**2.1 Primitive approach**

In primitive facility design approach (**Figure 1**), only core process was designed and utility was provided for all energy consumption i.e. heating, cooling or shaft work with none concept of energy efficiency or perhaps utility targeting. Consequently, the two elements were designed separately with none emphasis on energy efficiency and also the process design is directly dictating the utility system design and there aren't any interactions among systems to boost the facility design. This approach was in practice when the efficient utilization of the resources wasn't priority in any aspect facility design. Nowadays, the approach is sort of extinct for the mass production in process industries, can be found in practice for very small-scale production or for batch processes or processes where the production mechanism is not fully known or could not be controlled with needed accuracy.

The approach is incredibly simple to implement and used generally for complex batch processes, because it is incredibly difficult to integrate them. As process and

**Figure 1.** *Primitive approach of facility design.*

utilities systems are designed separately, only individual systems might be improved and advantages of integration cannot be realized utilizing this approach. The most advantages are simplified design and lower initial investment. There's no element of energy efficiency from demand reduction perspective, hence obtaining a sustainable energy efficient design utilizing the approach is sort of impossible.
