Optimization of an earth-air heat exchanger combined with a heat recovery ventilation for residential building needs

The Earth-Air Heat Exchanger (EAHE) is an energy system able to preheat or to cool a building using air ventilation. The coupling between the earth-air heat exchanger, the Heat Recovery Ventilation (HRV), the bypass and the building is modeled. System inputs correspond to sizing parameters and to meteorological data for several French climate zones. System outputs are composed of two energetic criteria and one economic criterion. A sensitivity analysis is performed to select the most significant variables. For the selected regulation and design parameters, tube radius, tube length, burial depth, air renewal and regulation temperature are the most influential variables. A multi-criteria optimization study is then carried out to determine the Pareto front. The objectives do not evolve in the same trend because when the coefficient of performance increases, the cost of recovered energy increases and the fraction of renewable energy decreases. A multiple-criteria decision making method is finally applied to select the optimal sizing and regulation. The results show that even if the system depends on weather conditions, the system achieves high energy performance for the different French climatic zones.