Using a automotive O2 sensor for other things

I've designed systems using these lambda sensors way back in the early 80's...

They are routinely used in flue gas measurements to enable optimum burning efficiency of boilers... So your application isn't new by any means, just look for boiler gas flue measuring instruments and you will see lots of companies make them using this type of lambda sensor.

John.

Many thanks John, that's just the sort of information I was after. I routinely use a flue gas analyser but I can't use it in a furnace because the atmosphere can be up to 20% CO which would not do it a lot of good! Sounds to me that my plan to use several sensors permanently installed is viable. I'll get on with it and perhaps add to this thread my results.

Steve

can we use O2 sensor to measure the ambient air quality in a crowded hall or a conference room or a marriage reception hall...

No; the temperature of the gas being measured has to be at least 600 F in order for the sensor to work. There are air quality analyzers for just what you want to do, but they are pretty expensive. Your best bet is to listen to the guests and make some changes in HVAC if people complain.

in that case can we use some pre heater - to heat the gas ? will it change the composition...

I hate to discourage innovation but I suspect that if O2 levels in a hall drop to the levels that a auto O2 sensor usually works at you'll be able to tell by the queue of ambulances down the street!

I may be completely wrong in this. They can be had with built in heaters (for cold starts) and perhaps they will work in the ranges you are interested in. I'd be fascinated to know. Does someone?

Steve

Even if the automotive lambda sensor would measure the hall's oxygen level to your satisfaction (we calibrate the lambda sensors in free air), the internal heater would probably have an unacceptably short life.

Eric Schieb

ElectronSpeed

good job hijacking this thread.

Get a parrot

As the original poster I'm inclined to agree with you about the hijack but what the heck I suppose it's all discussion on O2 sensors.

It would have been nice to hear a bit more from people who've used them in a similar situation to what I'm proposing but in all honesty John answered my query straight up. "It's been done before and yes it will work". What more do I need!

you would be better off using a co2 sensor designed for that purpose. calibate to ambiant and trigger start of ventialtion at 400 ppm and full vent should be in the neighborhood of 750ppm. imc require 30cfm outside air per occupant in this use but if the ventialtion is demand based on co2 economy can be maintained as only the required air change would be used. i would use several sensors around the space (at least four and also monitor the return air in the mechanical system) and start with a program configured on average concentration. if a certain area has a dangerous concentration i would look first to air balance.

O2 levels would have to change dramatically before this becomes a problem. Normally, the way it is depleted is by being converted to CO2 (or CO, which is even worse). CO2 will begin to give problems from about 0.5 percent (slight change in breathing patterns), and becomes dangerous at a few percent. Also, because CO2 is relatively dense, there are conditions where it can stick around even when O2 is being replenished. Fully instrumented CO2 sensors are used in the brewing industry, and so are relatively inexpensive.

Fyz

YOU ARE BETTER OFF USING A CO2 SENSOR WHICH WOULD BE INDUSTRY STANDARD. YOU COULD ALSO USE A TRANSMITTER IF THE HVAC IS NOT CONTROLED BY A DDC SYSTEM. THE SIGNAL FROM THE CO2 TRANSMITTER COULD BE USED TO DRIVE DAMPER ACTUATORS TO INCREASE OR DECRESE THE AMOUNT OF OUTSIDE AIR INTRODUCED. IF YOU ARE CALIBREATED TO A 200 PPM OVER AMBIENT LEVEL YOU WILL MAINTAIN A HEALTHY ENVIRONMENT WITH THE LOWEST ENERGY COSTS.

Just beware that some low cost O2 room monitors measure the CO2 and then deduct it from 21% (standard atmosphere) to show the amount of O2 remaining - and they don't like getting hot.

SENSOR would melt in furnace