Exergy analysis of energy-intensive production processes: advancing towards a sustainable chemical industry

Exergy analysis is becoming a very powerful strategy to evaluate the real efficiency of a process. Its application in the chemical industry is still at an early stage but many interesting remarks can be obtained from the recent research in the most energy intensive processes of the chemical industry: the production of chemicals, the cement industry, the paper industry and, the iron and steel industry. The present review analyzes the opportunities and challenges in those sectors by considering exergy analyses as the first required step (although not sufficient) to advance towards a more sustainable chemical industry. Social, environmental and economic factors play a role in the critical evaluation of a process and exergy could be considered as the property that joins together those three cores of sustainability

A review on exergy analysis of biomass based fuels

Renewable energy sources can be a good substitute of the fossil fuels which are being terminated fast. Nowadays biomass and biofuels are considered because of their environment friendly characteristics and their ability of supplying much more energy. An alternative means to select the most efficient and convenient biomass, is exergy analysis. The present paper has reviewed the existent surveys on the exergy analysis of different kind of biomass included the woody biomass, herbaceous and agricultural biomass, aquatic biomass, contaminated biomass and industrial biomass. The most common thermochemical processes are investigated and the efficiency of the different process and various kinds of biomass are determined

Energy, exergy and environmental analysis of cold thermal energy storage (CTES) systems

As the air conditioning system is one of the largest contributors to electrical peak demand, the role of the cold thermal energy storage (CTES) system has become more significant in the past decade. The present paper has reviewed the studies conducted on the energy and exergy analysis of CTES systems with a special focus on ice thermal and chilled water storage systems as the most common types of CTES. However, choosing a proper CTES technique is mainly dependent on localized parameters such as the ambient temperature profile, electricity rate structure, and user's habit, which makes it quite difficult and complicated as it depends on many individual parameters. Therefore, it was found that energy and exergy analysis can help significantly for a better judgment. The review paper has shown that the exergetic efficiency analysis can show a more realistic picture than energy efficiency analysis. In addition, the environmental impact and the economic feasibility of these systems are also investigated. It was found that, based on the total exergy efficiency, the ice on coil (internal melt) is known as the most desirable CTES system

An inverse method for optimization of geometric parameters of a Savonius-style wind turbine

© 2017 Elsevier Ltd This work is aimed at optimizing the dimensions of a semicircular-bladed Savonius Style Wind Turbine (SSWT) using Differential Evolution (DE) based inverse optimization methodology to simultaneously satisfy a given power and torque characteristics. The results obtained from the inverse analysis are well-validated with the experimental wind tunnel results available under different wind speeds. The effect of necessary blockage corrections is considered. Using DE-assisted inverse method, the present study demonstrated smaller turbine dimensions than those reported in various literature and also yields a lower value of the blockage ratio. The overall area of the SSWT is found to be reduced upto 9.8% with respect to the corresponding experimental wind tunnel data. The improvement is attributed due to an optimized interplay between multiple combinations of parameters satisfying a given power and torque. To achieve a given power and torque requirement under a given range of tip speed ratio, it appears from the study that the blade overlap can be significantly regulated through minor adjustments of the chord length and turbine height. The sensitivity analysis reveals that the aspect ratio governing parameters such as turbine height and chord length are critical factors governing the torque and power output from SSWTs. In order to meet a desired power and torque, the present study offers a novel inverse methodology aided by the DE algorithm to simultaneously estimate and optimize geometric parameters of SSWT. The benefit of this work is to provide an alternative and optimized solution to the existing literature data where the overall area of SSWT can be reduced and significant material along with space savings can be accomplished