Solar Panel (s)

[Agile]

In spite of the hype that causes Paul and Drivel to both be taken in. I like the unit but they should be selling it as an add on the a NON-condensing boiler to convert it to a condensing unit in DHW.

The i/c water at 10°C can extract a lot of heat from the flue gases at 40-50°C and it would perhaps extract an extra 10-15% efficiency from the flue gases of a non-condensing boiler in DHW model.

Tony

 

[Nixt]

On the OP's original question. If 'payback' is an overriding issue then much of what's already been said would apply. However if you are pleased to invest in a value for money heating system which utilises otherwise wasted energy then all the renewables make sense. As all equipment in your home, apart from the building itself, is guaranteed to be worthless after a few years use then 'payback' should only apply if you intend to rip out a perfectly good efficient fossil fuel-fired system to replace it with alternatives.

Personally I prefer flat solar collectors to evacuated tube as they are more robust, require less maintenance and are unlikely to be damaged after installation.

 

[Agile]

Personally I prefer flat solar collectors to evacuated tube as they are more robust, require less maintenance and are unlikely to be damaged after installation.

I dont see why you should come to that conclusion. The tubes are lighter to install and they all say that they will not be damaged by hail stones.

The maintenence to tubes should be no more than flat panels and should the odd tube fail then it can easily be replaced from a ladder in most cases.

I want to fit solar to my house but I have a problem because I am next to a school and throwing stones is a common problem which rather rules out tubes and glass fronted panels.

Tony

 

[Nixt]

The tubes are lighter to install and they all say that they will not be damaged by hail stones.

Thats the problem they seem very fragile to me and I forgot to add look dog ugly. However I did pefix with the words 'personally I prefer' which is how I've reached my conclusion.

 

[gas4you]

If you had seen the last 2 Viessman flat panel installations that I happened to come across you would not say that. All panels on both installations cracked to bits after about 3-4 months when enquiring with the householder. Viessmann in disput with customers and won't honour any warranty. Luckily for one, he hasn't paid for them yet

 

[Agile]

The Viessmann flat panels have what seems to be plain glass on the fronts.

The demo cut off one at their HQ was cracked just like any plain glass.

Another make ( forgot which ) have a demo video with a couple of installers walking on the "glass" which I presume is toughened.

There are a lot of questionable aspects to solar installations. I dont think anybody has got it all quite right yet.

Tony

 

[micky p]

i have a pair of Viessmann flat panels on my dads house. Been in 3 years and no problems yet. everytime i service boiler i go up on roof and give them a quick rinse to clean any dirt that might be on them. Although Viessmann claim they do not require cleaning.
Think the Worcester panels are the ones where it shows a guy jumping on them. I have seen the cut out of the flat panel from viessmann and the glass looks very tough.
I also installed 90 tubes on a roof in Salford manchester and i was a bit scared of breaking one of them when installing, but to be honest i think you would have to throw a brick at one to break one.
Also if a tubes "goes down" as people like to put it, You will hardly tell the difference. The only things that could go wrong really, is if they will lose the vacum and drop back to the same efficiency as the flat panels.
Tubes are ideal for installs where you are a great heights or small areas, and if you have a low roof like a bungalow then flat panels are your one as they are a tad cheaper.

 

[Agile]

everytime i service boiler i go up on roof and give them a quick rinse to clean any dirt that might be on them. Although Viessmann claim they do not require cleaning.

You should get the window cleaner to do that!

Think the Worcester panels are the ones where it shows a guy jumping on them.

They look tough in the video!

I have seen the cut out of the flat panel from viessmann and the glass looks very tough.

Its well cracked now!

 

[micky p]

everytime i service boiler i go up on roof and give them a quick rinse to clean any dirt that might be on them. Although Viessmann claim they do not require cleaning.

You should get the window cleaner to do that!

Think the Worcester panels are the ones where it shows a guy jumping on them.

They look tough in the video!

I have seen the cut out of the flat panel from viessmann and the glass looks very tough.

Its well cracked now!

i very much doubt my window cleaner would climb on my roof haha.

 

[Agile]

i very much doubt my window cleaner would climb on my roof haha.

Many of them have telescopic poles now that would enable them to do it from the gutter position.

One I met in Reading had poles up to 30' long so that small office buildings could be cleaned from ground level. That enables him to employ some non climbing cleaners.

An interesting feature is that they have to use deionised water so that it does not leabe any lime scum on the windows. He had a 600 litre tank in his garage!

Tony

 

[micky p]

i very much doubt my window cleaner would climb on my roof haha.

Many of them have telescopic poles now that would enable them to do it from the gutter position.

One I met in Reading had poles up to 30' long so that small office buildings could be cleaned from ground level. That enables him to employ some non climbing cleaners.

An interesting feature is that they have to use deionised water so that it does not leabe any lime scum on the windows. He had a 600 litre tank in his garage!

Yeah i know a guy who i do work for who has one of these high level washers set up in his van. Thing is It is only 10 feet up a ladder and im there.
Worth bearing in mind i suppose.
Tony

 

[Balenza]

Gasguru wrote

A fully condensing Band A boiler will drop that down to say 40 or 50 Centigrade improving efficiency by 10 - 15%.

In DHW ?. A few on here believe condensing won't happen at all due to the plate delivering a high return temp to the main heat exchanger.

The gas saver will drop the flue gas down to 10 Centigrade at best. The extra efficiency will only be a few %.

Can you really be certain the extra efficiency is only a few percent considering your figures relating to flue temp are sceptical to say the least ?.

 

[kevindgas]

interesting debate !

all i can add is the facts of my own system

i have a 30 tube Apricus evacuated tube panel connected to my 210 litre OSO solarcyl

i have hot water everyday from Feb to Oct - Unless there has been 3 cloudy/wet days in a row
In the winter my clyinder gets up to about 30 - 35 by mid afternoon
so i save on gas all year round
i have my boiler set to come on at 6pm over the winter to finish off the heating of the cylinder and just use the 1 hour override in the summer if i need to boost the temperature

avoid the tubes like Vaillant's (now withdrawn) where the fluid runs down the tubes and back up as opposed to across the manifold only like the Apricus (i have 1 tube cracked at the moment and it still works perfectly ok)

 

[Agile]

Can you explain the heat transfer mechanism which your tubes use? And who supplies them?

How many people use the hot water from your 210 li cylinder?

Tony

 

[kevindgas]

the tubes use heat bulbs to transfer the heat from the dry solar tubes to the wet manifold. a simple design the seems to work fairly well and no fluid runs in the tubes so it works even with a broken tube so long as the heat rod is undamaged

2 of us use the water to shower etc (we have a 8" rain water shower) and we get a good shower of about 5 mins each with an average temp loss of 10 / 20 degrees upper/lower in the cylinder