Energy Conversion

Pemahaman tentang biomassa dapat diawali dengan pengertian, kemudian melangkah ke identifikasi tipe, sumber, karakteristik, target pengunaan, teknologi konversi, mata rantai penyediaan bahan baku mulai dari sumber hingga ke pabrik pengolahnya, strategi dan langkah taktis untuk mendayagunakan biomassa sebagai bahan baku bioenergi.

Melalui artikel ini akan disajikan kerangka pikir penulis dalam mempelajari biomassa sebagai sumber bahan baku energi terbarukan dan teknologi konversinya.

This research was funded by, and implemented within, a UK national research organisation, while the author was the KE and Impact Evaluation Manager responsible for assessing impact on a £15m UK government-funded research programme.

This work was also submitted as the authors MBA dissertation which was accepted and awarded in 2009.

ABSTRACT: A methodology and methods ‘toolbox’ is proposed for conducting impact research and assessment from within research programmes. The emphasis is upon how to clarify and assess the wider impacts from the early stages onwards.

The approach explicitly acknowledges, and attempts to address, the known issues and challenges of impact assessment while drawing upon the resources and opportunities available to research managers and researchers within such programmes.

The study has two triangulating foundations. Firstly, it examines the academic literature to help identify and design the pilot methodology and methods. Secondly it trials these in a real programme to both test and improve them.

The study was conducted over one year within one leading UK research organisation, where two research programmes (and around 60 research projects of £15m total value) were being assessed for their impacts. The study draws upon actual impact management experience and reflection, prospective (ex ante) and retrospective (ex post) assessments, participatory contributions from leading researchers undergoing assessment, and consultation with external users. The findings of this study outline the pilot and its first iteration. Recommendations are made for improvement to the methodology and methods.

A subsequent follow-on bid to UK government incorporating the impacts identified from implementing this methodology, successfully led to a further £15m of government funding.

It is expected the pilot methodology and methods will be applicable to other organisations, conducting and funding such research programmes, required to research and assess the wider research impacts.

Although primary focus of implemetation trials was upon research in physical sciences, technology, high-tech engineering, computing/IT, and environment, the wider literature study, the methodology design and justification, the methods proposed and used, and the resulting general recommendations and lessons are expected to apply more broadly to many other research areas, where the impact is to be found more widely in the society, economy, government or public sector or within organizations, policies, professions or the public.

Interest in this work is expected from research programme managers, impact managers and assessors, management consultants advising in this area, and government funding managers, all seeking to embed a developing approach to understand, capture, and enhance wider impact.

This paper proposes a new, simple, yet accurate mechanical cooling tower model for the purpose of energy conservation and management. On the basis of Merkel’s theory and effectiveness-NTU method, the model is developed by energy balance and heat, mass transfer analysis. Commissioning information is then used to identified, only three model parameters by Levenberg–Marquardt method. Compared with the existing models,

Today, energy crisis turn out to be a serious threat towards sustainability for developing countries since their energy demand is growing more rapidly than developed countries. On the other hand, fossil fuels cannot sustain anymore in the near future because of environmental impacts and depletion of the reserves. Malaysia is experiencing drastic growth in population and economy and requires exploring alternative energy sources to support its population and commercial energy demand. Biomass as the fourth largest energy resource in the world is abundant in the country. Malaysia is blessed with tropical and humid climate all year round which is a magnificent opportunity for fully exploiting agriculture and tropical forests potential. Since late 1990, the concept of waste-to-wealth had been promoted and became popular widely. This concept is based on unwanted wastes which are converted into valuable energy while reducing waste generated and increase the economy-efficiency mainly used for cooking, space heating and power generation. Currently, concerted efforts and various biomass energy programs are supporting by the government for development, demonstration and commercialization. This paper intent to present the current state and prospects of biomass utilization and strategies promoted for future developments in Malaysia.

