Storage Volume Research Articles

Optimizing the thermal energy storage performance of shallow aquifers based on gray correlation analysis and multi-objective optimization

The operation parameters and well layout parameters of aquifer thermal energy storage (ATES) system directly influence the thermal energy storage performance. How to optimize the parameters to obtain the optimal process scheme is of great significance to promote the field application of ATES. Taking the thermal storage performance of shallow aquifer as the optimization objective, this paper compares the influence degrees of key factors on thermal storage performance by means of gray correlation analysis (GCA), and prepares the optimal thermal storage scheme by using the multi-objective optimization method. The following results are obtained. First, the great difference between inlet temperature and aquifer weakens the thermal storage capacity of the system, while the thermal interference between thermal storage wells of the same type is favorable for thermal storage capacity instead. Second, aquifer thickness and well number have a greater impact on the thermal loss rate, while injection rate and well spacing have a significant influence on the thermal recovery rate. The inlet temperature has the least effect on both of them. Third, the optimal thermal storage scheme is the single well system with inlet temperature of 25 °C, aquifer thickness of 106.597 m and injection rate of 30 kg/s. In conclusion, the influence degrees of the key parameters on thermal loss rate and thermal recovery rate are different, so in order to improve the thermal storage performance, equilibrium optimization is necessary between both of them. In addition, the optimization scheme effectively expands the thermal storage volume, and reduces the heat loss while improving the thermal recovery, with thermal loss rate and thermal recovery rate of the whole system optimized by 12.69% and 3.19% respectively on the basic case, which can provide a reference for the rational design of ATES system.

A flat-foldable equiangular spiral folding pattern inspired by sunflowers for deployable structures

Flasher origami pattern has been widely utilized to improve the stowage efficiency of deployable structures. Nevertheless, flasher origami cannot be folded fully flat, and they still have great potential for optimization in terms of storage volume and folding creases. In this paper, a flat foldable equiangular spiral folding pattern inspired by the sunflower disk is introduced. Then, a parametric design method for this equiangular spiral crease diagram is introduced in detail. Subsequently, a kinematic model of the equiangular spiral folding pattern is established based on the kinematic equivalence between rigid origami and spherical linkages. A simulation of the developed model demonstrates that the equiangular spiral folding pattern can be folded flat. Using the folded ratio as an evaluation index, the calculated results and experiments show that the equiangular spiral crease pattern can yield fewer creases and improve stowage efficiency in comparison to flasher origami pattern. Equiangular spiral folding pattern can save a considerable amount of space and provide a new approach to spatially deployable structures.

Tidal energy extraction modifies tidal asymmetry and transport in a shallow, well-mixed estuary

Tidal energy extraction is increasingly being studied as a potential renewable energy resource in estuaries worldwide. Although it is understood that energy extraction via tidal stream turbines can modify currents and transport within estuaries, it is not clear how the underlying nonlinear physical mechanisms dictating tidal hydrodynamics are modulated. This research investigates the influence of a hypothetical tidal stream turbine array on barotropic tidal processes in a shallow, well-mixed system: the Piscataqua River – Great Bay (PRGB) estuary, using a numerical model. The modeled turbine farm includes 180 turbines which would extract an estimated 44.7 GWh of energy, annually. The tidal hydrodynamic model for the existing condition is validated with in-situ observations of currents and water level before analyzing tidal asymmetry and transport with and without tidal turbines. Results indicate that the tidal turbine array will decrease tidal elevation and current magnitudes system-wide, but generally reduce ebb currents and transport more than flood over most of the estuary footprint, thereby diminishing tidal asymmetry. The smaller asymmetric distortion compared to the no-turbine case is attributed to reductions in the storage volume of water over the estuary’s extensive tidal flat regions between low and high waters which decreases the associated nonlinear intertidal storage mechanism up to 25%. This leads to weakened ebb dominance over estuary sections from the mouth to mid-reaches, where depths are deep enough to keep the combined nonlinear shallow water and frictional effects from asserting control over the storage mechanism. Even in upstream shallow regions where depth-dependent friction controls asymmetry in both cases, the frictional mechanism is reduced only by 10% with turbines. Some environmental considerations of this work are discussed, with focus on sediment transport, water quality, and ecology.

