking to other companies and with the company above in light of your info and so far they have been open and helpful.
Couple of of questions
We need 5 showers weekdays by 7.30am. claim is that ST system requires only about 1 hour to heat 200 ltr tank. Is this achievable? As this is about our only hot water requirement during day it's quite crucial on making this cost effective.
Claim also that only 3-4 degrees heat lost overnight on good cylinder although ecohomes were perhaps more accurate with 1 degree per hour. Is this likely to produce anything in winter where nights are much longer?
It seems an awful waste for daytime heat not to be useful - are there any uses we could put it to other than heating?
 
heinbloed
@ K. Kivlehqn:
 
1. question first:
 
Yes. But not with a system you have mentioned above.
Standard quality collectors would have to be exposed to full sunshine (in the morning?!) and be plentyfull in terms of m2 to get you to this harvest.
 
2. question :
 
The second calculation seems to be nearer to reality. But it can be much worse. Real plumbers are demanded for the job.
It's a question of surface/volume ratio, insulation and thermosyphoning. Thermosyphoning is a common problem with DIY installations, DIY stands for the cowboys in the trade as well.
 
There are now vacuum (flat) collectors available. These have an efficiency rating of over 90%. Meaning they turn 90 % of the sun's light energy into usefull energy.
But they come for a price, around 400.-/m2. These will indeed cover Winter demand, even on cloudy days when facing North. For all other installations a back-up is necessary.No matter how good they're scoring on the Estif list(solar keymark).
 
For these new high efficiency collectors see
 
 
http://www.srbenergy.com/pages/principales-caracteristicas
 
The last question( "It seems an awful waste for daytime heat not to be useful - are there any uses we could put it to other than heating?") I do not understand. Sorry.
 
Get a heating engineer into the project, don't rely on salesmen talk.
 
Good luck!
 
 

 
thermalsolar
Hi I run thermal Solar Solutions in Doncaster and have some information for you about your quote. In your original post you said that the boiler size is around 35kw. I can assure you that boiler for the size of your house is far to small . From what you are saying you would need some thing that produces around 47 KW. there are a few good reliable manufacturers such as Keeston and Worcester that provide that amount of heat . Originally designed for small commercial installs as I believe your house is. The installation of a y plan in your house is an incorrect type of heating system. Y plans can be installed on anything up to and including 80.000 BTU's. Your system and the fact that it is a solar enquiry must have a S plan system. this way you get the correct amount of heat delivery to your heating system.
 
With the boiler being a larger boiler it will achieve its condensate temperature and will then be efficient.
 
If you have a look at Kingspan on google you can type and size your hot water requirements from their online questionnaire. it will then give you the choices of collector type and heat yield requirement for you house.
 
Getting involved with thermal calculations at the consumer level is mind blowing, Kingspan have made that process allot easier to decifer by the simplifying its installation questions. one of your posts was correct in trying to insulate your house at the same time and try to get rid of the drafts. Lagging your pipework is also the essential for solar hot water cylinders. Heat that is generated by the solar system can reach very high temperatures and can burn on contact.
 
I have quoted large victorian houses and have come out at a max cost of 8,999.00 for the system above from kingspan. if you need any help have a look and give me a call
 
regards
 
nigel
 
heinbloed
Hi thermalsolar!
 
Have you used/installed the kingspan heat pipe tubes? Single glazed evacuated tubes with the heat pipe made from stainless steel?
Any problems with them? They are not manufactured anymore so I wonder if they're still sold.
Thanks!
 
technicalm
it's quite frankly nonsense to say, based on the limited information provided that 35kW is insufficient for the house.
 
Viessmann are uber quality boilers and come at a price.
 
Thermal stores aint cheap and neither is ritter solar.
 
And, something we seem to be forgetting, neither is the expertise to do it properly.
 
It is not a job for a plumber - it's a project for a skilled, qualified heating engineer.
 
Hope it goes well.
 

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