Hygrothermal calculations relating to climatic influences in storage rooms
It is important to give people access to historically valuable collections, but only a tiny proportion of museums’ holdings is actually open to visitors. The lion’s share is kept in permanent storage. Collections are frequently left to municipal archives or to museums; as a result, cultural artifacts that ought to be stored in accordance with conservation requirements frequently end up being kept in poor storage conditions instead.
There is, then, a shortage of storage facilities that satisfy the requirements of sustainability and energy efficiency as well as the demands of conservation. At the same time, there is a lack of financial resources to build expensive storage facilities and install the complex, energy-intensive air-conditioning units needed to satisfy these facilities’ high requirements with respect to indoor climatic conditions. When designing a modular, energy-efficient storage facility for cultural artifacts, the particular demands and constraints that must be taken into account depend on the type of artifact to be stored. An archive storage facility, for example, needs a room temperature of 14-18 °C and room humidity of 35-50 % RH. In a storage facility for paintings, on the other hand, both the temperature and the humidity of the air in the room have to be higher, at 16-22 °C and 40-55 % RH respectively. What’s more, to preserve the archive material, the storage room should minimize short-term fluctuations in relative humidity and room temperature. As a rule, priority must go to improving energy efficiency by way of structural and passive measures, with a view to reducing the amount of systems technology needed within the building.
To this end, we computationally examined various building design alternatives to develop a storage room optimized for energy consumption. Energy requirements can be reduced by almost 30 percent by improving the insulation of the exterior walls, floor and ceiling. Our calculations show that the air infiltration rate in the storage room must be kept to an absolute minimum in order to avoid the kind of large daily variations that are harmful to the artifacts being stored. They also indicate that building moisture can constitute a serious long-term problem, particularly given the room’s low level of air exchange. It is essential to ensure that building moisture cannot escape into the storage room environment. This is particularly true when low thermal mass and moisture-buffering objects are present in the storage facility.