Although EnergySmart Alternatives has experience installing horizontal ground loops, most of our installations are vertical closed loop systems.
There is a common misconception that horizontal trenching is always the cheapest method of installation. In New England, where bedrock is close to the ground surface and there are many rocks (and boulders!), trenching can be difficult and unpredictable. In ideal situations, an experienced excavator can trench 100 to 150 feet per day. The time required to excavate can easily be doubled when difficult conditions arise. If a lot of rocks are present, it may be necessary to line the trench with sand or clean soil in order to protect the pipe from abrasion. Although we take great care to compact the soil after back-filling the trenches, there can be significant settling of the area over time.
Vertical drilling is very predictable. Bedrock (ledge) is not a problem – it is actually preferable for its heat transfer properties. The drill rig is the same equipment that is utilized to install drinking water or irrigation wells. An experienced driller will be able to drill 200 to 300 feet per day. The borings are finished three to four feet below grade so there is no evidence of the boring once the area is back-filled. There is no visible well head. Our on-line photo albums have a lot of great pictures showing the drilling equipment used for vertical drilling.
To see how the pipe is installed into a vertical boring, please see our video from a geothermal installation in Winchester, MA.