Talk:Thermal Stores and Heat Banks

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Created article

Need better pictures and to expand text.

John Stumbles 04:31, 16 December 2006 (GMT)

Category DHW or domestic hot water

Maybe we should decide on one name for this category. The category 'Domestic Hot Water Systems' is already in use in several other articles, DHW is not. DHW will be found using the search box, so I'm not sure we need DHW as a category.

Agreed, but how does one delete a category? I've removed the Category: tag from the one article that referrred to it, and deleted the contents from the category page itself. That seems to have done it (I hope)

--John Stumbles 22:39, 1 January 2007 (GMT)

Introductory section

Thanks for the changes NT. I had not considered how this article might appear taken in isolation: it was originally part of my DHW systems article but I split it into its own article since it was so big. I can see that, taken in isolation, it needs a bit of introduction to a user coming straight to it to set the context in which they may be interested in stores & banks.

Since several of the advantages you list are already covered in the main DHW article I have referred the reader to that article instead of trying to re-state things in this one.

I left out the bits on them being more efficient, having faster recovery etc since these are not true of all such systems and anyway are discussed in detail in the article itself. I'm assuming that if someone wants to understand the technology they'll read the articles in full to do so. If they just want factoids such as 'more efficient' without any real comprehension I'm sure there are plenty of places they can go for them :-)

I also took out the glossary as I couldn't see its purpose in this article. If the reader reads the article they'll find these terms described as they are used or used with links to further information (in the hypertext way). I can see that someone may come to the wiki wanting to know what, say, the term 'plate heat exchanger' or 'primary water' is. The search function should give them some answers, including uses of these terms in other articles (such as conbi boilers and central heating systems) which they wouldn't get from a glossary in this article alone.

I can see that a glossary at a higher level (maybe in the main DHW article or possibly the main Heating or even Plumbing sections, or maybe at the top level for the wiki overall) could be useful if someone could put together - and continue to maintain - a comprehensive one. However it seems like an enormous amount of extra work when we've enough to do building the main corpus of the wiki, and if it's not comprehensive I wonder if it's worth doing at all?

By the way I also changed the heading level of your 'How They Work' section heading to 2 (2 = signs either side). Mediawiki documentation recommends not using level 1 (1 = sign) as that is reserved for the article heading itself.


--John Stumbles 15:10, 10 January 2007 (GMT)


Hi John.

I was really surprised to see you thought the article-specific mini glossary a bad idea. I don't have the sort of knowledge of plumbing as many here, and reading thru this article the first thing that stood out clearly was the need for a glossary. There are many terms used in this one that a lot of diyers wont know, and really they won't make head or tail out of it all if the terms arent explained first. I found it hard enough knowing the terms, and having no glossary just makes understanding this article 10x harder for anyone not especially familiar with DHW systems.

I know what the terms mean, but this is only because I have an interest in almost all things diy and have followed many a thread on it on ukdiy. Most readers will be new to most of this.

Also there are terms eg for the 2 sets of water that are not universal terms, and thus need definining for this article.

Saying that these meanings are all mentioned somewhere in the article is not much help because when reading a section one has nothing to refer to to remind oneself what is what. The definitions may be in there somewhere but if I have to reread it all to find a definition every time I want to understand each paragraph its going to be a nightmare trying to understand it all, and all but the masochistic will quickly give up.

Also I used the primary water definition to explain from the start that the cylinder water was the same circuit as the boiler.

You're an expert on this. Try to put yourself in the shoes of someone that knows diddly, and this article is almost incomprehensible, simply because it introduces so many concepts and jargons in one bite. Human memory is neither perfect nor instant, and explaining the terms once somewhere in the article just doesnt work. To follow it all one has to have a clear plain list of what they mean that one can refer to each time... otherwise its only of use to those that already understand a lot about the subject.

Really I think the glossary is key for anyone not already familiar with the subject. Its simply not accessible to 95% of readers otherwise, imho.


"If they just want factoids such as 'more efficient' without any real comprehension I'm sure there are plenty of places they can go for them :-)"

Well, I think thats important too. :) As a reader that (lets pretend a minute) doesnt know what is here nor what I want, all I know is I need a new hot water system, I really have no idea if this article is relevant or of interest to me. And I've not got all month to read eveything on the site. I need to know right off the bat whether this article is worth me reading, and a plain clear list of advantages at the start is exactly what I need for that. No list, no clue whether its all of any relevance. No clue, and a tough going article, and I'm gone, no incentive or willingness to read it.