http://www.sciencedirect.com/science/article/pii/S1364032111001535

Today, the whole world faces a great challenge to overcome the environmental problems related to global energy production. Most of the islands throughout the world depend on fossil fuel importation with respect to energy production. Recent development and research on green energy sources can assure sustainable power supply for the islands. But unpredictable nature and high dependency on weather conditions are the main limitations of renewable energy sources. To overcome this drawback, different renewable sources and converters need to be integrated with each other. This paper proposes a standalone hybrid photovoltaic- (PV-) wave energy conversion system with energy storage. In the proposed hybrid system, control of the bidirectional buck-boost DC-DC converter (BBDC) is used to maintain the constant dc-link voltage. It also accumulates the excess hybrid power in the battery bank and supplies this power to the system load during the shortage of hybrid power. A three-phase complex vector control scheme voltage source inverter (VSI) is used to control the load side voltage in terms of the frequency and voltage amplitude. Based on the simulation results obtained from Matlab/Simulink, it has been found that the overall hybrid framework is capable of working under the variable weather and load conditions. © 2014 Nahidul Hoque Samrat et al.

http://www.hindawi.com/journals/tswj/2014/436376/abs/ 
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4032688/pdf/TSWJ2014-436376.pdf

Finding new energy sources is an important challenge of our times. A lot of research focuses on identifying such sources that can also be exploited with relatively simple and efficient systems. These sources can be either new materials that can be used to generate energy, or solutions to scavenge already existing forms of energy. Part of the latter class of solutions, the system presented in this paper converts the energy consumed by many people in gyms (or even at home, during exercise) into electric energy. This energy exists anyway, because people want to be healthier or to look better. Currently, this significant (in our opinion) amount of energy is actually wasted and transformed into heat. Instead, in this study, a prototype scavenging system (dedicated to fitness/stationary bikes) to collect and (re)use this energy is presented. Specifically, we depict the design of a low-budget system that uses existing, discrete components and is able to scavenge some of the energy spent by the biker. The experimental results show that the system is functional, but its efficiency is limited by (mechanical) losses before the collection.

The sugarcane industry represents one of the most important economic activities in Brazil, producing sugar and ethanol for the internal and external markets. Moreover, thermal and electric energy is produced for self-consumption, using sugarcane bagasse as fuel in cogeneration plants. Almost all the sugarcane plants in Brazil are self-sufficient in terms of energy supply and in the last few years some of them have been selling their surplus electricity for the grid. The reduction of process steam requirements and the use of more efficient cogeneration systems are new alternatives to increase the surplus electricity generation. The purpose of this paper is to analyze the steam
demand reduction on sugar and ethanol process and alternatives for cogeneration systems in sugarcane plants, aiming at the surplus electricity generation increase.
.

Conversion of waste heat to voltage has the potential to significantly reduce the carbon footprint of a number of critical energy sectors, such as the transportation and electricity generation sectors, and manufacturing processes. Thermal energy is also an abundant low-flux source that could be harnessed to power portable/wearable electronic devices and critical components in remote off-grid locations. As such, a number of different inorganic and organic materials are being explored for their potential in thermoelectric energy harvesting devices. Carbon-based thermoelectric materials are particularly attractive due to their use of non-toxic, abundant source materials, their amenability to high-throughput solution-phase fabrication routes, and the high specific energy (i.e. Watts/gram) enabled by their low mass. Single-walled carbon nanotubes (SWCNTs) represent a unique one-dimensional carbon allotrope with structural, electrical, and thermal properties that enable efficient thermoelectric energy conversion. Here, we provide a detailed review of the progress made towards understanding the fundamental thermoelectric properties of SWCNTs, nanotube-based composites, and thermoelectric devices prepared from these materials. This progress illuminates the tremendous potential that carbon nanotube-based materials and composites have for producing high-performance next-generation devices for thermoelectric energy harvesting.

The aim of this study was to determine energy consumption of input and output used in pomegranate production in Antalya, Turkey. The data for the production of pomegranate were collected from 85 pomegranate farms by using a face-to-face questionnaire method in 2007 production period. In the study, energy values were calculated by multiplying the amount of inputs and outputs by the related energy conversion factors. The results indicated that total energy inputs were 53,764.63 MJ ha -1 . About 40% of this was generated by chemical fertilizers and 37% from chemicals. About 84% of the total energy inputs used was indirect and 89% of the total energy inputs used non-renewable energy in pomegranate production. The net energy and energy productivity values were estimated to be 2275.37 MJ ha -1 and 0.43 respectively, and the ratio of energy outputs to energy inputs was 1.04.

