San Bernardino Valley College Retro-Commissioning | P2S
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San Bernardino Valley College
Retro-Commissioning

Project
Background

P2S is working with San Bernardino Valley College's Facilities team on optimizing the chilled water system from the Central Utility Plant. It was determined that the CUP cooling capacity covers the cooling loads of the served building; however, Facilities have been receiving complaints of zones being warm/hot. Concurrently, SBVC is seeking to reduce energy consumption by retro-commissioning existing mechanical equipment at the:

  1. Administration/Student Services Building
  2. Art & Gallery Building
  3. Auditorium
  4. Business Building
  5. Campus Center
  6. Central Plant
  7. Chemistry and Physical Sciences Building
  8. Gymnasium
  9. Health & Life Science Building
  10. Library
  11. Media/Communications Building
  12. North Hall

The intent of this Project is to identify opportunities to optimize equipment operations for improved energy efficiency and occupant thermal comfort for the current use of each building/zone. P2S has performed site visits to assess current equipment operating conditions. The team has also coordinated with the controls contractor to set up trending across the buildings being analyzed. This trend data is being reviewed. All while a master list of findings has been maintained throughout and implementation plans for each building are being developed.

Systems Commissioned

The retro-commissioning scope includes evaluation of the central plant which consists of water-source heat pump chillers, thermal energy storage tanks, cooling towers and pumps. The thermal energy storage tank stores reserve chilled water capacity to help meet the campus demand during peak hours. The central plant serves all HVAC equipment chilled water coils located in the administration student services building, art and gallery building, auditorium, business building, campus center, chemistry & physical sciences building, new gymnasium & field buildings, health & life science building, library, media communication building and north hall building. These buildings contain HVAC equipment such as 4-pipe fan coil units, CAV/VAV systems with 4-pipe air handling units, and 4-pipe rooftop packaged units. 

Challenges

Many existing packaged rooftop units have their own built-in controls, with communication to the DDC system through BACnet. Since the detailed control logic isn’t available at the DDC level, it’s difficult to fully evaluate functional performance in a traditional way.

Instead, we rely on trend analysis to assess system response under different operating conditions. However, verifying performance across different operating modes can still be challenging, especially when space temperatures don’t fluctuate much during the day. We also observed BACnet communication reliability issues, where some units did not consistently respond to DDC commands. On top of that, limited monitoring points further restrict the depth of analysis we can perform. The trend data was also not initially set up correctly at the DDC, which significantly delayed the start of our trend analysis.

In addition, evaluating control logic for the VAV air handling units and central plant was challenging because the as-built sequences shown on drawings often didn’t match the actual programming in the control system. It required engineering judgment to determine whether the existing logic was still appropriate for current building operating conditions and usage.

Solutions &
Lessons Learned

Solutions

Throughout the retro-commissioning process, the P2S Cx team identified many chilled water system optimization and energy efficiency opportunities across the buildings that the facility team can address.

A key focus was a detailed review of the control logic, which allowed us to identify programming mapping errors and setpoint overrides that are relatively simple to correct but have a meaningful energy impact. For example, the chiller on-peak schedule reference point was incorrectly mapped, causing the chillers to operate during off-peak hours. Another example is that the fan coil unit unoccupied override delay setpoints were set to 8 hours, and routine manual overrides by janitorial staff were resulting in unnecessary overnight operation.

Beyond identifying these issues, our team also took the time to troubleshoot and investigate them further to understand the root causes before developing recommendations.

Lessons Learned

One key lesson learned is that accurate trend setup early in the process is critical, especially when monitoring-based commissioning plays a major role in retro-commissioning. Having access to live control logic also greatly improves the ability to properly evaluate system performance.

Another important takeaway is that retro-commissioning cannot rely on as-built documents alone since tenant improvements and system upgrades often shift the original design intent without being fully documented. This is especially true for equipment with packaged controls, where limited monitoring points often require more field investigation to fully understand system operation.

We also learned that even small control issues such as incorrect setpoints or mis-mapped points can have a significant impact on energy performance. Because of this, it’s important to always look at the system holistically and understand how individual issues affect overall building performance.

New Podcast!
Retro-Commissioning in Action at SBVC

Learn more by listening!

In this episode of Focused Solutions, Cx Studio Leader Jake Huang talks about his retro-commissioning efforts at San Bernardino Valley College. P2S Cx helped improve campus comfort and addressed concerns, turning them into an opportunity for smarter performance. Retro-commissioning allowed our team to evaluate the chilled water system served by the Central Utility Plant. We reviewed controls data and identified opportunities to improve energy efficiency, equipment operation, and occupant comfort across multiple buildings.
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