Statistical Considerations for Analyzing Data Derived from Long Longitudinal Cohort Studies

Modern science is frequently based on the exploitation of large volumes of information storage in datasets and involving complex computational architectures. The statistical analyses of these datasets have to cope with specific challenges and frequently involve making informed but arbitrary decisions. Epidemiological papers have to be concise and focused on the underlying clinical or epidemiological results, not reporting the details behind relevant methodological decisions. In this work, we used an analysis of the cardiovascular-related measures tracked in 4–8-year-old children, using data from the INMA-Asturias cohort for illustrating how the decision-making process was performed and its potential impact on the obtained results. We focused on two particular aspects of the problem: how to deal with missing data and which regression model to use to evaluate tracking when there are no defined thresholds to categorize variables into risk groups. As a spoiler, we analyzed the impact on our results of using multiple imputation and the advantage of using quantile regression models in this context.

A probabilistic approach to stormwater runoff control through permeable pavements beneath urban trees

One of the most current and urgent challenges is making cities sustainable and resilient to climate change. From this perspective, Nature-Based Solutions (NBSs) are well-recognized strategies for stormwater control and water cycle restoration. Urban trees are an example of NBS. However, the high degree of soil sealing typically found in urban environments limits natural processes such as infiltration and hinders the water and nutrient supply for proper root development, which weakens tree stability. Permeable pavements at the base of urban trees, on the one hand, facilitate infiltration, which helps runoff control, and on the other hand, improve stormwater retention and soil humidity, which enhance root feeding.This paper proposes an analytical-probabilistic approach to estimate the contribution of permeable pavements to stormwater management. The equations developed in this study relate the runoff probability to the storage volume, the infiltration rate into the underlying soil, and the average values of the hydrological variables in the input. The model allows us to select different runoff thresholds and considers the possibility that residual volume from previous rainfall events prefills the storage capacity.An application to a case study in Sao Paulo (Brazil) has been presented. It investigates the influence of the different parameters used in the model on the results. The comparison of the outcomes obtained using the developed equations with those obtained from the continuous simulation of measured data confirmed the effectiveness of the proposed analytical-probabilistic approach and the suitability of using permeable pavements at the base of urban trees for improving stormwater retention.

A closer look at Toronto's water quality control design criteria for bioretention cells

Bioretention cells in the Toronto region are usually sized to accommodate runoff from the 90th percentile storm, which has a depth of about 25 mm. This research examines the water quality control performance and cost of bioretention cells sized to satisfy alternative design criteria ranging from 5 to 50 mm. The long-term average runoff-capture efficiencies provided by representative bioretention cells are determined, and their capital as well as operation and maintenance costs are estimated. Results indicate that the current design criterion of 25 mm is probably too high and not cost-efficient. In fact, above some threshold levels, little improvement in runoff-capture and pollutant removal performances may be achieved if the design criterion is increased further, but cost would still linearly increase. Presented here is a methodology that can be used to properly consider both the performance and cost of bioretention cells for establishing a more cost-efficient design criterion. It is shown that a more cost-efficient design criterion for Toronto could be lower than the current one, and significant cost savings can be realized if a lower design criterion is implemented. Some inappropriate ways of quantifying the effective volume of storage provided by bioretention cells are also identified in this paper.

Time-of-flight spectroscopy of ultracold neutrons at the PSI UCN source

The ultracold neutron (UCN) source at the Paul Scherrer Institute (PSI) provides high intensities of storable neutrons for fundamental physics experiments. The neutron velocity spectrum parallel to the beamline axis was determined by time-of-flight spectroscopy using a neutron chopper. In particular, the temporal evolution of the spectrum during neutron production and UCN storage in the source storage volume was investigated and compared to Monte Carlo simulation results. A softening of the measured spectrum from a mean velocity of 7.7(1)–5.1(1) hbox {m s}^{-1} occurred within the first 30 hbox {s} after the proton beam pulse had impinged on the spallation target. A spectral hardening was observed over longer time scales of one measurement day, consistent with the effect of surface degradation of the solid deuterium moderator.

