Tank Capacity Research Articles

A hybrid variable neighborhood search for a real-world petrol station replenishment problem with multi-compartment vehicles

Studies on the Petrol Station Replenishment Problem (PSRP) have many challenges because of the limitations in real-world PSRP, including diverse oil products, various vehicle models, multiple compartments in each vehicle, a finite set of vehicles, restricted tank capacities of petrol stations, and the preparation time and cost for discharge. To address those problems, this paper proposes a novel PSRP model considering the following realistic scenarios: each vehicle has multiple compartments and is allowed for multiple trips; vehicles are heterogeneous; petrol stations have hard time windows; external vehicles can be rented when internal vehicles are not enough; after arrival, each vehicle must prepare for a certain time before discharge. The objective is to minimize the overall costs including vehicles’ fixed costs, traveling costs, and preparation costs. A Hybrid Variable Neighborhood Search algorithm (HVNS) combined with a Simulated Annealing-based acceptance criterion is developed to solve the problem. Various experiments are conducted on different scale instances and a practical application of PetroChina. Experimental results show that compared with CPLEX and other heuristics, HVNS can effectively solve the problem in terms of solution quality and computing time.

Assessment of the lost cargo capacities of a container vessel when transitioning to alternative fuels

Abstract: Alternative fuels represent a viable solution to the decarbonization of the maritime industry. There are several options available with some technologies mature and ready to use. Other technologies are still under development; however, it is a certainty that alternative fuels and newer technologies could substitute conventional fuels. Changing to alternative fuels comes with a price. For cargo vessels, it is the loss of cargo space, due to the higher energy density of alternative fuels compared to fossil fuels. The present study calculates the cost of lost cargo when an 8000 TEU container vessel is burning methanol and ammonia. It is noted that additional cargo space required for methanol is 1674 m3, while for ammonia is 2277 m3. The cargo lost space has a significant impact on the earning potential of the vessel throughout its lifetime. Regardless of whether the owners choose a one-stop or two-stop approach, the owners must determine the frequency of bunkering based on the vessel's route and conduct a thorough review of the fuel tank capacity.

Improving Crude Oil Tank Inventory Stock Availability Through Compact Solution Method to Ensure National Fuel Supply Security at PT Kilang Pertamina International Unit VI Balongan

PT Pertamina International Refinery Unit VI Balongan plays a crucial role in maintaining national fuel oil (BBM) and special fuel (BBK) supply resilience. However, challenges such as declining crude oil storage capacity due to tank damage and limited space threaten the continuity of refinery operations and the stability of national energy supply. This study aims to address this issue by implementing the compact solution method to enhance crude oil stock availability and secure the national fuel supply. Using a quantitative approach with descriptive methods, the research collected data through observation, document review, and literature study. The data were analyzed qualitatively to assess the impact of the compact solution method. The results indicate a significant improvement in crude oil stock availability, which increased from 60.14% (using the off-stream repair method) to 72.9%. Additionally, the tank level was successfully increased to a maximum of 13,990 mm, adhering to API 650 or API 579 FFS Level 3 standards. This improvement extends the operational lifespan of the tank to 62 years, reducing maintenance costs and ensuring uninterrupted refinery operations. The findings highlight the effectiveness of the compact solution method in addressing crude oil tank capacity issues and securing national energy resilience. These results provide valuable insights for energy sector stakeholders in optimizing crude oil storage and refinery operations while minimizing repair costs and downtime.

The green marine waste collector routing optimization with puma selectison-based neighborhood search algorithm

AbstractImproper waste disposal by humans has created significant environmental issues in the marine ecosystem, including endangering aquatic life and accelerating the extinction of certain marine species. Due to the floating nature of the marine debris, the coordinates for collecting activities must be estimated in advance. In this article, GNOME software is used to estimate the coordinates of debris, and then a fleet of several ships is used to collect them. Also, a mixed integer linear programming model is presented for the routing optimization of debris collection fleets. The proposed optimization model formulates the objective function based on numerous factors, including labor cost, rent, and ship insurance, and considers constraints on fuel tank capacity, the time window, and the ship’s cargo capacity. A new hybrid algorithm combining the Puma algorithm and neighborhood search is proposed to address the problem. Metropolis acceptance is used in the simulated annealing algorithm to avoid the local optima and greedy selection. Numerical examples of the marine survey and the port of Rotterdam are used to test the proposed approach, which has been proven effective in several scenarios. Results achieved from the proposed hybrid method demonstrate considerable performance improvement in solving the problem. This approach has decreased total fuel and labor costs by 10–15% compared to conventional methods, with minimized time window violation reaching 25%. These results show a significant reduction in total operational costs with proper scheduling and route planning.

Vertical stratification of the water microbiome in an electric water heater tank: implications for premise plumbing opportunistic pathogens.

Hot water systems are the most frequent environment associated with the prevalence and growth of opportunistic premise plumbing pathogens (OPPPs). Previous studies identified water heaters as a source of waterborne diseases and concluded that design variables may contribute to their prevalence. A multifaceted approach was used to investigate the vertical stratification of the microbiome and selected OPPPs in an electric water heater tank connected to a home plumbing system simulator. Results show that the microbiome is highly diverse with evidence of temperature stratification and temporal structuring influenced by the partial drainage of the tank. Representatives of the Mycobacterium spp. were the most prevalent taxa, followed by Legionella spp., and a relatively low prevalence of free-living amoeba Vermamoeba vermiformis. Higher concentrations of Legionella pneumophila at the bottom of the tank indicated the potential growth and protection of this opportunistic pathogen at this location. Overall, partial drainage of the water tank (60% of the tank capacity) did not significantly mitigate the microbiome and selected OPPPs. The outcome of this study sheds light on the role of vertical stratification on water quality and demonstrates the resilience of the microbial community residing in an electric water heater tank and the implications for public health.

