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Thread: HA CH controls - where do I start?!

  1. #1
    Automated Home Jr Member Simon300's Avatar
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    Question HA CH controls - where do I start?!

    I'm specifying a gas/solar central heating system. It is an old house so, although the wall insulation will be improved, I will still have radiators and probably two wet UFH (bathrooms) zones. The house is sometimes partially occupied so I am keen to build in intelligent controls, so that for example, a home office could be heated on its own during the day.

    I found those Sauter 24V TRV head replacements. As part of the renovation the house could be re-plumbed to have two or three zones and those valves on some of the rads.

    What I've found most domestic CH controls aren't really geared up to many zone programming. Then I stumbled into HA...

    The only HA-like stuff I have now is a LinkStation Pro LS-XHL NAS which has been "opened" to run NFS and SqueezeCenter. It's quick (1.2GHz I think) and fairly low power (~10W when idle) and could easily run another webserver.

    I can see there are a number of competing products but have been getting swamped! Idratek seemed an interesting starting point but I don't want anything that needs a Windows PC running 24/7. Clipsal seems to have quite a large following and active forums.

    I suppose what would be ideal would be:
    • a unit that I could wire the rad/zone valves and boiler to (which probably will be OpenTherm compatible), and that had an ethernet connection,
    • a 1-wire system controller, again ethernet connected (which I've seen), that has thermometers in each/key rooms,
    • some (Linux) software that ran all the time on the LinkStation and could control components.


    Then I could just use a browser, e.g. on a hacked O2 Joggler, to interact with the heating.

    Of course once the HA infrastructure were there I might like to do more later, but at the moment the purpose is just to create a more efficient heating system.

    My observations so far:
    • I like the idea of the pink C-Bus CAT5 cable so that you can run signal and mains cables in the same conduit
    • Both Idranet and C-Bus are distributed systems than can run without a central controller (though with what intelligence - possibly not enough for CH control without having quite intelligent room thermostats?)
    • Both Idranet and C-Bus can be wired in topologies of star, daisy chain, or a combination of both.


    Therefore my initial thoughts are:
    • run a single 1mm T+E from each rad to a central point (to use for 24V)
    • have 24V rad valves & single power supply at the central point. The control system would use relays to switch the 24V, though would also need to switch 240V for zone valves
    • run a pink C-Bus cable from room to room (at the rad or light switch?)


    My main priority is to choose something now that would then be compatible with other HA stuff later (which rules out some of the heating only products like HouseHeat I think).

    Sorry for the very long post! Any thoughts or comments would be very welcome :-)

    Simon

  2. #2
    Moderator toscal's Avatar
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    Take a look at the Idratek stuff. www.idratek.com And they have their own forum on here.
    You could also look at the House Heat System, there has been quite a lot of forum activity on this http://www.automatedhome.co.uk/vbull...ght=House+Heat.
    Actually the only difference between normal CAT5 and the CBUS stuff is that the insulation on the CBUS cable is mains rated.
    This is from the CBUS install manual
    "Care must be taken to adequately segregate the 240 V AC wiring from the C-Bus wiring........The Mains rated pink insulation will allow the C-Bus Cat-5 cable to be run closer to mains wiring than would be allowed under normal circumstances. It is still good practice to keep them as far apart as possible and cross at 90 degrees to give the greatest margin of noise immunity both within the confines of the switchboard and around the installation."
    Last edited by toscal; 14th May 2010 at 11:07 PM.
    IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.
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  3. #3
    Automated Home Legend Karam's Avatar
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    Quote Originally Posted by Simon300 View Post
    I can see there are a number of competing products but have been getting swamped! Idratek seemed an interesting starting point but I don't want anything that needs a Windows PC running 24/7. Simon
    I should say at the outset that I am an IDRATEK person so you might want to read my post with a pinch of salt, though I hope that its more explanatory than biased

    If you want to just do basic zoned heating then a structure not requiring a PC is probably sufficient. But if you want to go any further with the sophistication of the heating control, or to implement other home automation features, then something with the grunt and feature set of a PC becomes compelling. That its running MS Windows in the IDRATEK case is maybe initially construed by some as a necessary evil but in reality is no more a liability than other higher powered computing platforms if administered sensibly. Also, Small form factor low power consumption hardware is becoming increasingly available these days.

    What is probably more important to consider is how far you want to take the automation as to whether its 'worth that evil' . Considering the heating control aspect alone for example: Whereas the IDRATEK system is at the very least comparable to other advanced solutions in providing full 24/7 setpoint profiles for each zone and methods for compensating against variations in external conditions, the much more important and markedly different aspect of the system is its ability to deduce and make use of occupancy information to automatically adjust heating setpoints in a realistic way. This is where significant savings are to be gained. There are also numerous other features which make good use of the integrated environment such as the ability to access any heating zone controls at any user interface location, and the ability to do intelligent 'heat dumping' to name but a few.

    If you extend the remit to lighting control then the same infrastructure for occupancy detection can be used to automate the lighting. And very likely that some spare functionality on existing hardware can also be utilised.

    Security? Again some of the infrastructure is already in place though you may wish to add cameras and specialised sensors and annunciators.

    And so on... - you get the idea hopefully that as you progress your automation system an integrated structure becomes ever more cost effective and useful. An integrated structure also means much less programming effort trying to patch together different sub systems and trying to implement complex logic. So hopefully it becomes easier to understand why you need something like a PC to co-ordinate all of this functionality. The PC also offers a convenient physical component for remotely accessing the system and for diagnostics, data archiving and analysis features.

    I note that the IDRATEK system is often compared with the likes of C-Bus or KNX, perhaps because of the perceived similarity of the physical infra-structures, but actually it is a very different beast once you go beyond basic control (Reflex level) functions.

  4. #4
    Automated Home Jr Member Simon300's Avatar
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    Quote Originally Posted by Karam View Post
    If you want to just do basic zoned heating then a structure not requiring a PC is probably sufficient. But if you want to go any further with the sophistication of the heating control, or to implement other home automation features, then something with the grunt and feature set of a PC becomes compelling. That its running MS Windows in the IDRATEK case is maybe initially construed by some as a necessary evil but in reality is no more a liability than other higher powered computing platforms if administered sensibly. Also, Small form factor low power consumption hardware is becoming increasingly available these days.
    ...
    Thanks for the detailed reply Karam. Certainly Idratek seems to have a good following and looks keenly priced. I also like the idea of being able to fall back to the Reflex controls if all the central stuff fails.

    Unfortunately having a Windows PC is definitely out for me (in fact Ubuntu is pretty much the only OS we're using at home now). I see Idratek publishes the API so I suppose you could implement something basic, e.g. in Perl.

    I do quite like the look of some kind of combination of xAP and 1-wire - I've got an O2 Joggler (Atom/Linux based) on order which might be able to serve as both a control unit and panel, although this would possibly be even more home grown

    Starting with running T+E back from the rads to a central point seems a fairly uncontroversial first step though.

    Thanks again for your input Karam, and thanks too to toscal for pointing out restrictions for the pink CBUS cable.

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