Energy Piles for commercial Applications
What is an Energy Pile?
An Energy Pile allows for the dual use of building foundation piles by providing essential structural support and also as a way to contribute to the renewable heating, cooling and hot water production of a building.
How is an Energy Pile constructed and installed?
An Energy pile is somewhat similar to a traditional building pile used in commercial buildings in that a steel cage is constructed out of reinforced bar and lowered into a hole bored in the ground. The difference being that an energy pile also includes the installation of polyethylene or PEX-a pipe either as a single loop or as multiples depending on the size of the pile and the thermal capacity of the surrounding ground. The pipework is generally tied to the internal structure of the mesh after the pile is constructed and then pressure tested before it is lowered into its final position in the hole and concrete is applied.
The loops in the energy piles are joined in a reverse return configuration like a vertical ground loop installation and taken back to the plant where they are linked to geoexchange heat pumps.
Why use energy piles?
Geoexchange in itself is an efficient solution to provide heating, cooling, hot water or pool heating in commercial applications. As a large amount of commercial projects have a limited amount of free ground space they tend to move towards using vertical loops for a geoexchange system. Whilst still offering great feasibility in a project the cost of vertical loops can add a considerably cost to a project so we need to look at ways of reducing the capital expense of the system. This is where Energy Piles can come into play, if a building is already includes a pile system for it’s foundations the added cost of supplying and installing the loop pipework would be a minimal extra cost to the project and therefore reduce the capital cost of an efficient geoexchange system.
Basic overview of Energy Pile
Pipework is inserted into the structure of the pile prior to it's installation in to the bore hole. It is then filled with concrete.
Where can Energy Piles be utilised?
If a building is to use piles in it’s construction and has a heating or cooling load then the feasibility of using this option can be explored. Such things like the spacing, depth and circumference of piles, the thermal conductivity of the ground around the pile and the number of piles are all factors that need to be assessed as well as the loads of heating and cooling for the building. If there is not enough piles within a build to cover the required load then a hybrid system could be utilised that uses a additional capacity via vertical or horizontal ground loops or dry coolers/ cooling towers.