Tank Size Research Articles

Redox cycle of calcium manganite for high temperature solar thermochemical storage systems

Thermochemical energy storage via metal oxide redox cycling is a potential cost-effective approach to store solar energy both chemically and thermally at high temperatures, enabling efficient solar thermal power production round-the-clock and on-demand. Perovskite manganites are a low-cost redox material that undergoes reversible reaction without side reactions up to 1000 °C and offers high storage capacities, which makes them promising energy storage materials in next-generation solar thermal power plants. In this study, the thermal properties of a typical perovskite manganite, CaMnO3, has been studied. CaMnO3 shows 893.2 kJ/kg energy storage capacity from 200 °C to 1000 °C, and 0.133 non-stoichiometry in N2. The material exhibits excellent stability with 150 redox cycles between 500 °C and 1000 °C. The thermodynamic efficiencies of two solar-driven combined cycle power systems with CaMnO3 based thermochemical energy storage system are also investigated. The steady-state mass and energy conservation equations are solved for all system components to calculate the thermodynamic properties and mass flow rates at all state points in the system. Preliminary results for a system with 120 MW nominal solar power input at a solar concentration ratio of 1000 are presented, designed for constant round-the-clock operation with 9 h of on-sun and 15 h of off-sun operation. The CaMnO3 particles store and release energy via the sensible heat and reaction heat, yield a net power block efficiency of approximately 60% and an overall energy conversion efficiency of up to 48.7%. Required storage tank sizes for the solids are estimated to be up to 2–3 smaller than those of state-of-the-art molten salt systems.

A Case Study on Reliability, Water Demand and Economic Analysis of Rainwater Harvesting in Australian Capital Cities

This paper presents reliability, water demand and economic analysis of rainwater harvesting (RWH) systems for eight Australian capital cities (Adelaide, Brisbane, Canberra, Darwin, Hobart, Melbourne, Perth and Sydney). A Python-based tool is developed based on a daily water balance modelling approach, which uses input data such as daily rainfall, roof area, overflow losses, daily water demand and first flush. Ten different tank volumes are considered (1, 3, 5, 10, 15, 20, 30, 50, 75 and 100 m3). It is found that for a large roof area and tank size, the reliability of RWH systems for toilet and laundry use is high, in the range of 80–100%. However, the reliability for irrigation use is highly variable across all the locations. For combined use, Adelaide shows the smallest reliability (38–49%), while Hobart demonstrates the highest reliability (61–77%). Furthermore, economic analysis demonstrates that in a few cases, benefit–cost ratio values greater than one can be achieved for the RWH systems. The findings of this study will help the Australian Federal Government to enhance RWH policy, programs and subsidy levels considering climate-sensitive inputs in the respective cities.

Optimization of pipeline lifecycle cost using alternatives with different life spans

Abstract This paper suggests a pipeline project optimization approach that compares alternatives with different life spans. The average inflation rate is used to project the future maintenance, operation and replacement costs. The average interest rate is used to express all the costs in Equivalent Real Annual Cost (ERAC), which is the correct cost form to compare alternatives with different life spans. The pipe diameter, material, pressure rating, surge tank size, and inlet/outlet resistances are the decision variables. A software was compiled with a commercial pipeline software to generate all the possible design alternatives based on the decision variables. Pipe initial cost as well as operation and maintenance costs are computed for each design alternative. The alternative with the least ERAC value is the optimum one. It was found that the approach can lead to substantial savings in pipeline projects cost. For pipes 800 mm in diameter or larger, and when selecting the optimum diameter, savings are between 23 and 27% in the total project cost. When imposing certain pipe material savings in overall cost will be 8.5, 16.3 and 31.3% for ductile iron, GRP and mild steel pipe material, respectively.

