• Energy Research

Paddy drying is an energy-intensive process that influences the quality of rice. In the present study, a pilot-scale reversible flatbed dryer operated with biomass gasifier was designed and constructed to dry the soaked paddy with high moisture content (38 % w.b.) in the parboiling process. The paddy dryer has a maximum designed capacity of 30 kg/batch. The performance of the dryer along with the main components of the system is evaluated using the exergy analysis method for the optimal operating condition of 75 °C drying air temperature and 0.12 m/s drying air velocity. The Hot Air Generator (HAG) is found to be the most important component for improving the system efficiency followed by the scrubber and gasifier. The Grassmann diagram for the overall drying system is also presented to quantify the exergy loss from the various components of the system components. The exergetic factor (f) and the Sustainability Index (SI) of the system components are calculated to indicate the quantity of exergy handled and environmental sustainability respectively. The gasifier unit accounts for more than 60 % amount of the total exergy of the system. The exergy efficiency is found to be 70.929 % for gasifier, 62.411 % for scrubber, 35.288 % for HAG, 11.30-76.65 % for drying cabinet with an average value of 34.81 %, and 5.267-14.44 % for the overall drying system. The average exergy efficiency of the overall drying system is found as 21.28 % respectively.

The milk processing and preservation is a fast growing business in developing countries and it is facing problems due to high energy cost and environmental concerns in using conventional energy sources. The energy tapped from renewable energy sources through the technological innovations would be one of the best options to implement the milk preservation strategies at village level. In rural areas, bioenergy is one of the most versatile energy-generating options. Because of the diversity in feed stock and conversion technologies, suitable study is needed to implement renewable energy base technologies to provide a continuous flow of energy services. In this paper, the use of locally available renewable energy sources, in various combinations, to operate a milk chilling plant at village level has been analysed using the Matlab software. The effect of variations in the combination of renewable energy sources on the overall system COP has been studied. The study predicts that the best possible overall system COPs in hilly, rubber cultivation, paddy and seashore regions are 0.26, 0.25, 0.235 and 0.24 respectively. Moreover, suitable combinations identified in the aforementioned regions are Biomass/Gobar gas (0.7:0.3), Biomass/Biogas/Gobar gas (0.7:0.1:0.2), Biogas/Biomass/Gobar gas (0.6:0.15:0.25) and Biomass/Gobar gas/Biogas/Solar (0.5:0.25:0.125:0.125) respectively.

Abstract In the commercial food sector, preservation and transportation is responsible to avoid the 22% spoilage of the total food production in developing countries like India. To reduce the spoilage, preservation of such produce including milk is needed in remote places. Due to the increased fossil fuel costs, issues in grid extension and environmental concerns, there has been a renewed interest in hybrid renewable energy systems for cooling applications in remote/rural areas. In this paper, the overall thermal performance and economic aspects of a hybrid energy based milk cooling system for hilly terrain have been analysed using the MATLAB software and the appropriate hybrid energy systems has been predicted. The results indicate that the biomass and gobar gas combination can show the overall thermal performance as 0.17–0.23 with lowest Payback period and life cycle cost of 4.5 years and INR 2.8 × 10 7 respectively. The sensitivity analysis shows that the maximum influence of uncertainty in input parameters on the overall COP, capital cost, running cost and payback period are 6.8, 5.1, 5.3 and 6.1 percentages respectively.

Direct firing of biomass in conventional clay brick manufacturing process aggravates deforestation, climatic change, poor economic benefits to rural industries, and health issues to the public. To overcome such drawbacks, adaptation of eco-friendly energy sources, implementation of advanced technologies in energy conversion systems and systematic studies on economic benefits are mainly focused in recent times. The utilization of biomasses through various gasification technologies can improve the energy efficiency and economic advantages of brick production. To successfully introduce renewable energy systems and new technologies in rural areas, a number of research studies have experimented and also succeeded in predicting the technical feasibility and cost benefits. Likewise, this paper reports the techno-economic analysis of producer gas (PG) fired brick kilns using pertinent parameters of evaluation involved in the manufacturing of bricks. In this study, the common biomasses available in the region were effectively used to produce PG. Besides finding the technical aspects of bricks produced through this method, the parameters needed for economic study were found from a prototype experimental study. The economic parameters to use agriculture and forestry biomasses such as Coconut Shell (CS), Rice Husk (RH), Rubber Wood (RW) and Rubber seed kernel shell (RSKS) in conventional industries for a capacity of twenty to one hundred thousand bricks per batch were predicted. The studies revealed that the quality of bricks produced from the proposed method could meet ASTM standards. The savings in the running cost of the proposed system led to 4–8 years payback period. The maximum internal rate of return was found from the system which had RSKS as feedstock.

