Hi,

Is there a online thermal store size calculator out there somewhere?
Something you can feed required energy in MJ, store max/min temps,
and it comes back with how many litres of water you need? Yeah I know
it's only simple maths but...

I've googled but failed to find anything.

--
Cheers
Dave.

Dave Liquorice wrote:

Hi,

Is there a online thermal store size calculator out there somewhere?
Something you can feed required energy in MJ, store max/min temps,
and it comes back with how many litres of water you need? Yeah I know
it's only simple maths but...

I've googled but failed to find anything.



Google for Heatweb - IIRC that brings up something along those lines..
--
Tim Watts

In article o.uk,
says...

Hi,

Is there a online thermal store size calculator out there somewhere?
Something you can feed required energy in MJ, store max/min temps,
and it comes back with how many litres of water you need? Yeah I know
it's only simple maths but...

I've googled but failed to find anything.

Is this any use
http://www.heatweb.com/
Regards
Bruce

On 19/06/2011 1:57 PM, BruceB wrote:
In whill.co.uk,
says...

Hi,

Is there a online thermal store size calculator out there somewhere?
Something you can feed required energy in MJ, store max/min temps,
and it comes back with how many litres of water you need? Yeah I know
it's only simple maths but...

I've googled but failed to find anything.

Is this any use
http://www.heatweb.com/
Regards
Bruce

That's it...

Technical Menu Flash Tools Flash main page

On Sun, 19 Jun 2011 13:57:26 +0100, BruceB wrote:

Is this any use
http://www.heatweb.com/

Ha, found that when looking for custom heat store makers(*1). This
machine doesn't have flash but will be playing with it later.

I'm thinking that I need a 1500l store(*2) which is just to damn
physically big, by a *lot*, as a cylinder (Akvaterm Solar is 1250 x
2150) to get into the room I want to use short of taking the roof off
and using a crane...

(*1) Any one know of good custom heat accumulator makers?

(*2) On the basis that the woodburner stove will chuck out a max of
8.5kW to water for up to 6hrs/day. OK the stove probably won't be
running flat out for 6hrs but as a max it's right. A 1000l(*3) store
will probably be OK (approx 6kW for 6hrs, the nominal stove output to
water), given that if the stove is on the house will most likely be
calling for heat as well so all the heat generated doesn't have to be
stored.

(*3) Still too physically big from Akvaterm at 1050 x 2100. The damn
things seem to be rather heavier than I expected as well, even before
you add 1.5 tonnes of water. I can see the floor requiring to be
strengthened...

--
Cheers
Dave.

On Sun, 19 Jun 2011 16:27:24 +0100, Vortex10 wrote:

Do you envisage the thermal store just for heating, or for year-round
DHW as well?

Ideally it is a sodding big insulated container of water to be heated
from solar panels, woodburner, oil boiler and immersion heater(s).
Outputs to CH and DHW.

Will you burn wood year-round, or perhaps use solar topped up with leccy
in the summer?

Wood will probably only be burnt evenings when it's cold so from
Oct/Nov through to Apr/May. Oil being used to make up shortfalls from
solar/wood as required, leccy being last resort back up.

For the heating will you use radiators or UFH? Or both?

Rads only. The floors are already solid. Sister has UFH, we house sat
the other year and didn't really like it, too slow to repsond to
changing weather. Up here at 1400' and exposed the weather can change
very quickly, minutes to go from bright sunshine and little wind to
howling gale with lashing rain/snow and a many degrees temp drop.

I'd be inclined towards a modest size high tech thermal store such as
the heatweb/dps Xcel at the heart of the system....and use clever
controls to divert surplus heat into a secondary lower tech but high
volume store when necessary.

The DPS stuff seems to have to much gubbins but I'll have a closer
look at the Xcel. I want the system to work as much as possible
passively. OK will needs pumps on the oil, CH and solar circuits but
I don't see what advantage there is for an external heat exchanger
and pump for DHW. The water here is soft so scale inside a coil in
the primary heat store won't be a problem.

--
Cheers
Dave.

On 19/06/2011 5:23 PM, Dave Liquorice wrote:
On Sun, 19 Jun 2011 16:27:24 +0100, Vortex10 wrote:

Do you envisage the thermal store just for heating, or for year-round
DHW as well?

Ideally it is a sodding big insulated container of water to be heated
from solar panels, woodburner, oil boiler and immersion heater(s).
Outputs to CH and DHW.

Will you burn wood year-round, or perhaps use solar topped up with leccy
in the summer?

Wood will probably only be burnt evenings when it's cold so from
Oct/Nov through to Apr/May. Oil being used to make up shortfalls from
solar/wood as required, leccy being last resort back up.

