Boilermate - "efficient"?

[BenBag]

As per title, I have a Boilermate in my flat which works well and provides oodles of hot water 24 hours a day.

However, I'm a sad single bloke, I don't use all that much hot water (I shower, honestly) and my gas bills are huge. The manual for the boilermate states a number of times that it is "most efficient" not allowing the heat store to cool down.

So, 2 questions,:
1. The boilermate seems to be internally insulated, but still gives off a fair amount of heat. Is it worthwhile putting an external jacket on it?

2. The manual also shows me how I can wire in a timer to shut the hot water function off (e.g. overnight or while I'm at work), making it a lot more like a conventional system. Again, this comes with a warning about efficiency. Has anyone tried this, or is there any hard information about what "more efficient" actually means?

I'm probably going to add the timer then watch my gas usage at the meter over a couple of weeks, just hoping to get some other people's experiences.

B.

 

[gas4you]

Their term 'efficiency' relates to the amount of hot water it provides, not how much gas it saves.

Personally in terms of gas usuage I think they are very inefficient with the boiler having to be set on max as per the boilermate instructions

 

[RichThompson]

First of all I would say that you are lucky your Boilermate works But I'm amazed someone (builder?) thought it was a good idea to install one in a flat. My 3-bed end terrace had one when I moved in and it was far too big for the purpose.

I agree that no matter how little hot water you actually use, your bill will always be high with one of these things. You could certainly try using a timer to shut it off to see if your bill goes down. When the timer turns it back on it will burn gas for some considerable time until the set temperature is reached. You might save a small amount of money at best.

If you own the flat and can see yourself staying there a while it might be worth considering a combi boiler. My direct debit almost halved when I had my boilermate replaced.

 

[mickyg]

Boilermates or thermal stores in general, are usually only efficient in large setups with condensing boilers, where the amount of heat lost from the store is more than made up for in elimination of boiler cycling, and the fact you can use a smaller output heat source. Also with high usage as well they can be very efficient, and for multifuel purposes are about the only decent solution. For anything smaller than a 5 bedroom house I would say they're an absolute waste of space and gas. Gledhills are notorious for problems.

 

[BenBag]

Thanks for all the comments!

I'm actually quite pleased with the thing, apart from all the residual heat and the huge bills of course

Everyone on the development has a boilermate fitted, I expect we do not do well in terms of gas usage.

I expected there was some meaning to "efficient" I hadn't considered. For now I'll fit the timer (£1 off ebay, whoo!) and see what that does, will post back in a couple of weeks...

B.

 

[JohnD]

are all the pipes well insulated?

I've only got an ordinary cylinder, but since I had it replaced with a foam-lagged one, and fitted the two fibreglass jackets to it from my old one, and put climaflex lagging on all the pipes (including to/from the boiler and taps) it loses so little heat that the airing cupboard is so cool that it hardly keep the clothes dry.

BTW if you want to add insulation, the white loft quilt, made of recycled plastic bottles, is much cleaner and is itch free, as it does not shed fibres and dust like the old fibreglass stuff.

OOI, with all this insulation and my whizzo new (conventional) boiler, my summmer gas usage is now only 0.6m/day which is about 6.6kWh/day. Last year it was 12 kWh/day with the old boiler so I am quite pleased.

 

[Fluffster]

Boilermates are very efficient. Cranfield university did tests on thermal storage at concluding they are around 15% more efficient.

15% more efficient than what? boiling a kettle?

Pete

 

[GeorgeBramwell]

15% more efficient than what? boiling a kettle?

Than directly heated rad systems. Search the uni's site.

 

[D_Hailsham]

Cranfield university did tests on thermal storage

Can't find anything on Cranfield's website. Do you have a link?

 

[GeorgeBramwell]

Do you have a link?

Applied Energy Group, School of Mechanical Engineering, Cranfield Institute of Technology, Bedford MK43 0AL, UK

Cranfield Institute of Technology and British Gas plc have undertaken a collaborative programme of tests of a system which interposes a heat store between a boiler and a distributive central heating network. This has culminated in a field trial at Spa School in London. It was predicted to lead to significant energy savings, to a lower installed boiler capacity requirement, and to reductions in installation costs for new and for some retro-fitted systems. Specifically, a thermally insulated 3235 1 hot water store was installed in the circuit between the existing modular boiler set and the hydronic ‘radiator’ network. The pipework was arranged so that the heating system could be operated either as configured originally or in the storage mode, in which case two of the five modular boilers were valved off. The two configurations were operated alternately (for four week periods), and their performances were carefully monitored over the 1985/86 heating season.

The storage system performed successfully with a 40% lower installed boiler capacity. Boiler cycling was reduced by a factor of 15 and the mean boiler load factor rose from 37 to 70%. Analyses of results show that a 6% saving in annual fuel consumption was achieved by the storage system as compared with that of the highly efficient conventional system employing direct external compensation of the boilers. However, all this saving is attributable to the faster building preheat achieved with the store as, surprisingly, the annual efficiencies of the two systems were the same (in contradiction to the findings of other trials). The reasons for this are examined. Where direct compensation is not possible, the reduction in boiler cycling demonstrated will lead to a further substantial efficiency advantage of at least 10%.


http://bse.sagepub.com/cgi/content/abstract/8/4/79

• 6% fuel reduction
• further 10% because of boiler cycling elimination
• Boilers 60% less in capacity.

Sound impressive to me - at least 16% better in fuel efficiency. The conventional system was direct weather compensated as well.

Put in an Avantaplus condensing boiler, which can heat the CH section of the store directly to weather compensation and savings are even greater.

You install a pretty small boiler and get away with it, saving a packet.

As I say some nutters here haven't a clue about heating systems.

 

[JohnD]

As per title, I have a Boilermate in my flat which works well and provides oodles of hot water 24 hours a day.

However, I'm a sad single bloke, I don't use all that much hot water (I shower, honestly) and my gas bills are huge. ....

but

...Cranfield Institute of Technology and British Gas plc have undertaken a collaborative programme of tests of a system which interposes a heat store between a boiler and a distributive central heating network..
... surprisingly, the annual efficiencies of the two systems were the same (in contradiction to the findings of other trials)....

I suppose a hot water system is, in some ways, very similar to a central heating system

but looking at the referenced article I can't see that it sheds any light on the efficiency of BenBag's Boilermate

 

[Deleted member 105431]

A "spa school" and a flat are two very different heating loads. GeorgeBramwell is a cut and paste clown.

 

[JohnD]

I just spotted

...performances were carefully monitored over the 1985/86 heating season. ....

where are the more recent studies?

 

[Deleted member 105431]

I just spotted

...performances were carefully monitored over the 1985/86 heating season. ....

where are the more recent studies?

that's only 20 years ago!, and a case study of a school opposed to the small flat the OP lives in.

What do you expect from DrDrivel?!

Give him time to cut and paste something else out of date and totally irrelevant.

George you are the laughing stock of this forum whatever alias you hide behind.

 

[doitall]

A "spa school" and a flat are two very different heating loads. GeorgeBramwell is a cut and paste clown.

You don't think Dr Drivel