Current Heater Testing at Lopez Labs

February 11, 1997

Today, we did run 5 of a 10 run series with a controlled wood load. All pieces have the same moisture content, and are split from hardwood boles between 8" and 14" in diameter. The wood load consists of 8 pieces and 2 lb kindling. The pieces are stacked in a 2-3-3 log cabin configuration. The two top rows are stacked tight, with the bark down (see fuel load photo).

Data is available in Excel format.

We used a Kodak DC-50 digital camera to document the burn progressions. Below are the images from today's test run, which finished at 11:30 a.m.

Today, we replaced the standard loading door with a solid sheet of ceramic glass to get a better view of the fire. There were some glitches with the stacking, and the burn has a few slow spots, and the photographic progression is quite different from yesterday. Efficiency is down about 3% from yesterday

`RUN No. HK-f25`
`Number of Pieces`	`8`	`Standard Deviation`
`Total Weight, lb`	`73.5`	`2.66`
`Wood Moisture %`	`16.8`	`0.46`
`Fuel Surfac/Vol`	`2.35`	`Accuracy`
`Average Stack Temp, F`	`391.4`	`+/- 0.1`
`Average O2 %`	`14.3`	`+/- 0.2`
`Stack Dilution Factor`	`3.19`
g`/kg CO`	`20.8`	`estimated`
`Combustion Efficiency %`	`97.64`
`Heat Transfer Efficiency %`	`69.93`
`Overall Efficiency %`	`68.28`	`+/- 1.5`
`Average Output, 24 hrs, Kw`	`4.3`

	2 minutes
	5 minutes
	10 minutes
	15 minutes 1" air slot at bottom of glass was closed after this photograph
	20 minutes Spacing is a little loose on the top row, and burn will slow in upcoming frames
	25 minutes
	30 minutes
	40 minutes
	50 minutes Top right piece rolled at 40 minutes and was poked back. Note increaced flaming, spike in stack temperature
	60 minutes
	70 minutes
	80 minutes
	90 minutes
	100 minutes Pile fell over at 90 minutes and was poked Note increased flaming, spike in stack temperature Glass temperature: 550F
	110 minutes
	120 minutes Test ended at 130 minutes Still 4 lbs fuel burning. Compare with yesterday
	0 minutes

Also, we are running some bake oven tests on a prototype heater.

In addition to a continuation of the combustion testing we will also be looking at:

measuring the heat output from a domestic hot water coil
measuring the relationship between required clearances to combustibles and heater wall thickness and material.
testing bakeoven performance

Bakeoven Tests

January 18: 10:30 a.m.

We've switched to an infrared thermometer which gives instantaneous surface temperatures with a simple "point and shoot" operation. The graph below shows surface temperature readings for the oven floor, back, ceiling and side. It's -25C outdoors, so we're firing the heater with about 70 lbs. of wood. The last time it was fired was yesterday morning.

Christmas 1996 Tests

This page last updated on April 5, 2003