Short Payback Period Research Articles

Thermodynamic and economic analysis of a novel design combining waste tire pyrolysis with silicon production waste heat recovery and organic Rankine cycle

In this study, a novel design highly integrated with waste tire pyrolysis, silicon production waste heat recovery, and organic Rankine cycle has been developed. In the hybrid configuration, waste tires are converted into useful pyrolysis oil and carbon through pyrolysis. At the same time, the waste heat generated by silicon production is recovered to generate additional electricity, and provides electricity and heat for tire pyrolysis, allowing the subsystems to be closely coupled and achieving self-sustain the energy consumption of the entire system. And a thermodynamic and techno-economic of the hybrid system is investigated based on the simulation results. The thermodynamic results show that the energy efficiency and exergy efficiency of the proposal can achieve 64.14% and 72.13%. The techno-economic results indicate that the proposal has a short dynamic payback period of 3.79 years and a high net present value of 26,231.40 k$. The results confirmed that the novel design is advantageous from the perspectives of both thermodynamics and economics.

Renewable energy scenarios for water desalination and conveyance: Case of red sea-dead sea project

The objective of the Jordan Red Sea-Dead Sea (RSDS) project is to transport desalinated water from the Gulf of Aqaba to the Dead Sea. It aims to resolve two fundamental issues in Jordan: the lack of potable water in the country's center and the low water level in the Dead Sea. Desalinated seawater should be pumped from the Gulf of Aqaba to the Dead Sea as part of the RSDS project.This study is not only the first study to focus on the feasibility of using renewable energy sources to meet the project's energy needs, but the approach taken in this research is also novel. It employs a variety of software packages in order to accomplish the research goals. Thus, a number of operational scenarios for the RSDS project employing renewable energy technologies, as these resources are essential for sustainable development, are proposed. Based on the availability of renewable energy sources in the project region, only solar and wind technologies are included in the technology selection process. The selection of a suitable technology from renewable energy technologies was based on eight scenarios that were developed using several selection criteria. The social, technical, environmental, risk evaluation, and financial impact scenarios were investigated. Analytic hierarchy process and multi-criteria decision analysis were utilized to evaluate the electricity generation options for the project. The results indicated that the economic scenario is the optimal scenario for covering the entire load. Levelized Cost Of Energy (LCOE) and payback period are sub-criteria for this scenario. The primary goal of this scenario is to cover the load with the lowest LCOE and shortest payback period possible. The results indicated that a 945 MW Photovoltaic plant and a 630 MW wind energy plant are required to cover the total loads for desalination and water pumping. Energy storage is essential in any scenario where renewable energy sources are used to meet demand. Electric vehicles are employed in this research as a kind of energy storage to lessen the demand for more traditional storage methods. The number of 85 kWh electric vehicles needed to replace traditional storage medium is estimated. It is determined that 53,614 and 57,584 electric vehicles in the 24 hour and 12 hour operating times, respectively, are required under the economic scenario.

GENETIC POTENTIAL FOR MILK AND CHARACTERISTICS OF LACTATION ACTIVITY OF COWS OBTAINED BY PUREBRED BREEDING AND CROSSING

GENETIC POTENTIAL FOR MILK AND CHARACTERISTICS OF LACTATION ACTIVITY OF COWS OBTAINED BY PUREBRED BREEDING AND CROSSING

Synergies between China's Whole County photovoltaic program and rural heat pump adoption

