SSM Health St. Mary’s Hospital – Janesville
A retro- and monitoring-based commissioning project uncovered significant savings for this Wisconsin healthcare facility.
The Objective
GBA was retained to implement a retro-commissioning program at this 174,884-square-foot, 50-bed acute care hospital, with the objective of achieving a four- year simple payback and saving 10% of total energy costs compared with the baseline year. The scope included identifying energy savings opportunities, providing scopes of work or necessary design drawings, receiving and reviewing contractor bids, and working with contractors to implement the work. When work was completed, trend data was reviewed and a verification report provided.
Applicable incentives totaling $48,500 were secured through Focus on Energy, which administers incentive programs for several Wisconsin utilities.
The Response
GBA conducted multiple site visits to review operating procedures and equipment operation, review existing drawings and specifications, discuss any known deficiencies, tour the facility and collect nameplate data, perform some preliminary functional testing of major HVAC equipment, and identify energy saving opportunities. GBA used Trend Sumo®, an in-house monitoring-based commissioning (MBCx) software platform, to help identify measures and to confirm persistence of implemented measures. Trend Sumo allowed for repetitive data review and continuous monitoring, quickly pulling data from all AHUs, the chiller and boiler plants, and all terminal units.
Implemented measures with the greatest energy savings impact included condenser water supply temperature reset; discharge air temperature setpoint reset; operating room space setbacks; AHU economizer optimization; and static pressure setpoint reset.
Under normal operating conditions, additional support from the RCx engineer is unnecessary during implementation of measures; however, a complex operating room night setback, including occupancy sensors and manual overrides, was implemented. This work was completed during off hours, but since the hospital is active and OR schedules are full, the surgical team was concerned about cleanliness and resuming normal operations in the morning. GBA, which is not local to the project, held daily construction calls that included facilities and surgical staff and the contractors, reviewing night work and addressing any past or future concerns from the surgical staff. Full coordination was necessary for a successful project completion.
The lobby and kitchen area had a history of poor pressurization since the building opened. GBA used Trend Sumo in addition to up-front functional testing, then had new airflow measuring stations installed and controls sequence programmed to achieve energy savings through night setback—all while addressing the known pressurization issues.
The project exceeded its goal of 10% energy cost reduction, with payback (including incentives) of just 2.09 years. The work also reduced greenhouse gas emissions by 988 equivalent metric tons of CO2. Hospital EUI is expected to decrease from 251 kBtu/ft2 to 222 kBtu/ft2. Results shown below include program costs and incentives.
The work was honored with engineering awards by ASHRAE Illinois and ASHRAE Region VI.
Traditional RCx plus MBCx with Trend Sumo
Eight implemented RCx Measures
New setbacks for ORs and kitchen and lobby areas
Multiple system resets and optimization measures
State and regional ASHRAE awards
The Results
kWh Electricity Savings
Therms Natural Gas Savings
Annual $ Savings
Simple Payback (Yr)
