lambda control boilers and "gourmet wood"

[pybyr]

As I was picking through the remaining dregs of my wood supply yesterday, another question crossed my mind as regards lambda-controlled boilers:

The "fixed setting downdraft" boilers seem to really "shine" when fed with relatively small splits of rather dry wood, and, at least based on my own experience, as well as what I have heard from others-- encounter real handicaps- "bridging" of fuel, failure to achieve or sustain good hot consistent gasification, etc, if wood is on the large size and/ or under-seasoned. My hunch is that under such circumstances, there is an effect where excess air tends to "blow out" the combustion more rapidly than it can build up higher temperatures.

It'd be really intriguing to see tests run with similar wood (size, species, moisture content) with both lambda mode enabled and lambda mode disabled.

IF a lambda-controlled boiler were less prone to "indigestion" with less than ideal wood, that might be a bigger selling point than a few % efficiency.

 

[TCaldwell]

Trevor,that is one of the theoretical beauties of lambda or o2 control, to adjust p/s air to maintain setpoint irrespective of moderate wood differences. The degree of success dependes on the controller format or algorithm, being designed for the process. In that becomes the challenge.

 

[Singed Eyebrows]

My next boiler will be Lambda controlled. I want to be able to just chuck wood in it & walk away. Efficiency is not a concern for me. The Froling in Europe has an auto light option & this would be a great selling point for me. The Kunzel/Lambda in Europe also has auto lighting & will burn any wood you throw in it including a load of kiln dried small scrap that would probably give other boilers fits. Don't know how they are going to fix the bridging problem though Trevor, Randy

 

[jebatty]

I want to be able to just chuck wood in it & walk away. Efficiency is not a concern for me.

Solved by Nature a long time ago -- how much wood can a woodchuck chuck?