Sustainable Porous Scaffolds with Retained Lignin as An Effective Light-absorbing Material for Efficient Photothermal Energy Conversion.

Organic phase change materials (PCMs) are promising to utilize thermal energy from solar radiation for photothermal energy conversion. However, the issues of poor photo absorption and liquid leakage greatly restrict their practical application. Herein, a sustainable porous scaffold comprising periodate oxidized wood (POW) as the supporting material and in situ retains lignin as the light-absorber dopant are demonstrated. The π-π stacking ability of lignin molecules endows the retained lignin with efficient photonic energy harvesting characteristics for fast thermal conductivity to reach a higher maximal energy storage volume. The inherently porous structure of the POW scaffold enables excellent shape-stability, which bypasses the liquid leakage problem. The resulting POW/PCM composites exhibit superior comprehensive performance, including enhanced light absorption capacity, high photothermal conversion efficiency (≈86.7%), and high latent heat of 151 J g-1 . Furthermore, the POW/PCM composites also possess the ability to maintain a relatively constant indoor temperature when fixed atop the model house roof, showing great potential for their practical applications in the thermal regulation of intelligent buildings. This work not only paves a new way to obtain sustainable and effective porous scaffolds for sufficient photothermal energy conversion but also provides more possibilities for their practical application in the future.

Umbilical Cord Blood Processing Techniques and Their Comparative Advantages: A Review

Background: Umbilical Cord Blood (UCB) has steadily gained prominence in haematopoietic stem cell transplantation (HSCT). Despite UCB advantages, the main disadvantage of UCB in haematopoietic stem cell transplantation (HSCT) is its limited cell dose. Initially, UCB used to be processed and then made to undergo cryopreservation as whole cord blood banking leading to the problem of storing sufficiently large number of cryoprotected UCB units which requires vast amounts of costly storage space in liquid nitrogen. The sole purpose of processing is to concentrates the stem cells and reduce the volume for storage. Different UCB processing methods have been developed. 
 Aim: This review is aimed at bringing together the literature on the different processing methods and highlighting the underlying principles of each method, the relative efficiency and advantages of the methods.
 Methodology: The work involved mainly the critical review of all available academic, professional and industry documents on cord blood processing. The relevant information was obtained from textbooks, academic journals, conference proceedings, the internet among others. The major UCB processing methods include Plasma Depletion, Density Gradient Centrifugation (DGC), Hetastarch, PrepaCyte-CB and Sepax. A study of the potential impact of Hetastarch and PrepaCyte processing methods on transplantation outcomes revealed no difference that was significant was observed between patients receiving cells after the processing regimens were compared.
 Results: A comparison of the engraftment time of PrepaCyte-CB with five other processing methods revealed a quicker engraftment time for PrepaCyte-CB processed cord blood units compared to other processing methods. PrepaCyte-CB also recovers significantly more viable stem cells than AutoXpress (AXP) and hydroxyethyl starch (HES) processing methods. Other workers demonstrated that Sepax depletion produces higher recovery of cells that are nucleated. The effect initial volume of cord blood had on the recovery of nucleated cells for the different method of processing were also compared. Recovery when using Sepax is reduced as the unit size processed increases. Hetastarch, which is a density gradient, and plasma depletion separation is also affected in like manner, however, processing done using PrepaCyte-CB was not affected by the initial volume of the collected unit. The advantage of Sepax is that it is fully automated and this allows for mass processing of samples, suitable for bigger cord blood banks. For erythrocyte removal, density gradient separation is a better method that is effective. PrepaCyte-CB is the second most efficient method for removing RBC. The result of Total Nucleated Cells (TNC) and Mono Nucleated Cells (MNC) recovery rate of Hespan and Sepax against AXP processing methods shows that both Hespan and Sepax reproducibly recover greater than 95% of the cord blood stem cells in a typical collection and result in a reduced final volume for final storage.
 Conclusion: The five most popular processing techniques are Plasma Depletion, Density Gradient, Hetastarch, PrepaCyte-CB and Automated Centrifugal Machine (Sepax). Most methods involve centrifugation, sedimentation and/or filtration for reducing the red cell content, plasma volume, or both. The different UCB processing methods each has its advantages and disadvantages.