Reliability Analysis of Rainwater Harvesting Tanks for Irrigation Use in Greenhouse Agriculture

Rainwater harvesting is an ancient water management practice that has been used to cover potable and non-potable water needs. In recent years, this practice is adopted as a promising alternative and sustainable source of water to meet irrigation needs in agriculture in arid and semi-arid regions. In the present study, a daily water balance model was applied to investigate the size of rainwater tanks for irrigation use in greenhouse begonia and tomato cultivation in two regions of Greece with significant greenhouse areas. For the application of the water balance model, daily rainfall depth values of a 12-year time series (2008–2020) from representative rainfall stations of the study areas were used, as well as the daily water needs of the crops. The greenhouse roof was assumed to be the water collection area of the rainwater harvesting system with values ranging from 1000 to 10,000 m2. The analysis of the results showed that in the case of the begonia crop, the covered tanks ranged from 100 to 200 m3 per 1000 m2 greenhouse area with a reliability coefficient that ranged from 65 to 72%, respectively, to meet the water needs of plants. Further increase of the reliability coefficient was carried out with disproportionately large volumes of tanks. In the case of the tomato crop, covered tank volumes ranged from 100 to 290 m3 per 1000 m2 of greenhouse area, and had a reliability coefficient of 90% to 100%, respectively, while uncovered tanks had a maximum reliability coefficient of 91% for a critical tank volume of 177 m3 per 1000 m2 of greenhouse area and decreased for any further increase of tank volume.

Comprehensive optimization of project cost for long supply pipelines

This paper proposes a “comprehensive” pipeline design optimization approach that considers pipe parameters, protection device parameters, and project maintenance and operational costs over the pipeline’s service life. The objective is to search for an optimal pipeline design by analyzing alternatives with different lifespans, while taking inflation and interest rates into account. A specially designed genetic algorithm routine suggests possible solutions that encompass a range of available pipe diameters, pipe materials, pipe pressure ratings, surge tank sizes, and inlet/ outlet resistances. With both steady-state and unsteady pipe flow analyses, the solution provides a system satisfying required demand without violating velocity and pressure constraints. A real-world project is selected to investigate the outcome of the optimization procedure. The proposed comprehensive optimization approach is shown to be an effective method of comparing a wide range of design alternatives for pipeline projects and identifying the one that optimizes the overall cost.

Water Supply Reliability of a Joint Rainwater Storage and On-Stream Reservoir System

Rainwater is regarded as an alternative water source for water supply augmentation in metropolitan areas to mitigate rising water stress caused by increasing population and climate change. There exists a knowledge gap in the evaluation of rainwater-harvesting systems to increase urban water supply reliability. This study provides insight into the impacts of developing rainwater-harvesting systems to improve urban water supply reliability by modeling joint water supplies from both decentralized rainwater-harvesting systems and centralized stream reservoirs. The model is then applied to Melbourne, Australia, using two rainfall regimes. The results show that enlarging roof areas and rainwater tanks, especially for new homes, can increase volumetric rainwater supply reliability at the household scale. This not only increases supply for households but also increases water supply reliability of stream reservoirs at the regional scale. An average roof area of 200 m2 and an average tank size of 8–10 KL can harvest enough rainwater in Melbourne to increase reservoir water supply reliability to 90% for current urban water demand during an extended drought. Using these results, efficient sizes for rainwater tanks are determined by analyzing the cost of enlarging a tank compared with its marginal benefit of increasing rainwater supply reliability. Furthermore, the impacts of climate variability and demand seasonality on system performance are explored using storage-reliability-yield curves for rainwater-harvesting systems. These results provide general insights regarding the feasibility of rainwater water supply augmentation constrained by tank size, roof area, rainfall regime, and demand seasonality. The proposed method for coupling a rainwater tank model at the household scale with a reservoir model at the regional scale is transferable to the design of regional rainwater-harvesting strategies in other cities.

How do sparkling wine producers adopt a sub-appellation? Evidence from an exploratory study on heroic Prosecco Superiore Rive

This paper investigates why wineries producing Conegliano Valdobbiadene Prosecco Protected Denomination of Origin (CVPP) wines decided to adopt the sub-appellation (SA) “Rive” as a way to increase the value of their wines.
 We estimated both a logistic and a linear regression to explain Rive SA firms’ choices and market growth drivers, respectively. By using data gathered from CVPP producers, we divided wineries into two groups, those that have adopted the Rive SA and those that have not. By means of a stepwise procedure, we categorized factors that were likely to explain the Rive SA choice within a set of structural, marketing and wine tourism-related variables.
 The results showed that structural drivers such as the human capital of younger producers, pressure tank sizes, competitive positioning in the market and in the field of wine tourism hospitality, and involvement in ad hoc promotional activities (i.e., Primavera del Prosecco) have the greatest effects on the choice of the Rive SA. The synergistic effects of cellar door sales, small firm sizes and specific foreign markets (i.e., the United Kingdom and the United States) have emerged, on the other hand, as vital factors in the growth of the Rive SA in terms of market share.
 The adoption of the Rive SA may play an important role in supporting and valuing the heroic viticulture-based economy and may help the CVPP Tutelary Consortium to appropriately undertake promotional strategies to differentiate wines and improve competitiveness. This could have positive effects on wine tourism, hospitality and winery visits in light of the recent recognition of the CVPP as the 55th Italian UNESCO World Heritage site.

