Theoretical and Experimental Performance Analysis of a Novel Domestic Biogas BurnerRead the full article
Journal of Energy publishes research relating to the science and technology of energy generation, distribution, storage, and management. It also covers the environmental, societal and economic impacts of energy use and policy.
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Investigation of Biogas Energy Yield from Local Food Waste and Integration of Biogas Digester and Baking Stove for Injera Preparation: A Case Study in the University of Gondar Student Cafeteria
Energy shortage is the main problem while preparing food at the university in Ethiopia. Baking of injera consumes a lot of firewood due to the nature of baking mitad and layout of the system. The daily average firewood consumption is 8600 kg which is equivalent to 790.3 m3 of gas. In this study, an investigation of energy yield from food waste is examined by assessing the daily waste generation rate from the university student cafeteria and configuring the baking stove (mitad) that utilizes biogas energy. CFD is used to investigate the performance and heat distribution of baking mitad. In the study, the measured average daily biodegradable food waste and kitchen waste generation rate in the campus is around 863 kg/day. The conversion of this food waste using the anaerobic digestion system yields 43.2 m3 biogas per day. Utilizing the daily biogas generated for baking injera improves the overall food making process and reduces firewood consumption by 5.4%. This biogas energy yield is considered to be utilized for baking injera in the kitchen. The designed biogas mitad (stove) does not generate smoke due to the type of fuel used and configuration of baking mitad. Furthermore, the stove has an insulation mechanism considered to conserve the heat loss to the surrounding. Generally, the utilization of the biogas system and integration of the biogas injera baking stove will improve the overall food processing mechanism in the university.
The Choice of Nuclear Energy for Ghana as a Result of Development of Its Energy Production
Ghana thought of nuclear energy early in the 1960s but has not been able to realize this dream of generating electricity from nuclear power. Ghana’s electricity generation dates back to the Gold Coast era where the main source of electricity supply (isolated diesel generators) was owned by industrial establishments, municipalities, and other institutions. The electricity sector has developed over the years and has diversified its power generation development to take advantage of available and sustainable sources of energy, mainly hydro, natural gas, liquefied petroleum products, and renewables. These sources sought to increase the electricity production capacity in the country, but unfortunately, it has not been able to catch up with the rate of economic growth, urbanization, industrialization, and rural electrification projects. This has led to Ghana’s persistent energy crisis, with inadequate and unpredictable power supply coupled with erratic and prolonged cuts of electricity to homes, industries, and businesses which is now colloquially referred to in the local parlance as “dumsor.” The Government of Ghana and key stakeholders have therefore decided to add nuclear energy to the energy mix of the country to complement the country’s two main energy sources being hydro and thermal electricity. The details of the developments in the electricity sector leading to the choice of nuclear energy as the best solution for Ghana have been outlined.
Thermal Performance Analysis of Solar Dryer Integrated with Heat Energy Storage System and a Low-Cost Parabolic Solar Dish Concentrator for Food Preservation
Solar energy has become a viable alternative energy because it is a clean type of energy that converts solar radiation into heat energy for various applications such as heating water, power generation, cooking, and food drying. The solar dryer, integrated with the heat energy storage system, uses nitrate salt as a heat storage medium which was designed and tested by drying 1000 grams of red pepper at 19.6 to 62.4°C. The average ambient temperature ranged from 19.3 to 37.4°C, and the maximum temperature of the heat storage media ranged from 87.8 to 125°C. The solar drying process was compared to open sun drying system loaded with 1000 grams of red pepper. The findings showed that the solar dryer maintained color and flavor and lowered the original moisture content from 86% to 10% for 24 hours compared to 36 hours of drying in open air. In this study, nitrate salt is shown to be the perfect heat storage medium for drying food products; it preserved heat for about 4 hours when there is no active sunlight.
