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dougal



Joined: 15 Jan 2005
Posts: 7184
Location: South Kent
PostPosted: Wed Nov 16, 05 12:19 pm    Post subject:  Reply with quote    

Treacodactyl wrote:
...Gas may be a good option now but what about the price in 5 years, could it double?

ALL energy prices are likely to rise.
And that will 'knock-on' into prices of any manufactured or transported item, according to its 'energy content'.
Most UK gas is used for industry and electricity generation, IIRC.

Electricity is likely to remain far the most expensive kwh for kwh, although the relationship between electricity/oil/gas/coal/wood will adjust with market conditions - based on demand, after all, and hence somewhat self-adjusting.

But it certainly makes sense to look to allowing oneself the potential for some diversity...

tawny owl



Joined: 29 Apr 2005
Posts: 563
Location: Hampshire
PostPosted: Wed Nov 16, 05 12:42 pm    Post subject: Reply with quote    

Jonnyboy wrote:
Easy, your thermostat would be linked up to the pump with an override, so it won't start to heat the radiators until the tank is good and hot


Or you could just have an immersion heater that would heat just the top bit of the tank - enough for usual washing needs.

Andy B



Joined: 12 Jan 2005
Posts: 3920
Location: Brum
PostPosted: Wed Nov 16, 05 1:25 pm    Post subject: Reply with quote    

sean wrote:
Insulation first, including replacing windows if necessary. I'd give serious thought to a woodburner for heating and water. I think there was a thread here about grants being available for this.
Jamsam, a properly set up and used woodburner should be generating almost no smoke anyway. Clearview stoves are licensed to burn wood even in Smoke free zones.


If the windows are sound and original please dont replace, what you can do is get them double glazed, they replace the window bit and replace the weights and it costs about 500.00 per window.
And clearview stoves are very good !

giraffe



Joined: 07 Oct 2005
Posts: 272
Location: Nottingham
PostPosted: Wed Nov 16, 05 1:40 pm    Post subject: Reply with quote    

don't worry Andy we're not ripping out any original features - (unlike the previous owners )double glazing was what I meant.

Jonnyboy



Joined: 29 Oct 2004
Posts: 23924
Location: under some rain.
PostPosted: Wed Nov 16, 05 1:44 pm    Post subject: Reply with quote    

sean wrote:
Jamsam, a properly set up and used woodburner should be generating almost no smoke anyway. Clearview stoves are licensed to burn wood even in Smoke free zones.


True, mine doesn't even shove out enough white smoke to shout habemus papus

dougal



Joined: 15 Jan 2005
Posts: 7184
Location: South Kent
PostPosted: Wed Nov 16, 05 2:52 pm    Post subject: Reply with quote    

Judith wrote:
dougal wrote:
Note that solar and wood burner could also contribute, as and when, to the same thermal store...


In our experience, the thermal store / solar water heating combo hasn't been a happy one. Our store was designed to keep the water at a constant 60 C temperature at all times of the day and night. As a result, the boiler would cut in constantly before the solar panels had a chance to do their stuff. This 60 value was fixed, so the only way to get any value from the solar panels was to turn the boiler off altogether - which is not a satisfactory situation. After around a year of arguing with the thermal store supplier, they finally produced a new chip for us - the minimum temperature in the store is now 50. We would have preferred 40, but they wouldn't come down that low.


Judith - there seems to be a communication disconnect or a mistaken design here.

Ordinarily, the solar coil should be in the bottom of the tank, where it can heat the coldest, just arrived water.
The boiler would be controlled by the temperature of water near the top of the tank. Thus the boiler ensures that there is always water available at the appropriate temperature, while the solar system reduces the work that the boiler has to do.
Consolar diagram here.
Note that the boiler *cannot* heat the water at the bottom of the tank...
The basic idea is that the solar tries to heat the whole tankful, and the boiler just "tops up" the heat needed.
It sounds like your system has that back-to-front.


I can imagine that things would be more difficult if a "direct" thermal store were used (where the contents of the tank circulate through the boiler. But AFAIK that would be plain wrong to combine such a design with a solar coil in that store. (One might combine that type of store with a solar pre-heat in a second tank...)

The main reason that I would recommend evacuated tube solar collectors is that they will reach a useful temperature for more of the year. Flat plate collectors may struggle to deliver any heat for 4 or months of the year - but flat plate has traditionally had a big price advantage...