Stability analysis of the thermocline thermal energy storage system during high flow rates for solar process heating applications

The thermal energy storage system is a pivotal system for solar thermal plants for improving reliability. The stability in the thermocline is more significant to clarify and improve the performance of thermal energy storage tank which legitimately shows the quality of the thermocline. In this stability analysis investigation, the modern engineering energy storage material concrete was used as a filler material for high-temperature thermal energy storage applications as a result of the intrinsic properties. A comprehensive laminar and k-ε turbulent flow energy transport model accounts for the heat transfer fluid and filler material with adiabatic and non-adiabatic conditions using LTNE (Local Thermal Non-Equilibrium model). The axial, radial, and diagonal temperature differences were identified which was used to calculate the stability of the thermocline. A thermal energy storage tank size of 1 m height and 0.250 m diameter with a 0.030 m size of filler material packed with an average porosity of 0.3 for the storage capacity of 150 kWh/m3 is used for solar process heating applications considered for the present study. The thermocline stabilities are performed with Reynolds numbers, Re varied from 1 to 3000. It is found that the Re = 1 provides better stability in the axial and radial direction as well as diagonal than other Reynolds number. It is observed that Re = 1 provides superior discharging efficiency for nearly 5.84 hrs which is highly suitable for solar process heating applications and the discharging efficiency consistently drops, when Re increases from 1 to 3000. The wall condition of the tank and velocity of the heat transfer fluid is highly disturbing the thermocline in the radial direction and it creates a ‘spike’ profile in the axial direction. Based on the newly introduced stability scale, the effective length of packing and timing to achieve stability is identified for H/D = 4. From that result, the top and bottom layer of the thermocline tank porosity is also found which is used to decide the porosity of the packed bed distributors. The identified porosity for the top and bottom distributors in the ɛ = 0.3 thermal energy storage tank is less than 0.3 is more suitable for provide the uniform flow in the tank.

Planning level sizing of heat pumps and hot water tanks incorporating model predictive control and future electricity tariffs

Heat pumps and hot water tanks in local energy systems require sizing to increase on-site renewables self-consumption; decrease costs through variable electricity pricing; and utilise low-cost wind power. While detailed tools can capture these mechanisms, planning-level tools lack functionality and miss these benefits. In this paper an open-source planning-level modelling tool, PyLESA, is presented and applied to a sizing study to demonstrate the capturing of these benefits at the planning-level. Specific aims of the study were to investigate: (i) model predictive control vs. fixed order control, (ii) existing and future wind-influenced electricity tariffs, and (iii) optimal cost size combinations of heat pump and hot water tank. The lowest levelized cost of heat for the existing tariffs was for a time-of-use tariff, 750 kW heat pump and 500 m3 hot water tank combination. For the future wind-influenced tariff a 1000 kW heat pump and 2000 m3 hot water tank was cost optimal and showed model predictive control benefits over fixed order control with levelized heat costs reducing 41 %, and heat demand met by renewables increasing 18 %. These results demonstrate PyLESA as capable of capturing flexibility benefits at the planning stage of design and quantify the advantage of combining flexible tariffs with model predictive control.

Design Criteria Assessment for the Aeration Tank in the Activated Sludge Process. (Dept. C)

In Egypt, the use of activated sludge process for treating domestic wastewater has been started recently. Several of activated sludge plants have been constructed in cities and villages. The kinetic coefficients used in sizing of the aeration tanks for these plants were taken the same as in the developed countries although the climatic conditions, load variation, presence of industrial wastewater and wastewater characteristics in Egypt differ than that in developed countries. A continuous flow activated sludge pilot plant was operated in El-Mansoura university sanitary engineering laboratory to determine the kinetic coefficients for El-Mansoura city and Meet-Mazah village wastewater. The results indicated that the aeration tank design volume greatly influenced by wastewater kinetic coefficients and model used in the design. The aeration tank design volumes according to Lawrence and mccartys model and Kincannon and Stover model are almost equal. On the other hand the design volumes according to Eckenfelder model Eckenfelder modified model are very high compared to other models. In all cases, it is recommended to run a pilot plant to determine the wastewater kinetics for accurate sizing of aeration tanks.

