Floor Temperature

[[email protected]]

How would you measure the temperature of a concrete floor with a non
contact method? The object is to turn on the floor heat a few degrees
above freezing and relative to floor temperature. In other words a
non contact thermostat set up to keep the floor from freezing. Non
contact is desireable to prevent the sensor from being corroded by
road salt and crap the cars haul in the winter. The present setup
uses a conventional wall thermostat with a minimum temp setting of 50
degrees. In the winter it turns on the heat unnecesarily any time the
door is open for a short time. Drilling a hole in the floor for a
sensor is risky since it is unknown where the floor heat tubing is
located. Would like to do this for < $50. Any suggestions for
sensors, etc appreciated.

BobS

 

[David L. Jones]

How would you measure the temperature of a concrete floor with a non
contact method? The object is to turn on the floor heat a few degrees
above freezing and relative to floor temperature. In other words a
non contact thermostat set up to keep the floor from freezing. Non
contact is desireable to prevent the sensor from being corroded by
road salt and crap the cars haul in the winter. The present setup
uses a conventional wall thermostat with a minimum temp setting of 50
degrees. In the winter it turns on the heat unnecesarily any time the
door is open for a short time. Drilling a hole in the floor for a
sensor is risky since it is unknown where the floor heat tubing is
located. Would like to do this for < $50. Any suggestions for
sensors, etc appreciated.

BobS

A remote infrared thermometer will do that. Often sold as a "laser"
thermometer as commercial hand-held units, but most likely available as a
module, or could be hacked if not.

Dave.

 

[Joerg]

How would you measure the temperature of a concrete floor with a non
contact method? The object is to turn on the floor heat a few degrees
above freezing and relative to floor temperature. In other words a
non contact thermostat set up to keep the floor from freezing. Non
contact is desireable to prevent the sensor from being corroded by
road salt and crap the cars haul in the winter. The present setup
uses a conventional wall thermostat with a minimum temp setting of 50
degrees. In the winter it turns on the heat unnecesarily any time the
door is open for a short time. Drilling a hole in the floor for a
sensor is risky since it is unknown where the floor heat tubing is
located. Would like to do this for < $50. Any suggestions for
sensors, etc appreciated.

Would a contactless IR sensing thermometer work?

 

[Phil Allison]

<[email protected]

How would you measure the temperature of a concrete floor with a non
contact method?

** There is only one non-contact method - a pyrometer.

http://en.wikipedia.org/wiki/Pyrometer

The object is to turn on the floor heat a few degrees
above freezing and relative to floor temperature. In other words a
non contact thermostat set up to keep the floor from freezing. Non
contact is desireable to prevent the sensor from being corroded by
road salt and crap the cars haul in the winter.

** An IR thermometer is affected by the "emissivity" of the surface.

http://en.wikipedia.org/wiki/Infrared_thermometer

http://www.engineeringtoolbox.com/emissivity-coefficients-d_447.html

So reliable readings are not likely off a concrete floor in a busy garage.

The present setup
uses a conventional wall thermostat with a minimum temp setting of 50
degrees. In the winter it turns on the heat unnecesarily any time the
door is open for a short time. Drilling a hole in the floor for a
sensor is risky since it is unknown where the floor heat tubing is
located. Would like to do this for < $50. Any suggestions for
sensors, etc appreciated.

** Well, forget IR.

And also forget coming here with crackpot ideas and specifying an absurd
budget.



...... Phil

 

[[email protected]]

<[email protected]




** There is only one non-contact method - a pyrometer.

 http://en.wikipedia.org/wiki/Pyrometer


** An IR thermometer is affected by the "emissivity" of the surface.

http://en.wikipedia.org/wiki/Infrared_thermometer

http://www.engineeringtoolbox.com/emissivity-coefficients-d_447.html

So reliable readings are not likely off a concrete floor in a busy garage.


** Well, forget IR.

And also forget coming here with crackpot ideas and specifying an absurd
budget.

.....   Phil

Ok, Phil,

How would you do it budget or not? An IR sensor and PIC would fall
the price range. Lets be constuctive here.

BobS

 

[Joerg]

One simple approach would be to put a small phase change sensor on the
floor--e.g. a tuna fish can half full of water, with a piece of glass
epoxied on as a lid and some sort of disinfectant to keep it from going
too scummy.