Pore-scale numerical simulation of supercritical CO2-brine two-phase flow based on VOF method

CO2 capture and storage technology is favorable for the reduction of CO2 emissions. In recent years, a great number of research achievements have been obtained on CO2 geological storage from nano scale to oil/gas reservoir scale, but most studies only focus on the flow behaviors in single-dimension porous media. Besides, the physical experiment method is influenced by many uncertain factors and consumes a lot of time and cost. In order to deeply understand the flow behaviors in the process of CO2 geological storage in microscopic view and increase the volume of CO2 geological storage, this paper established 2D and 3D models by using VOF (Volume of Fluid) method which can track the dynamic change of two-phase interface, to numerically simulate supercritical CO2-brine two-phase flow. Then, the distribution characteristics of CO2 clusters and the variation laws of CO2 saturation under different wettability, capillary number and viscosity ratio conditions were compared, and the intrinsic mechanisms of CO2 storage at pore scale were revealed. And the following research results were obtained. First, with the increase of rock wettability to CO2, the sweep range of CO2 enlarged, and the disconnection frequency of CO2 clusters deceased, and thus the volume of CO2 storage increased. Second, with the increase of capillary number, the displacement mode transformed from capillary fingering to stable displacement, and thus the volume of CO2 storage increased. Third, as the viscosity of injected supercritical CO2 gradually approached that of brine, the flow resistance between two-phase fluids decreased, promoting the "lubricating effect". As a result, the flow capacity of CO2 phase was improved, and thus the volume of CO2 storage was increased. Fourth, the influence degrees of wettability, capillary number and viscosity ratio on CO2 saturation were different in multi-dimensional porous media models. In conclusion, the CO2-brine two-phase flow simulation based on VOF method revealed the flow mechanisms in the process of CO2 geological storage at pore scale, which is of guiding significance to the development of CCUS technology and provides theoretical guidance and technical support for the study of CO2 geological storage in a larger scale.

Improving error-correcting capability in DNA digital storage via soft-decision decoding.

Error-correcting codes (ECCs) employed in the state-of-the-art DNA digital storage (DDS) systems suffer from a trade-off between error-correcting capability and the proportion of redundancy. To address this issue, in this study, we introduce soft-decision decoding approach into DDS by proposing a DNA-specific error prediction model and a series of novel strategies. We demonstrate the effectiveness of our approach through a proof-of-concept DDS system based on Reed-Solomon (RS) code, named as Derrick. Derrick shows significant improvement in error-correcting capability without involving additional redundancy in both in vitro and in silico experiments, using various sequencing technologies such as Illumina, PacBio and Oxford Nanopore Technology (ONT). Notably, in vitro experiments using ONT sequencing at a depth of 7× reveal that Derrick, compared with the traditional hard-decision decoding strategy, doubles the error-correcting capability of RS code, decreases the proportion of matrices with decoding-failure by 229-fold, and amplifies the potential maximum storage volume by impressive 32388-fold. Also, Derrick surpasses 'state-of-the-art' DDS systems by comprehensively considering the information density and the minimum sequencing depth required for complete information recovery. Crucially, the soft-decision decoding strategy and key steps of Derrick are generalizable to other ECCs' decoding algorithms.

Numerical study of encapsulated nanoparticles enhanced phase change material in thermal energy cool storage packed bed system

