Re: RE: multi-zone central heating

[Ake Hedman <akhe@xxxxxxxxxxxxx>]

I second that Kevin.

/Ake

Kevin Hawkins wrote:

> christopher purves wrote:
>
> >Hi All,
> >
> >I'm now getting a little confused by some of the replies on
this=20
> topc. As
> >far as I am aware, SK use the HoneyWell Proportional Actuators
with=20
> the LON
> >network (look very similar if they don't :))  room temp sensors
and=20=20
> some
> >smarts (along with an external sensor or two). I'm sure SK
spent=20
> quite some
> >time developing algorithms and control interfaces and so on and
ao=20
> forth and
> >thus I am happy they can justify their price (especially when when
you
> >include the design/installation consultancy part).
> >
> >Some people **seem** to be suggesting that this sort of system
will not
> >work.
> >
> >Do I understand correctly ?
> >=20
> >
>
> Whooa...I am not in any way going to be draw into saying someones
> product can't work - particularly as I am not in an informed position
to
> comment as I haven't tried them plus I made my comments on  input.
from
> others ie 'heresay'...
>
> The comment was made in relation  to my idea of the remote room
> thermostat being used in a feedback system to control the proportional
> valve.  I have an (offlist) reply from an individual in the industry
who
> is suggesting this will not be workable. He says using proportional
will
> provide no benefit cf On/Off really. His reasons are that thermal
> inertia and time lag would make the process parameters unsuitable for
> implementing a suitable feedback/control system.My take on this is he
> means that the time from applying heat to the radiator and the
> thermostat registering the benefit and being able to modulate the flow
> are just too long with too much inertia - and I can see that is likely
> as it must have a reaction time of several minutes.  Now I have no
> comment at all on how SK achieve this and how effective it is.  Their
> modelling might be sufficiently sophisticated and they might base this
> on different feedback mechanisms eg radiator temperature, outside
temp,=20
> flow temperature,  or room temp sensors actually in their actuators
> which I guess would produce a tighter feedback system.  Plus they
> obviously use knowledge of the particular room dynamics. So I am sure
it
> works  a lot better than my current system does.   Both Ake and myself
> are I think saying that we are being 'told' that achieving stable
room=20
> temperatures, (ie not oscillating),  from these sort of systems in
a=20
> residential environmenmt is quite a difficult thing to do,
particulalry
> as flow temps vary with a modulating boiler. Neither of us quite want
to
> believe that but maybe it's true.
>
>    Kevin
>
> >
> >
> >Chris
> >
> >=20
> >
>
>
>
>
>
> *Yahoo! Groups Sponsor*
> ADVERTISEMENT
> click here=20
> <http://us.ard.yahoo.com/SIG=3D129no3r1p/M=3D283686.4531047.5839501.44200=
29/D=3Dgroups/S=3D1705041992:HM/EXP=3D1106411918/A=3D2044486/R=3D0/SIG=3D10=
svm8ftb/*http://www.theironshop.com>=20
>
>
>
>
------------------------------------------------------------------------
> *Yahoo! Groups Links*
>
>     * To visit your group on the web, go to:
>       http://groups.yahoo.com/group/ukha_d/
>=20=20=20=20=20=20=20=20
>     * To unsubscribe from this group, send an email to:
>       ukha_d-unsubscribe@xxxxxxx
>       <mailto:ukha_d-unsubscribe@xxxxxxx?subject=3DUnsubscribe>
>=20=20=20=20=20=20=20=20
>     * Your use of Yahoo! Groups is subject to the Yahoo! Terms of
>       Service <http://docs.yahoo.com/info/terms/>.
>
>


--=20
---
Ake Hedman (YAP - Yet Another Programmer)
eurosource, Brattbergav=E4gen 17, 820 50 LOS, Sweden
Phone: (46) 657 413430 Cellular: (46) 73 84 84 102
Company home: http://www.eurosource.se=20=20=20=20=20=20
Kryddor/Te/Kaffe: http://www.brattberg.com
Personal homepage: http://www.eurosource.se/akhe
Automated home: http://www.vscp.org



[Non-text portions of this message have been removed]