[OpenTRV-interest] Adaptive comfort (and stuff)

[Marko Cosic]

Cycles per hour is a hangover from the steam boiler and non
condensing/modulating water boiler era. Modulating boilers to limit heat
input rate and flow temp comp to limit heat output rate is more current
practice.

The smaller boilers are more sensitive to mean water temp for condensing
purposes than return water temp too: less opportunity to build temperature
gradient on the HX compared with commercial scale stuff. Hence weather comp
useful.

I understand that the anti-cycling controls in modern boilers, particularly
some continental ones, do a decent job of cycling control on their own: you
set a constant call for heat and the boiler first gives the (electronic,
with feedback provided on actual flow rate achieved) pump a kick to check
for flow (open TRVs) in the heating circuit; decides no flow = no actual
call for heat and don't bother firing; waits a while depending on (a)
length of previous burn and (b) time since you last checked and/or (c) flow
temperature then tries again.

Better here than with the TRVs as Damon says imo - leave the weather comp
to 'building level' rather than room level.

We have a 7 zone Evohome setup on eBay at the moment by the way - 99p no
reserve - as we finished testing with it and nobody in the company would
have it in their own home: buggy radio, buggy gateway code, and poorly
thought through control logic being the main gripes.
On 13 Jul 2016 19:13, "Chris Skerry" <chris_skerry at icloud.com> wrote:

> Hi,
>
> My Evohome system takes account of outside temperature and requested time
> for requested temperature and starts heating early to achieve it.
>
> It also has a facility to set the number of boiler cycles per hour, if I
> remember correctly it goes from about 3 to 9.  This is to prevent excessive
> on/off cycles.  Under certain conditions when all TRVs have have closed the
> controller is still calling for heat.  So the boiler has to have a bypass.
>
> The communications system is supposed to allow the 2 x AA batteries in
> each TRV to last two years  —  I shall see.
>
> How will the DH-D system cover these matters?
>
> Regards,……….Chris.
> .
>
> On 13 Jul 2016, at 16:27, Damon Hart-Davis <dhd at exnet.com> wrote:
>
> Hi,
>
> On 13 Jul 2016, at 15:10, Simon Hobson <linux at thehobsons.co.uk> wrote:
>
> Damon Hart-Davis <dhd at exnet.com> wrote:
>
> Just a thought, for those of us where it isn't too much of a problem, is a
> hardwired connection feasible ?
>
>
> Yes, depending on details of our connector and plastics design.
>
> But I think that that is a tiny fraction of the people that we want to
> reach on this round.  We may be able to accommodate such use cases
> out-of-band, especially if the radio certfication gets too eye-watering.
>
>
> I was assuming that such cases would be more in the "hack it yourself but
> here's some ideas" kind of territory. I doubt it would make commercial
> sense as the proportion of users going that route will be a) very small and
> b) mostly techies.
>
>
> 1) We want to actively support the geek faction in all we do where
> possible, even if TRV2.0 is not primarily aimed at it.
>
> 2) We will at least try not to make it unnecessarily difficult to “hack it
> yourself”.
>
> 1) At the moment the radio is one-way.
>
>
> I didn't realise/had forgotten that
>
>
> Well, it’s on my list of things to fix but is distinctly non-trivial with
> our current ISM radios.  It maybe easier with other radios, for example,
> LoRa has a listen-after-TX mode as standard.  I’ll get Deniz to think about
> that one too, on his current researches!
>
> We have yet to decide what to include in this offering!
>
>
> I would suggest a "basic working system". I think we can all think of
> projects that floundered on the rocks of "took too long and tried to add
> too many bells and whistles". Pack of heads plus a relay unit, pre-paired
> (optional while you're selling to techies, essential after that), and
> software with the features you've described.
> Being able to read the data from the system out-of-the-box would be nice -
> that way us techies who are likely to he the majority of early adopters can
> start making pretty graphs that our other halves can go "yes dear, very
> nice" to in that special "I really don't care" tone of voice they have !
>
>
> You are absolutely preaching to the converted.  MVP, avoiding
> feature-itis, etc, is the ONLY way we’re going to get this done at all!
>
> Rgds
>
> Damon
>
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