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Cryogenic liquid expanders have emerged as a potential energy‐saving alternative to Joule–Thomson (JT) valves in cryogenic processes. The potential impact of incorporating a liquid expander into the Rectisol process has not been quantitatively evaluated. This study seeks to assess the effectiveness of replacing the JT valve with a liquid expander in the Rectisol process through the development of thermodynamic models for each component and conducting simulations using the ASPEN software. Additional analyses, including energy, CO2 footprint, exergy, and economic evaluations, are performed for the Rectisol system. Utilizing an expander has been shown to lower energy usage by 2.52% and boost CO2 capture by 5.55%, resulting in a 7.65% decrease in energy expenditure per unit CO2 and a 1.29% rise in total exergy efficiency. Lower expander outlet temperatures and the green power output generated by the expander are the main reasons for these benefits, and the CO2 footprint analysis explains how they work. The application of an expander in the Rectisol process is an economical and low‐risk solution; the payback period is 0.32 years, and the lifetime profit is 53 folds of the investment. [ABSTRACT FROM AUTHOR]

Energy storage (ES) units are vital for the reliable and economical operation of the power system with a high penetration of renewable distributed generators (DGs). Due to ES's high investment costs and long payback period, energy management with shared ESs becomes a suitable choice for the demand side. This work investigates the sharing mechanism of ES units for low-voltage (LV) energy prosumer (EP) communities, in which energy interactions of multiple styles among the EPs are enabled, and the aggregated ES dispatch center (AESDC) is established as a special energy service provider to facilitate the scheduling and marketing mechanism. A shared ES operation framework considering multiple EP communities is established, in which both the energy scheduling and cost allocation methods are studied. Then a shared ES model and energy marketing scheme for multiple communities based on the leader–follower game is proposed. The Karush–Kuhn–Tucker (KKT) condition is used to transform the double-layer model into a single-layer model, and then the large M method and PSO-HS algorithm are used to solve it, which improves convergence features in both speed and performance. On this basis, a cost allocation strategy based on the Owen value method is proposed to resolve the issues of benefit distribution fairness and user privacy under current situations. A case study simulation is carried out, and the results show that, with the ES scheduling strategy shared by multiple renewable communities in the leader–follower game, the energy cost is reduced significantly, and all communities acquire benefits from shared ES operators and aggregated ES dispatch centers, which verifies the advantageous and economical features of the proposed framework and strategy. With the cost allocation strategy based on the Owen value method, the distribution results are rational and equitable both for the groups and individuals among the multiple EP communities. Comparing it with other algorithms, the presented PSO-HS algorithm demonstrates better features in computing speed and convergence. Therefore, the proposed mechanism can be implemented in multiple scenarios on the demand side. [ABSTRACT FROM AUTHOR]

While phytoremediation has been widely employed for greywater treatment, this system suffers from the transfer of considerable amounts of surfactants to the aquatic environment through partially treated effluent and/or exhausted plant disposal. Hence, this study focuses on greywater phytoremediation followed by recycling the spent plant for preparing an adsorbent material used as post-treatment. P. crassipes was used to operate a phytoremediation unit under 23 °C, 60% relative humidity, plant density (5–30 g/L), dilution (0–50%), pH (4–10), and retention time (3–15 days). The optimum condition was 12.7 g/L density, 34.0% dilution, pH 8.4, and 13 days, giving chemical oxygen demand (COD), surfactant, and NH4-N removal efficiencies of 94.62%, 90.45%, and 88.09%, respectively. The exhausted plant was then thermally treated at 550 °C and 40 min to obtain biochar used as adsorbent to treat the phytoremediation effluent. The optimum adsorption process was biochar dosage of 1.51 g/L, pH of 2.1, and 137 min, providing a surfactant removal efficiency of 92.56%. The final discharge of this phytoremediation/adsorption combined process contained 8.30 mg/L COD, 0.23 mg/L surfactant, and 0.94 mg/L NH4+-N. Interestingly, this approach could be economically feasible with a payback period of 6.5 years, 14 USD net present value, and 8.6% internal rate of return. NOVELTY STATEMENT: The research succeeded in treating greywater by phytoremediation followed by recycling the exhausted P. crassipes plant to prepare an adsorbent material used in the post-treatment phase, giving an economically feasible scenario with 6.5-year payback period. [ABSTRACT FROM AUTHOR]

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Saudi Arabia faces significant challenges in managing the rising energy consumption in buildings driven largely by its hot climatic conditions. As a result, retrofitting building facades to enhance energy efficiency has become a critical strategy. This study assesses the effectiveness of various façade retrofit strategies in reducing cooling electricity consumption using a real-time case study in Dhahran, Saudi Arabia. The strategies explored include external wall upgrades, window replacements, and installation of shading devices. Each strategy was evaluated individually, considering the reduction in heat gains, cooling load, and payback period as key performance indicators. To further maximize energy efficiency, these strategies were also analyzed in combination using the genetic algorithm optimization method, yielding 224 possible facade configurations. The optimal solution included the use of an External Thermal Insulation Composite System (ETCIS) in walls, louvers in windows, and low-emissivity coating with Argon gas-filled glazing, achieving a cooling energy reduction of approximately 16% and a payback period of 14.8 years. This study provides several recommendations for improving the efficiency of retrofitting building façades in hot climatic conditions. [ABSTRACT FROM AUTHOR]

To meet the escalating electricity demand and rising fuel costs, along with notable losses in power transmission, exploring alternative solutions is imperative. Gas turbines demonstrate high efficiency under ideal International Organization for Standardization (ISO) conditions but face challenges during summer when ambient temperatures reach 40°C. To enhance performance, the proposal suggests cooling inlet air by 15°C using a vapor absorption chiller (VAC), utilizing residual exhaust gases from a combined cycle power plant (CCPP) to maximize power output. Additionally, diverting a portion of exhaust gases to drive an organic Rankine cycle (ORC) for supplementary power generation offers added efficiency. This integrated approach not only boosts power output but also minimizes environmental impact by repurposing exhaust gases for additional operations. This study presents a detailed energy and economic analysis of a modified combine cycle power plant, in Kotri, Pakistan. R600A is used as organic fuel for the ORC while LiBr-H2O solution is used for the VAC. Two performance parameters, efficiency and energy utilization factor, Four energetic parameters, Work output of ORC, modified CCPP, original CCPP and cooling rate, and one economics parameter, payback period were examined under varying ambient conditions and mass fraction of exhaust gases from outlet of a gas turbine (ψ). A parametric investigation was conducted within the temperature range of 18°C to 50°C, relative humidity between 70% and 90%, and the ψ ranging from 0 to 0.3. The findings reveal that under elevated ambient conditions (40°C, 90% humidity) with ψ at 0, the Energy Utilization Factor (EUF) exceeds 60%. However, the ORC exhibits a low work output of 100 KW alongside a high cooling load of 29,000 kW. Conversely, the modified system demonstrates an augmented work output of approximately 81,850 KW compared to the original system's 78,500 KW. Furthermore, the integration of this system proves advantageous across all metrics. Additionally, the payback period of the system is contingent on ambient conditions, with lower conditions correlating to shorter payback periods and vice versa. [ABSTRACT FROM AUTHOR]

