International Energy Agency Advanced Heat Pumps. Annex II. Vertical Earth Heat Pump Systems. Final Report

摘要

The following summary of study results and conclusions of the IEA Advanced Heat Pumps Annex II, Vertical Earth Heat Pump Systems can be given. Austria, Canada, Denmark, USA and Sweden are the participating countries with Sweden as operating agent. The objective of the study was: to investigate state-of-the-art of the technique in the participating countries; and to assess climate and geological conditions, energy and power demand of normal residential buildings in the participating countries as an input for sizing calculations. A computer model was developed and has been used for calculations of the size of the ground heat exchanger made of various materials in various ground types. Components such as ground heat exchanger elements (pipes) drilling methods, solar collectors and ambient air heat exchangers are described and actual market prices have been collected. The technical potential of the VEHP-technique is assumed to be rather good and no serious barriers to use have been noticed. The economic calculations and considerations show that the VEHP systems are not competitive today due to the relatively high investment costs for installation of the ground heat exchangers, especially in hard ground types. The technical behavior as well as the economy of the VEHPs depend very much upon the size of the plant and on the mean temperature level of the storage. The energy losses for mean storage temperature equal to the undisturbed ground temperature are practically zero. Energy storage at higher temperature levels is economically only possible for large systems. It is recommended that further research and development shall be concentrated on development of less expensive ground heat exchangers. (ERA citation 10:020888)