Hydrogen production from biological processes has been hailed as a promising strategy for generating sustainable energy. Fermentative hydrogen production processes such as dark and photofermentation are considered more sustainable and economical than other biological methods such as biophotolysis. However, these methods have constraints such as low hydrogen yield and conversion efficiency, so practical implementations still need to be made. The present review provides an assessment and feasibility of producing biohydrogen through dark and photofermentation techniques utilizing various lignocellulosic biomass wastes as substrates. Furthermore, this review includes information about the strategies to increase the productivity rate of biohydrogen in an eco-friendly and sustainable manner, like integration of dark and photofermentation techniques, pretreatment of biomass, genetic modification of microorganisms, and application of nanoadditives.

Ice is commonly used as a major essential product for fish preservation, and it is produced by energy-intensive ice-making plants in the form of ice blocks weighing 130–150 kg. As an initiative for shifting toward renewables, a biomass gasifier for power generation systems in ice plants is a technology that has to be investigated. The purpose of this investigation is to study the techno-economic parameters involved in implementing a biomass power generation system (BPGS) for ice plants that have been identified in the study area that produces 5–100 tons of ice per day (TPD). Rice husk, coconut shell, and rubber shell are recognized as the significant biomass resources identified within the study area that can be used for producer gas generation for dual fuel application in a diesel engine as a secondary fuel. Among the three feedstock, the rubber shell fueled BPGS system showed the highest overall efficiency from 15.8% to 25.7%, diesel savings from 48.04% to 77.86%, and minimum biomass consumption from 91.72 to 733.75 kg/h. Economic indices like operating cost (OC), payback period, and life cycle cost are with range from Indian Rupee (INR) 30.51 to 174.44 × 106, 1.79 to 5.8 years, and INR 1.65 to 9.53 × 108, respectively. Positive net present value is observed for the capacities above 37 TPD for rubber shell powered BPGS. The sensitivity analysis shows that the maximum influence of uncertainty in input parameters on the Investment cost, OC, and payback duration are 10.26%, 6.3%, and 12.29%, respectively.

The scarcity of conventional energy sources and their environmental impacts have led to successful implementation of biogas technologies in various applications. However, the lack of awareness in the society and economic viability are a few constraints that hinder the effective use of biogas in many sectors. Therefore, intensive research is needed to overcome the above said issues and extend the use of biogas into many newer avenues. Academic institutions are the places where people have more awareness on the environmental impacts. However, the nonuniform availability of biowastes and the lack of studies on the economic benefits of this technology restrict the implementation of the same. This study focuses on the economic benefits of implementing three types of biogas digesters, KVIC, JANATA, and Fiber‐glass reinforced polyester biogas plants, in five different academic institutions where the student population and generation of biowastes throughout a year are nonuniform, and the digester may not run with full load continuously. Based on a pilot study, the quality and quantity variations because of the nonuniform strength of student during a year have been studied and the same have been used to predict the biogas generation in the selected institutions. The result shows that biogas energy production is economically viable for capacities ranging from 25 to 450 m3 with a payback period between 3.18 and 7.59 years for various types used in the study. The economic viability of the biogas plants is proved with positive net present value. © 2018 American Institute of Chemical Engineers Environ Prog, 37: 1901–1907, 2018

Adsorption-based cooling system is a cost-effective method of heat conversion. It has the potential to dramatically enhance energy efficiency while also lowering pollutant levels. For this purpose, a solar-powered vapor adsorption refrigeration system (VAdRS) using activated carbon–methanol and zeolite–water as the working pair has been designed and experimentally evaluated. The aim of this experiment was to evaluate the coefficient of performance (COP) and specific cooling power (SCP) of a solar cooling unit by utilizing the optimum minimum and maximum mass concentration ratios. The novel solar-assisted adsorption refrigeration system optimization technique is used in this research to evaluate the optimal performance of the solar-powered VAdRS under various operating scenarios. The experiment was conducted at the optimum minimum and maximum mass concentration ratios of 0.1 and 0.2, respectively. The experimental results show that the activated carbon–methanol adsorption system produces a higher COP value than the zeolite–water adsorption system of 0.49–0.64 and 0.64–0.67 at constant evaporator and condenser temperature, respectively. It also showed that the higher SCP value was revealed in the zeolite–water-based adsorption cooling system as 207.5–217.4 kJ/kg. It was revealed that AC–methanol could be used to operate better in low-generating-temperature conditions. On the other hand, the zeolite–water adsorption system can be used at higher generating temperatures.