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DS1620 in the shade

Z

zliminator

Jan 1, 1970
0
I'm using several DS1620 digital temperature sensor chips in my home energy
management system. I've got one reading the return air temp, one for the
supply and two to measure the outdoor temp. The two outdoors are going to be
hanging under the eves on the east and west side. I basically want to get an
idea of the actual heat loss by measuring and comparing indoor and outdoor
temp at several points. (Block/stucco 1925 central FL) I'm also monitoring
how much the a/c runs. I'm wondering if I should put it low enough to be
exposed to sunlight and/or next to the side of the house or should it be in
the shade. I suppose if its next to the side of the house, it will measure
more of the block heating up as a result of being exposed to the sunlight.
If its in the shade, then it probably won't make much of a difference
because the chip is not that big. If it too close to the top of the brick
under the eves, it will pick up too much hot air drifting up off the walls.
Any suggestions from experience before I start testing? I will try and put
some more info on my website and post the address later.

Dan
 
J

Jim Thompson

Jan 1, 1970
0
I'm using several DS1620 digital temperature sensor chips in my home energy
management system. I've got one reading the return air temp, one for the
supply and two to measure the outdoor temp. The two outdoors are going to be
hanging under the eves on the east and west side. I basically want to get an
idea of the actual heat loss by measuring and comparing indoor and outdoor
temp at several points. (Block/stucco 1925 central FL) I'm also monitoring
how much the a/c runs. I'm wondering if I should put it low enough to be
exposed to sunlight and/or next to the side of the house or should it be in
the shade. I suppose if its next to the side of the house, it will measure
more of the block heating up as a result of being exposed to the sunlight.
If its in the shade, then it probably won't make much of a difference
because the chip is not that big. If it too close to the top of the brick
under the eves, it will pick up too much hot air drifting up off the walls.
Any suggestions from experience before I start testing? I will try and put
some more info on my website and post the address later.

Dan

For my outdoor sensor I ran a lead out to an orange tree and hid the
sensor in the foliage ;-)

...Jim Thompson
 
M

Michael

Jan 1, 1970
0
zliminator said:
I'm using several DS1620 digital temperature sensor chips in my home energy
management system. I've got one reading the return air temp, one for the
supply and two to measure the outdoor temp. The two outdoors are going to be
hanging under the eves on the east and west side. I basically want to get an
idea of the actual heat loss by measuring and comparing indoor and outdoor
temp at several points. (Block/stucco 1925 central FL) I'm also monitoring
how much the a/c runs. I'm wondering if I should put it low enough to be
exposed to sunlight and/or next to the side of the house or should it be in
the shade. I suppose if its next to the side of the house, it will measure
more of the block heating up as a result of being exposed to the sunlight.
If its in the shade, then it probably won't make much of a difference
because the chip is not that big. If it too close to the top of the brick
under the eves, it will pick up too much hot air drifting up off the walls.
Any suggestions from experience before I start testing? I will try and put
some more info on my website and post the address later.

Dan

You definitely *do*not* want the sun to strike your sensors. My
indoor/outdoor thermo's outdoor sensor (DS1820) used to sit in a window,
between screen/storm window and sash. Bad news. Even when the screen
was down (not the storm window) the window area was a hot house that
resulted in wild reading. I stepped out in shirt sleeves one sunny
spring day because the thermo said 70's; turned right around and went
back in for a jacket!

You don't want an outdoor sensor close to your house either, for the
same reason, i.e. the heat radiating from it will fool the sensor. I
moved my outdoor sensor to beneath an awning over the front door and
though the front of the house faces south, it's a better spot for a temp
sensor than a window. I made a PIC gizmo that logs temp & time/date
every 5 minutes, 24/7. When I look at a plot of the data I can tell
when the sun moves to the front of the house (temp spikes) and also see
the bried period when the tree out front shades the awning where the
sensor is located (temp dips briefly).

I'd like to move the sensor out behind the garage (north-facing) but
that would make the 2- or 3-wire run way too long and cumbersome ....
something like sixty feet.
 
D

Dan

Jan 1, 1970
0
Maybe I'll put 2 close to each other, one in the sun and one in the shade.
That way I'll
get an idea of how much radiant heat to expect. I'm using a controller card
with 40 io
pins and all sensors share the same RST and CLK and the send data command
gets
sent in parallel to all the other DQ lines, so I plan on having around 10 or
so sensors
for both the house and apartment in back. That way I can graph them all to
see trends
to determine the heat loss. I'm hoping for some more warm days so I can do
analysis
before and after putting insulation in. That's a question for
alt.building.construction.

As far as signal loss, I was wondering if it would help long stretches to
have a remote 5vdc
supply for each long run but still share a common gnd. Either that or
increase the time delay
between pulses. I'm going maybe 30' at most and so far I've been lucky. I
wish I could have
had it working the other day during the solar flares. That would have been a
good test - aye?

Dan
 
M

Michael

Jan 1, 1970
0
Dan said:
Maybe I'll put 2 close to each other, one in the sun and one in the shade.
That way I'll
get an idea of how much radiant heat to expect. I'm using a controller card
with 40 io
pins and all sensors share the same RST and CLK and the send data command
gets
sent in parallel to all the other DQ lines, so I plan on having around 10 or
so sensors
for both the house and apartment in back. That way I can graph them all to
see trends
to determine the heat loss. I'm hoping for some more warm days so I can do
analysis
before and after putting insulation in. That's a question for
alt.building.construction.

As far as signal loss, I was wondering if it would help long stretches to
have a remote 5vdc
supply for each long run but still share a common gnd. Either that or
increase the time delay
between pulses. I'm going maybe 30' at most and so far I've been lucky. I
wish I could have
had it working the other day during the solar flares. That would have been a
good test - aye?


I'd guess you should be fine with 30' runs. I ran three DS1820's on
about 35' of twisted wirewrap wire (3 wires though) during one weekend
project.
 
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