Design the retrofit through different thermal comfort indexes: numerical and experimental study in a surgery block of Italian hospital

Various approaches are employed for refurbishing healthcare facilities, yet indoor comfort is often overlooked. Furthermore, there is no consensus on the most appropriate indicator to assess comfort in such buildings. This paper presents a combined experimental and numerical study to evaluate the effectiveness of efficiency measures applied to the building envelope, based on the minimization or maximization of an optimal index describing indoor conditions. Occupant feedback was used to identify the most suitable index for a surgery department located in a Mediterranean climate during the summer season. The results indicate that the most reliable indices are Discomfort Volume or Degree-Hour of operative temperature. Minimizing this index requires interventions targeting the glazed components of rooms. In particular, the use of external shading devices or selective glazing can reduce the optimal index by up to 30%, resulting in a decrease of the mean indoor operative temperature by up to 1.3°C.