On Thursday, December 20, 2018, Patricia CARBAJO JIMENEZ, a doctoral student in engineering sciences at the Laboratory for Design Optimization and Environmental Engineering (LOCIE), will defend her dissertation titled “Optimization Methodology for a New Concept of a Hybrid Water-Air Solar Thermal System.”
The defense will take place at 10 a.m. in the INES Formation room of the Hélios building in Bourget-du-Lac.
Thesis summary
In response to changes in building codes regarding thermal performance, buildings are becoming better insulated and more airtight, thereby reducing their heating requirements. Ventilation, which is necessary to ensure indoor air quality, thus represents a significant energy loss. Furthermore, the demand for domestic hot water (DHW) is becoming more significant than that for heating. In this context, solar thermal systems can supply a significant portion of a building’s heat needs. This research therefore examines a solar water heater for DHW production and ventilation air preheating. This innovative hybrid operation allows solar thermal systems to adapt to the new distribution of energy demand in high-performance buildings.
The objective of the thesis is to develop a methodology for optimizing the management of solar heat, distributed between the energy carriers water and air, with the aim of maximizing the potential of recovered solar energy and, consequently, reducing the reliance on other energy sources in the building. Initially, the concept of the hybrid solar system under study was validated, and its limitations were identified experimentally in a test house. A numerical model of the system was then implemented in the Dymola environment using the Modelica language and compared with the experimental data. The system’s interaction with the building requires coupling the system model with a building model in EnergyPlus using co-simulation. The numerical simulations thus enable analysis of the hybrid solar system’s behavior and the identification of a solar heat distribution mechanism suitable for high-performance buildings. With the ultimate goal of minimizing energy consumption, the variables most influential on the hybrid system’s performance were identified using a sensitivity analysis, and the selected decision variables were used in a multi-criteria cost–energy consumption optimization. This work thus proposes a methodology for the optimized management of heat recovered by a hybrid water-air solar system. The integration of indoor air quality and thermal comfort indicators in future research could complement this methodology.