page_title: Direct exchange geothermal heat pump
section_title: Applications
hierarchical_section_title: Direct exchange geothermal heat pump / Applications
caption_attribution_description: English: Terry Teate is photographer and owner of the drill.
context_page_description: A direct exchange geothermal heat pump is a type of geothermal heat pump in which refrigerant circulates through copper tubing placed in the ground. It is a closed-loop, refrigerant-based geothermal system.
  Direct exchange geothermal heat pumps function similarly to air source heat pumps, according to the principles of vapor compression refrigeration, except they take advantage of the relatively constant ground temperatures, which are less variable than outdoor air temperatures. Ground temperature is cooler than the outdoor air temperature in summer – making for a better heat sink – and warmer in the winter – making for a better heat source. Direct exchange geothermal heat pumps are therefore more efficient than air source heat pumps. They are also quieter, more durable and require less maintenance since they don’t have any outdoor fan or outdoor coil. Furthermore, the uniformity of the underground temperature compared to the outdoor air translates into less stress on the systems.
  In direct exchange systems, the refrigerant exchanges heat directly with the soil through the copper tubing.
context_section_description: Direct exchange systems are rather simple refrigerant-based systems and operate without requiring anti-freezing agents, system flushing, circulating pump, water well drilling or plumbing.
  Depending on the models, they can provide space heating, space cooling, domestic water heating as well as radiant floor hydronic heating and chilled water cooling.
  Direct exchange geothermal systems are the least invasive geothermal systems and feature small earth loop size. Because of that, they can be installed in relatively small areas and in relatively shallow soil - typical loop depth does not exceed 100 linear feet.
  Since the length of the ground loop system is minimized, DX systems require smaller drill rigs - in comparison with water well rigs - which can get into smaller spaces and yards. This provides a greater flexibility of installation and makes it an available option in more areas and for more properties.
  
  The compactness of the earth loop systems, which require less drilling and smaller borehole, makes up for a simpler system that is cheaper and quicker to install.
  The relative simplicity of refrigerant-based systems – relying on a one-step heat exchange process – translates not only into a simpler and less expensive installation but also into less maintenance as well: unlike water-based systems, they do not require maintenance to top up water and glycol levels.
caption: Typical drill rig for DX installation, length 8 ft
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