This time it's about Oil Boilers

[NT]

re solar with remote collection:

If you're not able to quantify cost and heat loss of a system or pipe run you'll need help from eg news:alt.solar.thermal. Theres no way you can design a solar system until you can quantify these things. Its not difficult.



"What I haven't yet seen is powered TRVs for each radiator, allowing different temperatures at different times for different rooms, controlled centrally or overidden locally,"

What I'm describing is simpler than that. It is simply an adjustable room thermostat controlling the TRV. Contro is achieved with a miniature LV heating element on the TRV.

This gives thermostatic temp control but no independant timing control. It means you can set the room temp dial to anything you like instantly, which is not really achievable with TRVs. It also means you have proper thermostatic control, which is a considerable improvement on TRVs, which are a lot less thermostatic than would be ideal.

The low cost of this approach makes it practical to make every room a separate subzone. It also gives a much better level of owner control than TRVs.



"But Legionella is something to be aware of for anything that systematically deals with water n the danger temperature range"

1. The storage type exchangers only store the water headed for the drain, so any bugs only have access to the drain.
2. The stored water is chilled by incoming cold mains water to below 20C
3. Bug killing shower/bath/sink/etc cleaners kill off bugs in storage. Bleach kills legionella.
4. Copper is biocidal, and these exchangers are usually copper.


NT

 

[NT]

"I'd like to clear up the boiler efficiency thing though.
Is this correct?"

Not really, no... try uk.d-i-y.


Showers are the ideal app for non-storage exchangers, the storage ones are effective for whole house use.

I dont have any figures for horizontal use, but if it were the only option I'd be tempted to try one or seek some info on exchange rates.


NT

 

[Aidan]

3. Bug killing shower/bath/sink/etc cleaners kill off bugs in storage. Bleach kills legionella.NT

It does, but the concentration used in the occasional dose of a cleaner is not effective disinfection.

4. Copper is biocidal, and these exchangers are usually copper.

Copper has some biocidal effects, but mainly in respct of the use of copper alloys on door furniture. In heating systems it will be often coated with a layer of scale or biofilm and not all the water will contact it. It is not an effective legionella control device. You must control it with the temperature regime, i.e., keep cold below 20degC, keep hot above 60 degC. Legionella and showers (atomization) is not a healthy mixture. It will kill you & yours.

 

[Flyfisher]

I may be missing something but I can't really see the point in storing lots of lukewarm water, regardless of the Legionella risk (although my view is that such a risk is not worth any DHW energy savings - there are limits!).

In our household, showers are the biggest consumers of DHW and recovered heat can be fed directly back into the cylinder, so there's no additional lukewarm water to store.

I don't know how much heat could be recovered from a cool wash cycle, but I doubt it's that much, so nothing much worth storing there.

All in all, I'm feeling fairly happy with just the shower heat exchanger.

 

[NT]

3. Bug killing shower/bath/sink/etc cleaners kill off bugs in storage. Bleach kills legionella.NT

It does, but the concentration used in the occasional dose of a cleaner is not effective disinfection.

yes, its just one of many things that keep bacterial populations down.

4. Copper is biocidal, and these exchangers are usually copper.

Copper has some biocidal effects, but mainly in respct of the use of copper alloys on door furniture.

Do you have a ref for this? AIUI its the copper rather than the metals its alloyed with.

In heating systems it will be often coated with a layer of scale or biofilm and not all the water will contact it. It is not an effective legionella control device. You must control it with the temperature regime, i.e., keep cold below 20degC, keep hot above 60 degC.

Its one option.
http://en.wikipedia.org/wiki/Legionella

Legionella and showers (atomization) is not a healthy mixture. It will kill you & yours.

Legionella-prone water is not being fed to the shower at any time. There is a double wall exchanger between the sometimes warm water and the feed to the shower or HW tank. The stored warm water only ever goes one place, the drain.


NT

 

[AMc]

RE Oil purchasing
They don't use BoilerJuice AFAIK - they collate orders from residents then call around the local suppliers for the best price on the agreed day of delivery.
My understanding is the oil price varies from supplier to supplier, that the more you buy the lower the price and like almost anything else suppliers may drop a few pence per litre to meet their own supply and demand requirements.
I really must check it out in more detail as it looks like our last delivery won't quite outlast the winter heating season

 

[skier-hughes]

Put a jumper on and it will!!!!!

 

[AMc]

Really? It was 2 degrees C ouside and 17 in when I got up yesterday - that's cold enough to need the heating in my book.
Putting a jumper on doesn't make the shower any warmer so I'll still need oil for the hot water.

 

[nickc]

Very informative thread. I too have been looking at options for a 50kw heating system.

Agree with Sidd that GSHP is good in theory but doesn't make sense: the extra cost of electricity per kwh outweighing the efficiency gain (usefull site from the Nottingham Energy Partnership publishes monthly costs of each fuel type adjusted for efficiency). Also, don't forget that you're paying mortgage interest (or losing savings interest) of say 5% on the extra capital which is £500/year on £10K. This may payback times many decades (estimated 84 years in my case where capital costs were 20-30k).

