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The furnace project

I built a furnace for heating up the greenhouse with wood and carbage when the

weather gets too cold.

Copper pipes ready to be attached in the sand container that will be inside the furnace.
It should warm up the glycol-water and maintain the temperature for a quite long time.

Some equipment to be used with the furnace and solar cells.

So the heat will be transferred into the concrete with the copper-pipes by cycling it around the
glycol-pipes to heat up the floor and the air in the greenhouse.
That means: FREE heating!
I have more energy-saving plans for the future but with these systems the greenhouse should be quite warm always when needed.
Additional gas will be used when it gets very cold.
There’s also heating cables inside the floor of the warm side in case of emergency! 🙂
And of course, an electrical heater will be ready with a thermostat if something fails!
Because of the decent insulating, the concrete should maintain the
temperature even for long periods of time after the last heating.
Later on, a warm water boiler might be added to maintain the temperature even longer periods of time.
It can be used with solar cells, furnace or electricity.

Finally, up & running!
As you can see, there’s enough trees to warm up the greenhouse for a long, long time!
After taking this picture I’ve insulated the hoses to prevent cold snow & weather to cool down the hot water.
The hoses will be instulated properly.

The pipe on the left is hotter and warming up the concrete when the system has been running for a while.
The one the right is usually cooler because the glycol-water is coming
from the floor of the greenhouse and has been cooled down by the
I installed a sensor of the thermostat on the left copper pipe, so
the pump will be turned on when the sensor tells there’s a fire on the
When the temperature drops down too much, the pump will be turned off again, fully automatic!

I came up with  an idea to move the warm air from around the furnace into the greenhouse.
And guess what? It really works well!
The same furnace is heating up the floor and air at the same time.
In the future the waste heat will warm up the greenhouse too.
The barrel looks quite small but it’s actually 200 liters.

A fan is sucking the hot air from the furnace.
There’s sensor in the duct to measure the heat coming from the furnace.
There’s a thermostat that starts and stops the fan when the air gets hot enough / too cold.
This fan blew air approx. 80 liters per second.
Heats up the air in the greenhouse in few minutes!

Finally, here’s a sketch for the furnace.