To provide a system of supplying carbon dioxide necessary for plant growth without supplying a greenhouse with a combustion gas containing high concentration CO generated through incomplete combustion in ignition and extinguishment.
The system of supplying carbon dioxide includes a combustion burner 1, a heater 2 connected to the combustion burner, a chimney 3 connected to the heater, a bypass path 4 bypassing combustion gas, and a branch feed pipe 6 branching from the bypass path, communicating with a cultivation greenhouse, and branchedly supplying carbon dioxide in the bypass path to the plant cultivation greenhouse PH by switching a switch valve 5. The switch valve is forcibly controlled in an off condition as "forced prohibiting time control" to forcibly block inflow of incomplete combustion gas into the cultivation greenhouse, within a fixed prohibiting time after the ignition and extinguishment condition of the combustion burner is changed.
NAGANO TAKANORI
INO SHINGO
Nozomi Tsujimoto
Morita Takuo