[OpenTRV-interest] Adaptive comfort

Tim Small tim at buttersideup.com
Tue Jul 12 16:36:41 BST 2016

On 12/07/16 15:54, Chris Skerry wrote:
> Tim,
> I wonder if I can upset the question a bit with this  —  
> My understanding of comfort for us humans depends upon 3 different external factors
> 1.  Temperature
> 2.  Humidity
> 3.  Air movement.
> Lets assume that in almost all situations the air movement is almost zero.

Careful now...  Let's assume that for British houses, in almost all
situations air movement isn't really high unless the wind is blowing

Cold surfaces in the room impacts perceived temperature, and also can
lead to "pooling" of cold air near the floor - which in turn can be also
lower the perceived temperature (cold feet!).

  If a house is draughty, then it is not that expensive to fix.  I found
installing cavity wall insulation in two houses made all the rooms more
comfortable, less temperature change at the walls, and less draughts.
> Humidity is expensive to control, as I think you would need some air-conditioning.  But it is not expensive to measure.
> I think the house owner could develop a comfort graph for the house with humidity versus temperature, so the system would measure the humidity, look at the graph and set the temperature level to suit.  The heating system would then heat to the required temperature.

I believe this work has already been done (decades ago?), and the
results published in various physiology journals although it has a much
larger effect at the high end (i.e. for air conditioning control), so
the house owner shouldn't have to do anything (beyond saying "I'm fine",
"I'm a bit cold", "I'm really cold" etc.).

Ideally the a control system would take into account external weather as
well as recent history (and perhaps even who's in the house) in order to
keep the occupants comfortable, whilst minimising energy use.

The problem is that the system would only have a simple feedback
(occupant's comfort), and would have to derive a set point from:

. Recent temperature history
. Current outdoor temperature, wind speed, and maybe solar gain and wind
direction too (and quality of building e.g. insulation, glazing type,
. Which room it's controlling
. Who's in the house
. Time of day

Difficult to get right, but I suppose it's possible, particularly given
centralised processing which can aggregate feedback and data from many


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