Fig. 3 shows the monthly consumption of both the NG and electricity in the studied area. Also, Fig. 4 shows their daily use given in millions of British thermal unit (MBTU). Fig. 3. Monthly electricity and NG consumption in MBTU for the area under study Fig. 4. Hourly electricity and NG consumption in MBTU for the area under study
From both figures, it is notable that there is a real chance of using the NGDN as a low-emission fuel source because of the high diversity between the NG and electric power consumption. It should be mentioned that these measurements are performed based on the calorific value (in MBTU) of the NG and the electric power. Besides, from Fig. 2, it is noted that the off-peak periods of the NG loads are almost synchronized …show more content…
5. The system is connected to a utility grid to draw (or deliver) electric power based on the demand conditions. Secondly, an optimal design of the proposed HPGS is presented for minimizing the total annual cost and system emissions using recent meta-heuristic optimization algorithms. Fig. 5. The proposed HPGS
4. PROBLEM FORMULATION
In this section, the optimization problem under study (objectives and constraints) is formulated.
4.1. Design objectives A multi-objective function (OF) is formulated to consider both the total annual cost (TAC) and total annual pollution (TAP), simultaneously, during the design of the HPGS. Mathematically, Eq. (5) presents the primary design goal, which is minimizing the objective functions (f1 and f2) of the proposed HPGS. The well-known weighted sum method is applied to convert the OF to a single function f, where the Pareto optimal solutions of the original multi-objective problem can be defined as follows