ANALYZING GEOTHERMAL PROPERTIES OF HARTFORD BASIN MATERIAL

Geothermal energy is a practical, clean, and sustainable energy option, but optimizing geothermal energy as it pertains to shallow geothermal systems, a.k.a. ground source heat pump (GSHP) systems, is an area in need of further research. This study presents research on the geophysical properties of glacial deposits and bedrock, materials into which a GSHP system would be installed. A key geophysical property for the design of an efficient GSHP system is thermal conductivity (K). Since K is tied directly to determining the length of ground exchange, it is also tied to system installation costs, an important consideration for GSHP proponents.

Samples of glacial deposits and bedrock were collected and analyzed from multiple locations within the Hartford area, during the summer and fall of 2014. All glacial deposits, with the exception of one location, were acquired using a hand auger. At two locations bedrock cores were collected by a commercial drilling team; one of these sites yielded split-spoon samples. Glacial materials ranged from cobbles to fines and represent glaciofluvial, glaciolacustrine, and glacial till deposits. The bedrock samples consisted of sandstone (Portland Formation), shale (unidentified) and basalt (Hampden and Holyoke Basalts).

In addition to measuring thermal conductivity, the samples were analyzed to determine grain size distribution, dry bulk density, moisture content, mineralogy, and organic content. Because these properties are sometimes poorly constrained for the glacial deposits and bedrock that typify regional geology, the data produced from this study will greatly facilitate the efficient design, installation, and operation of GSHP systems.