Low-temperature geothermal systems consist of closed-loop boreholes with depths ranging from 100 to 250 meters, including heat pumps and indoor heating units such as ceiling panels or fan coil units. The geothermal boreholes comprise pipes installed in the ground using specialized drilling equipment, connected together to form a common geothermal collector.
For example, a 2,000 square meter building would require 2,000 linear meters of boreholes, divided into 20 boreholes at 100 meters depth each. At a depth of 100 meters, the ground temperature remains constant, typically between 12 and 15 degrees Celsius, which is converted into heating and cooling by heat pumps. The circulating fluid in the closed-loop geothermal system is a mixture of water and a minimal amount of antifreeze. These systems do not utilize groundwater.
When cooling the building, the ground temperature of 12 to 15 degrees Celsius is sufficient to provide air conditioning in “free cooling” mode—also known as passive or cost-free cooling—when ceiling panels are included in the system design.