Dynamic modeling and thermal management of a Power-to-Power system with hydrogen storage in microporous adsorbent materials

The increasing penetration of distributed renewable energy sources involves the development of efficient energy storage solutions. Hydrogen is a viable alternative, or complement, to electric batteries for long-term and high-capacity storage. This article assesses the benefits of hydrogen storage in microporous adsorption materials at room temperature. The integrated Power-to-Power system dynamic behavior is modelled. We assessed the system performance looking at hydrogen adsorption in four porous materials (MSC-30, IRMOF-1, NU-110, and C/Be2) at room temperature for high-storage capacity. Hydrogen storage in an empty pressurized vessel by means of mechanical compression only is evaluated for comparison of the previous cases. The best performance in terms of tank volume size and round-trip efficiency are obtained by adopting adsorbent materials as follows: C/Be2 > IRMOF-1 > NU-110 > MSC-30 > empty storage. Indeed, under the same operating conditions, the volume size of the storage tank is reduced by 38 to 88% compared to the empty vessel, and the round-trip efficiency gain ranges between 0.6 and 2.8 percentage points according to the properties of the adsorbent material. Finally, by filling the storage tank with adsorbent materials the DOE targets are met at a pressure from 45% (MSC-30) to 83% (C/Be2) lower than in an empty tank.

Multi-Objective Model-Based Assessment of Green-Grey Infrastructures for Urban Flood Mitigation

This paper presents the performance quantification of different green-grey infrastructures, including rainfall-runoff and infiltration processes, on the overland flow and its connection with a sewer system. The present study suggests three main components to form the structure of the proposed model-based assessment. The first two components provide the optimal number of green infrastructure (GI) practices allocated in an urban catchment and optimal grey infrastructures, such as pipe and storage tank sizing. The third component evaluates selected combined green-grey infrastructures based on rainfall-runoff and infiltration computation in a 2D model domain. This framework was applied in an urban catchment in Dhaka City (Bangladesh) where different green-grey infrastructures were evaluated in relation to flood damage and investment costs. These practices implemented separately have an impact on the reduction of damage and investment costs. However, their combination has been shown to be the best action to follow. Finally, it was proved that including rainfall-runoff and infiltration processes, along with the representation of GI within a 2D model domain, enhances the analysis of the optimal combination of infrastructures, which in turn allows the drainage system to be assessed holistically.

Numerical study of the liquid sloshing in the cylindrical tank with baffles

Many kinds of dangerous chemicals, like liquefied natural gas etc., are stored or transported in liquid state by pressure vessel. Liquid sloshing will occur in many scenarios such as during the geological disasters, and the transit operations. Sloshing might lead to large deformation or even damage to containers, causing serious safety threats. In this study, the sloshing phenomenon in a cylindrical tank with four baffle shapes are investigated. The volume-of-fluid (VOF) method is used to track the distorted and broken free surface. Fluid movement phenomenon in tank with different baffles is observed. The effect of four different baffles shapes is compared, impacting force on tank and baffle walls which induced by liquid sloshing is analyzed. Baffles openings affect the impact forces on the tank and baffle walls. More number of baffle orifices, liquid distribution is more even in sections of the tank. Maximum force value of y direction occurs as the liquid climbs up the tank ceiling. Reasonable number and position of baffle openings can increase the stability of the tank during driving. For this simulation method, more validation with experimental data is necessary, the same size of tank and four baffle shapes will be tested on the shaking platform.

