In the current socio-economic situation, smart products are essential for daily life. Energy is a very much related matter to smart products. To buy a smart product, people mostly care about that smart product’s energy consumption and the price. There is always a tug-of-war between the price of the product and the energy consumption of that product. An energy-efficient smart production system is described in this study where the production is variable, and in the out-of-control state, it produces defective products. For prevention of the out-of-control state, preventive maintenance and restoration are used within the smart production system. The rework policy helps to profit from the defective products, and the warranty policy helps to motivate the users. This model applies an improved strategy to the production process and develops a new product that needs to be marketed. Finally, this model plays a vital role in creating smart products with moderate energy consumption at a minimal cost. The mathematical model is a non-linear profit maximization problem that is solved both analytically and numerically. The classical optimization technique founds optimum solutions. Different numerical examples and sensitivity analysis with graphs are used to validate the mathematical model.

The advertising of any smart product is crucial in generating customer demand, along with reducing sale prices. Naturally, a decrease in price always increases the demand for any smart product. This study introduces a multi-product production process, taking into consideration the advertising- and price-dependent demands of products, where the failure rate of the production system is reduced under the optimum energy consumption. For long-run production systems, unusual energy consumption and machine failures occur frequently, which are reduced in this study. All costs related with the production system are included in the optimum energy costs. The unit production cost is dependent on the production rate of the machine and its failure rate. The aim of this study is to obtain the optimum profit with a reduced failure rate, under the optimum advertising costs and the optimum sale price. The total profit of the model becomes a complex, non-linear function, with respect to the decision variables. For this reason, the model is solved numerically by an iterative method. However, the global optimality is proved numerically, by using the Hessian matrix. The numerical results obtained show that for smart production, the maximum profit always occurs at the optimum values of the decision variables.

The waste of energy in the present era is a dangerous signal for the future. All categories of consumers should come forward to moderate energy use and prevent wastage. This study focuses on a controllable energy consumption-based sustainable inventory model incorporating variable production rates, improved service, partial outsourcing planning, defective production, restoring reworkable items, disposing of non-reworkable items, and energy-saving steps. Reducing unusual energy consumption in production systems reduces carbon emissions and maximizes the system’s profit. An improved service level attracts customers, increases demand, and improves product reputation. Separate holding costs of reworked, defective, and perfect-quality items are considered for every lot delivered and reworked. The demand in the market is related to price and service. A traditional optimization technique examines the global optimization for the profit function and decision variables. Numerical illustrations as well as concave 3D graphs validate the analytical results and provide a sensitivity analysis for different parameters. The model is validated through special cases and comparison graphs.