This research seeks to combine a comprehensive analysis of the literature regarding energy efficiency and inverters with an analysis of a configuration of a hybrid energy system including a generator, an inverter and a battery. The inverter's power output is analyzed under the influence of different distribution functions during a robust modulation procedure for achieving optimum energy saving. The modulation is tested on two processing machines independently: (a) an electric discharge machine, and (b) an injection molding machine. Based on the research methodology, problem formulations and the conducted analysis, a novel research software called "Inverter Pro V1" was programmed to analyze the estimations and performance of inverters in an energy system. An optimal levelized cost of electricity was determined given certain systems design and operating hours, and a sensitivity analysis was undertaken that identified a range of energy savings. In the sensitivity and optimization analysis, interactions among the primary decision parameters including the system's capacity, operating time, energy saving, cost of energy and payback period are investigated. It is also found that for each system, the inverter modulation categories with the optimum payback period belong to a modulation of inverter designed according to the Sawtooth function with a 45% duty cycle and switching intervals of 0.35 s. By considering the operating hours of 12.5 h per day, and the calculated system's investment cost of €31,782.158, the optimum payback period is estimated to be 1.7729 year. The study results are to inform policy with regard to assisting sustainable electricity production. [ABSTRACT FROM AUTHOR]

Solar panel installation is generally exposed to dust. Therefore, soiling on the surface of the solar panels significantly reduces the effectiveness of solar panels. Accumulation of dust also shortens their lifespan and reduces efficiency by about 15% to 20%. A significant reduction in the efficiency of solar photovoltaic panels has been observed due to inadequate insulation and dust deposition or shading. To harness maximum solar energy from solar panels up to their rated capacity, they need to be cleaned periodically. Therefore, the current study focuses on the comparative performance analysis of two distinct types of self-cleaning mechanisms, namely self-cleaning wiper (SCW) and nano-coating method. These methods are economical and sustainable for the standard atmospheric conditions of Pakistan. Solar panels (reference, nano-coated, and self-cleaning wiper mechanism) were placed on the roof of the Mechanical Engineering Department MUST Mirpur AJK for five weeks. Solar irradiance, dust density & performance parameters of these three panels were recorded on weekly basis. It was observed that an increase in the rate of dust deposition negatively affects the conversion efficiency of solar panels. When dust density was increased from 7.5 to 18.15 (g/m2), the percentile drops in rated power (50W) for reference, nano-coated, and self-cleaning wiper mechanisms are 37%, 33% and 23%, respectively. Moreover, the payback period of nano-coated and SCW is 1.07 years and 2.79 years, respectively. [ABSTRACT FROM AUTHOR]

Adopting additive manufacturing in investment casting, known as rapid investment casting, can significantly reduce lead time and cost. Despite many publications on these technologies, no quantitative techno-economic analyses refer to rapid investment casting. The paper provides helpful insights and a decision-making approach for replacing conventional production technologies (i.e. wax injection) with additive manufacturing technologies. The study is based on a techno-economic analysis framework. It allows assessing key performance indicators (e.g. crossover points and payback periods) for stakeholders to decide the suitable VAT photopolymerisation processes (i.e. stereolithography, digital light processing, and material jetting) according to specific production scenarios (i.e. load factors). Analytical cost models were developed in the frame of this work to assess the time and cost of the overall manufacturing process of the resin model for investment casting, considering the post-processing stages for each of the technologies investigated. The cost models were used to assess the benefits introduced by additive manufacturing in rapid investment casting. A sensitivity analysis evaluated the impact of energy, material, and labour costs for both key performance indicators (crossover points and payback periods). The techno-economic analysis yielded the following results: (i) crossover points in terms of production costs vary, ranging from thousands of units for small components in the jewellery or fashion industries to a few dozen units for larger parts in the mechanical industry, and (ii) crossover points in terms of time are lower than those related to cost. Additionally, digital light processing is regarded as the most promising technology, offering the best crossover points and payback periods across various scenarios, mainly when 3D printers are used at a low utilisation rate. [ABSTRACT FROM AUTHOR]

We examine feedstock cost and minimum selling price for ethanol production from corn stover as a function of scale, stover yield, participation rate, and price incentives for two conversion technologies: a conventional base case featuring thermochemical pretreatment with added cellulase, and an advanced case featuring consolidated bioprocessing with cotreatment (C‐CBP). Delivered feedstock cost ranged from $85 Mg−1 at small (10 million gallons year−1 or ~38 million L year−1) scale with high yield and participation rates to $124 Mg−1 at large scale (60 million gallons year−1 or 227 million L year−1) and low yield and participation rates. The minimum ethanol selling price (MESP) was approximately twofold lower for the advanced case compared with the base case. The payback period was several times lower for the advanced case compared with the base case, with increasing disparity at smaller scales, and was highly sensitive to ethanol price supports. For both C‐CBP and the conventional processing paradigm, MESP decreased with increasing scale, indicating that the cost penalty due to higher feedstock transport distances was more than outweighed by lower capital costs. However, the cost penalty for operation at small scale, expressed in $ gallon−1 ethanol, is lower for C‐CBP than for the conventional paradigm by roughly twofold. Particularly for initial applications of C‐CBP, we speculate that this cost penalty will likely be modest compared with the anticipated benefits of small‐scale operation such as increased opportunity to use existing infrastructure, easier plant siting and supply chain establishment, and lower total investment required. [ABSTRACT FROM AUTHOR]

The green fodder deficit is the biggest bottleneck for livestock productivity in semi-arid regions, especially for resource-poor farmers. Low-cost climate-smart hydroponic chamber (CSHC) based hydroponic fodder production provides a viable solution under such an environment. A CSHC equipped with a fan pad-based evaporative cooling system, controlled drip watering system and smart air exhaust system was designed and developed at ICAR-IGFRI, Jhansi, India with the aim of modifying the inside growth environment of the chamber for improved production of quality fodder. The developed CSHC was capable of maintaining daily average temperature and relative humidity in the range of 23-280C and 87-90%, respectively, with an average cooling efficiency of 78.3%. This efficient cooling was an outcome of specialized CSHC designed with an effective covering material (UV stabilized 200 µm LDPE), shade net with 70% shading efficiency, fan pad-based evaporative cooling system, controlled drip watering system, and smart air exhaust system; which enabled ambient environment conducive for optimum plant growth. Among the different treatment combinations of seed loading rates and soaking hours, the highest maize biomass yield of 2.58 kg/ft2 was achieved after seven days with a seed loading rate of 300 g/ft2 when the seed was soaked for 12 h. At the highest productivity of biomass, the values of dry matter, crude protein, and crude fiber contents were found as 13.51%, 13.71%, and 15.12% respectively. The benefit-cost ratio of the developed CSHC was 1.32 with a payback period of 3.12 years. The developed CSHC was found productive and profitable; hence, it can create a great impact in achieving feed security under resource deficit conditions of climate-change-affected semi-arid regions across the globe. [ABSTRACT FROM AUTHOR]

Aiming at the problem of excessive energy consumption in the thermal regeneration system of a rectisol process in a certain petrochemical engineering company, process improvement is carried out. A closed heat pump distillation model was proposed, using NRTL thermodynamic model with annual total cost and thermodynamic efficiency as objective functions. Process parameters were optimized and their economic and environmental benefits were analyzed under different compression ratios. The research results show that closed heat pump distillation can effectively reduce the use of superheated steam and condensate when the compression ratio is 1.8, and the total energy consumption is reduced by 62.71% . When the investment payback period are 5 years and 8 years, annual total cost is reduced by 15.64% and 32.79%, respectively. The thermodynamic efficiency has been improved from the original 8.78% to 20.96%, which has excellent economic and environ-mental benefits, and the results of the study are expected to provide guidance for the development and design of advanced heat pump distillation technology. [ABSTRACT FROM AUTHOR]