AbstractElectrification of heating, particularly with highly‐efficient heat pumps, is increasingly viewed as essential for reaching the targets of the Paris Climate Agreement. China has promoted replacement of dirty coal heating in rural areas. More recently China has also begun promoting distributed solar photovoltaic (PV) energy as a rural development strategy, particularly with the launch of the Whole County PV pilot program in 2021. While several studies have examined the economics of heat pump adoption, with or without solar PV, the Whole County PV program has not been specifically studied. Further, many prior studies utilize monthly average solar production or temperature ranges. This study examines the economics of heat pumps in participating counties in the Whole County PV program, employing hourly data for both PV output and ambient temperature in participating counties. The analysis shows that pairing residential heat pumps with PV in counties in Shandong, Henan, and Jiangsu would result in short economic payback periods versus gas or resistance heat, while also increasing self‐consumption of PV. The results suggest that expanding the Whole County PV program to incorporate energy efficiency and heating/cooling measures represents an economically attractive way to accelerate the rural energy transition and improve rural livelihoods. Such a policy would help accelerate the low‐carbon energy transition, reduce air pollutant emissions, and help address oversupply of midday PV output in local areas. Barriers to the approach include involvement of different government ministries, the cost of upgrading building insulation, the design of building codes, and the structure of electricity tariffs.This article is categorized under: Sustainable Energy > Solar Energy Energy and Power Systems > Electrification Cities and Transportation > Buildings

Scientization or parametrization? Which system is more advantageous to environmental conservation in the reform of China's state-owned forest farms?

Government leadership and grassroots participation are the most typical institutional arrangements in natural resource management, a topic which has been the subject of vigorous debate for a long time. Individually, these systems are referred to as scientization and parametrization. This paper takes the reform of China's state-owned forest farms (SSFs) as a pointcut, comparing the effects of the 2011 policy (representing scientization) and the 2015 policy (representing parametrization) on environmental conservation. For the period from 2006 to 2018, China's provinces are analyzed via difference-in-differences (DID) and principal components difference-in-differences (PCDID) empirical strategies. The results show that the 2015 policy increased new afforestation by an average of 0.903 units, but the 2011 policy had no significant impact. The influence path of the 2015 policy was to curb corruption, relieve fiscal stress, and stimulate innovation, playing mechanism effects of 20.49%, 14.17%, and 33.55%, respectively. However, the 2015 policy was not ideal in terms of its goal of incentivizing multi-agent participation in investments in conservation. Investors prefer to attempt afforestation projects with shorter payback periods, especially projects related to open forest land. Overall, this study supports the belief that parametric management is a better approach to natural resource management than scientific management, but the latter approach still has limitations. Therefore, we propose to prioritize the promotion of parametric management on the closed forest lands of SSFs, but there is no need to hastily mobilize grassroots participation in open forest land management projects.

Optimal insulation of underground spherical tanks for seasonal thermal energy storage applications

The literature deals specifically with compressed gas characteristics, solar radiation, storage volume and heat load fluctuation in aboveground storage and thermal energy storage (TES) applications. To prevent their negative effects, the use of underground insulated spherical tanks in the storage process has been overlooked. This study details the physical and economic aspects of using insulation in underground spherical tanks for seasonal TES systems. In determining the storage heat load, the degree-time method is recommended for the heat transfer mechanism between soil and storage temperature degrees. Using life cycle cost analysis, the insulation thickness, energy saving and payback period in the underground spherical tank are discussed in detail for hot and cold storage capacities. The results of the study indicated that the degree-hour method can be used in the design of hot and cold TES systems despite the temperature fluctuation. Insulation can be taken care of in hot fluid storage instead of cold alternative. With insulation in the underground spherical tank, it is observed than about 200 % energy savings is possible with approximately 50 % shorter payback period. For the hot fluid storage with insulation, as the storage fluid temperature, soil thermal conductivity and tank diameter rise and the depth falls, but the optimum insulation thickness value increases. As a result, this study is expected to be a guide for further seasonal TES applications using insulation in underground spherical tanks.

Thermo-economic performance limit analysis of combined heat and power systems for optimal working fluid selections

