Meteorological days for HVAC system design in Mediterranean climate

In this paper several real days belonging to a Typical Meteorological Year (TMY) are proposed as design days for HVAC systems in summer conditions. A parameter, the equivalent temperature, that is a different combination of related values of hourly solar radiation, wet and dry bulb temperature, is defined. Real days with maximum values of these parameters are selected as Design Meteorological Days (DMDs) to evaluate summer cooling load. Results are analysed in terms of energetic performances of the system to identify the most suitable DMDs to be used in the design process. The DMD selection is based on the criterion of reducing HVAC part-load working periods and on the risk level to alter indoor design conditions. The approach uses the computer package Integrated ENergy Use Simulation (IENUS), specifically developed for the Mediterranean climate, to characterise both energetic and environmental aspects. Simulations are referred to a non-residential building designed on the base of an energy saving criteria. Typical Meteorological Years are used both as meteorological data inputs as far as data base to select DMDs.