The temperatures in the biomeiler pile are measured with thermocouples buried in several locations. Nine of them are found at three heights (1’, 2’, and 3’ above the ground) in the inner core, outer core, and mantle of the pile. The graph in today’s post shows the temperatures measured by thermocouples at 3’ height. These sensors are buried 1’ below the upper surface of the pile. A sheet of Reflectix, a tarp, and some snow lie above the top of the pile.
The temperatures measured in the inner and outer cores were identical for the entire month. In consequence, the two lines on the graph (IC3 and OC3) entirely overlap.
Last month, I described the discovery of an ice cap lying about 6” beneath the surface of the pile and having sufficient radius to reach the middle of the mantle layer, where the vent pipe lies. I recently did more exploration and found that the ice cap has receded. Its radius is now only about 6” past the outer core of the pile and its depth is now about 8” beneath the surface. So, there has been a measurable change, but there still remains a considerable volume of ice even after continuous melting during this first month of summer.
The insulating effect of the wood shavings and the heat rejection by the Reflectix sheets are, without doubt, the two effects most responsible for preserving the ice cap. I suspect that the main cause of melting is the heat brought in by the air passing through the vent pipe. Since that amount of heat is small in comparison to the heat absorbing capacity of the ice cap, it is quite likely that the pile will be able to cool the coop all summer!
For these pictures, I pulled back the Reflectix and the tarp. In this picture, you can see that the ice cap lies about 2” below the wire that surrounds the outer core of the pile.
You can see that the surface of the pile has fissures and shows evidence of subsidence. There are elevated rings over the fencing surrounding the inner and outer cores. At the perimeter, the pile has dropped 2-4” below its original height.
In many places the surface has bowl-shaped depressions. In the higher areas, the pile collapses 6-8” under the pressure of kneeling on it. I suspect that much of the surface is held up only by the friction between the wood shavings. The “fluffiness” of the pile is undoubtedly contributing to its insulative value.
While there are still birds in the coop, I will leave the pile intact to continue making use of the cooling effect. However, once the birds have been moved to the freezer for the winter, I will remove the Reflectix and the wood shavings from the upper surface and unwrap the sides to hasten the melting of the pile. I can’t disassemble the pile if it is frozen and I would like to make upgrades before the coming winter.
I find myself wishing the inside chicks will benefit from this cooling effect and that you will be able to duplicate the cause for benefit next year!
The birds in the coop ARE benefitting from the cooling effect.
They have remained inside and comfortable for nearly a month past the normal moving date.
We will definitely attempt to recreate and/or improve the cooling capacity for the future.