In previous works, we have proposed the thermodynamic performance limit analysis methodology for the organic Rankine cycle for analyzing the impact of working fluid properties on system performance. Here the concept is extended to the thermo-economic performance limits, and is applied to a combined heat and power system based on an organic Rankine cycle. Working fluids are characterized with 8 characteristic thermodynamic and transport properties based on a corresponding state model and a residual entropy scaling approach. The 8 fluid characteristic properties along with 3 system operational parameters are optimized using a multi-objective genetic algorithm; a Monte Carlo algorithm is further adopted to avoid sub-optimal convergences. As the result, the performance limits could be well represented by the trade-off (Pareto front) between the maximized thermal efficiency and minimized payback period. The impact of the fluid characteristic properties on both thermodynamic and economic targets is investigated and ultimately guided the choice of working fluids: low molar mass, low thermal conductivity scaling factor, high viscosity scaling factor and high critical pressure are always preferred. "Wet" working fluid is preferred for a high thermal efficiency while "dry" working fluid is favored for a short payback period. Critical temperature has the most profound impact, while ideal gas isobaric heat capacity and acentric factor have negligible impacts. The choice of working fluid, system design (e.g., recuperative effectiveness) and system operational parameters (e.g., evaporation temperature) highly depends on the given hot sources and the preferences to the thermodynamic and economic targets.

Теоретико-методологический фундамент цифровой трансформации сельского хозяйства России: базовые понятия и этапы

Abstract. The purpose of the study is to try to form a theoretical and methodological basis (foundation) for the digital transformation of agriculture in Russia. In this study, the initial part of the work on the formulation of the conceptual framework of digital transformation is carried out. The article is theoretical in nature. The methodological basis of the study was the process and system approaches. The scientific novelty lies in the theoretical and methodological justification of the digital transformation of agriculture in Russia. Results. It is revealed that the abrupt and spontaneous nature of the policy of digital transformation of the industry carried out in Russia, due to the introduction of certain digital technologies (mainly with the shortest payback period), is a key problem of the low level of digitalization of agricultural production in the country. To solve this problem, a comprehensive and systematic approach is proposed, implying coverage of all stages of digital transformation: from specification (setting goals and objectives of digital transformation) to decision-making based on digital data and changes in business processes within a single digital ecosystem. Based on this approach, a theoretical and methodological foundation for digital transformation in agriculture should be developed, on which all regulatory, strategic and forecast documents developed in the field of digital transformation will be based. It is shown that the theoretical and methodological foundation includes such elements as basic concepts, stages, principles, indicators and evaluation methodology. The last element is extremely important for the gradual development of digital transformation, since it should be used to assess the level of implementation of each stage. Complete completion of the previous stage will allow you to move on to the next one.

A New Mode of a Natural Convection Solar Greenhouse Dryer for Domestic Usage: Performance Assessment for Grape Drying

It is known that the natural convection (NC) solar drying process is a simple and cheap method for drying foodstuffs, but it is not preferable for common users in the case of drying high-moisture content agro-products due to the slow rate of drying. Meanwhile, the forced convection (FC) drying process is most appropriate for such products, but its economic feasibility may be affected due to high initial and maintenance costs. Therefore, the present study proposed a controlled natural convection (CNC) drying mode using a solar greenhouse dryer (SGD) for drying grapes with two types of cover materials, glass and Plexiglas, through intermittent operation with a PV system to save energy as a simple and inexpensive domestic dryer instead of the common forced convection SGD and the conventional natural convection SGD. The obtained results of the new CNC drying mode using a Plexiglas SGD showed a higher drying rate than the NC drying mode and are close to the FC drying mode using the same cover material. The initial moisture content of the grapes was reduced from 5.91 g water/g dry matter to the final moisture content of 0.15 g water/g dry matter within 12 h and 15 h for the CNC and NC drying modes, respectively, using the Plexiglas SGD. Moreover, the thermal drying efficiency for the two mentioned drying modes was 12.5 and 9.7%, respectively. The Page model was found to be the most appropriate model to predict the kinetics of the SGD in all drying modes, regardless of the cover type. The new CNC drying mode using the Plexiglas SGD achieved the lowest cost per kg of dried grapes (1.26 USD/kg), the highest total saved costs over the lifespan of the dryer (USD 245.46) and the shortest payback period (1.08 years) compared to the other two dryers, NC-SGD and FC-SGD. Generally, the CNC-SGD had good performance over the NC-SGD because it is not affected by the fluctuation in the volume, velocity and direction of the inlet ambient air/wind during drying grapes as a high-moisture content product without external heating sources or complicated parts. Thus, the proposed drying system has the advantage in terms of simplicity, cheapness and saving energy compared to FC-SGD.

