Energy Equipment and Systems
Volume:12 Issue: 1, Winter 2024

The collision of two spheroidal drops in a shear flow is simulated in this paper using the finite difference/front tracking method. The influences of deformability, initial offset, and the size of drops on their collision dynamics are assessed. It is demonstrated that the non-dimensional relative trajectory of a pair of drops, ∆z/R, is enhanced gradually as they approach and then, gains a maximum value and finally, reaches a new constant value after separation. An enhancement in the capillary number results in an increase in the deformation of the drops. The deformation and the time required for the collision of two drops are reduced as their initial offset is enhanced. It is revealed that as the ratio of major diameter to minor diameter of spheroidal drops is intensified, their deformation is enhanced.

Being inspired by nature and moving towards clean energy has become a very necessary and indispensable objective these days. By observing a collection of plants/vegetation growing underneath the rivers, oceans, and seas, the idea of designing a plant farm being capable of absorb fluid energy was born. The farm comprises numerous aluminum cantilever beams equipped with a piezoelectric layer in different shapes. The field has elements of different sizes and natural frequencies, where the maximum voltage can be obtained using the resonance phenomenon. Frequency of the fluid flow is considered, because it follows the oscillatory behavior of the wakes and vortices when the fluid passes through the obstacle. The Strouhal number helps to obtain the fluid frequency according to the fluid velocity and the characteristic length of the barrier. In this research, it was observed that the increase in the length of the aluminum layer caused a rise in the voltage generated. The triangular model produced a higher amount of voltage compared with the other three-dimensional models i.e. the rectangular, trapezoidal and triangular ones. Therefore, it was concluded that providing the farm with triangular elements with different dimensions is considered to be an effective and reasonable measure. Actually, having a variety of sizes of these elements covers a wide range of natural frequencies causing a higher number of them to be excited.

The novel tri-generation system powered by geothermal energy is assessed from exergo-economic and thermodynamic perspectives. The proposed system consists of a geothermal single flash cycle, an ORC with the OFOH and the IHE, a HDH desalination system, and a double-effect absorption refrigeration system. This system aims to produce power, cooling load, and the freshwater. The design parameters effects such as geothermal inlet temperature, the flash chamber inlet pressure, HPG temperature difference, and steam-turbine outlet pressure on the main indicators, including exergy efficiency, cooling load, total product unit cost, and produced freshwater mass flow rate. Moreover, the multi-objective optimization is applied using machine learning method and Grey wolf algorithm to optimize the total product unit cost, the net generated power rate, and the exergy efficiency. Under base design conditions, the total product unit cost and the exergy efficiency are 77.8 $/GJ and 44.2%, respectively. Moreover, the results for the exergy efficiency, the total product unit cost, and the net generated power rate of the system under multi-objective optimization are 54%, 62.5 $/GJ, and 180 kW. Among all elements of the current system, TEG1 has the greatest rate of the exergy destruction, which is 94.02 kW. Additionally, the rate of the overall system exergy destruction is 221.72 kW

In this study, frost-resistant regulators in terms of temperature and hydrodynamics in COMSOL Multiphysics software were investigated. The heat exchanger considered in this research was investigated from various aspects including changes in dimensions, location of the exchanger, the effect of changes in the temperature of the exchanger wall, as well as the effect of square and triangular fins. The results showed that by increasing the dimensions, both longitudinally and transversely, the efficiency of the heat exchanger increases. However, increasing the dimensions of the heat exchanger is slightly allowed due to limited space as well as the limitations of solid mechanics. Also increase the temperature of the heat exchanger wall causes Intense temperature gradients occur in the orifice area, which can be effective in melting the ice created in that wall. The presence of square and triangular fins can help increase efficiency and create a more intense temperature gradient in the orifice area. Square fins are more effective than triangular fins, although the maximum temperature difference in that area is about 3 Kelvin. The largest temperature gradient is between the temperature of the inlet gas and the temperature of the orifice bottleneck and is equal to 24 Kelvin. The maximum temperature of the heat exchanger wall is 523 K, which results in a temperature of 360 K in the orifice wall, which can lead to the melting of possible frost.

Intelligence and Smart power grids with the Demand Side Management (DSM) strategies enables Demand Response Strategies (DRS) that are especially used in residential districts. Plug-in hybrid electric vehicles (PHEVs), as another sort of load in the power system, have recently become increasingly popular as they provide an opportunity for customer benefits to reduce greenhouse gas emissions. Based on the level of introduction of PHEVs in the parking lot, charging behaviors in an area cause a change in the load profile of the power system. Therefore, it is necessary to examine the effect of the introduced level of PHEV on the load profile due to the expected charging behavior of residents. PHEVs also offer a variety of opportunities, including the ability to use EVs as storage units via vehicle-to-grid (V2G) options. In this paper, a joint evaluation of different DR techniques with a bilateral PHEV, energy storage system (ESS), and photovoltaic (PV) system is realized. Mixed integer Linear Programming (MILP) for a Home Energy Management (HEM) framework is proposed in this paper. A small-scale on-grid solar energy with a storage system and the V2G potential with different DR programs are all integrated into a single HEM system to select the most efficient and economical DR program.

The outcomes of every batch of anaerobic digesters vary due to differences in equipment, feed composition, and operating conditions. The performance of a bench-scale anaerobic digestion system was investigated in this study with the goal of biomethane production, considering mesophilic requirements at 37°C and thermophilic conditions at 57°C. Three experiments were carried out under mesophilic and thermophilic conditions. A blend of water and solid organic waste was used in the first experiment. The second test involved a mixture of water, material that had undergone prior digestion, and solid organic waste. The third trial incorporated water, previously digested material, solid organic waste, and cow manure as part of the feed. Based on the result, in the third experiment, over 32 days within mesophilic conditions, the average daily biogas and biomethane production per unit of feed mass was quantified as 1610 and 447.10 ml, respectively. Furthermore, the measurements indicated 62.22% and 99.99% increases compared to similar feed subjected to thermophilic conditions. Moreover, the data displayed growth rates of 8.05%, 96.04%, and a substantial rise of 69.47% and 147.7% compared to the outcomes of the second and third experiments performed under mesophilic conditions. Additionally, it can be included that the digestion period of the third test was 60 days shorter than that of the second and one day less than the first trial when operating under mesophilic conditions. As a result, the most effective method for anaerobic digestion involved blending solid organic waste, previously digested material, cow manure, and water under mesophilic conditions.