*2.3.3 Outcomes and limitations*

The outcome from pinch approach may be a system that has benefits of energy recovery and in-process modifications for all processes and supplementing with energy utility system as shown in **Figure 5**. This approach is predicated on the economic trade-off between energy cost and equipment cost but only for a given set of values at some extent of time. The draw-back or limitation of such design is that, it does not consider the long run energy values escalation as compared to equipment cost and also future environmental regulations. These constraints are a hindrance to create the facility competitive from energy efficiency, environment or margins perspective throughout its life-cycle. All future retrofits will either require higher Capex for execution or infeasible as no provision were made within the original design for the mandatory alteration. Although, pinch design is predicated on energy values and equipment cost trade-off for the beginning of facility life-cycle but never considers the long run trade-off within the design.

One way to urge "Sustainable Energy Efficient Facility Design" is to urge sustainable design for every process within the facility which shall be modified for energy efficiency at any point in its life-time with none restraint due to its current design. A crucial feature of Pinch approach is that the ability to spot Performance Targets before the design planning is started. The ability to spot the target is the minimum requirement to appreciate sustainable design because it sets the footing of future designs and also the modifications required to attain it. The element of retrofit-ability is missing in Pinch approach but the developed design has enough flexibility (degree of freedom) to embrace this extra constraint. The approach must be extended beyond present Pinch Methodology to develop designs for all predicted trade-off values

*Sustainable Energy Efficient Industrial Facility Design DOI: http://dx.doi.org/10.5772/intechopen.108829*

**Figure 5.** *Facility design based on pinch approach.*

for the upcoming facility lifecycle. All the developed solutions for ever-increasing energy-capital trade-offs shall be compiled together to merge into one design which shall be modified within the future to urge subsequent designs. Finally, the availability of all identified future modifications shall be incorporated in the specified design and provisions are made for the subsequent modifications. The design developed might be modified with none hindrance at any point supported by the trade-off and could be considered as sustainable energy efficient process design. The sustainable process design approach may well be applied for each process of the facility to urge a "Sustainable Energy Efficient Facility Design". The facility design developed with these principles has all the elements of sustainability but lacks elements which are highlighted earlier as pinch approach limitations.

Although, Pinch Methodology is incapable of developing sustainable energy efficient design but the pinch framework may be utilized to develop it. Elements which are vague in Pinch approach is retrofit-ability, process to process direct unification, and waste energy utilization technologies needs scientific community attention. In future, a framework has to be developed to handle of these limitations and take away deficiencies to develop a well-integrated energy efficient retrofit-able design which may be "Sustainable Energy Efficient Facility Design".
