Geothermal image gallery

Did you know?

• Borehole setup

  The Geothermal system consists of a series of 44 wells, drilled down into the sand, gravel, glacial till and finally into shale bedrock beneath the parking lot. Prior to installation of the entire field of wells, a test hole was bored, and a thermal conductivity test was performed. Thermal conductivity refers to the rate at which the borehole and geologic formations transfer heat.

  
  

  This test hole showed that the upper 12 meters of the sand layer is unsaturated, which means that it does not hold or transfer as thermal energy as well as if it were saturated. The water table starts 32 meters below ground level and would be considered part of a high yield aquifer.

  To test the conductivity of the ground, and thus its suitability for a geothermal system, a 32mm diameter high density polyethylene (HDPE) u-loop pipe was installed in the ground. This pipe is CSA certified for use in geothermal systems, and is grouted in place for stability.

  The test showed that the bedrock improved the thermal conductivity of the site, because the shale has higher conductivity than the overburden.

• Geothermal vs. traditional heating systems

  To understand why a Geothermal system is more efficient than traditional heating with natural gas or electricity, compare how much energy is required to achieve one unit of thermal energy for use in heating.

  A high efficiency, natural gas condensing boiler will convert one unit of thermal energy potential in gas into about 0.95 units of usable thermal energy, with 5% lost as heat in the exhaust or condensate. A Geothermal heat pump system will use one unit of electricity to move approximately 3.5 units of heat from the ground loops into the building. This is obviously quite the “energy return”.

  Free cooling mode, described above, works very well at the ERC because of its Thermal Mass, and large ceiling areas used as heat transfer surfaces. The ground temperature in the summer months remains low enough to directly cool the ceiling slabs without the use of refrigeration equipment. We can cool the building with only 18 horsepower in pumping energy. Sometimes the refrigeration equipment is needed, particularly if humidity levels are high, and the ventilation air must be dehumidified to ensure comfortable air conditions within the building spaces.

  To date, the heat removed from the Geothermal system in the winter has been balanced by the heat removed from the building in the summer. The automation system is programmed to vary how it uses the field to maintain this annual balance.