المجلة الدولية للعلوم والتقنية

The main objective of this paper is to design a central air conditioning system for a hospital located at Zuwarah city, Libya. Different types of air conditioning systems were studied and evaluated. Variable air volume system (VAV) had been studied in details and accordingly was selected for the hospital. The outdoor design condition had been determined according to the metrological data for the proposed site using a program called (Autodesk Revit MEP 2015).The nature, the constructions specifications of the site and the building that need to be conditioned were studied. Then; the thermal loads for the building have been calculated. The air volume flow rate was calculated as well and those calculations were essentials in the process of air duct design and duct sizing. The air duct design was obtained using two different methods (Equal Friction Loss Method, and Velocity Reduction Method). The first method was used to calculate the size of the short air ducts, and the second method was used to calculate the size of the long air ducts. Keywords: Heating, Ventilating, and Air conditioning (HVAC) System, variable air volume (VAV), Duct Design, Autodesk Revit MEP 2015.