Total Energy Output Research Articles

Impacts of groundwater flow on borehole heat exchangers: Lessons learned from Estonia

The production of geothermal energy relies on subsurface properties. In low-enthalpy geothermal regimes, thermal energy extracted with a borehole heat exchanger (BHE) is the subsurface heat conducted from the rock and grout to the BHE fluid. Estonian geology provides a good opportunity to investigate how groundwater flow impacts BHE heat production. The hundreds of metres thick sedimentary rock sequence holds four main aquifers. We modelled single BHEs with lengths of 400 m, 500 m and 1000 m and a BHE field of ten 400-m wells at three sites across Estonia. Then, we parametrized different hydraulic conditions to compare how the groundwater flow velocity impacts the thermal energy yield of the systems.Our results indicate that if groundwater flow increases above 0.03 m/day, it increases the total energy yield from 3 % to 20 %. Thermogeological parameters, such as subsurface temperature and thermal conductivity, affect the thermal energy yield of the wells more than the modelled groundwater flow. Our study provides an estimate of the thermal energy yield from different BHE types and the detailed sensitivity analysis. We conclude that geothermal energy is a significant renewable energy resource for Estonia and areas with similar geology and climate.

Integrated crop management for long-term sustainability of maize-wheat rotation focusing on productivity, energy and carbon footprints

Modern agriculture, driven by diesel-fed machinery, is both energy and carbon-intensive, primarily due to the improper use of inputs. Designing a production module with lower carbon emissions, greater productivity, and enhanced energy use efficiency is crucial for achieving the environmental sustainability. Conservation agriculture based integrated crop management (ICMs) practices have shown promise in improving the productivity, energy-use, and reducing the carbon emissions. In our extensive long-term field study, we explored the crop yields, energy use, and carbon linkages of a maize-wheat rotation under different ICMs practices. Eight ICMs were evaluated over the course of nine consecutive years, which included ICM1&2: conventional (CT) flat-bed maize and wheat, ICM3&4: CT raised bed maize fb wheat without residues, ICM5&6: conservation agriculture (CA)-based double zero tilled (ZT) maize fb ZT wheat with residues and ICM7&8: CA-based triple ZT maize and wheat with residues and green manures. Our results indicated that the system productivity under CA-based ICMs was 16.5–22.9% greater than that under the CT-based ICM1-4. CA based ICM5-8 (125.2–131.5 × 103 MJ ha−1) needed higher energy input than CT-based ICM1-4 (32.7–39 × 103 MJ ha−1), with 76–80% shared by renewable crop residues. Furthermore, the CA-based ICMs recorded significantly higher levels of specific energy, human energy profitability, non-renewable energy use efficiency, and nutrient energy use efficiencies compared to CT-based. Likewise, the CA-based ICMs produced 12.5% more total output energy than the CT-based ICMs. In contrast, the CT based ICMs demonstrated, energy productivity, higher net energy returns and energy profitability. Compared to conventional ICMs, CA-based ICMs produced a 23–36% reduction in spatial carbon emissions and a 31–44 % reduction in yield-scale emissions. Nevertheless, the CA-based practices recorded the higher C- output, C- sustainability and C- efficiency ratio. Greenhouse gas intensity (GHGI) was 33.3–76.2% greater with the ICM1-4 practices than with the ICM5-8 practises. Thus, the present study proposed that adopting the integrated crop management practices based on the conservation agriculture could prove to be productive, as well as carbon and energy-use efficient approach for the maize-wheat rotation. This approach is envisioned to make substantial contributions to both food security and environmental sustainability.

