Mechanical Drawing Symbols

This mechanical room HVAC plan sample shows the layout of air handler (air handling unit, AHU) equipment: mixing chamber, air filter, fan (blower), heat exchanger coil, diffusers.
"Ventilating (the V in HVAC) is the process of "changing" or replacing air in any space to provide high indoor air quality (i.e. to control temperature, replenish oxygen, or remove moisture, odors, smoke, heat, dust, airborne bacteria, and carbon dioxide). Ventilation is used to remove unpleasant smells and excessive moisture, introduce outside air, to keep interior building air circulating, and to prevent stagnation of the interior air.
Ventilation includes both the exchange of air to the outside as well as circulation of air within the building. It is one of the most important factors for maintaining acceptable indoor air quality in buildings. Methods for ventilating a building may be divided into mechanical/ forced and natural types.
"Mechanical" or "forced" ventilation is used to control indoor air quality. Excess humidity, odors, and contaminants can often be controlled via dilution or replacement with outside air. However, in humid climates much energy is required to remove excess moisture from ventilation air.
Ventilation increases the energy needed for heating or cooling, however heat recovery ventilation can be used to mitigate the energy consumption. This involves heat exchange between incoming and outgoing air. Energy recovery ventilation additionally includes exchange of humidity." [Ventilation (architecture). Wikipedia]
The HVAC floor plan example "Ventilation system layout" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the HVAC Plans solution from the Building Plans area of ConceptDraw Solution Park.