The Solutions

Before initiating the geothermal conversion project, MMH had explored multiple options to replace the facility’s existing chiller, including air- and water-cooled chiller options. However, they ultimately decided to implement a geothermal central plant due to its superior energy performance and long-term value. CMTA collaborated closely with MMH to evaluate costs and scheduling, demonstrating the feasibility of integrating the new geothermal system into their existing infrastructure.

To maximize the Outpatient & Cancer Center’s energy efficiency, CMTA conducted an in-depth analysis of the central plant’s existing systems. The evaluation revealed the systems were oversized for the facility, consuming excess energy and operating at an unnecessarily low leaving air temperature, which strained the chiller and increased reheat demand. Additionally, the constant-volume pumping strategy combined with the use of 30% glycol in the outdoor chiller system reduced heat transfer efficiency, further escalating energy consumption. Leveraging this insight, the design team “right-sized” the new systems to meet the facility’s actual needs, significantly reducing overall energy consumption. This included removing the 210-ton oversized air-cooled chiller and installing 7.73 miles of geothermal linear piping with its respective mechanical systems. Three 60-ton, 6-pipe heat recovery chillers were also installed, which not only minimize boiler usage during below-freezing temperatures but also efficiently heat the facility using heat pump modules, even when outside air temperatures drop as low as 20°F.

These upgrades drastically reduced the facility’s Energy Use Intensity (EUI) to 140 kBtu/ft²/yr—a 40% reduction from the facility’s benchmark of 233 EUI. As a result, the new cancer center has achieved an 80% reduction in natural gas consumption and gas usage costs. MMH also received two utility rebates for the facility’s energy-efficient design—one totaling $4,600 for adding a variable frequency drive (VFD) to the chilled water pump and another $14,085 rebate for installing a more efficient chiller. Additionally, the project secured $413,046.12, or 40% of the total cost, in federal clean energy tax credits for the installation of the geothermal system, made possible by leveraging a domestic content bonus credit. Combined with operational savings, these incentives paved the way for the project budget to be expanded from $500,000 to $1.1 million, achieving a remarkable four-to-five-year expected payback period.