Enhancement of the energy and exergy analysis capabilities of the yoghurt process: a case study of the dairy industry

This study provides a comprehensive analysis of the thermal and exergy characteristics of a dairy plant that produces yoghurt. This study aims to perform a comprehensive analysis of the thermal and exergy aspects of a dairy facility that produces yoghurt. This study also seeks to improve the accuracy of the results by evaluating the reliability of the energy and production data. A comprehensive analysis of energy and exergy is utilized to enhance the yoghurt production process. Moreover, the Grassmann-Sankey diagram is employed to produce a map of energy density. The process’s energy and exergy efficiencies were assessed by taking into account the enhancements and alterations made in addition to the existing implementations. Analysis of the yoghurt production process revealed that the total energy input was 113.9 [kW], the total energy output was 72.05 kW as well and the energy efficiency was 63.3%. The exergy input and output for the yoghurt production process were calculated to be 48.95 [kW] and 29.77 [kW], and the exergy efficiency was determined to be 60.8%. This study is expected to promote the growth of livestock and agriculture in the energy sector, and is forecasted to act as a catalyst for future research. This study, which is the first of its kind in the region and is expected to stimulate further research, reveals that improving energy efficiency and conservation in the production of yoghurt products enhances the factory’s overall energy efficiency.

Analysis of transient energy conversion performance improvement of thermoelectric generator with penetrating crack under pulsed heat source

To simulate the performance of a thermoelectric generator (TEG) in practical applications more accurately and comprehensively analyse the influence of transient heat source and crack on such devices, it is necessary to examine the transient performance of TEGs with cracks under periodic pulsed heat source. In this study, a three-dimensional nonlinear dynamic finite element model with thermal, electrical, and mechanical coupling was established, and the laws describing the macroscopic electrical energy output and thermal stress distribution were derived. The position of the maximum thermal stress changed as the crack size varied. When the crack field axis was increased from 0.2 mm to 1.8 mm, the total output energy increased by 14.4 %, whereas the thermal stress increased to 447 MPa. The total energy growth rate under pulsed heat source conditions reached 52.3 % (from 62.71 J to 95.52 J) compared with that of the steady-state heat source. However, the maximum thermal stress increased by 173.6 % (from 91 MPa to 249 MPa). The results show that the crack and pulsed heat source can effectively improve the electrical output performance of TEGs; however, their mechanical properties deteriorated. This study is useful in terms of predicting the performance of TEGs in practical applications more accurately.

Guidelines for power and time variables for microwave ablation in porcine lung in vitro.

Determination of the appropriate ablative parameters is the key to the success and safety of microwave ablation (MWA) of lung tumors. The purpose of this study was to provide guidelines and recommendations for the optimal time and power for lung tumor MWA. MWA using a 2450-MHz system was evaluated in a porcine lung. The independent variables were power (30, 40, 50, 60, 70, and 80 W) and time (2, 4, 6, 8, 10, and 12 min), and the outcome variable was the volume of ablation. Lung tissues were procured after MWA for measurement and histological evaluation. Analysis of variance was used for statistical analysis, followed by least significant difference (LSD) t-tests where appropriate. A P value of <0.05 was considered statistically significant. The outcome variable (ablative volume) was significantly affected by time, power, and time/power interaction (P < 0.05). When the total output energy was kept constant, the combination of higher power and shorter time obtained a larger ablative volume, especially in the low- and medium-energy groups (P < 0.01). We propose guidelines for ablative volume based on different time and power variables to provide a reference for clinical applications.

Three-Dimensional Finite Element Modeling of the Singer’s Formant Cluster Optimization by Epilaryngeal Narrowing With and Without Velopharyngeal Opening