This study aims to provide an overview of sweet bread production as an alternative in planning and developing teaching factories based on business feasibility projection analysis. A quantitative technique was applied in this research. Survey techniques and statistical tests were used to examine the hypotheses. To demonstrate that an institution can and should continue its sweet bread business, several variables were measured, including the Internal Rate of Return (IRR), Net Present Value (NPV), Return on Investment (ROI), Benefit--Cost Ratio (B/C ratio), Payback Period (PBP), and Break Event Point (BEP), providing further information for Business Model Canvas analysis of a business model. Based on the BMC, the value propositions are a variety of sweet bread, ease of access, affordable prices, quality, and taste. Key activities include sweetbread production, stock management, marketing and promotion, and customer service. Customer segmentation involves students, lecturers, staff, and institutional visitors. An analysis of financial projections reveals that business is feasible. This can be seen from IRR = 53,19%; the NPV > 0 is equal to IDR 85,222,327; ROI = 216.69%; B/C ratio =1.07; BCR >1; PBP = 41 months; and BEP = IDR 5,528,669.25. [ABSTRACT FROM AUTHOR]

Geothermal energy is utilized due to its sustainability and ability to provide a continuous low-emission source of heat, making it an ideal complement to the high-efficiency requirements of modern power plants. This study investigates a novel configuration coupling a solid oxide fuel cell-gas turbine unit with a dual-flash binary geothermal structure, enhanced by low-temperature electricity generation and hydrogen production subsystems. This configuration incorporates a regenerative steam Rankine cycle and a proton exchange membrane electrolyzer to achieve an efficient overall design. The setup is evaluated from thermodynamic and economic perspectives using a non-dominated sorting genetic algorithm-II for optimization. A complete parametric study assesses the sensitivity of critical variables. Multi-objective optimization is conducted across three scenarios considering exergy efficiency, hydrogen production rate, sum unit cost of products, and the payback period as objective functions. Results indicate an optimal exergy efficiency of 56.95% and a hydrogen production rate of 0.22 kg/h, with a product unit cost of $7.06/GJ and a payback period of 1.12 years. The parametric study underscores the significant impact of the number of solid oxide fuel cells and their existing density on key variables of the presented configuration. This study highlights the system's potential for efficient and economically feasible power and hydrogen production. • Investigating a novel geothermal-solid oxide fuel cell-gas turbine configuration. • Combining Rankine cycle and proton exchange membrane electrolyzer for higher efficiency. • Enhancing the thermodynamic and economic performances through multi heat recovery. • Achieving 56.95% exergy efficiency and 0.22 kg/h hydrogen production rate. • Achieving unit cost of $7.06/GJ and payback period of 1.12 years. [ABSTRACT FROM AUTHOR]

An optimization study on thermal insulation applied to building exteriors has been performed in this research. Solar radiation has been considered while obtaining optimum insulation thicknesses for various directions. Analyses have been conducted not only for the cardinal directions (south, north, west, and east) but also for the intermediate directions (southeast, northeast, northwest, and southwest). Solar radiation received by vertical walls and cooling and heating degree day values have been computed according to directions. This research examines the most suitable insulation thicknesses for different seasonal usage scenarios, considering cooling, heating, and annual energy demands. Variations in energy cost savings, savings rates, payback periods, seasonal energy demands, and optimum insulation thicknesses for various wall orientations have been presented. Additionally, correlations providing the total cost based on the applied insulation thickness for each direction and various building usage scenarios have been determined. The results indicate that incoming solar radiation varies from 52.08 W/m2 to 111.82 W/m2 across different wall orientations, while energy cost savings range from 23.48 USD/m2 to 24.56 USD/m2, with savings rates between 69.8% and 70.3%. Payback periods range from 5.94 to 6.05 years. Depending on the wall orientation, optimum insulation thicknesses vary between 4.52 and 5.02 cm for heating, 1.56 and 2.09 cm for cooling, and 5.92 and 6.08 cm for annual energy requirements. The heating energy demands ranged from 54.8 MJ/m2 to 58.38 MJ/m2, while the cooling energy demands varied between 10.91 MJ/m2 and 12.08 MJ/m2, depending on the wall orientation. It has been concluded that the ideal insulation thicknesses for meeting cooling, heating, and annual energy demands vary depending on the wall orientation and the building's use purpose. [ABSTRACT FROM AUTHOR]

A study was conducted in North Rahong District, Manggarai Regency. This research aims to analyze the income and financial feasibility of pig farming businesses in North Rahong District, Manggarai Regency. The sampling method is carried out in two stages. In the first stage, sample villages were determined from 12 villages, 4 sample villages were purposively determined by considering having the largest number of pigs. The second stage of determining sample breeders was carried out non-proportionately at random, where 15 respondents were taken from each village to obtain 60 respondents. Primary data was obtained through direct observation and interviews with breeders based on a list of questions that had been prepared, while secondary data was obtained through documented reports from relevant agencies and literature. The data analysis method is income analysis and financial analysis using the criteria for net investment B/C, BEP unit, BEP rupiah, and Payback Period. The research results show that the average total income is IDR 9,079,804.89/year, namely 37.61% is cash income and 62.99% is non-cash income. The results of the financial feasibility analysis show that the pig farming business in North Rahong District is financially feasible with a B/C value of 0.85, unit BEP of 0.33 ST, Rupiah BEP of IDR 3,200,999.78 and PP value of 1 year (12 month). [ABSTRACT FROM AUTHOR]

Recovering ethane from natural gas involves significant energy consumption. Globally, the recycle split vapor process (RSV) is widely adopted as an efficient method for ethane recovery. Nonetheless, one major challenge faced by the RSV process is the lack of adequate heat integration, despite its overall effectiveness. In this article, we investigate the heat integration of the RSV process and propose two novel ethane recovery processes: the recycle split vapor process with direct heat integration of the feed gas (RSV‐DTI) and the recycle split vapor process with split heat integration of the feed gas (RSV‐SHI). A comparative analysis is conducted among these three processes, focusing on integrated energy consumption, exergy efficiency, and economic investment. The study's findings reveal the following: (1) The RSV‐DTI process distinguishes itself with its reduced energy consumption, enhanced stability, and minimized refrigerant usage. In comparison to the RSV process, the RSV‐DTI process achieves a reduction of over 15% in total compression duty and a remarkable decrease of 68% in propane usage. (2) Electricity emerges as the predominant energy consumed in the ethane recovery process, and the RSV‐DTI process significantly improves upon this aspect. Notably, the RSV‐DTI process incurs the lowest investment cost, yielding a swift payback period of approximately 1 year for the plant. The characteristics of the RSV‐DTI process are investigated, and the effect of changes in feed gas conditions on the heat integration of the RSV‐DTI process is analyzed. The characteristics of the RSV‐DTI process show the following: (1) Different pressures of feed gas existing in the main cold box have different minimum heat integration temperatures (MHIT). When the feed gas temperature is lower than the MHIT, heat integration becomes difficult, and the heat energy can be supplied by hot liquid propane at 48°C. When the feed gas temperature is higher than the MHIT, changes in feed gas temperature have little effect on the process, only affecting the external gas temperature. (2) The heat transfer duty of the demethanizer sideline outlet stream is affected by the feed gas pressure. To enhance heat integration, it is recommended to set the heat transfer duty of the low‐temperature sideline outlet stream (DLTSS) between 40% and 90% of the reboiler duty and the heat transfer duty of the high‐temperature sideline outlet stream (DHTSS) between 40% and 75% of the reboiler duty. [ABSTRACT FROM AUTHOR]

