Re: Real HA - central heating control by the radiator

[Lehane Kellett <lehane@xxxxxxxxxxxxxxxxxxx>]

ian.bird@xxxxxxx wrote:
> Hi David
>
> I was thinking about this and I liked Kevin's suggestion of just
switchin=
g
> the 10v feed on or off giving me effectively the same as the on off
unit.
> As you say though this opens up potential for future expansion.
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The 10V units are significantly more expensive than on/off and much more=20
difficult to get hold of, even
the 24V in the UK seem to be disappearing. Oventrop are one company to try.

I have my doubts, for a domestic install anyway, whether full=20
proportional on a single rad is worth the
=A340-50 quid a go extra. For DHW mixing, definitely.
> >From my point of view I have to build something that will work by
next
> winter which is not a whole lot of time away taking into account
having t=
o
> go to work too.
>
> My initial thoughts are:
> 1) Local power supply to power the unit and the valve (no idea how
much 2=
4
> volt supplies are?). May go with POE and a 24volt network so 2 times
Cat5
> to each zone.
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Excellent 24V 10A supplies are around - check ebay. Siemens, Lambda,=20
Invensys, etc. All DIN rail
mount for industrial logic controller use.

I'd go with a central control and drop 4 core to the rads. Only one good=20
PSU needed then.
> 2) Ethernet connected local units to switch the valve. Will also take
a
> minimum of two temperature readings. One would be for the room
temperatur=
e
> in the chosen location and the other would be the radiator
temperature. I=
n
> reality there would probably be the ability to have more room temp
units.
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I don't think the rad temperature is worth the effort - if you know how=20
long ago you switched
it off and the current room and outside temperatures that's going to be=20
enough - unless you
start tracking doors opening and people movement too! Each room will=20
have a different
cooling/heating slope.
> 3) Mark 1 units would only switch on and off
> 4) Communication protocol is open but I would think xAP would be a
good
> choice. This would also fit in with some graphic displays I am
designing.
> 5) Initially I would probably use HomeVision to control the radiators
(it
> does the heating now) but I would aim to add additional brains in a
home
> made control unit. Ultimately I would not only want radiator by
radiator
> control but also control from every room in the house with
customisable
> abilities. For example the kids rooms would only be able to control
that
> room whereas the main bedroom would not have any limits. I plan
password
> protection on these too so no kids sneaking into mum and dads room for
> dastardly deeds ;-).There would also need to be a master control so
the
> kids don't just set it on all the time. Lots of permutations to
confuse m=
e
> horribly. Of course it would be nice to record what was on when and
where
> it was activated from which I would include in my home made control
unit.
> This could then be queried from a PC and printed or whatever.
>
> Boiler cycling would be controlled in software somehow. Long way away
fro=
m
> that though.
>
> The beauty of this approach is I can phase the system in as time
allows a=
nd
> debug on route. I would also try and make the Ethernet part of the
unit
> separate from the switching part as this will keep costs down when I
chan=
ge
> the spec. Just have a plug and socket type of connector. Also, since
size
> is not a big issue I can design for 'PCB comfort' rather than for the
> smallest size as I have been doing of late. Roll on that PCB
autorouter ;=
-)
>
> I would guess 8 units would be my ideal. This would give me one spare
and
> leave one Radiator without a valve so heat can always be dissipated in
th=
e
> case of something going wrong.
>
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With a new build I've had the luxury of bringing all the upstairs=20
rads(9) back to two manifolds
and the actuators are on those (Danfoss). JG UFH with 24V actuators=20
downstairs.
They are controlled by an 2 xAP Netiom and DIN relays- not sure I'd go=20
to the effort of a PCB.

Lehane

> Ian
>
>
>
>
>
>
>                                                                       
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>                       "David Gumbrell"                      
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>                       <david.gumbrell@g        To:      
ukha_d@yahoogrou=
ps.com                                                      =
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>                       mail.com>                cc:       (bcc: Ian
Bird/C=
V/Novartis)                                                 =
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>                       Sent by:                 Subject:  Re: [ukha_d]
Rea=
l HA - central heating control by the radiator              =
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>                       ukha_d@yahoogroup                               
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>                       s.com                                           
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>                       28/03/2006 01:47                                
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>                       ukha_d                                          
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>
> Hi Kevin,
>
> If you go for a bulk buy, I'd be interested in 6-7 of the proportional
> ones.
>
> Ian: I think proportional will give you much greater scope for decent
> control schemes, although at a cost, obviously. I suspect On/Off is
> going to create more boiler cycling.
>
> Cheers,
>
> Dave
>
> On 3/27/06, Kevin Hawkins <lists@xxxxxxx> wrote:
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>> ian.bird@xxxxxxx wrote:
>>=20=20=20=20=20
>>> Hi Kevin
>>>
>>> Where did you get the price from? Also any idea how much the
other
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> parts
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>>> needed are? I will need 7 at the end of the day plus maybe a
spare
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> head.
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>> That was just a Google using the part number - it pulled up a PDF
>>=20=20=20=20=20
> pricelist
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>> Danfoss Gesmbh Presiliste April 2005 Warmetechnik  www.danfoss.at
>>=20=20=20=20=20
>>> A 0 to 10 volt control voltage doesn't sound too hard although
for home
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> use
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>>> I suspect the on/off ones would be just fine.
>>>
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>> I'd prefer the proportional ones I think - at worst case I can
just
>> drive them with ONOFF 10V I guess if that all goes pear shaped.
>>
>> Kevin
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> Yahoo! Groups Links
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