Guess how many bags* of pellets Monadnock Waldorf School uses each day!

We first fired up the Fröling P4 pellet boiler on October 6 to begin the commissioning phase of the installation.  (Commissioning is the process of tuning up the system to make sure everything works as intended and as efficiently as possible.)  This phase is rapidly closing in a formal sense, as we’re hoping for an inspection as early as today.  However, the beauty of the arrangement we have is that the commissioning never ends.  We’re always looking for ways to improve the operation of the system as that saves us and the customer money.

Here’s some extremely encouraging, and admittedly preliminary, feedback.  I took a look at last year’s oil delivery schedule.  In the period from 10/6 – 10/26/2011, I found how many gallons of oil were burned.  In that same period, there were 340 Heating Degree Days (HDD’s are a simple measure of how cold the weather is).  For the same period this year, there were 351 HDD’s (hard to believe this year was more severe than last!).

All I’ll tell you is that during this period, we burned 27% fewer btus/HDD than the old oil system did last year.  How’s that for a fine start?!

Here’s your job:

How many 40 pound bags* of pellets did we need to burn each day over this period to keep the school warm?

This may help:

  • The school is in an old brick building, with a wing added in the early 2000’s.  No special care was taken with insulation, air sealing, high-performance windows, etc.
  • The overall floor area is about 22,000 square feet.
  • The hours of operation are approximately 7:30-5:30 M-F, with irregular usage outside those hours.

*Of course we’re not using pellets that come in bags!  It’s just an easy measure that many folks are familiar with due to their pellet stoves at home.


Here’s the heart of the heating system at work.  The first picture (illuminated with a flash) shows the feed auger, which is contained in a cylinder that slopes up and to the left.  At the top of the auger, there’s a mirror that allows you to view down into the combustion chamber.

Here’s the outside view: 

And here’s the view into the mirror:

We’re cooking!

Have fuel, will burn…

By the end of Friday, we were able to tie together the essential components to fire up the system for the first time.  This included filling the distribution system (all the pipes and radiators in the building) and checking all the thermostats.  Of course, it was late Friday afternoon, so we had to restrain ourselves and just enter in all the boiler settings and then walk away.

We had a few hours Saturday, so we began the process of firing up for the first time and testing out the operation.  We gradually heated up the buffer tank, which is a large water storage tank that helps to smooth out (or buffer) the variations of heat drawn from the building.  One adjustment we need to make has to do with the way ash is automatically cleaned from the grate in the pellet combustion chamber.  A call to  BioHeatUSA this morning should resolve that issue and we’ll be on our way with some steady heat.

The commissioning process then begins, with a thorough check-out of the controls system.  Occurring in parallel with that process will be the installation of pipe insulation, direct piping of fresh air to the boilers and a number of small odds and ends to wrap things up.  Then we get to show off the job to the inspectors!


Friday was delivery day!  The bulk delivery truck came from Sandri Fuels to fill the bin with 13+ tons.  Very exciting.  Here are some shots.

Pellets are augered up through the truck’s boom and are dropped into the top of the bin.  The truck has a scale on board to measure exactly how many pounds of pellets have been delivered:  26,058.

This last picture (completely out of focus for now!) shows the pellets through one of three sight glasses on the face of the bin.  A quick glance gives an indication of how much fuel is stored.  We also have load cells installed under the bin to tell us how many pounds remain.

MWS Installation Progress

The last few weeks of silence have been bustling with activity.  All of the heavy equipment had already been put in place, so we have been focusing on getting the interconnections in place, including:

the wiring:and

the venting:

and the fuel lines for both pellet and oil boilers (these rigid lines connecting to the square base of the pellet storage bin are for the pellet boiler):

The wiring is nearly complete, with the installation spaghetti reduced to a much tighter and neater form.  The venting will be further sealed and insulated.  Of course, all the pipes will be thoroughly insulated.