In order to fully apply liquefied natural gas (LNG) cold energy to the refrigeration system, four different types of CO2 multiphase refrigeration systems using LNG cold energy are designed. In this paper, (1) CO2 single-stage compressed solid and gas phase refrigeration cycle (SSCC1), (2) CO2 single-stage compressed solid and solid phase refrigeration cycle (SSCC2), (3) CO2 double-stage compressed solid and gas phase refrigeration cycle (DSCC1), and (4) CO2 double-stage compressed solid and solid phase refrigeration cycle (DSCC2) are combined with CO2 liquid phase secondary refrigerant cycle (RC), respectively, to effectively use LNG cold energy. The performance analysis, exergy analysis, economic analysis, and CO2 emission analysis of the proposed systems are carried out by establishing the mathematical models. The results show that the intermediate pressure of DSCC1-RC and DSCC2-RC reaches the best performance at 0.3 MPa, and the system performance decreases with the increase in intermediate temperature. The refrigerating capacity of the CO2 liquid phase secondary refrigerant cycle, the COP, and the exergy efficiency of four kinds of CO2 multiphase refrigeration systems decrease with the increase in the refrigerating capacity of the CO2 refrigeration cycle, while the power consumption of SSCC2-RC and DSCC2-RC decreases, SSCC1-RC and DSCC1-RC increased. The system with the shortest exergy loss is DSCC2-RC at 654.01 kW, while the system with the shortest payback period is SSCC2-RC at 0.88 years, and DSCC2-RC has the smallest CO2 emission. Four CO2 multiphase refrigeration systems and the ammonia combined refrigeration system with the same total refrigerating capacity are compared and analyzed, respectively; the results show that the performance, economy, and CO2 emission of CO2 multiphase refrigeration system are better than those of ammonia combined refrigeration system; and the exergy loss of CO2 multiphase refrigeration system is generally larger than that of ammonia combined refrigeration system because of the large temperature difference in heat transfer. [ABSTRACT FROM AUTHOR]

This study investigates the usage of photovoltaic (PV) and thermal collectors separately to assist a heat pump for supplying domestic hot water (DHW). Usage of PV and thermal collectors together to assist a heat pump and experimentally validated simulation of an air source heat pump can be considered as novelty of this study. Firstly, experimental tests were performed in a climatic room to validate the developed simulation model. Four experimental parameters, namely the coefficient of performance of the air source heat pump, average tank temperature, and heat pump inlet and outlet temperatures have been used for the validation and the highest obtained deviation was 4.5%. Simulations were carried out by adding thermal collectors and photovoltaic panels in different combinations, with a maximum of three collectors to assist the heat pump that provides DHW. For scenarios with one and two solar components (PV or thermal), applying only thermal collectors was more efficient and economical for both with a payback of 3.9 years and 4.3 years, respectively. For the scenario with three solar components, although the system supported by one thermal and two photovoltaic collectors was the most efficient option, the system supported by three photovoltaic collectors was the most economical scenario with a payback period of 4.6 years. The study found that combining thermal and photovoltaic collectors can significantly reduce energy consumption for DHW. [ABSTRACT FROM AUTHOR]

• A compression-assisted absorption refrigeration cycle using R32/DMAC is developed. • Enable the implementation of solar absorption refrigeration in refrigerated warehouses. • Using 60∼80 °C solar hot water obtains a low evaporation temperature of −20∼0 °C. • There is an 18.2 % reduction in electricity consumption compared to traditional method. Solar absorption refrigeration technology is considered an ideal alternative to energy-intensive refrigerated warehouses due to its decarbonization and environmental friendliness. However, it faces challenges in competing with vapor compression refrigeration, such as high driving heat source temperature (>100 °C) and a long payback period. In this paper, we address these challenges by focusing on cycle structure and working pair, and propose a compression-assisted absorption refrigeration cycle (CARC) using R32/dimethylacetamide (DMAC) as working pair. The aim is to significantly reduce driving heat source temperature by adjusting absorption pressure utilizing an auxiliary compressor, enabling the cycle to be connected to low-cost and efficient non-concentrating solar collectors, thereby effectively shortening its payback period. This cycle includes two operating modes: CARC mode powered by solar energy during the daytime and vapor compression refrigeration cycle mode driven by off-peak electricity at night, ensuring 24-hour cooling capacity for refrigerated warehouses. The results indicate that this cycle can flexibly utilize 60∼80 °C solar hot water easily obtained as driving heat source and its evaporation temperature decreases to -20 °C. To assess its performance benefits, a compression-assisted absorption refrigeration system is developed and implemented. By utilizing the limited roof area of a refrigerated warehouse, it can achieve an 18.2 % reduction in electricity consumption and a 24.2 % reduction in carbon emissions compared to the vapor compression one annually. Additionally, during peak electricity demand periods in summer, the system exhibits significant energy-saving effects, and its payback period is about 4.2 years. Ultimately, this cycle provides a viable solution for energy-saving and emission reduction in refrigerated warehouses. [ABSTRACT FROM AUTHOR]

Climate-smart agriculture (CSA) is a climate-resilient practice that stands out globally as an important practice through which we can deal with emerging challenges through adaptation and mitigation to increase crop productivity and resilience. Despite its significance, a comprehensive cost–benefit analysis of the adoption of these practices has not yet been carried out. This study aims to bridge the knowledge gap between the cost and effectiveness of CSA practices adopted by small-scale farmers in growing rice, wheat and maize, the most staple crops in the Gandaki River Basin of Nepal. In this study, net present value (NPV), internal rate of return (IRR), benefit–cost (BC) ratio, net benefit investment (NK) ratio and payback period, along with the value of externalities (social and environmental), were employed to assess the profitability of CSA practices. The findings indicate that almost all the CSA practices analyzed were profitable, with the exception of solar water management in maize with very low IRR (6%) and a longer payback period. The outcome of this study offers valuable insights for farmers in choosing profitable CSA technology and for policy makers in promoting better CSA technology, upscaling CSA practices, and formulating new agricultural policies and programs in the context of the changing climate. [ABSTRACT FROM AUTHOR]

Challenges and opportunities are faced in the development of marginal oil reserves that are often uneconomical to exploit conventionally. The main objective of this study was to determine whether the project is a viable investment based on the given assumptions, as well as whether the potential returns can justify the risks associated with marginal oil reserves. The research method involved the use of key financial metrics such as Net Present Value, Internal Rate of Return, and Payback Period, using a discount rate of 10%, which is standard in the oil and gas industry. The results show that the project has a positive NPV of USD 124,462.38, an IRR of 13.13%, and a PBP of 4 years and 5 months. These results indicate that the project is financially viable, with returns exceeding the capital cost of the project. Further sensitivity analysis identified that oil prices and production levels are the most critical factors affecting the financial outcome of the project. Compared to the WACC of 10.25%, the IRR of 13.13% indicates that the project exceeds the minimum required rate of return, thus justifying the investment. The implications of this study highlight the importance of proper operational management and market risk mitigation to maintain profitability. [ABSTRACT FROM AUTHOR]

