**2.2 Conventional approach**

At this time, the efficient utilization of resources and particularly of energy has become a matter of priority in many aspects of industrial and social planning. The accepted reason is that the rapid increase within the cost of key resources which has made a reappraisal of the many adopted practices necessary. Additionally, there seems to be a case for efficient resource utilization whether it would not be economically justified yet: dwindling raw materials will tend to steer further price increases and scarcities - within the future and conservation in time will help to arrange for such a course of events. Industry was beholding to enhance for energy conservation and to reduce negative environmental impacts but there was no systematic approach to attain it within the past. The improvements were only supported by observations and lessons learned from the previous experiences, sometimes energy optimization problem was very narrowly defined to realize improvements locally which could have adverse effect at a higher level. Accordingly, the facility design approach as shown in **Figure 2**, is improved but only on unpremeditated basis, still no interactions were studied to boost the facility design systematically. The sole system exists was that, usually the starting design of the new facility starts with the best available existing facility design but not always. This can improve the system design for one facility supported on the previous facility design but could not predict the long run design improvements for the same as no mechanism to predict future performance with the needed design modifications.

The conventional approach is predicated on the design of heat recovery system but on impromptu basis, the advantage of it's that some energy efficiency improvements may be subsequently identified. The energy efficiency improvements are supported by experience and without considering the interaction among the systems but supported by design and operation of comparable preceding system. The approach could end in facility with better energy efficiency and straight forward to design due to segregated system but lack benefits of integration. There's no provision within the approach to review interaction among the system to switch the system design. The approach is considered as an unstructured approach to boost energy performance without any feedback mechanism from each system. Moreover, targets supported by trade-off energy values and capital cost do not seem to be generated before the designs as a result future design performance/improvement are very tough to include into design. Consequently, improvised approach to enhance energy efficiency could not lay the inspiration of sustainable energy efficient facility design.

**Figure 2.** *Conventional approach of facility design.*

#### **2.3 Pinch approach**

Energy Integration is that the corner stone of process integration science. While heat recovery was the initial focus of process integration, the scope has been expanded during the late 80's and 90's till the end of the last century to take account of most aspects of process synthesis and design. The single most important concept and therefore the one that gave birth to the sector of process integration is that the heat recovery pinch, discovered independently by Hohmann/Lockhart, Umeda et al. and Linnhoff et al. The Pinch concept is a systematic tool that provides critical information for a complete plant or perhaps site level. The concept is additionally generally applicable in areas aside from waste heat recovery. The main target of this approach is on basic energy recovery and utility targeting, utility selection, integration of heat pumps, heat engines, furnaces, distillation columns, etc., heat exchanger network synthesis and retrofit, combined heat and power integration and process optimization for energy integration [7, 8].

#### *2.3.1 Problem formulation*

Pinch technology is the technique that provides a systematic methodology for energy saving in processes and even total sites. The methodology is predicated upon thermodynamic principles which identify economically feasible energy efficiency improvements. Pinch Analysis was first developed within the late 1970s as a method for optimization of thermal heat recovery, and rapidly gained wide acceptance as a theoretically elegant as based on first and second law of thermodynamics yet practical approach to the design of Heat Exchanger Networks (HENs). Within a short period of time, it's evolved into a general methodology for optimization, based on the principles of process integration.

In Pinch approach, firstly, the core of every process is designed with fixed flow rates and temperatures yielding the heat and mass balance for the process. Then the design of a heat recovery system is completed for every process. Next, the remaining duties are satisfied by the use of the appropriate utilities. Process integration using pinch technology offers a completely unique approach to come up with targets for minimum energy consumption before heat recovery network design. Heat recovery and utility system constraints are then considered within the design of the core process. Interactions between the heat recovery and utility systems are also considered. The pinch design can reveal opportunities to adjust the core process to improve heat integration. The pinch approach is exclusive because it treats each process with multiple streams as a single integrated system. At site level, the waste heat is recovered using utility exchanger network i.e. utility or buffer systems are developed to recover heat from one process and utilize it for other process to attenuate net utility consumption at site level and opportunity to integrate cogeneration. It's been applied successfully not only to energy systems (heat recovery, pressure drop recovery, power generation), but also to fresh water conservation, wastewater minimization, production capacity de-bottlenecking, and management of chemical species in complex processes.

The main advantage of the Pinch approach (shown in **Figure 3**) is that the designed facility is going to be very energy efficient up to the amount that systems are modified for better integration based on the interaction among them. The elements which are missing is the design retrofit-ability (i.e. future design modification as per dynamic energy prices), direct heat integration among the processes, and

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

#### **Figure 3.**

*Pinch approach for facility design.*

waste energy recovery technologies. These elements are going to be incorporated into extensions of pinch approach in future but retrofit-ability can be added to pinch approach in current format or future extensions. It's worthwhile to mention that retrofit-ability is about provision of predicted future modifications into the current design and also the prediction might be better depending upon the approach. The elements direct heat integration and waste energy recovery technologies will affect level of energy efficiency while retrofit-ability is serving to succeed toward the extent whether high or low. Thus, retrofit-ability can be considered as a design criterion for any energy efficiency approach which is capable of predicting future designs from energy efficiency perspective. Pinch approach has all the eminence to qualify the prerequisite of an approach which might be adapted to develop sustainable design. As pinch approach may well be applied to predict the minimum energy consumption of a specified process for a given energy-capital trade-off. Henceforth, the longer-term energy consumption from the process may be predicted, supported by the energycapital trade-off forecast. Therefore, the capital investment requirement to scale back the energy demand may well be extracted from the pinch approach and utilized to make the idea of developing sustainable energy efficient design.
