[Stoves] SEET Lab in Ulaanbaatar running again in its new home

[Crispin Pemberton-Pigott]

Dear Frank

 

Good questions, all.

 

>50 grams per cu meter is a lot of stuff. I wonder what a cigarette is? 

 

Really high! And lots of CO too.

 

>So all the heat that goes in the room is ‘good’ heat and that leaving the
room is lost heat to do the calculations? 

 

Anything that is lost up the chimney is gone so the point at which the stove
pipe leaves the room is relevant. I have seen a drop in temperature between
the stove and the roofline of 300 C so it is a powerful heat exchanger.

 

>Is the height where the inside-outside heat standard or site specific? 

 

It is site-specific but as the intended audience is in gers (yurts) the
height is very constant. It is about 2.7 metres from the floor. The chimney
is typically 3 metres long and sits on the top of the stove so depending on
the stove height, the amount of chimney poking into the sky is about 1
metre. Generally speaking all stoves have chimneys that are too large in
diameter. That is interesting.

 

>The compressor taking in CO2 free air is making the dilution? 

 

The compressor compresses air. It is filtered to 0.01 µm and put through a
CO2 and water vapour adsorber, filtered again and then sued in the diluter.
It is very simple and effective. The dew point is -100 F. The CO2 is <1 ppm.
The O2 is much higher, about 33% which was interesting to see.

 

>What is used to scrub the CO2 from the air? 

 

I think it is a metal matrix of some kind. It does not get used up. There
are two units and they are cycled. One breathes with ‘wash air’ or ‘sweep
gas’ as it is termed. The other is under pressure for 30 seconds.

 

The CO2 produced is measured real time(?) using IR detection? 

 

Yes. Two channels in parallel, one for the stack and one for the diluter.

 

If CO2 is produced at varying concentrations as the fuel combusts how is it
used as a measure of air dilution? 

 

The CO2 in the stack is measured. Whatever the CO2 in the diluter is at the
time is compared with the stack concentration and a mathematical correction
is made to consider that some of the stack CO2 (and therefore a % of the
diluter CO2) came from the ambient air. Stack/Diluter = dilution factor.

 

We run the dilution between 4 and 300 with 10 being typical.

 

It has to be high enough (using dry air) to prevent condensation (formation
of fog) in the sample so the particle does not think it is PM. This is
calculated based on the moisture content of the fuel and the hydrogen
content that forms moisture when burned. The system can deal with 140 gm of
water vapour per cubic metre of gases. That is a humidity ratio (by mass) of
about 13%.

 

Regards

Crispin

 

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