The investment estimation of the helium extraction project from natural gas is a crucial step in economically obtaining helium from both domestic and international projects. This article employs Aspen HYSYS to simulate the process and estimate the investment levels of Linde and Exxon Mobil integrated helium extraction processes. We investigate the influence of feed composition and processing capacity on investment costs and product returns. The results indicate that higher helium content of feed correlates with increased equipment investment costs and total capital cost (CAPEX), and that the Linde integrated process is significantly more sensitive to changes in helium content of feed than the Exxon Mobil integrated process. As the helium content of feed rises, the product returns of the two processes are evidently improved, leading to reduced investment payback periods. Both techniques exhibit favorable payback periods when the feed helium content exceeds 0.5 vol%. Nevertheless, elevated nitrogen content in the feed notably escalates the equipment investment costs and total capital costs. Furthermore, an increase in the processing capacity of feed gas leads to a nonlinear increase in total capital costs and annual operating costs. However, the cost per unit of helium extraction diminishes with increasing capacity. In general, the Linde integrated process requires higher separation energy consumption in comparison with the Exxon Mobil integrated process at similar processing capacities. Moreover, the sensitivity analysis shows that helium breakeven price is strongly affected by the price of both LNG and feed gas. [ABSTRACT FROM AUTHOR]

This paper compares concentrated and distributed reactive power compensation to improve the power factor at the point of common connection (PCC) of an industrial electrical system (IES) with harmonics. The electrical system under study has a low power factor, voltage variation, and harmonics caused by motors operating at low loads and powered by variable-speed drives. The designed compensation system mitigates harmonics and reduces electrical losses with the shortest payback period. Four solutions were compared, considering concentrated and distributed compensation with capacitor banks and harmonic filters. Although the cost of investment in concentrated compensation is lower than that of distributed compensation, a higher reduction in electrical losses and a lower payback period are obtained with distributed compensation. Although the lowest payback period was obtained with distributed compensation with capacitor banks (0.4 years), it is not recommended in the presence of harmonics because the effects of current harmonics significantly reduce the useful life of these elements. For this reason, distributed compensation with harmonic filters obtained a payback period of 0.6 years, and it was proposed as the best solution. These results should be considered in projects aimed at power factor compensation in IESs with harmonics. The concentrated compensation of the capacitor bank at the PCC is proposed because of the lower investment cost and ease of installation. However, the advantages of distributed compensation with harmonic filters have not been evaluated. An energy efficiency approach is used to analyze the impact of the location methods of the power factor compensation equipment on the electrical losses of the IES. [ABSTRACT FROM AUTHOR]

Limited material options and economic conditions significantly restrict the potential for energy efficiency improvements in rural houses in China's cold regions. It is worth exploring how to propose suitable energy-saving renovation plans for rural houses in cold regions under practical constraints. By using Grasshopper within Rhinoceros 8 software, an algorithm integrates material selection, energy consumption calculations, and economic analysis. The method efficiently generates thermal optimization schemes, providing insights into energy use, costs, and payback periods. In a case study of a typical rural house in Daqing City, the optimized scheme achieved over 70% energy savings compared to traditional homes, with renovation costs amounting to less than 40% of residents' annual income and a 2-year payback period. This significant improvement highlights the potential of the proposed method in enhancing the energy efficiency and economic viability of rural house renovations. [ABSTRACT FROM AUTHOR]

This paper deals with the investigation of N identical compound parabolic concentrator evacuated tubular collector included single slope solar desalting unit (N‐CPC‐ETC‐SSU) by incorporating energy metrics for solving contemporary issue of water scarcity in the society. It will contribute to the sustainable development of society and recede the dependency on fossil fuels, too. The energy metrics investigation is important for energy system because it talks about the feasibility of the system. The methodology consists of getting fundamental equations from energy balance equations. All fundamental equations with relevant data are fed to the code developed in MATLAB followed by the computation of overall energy and exergy. All types of climatic situations have been considered for the analysis. Data required for the same are accessed from IMD, Pune, India. The energy payback period, energy production factor, and life cycle conversion efficiency for N‐CPC‐ETC‐SSU have been calculated at eight number of collectors, 0.012 mass flow rate and 0.14 m water depth. Results of N‐CPC‐ETC‐SSU have been compared with results of SSU included with ETCs. Concludingly, energy payback period is lower by 6.41%, energy production factor is higher by 6.25% and exergy‐based life cycle conversion efficiency is higher by 96.39% for N‐CPC‐ETC‐SSU than N‐ETC‐SSU. [ABSTRACT FROM AUTHOR]

Effective utilization and conservation of freshwater is a global concern due to the rapid population growth and industrial usage. To address this challenge, various approaches have been developed and implemented to convert brackish water into freshwater and meet the global water demand. This study introduces hexagram-shaped aluminum fins attached to a powder-coated basin to improve the freshwater production rate of stepped solar still. The experiment involved testing the modified stepped solar still (MSSS) equipped with hexagram fins and the conventional stepped solar still (CSSS) without hexagram fins during summer days at the Sathyamangalam location (11.49° N, 77.27° E). A mathematical model was used to analyze the performance of the solar stills, and the simulation results were validated by comparing CSSS and MSSS in terms of their freshwater production. The results indicate that the productivity of CSSS increased by 40% using hexagram fins, and the MSSS with hexagram fins produced a maximum of 4.45 l/m2 of fresh water daily. The annual performance of MSSS and CSSS in the experimental location reveals a 12.6% reduction in the payback period of the solar still due to the presence of fins. The study recommends using fins in solar stills in hot climates for efficient and cost-effective water desalination applications to achieve sustainable development objectives while reducing carbon emissions. [ABSTRACT FROM AUTHOR]

The Rongchang–Dazu region in western Chongqing (eastern Sichuan Basin, China), known for its seismic activity, is a promising area for deep geothermal resource development; however, practical development is limited. Key geological understandings, such as heat flux, geothermal gradients, the nature of heat sources, thermal reservoir rock characteristics, and the classification of geothermal resources, remain in need of further study. In this work, the targeted area is surrounded by Sinian–Cambrian carbonate gas fields. An analysis of the deep geothermal prospects was conducted using exploration and development data from the Gaoshiti–Moxi gas fields within the Longwangmiao and Dengying Formations. The results indicate that the Rongchang–Dazu area has relatively high heat flow values and geothermal gradients within the Sichuan Basin, correlating with fault structure and seismic activity. Gas test data confirm that the Longwangmiao Formation in the study area reaches depths of 4000 to 4500 metres and exhibits anomalous pressures and temperatures exceeding 140 °C. Meanwhile, the Dengying Formation of the Sinian system lies at depths of 5000 to 5500 metres, with normal pressure, minimal water production, and temperatures exceeding 150 °C, characterising it as a dry-hot rock resource. Adjacent to western Chongqing, the Gaoshiti area within the Longwangmiao Formation, with an estimated flow rate of 100 kg/s, shows that the dynamic investment payback period is significantly shorter than the estimated 30-year life of a geothermal power plant, indicating strong economic viability. Deep geothermal resource development aids in conserving gas resources and enhancing the energy mix in western Chongqing. Future research should prioritise understanding the links between basement faults, seismic activity, and heat flow dynamics. [ABSTRACT FROM AUTHOR]

