Several projects aim to develop greenhouse farming in the Northern Québec region, with the aim to promote better-quality, more affordable, and diversified food. In this context, the development of storage systems linked to these greenhouses is underway in villages throughout the region. The local climate results in a short growing season, and night-time temperatures are cold even in summer, making it difficult to grow crops in greenhouses. The aim of a thermal energy storage system is to store the thermal energy available during the day and re-inject it into the greenhouse at night.
There are several reasons for developing a combined numerical model of the greenhouse and storage system: improved control, optimization of future systems dimensions, feasibility study of coupling additional energy systems. Both a greenhouse sub-model and a storage sub-model have already been developed. The aim of this research is to integrate them into a coupled model and then assess the viability of the simulations.
To achieve this goal, the resulting coupled model is analyzed for the first time, in order to determine the necessary adjustments for simulations to closely match reality. This analysis revealed that the model was physically coherent, but that the accuracy of the simulations needed enhancement: simulated temperatures were underestimated at the beginning and end of the growing season and overestimated in the middle. Consequently, a calibration process is planned to redefine the values of uncertain model parameters.
The calibration process consists of a sensitivity study, followed by calibration using a differential evolution algorithm, and an analysis of the performance obtained. This process is initially applied to the greenhouse and subsequently to the greenhouse linked to the storage system. Since the calibration did not yield conclusive results, it became necessary to refine the system modeling, particularly concerning the boundary conditions of the storage system.
An examination of the digital storage model simulations uncovered seasonal thermal storage dynamics. Integrating this behavior into the numerical model has improved the accuracy of simulations of energy exchange between the greenhouse and the storage system, as well as the internal temperature of the simulated greenhouse, resulting to a root-mean-square error of 1.9°C.
This advancement now allows for the optimization of future storage device characteristics and the exploration of the feasibility of integrating additional energy systems, such as a solar thermal system.
| Date | 18 Dec 2023 |
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| Original language | French |
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| Awarding Institution | - École de technologie supérieure
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| Supervisor | Didier Haillot (Supervisor), Danielle Monfet (Co-supervisor) & Stéphane Gibout (Co-supervisor) |
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Maheux, T. (Author),
Haillot (Supervisor),
Monfet (Co-supervisor) & Gibout (Co-supervisor),
18 Dec 2023Student thesis: Master's thesis › Master in Engineering: Mechanical Engineering