indirect cylinders versus thermal store efficiency query

[SimonG]

An unvented thermal store, never seen one, never heard of one and can't see the need for one.

 

[Gray0689]

I was advised that a dual pump had a higher fail rate because of the dual impeller.
I have a fit for purpose hot water pump, and a standard cold water pump to me it made sense, a bit pricey for sure,
I couldnt pump into my copper cylinder for obvious reasons so it was either single pump two impeller or two pumps.
they are good quality pumps ans so far very reliable. ( 6months)

Good Stuart turner would of been better option IMO
But if it works for you then it's not wrong

 

[johnnymc]

sorry, just realised you were talking about unvented,
I have found them more prevelant than vented

 

[Gray0689]

An unvented thermal store, never seen one, never heard of one and can't see the need for one.

Lol glad someone agrees with me lol

 

[SimonG]

To me it's either unvented or it's a thermal store. Just can't see what you would get combining the two.

 

[Worcester]

Standard practice in the renewables sector to use unvented stores with multiple heat sources.

:: AKVA SOLAR - see about 3/4 of the way down using solar and biomass.

99.9% of the thermal stores we install are unvented, and the G3 regs don't apply to thermal stores....

PROPERLY designed with correctly sized thermal stores and properly sized heat supplies (back up boiler if primary heat source is a back boiler wood burning stove..) you'll never have the fight over heating or hot water, thanks to stratification, baffling, flow and return positioning and the correct use of direct and indirect approaches, sometimes with external plate heat exchangers. That way you never have a shortage of hot water or heat. It's also why we never (and you shouldn't) simply walk in to pb or pc and buy an x00 litre thermal store.

You don't need hot water tank at all this way..

 

[Gray0689]

Standard practice in the renewables sector to use unvented stores with multiple heat sources.

:: AKVA SOLAR - see about 3/4 of the way down using solar and biomass.

99.9% of the thermal stores we install are unvented, and the G3 regs don't apply to thermal stores....

PROPERLY designed with correctly sized thermal stores and properly sized heat supplies (back up boiler if primary heat source is a back boiler wood burning stove..) you'll never have the fight over heating or hot water, thanks to stratification, baffling, flow and return positioning and the correct use of direct and indirect approaches, sometimes with external plate heat exchangers. That way you never have a shortage of hot water or heat. It's also why we never (and you shouldn't) simply walk in to pb or pc and buy an x00 litre thermal store.

You don't need hot water tank at all this way..

How does a unvented thermal store pass building regs?

 

[Gray0689]

How does a unvented thermal store pass building regs?

Thanks for link Worcester I'll have a look

 

[Howsie]

Hi Worcester. Thanks for the post, Fair comment, which is one of the reasons i prefer to plumb it myself, there are a number of different ways to approach the system, all of which would work, there is no hard and fast rule, Any plumber i might choose would be a lucky dip, and would have his own way to do things,
In the heel of the hunt, I haven't started yet so i will always have the option to contract a plumber if i believe i am so far out of my depth,
I would prefer a consultant rather than a plumber, but everybody wants to install their own systems, I have been looking for a " heating system designer" on the net, but no body posts this up as an optional service.
I was planning to put a heat dump radiator off the stove in my kitchen, as its fairly easy to get to with the larger pipe size it will require.
the Ecocat looks interesting, I was moving towards a unit like the Gledhill Torrent green heat, although ive seen some comments to stay away from this unit on the forum,
My stanley Oil stove is also a cooker and we run it to heat the kitchen, like an Aga. but im thinking with a heat sink from the wood stove in the kitchen, it might be an expensive way to cook during the winter,
Im hunting around here in ireland to try and find something similar to avoid having to ship from the UK. The stove supplier is in the UK so will ship that for sure. the strange thing is that often i can find things and ship from the UK for less than i can buy them here!! only time will tell.
I appreciate your support.

What's the difference between a consultant and a plumber? I know the answer but I don't think you do.

 

[Ermintrude]

Advised him to hire a designer! M&E consultants are everywhere. Probably charge 5k. Including commissioning.

Designers design , fitters fit. Have a go Henry's .....

Points are valid but think bloke is over spec and under engineered.

Seems like wants to wash and bathe whole of Ireland in one go and heat the water from two candles and a energy from a wind toy.

Don't think a thermal dump is going to be required, as soon as demand is satisfied switch over the the steam turbines and let the 6mW rip.

http://www.carbontrust.com/media/129472/ctc810-insights-into-biomass-heat-installations.pdf

 

[johnnymc]

think ill put a "Forum coil" in the tank and use that!! that should heat the UK as well and i can probably export the surplus to russia, i hear its really cold there in the winter.
But seriously, I understand the advise to use a plumber, i take it fully on board and understand its well meant and good advise.
If i knew a good plumber, specialising in this field, who i trusted and could afford, id use him.

Yes i am under engineered, thats why im here.
If as professionals you dont want to give advise to Henry, why allow Henry to join the forum?

My questions are as follows,

Indirect cylinder versus Thermal store ? if the size of tank is to be the same, 350 to 450 liters, are there REAL advantages ( economy, heat management etc) in choosing one over the other?
If i use a thermal store with a plate heat exchanger, can they handle the pressure and flow rate of a 3bar pump? is there a make or type i should consider?
What size heat sync should i consider to dissipate heat in the eventuality of power failure?. the heating circuit is 3/4 inch with 1/2inch spurs, all on one level. i was planning to run 1inch to the sync, which will be below the stove by about 1ft and 15ft away
Do you consider, given the unit cost, that it would be economical to consider retro fitting a laddomat on my oil stove while im at it?
Given i will have a solar coil in the tank before solar is installed, should i put fluid in the coil or will it be OK open until solar is installed. if so what fluid?