Sustainable insulation solutions for hydroponic greenhouses: The effects of textile waste reinforcement on thermal microclimate

Recycling waste into construction materials represents an adequate solution to both the problem of energy shortage and environmental pollution problem. This study investigated the impact of incorporating textile waste in cementitious blocks to improve the microclimate of greenhouses. The study involved a year-long experimental investigation of a transparent greenhouse (Ref_Gh) and a thermally insulated hydroponic greenhouse (THP_Gh), followed by the development of a numerical model to assess the thermal environment of a hydroponic greenhouse (TRC_Gh) built with cement blocks made by replacing 30% of the sand volume with textile fibers. The results showed that the daytime temperature variation inside the TRC_Gh was 2 °C higher than in the THP_Gh, but still much lower than that in the Ref_Gh. However, the reference greenhouse showed the lowest temperature values at night. The TRC_Gh showed a significant heat demand at night, higher than the demand for the THP_Gh but still lower than the demand for transparent shelter, peaking at 90 W/m2 in December. The study concluded that a hydroponic greenhouse built with textile-reinforced cement blocks offers better thermal performance than a greenhouse made with Plexiglas, but thermal-panel greenhouses still offer the best thermal performance. However, an economic analysis showed that a TRC_Gh has a 1.3-year shorter payback period than a THP_Gh. Overall, this study highlights the benefits of recycling textiles into construction insulation materials. The novelty of this work lies in its approach to improving the microclimate of hydroponic greenhouses by integrating a new insulation material in an efficient and environmentally friendly way.

Exergoeconomic and Exergetic Sustainability Analysis of a Combined Dual-Pressure Organic Rankine Cycle and Vapor Compression Refrigeration Cycle

In this paper, an exergoeconomic and exergetic sustainability analysis of a dual-pressure organic Rankine cycle (ORC) and vapor compression refrigeration cycle (VCRC) driven by waste heat is performed for power generation and cooling production. In addition, the most suitable fluid couple among the thirty-five different fluid pairs was investigated for the proposed combined system. The results indicate that the highest energy utilization factor, exergy efficiency, the system coefficient of performance, and net power are calculated for the R123-R141b fluid pair. In terms of exergetic sustainability indicators, the best performance results are obtained for the R123-R141b fluid combination. The minimum unit electricity generation cost and the shortest payback period are calculated as 0.0664 $/kWh and 2.5 years, respectively, for the R123-R290 fluid pair. The system component with the highest exergy destruction is the boiler, with 21.67%. The result of the parametric analysis showed that the thermodynamic performance parameters increase with the increment of the ORC’s boiling temperature. In addition, with the increasing boiling temperature, the environmental effect factor of the system decreases, while the exergetic sustainability index increases. Additionally, as the boiling temperature increases, the total system cost increases, while the unit electricity production cost and payback period decrease. It is suggested to use a R123-R141b fluid couple among fluid pairs created as a result of thermodynamic, exergoeconomic and sustainability analysis.

Water Management of Organic-Based Pineapple in Upland Sloping Production Areas

Irrigation of crops in the upland is one major problem in crop production because of water availability during the dry season which includes the right irrigation water method, one of major factors in crop production. The main objectives of the study were to assess the growth and yield of organically grown pineapple at different water management; and to evaluate the cost and economic returns of organically grown pineapple at different water management. Study conducted at BPSU Bangkal, Abucay, Bataan (N 14°46’ East 120°30’). The total rainfall depth at BPSU-AWS Station for July 2020 to June 2022 was 5,002.4 mm during the study period. The micro-sprinkler irrigation system (90 lph, 5.5 m – 12.5 m WD) was used to supplement the irrigation water. Four treatments were subjected for verification (T1 – no supplemented water, T2 – Irrigate up to 30% soil MC, T3 - Irrigate up to 50% soil MC, and T4 – Irrigate up to 70% soil MC) with the aid of an Atmometer and Soil Moisture Meter. Pineapple (T4) has 72.7 cm high, 109.5 cm crown diameter with 25.7 leaves, and T4 has the most number of large size (126/179). Pineapple production has a good return in terms of income, and ROI, and has a short payback period compared with other commodities. With the application of supplemented irrigation water to upland and rolling production areas, the farmer’s income could increase with the right irrigation method for specific and selected crops to be raised.

