Geothermal Loop Configurations

The heart of any geothermal system is its underground loop.

There are two general types of geothermal loop systems: closed and open. Open-loop systems in Baltimore, MD tend to be more problematic due to poor groundwater quality. That’s why we typically recommend closed-loop systems.

All loop systems are created equal, and no one geothermal loop is better than another if it gives you the required heat transfer in the ground.

There are several installation methods to achieve a closed loop, and many opinions about which is best. Whether they are horizontal, vertical, slinky, or straight pipe, these loops are equal because they are designed to be equal.

At Ground Loop Heating and Air Conditioning, we believe the best loop is the loop that fits your needs and geothermal budget.

Closed Loops

We recommend closed-loop systems in Maryland and neighboring states. In this system, water or an eco-friendly antifreeze solution circulates through a buried pipe. The length of the pipe depends on several factors, including the ground’s thermal conductivity, temperature, and moisture levels.

When installed correctly, closed-loop systems are efficient, economical, and reliable.

Open Loops

In an open-loop system, groundwater from an aquifer is drawn through a well. The water passes through the heat pump’s heat exchanger and eventually discharges to the aquifer through a second well.

For an effective heat exchange, two to three gallons per minute per ton of capacity typically is necessary. Because groundwater temperature is nearly constant throughout the year, open-loop systems are popular in areas where they are allowed and have been used successfully for decades.

However, there are several challenges associated with open-loop systems.

The chemical conditions of some local groundwater sources can foul the heat pump’s heat exchanger. In this situation, extra precautions may be necessary.

Local officials must approve water use and discharge methods to ensure compliance with environmental regulations and concerns. It is rarely acceptable, for example, to discharge wastewater to a sanitary sewer system.

Horizontal Loops

Horizontal geothermal loops are usually the most cost-effective option for small geothermal installations with enough land to accommodate them. In this system, up to six pipes are buried in trenches in parallel connections, with at least one foot between pipes and 10 to 15 inches between each trench. Slinky-style loops are also commonly found in horizontal loops.

Vertical Loops

Vertical, closed loops are preferred in many situations because they require little space. Ground Loop Heating and Air Conditioning has even installed vertical loops directly in a driveway on 1/8th of an acre. For example, many schools and commercial buildings rely on vertical loops because a horizontal loop would require too much space.

Because of their small layout, vertical loops are the most common loop configuration. Depending on the ground conditions, the loop generally is installed from 200 to 400 feet deep.

There are two styles of vertical drilling used in our area. Air rotary drilling utilizes high-pressure air to drill through rock structures and is commonly used in areas west of Route 95. Mud rotary drilling uses recirculated high-pressure water to bore through mud, sand, clay, and gravel and is generally used east of Route 95.

Pond Loops

Pond loops are a closed-loop system that uses an existing pond or stream. If the body of water is deep enough and has enough flow, then a system of closed-loop coils can be placed on the bottom of the pond. A pump moves the liquid inside the loop, just as it would in a conventional closed-loop ground system. Pond loops have not been shown to damage nearby aquatic systems, and they are an economical option when the conditions are suitable.

Which Geothermal Loop Works Best?

At Ground Loop Heating and Air Conditioning, we will design a loop system that works best for your Baltimore, MD home and budget. Let our experts configure a ground loop that fulfills your heating and cooling needs.

For more information about geothermal systems, call us at 410-836-1706 or request service online.