The Stockbridge-Munsee Health and Wellness Center, which may initially seem an unassuming facility to new visitors, carries out a critical mission and holds an important place in its community. Located in the rural town of Bowler, Wis., on the southwestern edge of the Menominee Indian Reservation, the more than 50-year-old clinic is a civic asset for the Stockbridge-Munsee Band of Mohican Indians.

The program began in the early 1970s as Volunteer Inter-Tribal Medicine, comprising a group of volunteer physicians who provided care and health screenings. The clinic started as a retrofitted mobile home and has since grown into a community wellness organization operated by and for the tribe. The facility includes a pharmacy, dental care, a radiology unit and countless other comprehensive community health services.

The existing clinic is a 30,170-square-foot building that opened in 2000. Served by an HVAC system nearing the end of its life, the existing infrastructure featured a conventional water-source heat pump for heating and cooling, an evaporative cooler, propane boilers and a propane-heated ventilation system. 

The evaporative cooler, which uses water as its working fluid, recirculates domestic water in the basin and sprays it over closed-loop coils of the hydronic cooling system to increase cooling capacity. To prevent chemical growth, systems like this one require extensive chemical treatment, and although the client had well-trained facilities personnel, it was decided that going in a new direction would be a more efficient and sustainable practice.

The Health and Wellness Center sought measures to achieve energy sovereignty for its organization. Its goal was to be far less reliant on propane to heat the facility and remove the need for regular chemical maintenance. To achieve this would require an entirely new HVAC system — one that could moderate the usage of natural resources and embody the community’s core beliefs. 

According to Shannon Holsey, president of the Stockbridge-Munsee Band of Mohican Indians, “We have always been good stewards of Mother Earth and finding collective ways to reduce our carbon footprint.” Now the question was: What might this low-impact system look like?

Exploring All Options

In 2012, Stockbridge-Munsee contacted Sustainable Engineering Group, now HGA, an integrated design and engineering firm, with specific goals and actionable change in mind. The organization’s leaders wished to shift the Health and Wellness Center toward renewable energy sources. More broadly, they also wished to become better stewards of their land but weren’t sure where or how to begin this journey.

HGA’s work began by conducting a feasibility study. Initiated in 2013, the study looked at various renewable options, including solar electric, solar thermal, biomass and geothermal. 

While all four of these systems were deemed viable, the geothermal system stuck out among the others because it could stand in as a direct replacement for the boilers and evaporative cooler in the existing system. Over the system’s life cycle, it would result in the lowest operating and maintenance costs relative to other renewable and dual-fuel systems. 

Perhaps the most impactful result is that this approach would empower the tribe and its health center to achieve greater energy independence and become less reliant on external resources.

Years later, with capital funding in place, HGA partnered with Ahern as the general contractor. The surface-level goal was to upgrade the health center’s HVAC infrastructure. The larger goal, however, was to instill in this design the tribe’s commitment to “preserve the natural resources in a pristine condition for the next seven generations.”

Getting to Work

Installing the geothermal bore field is invasive work. The bores are drilled with an 8-inch round drill bit to a depth of 300 feet. The soil is removed and replaced with a continuous tubing loop that will circulate geothermal water; then, the borehole is filled with grout to improve heat transfer. 

HGA’s engineering team and Ahern worked to ensure no adverse environmental impacts on the site’s ecology and hydrology. This work began with selecting the best site for the bore field. 

Four surrounding sites were identified and examined for potential development of a geothermal bore field. Unfortunately, tapping into the earth’s natural heating and cooling capacity is never simple, and this site was no different. 

Many factors were considered for each site and the best location was selected to minimize disruption to the site ecology. The site selected was an unused green space just off the road leading to the center; it was the right size to accommodate the number of boreholes and minimize the impact on the existing pond and surrounding forest. 

Initial testing was done by installing a single bore, which became part of the final system. The initial test drilling helped to determine the ideal depth for the bores. After installing a single bore, a test is run by circulating heated water through the bore tubing and calculating the rate at which heat is rejected into the ground. This test provides the thermal conductivity measurements used to determine the bore field size relative to the health center’s needs, square footage and daily usage. 

Upfront testing ensures that sizing is based on the actual site data and minimizes the risk of oversizing the bore field, which increases project costs, or undersizing the bore field, which leads to poor system performance. 