Optimization of Heat Pump Systems in Buildings by Minimizing Costs and CO2 Emissions

District heating systems are gaining global recognition as an essential tool for reducing greenhouse gas emissions and transitioning to a low-carbon-energy future. In this context, heat pumps are becoming an important technology, providing an effective solution for improving energy efficiency and reducing the reliance on fossil fuels in heating systems. Therefore, this study is focused on the optimal selection of heat pump systems for different types of buildings considering technical, economic, environmental, and social factors. This paper proposes a novel methodology based on mixed-integer nonlinear programming and multi-objective optimization that minimizes total costs and reduces CO2 emissions for heat production and supply systems over a desired period. The methodology is applied to various building types, including renovated and unrenovated apartment buildings, schools, kindergartens, and a supermarket. The study analyzes various types of heat pumps and electric heaters for space heating and domestic hot water production. Optimization results showed that the optimal heating system includes air-to-water heat pumps and electric heaters. Furthermore, for schools and a supermarket, these systems are combined with hybrid heat pumps. The goal of making the heating system neutral in terms of CO2 emissions was achieved for eight out of eleven buildings analyzed. The most profitable investments were in the heating systems of renovated five-story and unrenovated nine-story apartment buildings due to their low energy costs (0.0831 EUR/kWh), short payback periods, and high returns on investment.

Design and Performance Evaluation of Integrating the Waste Heat Recovery System (WHRS) for a Silicon Arc Furnace with Plasma Gasification for Medical Waste.

A hybrid scheme integrating the current waste heat recovery system (WHRS) for a silicon arc furnace with plasma gasification for medical waste is proposed. Combustible syngas converted from medical waste is used to drive the gas turbine for power generation, and waste heat is recovered from the raw syngas and exhaust gas from the gas turbine for auxiliary heating of steam and feed water in the WHRS. Meanwhile, the plasma gasifier can also achieve a harmless disposal of the hazardous fine silica particles generated in polysilicon production. The performance of the proposed design is investigated by energy, exergy, and economic analysis. The results indicate that after the integration, medical waste gave rise to 4.17 MW net power at an efficiency of up to 33.99%. Meanwhile, 4320 t of the silica powder can be disposed conveniently by the plasma gasifier every year, as well as 23,040 t of medical waste. The proposed design of upgrading the current WHRS to the hybrid system requires an initial investment of 18,843.65 K$ and has a short dynamic payback period of 3.94 years. Therefore, the hybrid scheme is feasible and promising for commercial application.

Net-zero energy optimization of solar greenhouses in severe cold climate using passive insulation and photovoltaic

To take into account the crop growth of greenhouse and reduce energy consumption, this study investigated to optimize and retrofit a typical solar greenhouse in the severe cold climate of China into a net-zero energy solar greenhouse (NZESG). The envelope passive insulation measure and roof flexible photovoltaic (PV) technique are innovatively combined and some optimization cases were proposed based on simulation and analytical studies. The foamed cement insulation boards with different thicknesses and envelope positions were added as 11 passive insulation retrofit cases. The flexible PV panels in checkerboard (PV1), horizontal (PV2) and longitudinal (PV3) arrangements were positioned on the greenhouse roof and their electrical energy was estimated through PVsyst software. The optimal case was obtained based on the local technical standard for nearly zero energy consumption buildings and energy-saving, carbon reduction, payback period and cost multi-objective entropy weight method. The key finding is that passive energy-saving retrofit Case (a) & PV1 has the highest comprehensive score and is the optimal NZESG case. Its investment cost and payback period of Case (a) & PV1 are 45526.40 CNY and 5.23 years respectively. Case (a) adopts 50 mm foamed cement board with external insulation. Although the effect of energy-saving and CO2 reduction is poor, Case (a) has the shortest payback period and the lowest cost. PV1 has the lowest investment and higher power generation. It also shows that the investment payback period and cost weight are high, which are the key parameters for comprehensive evaluation of the retrofit cases; The entropy weight method is objective and scientific. The retrofit measures and optimization method can facilitate the promotion and application of NZESGs.