This study aimed to find the optimal geometrical configuration of the vocal tract to increase the total acoustic energy output of human voice in the frequency interval 2-3.5 kHz “singer’s formant cluster”, (SFC) for vowels [a:] and [i:] considering epilaryngeal changes and the velopharyngeal opening (VPO). The study applied 3D volume models of the vocal and nasal tract based on computer tomography (CT) images of a female speaker. The epilaryngeal narrowing (EN) increased the total sound pressure level (SPL) and SPL of the SFC by diminishing the frequency difference between acoustic resonances F3 and F4 for [a:] and between F2 and F3 for [i:]. The effect reached its maximum at the low pharynx/epilarynx cross-sectional area ratio 11.4:1 for [a:] and 25:1 for [i:]. The acoustic results obtained with the model optimization are in good agreement with the results of an internationally recognized operatic alto singer. With the EN and the VPO, the vocal tract input reactance was positive over the entire fo singing range (ca. 75-1500 Hz). The VPO increased the strength of the SFC and diminished the SPL of F1 for both vowels, but with EN the SPL decrease was compensated. The effect of EN is not linear and depends on the vowel. Both the EN and the VPO alone and together can support (singing) voice production.

Experimental performance evaluation of air-based photovoltaic–thermal collector with rectangular turbulators and longitudinal fins

An air-based photovoltaic–thermal collector (PVTC) simultaneously generates electricity and heats air using energy from incident solar radiation. Its simple design ensures low initial costs and easier maintenance. However, its thermal efficiency is limited by the low heat conductivity of air. To address this shortcoming, considerable research has focused on enhancing either the heat transfer area or the heat transfer coefficient. However, only one of these two methods has typically been utilized, and information regarding PVTCs that incorporate both technologies is lacking. Thus, a novel air-based PVTC featuring longitudinal fins and rectangular turbulators is proposed herein. In this PVTC, the fins enlarge the heat transfer area, while the turbulators improve the heat transfer coefficient by creating turbulence near the fin surface. The proposed PTVC (PTVC-LFRT) was experimentally evaluated under real-world weather conditions and also compared with two other PVTC configurations: one with a smooth air channel (PTVC-SMAC) and one with only fins (PTVC-LF) to reveal the potential thermal and electrical gains achievable with the proposed design. As a result, PVTC-LFRT achieved an electrical efficiency of 17.06 %, whereas PVTC-SMAC and PTVC-LF recorded corresponding values of 16.55 % and 16.8 %, respectively. Moreover, PVTC-LFRT exhibited a thermal efficiency of 38.93 %, while PVTC-SMAC and PVTC-LF achieved thermal efficiencies of 22.68 % and 33.56 %, respectively. Finally, the total daily energy output of PVTC-LFRT from incident solar radiation was 42.73 % and 11.2 % higher than those of PVTC-SMAC and PVTC-LF, respectively. These findings verify that incorporating fins with turbulators into a PVTC effectively enhances its electrical and thermal efficiency. Consequently, the feasibility of the proposed system could be confirmed, and its promotion is considered worthwhile.

Impact of crop rotation and tillage operations on mitigating greenhouse gas emissions and evaluation of sustainability index in rice- wheat-green gram cropping system of north Bihar

In North Bihar (NB), the conventional rice-wheat cropping system has led to soil, water, and environmental degradation, alongside low profitability, threatening sustainability. To address these concerns, a thorough field research was conducted over the course of three years to assess different methods of tillage and crop establishment in a rice, wheat, and greengram cycle. The experiment involved five scenarios with different combinations of crop rotation, tillage techniques, seeding procedures, fertilizer use, and irrigation strategies. Uncertainty analysis showed no significant change in mean and variance estimation among seven scenario replications at 5% significance level. Compared to traditional farming (SN-1), managing DSR-rice (SN-5) increased profitability by 17.56%, improved energy use efficiency (EUE) by 32.16%, and reduced irrigation by 24.76% and global warming potential (GWP) by 23.46%. Similarly, substituting zero tillage wheat (ZTW) SN-5 resulted in comparable profitability gains (18.25%) and significant improvements in irrigation (10 %), EUE (+48.65%), and GWP (−20 %) compared to SN-1. Green gram ZT also showed increased profitability (17.35%), with notable improvements in EUE (+38.31%) and GWP (−12.92%) compared to SN-1. Principal component and correlation analyses revealed relationships between total energy inputs, yields, economic returns, and sustainability indices, highlighting the benefits of crop rotation and tillage practices in optimizing resource use. The study suggests that compared to conventional systems, significant improvements in productivity, profitability, energy-use efficiency, and environmental mitigation can be achieved with Crop Rotation and Tillage Operations techniques.