A total of 44 bores, each at 300 feet in depth, were needed for the bore field based on the site conductivity results. Each drilled bore was connected to horizontal mains buried below the ground. The mains route into a belowground vault with a manifold, allowing each set of bores to be balanced and isolated if needed. 

The lateral piping between the vault and the building was directionally bored. This process, also known as horizontal directional drilling, is a trenchless method of installing underground conduit or piping, in which a surface-launched drilling rig bores a prescribed path, and utilities are then laid. 

This approach is environmentally superior to conventional pipeline installations because it requires minimal backfilling and causes minimal disturbance to the site’s natural conditions. 

Phased Construction 

Construction of the project lasted for about a year and the clinic remained fully operational the entire time. “To help mitigate the impact of the clinic, we did this project in 10 phases throughout the course of the year,” explains Reid Simons, regional construction manager for Ahern. “This allowed the clinic to stay functional throughout construction.” 

This was paramount since Stockbridge-Munsee provides not only primary care, but also physical therapy, behavioral health care, a pharmacy and a host of other services critical to the small community. 

Keeping the doors open and operations unimpeded throughout construction was nonnegotiable. “The project took into account the importance of the clinic and the medical care for our community,” notes Andrew Miller, director of the Stockbridge-Munsee Health and Wellness Center.

The onset of COVID-19 in March 2020 impacted both the construction and the design of the project. The engineering team worked with the owner to upgrade the on-site mechanical equipment to better prevent the spread of viruses. The filters in each heat pump and the dedicated outdoor air system unit were upgraded to a MERV-13, designed to filter out pathogen carriers such as airborne respiratory droplets in addition to common irritants such as dust and pollen. 

To improve overall air quality, the outdoor air unit — which brings in outside air for ventilation — was designed with an air-to-air energy recovery system. Each zone was provided with increased ventilation to match changing industry standards. 

Fulfilling Environmental Goals

Since the project was completed in 2021, the new infrastructure upgrades have allowed the Stockbridge-Munsee Band of Mohican Indians to save an estimated 63,000 gallons of water annually by removing the need for domestic makeup water used by the evaporative fluid cooler. 

On a broader scale, the geothermal system is designed to provide the health center with 100% of its heating and cooling needs. Switching from using propane boilers to using the geothermal bore field for the building’s heating demand reduced the total annual propane usage by 46,300 gallons — equivalent to $82,140 saved each year. 

Not only does the new system and HVAC retrofit meet Stockbridge-Munsee’s goal of conserving natural resources, but it further lends credence to the tribe’s commitment to be responsible stewards of its land.

The Stewardship Continues

Stockbridge-Munsee Health and Wellness Center’s installation of the new geothermal system is a major accomplishment. It not only empowers the tribe to use renewable energy and achieve a degree of energy sovereignty, but it also sets them up for future steps to decarbonize its community health center further. Future renewable energy generation projects could be coupled with the geothermal heating and cooling system. 

New federal legislation that provides increased tax credits and rebates for energy efficiency and electrification projects via the Inflation Reduction Act (IRA) could be used by the tribe for future improvements. Funding for renewable energy and energy efficiency initiatives is now well within reach, thanks to the IRA. This includes solar electric power generation and battery storage or new high-performance windows and insulation, which can easily be combined with the geothermal system. 

For organizations such as the Stockbridge-Munsee Health and Wellness Center, the will has always been there. Now, the means and the wherewithal are as well.

“Wherever there is opportunity to further our stewardship and lessen the harm we impart on the land, it will be worth the effort,” notes Holsey. 

Andrew DeRocher, PE, is an associate vice president and senior project manager with HGA. He has more than 10 years of experience in MEP systems, energy efficiency and commissioning. His work considers the life cycle of a building and is committed to making systems more reliable, maintenance-friendly and energy-efficient. His expertise includes designing and commissioning data centers, education, health care, lab, office, production and mission-critical facilities.

Marina Hill, PE, is a senior associate and mechanical engineer with HGA. She leads and works on multidisciplinary design teams related to process and HVAC design. Hill’s expertise extends from general building systems to central boiler and chiller plant designs. She is active with ASHRAE and sits on the ASHRAE Milwaukee’s board of directors.