Thermo-physical and energy performance of building envelope modified by natural fiber through building information modelling

The insulating capacity of building envelope materials is vital in defining the heating and cooling (H & C) energy demand. A sustainable strategy for conventional envelope materials is hybridization with natural or waste fibers for better thermal performance. Therefore, this study was designed to use natural (bamboo, coconut coir, jute, sisal) and waste (polyester) fibers for modified envelope materials (brick and mortar). Firstly, the influence of fibers on thermo-physical properties of thermal conductivity, bulk density, porosity, water absorption was analyzed for the brick and mortar made of the aforementioned five fibers. As a result, the best fiber type for the insulating performance is determined as coconut and jute for brick and mortar, respectively. Next, the energy performance of an envelope with best fiber modified material was investigated through BIM energy analysis in terms of H & C loads. Simulations were performed for five cases by modifying the three-layer wall assembly and further by varying the brick layer thickness (115 − 230 mm), while the mortar thickness was set as 20 mm. Lastly, economic feasibility was assessed by quantifying the payback period for each thickness. Experimental results revealed that the thermal conductivity of the fiber modified brick and mortar was reduced by 18 and 10%, respectively, by virtue of decreased bulk densities and increased porosity and water absorption. It was also found that the thermo-physical properties have a high interdependency by correlation matrix analysis. For the peak H & C loads analysis, they were reduced for fiber modified materials by maximum of 15% and 9%, respectively, as compared with the unmodified envelop material. Furthermore, by increasing thickness from 115 to 230 mm the H & C loads were reduced up to 43% and 33%. Consequently, the addition of the natural or waste fibers was economically feasible with short payback periods (12–48 months) even though the volume fraction of fiber was just 1%.

Rationale for Parameters of Energy-Saving Illumination inside Agricultural Premises and Method of Its Values Calculation

High-quality lighting of premises in the cultivation of farm animals is an important condition for the successful development of the agro-industrial complex. Sufficient lighting with the simulation of sunrise and sunset which increases daylight hours to 15–16 h can raise the level of production by 8–15%. The most innovative, economical and efficient light source for livestock, poultry and greenhouse buildings are LED lamps allowing for a short payback period. The difference between the models developed by the authors and the traditional point method is taking into account lamp length o, lamp suspension height, location of the illuminated area under the lamp at displacement and observation angles, and luminous flux of light source, and the most important thing is body angle of the light source. This paper presents the method for calculating illumination under the LED lamp due to the large error in the values obtained by theoretical methods due to the lack of a correction factor for changing the illumination of the lamp (0.8). Prediction of crystal heating was carried out by verification calculation in the ANSYS/CFX software package. Forecasting the illumination of the fodder table was carried out by calculation in the DIALux evo software package. The main parameters of an energy-saving LED lamp (power consumption, luminous flux, color temperature and color) were selected. The consumption of electrical energy decreased by 85%; the average level of illumination increased and amounted to 123.1 lux. The developed method for calculating the illumination under the LED lamp can be considered satisfactory, the Student and Fisher criteria do not exceed tabular values and the correlation coefficient showed a close relationship. To comply with electrical safety standards in the premises, a resonant power supply system for LED lamps is offered.

Wind energy potential assessment for co-generation of electricity and hydrogen in the far North region of Cameroon