A chopped LED/photodiode reflective sensor will detect the light scatter
when it freezes. No calibration required--but don't use salt for the
disinfectant.

By the time it freezes you'll probably have the first fender benders
already.

Bob: Why can't you embed a regular NTC somewhere off the usual vehicle
paths? Must be in a place where there are no heater lines. Drill a hole
into the concrete and pot it up really well. Chisel a trench from there
to the wall.

Best would be if this was a stainless encapsulated version or similar
with the top exposed so it catches a freeze early enough. Then figure
out via a test at which temperature you'd want the heaters to come on.

You could also mount it really low on a wall but if this garage or
whatever it is could be visited by the graffiti gang that might be
vandalized.

 

[Phil Allison]

<[email protected]

** There is only one non-contact method - a pyrometer.

http://en.wikipedia.org/wiki/Pyrometer


** An IR thermometer is affected by the "emissivity" of the surface.

http://en.wikipedia.org/wiki/Infrared_thermometer

http://www.engineeringtoolbox.com/emissivity-coefficients-d_447.html

So reliable readings are not likely off a concrete floor in a busy garage.


** Well, forget IR.

And also forget coming here with crackpot ideas and specifying an absurd
budget.

How would you do it budget or not?


** Bury a K-type thermocouple in the damn concrete.

Connect it to a K-thermocouple amplifier and use the output voltage to do
the job.

Interfacing is your problem - pal.




....... Phil

 

[Phil Allison]

"Phil Hobbs"


** I see no sign of that link you promised

To a HP 400A true rms voltmeter ???




.... Phil

 

[Phil Allison]

"Paul Hovnanian P.E."

I think your money would be best spent figuring out how to encapsulate a
contact-type sensor to protect it from ambient gunk.

** Why not just some 5 minute epoxy ??



..... Phil

 

[ehsjr]

How is the floor heat accomplished? Electric coil? Heated liquid
(glycol,water,whatever..)?


D from BC
British Columbia
Canada

I just sent you an email that may be of interest,
based on your location.

Ed

 

[legg]

Drilling a hole in the floor for a
sensor is risky since it is unknown where the floor heat tubing is
located. Would like to do this for < $50. Any suggestions for
sensors, etc appreciated.

Have you tried a builder's stud-locator to map conductor locations?

These are often sensitive to live conductors, as well (apply power
when searching).

This could give you a safe sensor/wire routing option.

I frankly don't see the point of heating a garage floor, when used
only for vehicular storage. What is the aim here - to protect the
heating system from damage?

RL

 

[Phil Allison]

"legg"

I frankly don't see the point of heating a garage floor, when used
only for vehicular storage. What is the aim here - to protect the
heating system from damage?

** More likely to prevent the staff and vehicles from damage - if ever the
floor gets covered in ice.




...... Phil

 

[Spehro Pefhany]

How would you do it budget or not?


** Bury a K-type thermocouple in the damn concrete.

I'm with Phil here.. a hole drilled into the concrete to accomodate
the sensor will yield solid readings. Other methods are unlikely to do
so.

Connect it to a K-thermocouple amplifier and use the output voltage to do
the job.

Interfacing is your problem - pal.




...... Phil

Best regards,
Spehro Pefhany

 

[Rich Grise]

....
Shame you can't measure either the resistance or working fluid exit
temperature of the under floor heating pipes.

Well, the ends of either the heater wires or the heat tubes are right
there at the power supply - either put the heater in a bridge and control
it that way; if it's a liquid we need more information - for example,
could you slide a thermistor up the line, catheter-style?

Good Luck!
Rich

 

[Rich Grise]

One simple approach would be to put a small phase change sensor on the
floor--e.g. a tuna fish can half full of water, with a piece of glass
epoxied on as a lid and some sort of disinfectant to keep it from going
too scummy.

A chopped LED/photodiode reflective sensor will detect the light scatter
when it freezes. No calibration required--but don't use salt for the
disinfectant.

This is a non-starter - he wants to heat the concrete _before_ it freezes.

Hope This Helps!
Rich

 

[_]

Have you tried a builder's stud-locator to map conductor locations?

These are often sensitive to live conductors, as well (apply power
when searching).

This could give you a safe sensor/wire routing option.

Or wet the floor and crank the heat up; the places where the lines are will
dry first.