IIR document

Naturally circulating collector for heat pumps: initial results.

Author(s) : RIEBERER R., MOSER H.


In Austria, during the last years, more than 100 ground-coupled heat pumps have been installed which use CO2 probes as the heat source. Compared to indirect systems, they offer a reduction of the electricity consumption and a higher efficiency, respectively, due to the natural circulation of the working fluid. Additionally, the application of CO2 implies favourable heat transfer characteristics and it is absolutely harmless to the ground. These advantages and the successful market introduction of the CO2 probe initiated further research activities on a horizontal type (CO2 collector). It is also based on the thermosiphon principle and shall be used as a horizontally installed ground heat exchanger offering the same advantages as the CO2 probe does. For the analysis of the CO2 collector, a test rig has been designed and constructed at the Institute of Thermal Engineering. The experimental results collected so far confirm the suitability of the proposed system. In parallel to the experimental work, a simulation program is under development.

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Pages: 2006-2


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  • Original title: Naturally circulating collector for heat pumps: initial results.
  • Record ID : 2007-1743
  • Languages: English
  • Source: 7th IIR-Gustav Lorentzen Conference on Natural Working Fluids (GL2006). Proceedings
  • Publication date: 2006/05/29


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