In the present study, the performance of a solar dryer supported by an indirect type wicked heat pipe was assessed. To transfer the heat from the solar collector to the drying chamber, a passive high thermal conductivity heat pipe was developed. At 1:30 pm, there was a 21 °C temperature difference between the drying chamber and the ambient air. The results indicated that after 12 hours of drying, the banana slices' moisture content dropped from 150 % d.b. to 11 % d.b. It is found that the average drying rates in Trays 1, 2, and 3 are the following: 0.1452, 0.1492, and 0.1613 kg water/kg dry matter/h. The effective moisture diffusivity ranged from 1×10−7 to 9.405×10−8 m2/s, whereas open sun drying had the lowest average effective moisture diffusivity of 3.87×10−07 m2/s. The estimated dryer efficiency was 26 %. Also the payback period of developed dryer was found to be 0.57 years. The developed dryer can be installed in any rural villages to dry any agricultural products. [ABSTRACT FROM AUTHOR]

The evolving legislation regarding electricity billing for both consumers and prosumers, coupled with the growing interest in photovoltaic installations with energy storage, provided the motivation to examine the operational and financial viability of a prosumer photovoltaic installation located in Poland. Two options were considered: a standard photovoltaic system without energy storage and an installation with batteries. Furthermore, four scenarios were analyzed, each reflecting a different way of accounting for the electricity bought and sold by the prosumer. Another scenario is that energy prices are influenced by a high share of renewable sources. As the changes to the billing scheme are a recent development, there is no relevant analysis currently available. In order to ensure the reliability of the analysis, PVsyst 7.4 software was employed to establish the main performance and financial parameters for the selected PV systems. Analysis showed that using an energy storage system will increase the energy self-consumption from 28.6% to 60.4%, which in some cases would have a great influence on profitability of the investment. In the worst scenario, the payback period is too long (13.7 years). But in the most favorable scenario, with additional financing, it drops to 3.9 years. [ABSTRACT FROM AUTHOR]

Plastic waste is utilized aggressively for food, product packaging, cosmetics, toys, clothes, and even furniture. As a result, discarded plastic as a waste has grown uncontrollably worldwide, most of it ending up as landfill. With increasing concern, researchers have made efforts to convert this plastic waste into a more useful product. Along these lines, this study focuses on producing 10 tons of diesel per day through fast pyrolysis at 450 °C in the fluidized bed reactor for a feed rate of 3000 kg of plastic waste per hour. The production was simulated in Aspen HYSYS V11 to ensure the desired yield. Further, a detailed economic analysis is carried out to estimate the return on investment and total cost per year, as well as the payback period and the profit for different scenarios. [ABSTRACT FROM AUTHOR]

One of the most important issues in the maritime industry is controlling and reducing the amount of emissions caused by marine vessels. In this respect, the International Maritime Organization sets some air pollution-related regulations and encourages maritime companies to utilise current and innovative emission abatement methods on their ships. The application of these approaches to ships not only provides environmental benefits but also creates additional financial costs for the company. In this study, operational data of a container ship has been acquired and examined. Methods such as ammonia, LNG, scrubber, low sulphur fuel use, and selective catalytic reduction have been considered to determine the most appropriate emission reduction approach. Nine different scenarios have been created with the use of stated methods and each scenario is analysed both environmentally and economically and compared to each other. Finally, the most suitable scenario has been determined by calculating the payback period of each investment. Since there is a relatively longer period of redemption, using a dual-fuel engine could be more suitable for long-lasting and newly built ships. For the currently cruising ships, the use of scrubber systems with selective catalytic reduction is an effective solution to reduce the number of emissions. [ABSTRACT FROM AUTHOR]

In this study, a comprehensive analysis is done on a dual rotor wind turbine (DRWT) in co‐rotating arrangement. First, a co‐rotating dual rotor is designed and its performance is analyzed by blade element momentum theory simulation. Later, the designed co‐rotating DRWT is manufactured and then tested in the field by mounting the wind turbine on a truck. Running the truck steadily at different speeds while logging the performance parameters of the wind turbine, the power curve of the DRWT is obtained. Then, using the power curve of the co‐rotating DRWT and the actual wind measurement data from Çatalca Istanbul, the annual electricity generation of the designed turbine is calculated. The present techno‐economic analysis states that the co‐rotating DRWTs are more efficient compared to single rotor wind turbines (SRWTs), in accordance with the literature. Analyses show that with DRWT, around 22% higher power generation can be achieved. Additionally, the payback period for DRWT was found to be less than 1 year. The marketing strategy for introducing the product emphasizes identifying and targeting early adopters and influencers within the market. The present techno‐economic analysis states that the co‐rotating DRWTs are more efficient compared to SRWTs, in accordance with the literature. [ABSTRACT FROM AUTHOR]

This study investigates the potential of utilizing pyrolysis byproducts, including char and non-condensable gases, as an energy source to promote autothermal pyrolysis. A total of six pyrolysis experiments were conducted at three distinct cracking temperatures, namely, 450 °C, 500 °C, and 550 °C. The experiments utilized two types of biomasses, i.e., 100% pine chips and 75% pine chips mixed with 25% refuse-derived fuels (RDF). The findings from the experiments were subsequently incorporated into a process simulation conducted on Aspen Plus for an energy balance and a techno-economic analysis. The results of the experiments revealed that the energy produced by the byproducts utilizing only pine chips is 1.453 kW/kg, which is enough to fulfill the energy demand of the pyrolysis reactor (1.298 kW/kg). However, when 25% of RDF is added, the energy demand of the reactor decreases to 1.220 kW/kg, and the produced energy increases to 1.750 kW/kg. Furthermore, adding RDF increases bio-oil's lower heating value (LHV). The techno-economic study proposed three scenarios: optimistic, conservative, and tragic. The optimistic has a payback period (PBP) of 7.5 years and a positive net present value (NPV). However, the other two scenarios were unfavorable, resulting in unfeasibility. [ABSTRACT FROM AUTHOR]

A large number of ground-source heat pump (GSHP) systems have been used in residential and commercial buildings throughout the world due to their attractive advantages of high energy and environmental performances. In particular, GSHPs constitute a proven renewable energy technology for space heating and cooling. This paper provides a detailed literature review of the primary aspects of GSHP systems. These include the technological characteristics of HPs and the main types and variations in GSHPs, along with their environmental impact. Other aspects addressed are the integration of GSHPs with other systems, as well as their optimal design and control and energy analysis. The important aspect of the system's performance is also dealt with through case studies and also the barriers hindering the further adoption of GSHPs in buildings. Two important challenges for the adoption of GSHPs is their cost and environmental efficiency. Studies have shown that GSHPs can reach a >>24% lower environmental impact than air-source HPs, while today's technology can allow for a payback period for installing a GSHP of <<5 years. Finally, based on the above review, the future challenges and prospects for the successful uptake of GSHPs is discussed. It seems that through the right steps, the wide adoption of GSHPs as an important form of 'implemented' renewable energy system can become a reality. [ABSTRACT FROM AUTHOR]

