APPROACH AND METHODOLOGY
A 20 percent energy usage per square foot reduction by 2020 is the major goal of this project, with minor goals of improving operational efficiency and implementing sustainability concepts into the buildings as a means of improving on original design intent. To reach this goal, the Mayo Clinic's approach to retro-commissioning is to analyze their buildings on a five-year cycle by a retro-commissioning team including internal Mayo staff and external parties. External consultants will be evaluated and hired based on experience, cost, and other factors. The consultants will work with an internal Energy Coordinator, Operations staff, and Controls technician to complete the retro-commissioning team.
Roughly six to seven buildings will be investigated and analyzed each year. Original design drawings and intent will be analyzed and compared with current controls sequences and operation. In addition, the building's energy usage history will be evaluated. Major pieces of equipment (examples are lighting systems, heating and cooling systems, and the building envelope) will be tested and their efficiencies will be analyzed. All of the data will be compiled to identify energy conservation measures for each of the building. The measures will be prioritized based on cost and savings before implementation. The Energy Coordinator and funding committees will work together on project selection and implementation.
Due to competing internal interests for projects, a two-year project payback will be used for the first round of retro-commissioning. Mayo Clinic is open to available funding partnerships, incentives, and grants to alleviate internal funding concerns.
IMPLEMENTATION, TIMELINE, AND DELIVERABLES
A five-year timeline for retro-commissioning of the remaining 37 buildings has been identified. The buildings will be broken down into groups based on major pieces of equipment, size, and age. Each year, six to seven buildings will be retro-commissioned. Low cost items (less than $30,000) will be immediately evaluated and implemented. Projects larger than $30,000 with a two-year payback will be brought forward for funding. Additional projects will be prioritized within the traditional capital planning process. The typical retro-commissioning timeline for one building is 90 days, so multiple buildings will be retro-commissioned at any one time. It is also imperative to study the buildings in both the cooling and heating season so buildings may be revisited depending on the schedule.
Major project deliverables will include a retro-commissioning report identifying findings, building history, and energy conservation measures. From the report, measures to implement will be identified. Low cost items can be immediately implemented, higher cost items will be prioritized before completion. After implementation, buildings will continuously be monitored to manage major changes or drifts in utility usage. In addition, the monitoring will allow actual savings to be identified as opposed to estimated savings. Currently all buildings chilled water, steam, and electricity are monitored. Water usage, compressed air, and miscellaneous utilities are monitored in the larger buildings.
Retro-commissioning is utilized to combat rising energy costs, improve operational efficiencies, resolve design misapplication, and ensure buildings are sustainable. Mayo has two major hospitals (3,700,000 square feet) amongst outpatient, education, research, and support facilities (16,925,000 square feet) that range in age from 2-90 years of age. The buildings have changed over the years due to additions and retrofits, so a re-visit of the infrastructure is necessary. The value of energy savings for retro-commissioning is $0.11-$0.72 per square foot and non-energy savings is $0.10-$0.45 per square foot. These savings will allow more dollars to be invested in patient care.
Mayo Clinic's pilot program of two buildings has shown stellar results. The Generose building is a 301,500 square foot building that contains an institutional inpatient facility serving psychiatry and also includes areas of physician offices and a Healthy Living Center for employees. The initial occupancy of the building included inpatient areas with ancillary spaces and shelled areas. It has since experienced significant occupancy changes including laboratory space and the Health Living Center. Conservative estimates show that implementation of low cost retro-commissioning items will conserve 30 percent due a reduction in over-ventilation. The Stabile building is an 185,700 square foot that was originally designed for office occupancy. Since the original construction in 2000, an additional four levels have been added and occupancy has migrated to research functions, including anatomy and autopsy. The major energy conservation items being investigated in Stabile are over-ventilation and heat recovery of major systems.
Financial resources may benefit the project if internal resources are not able to be supplied. Most importantly, best practice information is still greatly needed. Information from how other organizations have contracted retro-commissioning consultants, done retro-commissioning internally, and how the process from start to finish has worked would be very helpful. Mayo Clinic is also interested in hearing about project successes, opportunities, and lessons learned from other organizations, including project recommendations.