Enhancing crop production and carbon sequestration of wheat in arid areas by green manure with reduced nitrogen fertilizer

Green manure with appropriate amount of chemical nitrogen fertilizer can increase crop yield, but also aggravate soil carbon emissions. However, it is unclear whether incorporation of green manure into the cropping pattern with reduced nitrogen amount can alleviate this situation and enhance carbon sequestration potential. So, a field experiment with split-plot design was set up in 2018 of northwest China, and studied the effects of nitrogen reduction on crop productivity, carbon emissions, and carbon sequestration potential in 2021–2023. The main plots were two cropping patterns, including multiple cropped green manure after wheat harvest (W-G) and fallow after wheat harvest (W). Three nitrogen application levels formed the split-plots, including local conventional nitrogen amount (N3, 180 kg ha−1), nitrogen amount reduced by 15% (N2, 153 kg ha−1) and 30% (N3, 126 kg ha−1). The results showed that W-G increased grain yield of wheat and energy yield of wheat multiple cropped green manure pattern. The multiple cropped green manure after wheat harvest with local conventional nitrogen amount reduced by 15% (W-GN2) had the significant increasing-effect, and increased grain yield of wheat by 9.6% and increased total energy yields by 39.3% compared to fallow after wheat harvest with local conventional nitrogen amount (W–N3). Relative to W–N3, W-GN2 did not significantly increase carbon emissions of wheat season, and increased total carbon emissions of cropping pattern by 11.1%. Compared to multiple cropped green manure after wheat harvest with local conventional nitrogen amount (W-GN3), W-GN2 decreased carbon emissions by 5.8% in wheat season and decreased by 3.9% in the whole cropping pattern. Therefore, W-GN2 gained high carbon emission efficiency based on grain yield, and were 9.9% and 11.2% higher than W–N3 and W-GN3, respectively. In addition, W-GN2 enhanced soil total nitrogen, carbon, and organic carbon contents, compared with W–N3, thus increasing soil carbon sequestration potential index (net primary productivity/carbon emissions). We conclude that multiple cropped leguminous green manure after wheat harvest with local conventional nitrogen amount reduced by 15% can enhance crop productivity and carbon sequestration potential of farmland in arid areas.

Electro-optical Q-switched laser array with one lamp pumping six Nd:YAG rods for programmable laser reconstruction in space-power-time domains

We report a novel laser array with one lamp pumping six Nd:YAG rods for programmable laser reconstruction in space-power-time domains. A sextuple ellipse pump cavity is proposed, and this scheme permits one xenon flash lamp with advantageously cylindrical pumping characteristics to simultaneously efficiently pump multiple Nd:YAG lasers in a laser system. The experimental setup was designed, and further experiments were carried out. The laser array can stably operate at a pumping rate of 1 Hz-10 Hz. Each laser beam of the six laser outputs has a divergence angle of less than 1.7 mrad, an output pulse of greater than 208 mJ, and a pulse width of approximately 10 ns, corresponding to a pulse peak power of approximately 20 MW. The laser array has a total output energy of 1.53 J at an electrical input of 93.3 J, corresponding to an overall electro-optical conversion efficiency of 1.64 % and an electro-optical slope efficiency of 3.17 %. Finally, laser array output pulses coded modulation in the space-power-time domains are achieved by electro-optical Q-switching. Therefore, the laser array provides the capability for programmable laser reconstruction in the space-power-time domains in a laser system for multipurpose applications, such as energy-tailored material processing, coded pulse laser ranging for improved signal-to-noise ratio (SNR), active optical remote sensing and scientific research.

