A thermodynamic approach to the microclimate environment of museums

Abstract Historical buildings represent an important part of the cultural heritage and an economic source for Countries. Generally, they are used for public purposes and specifically to host museums and art exhibitions. Even if they are private homes, these buildings must be conserved in their original conditions as possible but have also to guarantee the best preservation conditions for the works of art they contain and a suitable thermal comfort for visitors and people living or working there. Therefore, a technical physical application of thermal comfort control is needed since the human thermal environment is the result of the interaction of air temperature, air velocity and humidity. These parameters are the basis of the designing of comfortable habitat. Thermodynamics plays a key role in the analysis of systems in which energy transfer and energy transformation take place. In this contribution, a second law analysis of the thermal behaviour of the metabolism of a human body under environment changes is performed by means of the extremum entropy generation. The result is that a change in room temperature affects hardly the metabolism. Consequently, thermal and hygrometric control must be developed in historical buildings with particular concern to the stationarity of the heating systems, in order to advantage the visitors. The notions of entropy and its generation are the fundamentals of modern technical and engineering thermodynamics and thermal engineering. Entropy has been proved to be a quantity describing the progress of irreversible processes. Entropy generation allows to describe any irreversible process without mathematical constrains (linear or nonlinear phenomena, open, closed or isolated systems), becoming a very interesting quantity in applications. We prove the usefulness of the entropy generation extremum principle to evaluate the condition of the best comfort in historical buildings.