Linking Boilers.

[Norcon]

What the Op needs is one large boiler and buffer tank.
This paper explains it.............(should keep you all quiet for a while)


http://www.patkelco.com/uploads/files/4bf77cff8bc8411bb00c67e962d0ef7d.pdf
No smart comments about sludgebuckets please.

If it was my hall Doitall this would be your design brief.
Above is theory!
Below is reality!
The question is "Could you deliver?"
Image removed.

 

[doitall]

First you are taking different temperature zones, so a different ball game altogether. The Op is looking for a demand ranging from say 3kw to 45kw.

A couple of interesting bits in the paper you linked to.

All of the following examples ignore at least one of two engineering facts. Fact #1: if you put energy into a
system, it must be carried away from the point of input at least as fast as it is being introduced. This means that the designer must consider the relationship between a system’s minimum energy consumption rate and a boiler’s minimum heat output. Where the boiler’s minimum heat output exceeds the system’s minimum heat consumption rate, something must be done in system design to create a balance. Fact #2: energy wants to do work, so there must always be a minimum water mass available for the boiler to work on. Remember too that
boilers can’t read blueprints; they do what systems make them do, not what you want them to do.

Final Considerations

1. Understanding the energy effect of short-cycling is sometimes made easier by thinking of the issue in terms of the boiler’s operating cycle. During pre- and post-purge, the boiler is a reverse heat exchanger that takes heat from the system and throws it up the chimney. When the flame is established, the boiler first replaces this purged energy and then replaces the energy consumed by the heating system. The higher the percentage of time spent turning on and shutting down, the higher the percentage of total heat that goes up the chimney.

2. Light load devices are often found in fire pump systems, house pump systems, and chiller plants. Walk into a boiler room and what do you see? The boilers are all large, all the same size, and all too big for the micro loads. Why don’t we use jockey boilers? It seems that the boiler plant is the only building mechanical system that does not include a light load machine. It’s time to change that and make a light load boiler a standard part of every boiler plant.

3. Some engineers have reminded us that there will be radiation and convection losses from the buffer tank (if one is required by the system), and that this represents a permanent parasitic energy loss. That’s true; but the energy savings achieved to date have been so dramatic that we now dismiss this objection as unimportant. Remember that improving cycle efficiency produces savings of 15% to 50%, and often more. If the cost of
achieving this is a 0.25% loss at the tank, it’s a price that should be paid. Remember too all of the secondary advantages identified above. It is certainly possible to design a system that connects the buffer tank to the
system only when it’s needed, only during times when the system does not provide a “home for the heat,” but doing so adds cost and complexity, and the owner’s future fuel bills will depend upon the understanding and skill of the service technicians who will come and go in the years ahead. It is likely that many of them will not understand what the system does, why it must do it, how it does it, and how to optimize its performance. We
should pause and reflect before giving up the bullet-proof characteristic of the approach proposed here.

4. This approach is bullet-proof: it works no matter whose equipment gets purchased by the contractor.

Do read the Final consideration Norcon, he is dis-agreeing with your one large boiler, and so am I

Smaller boilers will cycle far less than one large one, indeed he shows multiple boilers in most of his article.[/b]

 

[Norcon]

Patterson-Kelley wrote

All that’s important is that the system connections be made as shown in Figure 13:

Can you deliver Doitall or do I look for someone else?

 

[doitall]

What are you asking Norcon and I bet a pound to a penny the expansion vessel is undersized in your pic.

If you want me to do the job, No chance, the kits is mothballed.

 

[Norcon]

What are you asking Norcon and I bet a pound to a penny the expansion vessel is undersized in your pic.

If you want me to do the job, No chance, the kits is mothballed.

Its obvious from your replies that you don't understand what Patterson-Kelley are proposing.
Does BUFFER cylinder separating the CH and boiler ring any bells?
I shall look for someone else who understands the design brief and can deliver the goods.

 

[kevplumb]

I shall look for someone else who understands the design brief and can deliver the goods. icon_rolleyes.gif

1DIA never offered to do it

2 your hilacking the post

3 when did industrial come under DIY

 

[doitall]

It's obvious from your post you'll believe anything, other than some American outfit who are they.

During pre- and post-purge, the boiler is a reverse heat exchanger that takes heat from the system and throws it up the chimney. When the flame is established, the boiler first replaces this purged energy and then replaces the energy consumed by the heating system. The higher the percentage of time spent turning on and shutting down, the higher the percentage of total heat that goes up the chimney.

