Current Heater Testing at Lopez Labs

February 17, 1997

(9:30 a.m)

Today, we did run 8 of a 10 run series with a controlled wood load. All pieces in a given run have the same moisture content, and are split from hardwood boles between 8" and 14" in diameter. Today's wood load consists of 9 pieces and 2 lb kindling. The pieces are stacked in a 3-3-3 log cabin configuration. The two top rows are stacked tight, with the bark down (see fuel load photo).

For today's run, the wood had several percentage points less moisture than Friday. Pieces were a little larger, and the load was 17 lbs more. Efficiency was a couple of percentage points higher at 70%.

It is a little early yet to start drawing conclusions, but our basic thesis is that wood sizing and stacking has as large an influence on heater performance as any other factor, including heater brand.

The stacking of the bottom row was changed from 2 pieces to 3. This resulted in a faster fire, with less excess air (lower stack oxygen). Compare today's photos and graph with Friday, and the day before.

`RUN No. HK-f27`
`Number of Pieces`	`9`	`Standard Deviation`
`Total Weight, lb`	`70.2`	`2.18`
`Wood Moisture %`	`17.1`	`0.35`
`Fuel Surfac/Vol`	`2.66`	`Error:`
`Average Stack Temp, F`	`378.0`	`+/- 0.1`
`Average O2 %`	`14.09`	`+/- 0.2`
`Stack Dilution Factor`	`3.07`
g`/kg CO`	`20.01`	`estimated`
`Combustion Efficiency %`	`97.73`
`Heat Transfer Efficiency %`	`71.38`
`Overall Efficiency %`	`69.8`	`+/- 1.5`
`Average Output, 24 hrs, Kw`	`4.3`

Click on thumbnails below for larger image.
Click HERE for a continuous set of large images

	2 minutes Kindling has different arrangement, some pieces in front of pile, left to right
	5 minutes
	10 minutes The top right piece has just rolled over to the right.
	15 minutes 1" air slot at bottom of glass was closed after this photograph
	20 minutes
	25 minutes
	30 minutes

	40 minutes
	50 minutes Wood stack collapsed See next photo

	53 minutes
	70 minutes
	82 minutes
	90 minutes Fire was poked after reading
	100 minutes Fire poked after reading
	110 minutes
	120 minutes Compare with previous test
	0 minutes

This page last updated on April 9, 2003