RE: Outside/Inside Temperature Sensor location

["Neil Wrightson" <neilw@xxxxxxxxxx>]

Thanks Neil,

More good feedback.


Regards,

Neil Wrightson.



_____

From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx] On Behalf Of
Neil Ball
Sent: Saturday, 31 January 2009 7:58 AM
To: ukha_d@xxxxxxx
Subject: RE: [ukha_d] Outside/Inside Temperature Sensor location



Internal room temperature gradients depend on the kind of heating you use -
radiators are usually run at high temperatures so create strong convection
currents forcing warm air towards the ceiling, underfloor heating is
relatively low temperature so much less convection meaning air can actually
be significantly cooler at high levels. A good rule of thumb for most rooms
is to pick a spot unaffected by external influences (sun through a window,
not directly above heat sources etc) and go for light switch height (which
can be anywhere between 3-5 ft in most houses).

Outside look for a north-facing wall (therefore unaffected by direct sun)
and either use a purpose designed external sensor or find a suitable
housing.

Your sensor will not measure radiant temperature so if you do have a
radiant
source at much higher/lower temperature than the air then it will affect
physical comfort without being registered by the room sensor but it is
easier to use a manual approach to dealing with this than trying to get too
clever with any automation and lots of black bulb sensors will have pretty
low WAF factor!

Neil B.

_____

From: ukha_d@yahoogroups. <mailto:ukha_d%40yahoogroups.com>
com
[mailto:ukha_d@yahoogroups. <mailto:ukha_d%40yahoogroups.com>
com] On Behalf
Of
Neil Wrightson
Sent: 30 January 2009 20:09
To: ukha_d@yahoogroups. <mailto:ukha_d%40yahoogroups.com>
com
Subject: [ukha_d] Outside/Inside Temperature Sensor location

Hi,

I'm looking at putting some 1wire/ibutton temperature sensors in and I'm
wondering where is the best location for the sensors.

Outside

Just mounting on the side of the house or garage wall would not do due to
the possible heating or cooling effect of the brickwork.

Even putting it a short distance i.e.300mm of the brick work. It would
still
be affected by radiated heat.

Putting it in the middle of the yard where there is no shade sounds ok but
then how? Sky hook? And it also would then be affected by the direct
radiated heat from the sun, making it feel hotter than it actually is.

Inside

Same problem with inside, picking up the ambient room temperature without
being affected by the internal wall temperatures, sometimes the actual
walls
can be substantially cooler/hotter than the air temp. Also what height,
again there can be quite a few degree's C difference between the
temperature
300mm of the floor to 300mm of the ceiling.

Where is the ambient temperature?

Regards,

Neil Wrightson.

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