High temperature steam gasification is an attractive alternative technology which can allow one to obtain high percentage of hydrogen in the syngas from low-grade fuels. Gasification is considered a clean technology for energy conversion without environmental impact using biomass and solid wastes as feedstock. Sewage sludge is considered a renewable fuel because it is sustainable and has good potential for energy recovery. In this investigation, sewage sludge samples were gasified at various temperatures to determine the evolutionary behavior of syngas characteristics and other properties of the syngas produced. The syngas characteristics were evaluated in terms of syngas yield, hydrogen production, syngas chemical analysis, and efficiency of energy conversion. In addition to gasification experiments, pyrolysis experiments were conducted for evaluating the performance of gasification over pyrolysis. The increase in reactor temperature resulted in increased generation of hydrogen. Hydrogen yield at 1000 °C was found to be 0.076 ggas gsample−1. Steam as the gasifying agent increased the hydrogen yield three times as compared to air gasification. Sewage sludge gasification results were compared with other samples, such as, paper, food wastes and plastics. The time duration for sewage sludge gasification was longer as compared to other samples. On the other hand sewage sludge yielded more hydrogen than that from paper and food wastes.

In this paper, “energy efficiency” studies, done in a big industrial facility’s pumps, are reported. For this purpose; the flow rate, pressure and temperature have been measured for each pump in different operating conditions and at maximum load. In addition, the electrical power drawn by the electric motor has been measured. The efficiencies of the existing pumps and electric motor have been calculated by using the measured data.Potential energy saving opportunities have been studied by taking into account the results of the calculations for each pump and electric motor. As a conclusion, improvements should be made each system. The required investment costs for these improvements have been determined, and simple payback periods have been calculated.The main energy saving opportunities result from: replacements of the existing low efficiency pumps, maintenance of the pumps whose efficiencies start to decline at certain range, replacements of high power electric motors with electric motors that have suitable power, usage of high efficiency electric motors and elimination of cavitation problems.

Cocoa pod husks are generated in Côte d’Ivoire, in abundant quantities annually. The majority is left as waste to decompose at the plantations. A review of the ultimate and proximate composition of CPH resulted in the conclusion that, CPH is a high potential feedstock for both thermochemical and biochemical processes. The main focus of the study was the utilization of CPH in 10,000 tons/year power plants for generation of energy and value-added by-products. For this purpose, the feasibility of five energy conversion processes (direct combustion, gasification, pyrolysis, anaerobic digestion and hydrothermal carbonization) with CPH as feedstock, were investigated. Several indicators were used for the review and comparison of the technologies. Anaerobic digestion and hydrothermal carbonization were found to be the most suitable conversion processes. For both technologies an analysis was conducted including technical, economic, environmental and social aspects. Based on the characterization of CPH, appropriate reactors and operating conditions were chosen for the two processes. Moreover, the plants were chosen to be coupled with CHP units, for heat and power generation. After the evaluation and calculation of the main products and by-products that can be obtained, an economic analysis was conducted. Most of the electricity was assumed to be sold to grid (0.10 USD/kWh), after self-utilization, and the by-products were assumed to be sold as bio- fertilizers or soil conditioners, in both cases. The prices suggested for the by-products were estimated based on their nutrient content. For the economic analysis, total investment costs, running costs, revenues and more economic indicators were obtained and calculated. Both case study plants were found to be economically feasible (NPV>0). After comparing the NPV values, hydrothermal carbonization had higher NPV value, meaning it is more profitable. Though, there are many more barriers to overcome for hydrothermal carbonization than for anaerobic digestion. Moreover, the two case study plants can help with GHG mitigation, since 1,760 - 1,980 tCO2 eq/year can be avoided. Furthermore, several social benefits were identified. In conclution, hydrothermal carbonization and anaerobic digestion plants, utilizing CPH for energy conversion are feasible and cost viable solutions. Although, the governmental support can reduce the risks by assisting in the promotion of the by-products markets.