University Hospital is one of the largest facilities in UW Health’s portfolio. The facility consists of a hospital with 505 inpatient beds and 117 medical clinics, UW Medical School offices, and research labs.
UW Health saw an opportunity to curb University Hospital’s energy intensity through retro-commissioning after a successful 2012 project on their largest outpatient clinic yielded a 1-year payback. In partnership with Sustainable Engineering Group (SEG), the third-party engineering firm used for the pilot project, UW Health is retro-commissioning several buildings in addition to University Hospital.More
UW Health’s sustainability director believes retro-commissioning is one key component in guiding the integrated health system towards its Better Buildings Challenge goal to reduce energy use intensity 20 percent by 2023. The organization’s sustainability strategy is centered on a commitment to energy improvements that enhance both patient and staff comfort.Less
In 2013, SEG conducted a retro-commissioning study of both the University Hospital and American Family Children’s Hospital in which they identified $1.8 million of potential annual savings ranging from easy, short-payback measures to building renovations. UW Health instructed SEG to focus on no- and low-cost measures with a 2-year payback or less. Once the list of improvement measures was established, UW Health applied to Wisconsin’s Focus on Energy Retro-commissioning Program, which offers financial incentives for customers implementing energy-saving projects. UW Health was accepted into the retro-commissioning program and an incentive agreement was established based on estimated savings that would result from the project. Phase I of the project began in 2014, focusing on three primary measures:More
- Equipment scheduling and optimization;
- Daylighting and lighting controls; and
- Fume hood and lab rebalancing.
SEG identified numerous opportunities to save energy by optimizing HVAC equipment to coincide with occupancy. For instance, spaces not in constant use, such as clinics and offices, were programmed so humidifiers were disabled in unoccupied mode. When occupied, SEG observed that non-critical spaces such as clinics, offices, and UW School of Medicine laboratory spaces were operating with more humidity than necessary. According to ASHRAE Standard 170-Ventilation of Healthcare Facilities, many of these space types do not have a minimum humidity requirement; however, to maintain occupant comfort, set points were reduced to 20 percent relative humidity.
Additional measures included increasing the time the building can cool with outside air, identifying HVAC equipment utilizing excessive energy to condition the building, and ensuring ventilation and exhaust rates in the buildings were correct for the space usage.
SEG also developed a daylighting strategy for the atrium. Controls were programmed to either dim or turn off overhead lights when natural light was abundant.
Lastly, SEG reduced exhaust fume hood flow and rebalanced the exhaust system, which resulted in significant laboratory energy savings. Airflow scheduling was redesigned and SEG worked in conjunction with the company Professional Systems Analysis to rebalance the supply, exhaust, and air handler flows. A variable frequency drive was installed on the exhaust fan serving the system and the duct static pressure was reduced. The combination of the reductions in exhaust flow and duct static pressure lead to a 50 percent drop in supply and exhaust fan energy use.
A summary of total cost savings achieved by the three primary measures implemented at University Hospital is included below:
|Measures Implemented||Total Cost Savings ($/year)|
|Equipment scheduling and optimization||$342,186|
|Daylighting and lighting controls||$6,257|
|Fume hood and lab rebalancing||$77,184|
The total cost of the project, including audits and Phase I implementation for both facilities, was $488,075. Focus on Energy provided $335,641 of approved financial incentives. With an annual energy cost savings from all implemented measures for both facilities totaling $486,124, the resulting payback period was less than four months.
UW Health has retained SEG to continuously audit, maintain, and improve the performance of the buildings that were retro-commissioned as well as assist in the evaluation of new buildings. With ongoing commissioning and a second phase of retro-commissioning, both facilities are expected to continue achieving year-over-year energy reductions.Less
The internal energy and water team – which includes the UW Health Sustainability Director, SEG, utility companies, facility and engineering services, planning design, and construction – view the progress of these improvements by sharing facility data through ENERGY STAR Portfolio Manager. By seeing the success of these improvements, the UW Health staff gain awareness of the benefits of building in energy efficiency to daily operations. Since the project’s baseline, University Hospital’s ENERGY STAR score has improved 16 points.More
Additionally, marking continuous progress through weekly checks-ins on the various improvement measures has encouraged a dedicated team effort among the building owners, staff, contractors, and maintenance team.Less