22 May 2008

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.