Design Enhancement of Forced Circulation Solar Water Heater for Residential Buildings in Saudi Arabia

This study presents a proposed configuration of an innovative residential Solar Water Heater (SWH) system that will meet the hot water requirement and achieve a lower payback period in Saudi Arabia. Different SWH configurations were evaluated in terms of collector type, circulation method, heat exchanging mechanism and hot water storage. Also; the effect of SWH variable parameters on its thermal performance were determined. The variable parameters included collector tilt and orientation angles, albedo ratio, circulation flow rate, tank size, heat exchanger effectiveness and customer hot water supply temperature. The study covered five different cities, which represent different climate conditions. Proper optimization of SWH system configuration resulted in 30% reduction in the system payback period, which is about 4.3 years. Better economic figures can be expected for the installation of SWH systems in commercial and industrial sectors. Keywords: Solar water heating, System Advisor Model, SAM, Saudi Arab DOI: 10.7176/JETP/11-4-02 Publication date: July 31 st 2021

Moving and Fixed Biological Biofilm Systems in Wastewater Treatmentwhen dose an Application Makes Sense

This study demonstrates the optimization of different Biofilm applications in wastewater treatment for a cost-effective solution. The increase of wastewater treatment cost because of high treatment efficiency requested and energy consumption makes such applications very interested in this field. Therefore, aerated reactors for wastewater treatment units were designed to work as Submerged Fixed Biofilm Bed, on the basis of biofilm-microorganisms attached to monolithic plastic supports to increase the treatment efficiency. This application depends on the aerobic process and achieved by the aeration in BOD reduction and Nitrifications reactors (Oxidation of organic compounds and nitrification). This was implemented by mixing and transport treatment processes within the biofilm attached to the plastic fixed media. The anaerobic reactor in this study was designed also to be simultaneous the de-nitrification stage by the application of a moving bed de-nitrification reactor which was considered as a part of the wastewater treatment process to achieve high treatment efficiency for the study pilot plant. The one-year-scientific evaluation was conducted onsite for the municipal wastewater pilot plant includes a test series with well-defined treatment parameters (soft mixing of the suspending the moving bed carriers; intermediate solids removal unit prior to the nitrification reactors; the mechanism for preventing the carriers to move with the flow into the subsequent reactor) such as waste-water-flow, quality, temperature, salinity, organic and hydraulic load and extensive sampling). The above application of the compact-container-system is considered as a typical field of application, for the following reasons: Need of quality improvements discharged into water body, which is often in the vicinity of bathing beaches; Need for Nutrient-Removal-Systems to avoid algae growth going into water bodies and; Space limitations in a resort and saving the implementation capital cost). The comparison between the application of the biofilm concept and the activated sludge system saved more than 40% tank size; 85% space/area; and up to 30% construction cost.

Non-Linear Time History Analysis of an Elevated Water Tank

It was discovered that reinforced concrete elevated water tanks with frame staging outperformed reinforced concrete elevated water tanks with shaft staging in terms of seismic resistance. These can be due to the frame staging's seismic energy absorption capability. As a result, the primary goal of this research is to better understand the seismic behavior and performance characteristics of elevated water tanks with frame staging. Furthermore, when compared to other shapes, circular tanks have the smallest surface area for a given tank size. As a result, the amount of material needed for a circular water tank is less than for other shapes. As a result, a circular water tank was chosen, and seismic analysis of elevated RC circular water tanks was carried out according to IITK-GSDMA guidelines, with the behavior of the water tank analysed for various parameters such as zone factor, soil condition, and different staging heights. SAP 2000 was used to determine the structure's modal characteristics (mode shapes and modal participation mass ratio).

Equilibrium Theory Analysis of Pressure Equalization Steps in Pressure Swing Adsorption

A binary, linear isotherm, isothermal equilibrium theory analysis of Skarstrom-type PSA cycles with bed-to-bed (BB) and bed-to-tank-to-bed (BTB) equalization steps was carried out with a binary gas mixture of A and B, with A more strongly adsorbed than B. For tractability, it was assumed that the gas produced from the light end of a bed contained only B and thus the recovery of A in the heavy product was 100%. Analytic expressions for the periodic state PSA cycle performances based on the recovery of B in the light product ReLP,B, the purity of A in the heavy product y̅HP, and the final pressures of the BB and BTB equalization steps were derived. The effects of the relative size of the equalization tanks Ψ (varied from 0.1 to 500) and the number of equalization steps n (varied from 1 to 10) were studied. The initial pressure in the bed at the beginning of the countercurrent depressurization (CnD) step ΠCnD,o was important. With increasing Ψ or n, ΠCnD,o always decreased and both y̅HP and ReLP,B always increased, and when the BTB and BB configurations achieved the same ΠCnD,o, their PSA cycle performances were identical. Increasing Ψ at constant n caused the BTB ΠCnD,o to approach that of the BB ΠCnD,o, and they became equal for only very large tanks (e.g., Ψ = 500). However, increasing nBTB at constant nBB and Ψ caused the BTB ΠCnD,o to be even lower than the BB ΠCnD,o for some reasonable Ψ. Therefore, instead of using larger tanks in BTB to achieve the same BB performance, it was better to increase nBTB at a reasonable Ψ to keep the tank volume smaller. For the same performance (i.e., the same ΠCnD,o), the total volume of all tanks (i.e., nΨ) decreased with increasing n, and in the limit of nBTB → ∞, nΨ approached a minimum total tank volume equal to nBB. This result indicated a lower limit exists on the minimum total volume of tanks required to achieve the same performance as in the BB configuration.

