Search Results (13)

Characterizing both the CO₂ distribution and wind dynamics in the Martian mesosphere and lower thermosphere is vital for planetary atmospheric science and mission planning. In this work, we propose a novel dual-channel passive limb-viewing imaging system designed to simultaneously observe partial CO₂ column density and line-of-sight (LOS) wind speed from ultraviolet and visible airglow emissions under dayside and terminator illumination conditions. A dichroic beam splitter separates the ultraviolet and visible channels, ensuring high optical throughput and independent optimization of both subsystems. The ultraviolet channel targets O(¹S) 297.2 nm emission, a well-established Martian limb emission driven by CO₂ photodissociation under solar Lyman-α flux. By applying narrow-band imaging and brightness inversion, this channel provides quantitative constraints on CO₂ column density with a stable and well-defined response function. In the visible channel, we introduce a lens array-based compact static Michelson interferometer optimized for the O(¹S) 557.7 nm green line emission, which has been observed in the Martian dayside limb, providing Doppler wind measurements in the 60–180 km altitude range. Radiative transfer simulations using Mars Climate Database indicate retrieval precisions of ±6~8% for CO₂ column density and better than ±5 m/s for wind speed within the primary emission layer (approximately 60–160 km) under representative dayside limb conditions. This dual-parameter remote sensing concept simultaneously constrains the composition and dynamics of the Martian mesosphere and lower thermosphere region, addressing a long-standing observational gap. The compact and modular design of the system makes it well suited for future Mars orbiter payloads under nominal dayside and terminator observation geometries, providing critical data for validating global circulation models and supporting future entry, descent, and landing system design. Full article

This study evaluated the performance of a hybrid heat pump system integrating photovoltaic–thermal (PVT) panels with a standing column well (SCW) geothermal system in a strawberry greenhouse. The PVT panels, installed over 10% of the area of a 175 m³ greenhouse, stored excess solar heat in an aquifer to offset the reduced efficiency of the geothermal source during extended operation. The results showed that the hybrid system can supply 11,253 kWh of heat energy during the winter, maintaining the night time indoor temperature at 10 °C even when outdoor conditions dropped to −10.5 °C. The PVT system captured 11,125 kWh of solar heat during heating the off season, increasing the heat supply up to 22,378 kWh annually. Additionally, the system generated 3839 kWh of electricity, which significantly offset the 36.72% of the annual pump system electricity requirements, enhancing the system coefficient of performance (COP) of 3.38. Strawberry production increased by 4% with 78% heating cost saving compared to a kerosene boiler system. The results show that the PVT system effectively supports the geothermal system, improving heating performance and demonstrating the feasibility of hybrid renewable energy in smart farms to enhance efficiency, reduce fossil fuel use, and advance carbon neutrality. Full article

Ocean wave energy has emerged as a promising source in the pursuit of sustainable energy solutions, with Oscillating Water Column (OWC) systems standing out due to their simplicity and potential. This study analyzes how the geometric and physical parameters of the OWC chamber influence internal airflow dynamics, a key factor in the performance of the Wells turbine. The methodology includes a mathematical approximation, the definition of chamber geometry, and the design parameters of both the chamber and the Wells turbine. Three configurations were evaluated using Computational Fluid Dynamic (CFD) simulations. The impact of key variables such as chamber inclination and cross-sectional shape on air velocity and pressure at the turbine inlet was assessed. The results indicate that, among cylindrical, inclined cylindrical, and rectangular configurations, the inclined cylindrical chamber design significantly enhances airflow stability and turbine efficiency. These findings offer valuable insights for enhancing the overall performance of OWC based energy systems. Full article

