"Andy Hall" wrote in message
...
On Thu, 2 Sep 2004 13:43:17 +0100, "IMM" wrote:


"Andy Hall" wrote in message
.. .
On Thu, 2 Sep 2004 11:31:58 +0100, "Christian McArdle"
wrote:

Only if a conventional boiler or other heating sources are used, not
a
modulating condensing boiler.

I'd want to see further testing evidence for this, either way. I'm not
convinced which is more efficient.

Basically, does the higher temperature
burn required to reheat the heat bank
outweigh the fact that the boiler gets to
do occassional full power burns,
rather than cycling, or modulating low.

What tripe. A heat bank eliminates boiler cycling. One person ont his
thread bought one just to do that.

It depends on the type of boiler, and its thermal and control
characteristics. Grunff's application was to absorb a large amount
of heat from an oil boiler when an old coil in cylinder approach, not
surprisingly, couldn't do it.

Can't you read. The oil boiler would be cycling mainly on CH and if a lousy
cylinder on DHW too.

This is not what we are discussing
here, which was specifically the
impact of radiators hooked up to a
heatbank. If heat is being
abstracted at a lower rate than the
boiler can produce it will either
have to modulate or cycle.
If you put a heatbank in the middle, the
dampening effect screws up the condensing
boiler's control arrangement
such that it won't be able to modulate properly.

Oh my God!! Not again!!! Can't you read!!! You put on a simple cheaper
boiler (a great advantage) and allow a compensator to control the boier
which when heatinhg, heats up a large volume of water so does not cycle.

NO!!! From the cylinder...to the boiler...
called the return.

Yes, but the return is not from the radiators,
it is from the heatbank;

Which the rad circuit pumps into from its return pipe.

the storage effect of which means that the return
temperature that the boiler sees will be that of the heatbank,
together with its dampening effect as opposed to that directly from
the radiators. They are not the same thing, and a cylinder stat has
been added into the equation as well.

You clearly do not understand. A boiler with load compensation control and
an outside weather compensator controlling it. The compensator tells the
boiler that it needs the lower cylinder section heated to say 45C, it heats
it and the rads use this temperature water because the compesator said that
is the temp you need.

You can't eliminate boiler cycling with
a simple thermostat,

At least you understand that.

or even two of them.

failed again. Two stats can eliminate boiler cycling on a direct heat bank.