Solar and Geothermal projects

I have several demonstration projects designed to show how to heat and power a house here in Minnesota.

Some background: Over 6700 heating degree days. 0.6 cloud factor. Temp range of -40F to 100F

Step 1 harness the sun.

I back in 2008 I had solar toughs that produced 180 degree water even when it was -20F. The troughs were different than the normal ones in that the front was completely enclosed making it easier to keep them free of snow and ice. They were also mounted north/south and they had a mirror on the north side to reflect the light back on to the tube.

After they were lost in a fire I picked up this used heliostat from practical solar and set it up so that it shined light in threw the bedroom window. The ROI based on the heat alone is about 10 years. Here is a pic of it in the winter. The snow and ice generally cleans itself off in the winter and rain keeps it clean in the summer.

The plan is now to use a mix of solar troughs and heliostats to harness the sun.

Step 2 Store the energy for when it's not shining.

I picked up 12 pallets of candle wax at an auction for $5 a pallet. The plan is to place coils of PEX tubing in a large tank and then have the wax in the tank. The 180 degree water from the solar troughs will melt the wax and then the wax will provide weeks worth of heat to the house. Earlier I estimated that I needed 250 gallons of wax per day at the coldest part of winter.

Step 3 Use the heat

This step is actually just a regular hydronic heating system. The water flows threw the same PEX tubing that is in the wax tank and goes threw a tempering valve to keep it at around 110F before it is sent to the house floor and radiators.

Step 4 Make electrical power

This is more of an experiment and involves an old screw compressor to make a sterling steam engine.

Step 5 Other projects

I am experimenting with a solar vacuum still. The idea is to use the sunlight to evaporate the water while a vacuum lowers the temperature needed. This will also let me remove the scent that the candle wax has.