Sometimes no news actually is good news!
We had a very smooth month of December, with very few issues. Careful monitoring of system performance during the first few months of operation led to several upgrades in the control strategy, some of which were made at the end of 2012. Broadly speaking, we’re always looking for ways to smooth out and extend the pellet boiler operation and minimize the use of the oil backup.
We’re pleased to report that the oil boilers have used a total of 7 gallons of oil from day 1, the bulk consumed during initial tune-up and system testing. The remainder of the usage actually occurred during times when the pellet boiler could have kept up with the building’s requirement for heat. In other words, this operation was a mistake that has now been corrected in the control algorithms. We find unnecessary use of backup boilers to be both very common in other installations and easily preventable if you’re interested in doing something about it. Why not use the renewable energy system as much as possible?
The photo at left shows the cumulative ash cleaned out of the system as of December 31. Not bad for nearly 13 tons of pellets! The crew doing the boiler maintenance and cleaning reported that the quality of the ash is exceptional, and that it represents a very clean and efficient burn. (Never mind that this crew was from Froling Energy! However, they see many other boilers requiring cleaning/maintenance and have ample exposure on which to base a comparison.)
Another encouraging point of comparison between Xylogen’s operation of this pellet boiler and the operation of other, identical pellet boilers elsewhere is that we have a very low number of boiler starts—around 500. This is easily half or even one-third the amount typically seen in other boilers at this stage in the heating season. Why does this matter? The fewer times the boiler starts, the less wear and tear it experiences. Also, the startup is the least efficient portion of the entire combustion cycle. We’re doing pretty well here, but have just instituted some changes to do even better.
The original 13 tons in the external pellet storage bin were nearly depleted on January 2, when a small delivery was scheduled. The delivery allowed us to buy a little time to make a few adjustments to the bin before it is fully refilled. The load cells will be adjusted to provide us a more accurate measure of the rate at which the pellets are being consumed.
Based on previous consumption records, we estimated that it would require about 36.5 tons of pellets in a typical year to satisfy the heating requirements at the school. We’re approximately one-third of the way through this amount and obviously eager to do better than the projection!
With that goal in mind, we obtained permission from the school to reduce the space temperatures during the recent vacation, allowing us to conserve some fuel. No point in heating an empty building to normal levels!
We’ll keep you posted with more updates as the heating season progresses. Feel free to send us questions or comments (below, or by email).