Volume 3 Issue 2 (2024): In Progress

In order to enable the unlimited use of thermal energy from fluids in natural environment, the need for a completely new power cycle arose that would be the most efficient and could generate power from low temperature sources (e.g. seas, lakes or atmosphere). The idea to apply an injector (ejector or thermal compressor) in a power cycle led to the discovery of the Injection Power Cycle (IPC). As the efficiency of conventional Thermal Compressor (TC) was not sufficient to allow the operation of the IPC in real conditions, a cooling stream was introduced into the conventional TC. In this way the compression of Working Fluid (WF) is intensified resulting in an increase of overall efficiency of TC. However, the efficiency of the IPC was still slightly below the efficiency of the Rankine Power Cycle (RPC). In order to further increase the efficiency of IPC, the external turbine is shifted into the TC allowing the use of full heat potential of the total mass flow of WF through the TC. That is how the IPC became the most efficient power cycle. Finally, the author proposes to use power from marine solar-thermal power generation system based on the IPC to drive a seawater desalination-electrolysis plant in order to produce potable water and/or Hydrogen.

In tribology studies, the interaction between solid and liquid surfaces is a common focus, with particular attention given to wear rates and surface scars. These wear and scar issues are analyzed through adsorption mechanisms. A key factor in these problems is the orientation of the liquid on solid surfaces, which requires an in-depth examination of molecular orientations. This study aims to investigate the adsorption mechanisms of liquids on solid surfaces by analyzing structural quantities such as density and orientation order parameters. The research employs molecular dynamics simulations to model a gold solid with face-centered cubic (FCC) (100) surfaces in contact with three different alkanes (pentane, heptane, and 3-ethylpentane). The simulations are conducted at a uniform temperature set at 0.7 of the liquid's critical temperature. Results indicate that liquids with linear molecular structures exhibit higher adsorption behavior compared to those with branched structures, which affects heat transfer near the contact interfaces. Further research is needed to explore how the surface structure of the solid affects these interactions.

Methanation, which synthesizes methane from carbon dioxide and hydrogen, can potentially be an important core technology for realizing a carbon-neutral society. A catalyst is normally used in the methanation process, but its thermal degradation is a serious problem. Thus, we have proposed a catalyst-free methanation reactor that simulates an internal combustion engine. We call it a Methanation Reciprocating Engine (MeRE), where the up-and-down motion of the piston inside the engine creates a high-temperature, high-pressure field inside the reactor that is suitable for the methanation reaction. In this study, we conducted a 0-dimensional simulation using a program package, Chemkin-II. To make clear the reactor characteristics based on the reaction process in the MeRE, we used an ICEN code (Internal Combustion Engine) to simulate the MeRE. We changed the initial temperature, the components of reactants, the rotational speed, and the compression ratio. It is found that the reaction rate of methane production can be enlarged by increasing the initial temperature, the compression ratio, and the rotational speed. Additionally, it is better to set the composition which is close to the stoichiometric ratio of the Sabatier reaction. For all cases, the CO₂ conversion rate is high, but the CH₄ selectivity is very low. Resultantly, in the case of the MeRE, it is easy to produce CO from CO₂, while the reaction which converts from CO to CH₄ is unlikely to take place.

This study investigates how men and women in MINT countries contribute to enhancing energy efficiency across various sectors through technological innovation. Gender plays a pivotal role in the energy efficiency landscape, and this study examines how promoting gender equality and increasing women's participation in innovation can enhance energy efficiency outcomes. Using data from the World Bank and an annual panel dataset of MINT nations from 1997 to 2020, this study analyzes the relationship between energy efficiency and variables such as per capita consumption of renewable energy, GDP, gender, and urbanization. The study uses the panel autoregressive distributed lag (ARDL) model to examine the variables' long- and short-term relationships. The panel ARDL method has two steps: first, testing for the presence of a long-term relationship between the components, and then, using those results, calculating the long-term coefficients. The study used a causality evaluation which considers the potential causal association between the regressors and the dependent series to determine the presence and direction of causal relationships between the two data sets. If a cointegrating link can be established, it suggests that there may be a causal connection between the indicators, while the direction of causation remains unknown. This research provides empirical evidence of the complex interplay between gender, technological innovation, and energy efficiency in MINT countries. It highlights that gender-sensitive policies and renewable energy sources are crucial to the success of international efforts to promote sustainable development.

