Uniform Geothermal Gradient
Location: Qiongdongnan and Pearl River Mouth Basins, ChinaYuan et al. used a uniform geothermal gradient to find temperature distribution. Oil and gas exploration surveys measure the thermal conductivity, radioactive heat production, geothermal gradient values and heat flow values.
Location: Khachmaz and Sabir-Oba, AzerbaijanNabiye et al. measured temperature and pressure to calculate the following properties in characterizing geothermal resources:
- From temperature (T) and pressure (P):
- Empirical correlation for density (ρ),
- Isothermal compressibility (βT),
- Isobaric thermal expansibility (βP), and
- Difference in isobaric and isochoric heat capacities (CP and CV).
Open-Loop Well-Doublet SchemesBanks assessed thermal plume effects from open-loop well-doublets. Well-doublets abstract water from the ground, perform heat transfer and injects used water into the ground. This temperature difference in water affects sensitive species and pollution to downstream users. Backwash injected water may mix with cold abstracted water over time to render the system useless. The open-loop system is an improvement on the original idea to make the scheme economically viable.
Location: Cape Verde, West AfricaHeilweil, Solomon, Gingerich, and Verstraeten investigated groundwater systems using stable radioactive isotopes. The water source was rain at high elevation. Geothermal activity did not affect the groundwater. Seven sites had water residence time for over half a century, such as the Ribeira Faj Basin at So Nicolau Island. Mosteiro Basin at Fogo Island and Ribeira Paul Basin at Santo Anto Island were found to be at risk from surface contamination and salination.
The Urban Heat Island Effect
Location: Istanbul, TurkeyUrbanization causes elevated groundwater temperature. The sources could be heat loss and energy absorbed by developed land. Yalcin and Yetemen found South Istanbul groundwater temperature 3.5oC higher than North Istanbul. They suggested geothermal energy using heat pump for recovery is one of the alternative to fossil fuel energy.
Location: Yellowstone National ParkPlaner-Friedrich, Fisher, Hollibaugh, Suss, and Wallschlager found microorganisms related to Thermocrinis rubber breaks down trithioarsenate to arsenate in the alkaline, sufide-containing geothermal springs. This microbial catalysis is 40-500 times faster than laboratory oxidation. This natural phenomenon could be used to develop arsenic remediation.
ReferencesYuan, Y., Zhu, W.L., Mi, L.J., Zhang, G.C., Hu, S.B. & He, L.J. (2009). "Uniform geothermal gradient" and heat flow in the Qiongdongnan and Pearl River Mouth Basins of the South China Sea. Marine and Petroleum Geology, 26(7), 1152-1162. DOI:10.1016/j.marpetgeo.2008.08.008Nabiyev, N.D., Bashirov, M.M., Safarov, J.T., Shahverdiyev, A.N. & Hassel, E.P. (2009). Thermodynamic properties of the geothermal resources (Khachmaz and Sabir-Oba) of Azerbaijan. Journal of Chemical and Engineering Data, 54(6), 1799-1806. DOI:10.1021/je800840mBanks, D. (2009). Thermogeological assessment of open-loop well-doublet schemes: A review and synthesis of analytical approaches. Hydrogeology Journal, 17(5), 1149-1155. DOI:10.1007/s10040-008-0427-6Heilweil, V.M., Solomon, D.K., Gingerich, S.B. & Verstraeten, I.M. (2009). Oxygen, hydrogen and helium isotopes for investigating groundwater systems of the Cape Verde Islands, West Africa. Hydrogeology Journal 17(5) 1157-1174. DOI:10.1007/s10040-009-0434-2Yalcin, T. & Yetemen, O. (2009). Local warming of groundwaters caused by the urban heat island effect in Istanbul, Turkey. Hydrogeology Journal, 17(5), 1247-1255. DOI: 10.1007/s10040-009-0474-7Planer-Friedrich, B., Fisher, J.C., Hollibaugh, J.T., Suss, E. & Wallschlager, D. (2009). Oxidative transformation of trithioarsenate along alkaline geothermal drainages: Abiotic versus microbially mediate processes. Geomicrobiology Journal, 26(5), 339-350. DOI:10.1080/01490450902755364
Inspiration: Hot Springs Around the World from gosmiley.com
- Empirical correlation for density (ρ),