On Mon, 6 Sep 2004 00:14:08 +0100, "IMM" wrote:


"Andy Hall" wrote in message


If you segment the heatbank into two and deliberately run the lower
half at a lower operating temperature, you are cutting into the
storage for the DHW application. This implies either a larger or a
separate heatbank to do the job.

A taller heat bank that's all.

In order to achieve your solution, we are at a 300 litre minimum
heatbank.

From somebody who normally makes such a huge issue about airing
cupboard space as a justification for combis, this is hilarious.


This is why it is far better to treat the CH and the DHW as the two
totally different systems that they are in terms of thermal
characteristics and time constants and to simply drive the radiators
from the modulating boiler.

Not cheap to do this.

Of course it is. You simply need a system boiler and a diverter
valve.

When the boiler gets a signal from the DHW, it can wind up to full
power for the short suration required.

During CH operation, it will modulate down to the heat requirement
directly required by the radiators. A simple, efficient and
effective solution.



and the boiler will cycle anyway.

For a corner case around the lower modulting limit of the boiler.
Would you like mw to do the sums for you to show that this is a
non-issue.

Better ways of
doing it.

Not with a heatbank when a condensing boiler is the sole source of
energy.




This is the intent of the manufacturer's
design

The boiler manufacturers design you mean.

Of course. In the absence of a sophisticated external controller
with full instrumentation and analogue control of the boiler, having
the intelligence in the boiler is the obvious and correct place.


and without a more sophisticated set of sensors and controller
than is inside the boiler, and a boiler that can be analogue
controlled, if the gas boiler is the only source of energy, you won't
improve on it.

What tripe. Stop making things up.

Go and do some reading on control systems and condensing boiler
technology - none of these are complicated concepts for most people.


..andy

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