Numerical analysis of an innovative solar collector utilizing bistable composite laminates and macro fiber composite actuators

Innovative designs for solar collectors have attracted substantial academic and industrial interests owing to the high efficiency of solar panels in the recent past. This paper proposes the analysis and numerical design of a novel solar collector model composed of bistable laminates bonded with Macro Fiber Composite (MFC) actuators and solar cells. The bistable cross-ply laminate serves as the steering mechanism in this design by providing multiple stable shapes for the innovative solar collector design. Bistable morphing structures have received growing interest in aerospace structures and wind turbines due to their rapid shape-changing ability in response to changes in operating conditions, and this paper aims to integrate them more into the solar energy sector. The snap-through and snap-back motion of bistable laminates can be controlled by the voltage inputs of MFC actuators. The change of bistable laminate shape holds the solar cell in a position approximately at the latitude angle of the place to capture maximum solar energy. A systematic finite element parametric study has been performed to identify the optimum size and location of MFC actuators to achieve an energy-efficient snap-through and snap-back transition. As a result, a numerical design of a solar collector with six bistable elements has been proposed. In order to check the feasibility of the proposed designs, a numerical study has been performed to evaluate the total energy output and to optimize the solar panel tilt angle. ASHRAE’s solar irradiation model proposed in the literature has been used to identify the optimum solar panel tilt angle for maximum annual solar irradiation. This innovative solar collector model has demonstrated promising results, holds the potential for widespread application across various engineering domains, and paves the way for increased adoption of intelligent structures in everyday life.

Performance Evaluation of Air-Based Photovoltaic Thermal Collector Integrated with Dual Duct and Semicircular Turbulator in Actual Climate Conditions

An air-based photovoltaic thermal collector (PVTC) is a system that generates both electricity and heat using air flowing over a photovoltaic (PV) module. This system offers the advantage of easy maintenance; however, it suffers from lower thermal efficiency compared to other PVTCs, mostly owing to the low heat capacity of air. Thus, this study introduces a novel PVTC incorporating dual ducts and semicircular turbulators, which were experimentally evaluated under actual weather conditions in the Republic of Korea. The proposed PVTC was compared with two other types of PVTC: one is a single-duct PVTC with semicircular turbulators, and the other is a dual-duct PVTC without turbulators. The results showed that the thermal efficiency of the proposed PVTC increased by approximately 88.7% compared to the single-duct PVTC with a turbulator and by 9.3% compared to the dual-duct PVTC without a turbulator. The electrical efficiency showed a slight decrease of about 7.2% compared to the single-duct PVTC but an increase of 1.4% compared to the dual-duct PVTC without a turbulator. Overall, the total efficiency of the proposed PVTC increased by 54.2% and 7.7% compared to the single-duct PVTC and the dual-duct PVTC without a turbulator, respectively. These experimental results demonstrate that attaching dual ducts and semicircular turbulators to an existing PVTC increases the daily thermal energy output, which ultimately enhances the total daily energy output.

Effect of Crop Establishment Methods and Weed Management Practices on Productivity and Bioenergetics of Rice

