Building Automation per il raffrescamento naturale negli edifici storico-monumentali. Building Automation for passive cooling in historical buildings.

The management of indoor climate control should aim to keep the comfort conditions constant and uniform in time and space, quickly responding to any changes of the boundary conditions and considering at the same time the long-term hygrothermal behaviour of buildings. In the case of passive cooling, the management has a specific degree of difficulty, do to the fact that there are very few components on which it is possible to act for the control. Inside the reading room of the historical building of the Provincial Library "N. Bernardini" in Leece, a geothermal passive cooling system was installed. It is based on the thermal exchanges air-to-ground and blows air into the room through a displacement system. The unique active elements of the system are the fans, required to compensate for the pressure drops. On the basis of appropriate fields monitoring conducted during the exercise of the system, a strategy of activation of the system itself was result, that takes into account the external climate variations, the microclimate parameters, the indoor thermal loads, but also the large volume involved and the thermal inertia of the structure that dumps the effects of peaks in the variation of boundary conditions. Currently the control on the cooling system is achieved through traditional thermostats and hurnidostats, that detect the climate parameters and manage the activation of the fans and of the actuators for opening windows. However, there are already planned future developments that will replace this kind of control with an other one based on "complex-logics", which involves both thermal and moisture fluxes management. This new control system should work on set-points of comfort that are changeable according with the algorithms of adaptive comfort. Exploiting this new system, there will not be a single check of the benchmarks involved in the control of microclimate, but it will be obtained a management of the plant based on the mutual comparison of these parameters. The purpose is to realize a complete management in which each time there is one decisive parameter, that prevails over the others for the activation of the various plant parts; the decisive parameter will change every time according to the present situation, and will be identified by the system on the basis of proper setting entered in beforehand.