I'm a bit mystified as to what your system might actually be, not least because it would be normal to provide an adjustable thermostat rather than a "chip". There are lots of differences between the things that different people call "thermal stores"...
And it would be normal to have the boiler on a timeclock. There is no point whatsoever in having the boiler 'cycling' at 3am, rather than (if required) having a decent run at 7am... And it certainly should not be needed to have the boiler switched on 24/365.

I think you perhaps ought to call in an independent heating engineer to look at exactly what your system is, and how its being used.

Its quite mainstream, and effective, to combine solar with a boiler by the use of an appropriate thermal store.
And its the normal way in which multiple heat sources would be integrated.

EDIT: long link text tidied up.

Last edited by dougal on Wed Nov 16, 05 3:59 pm; edited 1 time in total

judith



Joined: 16 Dec 2004
Posts: 22789
Location: Montgomeryshire
PostPosted: Wed Nov 16, 05 3:02 pm    Post subject: Reply with quote    

dougal wrote:
I'm a bit mystified as to what your system might actually be, not least because it would be normal to provide an adjustable thermostat rather than a "chip". There are lots of differences between the things that different people call "thermal stores"...


We have a Gledhill Boilermate with the Solarpod attachment. From page 5 of the user manual:
"Why is the boiler constantly switched to the "ON" position?
The system operates most efficiently if the boiler is always left on, with the boiler thermostat always at its maximum setting - even in summer. This is because the intelligent electronics within the Thermal Store control the system temperature automatically based on demand. Your system should, generally, be left 'on' at all times."

Quote:
And it would be normal to have the boiler on a timeclock. There is no point whatsoever in having the boiler 'cycling' at 3am, rather than (if required) having a decent run at 7am... And it certainly should not be needed to have the boiler switched on 24/365.


Edited to say that it took almost 12 months for Gledhill to admit that this wasn't a sensible situation, and make the modifications we requested! I would be happy to send you copies of our correspondence if you are interested.

Last edited by judith on Wed Nov 16, 05 3:11 pm; edited 1 time in total

Northern_Lad



Joined: 13 Dec 2004
Posts: 14210
Location: Somewhere
PostPosted: Wed Nov 16, 05 3:07 pm    Post subject: Reply with quote    

dougal wrote:
Note that the boiler *cannot* heat the water at the bottom of the tank...


Yes it can.
If both elements are in the same tank, and the tank is well insulated then the hot water at the top will transfer some heat to the cold water underneath it. Granted, it's a slower process than having the element at the bottom and utilising convection currents, but it will still happen.

dougal



Joined: 15 Jan 2005
Posts: 7184
Location: South Kent
PostPosted: Wed Nov 16, 05 3:27 pm    Post subject: Reply with quote    

Northern_Lad wrote:
dougal wrote:
Note that the boiler *cannot* heat the water at the bottom of the tank...

Yes it can.
If both elements are in the same tank, and the tank is well insulated then the hot water at the top will transfer some heat ...


I'm sorry you didn't follow what I was trying to say.

If you look at the consolar diagram you will see that the bottom of the boiler coil (return to boiler) is well above the top of the solar coil.

Obviously there will be *some* conductive heating downward to the lower water...

However, the point is that the system be designed to allow the solar coil to be surrounded by the *coldest* possible water, in order to transfer the *maximum* useful heat from the solar collector.

dougal



Joined: 15 Jan 2005
Posts: 7184
Location: South Kent
PostPosted: Wed Nov 16, 05 3:53 pm    Post subject: Reply with quote    

Judith wrote:
dougal wrote:
I'm a bit mystified as to what your system might actually be, not least because it would be normal to provide an adjustable thermostat rather than a "chip". There are lots of differences between the things that different people call "thermal stores"...


We have a Gledhill Boilermate with the Solarpod attachment.


Right. I've never heard of the Solarpod, and though there is a mention of it on Gledhill's website, there is no info about it at all.

Gledhill are well established as a high-quality tank manufacturer, though they have not been (themselves) particularly involved with solar systems. (They supply tanks to many systems integrators though).

The "Boilermate" is a basic direct thermal store.
This is a diagram of the Boilermate:


I can imagine that the "solarpod" might well be a secondary "pre-heat" tank as I mentioned in my previous post, above. Essentially, I'd expect it to pre-heat the cold water inlet to the Boilermate in the above diagram. Thus the solar only contributes to the hot water.

The arrangement isn't daft, and should work - but it is very far from an ideal design.
You *shouldn't try to reduce the thermal store temperature.

