Gundersen's Green Replacement Hospital Plans

If you’ve been following healthcare sustainability, you’ve likely heard about Gundersen Health System. Gundersen Lutheran facilities had been pieced together over the last century and the physical space no longer met the needs or expectations of patients, families, and staff.   

The organization’s in-house, multidisciplinary team partnered with its design firm, AECOM, and construction management firm Kraus Anderson Construction to add an additional 500,000 square feet to the existing space. 

Gundersen broke ground on the new hospital, which will connect to the existing hospital, in January 2010, and is on track to begin caring for patients in the new space in January 2014.   

The 500,000-square-foot expansion will include a new lobby, emergency services department, imaging, operating rooms, cath labs, pre- and post-surgical settings, a neonatal intensive care unit, private rooms for all patients, and much more.

The Lacrosse, Wisconsin-based health system has embraced practices in LEED-certified construction, solar and wind power, methane recovery, locally sourced foods, mercury-free operations, and recycling—all accomplished with lower operational costs.

Primed for energy savings
One goal for the new construction is to improve energy use to 115 kBTU per square foot, up from the current 240-280 kBTU per square foot. Reaching this goal will put the hospital in the top 1% for energy efficiency of hospitals in the region. At current energy costs, achieving 115 kBTU will save Gundersen Lutheran about $660,000 annually. 

One of the most significant pieces of the energy plan is a geothermal heat pump system, whichtakes advantage of the moderate temperatures underground to greatly improve efficiencies of HVAC equipment. A 300-ton heat pump will be installed along with 156 wells buried about 400 feet underneath a parking lot. At that depth, Gundersen says, the ground is at a relatively constant temperature of roughly 48 degrees Fahrenheit, providing an efficient heating and cooling source year-round. 

It works like this: During the winter months, water from the geothermal wells is sent to the geothermal pump. There, the energy (heat) from that water is used to add heat to the building. The water that had the energy removed is then sent back to the geothermal well to once again have energy transferred to it from the earth.

The opposite happens in the summer months. The cool water from the geothermal wells is sent to the geothermal heat pump, where energy (heat) is transferred from the building to the water. The warmed water is then sent to the geothermal wells to transfer its heat back to the earth. 

In addition, all hospitals have continuous heating and cooling requirements that have nothing to do with outdoor temperatures. For example, heat is always needed for the sterilization of medical instruments, dehumidification, or laundry.

On the other side of the coin, medical equipment, electrical equipment, and computer systems are constantly generating heat.

So the geothermal heat pump system at Gundersen includes an ingenious set-up that will capture this heat and send it to areas where it can be used. By taking advantage of the heat, less energy will be needed from the geothermal wells in the winter, further increasing the efficiency of the system. 

Work on the geothermal system will be completed in Winter 2012 Gundersen anticipates the geothermal heat pump will result in a savings of 70 to 80 kBTU per square foot annually—by far the largest energy-saving component of the new hospital. Gundersen says the system will drastically reduce its dependence on fossil fuels and exposure to fuel price volatility. 

Other elements of the energy plan for the new hospital include: Efficient lighting design with lower wattage lamps and high-efficiency ballasts, occupancy sensors, and fixtures that better disperse light for an anticipated savings of 5 to 7 kBTU per square foot; and a highly insulated building shell (windows, walls, ceilings, etc.), for an expected energy savings of 17 kBTU per square foot.