Current super-resolution algorithms exhibit limitations when processing noisy remote sensing images rich in surface information, as they tend to amplify noise during the recovery of high-frequency signals. To mitigate this issue, this paper presents a novel approach that incorporates the concept of compressed sensing and explores the super-resolution problem of remote sensing images for space cameras, particularly for high-speed imaging systems. The proposed algorithm employs K-singular value decomposition (K-SVD) to jointly train high- and low-resolution image blocks, updating them column by column to obtain overcomplete dictionary pairs. This approach compensates for the deficiency of fixed dictionaries in the original algorithm. In the process of dictionary updating, we innovatively integrate the circle chaotic mapping into the solution process of the dictionary sequence, replacing pseudorandom numbers. This integration facilitates balanced traversal and simplifies the search for global optimal solutions. For the optimization problem of sparse coefficients, we utilize the orthogonal matching pursuit method (OMP) instead of the L1 norm convex optimization method used in most reconstruction techniques, thereby complementing the K-SVD dictionary update algorithm. After upscaling and denoising the image using the dictionary pair mapping relationship, we further emphasize image edge details with local gradients as constraints. When compared with various representative super-resolution algorithms, our algorithm effectively filters out noise and stains in low-resolution images. It not only performs well visually but also stands out in objective evaluation indicators such as the peak signal-to-noise ratio and information entropy. The experimental results validate the effectiveness of the proposed method in super-resolution remote sensing images, yielding high-quality remote sensing image data. Full article

This perspective describes different schemes of power systems integration for various process technology in oil refining and petrochemistry with a focus on distillation. An overview is given of different methods of gas turbines and turboexpanders. Application of the organic Rankine cycle is considered for distillation processes, especially for unconventional schemes, which are integrated into the main process as stand-alone ones, as well when the working fluid of an energy system is a process stream per se. Despite a more complex structure and potential interference with the main process, such schemes are advantageous in terms of more efficient equipment utilization. Integration of turboexpanders in separation processes and in reactor units can improve energy generation efficiency 2–3 fold compared with traditional schemes of energy generation from fossil feedstock. From the economic viewpoint for distillation columns, total annual costs can be decreased by ca. 5–15% with the specific costs of additional generated electricity being very close to the costs of a heating utility. Full article

A review of different energy components is detailed, as a baseline of fundamentals for the new integrated energy concept idealization. This innovative solution is a Hybrid for Renewable Energy Network (Hy4REN) based on well-studied elements to produce the best final solution. This proposal has the objective of improving energy system sustainability, facing fossil fuel and climate change restrictions, and increasing energy network flexibility. The most mature energy storage technology, pumped hydropower energy storage (PHES), is used to support both the grid connection and stand-alone modes, as an integrated hybrid energy system. The hybrid system idealization is modular and scalable, with a complementary nature among several renewables, using sea water in offshore mode to build an integrated solution. By evaluating a variety of energy sources, complemented with economic analysis, the benefits associated are evidenced using this sustainable methodology based only on renewable sources. Combined production of hydropower, using sea water, with pumped storage and water hammer events to create potential energy to supply hydropower in a water loop cycle, without consuming electrical energy, is explored. Other renewable sources are also integrated, such as floating solar PV energy and an oscillating water column (OWC) with coupled air-venting Wells and wind turbines, all integrated into the Hy4REN device. This complementarity of available sources allows us to improve energy storage flexibility and addresses the energy transition toward net-zero carbon emissions, inducing significant improvements in the sustainability of the energy network as a whole. Full article

This study proposed a technology to improve the performance characteristics and coefficient of performance (COP) of a geothermal system by fundamentally preventing underground water discharge and maintaining a constant temperature of the underground heat exchanger composed of bleed discharge water that utilizes two balancing wells using cross-mixing methods. Using the standing column well (SCW) and cross-mixing balancing well underground heat exchanger, we compared and analyzed the effective thermal conductivity characteristics and COP characteristics during heating and cooling modes. Consequently, the cross-mixing balancing well underground heat exchanger exhibited more effective thermal conductivity than the SCW underground heat exchanger, with a high COP. Therefore, suggesting the performance was improved using groundwater flow rather than SCW. The comparison and analysis results of the effective heat map characteristics using the results of the SCW and balancing well system showed that the heating operation for the SCW underground heat exchanger had better thermal conductivity characteristics than the cooling operation. In addition, regarding a balancing well underground heat exchanger, the cooling operation exhibited superior thermal conductivity characteristics. Thus, the performance was considered to have improved due to the flow of activated groundwater in the ground and the rapid heat transfer without heat accumulation. Full article

