Cogenerating Passive Solar Greenhouse
Wild Branch Valley Farm
Craftsbury, VT
Earthbermed mushroom cave cogenerating heat for and with a 20’ x 48’ greenhouse.
Gunite built ferro-cement cave offers 2 separate mushroom fruiting rooms made of sterile cement. Glass blocks offer indirect lighting options for light sensitive species of mushrooms.
East-West access allows for large solar gains into south facing cave walls during the winter months. Full gunite cement floor and gardening beds allow for thermal mass enhancement with radiant heat system ensuring optimum growing temperatures.
Woodfired boiler/steam generator and cooking oven offer renewable source of heat, substrate pasteurization, and space heating during the deep winter when temperature swings are their largest.
South facing wall absorbs large amounts of heat and releases it during the night and autumn season. Planter beds are easily formed with gunite and can be resurfaced with colored plaster, stone, and brick.
Natural light offers energy savings in a fruiting room inside the earthbermed cave. Electrical boxes, and other utilities are easy to run within the gunite matrix.
Use of a conventional greenhouse structure made this project fast and fun. Thermal mass alone kept the inside of this greenhouse at 30 degrees with outside temps as low as –15. Current design modifications include addition of a bubble insulated second skin during winter months.
