There are many options for museums to tackle climate action and become more sustainable, but recent work at two institutions has highlighted the value of one particular method: creating “microclimates” that confine environmental conditions directly. in the windows. These solutions, combined with creative programming and exhibit design, ensured museum-appropriate humidity control for the exhibits while improving visitor comfort and well-being and dramatically reducing associated costs. and energy consumption. Such methods will become increasingly essential and relevant to meet today’s demands of limited budgets, visitor engagement and carbon reduction targets.
Why is this important
A museum energy data set compiled in 2017 shows that many museums have much higher energy consumption intensity (a measure of efficiency measured in kBtu / square foot) than many other types of buildings. Some are more energy intensive than large downtown skyscrapers or 24/7 hospitals per square foot. One of the main reasons for this intensity, besides public uses like after-hours entertainment and on-site dining establishments, is the tightly controlled temperature and humidity standards for collection spaces. To meet these standards, it takes a lot of heating and cooling, humidification and dehumidification to condition the air.
In other words, while some museums have made strides over the past decade, incorporating renewable energies on-site and drastically reducing energy consumption, there is still a long way to go in many institutions, and monitoring climate is a key area to focus on.
A look at the care of the collection
The detrimental effects of uncontrolled relative humidity on museum collections are well known, including mold outbreaks, pest activity, corrosion of metals, peeling paint, and cracks in wood, among the most common signs. more visible. In storage spaces, museums can sustainably manage environmental conditions in several ways, from specially constructed passive house buildings to low-energy mechanical system operation. In traveling exhibitions, however, current loan requirements generally allow very little flexibility in relative humidity, and the tighter the control, the greater the energy expenditure required.
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This is where microclimates can be of great help. A microclimate is a space within a larger one where conditions differ. In this case, it is a question of creating a space around the exhibited objects with the relative humidity parameters required for a safe display of the objects, allowing better conservation conditions at a lower energy cost. When properly sealed, display cases act as a buffer against fluctuations in relative humidity in the largest display area. The museum can then relax the ambient conditions in the exhibition area itself to achieve the threshold of low visitor energy consumption and human comfort.
Two recent examples, at the National Nordic Museum and the USS Constitution Museum, demonstrate how microclimates can be an effective solution for institutions of all sizes.
The National Nordic Museum: Use of desiccants in exhibition cases
By building a new facility opened in 2018, the National Nordic Museum achieved the Low Energy Intensity (UIE) of 62.3 kBtu / sqft based on real world utility bills, 48 percent lower as the benchmark of 120 kBtu / sqft at design time, for which it won a 2020 AAM Sustainability Excellence Award (SEA).
As a museum located in Seattle, an area of the country known for its high seasonal humidity, a major obstacle to this achievement was devising how to maintain appropriate humidity levels for objects without consuming much energy. The solution identified by the museum, in collaboration with Ralph Appelbaum Associates, is to use microclimate control in some cases containing objects requiring specific climatic conditions. To do this, it uses ArtSorb, a preconditioned silica gel that can maintain relative humidity at 40, 50 or 60%. The amount of gel needed depends on the size of the space to be packaged, and it comes in different forms for use in a range of applications, including sheets within framed works on paper and in frames. “Bricks” that can be integrated into the housing itself. Several times a year, staff inspect the crates using the gel to ensure that they are functioning properly.
An unexpected bonus of this solution was the ability to create a better experience for visitors, as by meeting the needs of the artwork locally, the gallery design could be more flexible without the need for doors to contain the environmental conditions. . It also saves considerable energy and financial resources, as the main galleries can have much larger humidity ranges.
The USS Constitution Museum: Mechanical systems dedicated to exhibition cases
Another institution, the USS Constitution Museum (part of Boston National Historic Park), worked with Innovative Construction & Design Solutions, LLC, to explore options for controlling relative humidity. Between the options to control the entire gallery at 70 ° F and 55% relative humidity or to maintain it in conditions of human comfort and to use four individual mechanical systems to condition the display cases to the control of relative humidity, the museum chose the latter option. It uses Keepsafe systems, a microclimate device placed near the display module. Even rough estimates indicate that the savings are significant (see tables).
By separating the conditions of the gallery and the exhibition case, the museum focuses on the localized control of special artifacts. The museum reports that the Keepsafe system has been consistent, reliable, and primarily requires only water level monitoring. The solution respects the fabric of the historic building, which faces humidification in winter, and allows the museum to display objects that would otherwise be too sensitive to display.
Both of these examples, using desiccators or a dedicated mechanical system to control relative humidity, focused on creating microclimates in display cases to provide appropriate conditions for the items on display, rather than controlling large volumes. of space. Decoupling the display of objects or collections with the larger gallery space can lead to significant energy savings. A quality building envelope could promote these objectives. Whether through the housings themselves, the use of desiccants or small dedicated active units, microclimates have proven to be a more cost effective and environmentally friendly way to provide safe environmental conditions for museum exhibits.
This approach, along with others (such as re-examining environmental requirements for loans, re-examining easing setpoints, and installing building system controls) may be essential in developing a plan for a museum in order to reduce its energy consumption and carbon footprint while remaining a guardian of its collections and of the planet. “Museums and cultural institutions are spaces that inspire creativity, ingenuity, passion and expression. I can’t think of a more important time for our museum sector to come together while harnessing these traits to do its part for our climate, ”said Julie K. Stein, AAM Board Member and Executive Director of the Burke Museum in Seattle, which constructed a new building with sustainability, energy use and carbon reduction at the forefront. “As the United Nations Climate Change Conference approaches this year, there is an incredible opportunity for our museum community to rise to the challenge together. “
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