Natural versus Mechanical Ventilation: A Case Study of two Hospital Wards

Abstract

The present paper describes a recent study of the indoor environmental quality in patient wards in two hospitals in Vienna, Austria. One of these hospitals relies exclusively on natural ventilation for patient rooms, the other depends solely on mechanical ventilation. The main objective was a comparative assessment of both natural and mechanical ventilation in view of their objective and subjective implications on indoor environmental quality (IEQ) in the summer season. Measurements of IEQ indicators as well as survey-based assessment of hospital staff were conducted. Furthermore, the feasibility of natural ventilation with regard to energy performance was explored via calculations. The results point to relatively favorable IEQ conditions in both hospital wards. The study also highlights the very different thermal comfort requirements of patients and staff. Finally, calculations reveal the energy efficiency advantages of mixed ventilation systems, but point also to their higher installation and maintenances costs.