Background: SRI and aerobic rice are one of the techniques of growing rice under water scarcity areas where meeting water requirement is becoming a global threat. Weeds are another threat to yield of rice irrespective of different establishment methods. Until checked, it can decline rice yield and quality up to more than 70%. SRI and aerobic rice have different densities of weeds and integrated weed management can be applied to suppress the weeds. Considering the current scenario, research was conducted to investigate growth, yield and bioenergetics of rice under different establishment methods and weed management. Methods: The experiment entitled “Effect of crop establishment methods and weed management practices on productivity and bioenergetics of rice” was carried out in split plot design with main plots, viz., M1- aerobic rice (AR) and M2- system of rice intensification (SRI) and five subplots W1- pre-emergence (pendimethalin @1 kg a.i ha-1) fb post-emergence (bispyribac-sodium @20g a.i ha-1) (PE+POE), W2- pre-emergence (pendimethalin @1 kg a.i ha-1) fb cono weeding at 15, 30, and 45 DAT/ DAS (PE+CW), W3- weed free (WF), W4- weedy check (WC), W5- stale seedbed followed by post-emergence herbicide (bispyribac-sodium 10% SC 20 g a.i ha-1) (SSB+POE) in split plot design with three replications taking the variety ‘Pusa Basmati-1121’ as a test crop. Result: Among the establishment methods, SRI recorded significantly higher growth attributes like plant height and dry matter production and yield attributes like number of panicles per hill, panicle length, number of grains per panicle, test weight, grain yield, straw yield, biological yield, and harvest index. Among the weed management treatments, WF recorded significantly higher growth attributes like plant height, number of tillers per hill, dry matter production and yield attributes like number of panicles per hill, panicle length, number of grains per panicle, test weight, grain yield, straw yield, biological yield, and harvest index that was followed by treatment PE+CW. Maximum net return and B:C ratio was observed in the treatment combinations M2W2- SRI + (PE+CW). The maximum total energy input was found in the treatment combination M1W1- AR+ (PE+POE) and the maximum total energy output was found in the treatment combination M2W3- SRI + WF. The energy intensiveness was observed to be maximum in the treatment combination M1W4- AR + WC and the maximum energy efficiency index was observed in the treatment combination M2W3- SRI+WF.

Revisiting the Constraint on the Equation of State of Neutron Stars Based on Binary Neutron Star Mergers

The merger of a neutron star (NS)–NS binary can form different productions of compact remnants, among which a supramassive NS (SMNS) can create an internal plateau, and the following steep decay marks the collapse of the SMNS. The proportion of the SMNS and the corresponding collapse time are often used to constrain the NS equation of state (EOS). This paper revisits this topic by considering the effect of an accretion disk on a compact remnant, which is not considered in previous works. Compared with previous works, the collapse-time distribution (peaks ∼100 s) of SMNSs formed from an NS–NS merger is almost unaffected by the initial surface magnetic field (B s,i ) of the NS, but the total energy output of the magnetic dipole radiation from the SMNSs depends on B s,i significantly. Coupling the constraints from the SMNS fraction, we exclude some EOSs and obtain three candidate EOSs, i.e., DD2, ENG, and MPA1. By comparing the distributions of the collapse time and the luminosity of the internal plateau (in the short gamma-ray bursts) for observations obtained based on the three candidate EOSs, it is shown that only the EOS of ENG is favored. Our sample, based on the ENG EOS and a mass distribution motivated by Galactic systems, suggests that approximately 99% of NS–NS mergers collapse to form a black hole (BH) within 107s. This includes scenarios promptly forming a BH (36.5%), an SMNS (60.7%), or a stable NS that transitions into a BH or an SMNS following accretion (2.1%). It also indicates that the remnants for GW170817 and GW190425, and the second object of GW190814, are more likely to be BHs.

Application of resource-environmental-economic perspective for optimal water and nitrogen rate under high-low seedbed cultivation in winter wheat

High-low seedbed cultivation (HLSC), a targeted agricultural method for increasing land utilization efficiency in North China Plain, has emerged as a key practice in enhancing sustainable agriculture, particularly in the context of the region’s unique ecological challenges and water scarcity. However, comprehensive analysis of resource-environment-economy for water and nitrogen strategy in HLSC-cultivated wheat was limited. A three-year field experiment with four nitrogen rates (360, 300, 240, and 180 kg ha−1, denoted as N1, N2, N3, and N4) and three irrigation quotas (120, 90, and 60 mm, referred to as W1, W2, and W3) was conducted to investigate effects of water and nitrogen rate on water productivity (WP), agronomic efficiency of nitrogen (AEN), energy use efficiency (EUE), carbon footprint (CF), water footprint (WF), nitrogen footprint (NF), and net benefits of HLSC-cultivated wheat. Results showed that the total energy output in moderate water and nitrogen input (i.e., N3W2) was 328.0×103 MJ ha−1, which was significantly increased by 31.8% compared with lower input (i.e., N4W3) but was decreased by 17.1% compared with higher input (i.e., N1W1). The total energy input, water consumption and grain yield in N3W2 was decreased by 22.3%, 14.4 and 4.1%, relative to N1W1, respectively, and increased by 18.2%, 20.8% and 42.2% relative to N4W3, respectively. This may lead to significant increase in EUE, WP, AEN and net income in N3W2. Furthermore, the CF, WF, and NF increased as the water and nitrogen input increased, whereas minimum CF, WF and NF per unit of yield was obtained N3/N4 or W1/W2 level. 240 kg N ha−1 coupled with 90–120 mm irrigation quota was recommended by TOPSIS for the HLSC-cultivated wheat to best trade-off resource use efficiencies, environmental footprints, and net benefits. Future studies are needed to further assess the scalability and adaptability of HLSC-cultivated wheat across different climatic zones and soil types.

