[wxqc] Opinions please -- New design for solar radiation shielding

[Victor Engel]

So the thermometer is INSIDE the tube?

On 5/4/07, Bryce Alexander <bryce at azlab.net> wrote:
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> After reading all the material that the CWOP program references about solar
> radiation shields I had a brainstorm for a different design.
>
>  In essence it is a six inch pipe, open at either end, with the pipe set at
> an angle such that it is oriented on a North/South plane with the north end
> higher than the south end. Both ends of the pipe are cut at angles so that
> no sun is able to enter the bottom half of the pipe regardless of the
> seasonal angle of the sun's ecliptic. I used nylon screws to mount the
> instruments to the inside of the pipe to prevent heat transmission from the
> outside of the pipe through the screws.
>
>  Take a look at the Flickr images on
> http://weather.gladstonefamily.net/site/C7166  to see how
> my prototype is constructed and to make sense of the above description.
>
>  The thinking is, that because the north end of the pipe is elevated we will
> get a chimney effect of the warmer air rising upward at the North end and
> the cooler air "falling" out the south end of the pipe. The theory is that
> there is very little chance of air stagnating in this configuration.
>
>  One thing I noticed right away is that the temperature and humidity seems
> much more dynamic (or in other words, more changes during a given time
> frame) which seems to indicate that I am indeed reducing the incidence of
> air stagnation I was seeing with a gill style solar shield.
>
>  The one down side I see right now is that a driving rain from the North
> might get the instrument package wet. I will have to create some kind of
> barrier or hood that will not interfere with the convective flow. The nice
> thing is that I believe this can remain passive (not fan aspirated) even
> during the worst of the Arizona heat, we will see this summer.  I do notice
> some slightly higher temps during the day, but they are not the same thing I
> was seeing when I had a solar radiation problem. I would attribute that to
> the microclimate of being between Stucco houses, with cinder block fences
> and tile roof in proximity to the sensor.
>
>  If anyone wants to go back into my historical data I added the shield on
> April 21 and tweaked my humidity about four days ago.
>
>  Let me know what you think, I welcome any suggestions or comments, positive
> or negative.
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>
> Feel free to use this design for hobby or research purposes with proper
> attribution, anything else by permission.
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