Library uses new dehumidifying technology to fight mold

Publication Date

Aspergillus. Cladosporium. Exotic sounding but most of the time, pretty harmless. But giving just the right temperature, these white powdery molds can be devastating to the bindings on certain types of books, as the Schaffer Library found out about two summers ago. Over 12,000 books had to be removed from the shelves, cleaned and quarantined at an off-site facility. But this spring, thanks to a retrofit of the heating and cooling system that adds new dehumidification capabilities, the books are back on Schaffer shelves. And in an added bonus, excess heat generated from the new equipment will be redirected next door to the geothermal wells in the Wold Center, boosting energy efficiency in that building by 10 percent.

Back in 1998 when the Schaffer Library was renovated, libraries across the northeast weren’t built to include humidity control, most figuring the climate didn’t warrant it. For the most part, the only sections to feature additional temperature control systems were special collections, as was done in Schaffer. But the exceptionally heavy humidity over the last few summers changed all that.

“These molds can be found on just about any book and for the most part, are pretty dormant,” said Loren Rucinski, director of facilities. “But all it takes is a slight elevation in temperature to make it turn really destructive and that’s what we faced. Although harmless to humans, it began to attack books in our collection that had a specific type of binding and was beginning to contaminate other books. Something had to be done.”

The mold growth presented a particular challenge during the ‘shoulder’ months – April through June and August through November - when Union switches between heating facilities and cooling units and when temperatures can be at their most erratic. Library personnel and Physical Facilities staff joined forces to explore a broad range of solutions. First off, the books were quickly removed from the stacks to prevent further spread of the mold and stored. The next step was to bring in heating and cooling consultants, the Polygon Group. Widely known for their work in specialized temperature control, Polygon worked with Union staff to determine the exact level of humidity needed – below 50 percent – and the most cost-effective way to provide a permanent fix. Polygon also cleaned and stored the books in their facility in Massachusetts while Schaffer’s temperature and humidity were stabilized.

Initially, rented descant units from Polygon, which absorbed the moisture in the air and lowered the humidity without adding heat, seemed to be a step in the right direction. But these units were expensive and used up a lot of electricity. Last summer, when the humidity was at its highest, the rented units drew 17 percent of all the electricity used on campus.

An alternative solution had to be found – and Facilities found one: a complete retrofit of the existing heating, ventilation and air conditioning (HVAC) system to include new dehumidification equipment. Designed, manufactured and installed by leading HVAC system provider, Daikin McQuay, the new equipment also features a web-based monitoring system – the Johnson Controls Metasys Automation system - that allows the Facilities staff to monitor and/or control the Schaffer Library from any web browser on campus.

This is how it works: For most of the year, outdoor air coming into Schaffer is chilled, causing moisture in the air to condense and drop out. But this lack of moisture also makes the air feel much colder than it is, so to make it comfortable to work in, the air is reheated to between 68 - 70° and in doing so, the humidity drops like a stone. During the shoulder months, when neither the main campus chiller nor the steam boiler plant are running, the new Daikin-McQuay equipment will ‘kick-in’ to ensure that temperatures and humidity remain stable in Schaffer. In keeping with Union’s commitment to sustainability, the waste heat generated from chilling the air will then be reused to reheat it. An added bonus is that more heat is generated than is needed in Schaffer so the excess will be redirected to the geothermal wells in the Wold Center, where it will be used to serve that facility’s temperature needs.

“Using the newly designed system over the rented dehumidifiers represents a cost avoidance for us,” said Steve Hassett, supervisor of technical controls. “In order to preserve the holdings in the library for future generations, we had to solve the humidity problem in Schaffer no matter what. A more traditional system would have meant significantly higher operating costs for us. But with the upgraded HVAC system, we were able to find a permanent and sustainable solution.”

Frances Maloy, College librarian, couldn’t be happier. “This has been a truly collaborative project,” said Maloy. “Everyone immediately understood what this situation could mean to our library and everyone involved in finding a solution took ownership of the problem. Even the students were good sports about it, helping to clean books and putting up with temperature swings as we tested out various solutions. I am also very grateful to Therese McCarty, vice president for academic affairs, and President Ainlay for their support – we couldn’t have done it without them.”

The retrofitted HVAC system, which cost around $800,000, was funded by President Ainlay through support set aside by Union’s Board of Trustees for projects that are considered to be of importance to the College’s well-being.