The Lorraine–Saar Basin is one of the largest geologically and commercially important Paleozoic coal-bearing basins in Western Europe and has considerable coal reserves in numerous coal beds. The basin stands out due to its sedimentary column of up to 6 km and its inversion, resulting in Paleozoic low-amplitude erosion at around 750 m (French part of the basin) and pre-Mesozoic (Permian) erosion between 1800 and 3000 m (the Saar coalfield or German part of the basin). Thermal maturation of organic matter in sedimentary clastic rocks and coal seams has led to the formation of prolific coalbed methane (CBM) plays in many domains throughout the Carboniferous Westphalian and Stephanian sequences. Coal mines here are no longer operated to produce coal; however, methane generated in “dry gas window” compartments at a depth exceeding 3.5 km has escaped here via several major faults and fracture corridors forming “sweet spot” sites. Faults and a dense network of tectonic fractures together with post-mining subsidence effects also increased the permeability of massive coal-bearing and provided pathways for the breathing of environmentally hazardous mine gases. Nearly all CBM plays can be classified as naturally fractured reservoirs. The Lorraine–Saar Basin is not excluded, indeed, because of the experience of geological surveys during extensive coal-mining in the past. The knowledge of geometrical features of fracture patterns is a crucial parameter for determining the absolute permeability of a resource play, its kinematics environment, and further reservoir simulation. The main focus of this contribution is to gain an insight into the style and structural trends of natural cleat patterns in the basin based on the results of X-ray computer tomography (CT) to ensure technical decisions for efficient exploration of CBM reservoirs. To explore the architecture of solid coal samples, we used X-ray CT of a coal specimen collected from Westphalian D coal from exploratory well Tritteling 1. The studied coal specimen and its subvolumes were inspected in three series of experiments. At different levels of CT resolutions, we identified two quasi-orthogonal cleat systems including a smooth-sided face cleat of tensile origin and a curvilinear shearing butt cleat. The inferred cleat patterns possess features of self-similarity and align with directional stresses. Results of the treatment of obtained cleat patterns in terms of their connectivity relationship allowed the presence of interconnected cleat arrays to be distinguished within studied samples, potentially facilitating success in CBM extraction projects. Full article

Standing column well (SCW) geothermal heat exchanger permits a bleeding discharge of less than 20% in the event of a maximum load, which is an inappropriate method of using underground water. In this study, the existing operational method of two adjacent SCW geothermal heat exchangers, each with a single well, was modified. This technology aims to improve the coefficient of performance (COP) of the geothermal system by fundamentally preventing underground water discharge and maintaining a constant temperature of the underground heat exchanger. To curb the bleed water discharge, two balancing wells of cross-mixing methods were employed. The result of the cooling and heating operations with the existing SCW heat exchange system and the balancing well cross-combined heat exchange system showed that the measured COP increases by 23% and 12% during the cooling and heating operations, respectively. When operating with a balanced well cross-mixed heat exchange system, the initial temperature of the underground was constant with a small standard deviation of 0.08–0.12 °C. Full article