A numerical study is performed to investigate the dynamic behavior of a packed bed containing spherical capsules filled with Al2O3 nanoparticles dispersed in pure water as an enhanced phase change material (NEPCM) that can be utilized in ice storage of air conditioning systems. The heat transfer fluid (coolant) employed in the current work is an aqueous solution of 30 vol% ethylene glycol. For energy conservation of the coolant and the NEPCM, coupled partial differential equations are used to create a two-dimensional axisymmetric time-dependent model. While the energy equation for the NEPCM is solved using a completely explicit scheme, the energy equation for the coolant is discretized using a finite difference method and solved using the Alternating Direction Implicit (ADI) technique. The Al2O3 nanoparticles are dispersed in PCM with a volume concentration range of 0–5 %. The coolant inlet temperature with a range of -5 °C to -15 °C and mass flow rate of range of 0.2 to 0.8 kg/s for a storage volume of 0.5 m3 are the parameters used in the current study. The effect of the nanoparticles volume concentration, coolant mass flow rate, and coolant inlet temperature are investigated. The timewise variation of the solidified volume fraction of the bed, the cool energy stored in the bed, the bed centerline temperature, and the coolant exit temperature are predicted for both charging and recovery modes under different operating conditions.

Challenges to Optimize Charge Trapping Non-Volatile Flash Memory Cells: A Case Study of HfO2/Al2O3 Nanolaminated Stacks.

The requirements for ever-increasing volumes of data storage have urged intensive studies to find feasible means to satisfy them. In the long run, new device concepts and technologies that overcome the limitations of traditional CMOS-based memory cells will be needed and adopted. In the meantime, there are still innovations within the current CMOS technology, which could be implemented to improve the data storage ability of memory cells-e.g., replacement of the current dominant floating gate non-volatile memory (NVM) by a charge trapping memory. The latter offers better operation characteristics, e.g., improved retention and endurance, lower power consumption, higher program/erase (P/E) speed and allows vertical stacking. This work provides an overview of our systematic studies of charge-trapping memory cells with a HfO2/Al2O3-based charge-trapping layer prepared by atomic layer deposition (ALD). The possibility to tailor density, energy, and spatial distributions of charge storage traps by the introduction of Al in HfO2 is demonstrated. The impact of the charge trapping layer composition, annealing process, material and thickness of tunneling oxide on the memory windows, and retention and endurance characteristics of the structures are considered. Challenges to optimizing the composition and technology of charge-trapping memory cells toward meeting the requirements for high density of trapped charge and reliable storage with a negligible loss of charges in the CTF memory cell are discussed. We also outline the perspectives and opportunities for further research and innovations enabled by charge-trapping HfO2/Al2O3-based stacks.

Alleviating Manganese – Vanadium Redox Flow Batteries for Energy Storage and Subsequent Hydrogen Generation

Dual-circuit redox flow batteries (RFBs) consist of two discharging modes which has the potential to store energy beyond the capacity of the electrolytes in the form of hydrogen generation [1-3]. Inspired from the recent exploratory study by Reynard and Girault et al., this work focuses on utilizing Mn3+/Mn2+ (RFB catholyte ~ 1.51 V vs. SHE) in conjunction with V3+/V2+ (RFB anolyte ~ −0.26 V vs. SHE) as indirect redox mediators to drive mediated electrolysis of water in spatially separated external catalytic reactors [3]. The advantage of an additional layer to existing RFB is that a fully charged battery could potentially be chemically discharged particularly when green electricity is available in abundance to provide a secondary resource for energy such as hydrogen gas or other value-added commodity chemicals. However, Mn3+ is prone to rapid chemical disproportionation yielding Mn4+ which precipitates as MnO2(s) particles in acidic media, responsible for severe capacity fade during cycling. Studies in the literature suggest that oxygen scavenging additives such as V5+ is possibly the best defense mechanism to prevent MnO2 formation [4].In this study, the electrochemical behavior of Mn3+/Mn2+ couple in the favorable presence of V5+ is elucidated using cyclic voltammetry and ionic speciation diagrams. The voltammograms obtained under systematically varied conditions provide direct experimental evidence for competing redox reactions at the electrode surface. Nonetheless, the response measured from a macroelectrode mainly describes the quasi reversibility of the redox couple and gives little insight on electrode-electrolyte interface phenomenon. To obtain a more detailed picture of the diffusion layer, we employ carbon disk ultramicroelectrode (UME) for in-depth qualitative analysis. We anticipate that any deviation from the sigmoidal shape is an indication of a growing diffusion layer due to MnO2 passivation on the surface of electrode. Lastly, galvanostatic charge discharge profiles are obtained for Mn-V based redox flow battery with an aim to reveal the optimum state of charge because there exists a trade-off between the extent of Mn disproportionation within RFB during energy storage mode and volume of hydrogen gas produced during secondary mode. The knowledge obtained throughout the study will provide a fundamental understanding required for the rational design and development of aqueous electrochemical flow systems using Mn as the redox active species. Peljo, P., et al., All-vanadium dual circuit redox flow battery for renewable hydrogen generation and desulfurisation. Green Chemistry, 2016. 18(6): p. 1785-1797. Piwek, J., et al., Vanadium-oxygen cell for positive electrolyte discharge in dual-circuit vanadium redox flow battery. Journal of Power Sources, 2019. 439: p. 227075. Reynard, D. and H. Girault, Combined hydrogen production and electricity storage using a vanadium-manganese redox dual-flow battery. Cell Reports Physical Science, 2021: p. 100556. Reynard, D., et al., Vanadium-Manganese Redox Flow Battery: Study of MnIII Disproportionation in the Presence of Other Metallic Ions. Chemistry - A European Journal, 2020. 26.

