Analyse d'un système géothermique résidentiel comportant des puits courts et inclinés

Abstract

This thesis is a technical and economic analysis on the use of a geothermal exchanger with very short boreholes angle-inserted into the ground. This particular type of geothermal facility is used for heating and cooling a new house in a northeast suburb of Montreal. The geothermal exchanger under study involves eight boreholes of 12 meters and nine borholes of 23 meters, for a total of 17, inserted from the basement of the house at vertical angles of 35 and 65 degrees, respectively. The thermal load profile is based on a numerical model of the house and its mechanical components. The house has been implemented in the TRNSYS software and its application TRNBuild. The geothermal exchanger is processed from Matlab with a new finite line source model which is more flexible and effective in response times for inclined boreholes. The long-term simulations demonstrate that the axial effects are relatively small when considering a steady mean temperature at ground surface. On the other hand, when the external temperature variations are applied, a marked difference can be observed in the fluid outlet temperatures between a geothermal exchanger with short and inclined boreholes and a standard vertical one with the same total length. However, the studied exchanger dimension is almost doubled in comparison of a standard vertical geothermal exchanger to achieve the same performances. An economic study considering the costs of installation and the impact in terms of performance of the heat pump demonstrates that using a geothermal exchanger with short and droop becomes profitable after 17.3 years in comparison with a conventional one which becomes profitable after 14.6 years.

Date	28 Jul 2011
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Louis Lamarche (Supervisor) & Stanislaw Kajl (Co-supervisor)