| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1712609 | Biosystems Engineering | 2007 | 12 Pages |
In storage rooms for agricultural products, there are losses due to poor temperature distribution. To control temperature distributions in process rooms filled with obstacles, a three dimensional dynamic model is required to calculate the three dimensional dynamic responses product temperature distribution in three dimensions as a response to changes in process inputs such as ventilation rate and inlet temperature. In this study, a data-based mechanistic model for temperature responses at different positions in both airspace and obstacles was developed. In the first step, plastic balls with known characteristics were used as obstacles. During the experiments, step increases in air inlet temperature were applied while the airspace temperature and the air inside the balls were recorded. The simplified refined instrument variable algorithm was used as model parameter identification tool to obtain the best model order and parameters. Using model compacting, several physically meaningful parameters were found to represent the temperature distribution between the products and the airspace.A third-order transfer function developed from the air inlet and airspace temperature data enabled the dynamic response of airspace temperature to be explained. A local volumetric fresh air concentration β1 was determined from the temperature distribution in the airspace with a high coefficient of determination R2 >0.99 and a low error 0.1 °C.A first-order transfer function model proved to be sufficiently good in describing the heat transfer from airspace to obstacles with a high statistical significance (R2>0.99). In this model, a parameter related to the heat transfer coefficient α2 was found to represent the temperature distribution between the obstacles.The values of β1 and α2 in the model could be used to design a control system for real time monitoring and the online adaptive control of the temperature distribution in the process room in three dimensions.