Precipitation/Dissolution of Supersaturated V(III) Sulfate Electrolytes

Redox flow batteries (RFBs)-based storage systems have the unique feature of separate power generating and energy storage units that can be individually sized. RFBs can be used for days-long energy storage, but because of the low solubility of most ions and molecules in both aqueous and non-aqueous solvents,[1,2] scaling these RFB systems for days-long applications requires significant storage volume and floor area. Our team has been working on a new storage method that significantly increases the energy storage density while still maintaining the traditional flow battery design.[3] This method involves storing the reactants as both soluble ions and an undissolved solid form, only the liquid containing soluble ions is circulated through the batteries. To achieve this, a solid form of Vanadium salt must be precipitated within the storage tanks, necessitating a study on the precipitation and dissolution of various vanadium salts. Past work has been done by our group on the Vanadium (IV/V) solution,[4] we now focus on the Vanadium (II/III) solution. This presentation will discuss the production of Vanadium (III) sulfate salt electrolytes, and the precipitation rate of said salt at oversaturation.

Design and Implementation of Renewable Hydrogen-Based System for Social Housing Decarbonization

The energy transition towards a decarbonized economy requires focused and ambitious policies that must be taken through the agreement of governments, stakeholders, and private companies. The intermittency of renewable energy sources (RES) makes it necessary to implement energy storage systems (ESS) that allow for an uninterrupted supply of low-carbon power. Energy generation and consumption activities are responsible for 75% of global CO2 emissions. Particularly, energy use in commercial and residential buildings is the third major contributor after industry and agricultural activities 1. In this context, hydrogen as an energy vector facilitates and enhances RES penetration in the energy mix. Moreover, it can be employed as a fuel or commodity to obtain other chemical compounds 2. Hence, hybrid renewable hydrogen-based systems (RHS) can play a key role in buildings decarbonization 3. On top of that, green hydrogen may tackle other problems such as energy poverty faced by the most vulnerable and disadvantaged citizens 4.In this context, the SUDOE ENERGY PUSH project proposes an innovative solution for the overall management of social housing located in the regions of southwestern Europe to increase the energy efficiency of public buildings and improve the living standards of vulnerable citizens. Through passive renovation, RES, and BIM methodology, it aims at reducing the consumption and emissions of buildings and at improving the comfort of the inhabitants, overcoming the risks of energy poverty. In this context, a pilot plant combining RES and hydrogen technologies has been implemented in a social housing in Cantabria (Spain) to demonstrate the feasibility and benefits of the system. This demonstration is aimed at achieving energy self-sufficiency of the house throughout the year while saving remarkable amounts of primary energy and CO2 emissions. The primary source of the system will be solar photovoltaic (PV) energy. To combat PV intermittency and harness the periods with energetic surpluses, different energy storage systems (ESS) have been installed within the pilot plant: lithium-ion batteries for short-term energy storage and hydrogen-based technologies for seasonal energy storage. Furthermore, a compressor has been included to reduce the hydrogen storage volume and a programmable logic controller (PLC) rules the operation of the configuration based on the state of charge of the batteries, so that the PLC decides which equipment operates at what time. Finally, the pilot plant is continuously monitored to optimize the control algorithm and enhance the overall performance of the implementation.To carry out the design of the system, an hourly load profile has been built by compiling real consumption data from the smart meter of a home during a year to obtain an accurate hourly load demand. Subsequently, meteorological resources of the location have been considered to obtain an hourly renewable generation profile. Furthermore, equipment costs and characteristics, apart from compressor energy demand have been taken into