Thermal store or not?

[DeltaT2]

Now, if you want to show yourself up then carry on responding to what I didn't write. If you want to be useful, then try writing something positive instead of looking for ways to slag people off.

I didn't say you can't have a gravity system IF your building layout is suitable. In fact I specifically have allowed for that if you care to read what I wrote.

But I strongly suspect that the OPs building wasn't conveniently designed to make a fully gravity system practical. I don't know, you don't know (we haven't been given any specifics about the building), and the OP won't know either based on your posting nothing but complaints about what other people are writing.
Note that word, practical - it may well be possible to design a system that works with next to no height in which to create the pressure difference that will drive the syphon; but if that then requires pipes of a size and/or layout which can't reasonably be fitted in the property then it's not a practical system.

We don't even know that the only location for the store is above the stove. We can guess that it probably is, but we don't know. Now, can you explain how to make a system that will thermosyphon to a cylinder that's below the heat source ?


As an aside, non-pumped systems (and the difficulty of finding a competent plumber) came up in conversation at home only the other day.

Listen mate, your posts are detailing grossly over-engineered drivel & full of contradictions. You don't know what you're talking about.

 

[LondonChap]

Of course you can design & install any system to operate on a complete gravity system, both HW & Radiators;

That is not 100% true. The heat source has to be below the radiators and cylinder and horizontal pipe runs not very long at all, otherwise it does not work. That I do know.

B.llox mate, you don't know what you're talking about either.

I know how thermo-syphonic systems work for sure. It is best you give up now

 

[SimonH2]

Listen mate, your posts are detailing grossly over-engineered drivel & full of contradictions. You don't know what you're talking about.

I'll (metaphorically) throw down the gauntlet :

1) Please point out where the inconsistencies are in the text you quoted.

2) Please sketch out a thermosyphon system where the hot water will go downhill to a cylinder that is below the heat source. Lets keep it simple, forget about radiators, just a simple heat source (could be a wood burning stove) and a cylinder of hot water.

Since I apparently know nothing at all, this should be educational. Naïve me always thought they put hot water cylinders higher than the back boiler for a reason - seems I was mistaken (that's sarcasm in case it's not obvious).

I know you won't rise to the challenge - so far, every single post you've made to this thread has been to criticise others without adding anything whatsoever that is actually contributing to the OPs questions.

 

[gaswizzard]

The heat source has to be below the radiators and cylinder otherwise it does not work.

Not true.

That I do know.

No you don't.

 

[LondonChap]

The heat source can be above the radiators and cylinder in a gravity system? Are having a laugh?

They have a problem working being level, if they do work at all. As a kid, I saw an old pub in which the heat rose up a few flow pipes from the oil boiler on the ground floor, one in each corner of the pub, deliberately cooled in the attic, and then the cooler water dropped down a few more return pipes on the far side. The tall column radiators were stabbed into each pipe, either flow or return. It may work like that even with the boiler above the radiators. But expensive heat is wasted in the attic to move the water around.

All I have seen, apart from that old pub, had the stove or boiler below all.

 

[gaswizzard]

We seem to have a couple of old school guys in here who are capable of designing the gravity system , maybe you guys could confirm some circulating pressures for me.

Circulating height between boiler/heat emitter = 6 metres.
82c flow
60c return.

 

[LondonChap]

I could show you how to site a HW cylinder at the same level as a boiler,

I have seen them on old cast iron Ideal Concords, where the return connection was very low on the boiler. But the radiators were pumped.

The only way I know of how to get the heat source above the radiators is in the example I gave, and then you waste heat in the attic to do it. You could even have the boiler on the 1st floor. The speed of the flow must depend on the heat dissipated in the attic.

Maybe you know another way. Spill the beans.

 

[gaswizzard]

The only way I know of how to get the heat source above the radiators is in the example I gave, and then you waste heat in the attic to do it. You could even have the boiler on the 1st floor. The speed of the flow must depend on the heat dissipated in the attic.

Waste heat? , what has the 'attic' got to do with anything?

Maybe you know another way. Spill the beans.

Looking up 'density of water' should give you a clue , then again you should know this otherwise you shouldn't be giving advice on the matter......and yes a radiator fed by gravity will work perfectly well when situated below the heat source.

