Status: Ongoing
In the Yukon territory, there is a gap between the seasonal availability of existing hydro and solar energy in summer and the energy needs for heat in the winter. This gap is being filled through the direct use of diesel and propane for heat, and diesel and liquefied natural gas for electricity generation. Heating is the source of 18% of the Yukon territory’s greenhouse gas (GHG) emissions. Geothermal is a promising source of renewable energy that can address heating needs for Northern communities while reducing GHG emissions. Ground source heat pumps (GSHPs) transport geothermal energy from the subsurface into buildings. They are more than 100% efficient at transporting heat energy using electricity, and provide a low and stable cost of energy over the long term (~25 years) while reducing emissions. The cost efficiency of GSHPs is closely related to the thermal conductivity of the geological formations of the site. The objective of this proposal is to conduct two thermal response tests (TRTs) in existing groundwater monitoring wells, one well hosted in bedrock and one hosted in unconsolidated geologic materials (e.g. sand and gravel). The information collected will be used to understand and compare the thermal properties of these two different geologies. We can then begin to assess the viability of GSHP technology for different locations in the Whitehorse area. Using existing monitoring wells will lower the costs of the tests. Preliminary results of this study will help to identify target geological formations for GSHPs and identify key areas for further investigation.
Goals of the project
1) Determine the specific thermal conductivity of an unconsolidated aquifer vs a bedrock aquifer to make a preliminary observation about potential geological targets for the development of GSHP systems.
2) Test the efficacy of a remote or solar energy system. The test requires a heating load of 1.2 kW over 36 hours. This requirement will be met through a remote solar energy system. This reduces the need for a gas generator (one will be on-site as a backup) and reduces the GHG emissions of the project.
3) Use a cost-effective experimental design. The methodology proposed uses lower-cost equipment than the standard TRT kits and was developed by Dr. Jasmin Raymond, a leading geothermal researcher from the Institut National de la Recherche Scientifique (INRS). Jasmin is in Whitehorse until the end of June and is the technical expert guiding this project. Mary Samolczyk, Yukon University faculty member, will provide support of project oversight and local hydrogeological expertise. A secondary goal is to build capacity for Yukon University to conduct thermal response tests at other sites in the future using this equipment.
Methods
TRTs involve using a heat source and temperature data loggers to assess the in-situ thermal conductivity of a hydrogeological formation. These tests are critical to appropriately size the heat exchanger and number of boreholes needed to meet a building’s energy needs. I propose utilizing a 3 kW solar energy system to supply the energy needed for the heating load to eliminate carbon emissions for the test. A heating cable will be lowered to the target depth within an existing water monitoring well with an adjacent temperature data logger installed as detailed by Raymond (2018). This methodology is simpler than the standard TRT, and requires less expensive equipment, but will be adequate to assess thermal conductivity of the target formations. Heat will be applied for a minimum of 36 hours and the temperature response of the formation throughout the test duration and the time to return to the base temperature can then be measured and analyzed.
University Resources
Mary Samolczyk will be the faculty supervisor of the project and provide local hydrogeology expertise. We may use some of the hydrogeology equipment such as the water level meter. I do not anticipate any other University resources will be required.
This equipment (heating cable, data loggers, connection box and accessories) will be retained by the University. The tests it enables are necessary to determine the economic feasibility of GSHP in the Yukon. We expect interest to grow over time with government priorities to pursue low-carbon heating technologies. This equipment will be available for community partners in the development of pilot projects, for example, the Northern Community Land Trust’s new 32-unit permanently affordable development in Whistlebend. It will also be available for future research, for example, Sarah Newton intends to pursue a Master’s degree in geothermal/GSHPs and this equipment may be used locally for such projects.
Partners and funders
YukonU Scholarly Activity