Fruits and vegetables are an important part of human diet. In the present study, the thermal performance of a solar greenhouse dryer for drying Solanum lycopersicum (Tomatoes) was analyzed. The drying pattern at various locations of the drying chamber and different levels of the dryer was evaluated. The life cost analysis for drying the tomatoes in the dryer for 25 years of service was evaluated. The greenhouse solar dryer was developed with a structure base of galvanized iron pipes and a covering of a 2 mm thick polycarbonate sheet. The experiment was carried out for drying the tomatoes at various locations in the dryer using the trays and trolley system. The maximum thermal efficiency of the dryer is 26.66 % while drying out 5.8 kgs of tomatoes in one day. The economic analysis of the greenhouse solar dryer shows that the payback period of such a system can be attained in only 1.6 years which terms the dryer feasible and economically viable in the current agro-drying market. The embodied energy for the dryer was calculated at 3154.71 kWh for the system. The CO2 emission for the greenhouse solar dryer was found to be around 6.62 tonnes for a lifespan of 25 years. The net CO2 mitigation was calculated at around 41.62 tonnes which would generate an earning from 46766 INR to 62355 INR worth of carbon credits. [ABSTRACT FROM AUTHOR]

The use of biomass as fuel at PLTU Bolok can reduce emissions, save basic costs for providing electricity and increase fuel alternative competitiveness for PLN. A lot of unproductive vacant land can now be used to plant calliandra trees and used for cofiring, the use of woodchip biomass for cofiring PLTUs can also build a community economy. This research aims to analyze the feasibility of investment using a financial aspect approach in the biomass procurement program in Kupang, NTT. This business feasibility analysis was carried out to find out whether the biomass development plan was feasible from a financial aspect. This research will analyze the Net Present Value (NPV), Net Benefit Cost Ratio (BCR), and Payback Period values for the business. [ABSTRACT FROM AUTHOR]

This article presents the relationship between energy matrices of a dual slope solar desalting unit integrated with a number (N) of photovoltaic thermal flat plate collectors (NPVTFPC‐DSU) and the effect of variation in mass flow rate m˙fr and N for a sustainable solar distillation. Although extensive research has been done on dual slope active solar desalting unit, however, the area of the impact of variation in m˙fr and N on energy matrices of NPVTFPC‐DSU remains still untouched. This study is an attempt to bridge the gap that has been highlighted. An exhaustive analysis is performed considering all types of climatic situations of New Delhi, India. MATLAB is used to calculate the overall energy, exergy, and energy matrices for NPVTFPC‐DSU based on fundamental equations and relevant data as inputs. Concludingly, it is evident that there is a decrease in the value of energy payback period and life cycle conversion efficiency as the value of m˙fr increases at a given value of N for m˙fr ≤ 0.10 kg s−1. For m˙fr>0.10 kg s−1, the values remain constant. For NPVTFPC‐DSU, 6 and 10 are the best and most favorable values of N as far as energy‐based energy matrices and exergy‐based energy matrices are concerned. [ABSTRACT FROM AUTHOR]

Two-thirds of UK higher education institutions operate as energy-intensive buildings and have failed to achieve the 2020 goal of reducing emissions by 43% from 2005 levels, as pledged in 2005. Converting existing buildings into low-emission ones is challenging, and setting achievable targets with sustainable design strategies is crucial. A case study was conducted on the University of Dundee's dental clinic, analysing the economic viability of a hybrid microgrid with an on-site solar photovoltaic, natural-gas-fuelled combined heat and power generator, and the national grid. Three design configurations were analysed: Grid + CHP, Grid + PV, and Grid + PV + CHP. The results showed that the Grid + PV + CHP system has the lowest levelised cost of electricity (LCOE) and is over 75% more cost-effective and shows a minimum of 7.5% reduction in emissions. This configuration has a simple payback period of 2.9 years, a discounted payback period of 2.6 years, a return on investment of 30.1%, and an internal rate of return of 34.4%. [ABSTRACT FROM AUTHOR]

The paper presents the performance evaluation of a modified indirect solar dual collector dryer (MIS2CD) integrated with a thermal storage system for drying myrobalan slices. The design of the solar collector and solar collector with thermal storage was to supply uninterrupted thermal energy to the drying chamber during sunny and sunset hours. To evaluate the dryer performances, one lot (20 kg) of myrobalan was dried in the MIS2CD, and as a result, the thermal efficiency and energy supply period of MIS2CD increased by 12 ± 02% and 41 ± 1.2%, respectively. Drying characteristics of myrobalan slices in MIS2CD, TD, and OSD were studied and compared. A two-term exponential model best explains the drying kinetics of myrobalan slices dried in MIS2CD. The dried sample in MIS2CD results in lesser ΔE* values than TD and OSD methods. The highest exergy efficiency of 78.2% and lower exergy losses were recorded. The energy payback period of the MIS2CD was evaluated as 1.42 years. The CO2 emitted and CO2 reduced reduction are calculated for drying myrobalan in MIS2CD for a lifetime (20 years) of 67.85 kg and 20.65 tons, respectively. The capital cost of the solar dryer design was estimated depending on the economic considerations of the state. The drying hours were increased in MIS2CD against OSD by 59% on the annual sunny days (210 days). The sample drying period MSD and TD to reach the final moisture level of 7% was 9 h and 5 h, respectively. The total economic benefit is 22,622 INR (annually), and the 2.08 benefit–cost ratio for myrobalan dried in MIS2CD compared to TD. The MIS2CD's payback period is nearly 2.18 years, much less than the dryer's lifetime. [ABSTRACT FROM AUTHOR]

Solar drying is a renewable energy-based technique which is widely used for food preservation purpose. In this study, various drying characteristics of the solar-dried Solanum tuberosum samples of different thicknesses have been investigated at variable climate condition of Lucknow. A mathematical model has also been developed to validate experimental results to predict the drying rate, free moisture content, and other parameters. Pre-treatment of the food samples was also done before the experimental runs on the fabricated solar dryer. Global radiation has also been monitored during the study to correlate the heat transfer rate in inner and outer sides of the solar drying chamber. SEM analysis has also been done to analyze the surface morphology of solar-dried samples. All solar dried food samples have uniformly heated. There was no hot-spot condition present on the surface of the samples. The drying efficiency and payback period of the fabricated solar dryer have also been calculated as 22.9% and 1.42 years, respectively. Model data have been found in good agreement with the experimental data within a 5% error. This modified model can be used for different agro-based food materials such as carrot, kiwifruit, and yam. [ABSTRACT FROM AUTHOR]

Solid oxide fuel cell power generation systems are devices that utilize solid electrolytes to transfer ions for electrochemical energy conversion. A wide range of gases can be used as fuel gas, including hydrogen, natural gas, and carbon monoxide. Considering the high cost of pure hydrogen, hydrogen production from natural gas reforming has become a hot research area. In this study, the 4F-LCA method was employed to construct an evaluation framework, with a particular emphasis on the cost analysis of solid oxide fuel cell power generation systems, and uses a bottom-up approach to build a system economic analysis model to visualize the major costs involved in the system. An economic benefit analysis and sensitivity analysis were carried out for the 2 kW natural gas solid oxide fuel cell as a case by taking the financial net present value (NPV), internal rate of return (IRR) and payback period into account. In this study, the investment cost and payback period of a 2 kW solid oxide fuel cell system are obtained, which can provide a reference for the project construction and operation of solid oxide fuel cell systems. [ABSTRACT FROM AUTHOR]