Re your point that some advantages dont always apply, that can be dealt with vy splitting the advantages list into 2, advantages first, then optional advantages depending on design 2nd.

For anyone that doesnt know the subject this article is impossibly tough reading, you need to give them a reason to read it or it'll just stay on the shelf unused, like most scholarly tomes.

The hardest thing is to put expertise and accessibility together, perhaps because experts dont realise how unclued the rest of the world is. But it can be done. NT 19:40, 10 January 2007 (GMT)


OK thanks for the feedback.

Maybe it would help to point out the raison d'etre of this article. So often I've talked to clients about the various choices available to them in hot water systems and after a few minutes I notice their eyes glaze over! It's obviously all too much to take in in one chunk, so I thought I'd better write it up. That's what this attempts to be. So far I've more-or-less brain-dumped the more relevant bits of what I know, so I can understand that it's perhaps a bit much to take in and I really appreciate feedback on how it comes across and how it can be immproved. (I haven't let any of my customers loose on it yet - we'll have to see how they find it too!)

Regarding your point about the mini-glossary: I prefer the hypertext style (as exampled by wikipedia) of linking non-obvious terms to explanations of their meanings, whether that's links to other places in the same text, other articles in this wiki, or pages elsewhere on the web. I haven't done a lot of that so far, partly because few other resources exist to link to yet and I don't want to have the text littered with red links, but mostly because I haven't got A Round Tuit :-)

About the executive summary ("a plain clear list of advantages at the start") I think that's a good point, and I've changed the opening paragraph to try to convey that enough to lead the reader on.

As for the "tough reading ...scholarly tome" aspect, I hope that by explaining the subject clearly it won't be any tougher than it needs to. If it is, that's a failing of my writing which no amount of gloss(ary)ing over will remedy. But I admit I do have a prejudice that DIYers are intelligent and persevering, too! Certainly some of the most worthwhile articles I've come across on the group have been those explaining quite technical subjects in a fair amount of detail.

--John Stumbles 01:26, 11 January 2007 (GMT)


I've made a lot of changes to try to improve readability - see diff for them. In particular I've removed this bit from the 'Recovery' section since it's partly about condensing boilers (and inaccurate in places) and getting into niches which need to be covered in more appropriate extensions of this article.

excised section follows:

The temperature of the water returning to a condensing boiler is absolutely critical to whether it can condense or not. Above 56 degrees, condensation is IMPOSSIBLE (Law of Physics - Dewpoint). Different heatstores and heatbanks have the primary Flow and Return connections (to the boiler) in various positions on the store cylinder to achieve different objectives. For example, the boiler Return may be mounted 'high' to allow for the connection of a second (lower temperature) Flow / Return pair lower down for connection to a solar panel system. What benefits the solar system (stratification of the store allowing a useful temperature difference between the solar Flow and the area of the store it's supposed to heat), may also raise the average temperature of the boiler Return above 56C degrees. This will impact the boiler's efficiency.

In some cases, the effective working temperature of the store may be so high (approaching 80C degrees) that the Return will remain above 56C degrees all the time, so that there is no efficiency gain from using a condensing boiler.

One design of heatbank includes TWO boiler Return tappings on the cylinder: one part-way down, the other at the bottom. These are linked by a thermostatic mixing valve set slightly below 56 degrees, so that the boiler gets its Return water at optimum temperature most of the time. This allows a condensing, modulating boiler to reduce it's heat output to match what the store actually needs and to remain in condensing mode for as long as possible.

--John Stumbles 15:26, 12 January 2007 (GMT)

This...In some cases, the effective working temperature of the store may be so high (approaching 80C degrees) that the Return will remain above 56C degrees all the time, so that there is no efficiency gain from using a condensing boiler.

Even when set to 80C running temperature condensing boilers condense 80% of reheat time.

79.65.91.94 15:34, 29 April 2009 (BST)

This...
Thermal stores and heat banks provide hot water at mains pressure, giving excellent performance from showers and spray mixer taps. They don't require bulky tanks in the attic, which can free up space.
"Unvented" (e.g. "Megaflo") systems also give these benefits but their installation has to be notified under Building Regulations and they must be serviced annually for safety, so thermal stores are particularly attractive for DIY-ers.
Thermal store/heat banks are not equivallents to DHW only Megaflows. A DHW only thermal store or heat bank is. An integrated CH/DHW thermal store heat bank is very differnt and offers much, much more. This must be noted.

79.65.91.94 15:47, 29 April 2009 (BST)