Notice the title didn’t say completely finished since the last few steps are to improve the acme screw feed as well as add a water table, ventilation system and wire up a better connector for the torch control. But the paint looks great and the electrical components in a box is great. The part you see cut is intended to be the plate that is the interface between the boiler and the burner. I call it the burn plate. It will go into the opening in the boiler, the holes in the very bottom will allow a resistance heater to light the biomass either pellets or chips, the holes above are for draft. The large hole in the top center is for the auger feed and the remaining holes are on the left, a fire detector sensor and a hole to be tapped for attaching the sensor. The two holes in the upper right are intended to be the swivel point and observation port to observe the flame. I drew the part that you see pictured up in Google Sketch Up. What really impressed me about Sheetcam is that the piece to swing and hide the flame in the observation port was made at the same time from the scrap that was cut out of the auger hole. Sheetcam automatically figured out the hole in this swinging part should be cut as a hole with the offset of the kerf to be on the inside of the hole, then cut the remaining profile as a outside kerf, then cut the auger hole as an inside hole. This was all done in the correct order automatically. Cool! Sheetcam is a great program.
I finished the assembly of the two carriages on the x axes of the CNC machine. The y axis is mounted and this next week the goal is to assemble the carriage to Acme nut connections and build the linear carriage for the y axis. So if all goes as planned next weekend or sooner could be the first prototype test of the machine, the z axis will not be workable but I am sure I can find a way to attach a pencil the axis to see movement. That is a great goal for the week.
My SparkFun package of an FTDI Adapter board and and second board will allow me to reload the firmware on the OpenLog board I ordered in January. I am dreading this a bit, electronics and computer area things are my weakness so I am a bit nervous but will tackle this job and test in a example sketch this week. I’ll bet that will take any free time I may have up but will get me that much closer to my goals.
Earlier I finished the piping for the the two additional zones. A quick recap, one zone will allow a boiler to heat the tank that is normally heated by solar. The second zone is really not a zone but the piping and circulator pump that will add heated water from the chip boiler.
The solar water tank, or solar thermal store has two coils in it, the first coil is heated by the solar loop on the roof. This coil is physically lower in the tank so that the heated water will rise and the sensor controlling this coil is lower as well. This allows the maximum storage from the tank from solar at all times. The second coil and sensor that is intended to be heated from the boiler is mounted higher. The water at the top is hottest and therefore the least amount of energy will be needed and the maximum amount of free energy is used first. Of course solar is not free, it still requires a circulator pump but I assume it to be negligible and therefore in this context free.
Knowing this and assuming that I am going to use an Arduino microcomputer in the process anyway, I am intending to implement the solution in two steps. The first step to wire and shrink wrap a thermistor and run the thermistor back to a breadboard, and display the temperature on an LCD. If the temperature is below a certain value, digital write to a relay to turn on the circulator pump. If the temperature is good, do nothing.
In the second iteration of the solution my plan is to add a time chip to the system and make the process more efficient. The logic is this:
8am, no real need for hot water, and there is a good chance the solar will heat the water.
4pm, heat water and maintain until 8pm if needed.
8pm-8am maintain a minimum, lukewarm temp. We’re not a shower in the morning family. Of course on the weekend the program will have to be different.
To implement this 2nd iteration a real time chip will be required. I have found a few, one at sparkfun.com
and a second one at
I am inclined to the second link, the board is cheaper with a built in battery holder and battery shipped with the product for $14.99
And the yourduino option for $9.00