Design, Identification and Control of a Fruit Dehydrator System


Lim, Esther Hee Ying and Tan, Ai Hui and Cham, Chin Leei (2022) Design, Identification and Control of a Fruit Dehydrator System. In: Postgraduate Colloquium December 2022, 1-15 December 2022, Multimedia University, Malaysia. (Unpublished)

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Fruits and vegetables are considered perishable foods because of their high moisture content. Due to the production quantity, the consumers may not have enough time to relish this food. Food dehydration is one of the methods for preserving fruits, herbs and vegetables to maintain their taste and aroma, and for ease of storage. A dehydrator system may exhibit nonlinear dynamics in the heating and dehydrating process. From an engineering point of view, the related thermodynamics are nonlinear in nature and do not satisfy the superposition principle. This means that the output temperature is not directly proportional to the input power provided to the heaters. Identification of the dehydrator and the subsequent design of the controller are thus important for optimum performance of the dehydrator. The performance of the dehydrator is justified by how well the output temperature can be controlled by the input power. In this research, a dehydrator system is to be designed and constructed. The system parameters are to be identified so that they can subsequently be used to design the controller. The effect of the model parameters on the final output temperature and efficiency of the dehydrator will be studied. This research work can be considered important because dehydration of food involves the elimination of moisture from food in order to make preservation much simpler and give the food a longer shelf life. A fruit dehydrator of size 47.8cm x 69.0cm x 103.8cm, which consists of a dehydrating chamber with two infrared heat lamps as heaters, five direct current blower fans and electronic circuitry for control, is constructed to remove moisture from fruits. The chamber is heated up directly using the two infrared heat lamps, which are located at the two sides of the dehydrator. When the humidity in the chamber rises above the setpoint, the direct current fan will be triggered to extract the humid air away from the chamber. It was found that the temperature in the dehydrator is quite uniform, and the uniformity can be increased by increasing the air flow rate. It is concluded that a better model with optimal model parameters can better control the temperature of the dehydrator. An increase in the power to the heater and air flow circulated in the dehydrator system could reduce the energy required and enhance the efficiency. The main observation is that an optimal combination of heater power and air flow rate could dry up the fruit inside the dehydrator with higher efficiency compared to the use of higher temperatures, which may damage the fruit texture.

Item Type: Conference or Workshop Item (Other)
Additional Information: Periodic Research Publication (Faculty of Engineering, MMU)
Uncontrolled Keywords: Identification, Modelling, Control, Dehydrator systems
Subjects: T Technology > TJ Mechanical Engineering and Machinery > TJ255-265 Heat engines
Divisions: Faculty of Engineering (FOE)
Depositing User: Ms Nurul Iqtiani Ahmad
Date Deposited: 15 Dec 2022 07:04
Last Modified: 15 Dec 2022 07:04


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