TESTS AND SIZING OPTIMIZATION OF COMPACT COLLECTORS FOR GROUND SOURCE HEAT PUMPS
Ground Source Heat pumps (GSHP) have a fast growing success in Europe, but only in new residential houses. The main barriers for the development of GSHP on the retrofit market are linked to ground collectors, due to installation costs and needed area in gardens. The compact collectors of IVT were developed to overcome these barriers, especially reducing installation costs. Compact collectors are commercialized in Sweden and UK but are unknown in France, where the development of GSHP on domestic retrofit market is a major stake. Compact collector systems in Sweden are associated with an exhaust air auxiliary system for reloading and for reducing the number of collectors. This paper describes two field tests of compact collectors, run in France, with special test conditions taking into account french retrofit market characteristics. This paper analyzes the installation process and sizing and the seasonal performances of both systems. Then, this paper presents the results of a software, developed for EDF, which sizes GSHP systems. Tests and design results are compared and analyzed. The main result is that the vertical installation of compact collectors provides high seasonal performances, with a sizing equivalent to an horizontal installation. However, the installation process is, for the moment, hardly adapted to the french retrofit market constraints.