Wood Boiler Greenhouse

Our greenhouse this year is being heated with an EPA-certified, wood burning gasification boiler. This boiler uses a two-stage burning process for higher efficiency. In the first stage, wood is burned at a lower temperature, releasing combustible gases (like carbon monoxide and hydrogen). In the second stage: these gases are re-burned in a separate chamber at very high temperatures (1,800°F+), producing more heat and cleaner emissions. The boiler is set to keep its 250 gallons of circulating water at 170 degrees and is looped through greenhouse radiator fan that blows hot air off its interior water pipes to heat the greenhouse under thermostatic control.

Compared to a single combustion chamber boiler, the two-stage process produces much less creosote, smoke, and ash and operates at 80-90% efficiency. It requires dry, seasoned wood to function properly (less than 20% moisture content). We sourced hardwood off-cuts from a nearby lumber mill for this season.

We have been running it since Feb 15th learning how much wood is required to maintain the temperature in the mid to upper 60s and have so far been successful. This February and March has provided good challenges with intermingled cold and warm temperatures. We got the hang of the heat control in a week or so noting 12-16 hr wood loading intervals when temperatures are cold. The heat from the sun on our clear 35-50 degree days quickly pushed daytime temps into the 80s and our team has now restored the greenhouse fan and vents and set them with thermostatic controls. We started well over a thousand plants including mix vegetables, herbs, and flowers from seed on 2/28 and continue to regularly seed more as we head into the growing season with excitement and toward becoming a Winchester community resource for seedlings, produce, herbs, and flowers.

Thanks to Dottie, Erin, Bill, Jarvis, Ryan, and Jim for all the variety of ways this team has helped to make this greenhouse experience happen!!