Performance-based maintenance (PBM) is defined as servicing equipment according to operational parameters measured using a comprehensive diagnostic tool with procedures to diagnose suboptimal performance and improve energy efficiency. This pilot is an expeditious demonstration of deploying a new energy-saving technology with installation-level guidance and participation, rather than solely outsourced implementation and monitoring of energy savings and technology effectiveness.

Objectives of this pilot project were to expand the use of proven i-Optimize analyzer technology and demonstrate the benefits and economics of accurate diagnostics and energy efficiency measurement of unitary direct expansion of refrigerant (DX) systems. This offers Department of Defense (DoD) a piloted basis and implementation guidance for including PBM in routine maintenance guidelines for unitary DX equipment and supports DoD’s goals for operation and maintenance (O&M) cost reduction. Successfully piloting this energy saving technology with the installation energy manager and heating ventilation and air conditioning (HVAC) technicians demonstrates to DoD, Energy Service Company, and utilities the value of using PBM for unitary HVAC equipment.

Results show energy efficiency as an energy efficiency ratio and integrated energy efficiency ratio were improved by 30% on average in the group of selected systems that were serviced, compared with a small efficiency decrease in the units that were not serviced. Cost effectiveness of PBM was analyzed in terms of payback period and savings-to-investment ratio (SIR) of implementation cost. Implementation hard costs include technician training on performance-based maintenance, diagnostic analyzer tools, measurement and verification of savings, and servicing labor, parts and materials. Annual savings due to servicing the DX systems selected for the pilot is calculated to be 21%.

Modeling suggests a PBM program at various DoD locations would produce energy savings of $81,000 to $116,000 per year on an estimated hard implementation cost of $114,000 per service cycle of two-years for 60 DX systems of average size 12-tons at $0.10/kWh electric rate. For this example, implementation cost is $1900 per DX unit. Projected simple payback period is 6 to 8 months with an SIR of 1.5 to 2.3 across a range of climates and electric rates, meeting suitability criteria as an energy conservation measure under most Utility Energy Service Contracts and Energy Saving Performance Contracts.

Overall qualitative assessment indicates positive acceptance of PBM by the DoD personnel who participated in the pilot, shaded by concerns about adequate resources to support proper unitary DX maintenance. Representative Naval Air Station Key West energy manager, HVAC technician and public works director comments are shared in this final project report. Implementation issues at the host installations center around insufficient resources. Severely understaffed and lacking adequate tools, parts and materials, HVAC technicians are scarcely able to keep up with basic maintenance tasks. Furthermore, about half of the DX systems they are responsible for are well past their lifespan and in poor condition due to years of deferred maintenance, resulting in a pervasive need for unbudgeted emergency repairs and hurried replacements, which perpetuates the cycle. As such, the project team found it challenging to implement an advanced, forward-thinking O&M protocol in a setting that has difficulty meeting even the most basic O&M principles and operates day-to-day with uncertainty.