For the heating will you use radiators or UFH? Or both?

Rads only. The floors are already solid. Sister has UFH, we house sat
the other year and didn't really like it, too slow to repsond to
changing weather. Up here at 1400' and exposed the weather can change
very quickly, minutes to go from bright sunshine and little wind to
howling gale with lashing rain/snow and a many degrees temp drop.

I'd be inclined towards a modest size high tech thermal store such as
the heatweb/dps Xcel at the heart of the system....and use clever
controls to divert surplus heat into a secondary lower tech but high
volume store when necessary.

The DPS stuff seems to have to much gubbins but I'll have a closer
look at the Xcel. I want the system to work as much as possible
passively. OK will needs pumps on the oil, CH and solar circuits but
I don't see what advantage there is for an external heat exchanger
and pump for DHW. The water here is soft so scale inside a coil in
the primary heat store won't be a problem.

The primary advantages of the external heat exchanger for DHW are mains
pressure, and that you decouple water temperature from the store
temperature.

This in turn means the store can sit at 80C without scalding you when
you have a shower. of course it holds much more energy that way too.

For secondary store(s) look at the "stelstor" at bes.co.uk. Very good
value.

I have a 450 litre DPS Xcel with gas boiler, solar and immersion (all 3
are used in different circumstances) and I am pretty impressed.

Gotta go now...........

D

On Jun 19, 4:27*pm, Vortex10 wrote:
On 19/06/2011 3:07 PM, Dave Liquorice wrote:





On Sun, 19 Jun 2011 13:57:26 +0100, BruceB wrote:

Is this any use
http://www.heatweb.com/

Ha, found that when looking for custom heat store makers(*1). This
machine doesn't have flash but will be playing with it later.

I'm thinking that I need a 1500l store(*2) which is just to damn
physically big, by a *lot*, as a cylinder (Akvaterm Solar is 1250 x
2150) to get into the room I want to use short of taking the roof off
and using a crane...

(*1) Any one know of good custom heat accumulator makers?

(*2) On the basis that the woodburner stove will chuck out a max of
8.5kW to water for up to 6hrs/day. OK the stove probably won't be
running flat out for 6hrs but as a max it's right. A 1000l(*3) store
will probably be OK (approx 6kW for 6hrs, the nominal stove output to
water), given that if the stove is on the house will most likely be
calling for heat as well so all the heat generated doesn't have to be
stored.

(*3) Still too physically big from Akvaterm at 1050 x 2100. The damn
things seem to be rather heavier than I expected as well, even before
you add 1.5 tonnes of water. I can see the floor requiring to be
strengthened...

Sorry I just have questions

Do you envisage the thermal store just for heating, or for year-round
DHW as well?

Will you burn wood year-round, or perhaps use solar topped up with leccy
in the summer?

For the heating will you use radiators or UFH? *Or both?

If UFH is it in a solid floor, or a suspended one?

+++++++++++++

I'd be inclined towards a modest size high tech thermal store such as
the heatweb/dps Xcel at the heart of the system....and use clever
controls to divert surplus heat into a secondary lower tech but high
volume store when necessary.

D- Hide quoted text -

- Show quoted text -

If you do your sums you will find you are ona hiding to nothing trying
to store heat. To store signifcant heat you need a truely massive tank
and then there is the problem of keeping it in there until you need
it.
I conducted a similar exercise & came to the conclusion that the only
viable means was septic tanks full of water cast into the house
foundations.
ie thousands of gallons of water needed.
The other alternative is have truely massive house walls and store
heat in them. Ie dual function heat store. I went for this latter in
the end.

Keep the technology low. High technology tends to come unstuck due to
unforseen things. And it costs money to buy and more to maintain.
My low tech solution is simply lots of insulation around the outside
of a massively constructed house. Heat comes primarily from the TV
and fridges.

On Sun, 19 Jun 2011 17:44:27 +0100, Vortex10 wrote:

The primary advantages of the external heat exchanger for DHW are mains
pressure, ...

And why do I want mains pressure hot water? I like the water to stay
in the basin or sink when I turn ona tap not bouce out or scoot
across the curved surface and out the other side. No taps here are at
mains pressure they are all fed from the roof tanks. The only place
that might want a bar or two are showers but then I prefer a shower
of higher volume lower pressure than low volume high pressure. Low
volume just takes to long to rinse, high volume high pressure gets
painfull. The best "shower" I have ever had was several
gallons/second under direct gravity, ie a water fall. Mind you the
volume of that was borderline too much. B-)

I also like to have stored water so when the mains fails I can still
have a cup of tea and flush the bog.

