How Geothermal Heating and Cooling Works

Geothermal System

Geothermal System

Geothermal heating and cooling is the most efficient comfort available thanks to the nearly constant temperature of the Earth a few feet below the surface. Tubing buried in the ground circulates fluid that carries this warmth to the geothermal unit inside your building (called a heat pump). The unit takes heat from the liquid, intensifies it using compression principles, and transfers heat to the building as warm air in the winter. During the summer, the system draws heat from your building and carries it, using the fluid in the tubing, back to the ground.

Geothermal Heat Pump

Geothermal Heat Pump

Geothermal Source Heat Pumps are a cost effective, energy efficient, and environmentally friendly way of heating and cooling buildings. Heat Pumps reliably deliver quality air-conditioning and heating, on demand, in every season. Heat Pumps are appropriate for new construction as well as retrofits of older buildings. Their flexible design requirements make them a good choice for schools, high-rises, government buildings, apartments, and restaurants–almost any commercial property. Lower operating and maintenance costs, durability, and energy conservation make Ground Source Heat Pumps the smart choice for commercial applications.

Geothermal and Ground Source Heat Pumps offer great benefits:

  • Simultaneously heat & cool different parts of the same building
  • Significantly less noise compared to conventional system–users do not know when the system is operating
  • Take up less mechanical room space allowing better use of building space
  • Can eliminate outside equipment so weather does not increase deterioration
  • HDPE Pipes have 50-year manufacturers warrenty and an estimated 100 year life expectancy


Ground Loop Options

Types of closed loop systems

Geothermal Loop Types

Wellfield Loop Types

A closed loop system means the same fluid circulates in tubing over and over again in a sealed system. This pipe can be installed in a trench (straight or slinky formation), a pond or holes drilled vertically.

Vertical is the most common in commercial applications because it requires less physical land.




Vertical Loops

Geothermal Vertical Loops Vertical loops are the most common in commercial installations. If the land area available is limited, a vertical loop may be installed for the geothermal piping. Vertical installations might also be used where the land is too rocky for trenching, for existing buildings, and for large commercial or educational facilities.

To install a vertical loop, a contractor will bore holes into the ground. Long, hairpin-shaped loops of pipe are then inserted. The hole is backfilled, plugged or grouted, and the pipes are connected to headers in a trench leading back to the building. The drilling depth is determined by the lowest total cost based on the conditions at your location. A typical hole depth is 150 to 250 feet.

The objective of a vertical hole is to install a specific amount of pipe, not to reach a certain depth. For example, if 600 feet of pipe is required, three 200-foot holes may be drilled and be more cost-effective. Drilling for geothermal loops is much simpler than drilling to find well water. The hole is generally smaller, which reduces drilling time, and no casing is required because the hairpin-shaped loop is the casing.

Horizontal Loops

Geothermal Horizontal Loops If adequate land area without hard rock is available, a horizontal loop installation is usually the most economic. Horizontal loops are often used for newly constructed homes and commercial buildings.

A horizontal system uses a number of trenches. The piping can be configured in the trenches in several ways: a single pipe in a narrow, multiple pipes in a wider trench, or “slinky” pipe in laid in a trench.

The trenches are normally four feet deep or more, and vary in length depending on the number of pipes to be buried. One of the advantages of a horizontal loop system is being able to lay the trenches according to the size of the lot.

Pond Loops

Geothermal Pond Loops A large body of water such as a pond or lake can also be utilized to provide the heat source and heat sink for a geothermal application. Where an existing pond is used, the coils are floated into location and filled with fluid. As the coils are filled, they slowly sink to the bottom.

Ponds and lakes are excellent applications for geothermal systems since water provides superb heat transfer to or from the pipe. In colder climates where ice forms on the surface, the temperature at the bottom of the pond remains relatively constant and unfrozen providing an abundant supply of geothermal heat. Pond/lake loops are generally less expensive to install than horizontal or vertical loops since excavating requirements are minimized.