مدل جعبه سبز برای دمای لوله بر اساس رگرسیون خطی

Since the physically-based model is still more precise under certain conditions, a third model, called grey-box model, is proposed as a combination of the physically-based and the LR model calculating every time according to the more advantageous one of them. Based on measured data, the grey-box model is the most precise model. In addition, this model has lower computational demand than the physically-based model.