I would appreciate if we could move beyond the fact that I'm a tosser who doesn't know what he is doing and should employ a plumber!!

thanks in advance.

 

[Ermintrude]

Not a tosser at all! Tossers don't ask for advice.

U could use solar coil in series with other coil as would just speed up recovery. Will need a good clean if solar fitted. Don't cap leave open with plastic caps to keep dust and rubbish out if not using.

ACV has no coils!

ACV SLME 400l Or slimline sl? ? But speak to rep and they will help with spec and design for free.

Not 100% but slimline sl can go vented?

 

[Dotty]

Just reread that.

Telling off retracted.

 

[Gray0689]

Not a tosser at all! Tossers don't ask for advice.

U could use solar coil in series with other coil as would just speed up recovery. Will need a good clean if solar fitted. Don't cap leave open with plastic caps to keep dust and rubbish out if not using.

ACV SLME 400l ? But speak to rep and they will help with spec and design for free.

Acv expensive but defiantly the best

What your doing ain't for the faint hearted but if you think your upto it good luck
Keep us informed
What part of Ireland you from
At least you not got the regulations to worry about

 

[Ermintrude]

Sync should be 28mm min and above I think !

 

[Worcester]

How does a unvented thermal store pass building regs?

Sorry my mistake in explanation, they do need to, and thanks for questioning it 🙂 There are special clauses in Part G for both vented and unvented thermal stores, the difference is that for various reasons, the installers (though we do anyway ...) don't have to hold a G3 unvented certificate.

It's because the stores don't have a way of automatically replenishing the water (fluid) in them - they are a sealed system, as such they are considered a part of the central heating system. (They do tend to have large expansion vessels attached 🙂 ) and also inherently they don't have temperature relief valves for the same reason. (pressure release yes, temperature or combined temperature and pressure - no )

Note: In johnnymc's particular instance because he has an uncontrolled heating source - the wood stove, then some part of his system will need to be vented, the easiest way may be to connect it directly and use an vented thermal store (he still gets 'mains pressure' hot water of course) and of course (already presumed this was 'understood') - he'd need to fit a tmv on the ho****er outlet - there are other ways though to still be compliant and of course in Ireland the regs may be different anyway.

With biomass, heat pumps, solar thermal, gas and oil boilers (condensing and not in some cases) et al in a multi fuel environment, there are only a very few people out there that fully understand how to design an effective system with all the correct requirements on flow and return temperatures, then add in the metering requirements for the RHI and you've lost >99% of the boiler fitting companies out there.

 

[Gray0689]

Sorry my mistake in explanation, they do need to, and thanks for questioning it 🙂 There are special clauses in Part G for both vented and unvented thermal stores, the difference is that for various reasons, the installers (though we do anyway ...) don't have to hold a G3 unvented certificate.

It's because the stores don't have a way of automatically replenishing the water (fluid) in them - they are a sealed system, as such they are considered a part of the central heating system. (They do tend to have large expansion vessels attached 🙂 ) and also inherently they don't have temperature relief valves for the same reason. (pressure release yes, temperature or combined temperature and pressure - no )

Note: In johnnymc's particular instance because he has an uncontrolled heating source - the wood stove, then some part of his system will need to be vented, the easiest way may be to connect it directly and use an unvented thermal store (he still gets 'mains pressure' hot water of course) and of course (already presumed this was 'understood') - he'd need to fit a tmv on the ho****er outlet - there are other ways though to still be compliant and of course in Ireland the regs may be different anyway.

With biomass, heat pumps, solar thermal, gas and oil boilers (condensing and not in some cases) et al in a multi fuel environment, there are only a very few people out there that fully understand how to design an effective system with all the correct requirements on flow and return temperatures, then add in the metering requirements for the RHI and you've lost >99% of the boiler fitting companies out there.

That's what had us confused we was taking about a stove from the outset uncontrolled heat source that's why we was saying vented

 

[SimonG]

It makes sense now. Cheers.

 

[bennygas]

Hello there, sorry to interrupt - haven't been on here for ages, but nice to be back. Couldn't help but find this business about part g and thermal stores etc interesting - it was something that bothered me in work going back a while so I ended up looking into it a bit. This kind of summarises what I ended up thinking on the matter....


Building Regulations requirements G3 (2) and (3) apply to all stored hot water - including primary vessels, thermal stores, accumulators/buffers in all buildings, irrespective of how they're heated - and that goes for sealed systems and mains fed systems (the only difference is in the prescribed nature of the energy cut out serving the vessel and the use or not of a tprv). The only exception is where the hot water storage is part of an industrial process.


it could well be a bit of a problem for the renewables sector if it did but realise it - my perception is that many seem unaware of the implications of part g (everyone I speak to seems to think its all just about megaflos etc - but it really is quite far reaching). I dare say the building regs will be updated at some point to take into account the changes that have occurred in the technologies being plumbed in to big tanks, but until then, strictly speaking, a lot of biomass stuff for example, doesn't comply with part g.