account. The main objective is to reduce the system size and the resulting levelized cost of energy, as well as increasing the overall efficiency of the system 5.According to the simulated operation of the pilot plant, the home can be disconnected from the grid, saving up to 7,000 kWh per year of primary energy from the grid, 1,000 kg per year of CO2 emissions while consuming 100% clean electricity and more than 600 € per year in electricity bills. As per November 2022, more than 3,500 kWh of primary energy, more than 500 kg of CO2 and more than 400 € have been saved in a six month period, showing a great correlation between the simulation and the real outcomes obtained during the normal functioning of the plant. Acknowledgment This research is being supported by the Project ENERGY PUSH SOE3/P3/E0865, which is co-financed by the European Regional Development Fund (ERPF) in the framework of the INTERREG SUDOE program, as well as the project, “HYLANTIC”-EAPA_204/2016 within the framework of the INTERREG ATLANTIC program. Furthermore, the Spanish Ministry of Science, Innovation, and Universities is also supporting this investigation through the projects PID2021-123120OB-I00, TED2021-129951B-C21 and PLEC2021- 007718 References 1 H. Ritchie and M. Roser, CO₂ and Greenhouse Gas Emissions, https://ourworldindata.org/co2-and-other-greenhouse-gas-emissions.2 I. Staffell, et al., Energy Environ. Sci., 2019, 12, 463–491.3 V. M. Maestre, A. Ortiz and I. Ortiz, Renew. Sustain. Energy Rev., 2021, 152, 111628.4 V. M. Maestre, A. Ortiz and I. Ortiz, J. Chem. Technol. Biotechnol., 2022, 97, 561–574.5 V. M. Maestre, A. Ortiz and I. Ortiz, J. Energy Storage, 2022, 56, 105889. Figure 1

A residual oil zone (ROZ) assessment methodology with application to the central basin platform (Permian Basin, USA) for enhanced oil recovery (EOR) and long-term geologic CO2 storage

Residual oil zones (ROZ) form due to various geologic conditions and are located below the oil/water contact (OWC) of main pay zones (MPZ). Since ROZs usually contain immobile oil, they have not typically been considered commercially attractive for development by conventional primary recovery methods used in the initial phases of oil production. However, during the last decade some operators of these viable fields that also contain ROZs have extended carbon dioxide enhanced oil recovery (CO2-EOR) to below the MPZ to commercially recover oil from the associated ROZ. Increased interest in ROZs is also due to the application of anthropogenic CO2 for oil recovery, leading to the subsurface sequestration of CO2, which can be part of the current net-zero carbon oil and climate change objectives.Several detailed studies of selected formations in the Permian Basin of the United States have shown that ROZs can be as common as traditional conventional oil reservoir traps, suggesting significant resources for potential additional hydrocarbon recovery and subsurface CO2 sequestration via CO2-EOR. However, applications of CO2-EOR to ROZs have been limited despite the estimation of significant oil resources considered recoverable through CO2-EOR, and the benefit of concurrent geologic CO2 storage that would help offset carbon emissions from the produced oil. The combination of insufficient economic incentives and technical reasons related to data scarcity, such as lack of penetration of wells and well logs, for locating ROZs has limited development of their resource potential when compared to known fields.This paper presents a probabilistic methodology for identifying and evaluating ROZ resources for CO2-EOR and CO2 sequestration potential with the use of public and proprietary data sources. The methodology was developed during a pilot study that focused on the ROZ in the San Andres Formation of a nine-county area in the Permian Basin in West Texas. The pilot study estimated a mean oil in place of 25 × 109 barrels (bbl) of oil and a mean potential incremental oil recovery and CO2 utilization of 2.6 × 109 bbl and 28.2 Tcf (1.46 × 109 tons), respectively, with 1 hydrocarbon pore volume (HCPV) of injection using the water alternating gas (WAG) method. The results of this pilot study are consistent with reported volumes in the literature for a similar area in the Permian Basin. The pilot study demonstrated that this methodology could be used to identify and assess the recoverable oil and coincident CO2 storage volumes of ROZs in other formations and regions.