... and that you decouple water temperature from the store temperature.

That is easy to solve with a mixer valve on the output of the tank.
Mixer valves are "passive" in that they don't need power to operate
unlike the pump for the external heat exchnager.

For secondary store(s) look at the "stelstor" at bes.co.uk. Very good
value.

Ta will have a look.

--
Cheers
Dave.

Dave Liquorice wrote:

On Sun, 19 Jun 2011 17:44:27 +0100, Vortex10 wrote:

The primary advantages of the external heat exchanger for DHW are mains
pressure, ...

And why do I want mains pressure hot water? I like the water to stay
in the basin or sink when I turn ona tap not bouce out or scoot
across the curved surface and out the other side. No taps here are at
mains pressure they are all fed from the roof tanks. The only place
that might want a bar or two are showers but then I prefer a shower
of higher volume lower pressure than low volume high pressure. Low
volume just takes to long to rinse, high volume high pressure gets
painfull. The best "shower" I have ever had was several
gallons/second under direct gravity, ie a water fall. Mind you the
volume of that was borderline too much. B-)

I have mains pressure hot water - but limited on a per tap basis with flow
restrictors. Which means a) no tap (or even 2 taps) can starve the system;
b) the overflow on each sink is actually able to cope with taps on full
(kids). This solves the "bounce" problem quite nicely - kitchen sink has a
medium flow, bathroom sink is about half that.

I have rather got used to being able to drink from the hot tap - or fill a
saucepan with it to get the cooking half started.

I also like to have stored water so when the mains fails I can still
have a cup of tea and flush the bog.

There is that though...

--
Tim Watts

On Sun, 19 Jun 2011 17:23:52 +0100, Dave Liquorice wrote:

On Sun, 19 Jun 2011 16:27:24 +0100, Vortex10 wrote:

Do you envisage the thermal store just for heating, or for year-round
DHW as well?

Ideally it is a sodding big insulated container of water to be heated
from solar panels, woodburner, oil boiler and immersion heater(s).
Outputs to CH and DHW.

Unless the woodburner can directly heat the rest of your house then
you'll probably want CH at the same time as your stove i srunning so,
rather than trying to store masses of heat in a thermal store, you may be
better off arranging to have the stove heat the rest of the house's rads
when it's burning.

--
John Stumbles -- http://yaph.co.uk

Extreme moderate

On 19/06/2011 11:50 PM, Dave Liquorice wrote:
On Sun, 19 Jun 2011 17:44:27 +0100, Vortex10 wrote:

The primary advantages of the external heat exchanger for DHW are mains
pressure, ...

And why do I want mains pressure hot water? I like the water to stay
in the basin or sink when I turn ona tap not bouce out or scoot
across the curved surface and out the other side.

Non-issue for us. Whole house is regulated to 2 bar. Just right.

Before the upstairs shower had a head of about 1.2 metres. When I
installed a shower pump it was the most unreliable piece of ****e we
have ever owned.

On Mon, 20 Jun 2011 07:36:16 +0100, Vortex10 wrote:

Non-issue for us. Whole house is regulated to 2 bar. Just right.

That answers my next question. B-) Bunging pressure regulating
valve in to keep things manageable, I assume they keep the pressure
on the output side at the set point up to the maximum specified flow
rate, regardless of changes in flow rate? How quickly does it
respond?

What about static pressure? Presumably that rises to mains, how
quickly does it drop to the regulated pressure when you slowly open a
tap?

Doesn't help with the no stored water problem though. I don't know
how often the mains water fails here as we have no tap on the mains.
Mains water didn't arrive until about 25 years ago before that it was
(unreliably) pumped up from a farm further down, hence three large
storeage tanks that all water goes through. They are now properly
covered and cleaned out, there was only one dead mouse and a handful
of dead centipeds together with a the odd rock and general sediment
in them when we moved in. B-)

--
Cheers
Dave.

Dave Liquorice wrote:

On Mon, 20 Jun 2011 07:36:16 +0100, Vortex10 wrote:

Non-issue for us. Whole house is regulated to 2 bar. Just right.

That answers my next question. B-) Bunging pressure regulating
valve in to keep things manageable, I assume they keep the pressure
on the output side at the set point up to the maximum specified flow
rate, regardless of changes in flow rate? How quickly does it
respond?

The one I have regulates instantly.

What about static pressure? Presumably that rises to mains, how
quickly does it drop to the regulated pressure when you slowly open a
tap?