Obviously they don't know much about condensing boilers.

2. Light load devices are often found in fire pump systems, house pump systems, and chiller plants. Walk into a boiler room and what do you see? The boilers are all large, all the same size, and all too big for the micro loads. Why don’t we use jockey boilers? It seems that the boiler plant is the only building mechanical system that does not include a light load machine. It’s time to change that and make a light load boiler a standard part of every boiler plant.

Obviously you don't understand their Final considerations.

If you want me to comment on buffer tanks, thermal stores or sludge buckets, just say so.

On the same subject, what advantage would I get heating a 200Ltr buffer tank to 85c, to heat 2 rads in the snooker room with a total water content of 12Ltrs.

Answer an 2000% increase of running cost

 

[Norcon]

Doitall wrote

If you want me to comment on buffer tanks, thermal stores or sludge buckets, just say so.

Feel free but since the most you understand about them is that they sludge up Im hardly going to learn anything?
As for your 2000% that rubbish.

 

[doitall]

Doitall wrote

If you want me to comment on buffer tanks, thermal stores or sludge buckets, just say so.

Feel free but since the most you understand about them is that they sludge up Im hardly going to learn anything?
As for your 2000% that rubbish.

What figure would you put on it then.

12 Ltrs at 65c

V

200 ltrs at 85c

You're not considering the large difference in the heating load, and neither is your mate in the States, except right at the end he says.

Walk into a boiler room and what do you see? The boilers are all large, all the same size, and all too big for the micro loads. Why don’t we use jockey boilers? It seems that the boiler plant is the only building mechanical system that does not include a light load machine. It’s time to change that and make a light load boiler a standard part of every boiler plant.

Small is good, two small will beat one large any day, and even more so when the heating load is so diverse.

 

[bengasman]

Would the rgi who is going to install this not be the best one to judge what would work as he will be the one correcting things under warranty if they don't work?

No I don't, 90% of domestic heating engineers wouldn't know where to start.

Don't you think he would possibly not be best pleased if a layman were to tell him how he should do his job?

That's what design engineers and consultants are for.

And if he did follow your design and it does not work accurately, would you pay him to redo it or expect him to absorb the cost and alter it free and for nothing?

If the installer is unhappy with any part of the design he should say so and get a variation order, Drawings are indicative, not a Bible.

Is there another thread about this subject?
I could not find anything from the op indicating there is a designer involved, and judging by his questions he does not know a lot about heating himself.

Interesting point of view that the installer would probably not know where to start, but if he follows orders, because he does not know how to do it, and it doesn't work, then he is supposed to correct things at his expense because he followed orders.

 

[doitall]

I don't think the Op knows anything, which is probably why he asked the question, whether he intends to get a competent engineer in to do the job properly or intends a diy job I have on idea.

A village hall is an unusual installation because of the way they are used, different areas requiring different temperatures at different times, get it wrong and it will cost a bomb to run or freeze you to death.

As I said I doubt a domestic installer would be up for it.

If the installer is working to a design and drawing by others, then any alterations, modification etc in the design is chargeable as an extra.

 

[heatingman]

Well I have just read the pDF from the "USA", get all the way to the end and it recommends the low loss header approach. Its been around for years, works brilliantly and is the preferred method for Keston's.

 

[Norcon]

Doitall wrote

What figure would you put on it then.

12 Ltrs at 65c

V

200 ltrs at 85c

Try reversing your figure. Yes your 12 ltrs probably increases 2000% more in cost than heating the 200 ltrs.
Why?
Because the 12 ltrs is being circulated through heat emitters where as if you look at my earlier image the 200 ltrs circulates through a highly insulated buffer cylinder with outdoor reset applied to the circulating temperature.

 

[doitall]

Mine calls for heat, the zone valve open, the highly efficient condensing boiler fires up and sends the heat straight into the two heaters, within minutes the room is up to temperature and the rooms stat shuts the zone valve off along with the boiler.

And don't come the old heat emitters, highly insulated buffer cylinder bit, the same boiler heats your 200Ltrs that heats my 12Ltrs, the only difference is you had to heat an extra 188Ltrs, and lets not forget at an extra 20c.

Of course buffer tanks have a place, especially with solar and multifuel installations, as well as controlled temperature zones, but not in a variable occupancy building.

A store in this case is like boiling 200Ltrs to make a pot of tea.

 

[Norcon]

Never mind. You just don't get it.