Standing column well constitutes a recent promising solution to provide heating or cooling and to reduce greenhouse gases emissions in urban areas. Nevertheless, scaling issues can emerge in presence of carbonates and impact their efficiency. Even though a thermo-hydro-geochemical model demonstrated the impact of the water temperature on carbonate concentration, this conclusion has not been yet demonstrated by field investigations. To do so, an experimental ground source heat pump system connected to a standing column well was operated under various conditions to collect 50 groundwater samples over a period of 267 days. These field samples were used for mineral analysis and laboratory batch experiments. The results were analyzed with multivariate regression and geochemical simulations and confirmed a clear relationship between the calcium concentrations measured in the well, the temperature and the calcite equilibrium constant. It was also found that operating a ground source heat pump system in conjunction with a small groundwater treatment system allows reduction of calcium concentration in the well, while shutting down the system leads to a quite rapid increase at a level consistent with the regional calcium concentration. Although no major clogging or biofouling problem was observed after two years of operation, mineral scales made of carbonates precipitated on a flowmeter and hindered its operation. The paper provides insight on the impact of standing column well on groundwater quality and suggests some mitigation measures. Full article

In this study, a mobile measuring device was developed and a thermal response test that applied a standing column well-type heat exchanger was conducted to obtain design parameters from field measurements. The main purpose of this study was to investigate the effects of thermal conductivity and geothermal resistance on site, including the flow and effects of natural convection of groundwater in boreholes. We compared, analyzed, and investigated the effective thermal conductivity of a borehole heat exchanger system and the effective thermal conductivity that was not applied when bleeding single-well standing column wells (SCWs), which is called an open-type standing column well geothermal heat exchanger system. We also investigated the heat transfer characteristics during the bleeding of two-well type SCWs, where water is injected from one clearing hole to the returning hole depending on the bleeding rate. Artificial recharging was used to inject the change of thermal conductivity from the bleeding rate of a geothermal heat exchanger into another SCW type. From the comparison results of the thermal conductivity of the multi-well and single-well underground heat exchangers, four times higher efficiency than the single-well was obtained. The reason for this is considered to be energy utilization utilizing groundwater energy. Full article

Groundwater heat pump systems (GWHPs) can achieve higher coefficient of performance (COP) than air-source heat pump systems by using the relatively stable temperature of groundwater. Among GWHPs, multi-well systems have lower initial investment costs than conventional closed-loop geothermal systems, because they typically require installation of fewer boreholes for the same building load. However, the performance of GWHPs depends significantly on the groundwater properties, such as groundwater temperature, permeability and water quality. Moreover, pumping and injecting of groundwater during long-term operation may lead to problems such as overflow or clogging of the wells. In order to ensure reliable energy from ground sources, the development of sustainable operation methods for multi-well systems is essential for preventing overflow and well clogging. In this study, we have developed a pairing technology that connects the injection and supply wells through a spillway. This pairing technology can be used to control groundwater levels in wells and can be sustainably operated. To accurately estimate the performance of a multi-well system with the proposed pairing technology, the heating and cooling performance of the developed system was compared to that of a standing column well (SCW) system in a field-scale experiment. Furthermore, the effects of the multi-well pairing system on groundwater levels in the injection well were analyzed by numerical simulation. Moreover, in order to decide the required conditions of the multi-well pairing system, case studies were conducted under various hydraulic conductivity and pumping conditions. Full article

Deep geothermal heat pump systems have considerable energy saving potential for heating and cooling systems that use stable ground temperature and groundwater as their heat sources. However, deep geothermal systems have several limitations for real applications such as a very high installation cost and a lack of recognition as heating and cooling systems. In this study, we performed a feasibility assessment of a Standing Column Well (SCW) system using a deep geothermal well, based on a real-scale experiment in Korea. The results showed that the temperature of the heat source increased up to 42.04 °C in the borehole after the heating experiment, which is about 30 °C higher than that of normal shallow geothermal wells. Furthermore, the coefficient of performance (COP) of the heat pump during 3 months of operation was 5.8, but the system COP was only 3.6 due to the relatively high electric consumption of the pump. Moreover, the payback period of the system using a deep well for controlled horticulture in a glass greenhouse was calculated as 6 years compared with using a diesel boiler system. Full article