In this paper, experimental work has been presented to study the novel design of a solar crop dryer that includes an inverted absorber perforate type collector with forced airflow. A novel design configuration was constructed and tested in the eastern Algeria climate (El Oued city) for drying potatoes. We aimed to present a test of the thermal performance of the novel dryer and use only clean energy sources for evaluating the drying efficiency. Under real climatic conditions, the experimental test indicated that the average air temperature of the drying chamber is 50 °C, and the time required for drying potatoes starting at the initial moisture content (MC) of 84.17% until the final MC of 12.5% is 6h. The highest specific moisture extraction rate value was obtained as 1.074 g water/kWh. The drying efficiencies ranged from 20.37% to 34.01%, whereas the exergy efficiency ranged from 58.48% to 93.22%. The payback period was estimated as 1.39 years. The proposed novel dryer will dry potatoes free of cost for almost its entire life period, and about $13.92 can be saved. Compared with electric oven drying, the novel one has the following advantages: the cost of electricity saving and avoiding penalty tax for CO2 emission were $11.69 and $2.235, respectively. [ABSTRACT FROM AUTHOR]

In this article, the energy, exergy, and economic analysis of an organic Rankine cycle (ORC) system powered by biogas to provide electricity, heating, and cooling loads for a residential building in Munich city is investigated. Two methods have been proposed to meet the heating and cooling needs of the residential building. In the first method, heating and cooling needs are provided by a heat pump and mechanical refrigeration (System I), and in the second method, these needs are provided by a radiator and absorption refrigeration cycle (System II). In both modes of this system, the effects of battery energy storage (BES) have been analyzed for peak shaving. The working method of this research is that the residential building's electricity, heating, and cooling needs are calculated by Homer and Carrier software, respectively. Engineering equation solver software models the main local power generation system. A new method has been proposed to select the required number of units to meet the needs of the building with and without BES. The results showed that for System I with and without BES, 3 and 1 ORC units with a nominal power of 2 kW can meet all the needs of the building, respectively. In contrast, for System II, the number of 1 unit with 2 kW and 1 unit with 1 kW is needed to meet the energy needs of a residential building with and without BES. It can be concluded that heating and cooling the building with a radiator and absorption chiller cycle is more cost‐effective. The energy and exergy efficiency of ORC is reported as 11.3% and 65.7%, respectively, and the highest exergy destruction rate is related to the heater and boiler. From the economic point of view, the payback period of System II compared with System I is reduced from 18.4 to 5.66 years without using BES. With the use of BES, the payback period is reduced to 5.3 and 5.66 years, respectively. The lowest and highest electricity prices belong to System I with and without BES, which are 3.11 and 0.36 US$/kWh, respectively. [ABSTRACT FROM AUTHOR]

In urban areas facing water stress, rainwater harvesting is essential. This paper proposes a passive rainwater harvesting system as a viable alternative for ensuring a clean water supply. The study introduces an innovative and original design for rainwater harvest. The presentation of the system is performed by analysis of efficiency and reliability of the system analytically. The optimal storage volume is determined through a 22-year precipitation data analysis using the mass balance method, ensuring high efficiency. Payback periods for various consumptions and tank sizes are calculated, showing shorter periods compared to active systems since the proposed system does not use electrical energy. The results demonstrate that 350 m3 of storage volume can assure 99% efficiency when potable water consumption is 0.01 m3/person/day. The payback period of the system was calculated to be between 5 and 10 years. The proposed system can be considered as an appropriate rainwater harvest alternative for existing buildings. [ABSTRACT FROM AUTHOR]

The main target of this research is to allow solar PV to contribute economically to an on-grid energy-efficient building where the dust accumulation is a significant factor. Self-cleaning coatings such as hydrophobic or hydrophilic materials have recently been introduced to reduce dust deposition on building-integrated PV (BIPV) panels. The hydrophilic Nano-coated material is examined as a solution to decrease the impact of the dust on the BIPV panels and harvest more solar energy. An impartial comparison of the BIPV panels performance under natural dust conditions, manual cleaning, and hydrophilic nanomaterial coating is performed. Through an exhaustive and qualitative experimental analysis, the anti-reflection and anti-static properties of the utilized Nano-coated material are examined. The experimental results show that the hydrophilic Nano-coated material significantly improves the gathered maximum output power by 18% compared to the manually wiped panel. The calculated efficiencies of the Nano-coated, manual cleaning, and dusty panels are 11%, 9%, and 6%, respectively, which highlights the futureproofing of the Nano-coated solar panel. Compared to the dusty panels, the ecological and economical results show that the BIPV carbon emissions are desirably dropped by 11% while using Nano-coated PV panels and the payback period is reduced to 3.9 years, which is approximately 12.8% faster. [ABSTRACT FROM AUTHOR]

This paper addresses the optimal sizing of Hybrid Renewable Energy Systems (HRESs), encompassing wind, solar, and battery systems, with the aim of delivering reliable performance at a reasonable cost. The focus is on mitigating unscheduled outages on the national grid in Iraq. The proposed On–off-grid HRES method is implemented using MATLAB and relies on an iterative technique to achieve multi-objectives, balancing reliability and economic constraints. The optimal HRES configuration is determined by evaluating various scenarios related to energy flow management, electricity prices, and land cover effects. Consumer requirements regarding cost and reliability are factored into a 2D optimization process. A battery model is developed to capture the dynamic exchange of energy among different renewable sources, battery storage, and energy demands. A detailed case study across fifteen locations in Iraq, including water, desert, and urban areas, revealed that local wind speed significantly affects the feasibility and efficiency of the HRES. Locations with higher wind speeds, such as the Haditha lake region (payback period: 7.8 years), benefit more than urban areas (Haditha city: payback period: 12.4 years). This study also found that not utilizing the battery, particularly during periods of high electricity prices (e.g., 2015), significantly impacts the HRES performance. In the Haditha water area, for instance, this technique reduced the payback period from 20.1 to 7.8 years by reducing the frequency of charging and discharging cycles and subsequently mitigating the need for battery replacement. [ABSTRACT FROM AUTHOR]

The reuse of energy is a topic currently being widely discussed around the world. This study analyzes the potential for energy reuse in treatment plants. Sewage Treatment Plants are responsible for treating the water present in the sewers of cities. The treated water returns clean to the river, and generally, the place of discharge has a high height and flow rate that can be harnessed for the generation of electric energy. This work investigates the feasibility of installing a Micro Hydroelectric Plant in the Treatment Station of the Uberaba River in Brazil. Hydraulic potential and investment analysis were used as viability criteria. For the study, a height of 6 m and an average flow rate of 0.465 m3/s were considered, which could generate about 22.51 kW using a Bulb water turbine. This power represents a return of US$1651.26 per month from the generation of electric energy. The estimated installation cost was US$32,966.73, and the payback period was found to be less than 2 years. There are 702 sewage treatment plants in Brazil alone, and hypothetical analyses were performed with flow rates ranging from 0.2 to 1 m3/s and heights ranging from 1 to 9 m. Motivating results with payback periods of less than 4 years were obtained for numerous hypothetical situations, which demonstrates the feasibility of installing Micro Hydropower Plants and achieving savings in the sewage treatment system. [ABSTRACT FROM AUTHOR]