HVAC mechanical design is the process of designing a heating, ventilation, and air conditioning (HVAC) system to meet the needs of a particular space. This includes selecting the right components, such as air handlers, chillers, boilers, and pumps, and designing the ductwork and piping to ensure efficient and effective operation. The design must also consider factors such as energy efficiency, noise levels, and air quality. The goal of HVAC mechanical design is to create a system that meets the needs of the space while also being cost-effective and energy-efficient.