When solar heated water "passes through" the store it will be "topped up" to the requested hot water temperature by heat from the store.
It will only take out the heat required to 'top it up'.
In summer this should be zero. Which means the boiler doesn't need to fire up to replace that heat.
The disadvantage is just that the store must be hot (boiler heated) to avoid cooling the solar-heated water! (Because the store is super-insulated, this shouldn't be a massive disadvantage).
In winter, its likely very close to the same as without the solarpod - but it should never be more than without it.

Gledhill do offer a "proper" solar-integrating thermal store, the "Torrent"
http://www.gasapplianceguide.co.uk/gledhill_torrent_solar.htm

There's a (big) diagram here
http://www.gasapplianceguide.co.uk/Dia%20large.jpg
where you will note the solar coil working in the *coolest* part of the tank.
And contributing to the *store* - not directly to the hot water. And thereby (potentially) allowing the boiler to be turned off for the summer...
I don't know if Gledhill offer the option, but a coil fron the woodburner could take the place of the immersion element in this diagram.

Treacodactyl
Downsizer Moderator


Joined: 28 Oct 2004
Posts: 25697
Location: Jumping on the bandwagon of opportunism
PostPosted: Fri Nov 18, 05 7:46 pm    Post subject: Reply with quote    

dougal wrote:
Treacodactyl wrote:
...Gas may be a good option now but what about the price in 5 years, could it double?

ALL energy prices are likely to rise.
And that will 'knock-on' into prices of any manufactured or transported item, according to its 'energy content'.
Most UK gas is used for industry and electricity generation, IIRC.

Electricity is likely to remain far the most expensive kwh for kwh, although the relationship between electricity/oil/gas/coal/wood will adjust with market conditions - based on demand, after all, and hence somewhat self-adjusting.

But it certainly makes sense to look to allowing oneself the potential for some diversity...


While it would seem logical for energy prices to balance in the short term they may not. I remember my mum having an oil fired boiler installed and a year or so afterwards oil prices rising much faster than gas and now I notice whole-sale gas prices have doubled in the last week.

As industry and power generators are not going to switch to wood fuels for a long, long time, and households are not going to suddenly replace their new gas boilers I would think wood and wood products as fuels to get cheaper. And, of course, you can buy a piece of woodland.

dougal



Joined: 15 Jan 2005
Posts: 7184
Location: South Kent
PostPosted: Fri Nov 18, 05 8:12 pm    Post subject: Reply with quote    

Yes, there are always going to be short term variations.
I gather that gas supplies are likely to be a bit tight for the next couple of winters. The problem is the speed of construction of transport infrastructure - pipelines from Russia and tanker terminals for gas from North Africa.
The reserves exist, its transport that's the bottleneck.

And when supply is constrained "spot" prices can rise alarmingly.
BUT I think most distribution companies are on very long term contracts, and so the volatility in the spot market ought to have much less effect than it might appear to...

Sensible thing is have some diversity of supply - and a source of wood is certainly one option. As previously noted, there are many strange influences on woodland prices...

gil
Downsizer Moderator


Joined: 08 Jun 2005
Posts: 18377

PostPosted: Sat Nov 19, 05 12:00 pm    Post subject: Reply with quote    

double glazing ? How about internal wooden window shutters ?
instead of, or as well as.
giraffe - do you still have originals in place ? could you renovate or install ?

Also, if you've got sash windows, you can get single glazed ones with brush-type draught excluders round the edges (which also stops them rattling). Apparently most of the heat lost through this kind of window is round the edge, not through the glass. Double glazing makes me think of condensation, and older houses not being able to breathe properly.

But I'm not an expert on this kind of thing, and my window shutters are way down the to-do list.

dpack



Joined: 02 Jul 2005
Posts: 34457
Location: yes
PostPosted: Sun Nov 27, 05 4:55 pm    Post subject: Reply with quote    

draughtoroofing, insulation and double glazing willpay for themselves in that order .then go for energy efficient equipment .

dougal



Joined: 15 Jan 2005
Posts: 7184
Location: South Kent
PostPosted: Sun Nov 27, 05 7:12 pm    Post subject: Reply with quote    

dpack wrote:
draughtoroofing, insulation and double glazing willpay for themselves in that order .then go for energy efficient equipment .

Yep, that's the standard advice - BUT - unless any (combustion) heaters are "room sealed" (drawing their own combustion air in through their own flue system) then you *must* have a good supply of fresh air (or risk Carbon Monoxide poisoning). And that air supply means draughts...

Hence upgrading the heating (an expensive item) may allow better draughtproofing (which is cheap!)
And an efficient boiler might reduce the fuel consumption by 20-30% compared to 'traditional' designs. And that % saving would apply to whatever consumption would be expected from the levels of insulation employed...

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