[OpenTRV-interest] Adaptive comfort

Wed Jul 13 12:56:29 BST 2016

I'd love to sample a controllable TRV.  I have a number of RasPi doing
rather little at the moment.

On 13 July 2016 at 12:54, Damon Hart-Davis <dhd at exnet.com> wrote:

> Hi,
>
> This may be the moment to whisper quietly that we are working up to a
> small reward/product crowdfunding campaign in the autumn to be able to put
> kit into consumer hands.
>
> Lots of detail to be sorted yet, but if people would indicate here (or to
> Victor [victor at opentrv dot uk] directly) if they’d like to be notified
> in the run-up to the campaign, that would be handy.
>
> Rgds
>
> Damon
>
>
> > On 13 Jul 2016, at 12:37, Lisa Ann Pasquale <
> lisa.pasquale at six-cylinder.co.uk> wrote:
> >
> > I'm developing a heating controller from a RasberryPi, which I expect to
> cost ~£150, including sensors, and most hardware (using off-the-shelf
> components). I was hoping to use Open-TRV for zone control, which is why
> I'm on this forum.
> >
> > As mentioned, though, I wouldn't link the RH sensor to the heating. The
> RH would link it to the ventilation (MEV, in my case) through humidistats,
> which is a separate system to the TRVs and heating. Whilst linked to
> thermal comfort, it's far more efficient and effective to control
> ventilation off RH data, not heating.
> >
> > Lisa
> >
> > On 13 July 2016 at 12:28, Chris Skerry <chris_skerry at icloud.com> wrote:
> > So between us we have invented a new system. . . . . .
> >
> > 1.  Everything WiFi linked to the cloud
> > 2.  One central TRV that measures humidity as well as temperature.
> > 3.  A sophisticated control system in the cloud.
> > 4.  A simple App that sends and receives from the cloud’s control
> programme.
> >
> > The controller would learn the characteristic of the house, the outside
> conditions (temperature, wind & humidity) from the internet, and the
> people’s demands for heat or less heat, and their time schedules.
> >
> > It would be constantly adjust to the minimum energy consumption related
> to the number of user tweaks up or down.
> >
> > Eventually the control program would have learned every thing it needs
> to know.  But, if the user is someone who is constantly wanting more or
> less, he/she can have it with say +2 degrees or -2 degrees for 2 hours.
> >
> > So it would not matter about the users lack of knowledge.  The system
> would adapt to user demands.  I have a relative who keeps her house at 23
> degrees during the winter daytime, much too hot for me.  Others will wear
> thick jumpers and accept 18 degrees or less.
> >
> > I would expect it to be half the price of the Evohome system.
> >
> > So when will we get it?  Who will design and build it?
> >
> > Regards,…………..Chris.
> > .
> > > On 13 Jul 2016, at 11:19, Simon Hobson <linux at thehobsons.co.uk> wrote:
> > >
> > > Lisa Ann Pasquale <lisa.pasquale at six-cylinder.co.uk> wrote:
> > >
> > >> Humidity is a metric which is more relevant for controlling
> ventilation than heating.
> > >
> > > It still has relevance to maintaining "comfort".
> > >
> > >> When the humidity rises, you need to ventilate to remove the
> moisture. Increasing the temperature only disperses it and adjusts the
> dewpoint - it doesn't remove the moisture, which is a risk of condensation
> and mould problems within the home - regardless of comfort. Tweaking the
> temperature is unlikely to alleviate discomfort caused by high or low
> humidity levels as efficiently or effectively as ventilation.
> > >
> > > Mostly true. But humidity does have a part to play in perceived
> comfort - or at least perceived "is the temperature OK". From my own
> observations ...
> > > As a very crude generalisation, high humidity gives a perception of
> higher temperature, and low humidity gives a perception of low temperature
> - with a fairly wide band of humidity in the middle where the effect is
> minimal. It's very non-linear.
> > > Thus someone (but not me !) may feel quite comfortable with
> temperatures in the high 20s when humidity is low, but feel "stiflingly
> hot" in the mid 20s with high humidity. I suspect some of that isn't so
> much whether our body is too hot or not, but the discomfort of feeling
> "clammy" from the sweat that isn't evaporating quickly when the humidity is
> high.
> > >