Stormwater Tree Pits for Decentralized Retention of Heavy Rainfall

Stormwater tree pits with storage elements enable the irrigation of urban trees and can potentially act as decentralized rainwater retention basins. This paper mainly focuses on analyzing this potential. Field tests were conducted to investigate the irrigation behavior and the storage effect of a storm water tree pit system using Perl hoses as irrigation elements over a period of two years. The rainfall, storage volumes, and soil moisture within the employed planting pit were measured. With the help of system modeling, the retention ability of the storm water tree pit system was analyzed. The available storage volume was sufficient to irrigate trees for several days. During the measurement period, about 15% of the inflowing rainwater was fed to the root zone of the tree. With practical storage volumes of 200 to 300 m3/ha, a remarkable amount of water from heavy rainfall could be completely stored, thus significantly reducing the risk of flooding. The retention effect and irrigation behavior largely depend on the soil conditions and the technical possibilities of the equipment supplying the root area (in this case, Perl hoses). Further investigations are required to determine the influence on the growth conditions of trees and optimize of the system for discharge into the root zone.

Photovoltaic thermoelectric cooling system for off-grid vaccine refrigerator: an experimental study

The rapidly rising demand for refrigeration technologies, mainly in refrigeration and air conditioning, medical applications, and electronic component cooling, produced much more energy than required. Thermoelectric refrigeration is an innovative way to use additional energy to cool and reserve cooling. In this research, a photovoltaic-thermoelectric refrigeration system capable of sustaining vaccine storage within the limit of 2–8 °C has been established by experimentally optimizing its volume and performance. The design specification is to cool the volume using forced convection to the desired temperature range in less than 30 min and sustain retained heat for at least the next hour. The experimental research is divided into two stages: the first determines the optimal volume of vaccine storage under different testing conditions using only grid power, and the second analyses storage performance using solar energy through photo voltaic (PV) integration. The solar direct drive and the solar drive with battery support have been timed, revealing a holding period of 4 h, 46 min and 5 h, 29 min, respectively. The refrigerator's design criteria, prospective characteristics, and final design are all thoroughly highlighted. Finally, we conclude that this research will likely benefit the modeling and analysis of thermoelectric cooling systems.

Experimental and numerical study on the two-phase flow inside a cracked gas diffusion layer of PEMFC

The presence of cracks in the gas diffusion layer (GDL) can have a significant impact on the flow of two phases within Proton Exchange Membrane Fuel Cells (PEMFCs). This study focuses on investigating the transport process of two-phases flow in a GDL sample using both experimental and numerical methods. The porous structure of a hydrophobic carbon paper, serving as the macro-porous substrate (MPS) of the GDL, is examined using synchrotron radiation X-ray phase contrast Computed Tomography (CT). A 3-D model with various crack geometries is then created, and a Lattice Boltzmann Method (LBM) simulation is employed to analyze the flow behavior within the GDL model. The findings reveal that the water intrusion mode in the MPS primarily depends on its hydrophobic nature, but the width and depth of the cracks also significantly influence both the rate and path of water intrusion. Increasing the crack width from 7 μm to 28 μm results in a 30% increment in water intrusion rate, while the intrusion path remains unchanged. However, when the crack width reaches 42 μm, the crack itself becomes the primary path for water intrusion, doubling the intrusion rate. Furthermore, an increase in crack depth leads to a higher invasion rate of the liquid phase, consequently increasing the liquid storage volume within the GDL. This research provides a novel approach for analyzing cracked GDLs and demonstrates the potential to optimize the water management process of PEMFCs through GDL microstructure design.