Thermal store advice

[ianmcd]

If you have 210 liters in an unvented cylinder heated to 60c and dump the entire contents into a bath (until empty and full of air) you have 210 liters of hot water @ 60c. Or just about.
If 10 bathers are lined up for a bath the final person should still have a hot bath.

If you have the same in a thermal store you cannot dump it into a bath because it is primary water, full of additives.
So you have to transfer the heat energy through a heat exchanger via a separate cold supply. Usually a cold water tap.
And the bath won't have anything close to 210 liters of 60c hot water when you go through that inefficient process.

The maximum temp you might get is 55c.
As for the volume @55c that's anyone's guess. Mebbe 130 liters tops.
Then another 80 liters tailing off at a much lower temp. Further diluting the final bath temp.
If your lucky you might might end up with a final 210l bath temp of 40c.
Do you see the cunundrum here for the 10 bathers? Last person will need skin like an elephant seal or have cold water shock survival skills..

while as a professional I dont really agree with what @sirocosm is trying to achieve , but agree that if that is what he wants then who am I to say it is wrong, but your post is absolute rubbish and I really hope it is a wind up, you have absolutely no clue what you are talking about, you have obviously been in too many baths at 60c and have no skin left

 

[John D v2.0]

It's a new year, why can't people just be generous to each other.
Anyway, the op was planning to have a boiler attached which would specifically recharge it as quickly as it's being used.
If everyone argues based on things not relevant to the actual situation, then you can prove anything and never resolve any disagreement.

 

[Ryler]

It's a new year, why can't people just be generous to each other.
Anyway, the op was planning to have a boiler attached which would specifically recharge it as quickly as it's being used.
If everyone argues based on things not relevant to the actual situation, then you can prove anything and never resolve any disagreement.

I posted up a good analogy in my personal opinion.
And the bloke who classes himself as a "professional" rubbished it.
The fact is the UV will deliver more hot water than a sludge bucket thermal store any day of the week.
The reason why thermal stores are so expensive is because manufacturers know they are useless and only a few gullibles buy them so hike the price up accordingly.

 

[sirocosm]

You a professional?
You could have fooled me.

If you are a professional then how many liters of hot water will the store deliver in comparison to the UV?

My thermal store will be direct fired in that the water in the store will be heated directly by the boiler. My setup will give infinite hot water for infinite baths, as I plan to size my boiler accordingly. Try doing that with an unvented, it is limited by its (usually) small coils size no matter what size boiler you have. And good luck getting 10 baths out of a 210litre unvented, unless they look like this:

 

[sirocosm]

Thermal store advantages:

1. Buffers central heating system. You can ditch the house thermostat and go with TRVs all round. No cycling of radiator temperatures as boiler cuts in/out.
2. Potable hot water does not sit in a tank, it goes though a stainless coil. In some countries they are called "hygenic" hot water heaters for this reason.
3. Total amount of hot water depends on both tank and boiler size. Boiler can be sized up for infinite supply.
4. Eliminates boiler cycling. Allows the use of much larger, and simpler non-modulating boiler.
5. Easy to add alternate heat supplies, and alternate heat uses.

Advantages of unvented:

1. If you have a small boiler, you can get more hot water for the same size tank.
2. More common, so they are cheaper.
3. More common, so better understood by plumbers.