HVAC systems to control microclimate in the museums

The growing interest in Italy for the tutelage, the restoration and the valorisation of the historical-cultural resources and the necessity of a better conservation of the artworks of great value require that the museums be provided with appropriate HVAC systems for the control of the ambient conditions. The suitable microclimate for the conservation of the works inside a
museum can be identified by means of a multisubject investigation.
In order to preserve the artworks, the museum requires a flat line for temperature and humidity around the clock, a far more stringent requirement with respect to average commercial buildings.
The temperature and in particular the relative humidity considerably affect the behaviour of the materials in general and of the hygroscopic ones in particular, because they tend to establish a thermal-hygrometric balance with the surrounding environment. So, the ambient thermalhygrometric conditions have to be stable. The control of the indoor relative humidity must assure that in the materials there is no absorption or condensation such to develop chemical and
bacteriologic reactions and induce mechanical solicitations.
Therefore, it is necessary to maintain the ambient conditions by handling especially the indoor thermal loads, which considerably affect the microclimatic values for the conservation. In particular, the load due to the presence of people in the expository rooms is really important, because it is generally impulsive and directly proportional to the over-crowding degree.
On the basis of these considerations, a case-study concerning a simulated museum, built according to a modern conception, is presented in this paper. The indoor spaces of the museum are destined to exhibition room, stock space, conference room, laboratory, restoration and study center, communication.
Using the dynamic simulation code DOE 2.1 E and hourly typical climatic data (TRY), opportunely elaborated, the operating costs of suitable HVAC systems have been evaluated, as well as the requested capacity of control of the thermal-hygrometric ambient parameters.
Our department (DETEC), involved in a competence centre (Regional Competence Centre for the development and transfer of the applied innovation to the cultural heritage and landscapes), is specialized in the theoretical and experimental study of the HVAC systems applied to cultural resources.