Some big changes have taken place over the past year at Prairie Oaks, thanks to the dedicated and persistent hard work of many neighbors, friends, volunteers, and workers. This includes some major renovations to the shop: the installation of new lighting and insulation in all of the walls and ceiling, the construction of an attached greenhouse, and the organization of areas for woodworking, vegetable processing, and machinery repair.
Greenhouse planning and construction began in late 2017 and finished in the spring of 2019. The greenhouse is 14ft x 11ft (156 square ft) with built-in cedar planting boxes. The greenhouse was also installed with a Ground to Air Heat Transfer system (GAHT). With a GAHT system, the ground under the greenhouse is used as a battery to store heat sequestered from passive solar heat and thermal mass of the soil.
When the temperature inside the greenhouse reaches 80 degrees, a small fan kicks in to force hot air from the higher points of the greenhouse into plastic pipes that are coiled and buried 6 feet under the ground. If the temperatures exceed 90 degrees, an exhaust fan kicks in. These processes are controlled by thermostats. When temperatures drop below 60 degrees, the GAHT process is reversed by recalling the stored heat from underground. We also have a very small heater connected to a thermostat that kicks in if the temperatures fall below 55 degrees. While the temperature regulations are not fully perfected, we continue to experiment with this new system.