e-Climate Notebook assesses the risk of natural aging (oxidation), corrosion, mold and mechanical damage caused by large fluctuations in relative humidity. Data has traditionally been entered into e-Climate from data-loggers downloaded at regular intervals, but an interface would allow collection managers to see real-time conditions in collection areas and immediately assess risks and benefits from changes in control settings.
Thus began several months of intensive preparation to apply for a grant from the Washington, D.C.-based National Endowment for the Humanities (NEH) program for Sustaining Cultural Heritage Collections.
The grant would fund a significant part of the control upgrades and the ongoing monitoring and system refinement. Ultimately, Winterthur’s experiences would develop protocols and procedures useful for other cultural institutions. In September 2012, Winterthur received a $350,000 grant from NEH. The success of the grant application was the result of open and intensive collaboration between Winterthur’s facilities and conservation departments and Limbach Engineering & Design Services, coupled with input from credible and respected consultants.
The Outcome
Under Castle and Price’s leadership and working with Limbach Engineering & Design Services’ talented and innovative staff, Winterthur has implemented 33 facilities improvement measures (FIMs) during the last two years. The FIMs have helped Winterthur reduce energy consumption by 20 percent while stabilizing and often improving the environment in collection spaces.
With volatile weather and energy costs, a payback period is difficult to predict, but the project has exceeded initial estimates. These FIMs changed the environment, upgraded infrastructure, reduced energy consumption, instituted effective real-time system monitoring, and gave facilities staff and conservators the tools to track and understand what is happening in their unique museum.
In addition to the web-based control system, the most significant FIMs include:
- Mapping the entire mechanical system to identify problem areas and anomalies.
- Increasing the number of sensors in 175 Museum rooms from 29 to 78.
- Repairing return dampers on two major air handlers to reduce outside air and restore balance.
- Replacing boiler-burner controls to allow a 1:10 turndown ratio, replacing the 1:3 controls and installing a VFD.
- Installing VFDs on all air handlers and soft starts to accommodate energy cycling.
Although these upgrades were critical, the most significant change has been in the assumptions that govern control of the HVAC system. For many decades, cultural institutions demanded flat-line energy control at 70 F and 50 percent relative humidity with very tight tolerances. Winterthur’s system was designed and run to meet those standards, meaning that all components—chillers, air handlers and boilers—functioned at near 100 percent capacity much of the time and controls were set to the worst-case scenario. For example, reheats were set at 82 F winter and summer, requiring induction units that adjust the air temperature in each room to overcome a large temperature differential to cool the spaces in the summer. Reheats are now programmed to coordinate with the supply air and outside temperature, providing more nuanced control and significant energy savings.
The proof of the conservation program’s results can be found in the numbers. From 2012-14, the number of degree days (temperatures above and below 60 F that call for heating and cooling) rose from about 5,050 to about 5,750. However, Winterthur’s average gas consumption fell from 750,000 to 600,000 cubic feet, and its average monthly electrical usage fell from about 750,000 kilowatt-hours to about 600,000 kWh. Ultimately, the average monthly utility bill dropped from $105,000 to under $80,000.
Next Steps
With mechanical upgrades nearly complete and a vastly improved monitoring and control system, Winterthur is now positioned to continue lowering its energy consumption. Energy cycling began in January 2014 to test the buffering capacity (ability to maintain adequate temperature and relative humidity) of the Museum if the chiller and air handlers are turned off at night. The team discovered that during winter months, buffering for this building was adequate to 25 F and during summer months up to 80 F. Similar testing continues for all seasons and buildings, taking outside temperature, relative humidity and dewpoint into consideration. More nuanced control will further enhance savings; on cool, dry summer mornings the system may come on later and the chilled water temperature may be allowed to rise 1 degree (10 percent energy savings) if the forecast is moderate.
Limbach Engineering & Design Services continues to work closely with Winterthur under a continuous commissioning agreement to ensure mechanical systems function at maximum efficiency, address the shrinking list of anomalies and problem areas, and tune the control system to maximize energy savings. This program promises to keep the facilities and conservation teams in front of operational and control strategies while maintaining a preservation environment for the collections, making Winterthur a leader in the museum energy-conservation arena.
Learn more
Visit the Wilmington, Del.-based Winterthur Museum, Garden & Library website and the Image Permanence Institute, Rochester, N.Y., website for more information.