Estimating Body Conductivity and Immobilization Threshold in Fish

AbstractThe body conductivity of fish (Cf; µS/cm) and the power density causing threshold immobilization (Dm; µW/cm3) play a critical role in determining electrofishing success. My aim was to compare two methods for estimating Cf and Dm: the response‐threshold method using live Rainbow Trout Oncorhynchus mykiss (12–15 cm TL) and the direct‐measure method using the carcasses of the same fish. The estimates were compared to values from other published studies. I also evaluated the effect of electric field constriction (e.g., depth effect) on Cf and Dm in tanks with water : fish cross‐sectional area ratios of 6:1, 25:1, and 100:1. The resulting data conformed to theory for both methods; that is, Cf and Dm increased with decreasing tank size because field constriction forced more electric current through a fish. Estimates of Cf and Dm by both methods were similar in the two larger tanks (25:1 and 100:1). I suggest a standard Cf value of 60 µS/cm for Rainbow Trout if they are the target species. This value is near the low end of a cluster of published values for various fishes (50–160 µS/cm) that are within cross‐sectional ratios of 20:1 to 100:1. A standard value for Dm cannot be recommended due to variation caused by electrical output and fish size and species. The direct‐measure method proved superior to the response‐threshold method because it requires fewer fish for estimates of Cf and Dm, does not depend on subjective determination of threshold in live fish, and provides information on water‐to‐fish power transfer efficiency.

Elevated tanks effect on transient pressures: case study

Abstract Elevated tanks are an integral part of the water supply networks. This paper highlights the effect of elevated tanks' location and size on the transient pressures resulting from the sudden failure of pumps. A comparison between the impact of elevated tanks and air vessels on the water hammer was also performed. The Bentley HAMMER model was first validated then applied to analyze the unsteady flow within an actual distribution network. The results display that the elevated tanks have a considerable effect on the surge pressures, where they improve the extreme pressures effectively at and around them, but they cannot fully protect the system from the water hammer risks, as there are still relatively large negative pressures at some distant junctions. Besides, as the tank capacity increases, the surge pressures increase slightly. In our case study, the best location of the elevated tank is at the network extremity and then at the pumping stations, since the minimum pressures improve by 67 and 54%, respectively. Although the present case study may differ from other supply systems, the obtained results can provide an indication of the elevated tanks' role in alleviating undesirable water hammer effects.

Chlorine Decay Simulation in Water Distribution System Using EPANET

Chlorine is used as a disinfectant in the water treatment process so that treated water is delivered safely to consumers. However, chlorine concentration decays when water flows from the treatment plant to the supply point, due to the reaction with natural organic matter and the inner surface of the pipe. Low chlorine concentration may encourage bacteria re-growth, while high chlorine concentration can result in the formation of harmful chemical components. Therefore, this study aims to simulate the complex process of chlorine decay using EPANET. This exercise enables the determination the chlorine concentration dosage required to maintain the desired requirement given by the World Health Organization (WHO) and the Ministry of Health, Malaysia (MOH). A successful model with an extended period of simulations of 72 hours enable the mapping of spatial and temporal variations of flow and residue chlorine concentrations at all links and nodes. Constant chlorine dosage of 3.96 mg/l at node R1 has successfully satisfy the requirement given by WHO and MOH. The residue chlorine concentrations at the nodes and links in the water distribution system also depends on the water usage at node 5, the size of service reservoir and service tank and distance from the reservoir.