Étude de l'efficacité de l'utilisation d'un puits canadien pour augmenter la performance d'une thermopompe à air

Abstract

The present work aims to study the possibility of improving the performance of an air-source heat pump by coupling it with an earth-air heat exchanger. An earth-air heat exchanger takes profit of the soil thermal inertia to preheat or precool a flow of air that circulates in a tube that is buried at a certain depth in the ground. When the exchanger is adequately designed, the flow of air can be routed to the outdoor coil of the heat pump at a temperature that is higher than ambient in heating, or lower in cooling, thus improving the coefficient of performance of the heat pump. A single family building with 200 m2 of floor area serves as the base of the study, and the climate is that of Montréal, Canada. The pre-dimensioning of the earth-air heat exchanger is first conducted, following rules of thumb. Then the system, consisting of the building, the heat pump and the heat exchanger is simulated using the TRNSYS software under four main configurations. A hybrid coupling that allows feeding air to the heat pump as well as fresh air to the building appears to be the most efficient configuration. A parametric study is then conducted to quantify the impacts of different parameters on the performance of the system. It shows that the length of the exchanger and the depth at which it is buried have the most impact. The coupling of the air-source heat pump an the earth-air heat exchanger proves its performance from an energy stand point, especially from the increase of the seasonal heat output of the heat pump, which is made possible by a decrease of evaporator defrosting cycles in heating mode, among other things. This decrease is even more notable when demand defrost is considered. However, because of low energy costs, none of the configurations turns profitable in less than 19 years.

Date	17 Oct 2017
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Louis Lamarche (Supervisor) & Stanislaw Kajl (Co-supervisor)