> > > Of course, air movement affects this. If the air is moving, it clears
> away that boundary layer of moist air and allows more sweat to evaporate -
> hence a fan making us feel cooler even though it might have zero effect on
> actual temperature.
> > >
> > > Quite complicated ! And probably far more complicated than is
> justified - or even productive.
> > >
> > >
> > >
> > >
> > > Damon Hart-Davis <dhd at exnet.com> wrote:
> > >
> > >> Note that the rather nice humidity and temperature sensor that we use
> (SHT21) is more expensive than and larger than and has tougher power supply
> requirements the temperature-only device that we otherwise use (TMP112).
> There is a significant cost implication of using RH (maybe even a fiver at
> retail) so it needs to pay its way.
> > >
> > > Which is a very important point. Unless the devices are wired to a
> power supply, more power == shorter battery life == more cost and
> inconvenience for the end user. Any benefit needs to be enough to outweigh
> that cost - and personally I very much doubt that it would in most cases.
> > > Bear in mind that a very large proportion of people (again, from
> observation) don't grasp the concept of a thermostat. And at the risk of
> coming across as sexist, my observation is that women are the worst
> offenders in this. My observations come from having responsibility for
> office heating and cooling for some years at my last job - and the constant
> resetting of controls on AC systems.
> > > The cycle would typically go like this ...
> > > I'd reset the system, on it's timer, with a "reasonable" setpoint -
> and explain how the setpoint can be turned up or down by a degree or two.
> Bear in mind that some of these users would come to work in midwinter
> wearing a light summer outfit and be most offended at the suggestion that
> if they know they are likely to be cold at work, they may wish to reassess
> what they wear ! This brings up another factor in perceived comfort - if
> they are coming into the office cold from the commute, then they need the
> office a bit warmer than if they arrive warm.
> > > So first thing in the morning, someone would turn the controls up to
> max (30˚C) rather than just turning it up a degree or two. Needless to say,
> with a 14kW AC unit blasting away in a not too big office, it's soon "quite
> warm" and the unit just gets turned off.
> > > Then in the afternoon, things are still getting warmer - so the AC
> gets turned on and turned down to min (18˚C). 14kW of cooling soon gets
> things chilled down, so it gets turned off again.
> > > Then next morning, the heating hasn't been on - and somehow it's *MY*
> fault that the office is cold :-/
> > >
> > > So once again I reset the system, and explain YET AGAIN that this
> thing has temperature control and the trick is to just nudge it up or down
> a degree or two as needed. That might work for a day or two, then the cycle
> repeats, and once again it's MY fault that they can't use the system.
> > >
> > > Eventually, as the offices were expanded, we went with hidden units,
> with networked controls (which I had modified to work around some of the
> control issues) so there was nothing for users to fiddle with. I'd still
> get the occasional "can you turn it up/down a bit ?" requests, but once
> they weren't able to fiddle with the controls, most users learned to live
> with it.
> > >
> > >
> > > So when designing a system, the sort of people discussing it here on
> this list aren't the ones you need to think about. There's that joke about
> it being hard to make things foolproof because fools are so ingenious - but
> there's a grain of truth in that. As above, the majority of people who
> these things are aimed at will be the type that struggle with the concept
> of "if you are a little cool then turn the heat up a little", the sort of
> person where the wall thermostat is either on max or min and is used as a
> switch (ie the heating is either "on" or "off").
> > >
> > >
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> >
> >
> > --
> > Lisa Ann Pasquale  BArch MSc CEng MCIBSE
> > Director | CoRE Retrofit Coordinator | CoRE Fellow
> >
> > *UK Green Building Council Rising Star 2016*
> >
> > +44 7896 051 660
> > http://six-cylinder.co.uk
> >
> >
> >
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