Solar water heater temp sensors? Buy where?

[Bill]

Anyone know where I can buy water temperature sensors for a solar
water heater system?

I want the kind which would screw into the water pipe with say a 1/2
inch fitting. Also called "on-line". And I could use a "T" fitting at
the water heater and at the pipe on the roof, then screw these sensors
into the "T" fitting (is the idea).

I'm designing/programming my own controller, so just need the sensors.

 

[Curbie]

Thermocouple (produces micro-volts) - Google: Type K Chromel / Alumel
Thermistors (produces resistance) - Google:5K NTC & 10K NTC
Calibrated Sensors - Google: LM34 for (F) or LM35 for (C)

http://www.jc-solarhomes.com/making_temperature_probes.htm

Good luck,

Curbie

 

[Curbie]

(Pushing my luck just a bit) Have you come across a similarly
inexpensive flow-measurement method?

Morris,

manometer?
http://www.efunda.com/formulae/fluids/manometer.cfm

Curbie

 

[David Lesher]

Thermocouple (produces micro-volts) - Google: Type K Chromel / Alumel

There is no reason to use them;

Thermistors (produces resistance) - Google:5K NTC & 10K NTC
Ditto

Calibrated Sensors - Google: LM34 for (F) or LM35 for (C)

These work well and are dirt cheap. I made small forms out of paper and clay to
put them on the pipe, and poured on epoxy.

 

[Bill]

Check out youtube.com for Arduino ideas.
Thanks, but I will be using a PIC microcontroller and assembly
language / C.

 

[David Lesher]

Thanks, but I will be using a PIC microcontroller and assembly
language / C.

There are I2C and similar digital output sensors that are quite cheap.

 

[daestrom]

Anyone know where I can buy water temperature sensors for a solar water
heater system?

I want the kind which would screw into the water pipe with say a 1/2
inch fitting. Also called "on-line". And I could use a "T" fitting at
the water heater and at the pipe on the roof, then screw these sensors
into the "T" fitting (is the idea).

I'm designing/programming my own controller, so just need the sensors.

I've experimented with 'One-wire' temperature sensors from Dallas
Semiconductor. They support multiple sensors on a bus and a separate
interface plugs into USB for PC monitoring.

Instrumented my furnace, GFX-heat-exchanger, attic/basement and an
outdoor reference. Learned a lot in the process. Unfortunately, a
thunderstorm seems to have induced enough current/voltage in my wiring
(just used untwisted telephone wire) to fry them somewhere between attic
and basement.

Now I'm in a new house so may take on a similar project here in TN

daestrom

 

[Neon John]

On 12/28/2010 6:21 AM, Jim Wilkins wrote:

Jim...

Those are approximations but I'd rather just memorize the actual
values. One of the handiest value to memorize is that 1 atmosphere is
exactly 760mm of mercury at standard gravity. 101.325 is the
conversion to kPa. 101.3 is easy enough to remember.

I'm making progress - but I still have a _long_ way to go.

Your 10m/Atm approximation has been added to the heap. I did at least
quintuple check the calculator, without spotting any errors - but a 2.2
km water column seemed too good to be true.

It is. Sanity check. 1 atm = 760mm of mercury. mercury's density is
13.54 (another handy one to remember) so 760 * 13.54 = 10,290 mm of
water. About 10 meters or 33 feet.

Morris, something that you'll find invaluable, especially if you
insist on working in those execrable SI units is this little program

http://joshmadison.com/convert-for-windows/

Convert converts just about anything to just about anything. I'd hate
to think about life without it.

Usually when something looks too good to be true and there don't appear
to be any errors, it's time to talk to someone who's got a better handle
on things.

I didn't go through your calculation but I'd say that you probably
mixed up units, especially with the SI pascal tossed in there for bad
measure.

John

 

[Curbie]

AOL - Someone (you perhaps?) recommended it a year or two while back. I
downloaded it and have been an enthusiastic user ever since.

Me too!

 

[Curbie]

The 'century' to 'day' conversion and vice/versa seems problematic.

Never tried it before, but it seems to be neglecting leap year days.

Curbie

 

[Winston]

Me too!

I just downloaded it.

After changing Options>Preferences>Tabs>(UNCHECK) 'Multiple Lines'

...it works properly under Ubuntu Wine

Thanks!

--Winston

 

[sno]

Me too!

I confess...it was me (I think)....glad to hear i was able to help some
people....

have fun....sno

--
Correct Scientific Terminology:
Hypothesis - a guess as to why or how something occurs
Theory - a hypothesis that has been checked by enough experiments
to be generally assumed to be true.
Law - a hypothesis that has been checked by enough experiments
in enough different ways that it is assumed to be truer then a theory.
Note: nothing is proven in science, things are assumed to be true.

 

[Curbie]

I confess...it was me (I think)....glad to hear i was able to help some
people....

"Anybody know where to get a small steam turbine?" thread.
Yes, it was your post that got me on it, thanks.

Curbie

 

[Neon John]

I just downloaded it.

After changing Options>Preferences>Tabs>(UNCHECK) 'Multiple Lines'

..it works properly under Ubuntu Wine

I'm a purely Linux (Ubuntu) shop too. It has always worked under
WINE. I've chatted with the author a couple of times regarding a
Linux port. He sees no need (and I have to sorta agree) as long as
Wine works. He is very interested in any Wine related problems so you
might consider forwarding this little problem to him so he can fix it.

John

 

[Winston]

I'm a purely Linux (Ubuntu) shop too. It has always worked under
WINE. I've chatted with the author a couple of times regarding a
Linux port. He sees no need (and I have to sorta agree) as long as
Wine works. He is very interested in any Wine related problems so you
might consider forwarding this little problem to him so he can fix it.

Good thought, John.

I assume you see the same little display issue?

I sent Josh a note about that just now.


--Winston