Reports are available at Annex 29 Publications


To demonstrate the economic and environmental benefits of ground-coupled heat pump systems.

Project manager and participating countries

Austria was the envisaged Operating Agent. The participating countries were: Austria, Canada, Japan, Norway, Sweden and USA.


The following work was realised:

1. Studying ideas for improved technical performance and cost of ground-source heat pump systems

  • Heating-only versus heating and cooling systems
  • Open versus closed loop systems
  • Horizontal versus different vertical systems
  • Direct expansion and secondary loop systems
  • Use of different secondary fluids, including CO2
  • Vertical probes of the heat pipe design filled with CO2
  • Direct and indirect cooling
  • Recharging and moisture migration in the ground
  • Extraction of heat from large surface areas, e.g. parking lots, runways etc.


2. Identification of market barriers and innovative approaches to increase system acceptance including

  • Quality assurance measures
  • Ground coil system guarantees
  • Contracting models for reduced initial cost
  • Regulations
  • Tariff structures etc.