P Padmanathan

Bio: P Padmanathan is an academic researcher from VIT University. The author has contributed to research in topics: Heat exchanger & Heat recovery ventilation. The author has an hindex of 1, co-authored 2 publications receiving 3 citations.

Multiphase numerical analysis of heat pipe with different working fluids for solar applications

Abstract: Energy crisis is a prognosis predicted in many cases with the indiscriminate encroachment of conventional energy sources for applications on a massive scale. This prediction, further emboldened by the marked surge in global average temperatures, attributed to climate change and global warming, the necessity to conserve the environment and explore alternate sources of energy is at an all-time high. Despite being among the lead candidates for such sources, solar energy is utilized far from its vast potential possibilities due to predominant economic constraints. Even while there is a growing need for solar panels at more affordable rates, the other options to harness better out of sun's energy is to optimize and improvise existing technology. One such technology is the heat pipe used in Evacuated Tube Collectors (ETC). The applications of heat pipe have been gaining momentum in various fields since its inception and substantial volumes of research have explored optimizing and improving the technology which is proving effective in heat recovery and heat transfer better than conventional systems. This paper carries out a computational analysis on a comparative simulation between two working fluids within heat pipe of same geometry. It further endeavors to study the multiphase transitions within the heat pipe. The work is carried out using ANSYS Fluent with inputs taken from solar data for the location of Vellore, Tamil Nadu. A wickless, gravity-assisted heat pipe (GAHP) is taken for the simulation. Water and ammonia are used as the working fluids for comparative multiphase analysis to arrive at the difference in heat transfer at the condenser section. It is demonstrated that a heat pipe ETC with ammonia as working fluid showed higher heat exchange (temperature difference) as against that of water as working fluid. The multiphase model taken aided in study of phase transitions within both cases and supported the result of ammonia as fluid being a better candidate.

A comprehensive review on optimization of hybrid renewable energy systems using various optimization techniques

Abstract: The increasing energy prices and pollutants from fossil fuels that threaten the climate, there is a growing preference for renewable energy. The implementation of hybrid renewable energy systems (HRES) has been a challenging task due to its interference, uncertainty, and unpredictable nature. Also, it comes with high net present cost and multi-dimensional architecture facets. It is critical to evaluate HRES using a variety of economic and sizing criteria. This paper aims to provide a succinct review of recent progress in the field of optimization of different HRES using various optimization techniques based on classical methods, artificial intelligence (AI), hybrid algorithms, and software-based optimization tools. While comparing classical and AI-based techniques, the AI-based techniques are found promising and provide a global solution in less time. However, there are deficiencies in AI-based techniques. To overcome those, a combination of two or more algorithms, known as hybrid optimization algorithm can be adopted to solve problems more quickly, reliably, and effectively. Apart from different algorithms, there are several popular optimization software tools. Among them, the HOMER software tool is one of the most popular as it is simple to use. As the research activities in the optimization of HRES are increasing, the concentration on sources such as hydro, geothermal, biomass, and biofuel has to be given due consideration. This analysis will inform readers about the current and evolving state of optimization approaches for HRES applications and enable them to choose the most appropriate strategy as per requirement.

Techno-economic analysis of a PV system with a battery energy storage system for small households: A case study in Rwanda

Abstract: Due to the inadequacy of distribution networks in developing countries, especially in small residential areas, there are frequent interruptions in the electrical energy provided by the grid. This problem negatively affects the life quality and productivity of the people living in these regions. This problem can be overcome by integrating BESS-supported renewable energy sources into the distribution system. These distributed energy resources contribute significantly to providing energy directly to consumers. On a small scale, such a system is supported by the grid, when possible, to ensure energy supply continuity. This study presents a techno-economic analysis, using PV*SOL simulation software, of a grid-connected solar PV system with BESS that is used to supply a small residential community in Rwanda, Muhanga district, Shyogwe sector. The consumers were a group of one hundred households around a wetland valley. The energy generated from the solar PV system was used to supply home appliances and a water pumping system for agricultural activities. The simulation results showed that the annual energy requirement is 82.34 MWh with a peak load of 30.4 kW. The simulation results also revealed that a PV system, with an installed capacity of 57.33 kWp integrated with a BESS of 89.2 kWh storage capacity, can supply the load with own power consumption of 68.65%, a level of self-sufficiency of 64.38%, and a performance ratio of 86.05% when the desired ratio is set to 110% with a year as the reference period. The financial analysis demonstrated a return on assets of 9.14% and an amortization period of 9.65 years. These results indicate that the proposed method is technically and economically feasible for use in addressing the issue of electrical power outages in developing countries.

Study of Heat Pipe Thermal Performance with Internal Modified Geometry

Abstract: The aim of this study was to investigate the effect of inserting a new internal tube packing (TP) on the thermal performance of a thermosyphon heat pipe (THP). The THP pipe was made from copper with an inner diameter of 17.4 mm and length of 600 mm. The new internal tube packing (TP) had a central copper disc with two copper tubes soldered onto both sides to transport vapor and condensate. The upper tube or riser had an inner diameter of 8.3 mm and was 300 mm long; it was connected to a hole in the disc from the upper side to transport the steam to the condenser section. The lower tube or downcomer had an inner diameter of 5 mm, was 225 mm long and was connected to the lower side of the disc to collect the condensate and transport it to the evaporator. The TP was inserted inside the THP to complete the design of the improved heat pipe (TPTHP). Experimental results showed that the TPTHP reduces the transit time from 16 to 11 min and the thermal resistance by 17–62% based on the input power and depending on the conditions of the THP. The results also showed that the inclination angle and filling ratio have no effect on the thermal resistance of the TPTHP.