It never rises much above the set point. I have 7.5 bar in, 4bar out. Very
little variation from flows from 0 to 50l/m

Doesn't help with the no stored water problem though. I don't know
how often the mains water fails here as we have no tap on the mains.
Mains water didn't arrive until about 25 years ago before that it was
(unreliably) pumped up from a farm further down, hence three large
storeage tanks that all water goes through. They are now properly
covered and cleaned out, there was only one dead mouse and a handful
of dead centipeds together with a the odd rock and general sediment
in them when we moved in. B-)


--
Tim Watts

On Sun, 19 Jun 2011 15:20:09 +0100, Tim Watts wrote:

(*1) Any one know of good custom heat accumulator makers?

Yes - Newark - they will take a standard cylinder size (from a list of
many possible sized)

Looks good but all cylinders. Had a quick look at the 1000l DPS Xcel
(900 x 2200) by hacking a couple of cm of plaster off both sides of
the access it would be possible to squeeze that in but the 2400
diagonal size is to big for it to rotate upright, ceiling is at
2300...

1000l with 100mm insulation all round needs a box 800 wide 2000 high
and 1100 long. That should fit through the available opening
measures opening no it fing won't the opening is only 1830 high...
So 1700 high (allows for it to be on a dolly/scaff poles to move it)
means 1300 long. Of cousre if the insulation was detachable one could
have a bigger container and insulate it when in place.

Price goes up out of propertion with diameter, but less than proportion
with height, so go for the tallest you can if you want it cheaper.

I would assume that taller helps with stratification as well?

--
Cheers
Dave.

On 19 Jun 2011 23:28:54 GMT, YAPH wrote:

Ideally it is a sodding big insulated container of water to be
heated
from solar panels, woodburner, oil boiler and immersion heater(s).
Outputs to CH and DHW.

Unless the woodburner can directly heat the rest of your house then
you'll probably want CH at the same time as your stove i srunning so,
rather than trying to store masses of heat in a thermal store, you may
be better off arranging to have the stove heat the rest of the house's
rads when it's burning.

That is effectively what will happen the water in the rads, store and
loops for the woodburner and oil boiler is the same. The size of the
room that thw wood burner will be in limits it's size to a max of
about 8kW to water (2kW to room). A rough guesstimate of the total
heating demand is about 25kW (17 rads at 1.5kW each, some are
smaller, some are larger, most are about 1.5kW) but that is to heat
everywhere mid winter. One can turn TRVs down in unused rooms to
reduce the demand. 8kW should keep main living areas tolerably warm
mid winter without burning oil.

The store is really to buffer the heat from where ever it comes from,
solar, wood, oil or leccy. The oil boiler is big, the plate says
35.2kW, but it's got a smaller jet than specfied in it. It tends to
cycle on it's stat when just heating water or the house only needs a
little heat and occasionally trips the overheat stat as well.
Stopping that cycling and tripping is also part of this.

--
Cheers
Dave.

On 20/06/2011 10:29 AM, Tim Watts wrote:
Dave Liquorice wrote:

On Mon, 20 Jun 2011 07:36:16 +0100, Vortex10 wrote:

Non-issue for us. Whole house is regulated to 2 bar. Just right.

That answers my next question. B-) Bunging pressure regulating
valve in to keep things manageable, I assume they keep the pressure
on the output side at the set point up to the maximum specified flow
rate, regardless of changes in flow rate? How quickly does it
respond?

The one I have regulates instantly.

What about static pressure? Presumably that rises to mains, how
quickly does it drop to the regulated pressure when you slowly open a
tap?

It never rises much above the set point. I have 7.5 bar in, 4bar out. Very
little variation from flows from 0 to 50l/m

Agreed.

I use the Honeywell (Screwfix 68966). works a treat.


Doesn't help with the no stored water problem though. I don't know
how often the mains water fails here as we have no tap on the mains.
Mains water didn't arrive until about 25 years ago before that it was
(unreliably) pumped up from a farm further down, hence three large
storeage tanks that all water goes through. They are now properly
covered and cleaned out, there was only one dead mouse and a handful
of dead centipeds together with a the odd rock and general sediment
in them when we moved in. B-)

On Mon, 20 Jun 2011 20:24:01 +0100, Vortex10 wrote:

Bunging pressure regulating valve in to keep things manageable, I

assume they keep the pressure on the output side at the set point
up
to the maximum specified flow rate, regardless of changes in flow

rate? How quickly does it respond?

The one I have regulates instantly.

What about static pressure? Presumably that rises to mains, how
quickly does it drop to the regulated pressure when you slowly
open a
tap?

It never rises much above the set point. I have 7.5 bar in, 4bar
out.
Very little variation from flows from 0 to 50l/m

Agreed.

I use the Honeywell (Screwfix 68966). works a treat.

Thanks chaps, all filed away for later.

--
Cheers
Dave.