The service life of equipment is generally linked to degradation factors depending on its operating conditions, including the rate of use and the frequency of the switching modes. The novel operating mode management proposed in this paper takes into account equipment lifetime in addition to all the previously mentioned requirements. This algorithm does not rely only on real-time data, as is traditionally presented in the literature, but also integrates predictive operating data. Therefore, it can be considered as a hybrid operating mode management as it embeds both predictive and event data, which yields improved results with respect to traditional event-driven management. This allows to optimize a criterion over a finite horizon, and, hence, an optimal sequence of the switching times of the different components of an energy system are generated. While the proposed approach is considered to be generic, it is illustrated by the production of green hydrogen from renewable sources. In order to ensure the operating safety and energy efficiency of the system, the objective is to maximize the life duration of the electrolyzer and the batteries by avoiding excessive stored quantities. Simulations using data obtained from a laboratory platform which replicates the process at a smaller scale highlight the effectiveness of the proposed approach.

As smart home technology advances, the quest for sustainable energy management solutions grows. This study examines the interaction between solar energy systems and smart home activities, focusing on using an ESP32 microcontroller to regulate lighting and temperature. The proposed system combines sophisticated software algorithms with authentic hardware components to allow for real-time monitoring and control of light and temperature conditions, as well as online tracking of solar system data. Communication protocols and the ESP32 microcontroller create an integrated smart home system that allows homeowners to control their environment remotely using smart mobile devices. Solar panel installation enhances energy efficiency and decreases dependence on traditional grid-based electricity, promoting an environmentally friendly household setting. This study demonstrates how smart home systems may significantly change household energy usage patterns by evaluating hardware design and software execution to ensure comfort, safety, and sustainability. This research showed considerable advancements in energy conservation and improved home environmental control. We integrated smart controllers and light sensors to reduce daily lighting energy consumption from 0.17 kWh to 0.12 kWh, and our smart system reduced the initial air conditioning energy needs from 15.6 kWh/day to 14.48 kWh/day. These results indicate improvements in energy management and home environmental control.

The influence of gas-pulsed flow when supplied in the perpendicular direction to the refined standard (RS) sugar layer has been studied in this article. Some hydrodynamic parameters of the RS sugar in the gas-pulsed fluidized bed have also been determined. The research results have been applied in the design of the RS sugar dryer using the modern pulsed fluidized bed drying method. The bed porosity in the static particle layer (e₀) was 0.44 while the bed porosity in the minimum fluidized bed (e_mg) was 0.484 and the minimum fluidized bed velocity (U_mg) was 0.65 m/s. The bed porosity in the homogeneous fluidization bed (e_hg) was 0.67, and the homogeneous fluidization velocity (U_hg) of 1.63 m/s has been calculated. The critical velocity (U_cg) of 2.7 m/s and the bed porosity (e_cg) of 0.8 in the circulating particle bed were determined. The pressure drop through the layer of RS sugar with a thickness of 300 mm was 3808 N/m².

Globally, over 3 billion people i.e. almost 40% of world population still depends on biomass fuels such as fuel wood, charcoal, Agricultural residue, dung and coal for household energy use. The biomass energy has a share of more than 30 percent of the energy consumed in Africa. However, in most Sub-Saharan African countries accounted for 90-98 percent of household energy consumption. More than 95 percent of households in Ethiopia depend on biomass as energy source. To understand the importance of efficient wood stove technologies in mitigating the greenhouse gas emission due to burning of woodfuel for household energy use, different published scientific papers were reviewed. The findings shown that combustion of solid fuels for cooking using in efficient wood stoves emits greenhouse gases which have substantial addition to climate change, even though; dissemination and sustained use of improved cook stoves have a potential in mitigating the greenhouse gas emissions due to burning of biomass fuels for household energy use. Furthermore, it reduces the amount of fuelwood consumption which also leads to reduce deforestation and forest degradation. Therefore, achieving dissemination and sustained use of efficient wood stoves at household level have a significant benefit in mitigating the greenhouse gas emission due to burning of fuelwood for household energy use.

This review paper aims to gather informative data on the impact of climate extremes on the physical environment, public health, and the livelihoods of people in Ethiopia. The primary sources of data for this review were peer-reviewed journal articles obtained from electronic databases such as PubMed, Central, Scopus, and Web of Science. Globally, the vast majority of households in developing countries depend on wood energy for their daily energy needs. Such consumption trends are expected to remain a common feature of traditional wood energy production and consumption, at least in the short- to medium-terms. This situation increases the demand for firewood and charcoal from the forest. The process of harvesting standing trees for charcoal and fire wood leads to forest degradation. Although woody biomass has the function of energy consumption, and as a source of income for rural villagers and urban poor dwellers practicing agriculture, wood energy generally has low priority in national policies of developing countries. However, unsustainable management and negative environmental consequences in humid and dry forests is derived from the use of fuel wood energy. Still now there is an unsystematic assessment of the economic contribution and environmental consequences of wood energy use, so its significance and consequences have been minimized. This deforestation and forest degradation contributes 1–2.4 Gt CO₂e of greenhouse gases, which is 2–7% of global anthropogenic emissions, with global greenhouse gas emissions mostly CO₂.