Artificial ground reflector size and position effects on energy yield and economics of single‐axis‐tracked bifacial photovoltaics

AbstractArtificial ground reflectors improve bifacial energy yield by increasing both front and rear‐incident irradiance. Studies have demonstrated an increase in energy yield due to the addition of artificial reflectors; however, they have not addressed the effect of varying reflector dimensions and placement on system performance and the impact of these parameters on the reflectors' financial viability. We studied the effect of high albedo (70% reflective) artificial reflectors on single‐axis‐tracked bifacial photovoltaic systems through ray‐trace modeling and field measurements. In the field, we tested a range of reflector configurations by varying reflector size and placement and demonstrated that reflectors increased daily energy yield up to 6.2% relative to natural albedo for PERC modules. To confirm the accuracy of our model, we compared modeled and measured power and found a root mean square error (RMSE) of 5.4% on an hourly basis. We modeled a typical meteorological year in Golden, Colorado, to demonstrate the effects of artificial reflectors under a wide range of operating conditions. Seventy percent reflective material can increase total incident irradiance by 1.9%–8.6% and total energy yield by 0.9%–4.5% annually after clipping is considered with a DC–AC ratio of 1.2. Clipping has a significant effect on reflector impact and must be included when assessing reflector viability because it reduces reflector energy gain. We calculated a maximum viable cost for these improvements of up to $2.50–4.60/m2, including both material and installation, in Golden. We expanded our analysis to cover a latitude range of 32–48°N and demonstrated that higher‐latitude installations with lower energy yield and higher diffuse irradiance content can support higher reflector costs. In both modeling and field tests, and for all locations, the ideal placement of the reflectors was found to be directly underneath the module due to the optimized rear irradiance increase.

Effect of long-term application of fertilizers on the yield and energy productivity of sugar beet

Effect of long-term application of fertilizers on the yield and energy productivity of sugar beet

Thermal analysis and dynamic attributes of a sustainable CSP-fossil hybrid power plant utilizing organic Rankine cycles for enhanced plant performance

The increasing global demand for energy, driven by population growth, highlights the need for sustainable solutions to ensure a sustainable future. This article outlines the design and optimization process of a 1 MW CSP-Fossil hybrid power plant that examines the utilization of toluene and cyclohexane as working fluids within three distinct Organic Rankine cycle (ORC) configurations (simple, recuperated, and with Open Feed Organic Heater). This study aims to propose a sustainable and effective solution for satisfying energy needs while addressing the intermittent nature of solar resources by enhancing system architecture and incorporating fossil fuel technologies. The solar field design has been based on a Concentrated Solar Power (CSP) system, which generated 44% of the total energy output from renewable solar sources. The analysis takes into consideration a selection of criteria, notably thermal efficiency, overall efficiency, power generation capacity, and cost-effectiveness. The selection of relevant performance indicators, evaluation of alternative ORC configurations and working fluids, and optimization of the solar multiple and thermal storage capacity are included among the criteria for conducting the parametric investigation. Based on the investigation, it has been determined that the ORC configuration, which includes a recuperator and utilizes cyclohexane as the working fluid, demonstrates the most favorable design. This configuration offers enhanced efficiency and improved performance. Additionally, it is determined that a solar multiple value of 1.7 and the integration of a 12-hour thermal energy storage system are optimal. This led to a 4-5 hour increase in the availability of daily power generation, thereby improving the reliability and flexibility of the CSP plant. The incorporation of fossil fuels into the hybrid CSP-Fossil plant results in a notable enhancement of the Capacity Utilization Factor (CUF). This improvement guarantees uninterrupted energy generation even when solar resources are limited. The implications of the findings are significant for the future development of CSP systems. These findings provide valuable insights into enhancing energy efficiency and tackling sustainability challenges.

