Evaluating the geothermal heat pump potential from a thermostratigraphic assessment of rock samples in the St. Lawrence Lowlands, Canada
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- 作者：Jasmin Raymond ; Cédric Sirois ; Maher Nasr ; Michel Malo
- 关键词：Geothermal ; Heat pump ; Thermostratigraphy ; Thermal conductivity ; Sedimentary basin ; St. Lawrence Lowlands ; Canada
- 刊名：Environmental Earth Sciences
- 出版年：2017
- 出版时间：January 2017
- 年：2017
- 卷：76
- 期：2
- 全文大小：
- 刊物类别：Earth and Environmental Science
- 刊物主题：Geology; Hydrology/Water Resources; Geochemistry; Environmental Science and Engineering; Terrestrial Pollution; Biogeosciences;
- 出版者：Springer Berlin Heidelberg
- ISSN：1866-6299
- 卷排序：76
文摘
The installation cost and the performance of geothermal heat pump systems are influenced by the thermal state and properties of the subsurface. The ground ability to transfer heat described by thermal conductivity is a dominant factor affecting the favorability of closed-loop ground heat exchangers installed in vertical boreholes. A study that aimed at evaluating the geothermal heat pump potential by mapping the thermal conductivity of rock sequences was, therefore, performed for the St. Lawrence Lowlands sedimentary basin in Canada. Thermal conductivity was measured in the laboratory on rock samples collected in outcrops and used to complete design calculations of a geothermal system with a single borehole. Results allowed the definition of thermostratigraphic units that can be linked to depositional environments. Basal quartz-rich sandstones formed in a rift environment show a high geothermal potential. Overlying dolomites, argillaceous limestones and shales deposited in a passive margin evolving to a foreland basin exhibit a transition toward the top from high to low geothermal potential. Upper turbidites and molasses have a moderate geothermal potential. The thermal conductivity of the thermostratigraphic units is dominantly influenced by the mineralogy of the sedimentary rocks. Understanding their origin is a key to improve geothermal resource assessment and system design to anticipate new installations in the area.