Accordingly, the HVAC control system functions in terms of applying optimal regulation to either the air conditioning and/ or heating system present in a given environment. To be noted is that towards enhancing the basic operation and performance of the HVAC system, there is a need for a ‘sub-system.’ Accordingly, the DDC– Direct Digital Control – system functions as the ‘brain’ behind existing HVAC systems. This is through its functional role-play of dictating the positions of all dampers and valves in a given system. Thus, it is able to aptly determine which of the existing HVAC system chillers, pumps, and fans are effectively running and at what capacity, speed, and/or rate. Ultimately, it is towards more efficient and effective automation that the DDC system is necessary. Existing groups of DDC controllers, whether networked or not, form a complete layer of the system, thereby making it possible to link up various HVAC systems to a central control center (Althouse, Turnquist, and Bracciano 14).

HVAC systems are comprised of various mechanical technologies, hardware, and software components, all of which efficiently work in a systematic ‘pre-programmed’ manner. HVAC in general regards the pertinent technology vital towards both vehicular and indoor environmental comfort. Primarily, its ultimate goal is to provide not only acceptable indoor air quality, but also optimal thermal comfort (Bearg 108). Essentially, a sub-discipline of mechanical engineering, HVAC system design is based upon pertinent principles, i.e. heat transfer, fluid mechanics, and thermo-dynamics amongst others (Bearg 109).

Vital in the design and operational capacity of the various medium to large-scale office buildings and industrial complexes HVAC is also useful in marine environments, i.e. aquariums. It aids in enabling healthy and safe building conditions, through regulation of both humidity and temperature by way of utilizing outdoor fresh air. This entails ventilation of the ‘indoor air’ in any given space, to be replaced by fresh, high-quality air (Bearg 111).