Greenhouse CFD Simulation for Searching the Sensors Optimal Placements

摘要

The trend of modern greenhouse microclimate's control is becoming more and more intelligent. All kinds of sensors play the important role for monitoring and controlling the microclimate elements, such as temperature sensor, illumination sensor, humidity sensor and carbon dioxide density sensor, etc. They will inspect the greenhouse microclimate day and night. And their feedback values will be used for controlling the microclimate by manual or automatic operating for the greenhouse actuators. The control performance and accuracy is depending on the sensors placement positions in greenhouse. It is well known that greenhouse is a complex and unstable microclimate system and can be easily disturbed by the internal actuators and outside environment. How to place all kinds of sensors is depend on the engineers' experience in most cases. Trial and test is usually the only way to get the reasonable sensors positions. This widely used way has big limitation, no one can judge if these sensors are really placed on the right positions, or even if they are on the optimal positions. Right sensors positions are important for monitoring greenhouse, and optimal sensors placements can effectively improve the monitoring and controlling quality of greenhouse, decrease the number of sensors and save energy. CFD simulation can correctly predict the greenhouse microclimate status, and can provide 3D results of the simulation process, it will help the engineers to find the optimal sensors position easily for the complex and comprehensive microclimate situations. This paper will investigate a method for optimal sensors placement using the CFD simulation. A greenhouse CAD model with its main accessories is built by a real greenhouse dimensions. And the rough steps of CFD simulation are introduced in this paper. In the end, the microclimate simulation results and the optimal sensors placements are discussed in detail.