I don't have a RMH, but I do want to try a sand battery heater in the green house.
My test will be creating a sand battery 2ft x 2ft x 12 ft corrugated sides, to simulate the mass of a RMH Two courses of bricks at the base, the remainder will be filled with sand.
I picked up the bed materials today from Home Depot. Spent some time with Jeff Besos ordering heating elements from Amazon today.
My experiment will be placing the different elements within the central 4 feet of the bed.
The heating elements I ordered consist of a broiler element, a water heating element, an industrial immersion heater, a clothes dryer heating element, an eight inch stove top element, 6 PTC elements. So about 150.00 dollars worth of different heat sources that will be placed within that central 4 feet of the 12 ft bed.
I will be using an EL-USB-1-PRO temperature logger set to read at 15 min increments. I will use three candy thermometers pushed into the sand to monitor visually. I have a laser thermometer to check side temps from top to bottom. I only have one day off a week. That one day I will run un-switched to see how hot it will get. 130-140 seems to be the upper limit of a comfortable heated seat so that will be my temp setting when running through the switch.
I will try two different switch types, a water heater switch and a stove bourbon tube style. I will run direct from the solar panel to each element, switching to a different element after a seven day run.
Should I create a void down the center to simulate the RMH chimney?
If nothing else I hope to use the sand battery as a heated seed starting table during my trial run.
Any suggested additions to the experiment?
I do have a 500 watt wind turbine that I considered hooking up to wring some energy out at night but think I'll hold off for the initial trials.
