This study is the second part of the theoretical study of “Modeling and Simulation of a Two-Stage Air-Cooled Adsorption Chiller with Heat Recovery”, which is based on developing a theoretical model for a two-stage adsorption chiller with an activated carbon/methanol pair. The following models were conducted numerically using MATLAB. The model was based on 10th order differential equations; six of them were used to predict bed, evaporator and condenser temperatures, while the other four equations were used to calculate adsorption isotherm and adsorption kinetics. In this second part, bed heat exchangers and evaporator and condenser heat exchangers are studied by varying the parametric design of a chiller. This includes but is not limited to activated carbon mass inside a single bed, overall heat transfer coefficient for the bed and evaporator and the mass flow rates of all components comprising the chiller. The optimum values increased the COP from 0.35 to 0.4, while the cooling capacity was slightly changed. The COP is 95% of a Carnot cycle working at hot water temperatures as low as 60 °C, and 90% at hot water temperatures as high as 90 °C. It was found that the simulation model results for the two-stage air-cooled chiller agreed well with the experimental data in terms of cooling capacity (6.7 kW for the model against 6.14 kW for the experimental result at 30 °C cooling water temperature). The model optimized the adsorption/desorption time, switching time and heat recovery time to maximize both cooling capacity and COP. Moreover, the model is used to study the effect of activated carbon mass, size of beds and mass flow rates of cooling, heating, chiller and condenser on both cooling capacity and COP.

In the proposed work, the MATLAB program was used to model and simulate the performance of the investigated two-stage adsorption chiller with and without heat recovery using an activated carbon/methanol pair. The simulated model results were then validated by the experimental results conducted by Millennium Industries. The model was based on 10th order differential equations; six of them were used to predict bed, evaporator and condenser temperatures while the other four equations were used to calculate the adsorption isotherm and adsorption kinetics. The detailed validation is stated in the next paragraphs; for example, it clearly notes that the simulation model results for the two-stage air cooled chiller are well compared with the experimental data in terms of cooling capacity (6.7 kW for the model compared with 6.14 kW from the experimental results at the same conditions). The Coefficient of Performance (COP) predicted by this simulation was 0.4, which is very close to that given by the Carnot cycle working at the same operating conditions. The model optimized the switching time, adsorption/desorption time and heat recovery time to maximize both cooling capacity and COP. The model optimized the adsorption/desorption cycle time (300 to 400 s), switching cycle time (50 s) and heat recovery cycle time (30 s). The temporal history of bed, evaporator and condenser temperatures is provided by this model for both heat recovery and without heat recovery chiller operation modes. The importance of this study is that it will be used as a basis for future series production.

This paper presents a simple mathematical and Simulink model of a two-phase hybrid stepper motor, where ignoring the permeance space harmonics of the hybrid stepper motor is regarded as the main physical assumption in this article. Moreover, the dq transformation method is adopted as the main mathematical approach for the derivation of the proposed model, where simple voltages, currents, and torque equations are obtained and used to build the proposed Simulink and circuit model of the stepper motor. The validity and the effectiveness of the proposed model are examined by comparing its results with the results collected from the Simulink model in the library of Matlab. The obtained simulation results showed that the proposed model achieved a high simplicity and high accuracy when compared with conventional models.

With the daily expansion of global energy consumption, developing the power grids is of uttermost importance. However, building a new transmission line is costly and time-consuming, so utilizing the same lines with possible higher transmission capacity is very cost-effective. In this regard, to increase the capacity of the transmission lines, the flexible alternating current transmission system (FACTS) has been widely used in power grids in recent years by industrialized countries. One of the essential topics in electrical power systems is the reactive power compensation, and the FACTS plays a significant role in controlling the reactive power current in the power grid and the system voltage oscillations and stability. When a static synchronous compensator (STATCOM) is embedded in a power system to increase the bus voltage, a supplementary damping controller can be designed to enhance the system oscillation damping. Given the expansion of the grids in the power system, the complexity of their optimization and the extraordinary ability of the imperialist competitive algorithm (ICA) for solving such problems, in this paper, the ICA has been used to determine the optimal position and size of the FACTS devices.

In this paper, the installation of energy storage systems (EES) and their role in grid peak load shaving in two echelons, their distribution and generation are investigated. First, the optimal placement and capacity of the energy storage is taken into consideration, then, the charge-discharge strategy for this equipment is determined. Here, Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) are used to calculate the minimum and maximum load in the network with the presence of energy storage systems. The energy storage systems were utilized in a distribution system with the aid of a peak load shaving approach. Ultimately, the battery charge-discharge is managed at any time during the day, considering the load consumption at each hour. The results depict that the load curve reached a constant state by managing charge-discharge with no significant changes. This shows the significance of such matters in terms of economy and technicality.