HVAC Commissioning: Rockford Riverfront Museum
Project Location: Rockford, IL
Facility Type: Museum Complex (Discovery Center, Art Museum, Dance Company)
Project Focus: HVAC Renovation & Control Optimization
Services Provided: Construction Phase Commissioning (Cx), Functional Performance Testing (FPT), Deficiency Tracking & Resolution
Systems Commissioned: (8) Single-Zone VAV Rooftop Units (Aaon RN/RQ Series), (1) Multi-Zone VAV Rooftop Unit (Aaon RZ Series), (26) VAV Terminal Units (Electric & Hot Water Reheat), Critical Room Cooling Unit (Liebert CRCU), Building Automation System (BAS)
Precision Climate Control for Cultural Heritage
The Challenge: Modernizing Museum Infrastructure
The Riverfront Museum Park houses multiple distinct tenants, including the Rockford Art Museum and the Discovery Center, each with unique environmental needs. The facility undertook a major renovation to replace an aging, centralized built-up air handling unit with a decentralized system of modern Packaged Rooftop Units (RTUs).
The primary challenge was ensuring these new systems could maintain strict "Class A" temperature and humidity setpoints required for artifact preservation. In particular, the art gallery spaces required precise humidity control to prevent deterioration of sensitive collections, while the Dance Company studios needed flexible comfort cooling for high-occupancy loads.
The Solution: Construction-Phase Commissioning
Sheehan Engineering was engaged to verify that the new mechanical design—featuring sophisticated Aaon rooftop units with active dehumidification and energy recovery wheels—performed to the Owner’s Project Requirements.
Our scope included rigorous Functional Performance Testing (FPT) of over 35 unique system sequences. We focused heavily on the "handshake" between the new Building Automation System (BAS) and the onboard unit controls, ensuring that complex modes like dehumidification and economizer cycles operated without conflict.
Key Deficiencies Identified & Resolved
Over the course of the project, we identified and helped resolve 118 specific issues. Key findings included:
Erratic Humidity Control Logic: We identified that the single-zone VAV units serving the galleries were rapidly switching between heating and cooling modes due to aggressive PID loop tuning. This instability threatened energy efficiency and equipment longevity. We worked with the controls contractor to stabilize the loop responses.
Unoccupied Humidity Cycling: The original control sequence allowed units to run continuously overnight if humidity limits were exceeded, leading to excessive energy use. We recommended implementing an "Unoccupied High Humidity" setpoint with a specific offset, reducing after-hours runtime while maintaining safe preservation limits.
Acoustic Issues in Critical Zones: During testing of the VAV terminal units, we flagged excessive noise levels in meeting spaces. By adjusting the maximum airflow setpoints and verifying downstream diffuser performance, we mitigated the noise to acceptable levels for meetings.
Economizer & Damper Failures: On a large critical multi-zone unit (RTU-9), we detected a recurring "Economizer Failure" alarm and a mismatch between the commanded vs. actual damper positions. Identifying this early prevented potential fresh air starvation and pressurization issues.
The Results
The commissioning process bridged the gap between installation and operation, delivering a system that the facilities team could trust.
Validated Preservation Environment: Verified the Critical Room Cooling Unit (CRCU) in the archives could maintain precise temperature and humidity stability with minimal drift.
Operational Confidence: The facility staff received a verified system with a clear "deficiency log" of resolved items, ensuring no lingering construction issues were inherited by the maintenance team.
Energy Intelligence: Through trend analysis, we optimized start/stop schedules and verified that energy recovery wheels were engaging correctly to reduce utility costs.
“Construction phase commissioning minimizes issues at occupancy. For a museum, it provides the peace of mind that the climate control systems are actively protecting the collection from Day 1.”