A Structural Review of Thermoelectricity for Fuel Cell CCHP Applications
This article starts by introducing the ongoing South Africa electricity crisis followed by thermoelectricity, in which eighteen miscellaneous applicable case studies are structurally analysed in detail. The aim is to establish best practices for the R&D of an efficient thermoelectric (TE) and fuel cell (FC) CCHP system. The examined literature reviews covered studies that focused on the thermoelectricity principle, highlighting TE devices’ basic constructions, TEGs and TECs as well as investigations on the applications of thermoelectricity with FCs, whereby thermoelectricity was applied to recover waste heat from FCs to boost the power generation capability by ~7–10%. Furthermore, nonstationary TEGs whose generated power can be increased by pulsing the DC-DC power converter showed that an output power efficiency of 8.4% is achievable and that thicker TEGs with good area coverage can efficiently harvest waste heat energy in dynamic applications. TEG and TEC exhibit duality and the higher the TEG temperature difference, the more the generated power—which can be stabilised using the MPPT technique with a 1.1% tracking error. A comparison study of TEG and solar energy demonstrated that TEG generates more power compared to solar cells of the same size, though more expensively. TEG output power and efficiency in a thermal environment can be maximised simultaneously if its heat flux is stable but not the case if its temperature difference is stable. The review concluded with a TEC LT-PEM-FC hybrid CCHP system capable of generating 2.79 kW of electricity, 3.04 kW of heat, and 26.8 W of cooling with a total efficiency of ~77% and fuel saving of 43.25%. The presented research is the contribution brought forward, as it heuristically highlights miscellaneous thermoelectricity studies/parameters of interests in a single manuscript, which further established that practical applications of thermoelectricity are possible and can be innovatively applied together with FC for efficient CCHP applications.
Cryptogamic Packed Biofilter as Potential Adsorbent for CO2, NH3, and H2S Impurities from Biogas
The presence of elevated concentrations of carbon dioxide, hydrogen sulfide, ammonia, and trace impurities in biogas affect its caloric value as well as causes corrosion and is extremely toxic. There are various methods in existence for removal of these impurities, but most are chemically based and expensive and are limited in use. In our work, cryptogams (moss) integrated with soil and biochar packed in a filter have been employed for simultaneous removal of CO2, H2S, and NH3, from biogas. Different soil types rich in metallic oxides at different masses of 100 g, 150 g, and 200 g with a fixed mass of moss and biochar were tested in an on-site experiment to determine the removal efficiency (RE) and sorption capacity (SC). The adsorption dynamics of the filters were investigated at two flow rates, 80 ml/min and 100 ml/min, by determining removal efficiency. For the contribution of each substrate, sorption capacity and breakthrough time were determined by considering 5 g of each substrate that made up the filter. The soils with a high content of extractable cations showed excellent adsorption capacity for H2S by about 20 g S/100 g, which was higher than other adsorbents tested. It was found that integrated biofilter made up of bed arrangement of the soil, biochar, and moss plant improved the quality of biogas with SC of 11 g S and RE of 93% for H2S, 72% for NH3, and 68% for CO2.
The Research on Characteristics of Li-NiMnCo Lithium-Ion Batteries in Electric Vehicles
The energy density of canode materials for lithium-ion batteries has a major impact on the driving range of electric vehicles. In order to study the charge-discharge characteristics and application feasibility of Li-NiMnCo lithium-ion batteries for vehicles, a series of charge and discharge experiments were carried out with different rates of Li-NiMnCo lithium-ion batteries (the ratio of nickel, cobalt, and manganese was 5 : 2 : 3) in constant-current-constant-voltage mode. Firstly, a set of charge-discharge experiments were performed on different types of single-cell lithium-ion batteries. The results show that, under temperature conditions, the charge and discharge voltage-capacity curves of the four different types of Li-NiMnCo lithium batteries mentioned in the paper are not much different, and the charge-discharge characteristic curves are similar, indicating that different types of batteries with the same material composition have similar charge and discharge characteristics. Subsequently, a series of charge and discharge tests with different rates were conducted on such ternary lithium batteries. The characteristic curves with different charge-discharge rates indicate that this new type of ternary lithium battery has high current charge and discharge capability and is suitable for use in new energy electric vehicles. In addition, by analyzing the voltage-SOC curve under different magnification conditions, it is known that there is an approximate linear relationship between the battery voltage value and the SOC within a certain SOC range. The SOC value can be evaluated by the battery voltage, which should be controlled within a reasonable range to avoid overcharge or overdischarge of battery, thereby, causing permanent damage to the battery.