Effects of thermoelasticity induced aperture variation on performances of Enhanced geothermal system

Geothermal energy, as one of the renewable energy types, has great potential to balance the variable energy supply from photovoltaic and wind energy types. This, however, requires the development of an Enhanced Geothermal System (EGS). Injecting cold water into deep geo-reservoirs induces thermoelastic deformation and changes the fracture apertures, which may significantly affect the EGS lifetime and energy performance. In this case, this study develops a fully coupled thermal–hydraulic-mechanical model to investigate the impacts of temperature, pressure, and aperture heterogeneity on the alterations of fracture aperture. Then, considering the reservoir lifespan, the research takes a further step into the influence of heterogeneous aperture variation on EGS production temperature and long-term energy performance. Results show that aperture significantly varies once a temperature breakthrough occurs in the production well for both homogeneous and heterogeneous aperture fields. The thermoelasticity-induced aperture variations enhance water flow rate, leading to a considerable increase in reservoir heat production rate, but a shorter EGS lifespan. Furthermore, temperature variation shows a more substantial influence on aperture alteration compared to pressure change. Additionally, a sensitivity analysis indicates that the 30-year total energy output is proportional to the injection/production pressures and injection temperatures. However, the fracture with either excessively large or small initial apertures leads to worse EGS energy performance.

THE INFLUENCE OF TILT ANGLE ON THE DAILY PROFILE TOTAL ENERGY OF PHOTOVOLTAIC POLYCRYSTAL

This preliminary study aims to determine the daily profile of the power output generated from solar panels, with variations in the house’s roof angles of 15º, 0º, 15º. Tilt angle investigation expects to discover the impact of placing solar panels on the slope of the tile used on the house’s roof. The collecting data of this study was investigated the data of current and voltage every hour that produced by solar panel. Besides, this study also comparing the result of total energy output value for daily profile of solar panel during ten hour per day (start from 7 am to 5 pm). The results show that solar panels with an angle of -15º at 07:00 – 10:00 WIB have higher output voltage and current than other angle variations. At a tilt angle of 0º, the output voltage and current of the solar panel are higher at 11:00-14:00 WIB, while at a tilt angle of 15º in the afternoon. Based on observations, each solar panel with exposure for 10 hours obtained the total energy value for polycrystalline solar panels with a tilt angle of -15º of 258.44 Wh, solar panels with an angle of 0º obtained an energy value of 263.64 Wh, and a tilt angle of 15º obtained energy values 260.69 Wh. The photonic energy emitted for 10 hours is 2097.47 Wh. The energy efficiency value for each polycrystalline solar panel is 12.32% for the angle of -15º, the angle of 0º is 12.57%, and 12.43% for the angle of 15º. In conclusion, variations in the angle of the solar panels have significant effect on the voltage, current, and energy generated from polycrystalline solar panels in every hour. However, based on the data result the total energy exposure and the efficiency value for each variation angle has no significant different. Pyramid-shaped house roof construction has the advantage of increasing the value of the cross-sectional area of the tile, which has the opportunity to install wider-sized solar panels so that a greater value of electrical energy is obtained.