There are variation in horizontal loops which is referred as "Slinky". A slinky closed loop field is also used in horizontal closed field. Slinky can be laid down in two ways, Depending on the width of the trench that holds the pipe coils. The horizontal slinky layout consist of piping unrolled in overlapping circular loops which are laid at flat in trenches of approximately the same width as the coils diameters. It is typically used to 3 to 6 feet wide. In vertical slinky layout, coils used to stand upright in narrow trenches which are deep enough to accommodate the coil diameter and which can overburden sufficient so that the tops of the coils do not experience high temperature.

Here the pipes overlay each other. The better and easy way to imagine slinky filed is to imagine holding a slinky on the top and bottom with your hands and then move your hands in opposite directions. A slinky close loop can be used if there is not adequate room for true horizontal system. It allows for easy installation.

Slinky systems typically require 700 to 900 feet of piping per system ton, it depends on soil properties and depth of burial. It depends on the coil pitch which overlaps between adjacent spirals, slinky installation can accommodate 80 to 120 feet of piping for every 12 feet of trench. Slinky loop require five time less area than straight horizontal loop system. It requires area in between 500 to 800 square feet per ton.

Slinky coils get more damage by backfill. If we didn't take care of backfill it will result in high damage of slinky loop. Particularly if the backfill is material has a large rock or clouds in it. All these used to happen because air is a poor heat conductor, which voids greatly reduce the loop's ability to exchange heat with the surrounding soil.

A typical geoexcahange slinky loop consists of four or five trenches separated by 10 to 15 feet. It is laid with 600 feet of coil. It can be installed with four experience people. The average work time to install a geoexchange slinky loop is about an hour. It takes 20 minute per ton of coil. After all cost are counted, it finally makes to $800 per geoexchange ton.

Closed Horizontal Slinky Loop, 10T System
Geothermal loop field installed
500 sq ft
New construction
2 x 5T Geothermal Hydronic
Heat Pump System
Radiant Heat floors on 2 levels
3 Zone hydro-air distributed cooling system

Recommended Reading:

1. Horizontal Closed Loop - This loop is composed of pipes that run horizontally in the ground. A long trench being dug which is deeper...
2. Closed Field Loop - Geothermal heating process is widely used from Roman times as it is way of heating buildings. By utilizing sources of...
3. Horizontal Installed Loop Field - Horizontal installed loop field is a type of loop field used in Geothermal heating systems. This heating system runs on...
4. Closed Pond Loop - A closed pond loop is not as common. It has been becoming increasingly popular. A pond loop is formed by...
5. Vertically Closed Loop Field - Geothermal heat pumps employ one of the following types of external loop: * Open Loop * Closed Vertical Loop *...