Accumulator - benefits?

fezster · 22 May 2016

I've been seeing posts mentioning accumulators for a while, and always dismissed them as I assumed they were only needed if your incoming pressure/flow rate was inadequate. I have great incoming pressure (at least 4 bar) and great flow rate (50 - 60 l/min). However, I notice a drop in shower performance when >1 shower is used at the same time. See my post here:

//www.diynot.com/diy/threads/a-question-on-shower-performance.443168/

Then I came across this link in another post:

http://www.gah.co.uk/downloads/GAH-coldstream-2010-Feb.pdf

and it mentions the benefits of an accumulator when using more than one outlet.

Could someone confirm if my understanding is correct that this could benefit even if you have great pressure and flow rates? And perhaps provide more information as to exactly how it benefits.

Thanks.

fezster · 22 May 2016

Also just noticed on the same thread that the link to GAH was removed because of spam etc. So perhaps ignore that. My question still remains, though

Dan Robinson · 22 May 2016

Can't post details at the moment, but you can see the difference.

fezster · 22 May 2016

Great demonstration, and think it will benefit my usage. Look forward to the details when you have a chance. Thanks.

bernardgreen · 23 May 2016

A accumulator can only provide an increase in flow rate for as long as there is water stored in the accumulator. It cannot increase pressure though it may appear to do so due to the increase in flow from taps that occurs while the accumulator is able to add additional water to the incoming flow. It can only sustain pressure. When the acumulator is empty then the flow rates at taps will drop and dynamic pressure at taps and appliances will drop.

From the Coldstream document, cut and pasted and with my red underlining added

hazetimesfive · 23 May 2016

60lpm and you notice a drop in performance with two showers running? must be taking your skin off.

fezster · 23 May 2016

They are 30l/min showers at 3 bar.

Dan Robinson · 23 May 2016

I think the point being made its that if you have 60l/min iconic, then an accumulator will do little to help. If you want more water you'll probably have to up the pipe size.

Dan Robinson · 23 May 2016

Right, in my clips, we installed a 300 litre accumulator an unvented cylinder in a garage, effectively reversing the direction of flow in the house as the bathroom was above the location we worked in.

The house had a small Alkathene mains supply buried god only knows where, and a 15mm copper supply into the garage for an outside tap.

We hijacked this and fed the whole array.

The performance difference is easy to see.

The size of the vessel is key, but being able to add additional ones on is always a feature we sell, partly to keep the installation cost down and partly to cover our backside as customer expectations can change mighty quick when the invoice lands. So I always sell these things as a modular system.

As Bernard points out, once the vessel is depleted you are back to whatever the mains provides as can be seen in my video when the bath fills up and the flow drops to a very low level.

That system takes about 45 minutes to recharge fully with no further drain off.

Will be interesting to see how long the vessel lasts, although the bladder is changeable.

@simond also fits a fair few of these, although I believe he prefers the official TWS products rather than the cheaper alternatives.

TWS don't like the fact that people like me will make an accumulator system up as they think they have a patent on the technology.

fezster · 23 May 2016

Dan Robinson said:
I think the point being made its that if you have 60l/min iconic, then an accumulator will do little to help. If you want more water you'll probably have to up the pipe size.

This is what I'm struggling with. Is it that the shared pipework to the 2 showers cannot cope with the demand, in which case an accumulator will not help, OR is it that the mains isn't able to cope, in which case the accumulator will help.

To test this, I was thinking of running the shower and then turning on an outside tap on a completely different circuit. The tap is before my PRV, if that matters. If the flow to my shower on it's own circuit drops, then it is the MAINS dynamic pressure/flow which is the problem and the accumulator should solve that? Is this the best way to test this?

No longer responding on the other thread, and will continue on here.

fezster · 23 May 2016

Dan Robinson said:
TWS don't like the fact that people like me will make an accumulator system up as they think they have a patent on the technology.

Are you saying you literally *made* your own accumulator? I was led to believe they are fairly cheap to buy anyway. What's the cost difference in buying and making a 300l accumulator.

And I was reading about the actual amount of water stored vs the capacity of the accumulator. How can this be calculated?

Dan Robinson · 23 May 2016

Where have you measured this 60 l/min?

Dan Robinson · 23 May 2016

I didn't make the accumulator, I made my own "package".

fezster · 23 May 2016

Dan Robinson said:
Where have you measured this 60 l/min?

This was quoted to me by the guy from the water board who fitted my new water main. It is 32mm MDPE. I think I need to do an actual test from multiple outlets.

Dan Robinson · 23 May 2016

Indeed - sounds like that was the open end flow rate at your connection rather than anything in the house, and for London, that is still pretty damn high.

diynot

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Accumulator - benefits?

Similar threads