 

[LondonChap]

Waste heat? , what has the 'attic' got to do with anything?

It is cold up there, cools the pipe and water, and it drops down the returns on the others side. The rads on the flow riser were always far hotter than those on the turn drops.

I am not giving advice. I am telling you what I saw, which you could not understand, but the Victorian fitters did when it was an old coal boiler (converted to oil by a burner on the front).

 

[LondonChap]

We seem to have a couple of old school guys in here who are capable of designing the gravity system , maybe you guys could confirm some circulating pressures for me.

Circulating height between boiler/heat emitter = 6 metres.
82c flow
60c return.

If it is vented then the pressure will drop accordingly from a 6 metre head to zero in the pipes.

 

[gaswizzard]

We seem to have a couple of old school guys in here who are capable of designing the gravity system , maybe you guys could confirm some circulating pressures for me.

Circulating height between boiler/heat emitter = 6 metres.
82c flow
60c return.

If it is vented then the pressure will drop accordingly from a 6 metre head to zero in the pipes.

Can I have the answer in mbar please. not sure what the 'vented' part of your answer means?

 

[SimonH2]

2) Please sketch out a thermosyphon system where the hot water will go downhill to a cylinder that is below the heat source. Lets keep it simple, forget about radiators, just a simple heat source (could be a wood burning stove) and a cylinder of hot water.


What!!!??? Are you completely mad!! Plumbing & Heating I can design & install, but changing the laws of physics, well that'll take a wee while to do - even for my good self...............
Get a grip mate, nobody said the HW cylinder or thermal store was going down below the boiler level............Now you're just making it up to try & save face............

Now don't be a bampot & a complete tozzer, admit you're out of your depth & know f.ck all about the subject.........

Thank you for proving exactly what I said. You were quite adamant that the OP can do what he wants with no electrics and no pump. Now, unless he's communicated that to you privately or you otherwise know the arrangement of his house, you cannot know that his cylinder isn't in a cellar or otherwise below the height of the stove. So without knowing what the arrangement is, you state quite categorically that convection will work and anything else is grossly over engineered.

What I said is that we don't know what the OP's arrangement is, so we can't know whether it will support a convection setup or not. It may do, it may not do. So as I said, IF his general arrangement supports it then he can use convection, if not them it'll have to be pumped.
In any case, whether it is the best arrangement also depends on his priorities. If there's

Note that you claimed a simple pumped loop is "grossly over engineered", yet now you have to admit that it may actually be required. Until we know the layout of the building then that can't be answered. But of course, you don't seem to care about trying to help the OP, you seem more intent on being ever more abusive to those that are.


EDIT: and no I look back, lets see what the Op said in his very first post :
Relying on gravity-feed only isn’t an option as the pipe runs will have to run up-down-and back up again in some places.
Now I know that given the right conditions, you can get a gravity system to work where part of it is "upside down", but that quote does suggest that a pumped system is highly likely to be more appropriate.

The OP also mentions "we", so more than one person in the property. That means any system has to take into account the other occupants. Some people will be happy with a system where they have to "know how to work it" for it to work properly - many others will not be happy with anything where the manual involvement goes past feeding the wood in.

And no mention is made of the type of property. So we don't know if it's a grand house with 5 floors including a cellar (great for convection), or some sprawling building on one level (not great for convection). Surely you have to agree that these are somewhat important details if you are going to design a system for it ?

 

[LondonChap]

Can I have the answer in mbar please.

0.6 bar to zero down the pipe. . Work it out from that.

not sure what the 'vented' part of your answer means?

open to the atmosphere. If you can't figure that out..well......!@#*(&@#?

 

[gaswizzard]

0.6 bar to zero down the pipe. . Work it out from that.

Seems your struggling with the answer , I asked for the "circulating pressure" , this being in proportion to the temp difference between flow/return , the answer being 6.2 mb.

What is an 'open vented' system?

I think I know what 'one of those' is.

 

[LondonChap]

Seems your struggling with the answer ,

Nope. You just look here and graphs and all.....

http://www.engineeringtoolbox.com/gravity-heating-systems-d_189.html

The problem with you is that you think you are cleverer than what you are. Also, your question was irrelevant to what was being discussed.