Case
Optimizing Geothermal Efficiency with Grundfos MAGNA3 Circulators
The Situation
In 2024, Energy Environmental Corp installed MAGNA3 circulators at Hill Country Hacienda, a 30,000-square-foot private residence in Kerrville, Texas. The property utilizes geothermal heat pumps for radiant floor heating and cooling, with supplemental air cooling provided by a 40-ton vertical ground heat exchanger (GHEX). To achieve higher efficiency and reduce maintenance, Energy Environmental Corp and Geo-Flo Corporation professionals upgraded the heat pumps in 2024.
The Grundfos Solution
The home’s original pumping configuration was upgraded to two Grundfos MAGNA3 40-180 pumps that circulate fluids to the GHEX using differential temperature control, optimizing capacity and energy efficiency. Three MAGNA3 80-100 circulators serve the campus distribution, each set on constant pressure to regulate steady water pressure and control the flow to the heat pumps. The project also featured three Grundfos ALPHA2 15-55 HWR-D pumps to deliver instant hot water, contributing to further energy savings.
According to system designer Al Wallace, “System controls are greatly simplified! When set on differential temperature or constant pressure, MAGNA3’s need only one closed contact when any heat pump calls to deliver GHEX consistently and efficiently.”
When asked about his choice of Grundfos pumps for these installations, Wallace cited superior technology, energy efficiency, and ease of installation of Grundfos MAGNA3 pumps. In addition, Grundfos's commitment to customer service further solidified Energy Environmental Corp's decision.
Wallace emphasized the importance of using highly efficient pumps for optimal system performance, noting the trend toward using larger pumps with VFDs for more extensive applications. By designing systems that utilize multiple large ECM circulators instead of fewer larger pumps with VFDs, he believes the industry can achieve greater redundancy and optimization of pump performance.
The Result
The upgraded system yielded three significant advantages: reliable performance, energy savings, and easy installation. The upgraded system provided twice the pumping capacity at a one-third reduction in energy consumption compared to the original fixed-speed pumps. Wallace commented that using variable-speed pumping with variable-speed heat pumps made the source (ground loop) pumping into a fully variablespeed system, reducing energy consumption by nearly 50%.
“Fixed speed pumping constitutes 17% of the energy use of a geothermal system; therefore, using variable speed circulators reduces energy use by 50% while lowering the amount of heat injected into the system by over-pumping. While pumping energy may be desired for heatingdominated climates, commercial buildings tend to be cooling-dominated,” he stated. “Reducing pumping energy reduces ground heat exchanger sizing for cooling-dominated applications, which contributes to lower capital, operating costs, and maintenance costs.”
System controls are greatly simplified! When set on differential temperature or constant pressure, MAGNA3’s need only one closed contact when any heat pump calls to deliver GHEX consistently and efficiently.
Geo-Flo Corporation supplied the MAGNA3 pump flow centers and a hydraulic separator, streamlining the installation process and enabling two technicians to complete the entire system setup within 10 days. The partnership between the two companies showcases geothermal technology as a sustainable, efficient solution for residential heating and cooling.
The success of this innovative installation serves as a testament to the efficacy and versatility of Grundfos MAGNA3 circulators. The project’s outcome demonstrates the potential of innovative geothermal solutions to optimize energy savings and enhance system performance, paving the way for a more sustainable future in residential heating and cooling systems.