Modeling of Production Plan and Scheduling of Manufacturing Process for a Plastic Industry in Nigeria

In this work, production plan was developed for a plastic company with two products that are made up of five parts.  The production inputs for each part were analyzed and established. The production constraints in terms of materials available, machine capacities, time and labour were used to develop an integer linear programming model to achieve the objective function. The integer linear program was then used to find the optimum quantities of each part that will yield maximum profit. The developed model was analyzed with TORA optimization solver to obtain results for different constraints. The optimum solution for the LP model gave a monthly production profit of N3,751,922. Further sensitivity analyses performed for different production conditions gave results that are not feasible and the ones that were feasible were not optimal. A decision support system was developed for production planning to help the manager in scheduling decision process. The model is now been used at EagleHeights Plastic Industries Limited for their production planning. Keywords: Production Plan, Optimum, Linear Program, Constraints, Sensitivity Analysis, TOR

Life Cycle Cost Analysis of a Diesel/Photovoltaic Hybrid Power Generating System

This work is a Life Cycle Cost (LCC) analysis of a diesel/photovoltaic hybrid power generating system for an off-grid residential building in Enugu, Nigeria. It aims at optimizing different hybrid system configurations, and comparing the result obtained with the photovoltaic standalone (PVSA) system and conventional diesel standalone (DSA) system. The lifetime of the project is 25 years and a real interest rate of 9% per annum is assumed for the system analysis. The average hourly electrical load demand data for residential sector in Enugu were obtained from the power holding company of Nigeria (PHCN). The solar resource data for the location for the year 2010 were gotten from the NASA Langley Research Centre. The sizes of different components were determined to make sure their sizes suit the load demand. A PV standalone system is firstly sized, after which modules of the PV array are removed in sequence to get six different sizes, at the same time, introducing the diesel generator to make a hybrid system. The hours of operation of the diesel generator increases as modules are removed from the PV array. Optimization of the hybrid system is done to determine the system configuration that would satisfy the load demand at minimum cost. The result shows that the hybrid system with 20 modules and a 2.5 kVA diesel generator will serve the load at minimum cost. A life cycle cost analysis of the systems is done using the Net Present Value (NPV) and Internal Rate of Return (IRR). The result shows that the LCC of the hybrid system is N3,459,274.00 that of DSA system is N7,098,192.00 and N3,594,881.00 for the PV standalone system. The NPV of the hybrid system is N3,638,918.00 when compared with the DSA system and the internal rate of return is at 26.3%. The NPV of the PV standalone system when compared with the DSA system is N3,428,747.00 with its internal rate of return at 24.6%. The results obtained show that the diesel/photovoltaic hybrid system is economically the best option for power generatio