The fast increase of Cameroon population growth rate and the actual shortage of electricity plaguing the country, particularly in remote areas, give rise to great challenges in the energy generation sector. Nowadays, renewable and clean energy sources are used to foster and improve electricity production via hydrogen generation with water electrolysis. This paper therefore scrutinizes the wind energy potential alongside the electricity and hydrogen generation from wind energy for the cities of Kousseri, Kaele, Maroua, Mokolo, Mora and Yagoua in the Far North Region of Cameroon using wind speed data recorded at 10 m, 40 m and 70 m heights for the years 2011–2021. Several performance indicators including the wind power density, wind turbines power output, wind turbines capacity factor, hydrogen production, cost of produced electricity and hydrogen and payback period are utilized to evaluate the techno-economic viability of the system. This assessment was carried out employing twenty-two commercially accessible wind turbines. Our findings revealed that, Kousseri displays the best hydrogen output with yearly hydrogen production ranging from 3.5054 to 53.232 tons of hydrogen. The annual compressed hydrogen to be saved in this region was found to be in the range of 92.5049 to 1404.70 m3. Enercon E-48/800 turbine records the highest capacity factor in all the chosen locations with the lowest cost of energy varying from 0.0578 $/kWh at Kousseri to 0.0838 $/kWh at Mora. The lowest cost of hydrogen was found to be 4.3865 $/kg for Kousseri, 5.5284 $/kg for Kaele, 5.7160 $/kg for Maroua, 5.9439 $/kg for Mokolo, 6.5065 $/kg for Mora and 6.3354 $/kg for Yagoua employing GE 1.5SL turbine. The highest annual energy output of 3193.9, 2738.1, 2488.4, 2393.9, 2153.3 and 2323.1 MWh was acquired at Kousseri, Kaele, Maroua, Mokolo, Mora and Yagoua, respectively. The shortest payback period was found to be 2.9 years which was related to the case where Enercon E-48/800 wind turbine was assumed to be installed at Kousseri. Finally, the maximum CO2 emission minimization to be achieved if electricity produced by wind turbine is utilized in place of oil burning power plant and power plant that burns natural gas as fuel was 885.36 tons of CO2 and 641.60 tons of CO2, respectively.

Numerical modeling of wind turbine with vertical axis using turbulence model k − ω in ANSYS FLUENT

The paper considers a variant of the problem of modeling the flow around a developed wind turbine. Since the task is reduced to modeling a flat task, the 2D design mode was chosen. The k – ω turbulent model was used to model the vertical axis wind turbine. In the research process, experimental methods for measuring wind speed and torque, methods of mathematical modeling, and computational fluid dynamics were used. The object of research is a wind turbine designed to generate electricity from wind energy. The research aims to develop a wind turbine with a vertical axis and radial frames, equipped with flat blades and stoppers, operating at low wind speeds. Research methods: in the research process, experimental methods for measuring wind speed and torque, methods of mathematical modeling, and computational hydrodynamics were used. A computational experiment HTBO with four sections based on the ANSYS environment was carried out. Scope of the results: the results will be used in designing and manufacturing wind turbines operating at low wind speeds. Ultimately, low-power wind turbines will be developed. Economic efficiency and significance of the work: the wind turbine being developed is made with available purchased materials and will have a short payback period. It is used for domestic and other purposes where access to electricity is limited.

A Preliminary Review of Poly(lactic acid)-based Biodegradable Foam and its Techno-economic Model

Biodegradable polymers using renewable resources with properties that are comparable to bio-based and fossil-based polymer materials at a comparable cost have been studied and developed in an effort to solve environmental issues, especially expanded polystyrene. One potential raw main material to replace EPS is poly(lactic acid), a synthetic polymer made from lactic acid, which is made by fermenting organic materials like sweetcorn, rice, soya, potatoes, or whey. It is used in food and non-food packaging, drug-controlled release, agriculture, automotive, and electronic accessories. Foaming is vital in developing lighter, more cost-effective materials that may be utilized for a range of purposes due to their general features, such as lightweight, good heat, more ductile (elastic), and excellent energy absorption (impact resistance). In this review, different types of foaming processes and their process parameters are focused at. It was written following the procedures outlined in the PRISMA2020 (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines for conducting a review to reports and evaluating a wide variety of interventions. Furthermore, a sustainable material should focus on the efficacy of its resource consumption and the economic feasibility of the product it creates. An economic feasibility study is also provided in this article aims to evaluate how much profit a production plant can make. The techno-economic model developed in this study yielded a profit on sales of 69.69% and an internal rate of return of 44.0%. Techno-economic modeling favored the commercial use of poly(lactic acid)-based biodegradable foam based on its positive net present value, short payback period, and high internal rate of return.