With a growing trend toward sustainability, Schmidt Associates has received an increasing number of inquiries about geothermal heating systems. We are also designing geothermal systems for a variety of projects. This is the third in a series explaining the technology.

Design procedure is critical when you are selecting a geothermal system to provide heating, cooling, and hot water for homes and commercial buildings. A poorly designed system will adversely affect the whole performance.

The first step is a detailed, accurate energy model using hourly weather data to determine the building’s heating and cooling loads. To optimize building loads to work on a sustainable basis with the ground heat exchanger (GHX), the owner/design team must work together to develop a GHX model that will perform predictably.  During the design process, the team will analyze:

—•   Soil thermal properties (test boring)
•   Borehole configuration (spacing and depth)
—•   Ground loop fluid properties (glycol? what type?)
—•   Borehole thermal resistance (test boring)

A preliminary energy model helps determine the cost effectiveness of architectural design and projects energy cost savings. It will also help determine what type of heat pump is best for the building conditions.

Look for our next blog in this series regarding how the geothermal system selection impacts the building design.