Storing Summer's Sun Heat
Let me start by saying that this innitial experiment is being done without any subground insulation of the thermal storage mass (other than the cap over the hole that the hot water will be sprayed into).
I fully realize that I stand to loose a lot of BTU's to the surrounding ground, but I want to find out how much of the heat that otherwise would have been entirely wasted and reflected away or absorbed in the home during summer will be able to be utilized in winter. Since I am doing this on a very low budget, any gain is a gain. My goal is to not spend any more than what I would have spent heating water. That way all additional heat stored and utilized in winter will be free.
I have recently purchsed an older home in need of major renovations. This home was built in 1904 and in the basement there are two large holes in the floor that had something to do with the coal "furnace" that used to heat this home.
The front of the house faces south and has a brick edged front porch with a cement pad. There is a coal shute door in the knee-wall in front of the porch which leads down to the basement. After I replace the roof, I will build solar collectors on both south facing roofs. I have dug an area out in front of my front porch that is six feet front to back , about ten feet wide and three feet deep. This is framed and covered with four single sheets of sliding door glass from two doors (separated the thermal pieces). In this "pit" I will have a parabolic trough with a metal tank suspended above it (under the glass).
Water will be preheated in the collectors on my roof to at least 150 degrees. It will then flow down into the tank in front of the porch where it will be heated by the parabolic collector to above boiling temperature. A pressure relief valve will allow heated steam to be released where it will spray out into the bottom of each of the holes in my basement floor. These holes will be "capped" with a cover of at least three feet of foam insulation. These caps will be constructed at low cost by combining canned spray insulation foam to hold together pieces of (waste)expanded styrofoam which are rescued from heading to the landfill. The steam vapor will spray down onto the bottom of these holes at a rate that will allow it to be easily absobed by the sandy soil beneath.
Since I will not have an insulated "shell" to guard against heat loss, I will be pouring more heat into the ground than what I might otherwise require. As the heated steam (condensing to water) seaps into the ground, it will take heat down with it. At the same time, by it's nature, the greater portion of the heat will eventually migrate back up toward the top where it will remain accessable through winter.
The ground and insulation should prevent me from overheating the house through the summer.
When I get the chance to have several well holes drilled, I will use most of them to store heat in the ground beneath our home on the south end and utilize at least two on the north side of the house to soak up cold air, snow, and ice throughout the winter to help cool the home in summer. I am hoping there will be enough distance and thermal break from soil to allow me to store heat and cold at opposite ends of the house, without cross over.
