If sufficient land area suitable for drilling or trenching is available, horizontal loops may be the most economic.
A horizontal system will use a number of horizontal trenches. Piping system designs range from a single pip, to multiple pipes arranged vertically in a narrow trench to multiple pipes in a wider trench.
The ground heat exchanger may be either series or parallel piping. Each has both advantages and disadvantages.
- Single flow path and pipe size
- Higher thermal performance per foot of pipe, since a larger diameter pipe is required.
- Larger water or antifreeze volume of larger pipe
- Higher price per foot of piping material
- Increased installed labor cost
- Limited length due to fluid pressure drop and pumping costs
Fabricated from smaller diameter pipe, which is generally less costly, special care must be taken in flushing to get all the air out of the piping loop.