The Closed-Loop Geothermal System: Making It Nice and Simple

A closed-loop geothermal system can offer extremely high levels of heating and cooling efficiency delivered at a price that fuel-based or electrical systems cannot match. When planning and designing your geothermal installation, it’s best to keep the system as simple as possible to get the best performance with the least amount of expense and trouble.

The Basic Operation of a Closed-Loop Geothermal System

Geothermal systems look complicated, but their operation is based on a relatively simple process of heat capture and release. A closed-loop system requires a series of pipes, called the loop, installed at a depth in the ground or in a body of water where the temperature stays nearly the same all year long. An antifreeze/water mixture or less commonly, refrigerant circulates through the loop, traveling from the outdoor pipes to the inside of your building and back again. When providing cooling, the fluid captures heat from inside the structure and releases it from the ground loop into the ground. When heating, the reverse occurs, with heat being absorbed from the soil or water around the ground loop and released inside your building.

Horizontal Versus Vertical Ground Loops

Ground loops are installed in one of two standard configurations, based on factors such as the amount of ground space available and the quality of the soil where the loop is being installed.

• Horizontal: A horizontal closed-loop geothermal system is best used when there is a substantial amount of available land for installing the loop. The loop is placed on a flat plane in several trenches dug about four to six feet deep into several hundred square feet of open land. The loop pipes may also be stacked, providing even more contact with the soil where heat transfer will take place.
• Vertical: Vertical closed-loop systems are used in areas where there is not a lot of flat space for loop installation, such as urban areas. The ground loop is placed in a series of holes drilled up to 600 feet deep and about 20 feet apart. Vertical systems are also used in areas where the soil does not allow a horizontal installation, such as where the soil is rocky or thin or where there are layers of solid rock a short distance below the topsoil.

Simplifying the System

The best results will be achieved from a closed-loop geothermal system that is kept as simple as possible, with common types of controls and high-efficiency components.

• Loop type: A unitary loop is the simplest style of closed loop. It consists of an individual heat pump combined with a circulator pump that cycles along with the compressor. The single ground loop is constructed with pipes most commonly made of high-density polyethelyne. A unitary loop is usually the easiest and least expensive type of loop to install. It can be serviced easily by trained technicians and works best for one- or two-story buildings.
• Packaged heat pumps: The system relies on a heat pump for heat capture and release, and in most cases, a standard packaged heat pump will be the simplest and most cost-effective choice. You can look for high-efficiency models that boost performance and reduce costs even further.
• Zoned controllers: A zoned heating and cooling configuration, using standard programmable thermostats, provides an easy and simplified way to distribute heating and cooling inside your building. The zoning system allows you to divide your indoor space into separate zones or areas that will receive heating and cooling. The programmable thermostats give you significant choices for system operation without the need for complicated controllers. These types of thermostats function well right out of the box and are relatively easy for trained technicians to install and calibrate.

Our goal is to help educate our customers about Plumbing, HVACR, Fire Protection and Alarm Systems in Mechanical, Commercial and Residential settings. For more information on how a closed-loop geothermal system can work for your commercial building, and to view projects we’ve worked on, visit our website!