Control-oriented hybrid model of a small-scale refrigerated truck chamber

• Published in: Applied thermal engineering 2023-02, Vol.220, p.119719, Article 119719
• Main Authors: Fallmann, Markus, Poks, Agnes, Kozek, Martin
• Format: Article
• Language: English
• Subjects: Door opening; Experimental validation; Hybrid system; Modeling; Parameter estimation; Refrigeration
• ISSN: 1359-4311
• DOI: 10.1016/j.applthermaleng.2022.119719

Refrigerated last-mile transport of goods has faced rapidly growing importance in recent years. Although hardware components underwent comprehensive improvements to fulfill increased efficiency demands, little was done regarding control strategies. Simple algorithms or restricted consideration of system parts for control design harshly limit attainable economic and ecological flexibilities provided by state-of-the-art hardware. Sophisticated model-based control schemes constitute a promising remedy but lack detailed and computationally reasonable models of the overall cooling application. This article introduces an appropriate dynamic, low-order model to overcome this issue. The mathematical description relies on first principles, features lumped parameters, and comprises temperature evolution and electrical power consumption, allowing for the assessment of system efficiency. Besides the explicit consideration of door openings, incorporating thermal capacities of the insulation walls and the cooling unit’s secondary storage loop stands out. Component’s switching behavior is embedded in the chosen discrete hybrid automaton modeling approach, for which 18.4h of real-world measurement data drive parameterization and validation. An overall fit to validation data of 86.2% and 88.7% for the most significant temperature quantity and total power consumption illustrates the model’s high performance and practicality for control applications, soft-sensors, and fault detection. •Hybrid, low-order model with lumped parameters of entire refrigeration application.•Comprising temperature values and power consumption enables efficiency assessment.•Door openings are considered explicitly as an actual change in system dynamics.•Experimental data drive parameterization, validation, and performance evaluation.•Reliable process insight for model-based control and fault detection and isolation. [Display omitted]