How it Works
Hold on, you grow produce during a Minnesota winter? Yes! Here’s how it works. Our greenhouse is composed of two main sections: the vestibule and the planting room. The vestibule is closest to the outside temperature. This space is used as storage, but it also heats up the outside air before it enters the planting room to make sure our plants are never shocked by cold air moving in.
Another door separates the vestibule from the planting room. In the planting room, most of the science occurs! The passive solar, of our passive solar winter greenhouse, comes in through the opaque panels on one side of the roof. These celled polycarbonate panels trap and reradiate heat into our greenhouse. Energy from the sun enters during the day and heats up the space. At night, this same heat bounces around the greenhouse to keep it warm. Plus, we pump some of this heat through tubes underground to heat up the soil, which continues to radiate heat after the sun goes down.
We aim to keep the greenhouse between 40-80°F, and if it gets too hot a fan will pump the hot air near the top of the greenhouse and back outside. In additional to cycling hot air, our greenhouses uses thermal masses or heat sinks to trap heat inside. Water has a very high specific heat. This means that is takes a lot of energy to heat up water, and it takes a while for it to cool down. We utilize this characteristic of water by having large barrels of water in the greenhouse back outside.In additional to cycling hot air, our greenhouses uses thermal masses or heat sinks to trap heat inside.
This is passive solar technology because it does not require the input of electricity, but instead uses the power of the sun. However, there is an electric backup heater to make sure our plants survive long stretches of cloudy winter days.These heat up during the day and slowly radiate heat as they cool down over night. The heat sinks help prevent extreme changes in temperature between day and night.
Solar Panels? In the works! Stay tuned for updates on how we are planning to use the solar panels to supply our electricity!