• Energy Research

Abstract Hydrokinetic turbine (HKT) generates electricity from the kinetic energy of flowing water and is suitable for energizing remote communities living in the proximity of rivers or canals. In this paper, a procedure for sizing components of a standalone hybrid energy system involving hydrokinetic turbine, photovoltaic and battery storage system is explained. Appropriate choices of optimum number and size of HKT modules, PV array capacity and minimum storage requirement are essential for the success of HKT-PV-battery system. The hydrokinetic turbine is modelled as a Savonius turbine and the performance parameters are established using ANSYS. Determination of the system design space is explained with an illustrative example, based on a time series simulation of the entire system. The sizing curve of the hybrid system is generated by plotting the PV array rating vs storage capacity diagram for a specified number of HKT modules. A parametric study of hydrokinetic turbine is conducted to generate a set of sizing curves and the best system configuration is identified.

The ever increasing demand for energy has necessitated exploring innovative techniques for low and medium temperature energy extraction. Among them, Kalina cycle is considered efficient for extracting energy from low grade renewable sources like solar, geothermal and for waste heat recovery. In this work, we propose a Kalina cycle with turbine staging and heating between the stages. A case study is presented to illustrate the cycle. The cycle is analysed for varying pressure in the second separator and mass fraction of vapour from the first separator. The dependency of variables on separator temperature, vapour fraction at the turbine exit, net work output of the cycle, net heat input of the cycle and efficiency are analysed. Optimisation of efficiency with second separator pressure and mass fraction of vapour at the first separator as variables has been carried out using Genetic Algorithm. The optimised efficiency for the illustrative example shows an improvement of 4% compared to a simple Kalina cycle with same input parameters.

A novel hybrid energy storage method is proposed in this paper to overcome high temperature levels at the start of the reaction in thermochemical energy storage, which causes this technology to be ...

Total site integration offers energy conservation opportunities across different individual processes and also to design as well as to optimize the central utility system. In total site integration of the overall process, indirect integration with intermediate fluids or through a central utility system are preferred as it offers greater advantages of flexibility and process control but with reduced energy conservation opportunities. To achieve the maximum possible indirect integration between processes assisted heat transfer, i.e., heat transfer outside the region between process pinch points, plays a significant role. A new concept is proposed in this paper for total site integration by generating a site level grand composite curve (SGCC). Proposed SGCC targets the maximum possible indirect integration as it incorporates assisted heat transfer. In this paper, a methodology is proposed to estimate the cogeneration potential at the total site level, utilizing the concept of multiple utility targeting on the SGCC. The proposed methodology to estimate the cogeneration potential is simple and linear as well as utilizes the rigorous energy balance at each steam header.

A three-dimensional steady state CFD model was developed in ANSYS-Fluent CFD solver to analyze heat transfer capability as well as the wall temperature distribution along the lateral walls of thermosyphon. The physical properties of the fluid and other formulations were taken from the literature to perform the analysis. The CFD simulation predicted the temperature and pressure profile of liquid vapor mixture as well as the distribution of temperature over an entire wall of the thermosyphon for various operating conditions like heat transfer rates and inclination angles. The model was also validated with available experimental results.The CFD simulation helped to visualize the steady state wall temperatures over the entire wall of the two-phase closed thermosyphon (TPCT) the first time which is very difficult to find out by experiments. The influence of inclination angle on the wall temperatures distribution of the lateral surface of the thermosyphon was also analyzed. An optimum inclination angle for heat flux and filling ratio was determined by comparing thermal resistances values.