[Stoves] Another high performance stove located

Sun Nov 15 11:05:21 CST 2015

Dear Alex

I have a small correction to the rating of ‘about 29’ mg/MJ delivered. First I will note that the guesses about the meaning of terms was pretty close. Not much to quibble about.

They are using 13% O2 as the standardised dilution. Because the Europeans use a different standard dilution for each fuel type, it is not possible to compare stoves burning different fuels without first making a conversion. I have long suggested that all results be reported on an undiluted basis so they can be directly compared. Plus it is easier to teach.

The correction I want to make is that the total PM for the 15 minutes was not divided into the two clear sections of the test, before and after a lever adjustment was made. That is a bit unfair.

The CO/CO2 (COr) chart and Excess Air look like this:

Section 2 is before adjustment and the COr is obviously higher. After, it is sitting on the floor. 

Here is the analysis by section:

Given that Section 4 is after the adjustment, and the COr is 1/8th of Section 2, and given that the PM is likely to be related to the CO under these conditions, it would be fairer to split the PM emissions into sections. The Stoichiometric volume of the fuel per kg being 7.62 cu m shown here:

Then a back of the envelope calculation brings the PM in Section 4 down to 0.12 of the total. That is time and mass-weighted. That drops the PM emitted in Section 4 from 29 to 29*0.12 = 3.35 mg/MJ delivered – about ½ of the rating for LPG.

I used 65% as the average EA which is not strictly true, though it gave the best CO performance. Maybe 85% was closer to the average. The St. volume rises to 8.55 cu m and your number rises to 3.76. Still less than half.

It should be admitted up front that one is a space heater with a long flame section and the other is a cooking stove, so a grain of salt to be applied when making a comparison, but as a combustor it is performing really well. Given its simplicity it is another testament to your multiple achievements in this area of practical devices.

Regards

Crispin

PS All charts above are from the HTP Analysis sheet, v3.0681

++++++++

Andrew,

The measurements made using a Wohler SM 500. It was developed to meet new German requirments for field testing particulate emissions fromwood stoves. The operating manual is at

http://www.woehler.de/uploads/tx_leonexdownloads/22885_BDA-Woehler_SM_500_EN.pdf

It has an interesting method of real time particulate measurement. 

It was testing a one-off gravity feed pellet stove that ran all day at the stove camp which is  shown  in a picture or two at

http://www.mha-net.org/docs/v8n2/wildac15x.htm

Here is the decoder for some of the data previously posted, followed by the data again. 

Data;O2 should be O2 avg, I think.

There are some error factors which may be explained in the manual.

I can share the entire 'as sampled' data set as a google doc if your interested.

Alex

Variable

Description

mstf(mg)

Total suspended particulate matter mass

mst(mg/m3)

Total suspended particulate matter mass concentration in flue gas

mst60(mg/m3)

Total suspended particulate matter mass concentration in flue gas averaged over theoretical 60 minute test

mst_O2(mg/m3)

Total suspended particulate matter mass concentration in flue gas referred to the adjustable oxygen reference value

O2(%)

Instantaneous oxygen reading

O2_avg(%)

15 minute averaged oxygen reading

COv(ppm)

Carbon monoxide given as a 15-minute average

COv_avg(ppm)

Carbon monoxide given as a running average during a test

CON(mg/m3)

Carbon Monoxide air free concentration referred to adjustable oxygen reference value

CON_avg(mg/m3)

Carbon Monoxide air free concentration referred to adjustable oxygen reference value as a running average 

Vols(NL/min)

Sample rate in standard liters per minute (0oC and 0% relative humidity, 1 atm Pressure) 

Vol(NL)

Accumulated sample volume in standard liters

Measurement results:

O2:

	10.6

%

COv:

	137

ppm

COn:

	131

mg/m³

erw. U COn:

	35

mg/m³

COn - U:

	0.096

g/m³

mStF:

	1.7

mg

mSt:

	33

mg/m³

mSt(O2):

	25

mg/m³

erw. U mSt(O2):

	9

mg/m³

mSt(O2) - U:

	0.016

g/m³

Volume:

	44.3

Nl

Duration:

	0:15:00

Date:

	10.07.2015

Uncertainty mSt:

	36

%

Uncertainty CO:

	26.5

%

On Thu, Nov 12, 2015 at 8:03 AM, <ajheggie at gmail.com <mailto:ajheggie at gmail.com> > wrote:

[Default] On Tue, 10 Nov 2015 19:34:59 -0500,alex english
<aenglish444 at gmail.com <mailto:aenglish444 at gmail.com> > wrote:

>Crispin,
>The data summary from the 15 minute test is below.

Alex is there any chance you can repost your table with the
abbreviations expanded and explained?

Andrew

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