Wednesday, January 14, 2009 09:30-15:30, room 1.41-1.42
Convenors: C. Clauser firstname.lastname@example.org, W Gosnold William.email@example.com, L Rybach Rybach@geowatt.ch J. Safanda firstname.lastname@example.org, M Jones email@example.com The symposium addressed in particular aspects of basic geothermal research which have relevance for geothermal energy use. This comprised studies of general interest (such as of the regional thermal regimes in Russia and Algeria, and studies with explicit focus on geothermal energy use.
and poster presentations:
While the audience varied in composition and number during the different parts of the session, the session was attended by up to 30 participants. Each oral presentation was followed by brief discussion consisting of two to three questions or remarks. Following the oral session and during the poster session, informal discussions continued among the various presenters and attendants.
In view of the presentations delivered, the main goal of the symposium was achieved: bringing together the academic heat flow community and researchers interested in geothermal energy use. Various contacts were established within and between the two groups. It can be expected that the scientific expertise of the heat flow community will be used to a greater degree in future efforts to use geothermal heat and convert it into electric energy.
Great efforts had been made to interest and motivate African researchers for the topic of the symposium. These were successful, too, at least partially. There was a presentation from Algeria and the audience comprised several African attendants. These efforts will be continued by the International Heat Flow Commission which hopes to see equally many or more African researchers on the occasion of the next similar symposium.
Aachen, 9 February 2009; Report prepared by Christoph Clauser
Friday, January 16, 2009 09:30-12:00, room 1.41-1.42 Conveners: Y Popov firstname.lastname@example.org, S Roy <email@example.com >
The workshop was aimed to compile and disseminate information on currently used techniques in acquisition and interpretation of geothermal datasets and to stimulate better understanding of experimental data quality in basic and applied geothermics. A major thrust of the workshop would be to deliberate on present-day measurement practices for basic geothermal parameters - borehole temperatures, temperature gradient, heat flow, thermal conductivity and diffusivity of rocks, radio-elemental (U, Th and K) analysis of rocks and heat production estimates, various corrections applied to temperature, rock's thermal property and heat flow datasets.
Other provisional topics included:
Unfortunately both proposed conveners were not able to attend the IASPEI Assembly and the session was convened and chaired by Vladimir Cermak (firstname.lastname@example.org). Originally six oral presentations were scheduled with one poster which was delivered on Wednesday. Two presentations by Yu.Popov et al., and by S.Roy were canceled.
The actually realized programme thus covered the following presentations:
Two first presentations (Cermak, Demezhko) focused on very tiny temperature time variations in boreholes observed in various geological localities around the world, namely Kamchatka, Czech Republic and Mexico, resp. Kunashir Island, Russia). Recorded data are obtained by modern high-sensitive data loggers enabling to detect temperature changes of thousandths to first hundredth degree. The observations were discussed and explained as the result a product of convection of borehole fluid, as well as a potential response to tidal modulation. It was demonstrated that a fluid in a borehole, subject to thermal gradient, is stable as far as the gradient remains below certain critical value. At higher Rayleigh numbers the periodic character of oscillations characteristic for “quiescent” regime is superseded by stochastic features. This “oscillatory” convection occurs due to instability of the horizontal boundary layers.
Paper presented by Jones focused on the increasingly important application of geothermal studies is in the field of mine ventilation and refrigeration engineering.
As mining operations approach greater depths and as in some mines in South Africa the virgin strata temperature exceeds 70 °C, the problem of ventilation and prediction of the heat load on underground workings becomes important not only for worker safety and hygiene but also for mine feasibility planning . Author presented case studies comparing the virgin rock temperature data and rock property data from different mining areas as well as detailed measurements on backfill from a deep gold mine.
The statistical information on thermal conductivity of rocks is important to design a geothermal heat pump system because thermal conductivity of the ground can provide reliable system design. The Korean paper, presented by B.O.Shim, analyzed numerous measured thermal conductivities of rock samples collected over the whole country. The whole data set was divided into igneous, metamorphic and sedimentary rock types.
The only poster presentation belonging to the H2 session was presented by Demezhko. He analyzed borehole temperature log (Kunashir island), converted it to the ground surface temperature and correlated with the oak’s ring width index series. Prior to paleoclimatic interpretation temperature-depth profile was topographically corrected and the local anomaly, induced by water flow, was eliminated. The ground surface temperature revealed a cold period with mean annual conditions of about 3˚C from AD1600 to the second half of 19th century, which coincides with the Little Ice Age. The subsequent warming resulted in the increase of mean annual temperature up to more than 6˚C by the end of 20th century.
The general audience during the whole session varied at about 20 listeners. Each presentation was followed by brief discussion consisting of two to three questions or remarks. After the session an unofficial discussion continued.
Cape Town, January 2009; Report prepared by Vladimir Cermak