My dilemma is that I can now get main gas at a connection cost of £1600 (outrageous for 50m distance but they seem to have a monopoly - any ideas?). My existing oil boiler needs replacing and a new oil tank (say £600. So a new boiler either way and the extra cost of gas connection is £1000.

Historically gas has been 25% cheaper than oil but at present about equal (see Nottingham site). Do I pay the extra £1k and switch to gas or stick with oil?
[Haven't forgotten climate change - I have done my bit by installing 2 woodburners at vast cost; solar not an option as 2* listed].

Advice from my heating engineer is that oil condensing boilers are a bit new and prone to trouble/won't last long. Non-condensing Grant and Kidd are supposed to be good though.

Looking at Honeywell or Veissman radio TRVs which seem a good idea on an existing steel pipe system, coupled with zoning for each of 3 floors. Unvented pressurized HW tank is the only way to go in my opinion (subject to sufficient water flow/pressure).

 

[Flyfisher]

[Haven't forgotten climate change - I have done my bit by installing 2 woodburners at vast cost; solar not an option as 2* listed].

I read something recently where the owner of a listed property was having trouble getting permission for roof mounted panels. They won in the end after reassuring the authorities that the installation was completely reversible, which made sense to me. Why should something that doesn't have any effect on the fabric of a building be refused? Is the pure 'look' of a roof more important that reducing energy consumption, even though the roof itself remains untouched (bar a couple of small holes and some mounting brackets - all easily reversible)?

Advice from my heating engineer is that oil condensing boilers are a bit new and prone to trouble/won't last long. Non-condensing Grant and Kidd are supposed to be good though.

Did your engineer give any hints as to what the 'trouble' is or might be?

Unvented pressurized HW tank is the only way to go in my opinion (subject to sufficient water flow/pressure).

I've been meaning to ask this question before, but this is as good a time as any; what are the pros and cons of pressurised-vs-unpressurised systems? We have a shower pump unit that creates a 'good blast' from our conventional DHW system and for everything else gravity seems to be more than adequate. It is just the shower pump that we would save or are there other advantages that I've missed?

 

[Nemesis]

Do we need to reduce energy consumption then?

The 'look' - well, yes how a listed building looks is I suppose important. Depends on the building and on a case by case basis.

 

[Flyfisher]

But the question was about the importance of the 'look' of a solar panel (given that it was non-damaging to the fabric) compared with saving energy. Few things are absolute, so how would you balance this conflict?

Or, to use two topical examples, if the Middlesex Guildhall interior is not as important as the proposed new function for the building, or if original cottage-style windows can be granted LBC for replacement with faux leaded lights, why can't non-destructive solar panels be mounted on a roof in order to save energy?

 

[Nemesis]

No idea and frankly I wonder at times why we don't just bulldoze the lot.

We could build new and shiny and so much more energy efficient.

 

[Flyfisher]

Bulldoze and build new rather than add a solar panel to the roof?

 

[Nemesis]

I wonder at times why we bother really. There are roofs and there are roofs.

Solar panels - then nice new uPVC windows ... and doors... and add some cladding to the exterior with insulation... all reversible.

 

[skier-hughes]

I'd say it would be fine to install solar panels on an area of the roof not easily visible to the general public.

WHen we have a mjority of houses with panels fitted it'll be like seeing sky dishes... or rather you rarely notice them until they've been put somewhere silly.

 

[Flyfisher]

Well, there's reversible and reversible. If you consider replacement windows to be reversible then bulldozing is reversible as well (maybe that's what you meant). Anything can be rebuilt using the same materials; I thought the idea was to preserve as much of the original fabric as possible.

 

[Nemesis]

Well, I notice sky dishes (ugly) and I notice solar panels when in the 'public realm'. Ugly too.

It's a contentious issue for which there is no simple answer.

But the Guildhall decision impoverishes us all in my opinion - and English Heritage should be ashamed.

Not of course that it was leaned on... or in any way in awe of its political paymasters...

 

[Flyfisher]

Well, I notice sky dishes (ugly) and I notice solar panels when in the 'public realm'. Ugly too.

Fair enough, but it's the inconsistency that concerns me. Shouldn't listed/unlisted buildings be treated the same when it comes to solar panels?

But the Guildhall decision impoverishes us all in my opinion - and English Heritage should be ashamed.

We can agree on that.

Not of course that it was leaned on... or in any way in awe of its political paymasters...

Sadly, I don't think it matters if these points are true or not. Whatever the real reasons the example has been set and no doubt the precedent will be cited in future cases.

 

[Nemesis]

Fair enough, but it's the inconsistency that concerns me. Shouldn't listed/unlisted buildings be treated the same when it comes to solar panels?



Er - no.

And the precedent hasn't been set in reality - all has to be taken on a case by case basis. It's not a good one though and I think that the Lord Chancellor maybe realising it now - too late.