Design of a hybrid solar and biomass-based energy system integrated with near-zero energy building: Techno-environment investigation and multicriteria optimization

The current research aims to meet the energy needs of a group of residential buildings in Norway with the least amount of carbon dioxide emission and the greatest amount of renewable energy. The supply side based on the renewable renewable-based energy system is planned and scaled using the real-time data use of domestic hot water (DHW), heating and electricity necessary for the buildings. PVT panels are used in the hybrid solar and biomass-based energy systems to produce both the DHW requirements and the electricity production. The digester is used with the heat pump, which generates heat. A double-effect absorption refrigeration system is also utilized to provide the necessary cooling requirements. On the supply side, the management of the heat streams and the redirection of flows are done using a rule-based regulating system. The whole plant's size is supplied, and the dynamic energy simulation is run. The primary deciding criteria for heating the buildings are the costs of electricity and biomass. The whole system is then optimized depending on operating circumstances, and the outcomes are compared to the design point. PVT may be used to create more than 80 % of the yearly DHW. Furthermore, summertime radiation accounts for 64.8 % of cooling output since it is more intense and may be converted into cooling energy. Digester/CC also contributes 66.55 % of the building's heating, showing that the designers should rely on biomass as wintertime energy costs are higher. The parametric study demonstrates that increasing PVT time and tank capacity has varied effects on efficiency and emissions. Also, On winter days, there was a significant drop in renewable energy generation from summer to autumn, from 82.7 MWh to 28.52 MWh. The optimization results show that at the TOPSIS point, the total cost, efficiency, and emission index are 9.73 $/hr, 36.8 %, and 7.75 kg/MWh, respectively.

Solid-state Hydrogen storage: influence of storage capacity in physisorption

Abstract Hydrogen storage in solid-state is a promising alternative to conventional technologies to overcome some of their limitations, particularly in terms of the amount of hydrogen stored per unit volume. For instance, liquid hydrogen (stored at 1 bar and 20 K) is characterized by a 70.8 kg/m3 volumetric density, but a great amount of energy is required for liquefaction (about 12.5 kWh/kg); whereas, hydrogen stored as compressed gas (350 - 700 bar) at ambient temperature reaches a density ranging from 24.5 to 41.4 kg/m3, however the compression work is significant, and the high storage pressure determines safety issues. Regarding solid-state hydrogen storage, chemisorption is a solution, where hydrogen is stored at moderate pressure and temperature, reaching a volumetric density of 80-110 kg/m3, but between hydrogen and metal hydrides chemical bonds born, which require a significant amount of energy to be break them; moreover, the time required for absorption and desorption is very low. In the context of solid-state storage, carbon materials can be an interesting solution due to their low cost, and their ability to store hydrogen reversibly within a porous structure through physisorption mechanisms, under supercritical conditions. This study numerically investigates the effect of the variation of the tank capacity on the charging, dormancy, and discharging processes. Two similar axi-symmetric geometries are considered by doubling the tank volume from V 1 = 2.5 L to V 2 = 5 L. The physisorption mechanism has been modeled according to the modified Dubinin-Astakhov isotherm model. Initially, the CFD model has been validated on V 1 tank against experimental results available in the literature. Then, simulations have been carried out on V 2 tank to estimate the effect of a storage capacity increase. The simulations on the V 2 tank have been set keeping the same boundary conditions in terms of velocity, density, and temperature at the inlet by doubling the overall amount of hydrogen stored with respect to V 1 tank. The results show corresponding trends in temperature and pressure profiles with only slight differences in their behaviors; in particular, in the final stage of the charging process.

Optimal rule-based energy management and sizing of a grid-connected renewable energy microgrid with hybrid storage using Levy Flight Algorithm

The study addresses the integration of hybrid hydrogen (H2) and battery (BT) energy storage systems into a renewable energy microgrid comprising solar photovoltaic (PV) and wind turbine (WT) systems. The research problem focuses on improving the effectiveness and computational efficiency of energy management systems (EMS) while ensuring high system reliability. Despite the existing optimization methods for hybrid microgrids, challenges remain in optimizing energy storage and capacity planning in grid-connected microgrids. To solve this, we propose the use of the Levy Flight Algorithm (LFA) to optimize the capacities of PV, WT, H2 tanks, electrolyzers (EL), fuel cells (FC), and BT, which presents a complex nonlinear optimization challenge. The novelty of this study lies in integrating the LFA with a rule-based EMS, enhancing system reliability and efficiency. The proposed approach significantly reduces the annualized system cost (ASC) and the levelized cost of energy (LCOE). The result demonstrate that the LFA outperforms methods like the Salp Swarm Algorithm (SSA), Particle Swarm Optimization (PSO), Grey Wolf Optimization (GWO) and Genetic Algorithm (GA), yielding cost savings of $3,309, $5,297, $4,484, and $5,129 respectively. The LFA achieves the lowest LCOE at $0.275/kWh, compared to $0.278/kWh with SSA, $0.289/kWh with GA, $0.280/kWh with PSO and $0.283/kWh with GWO. This research contributes to the broader scientific community by providing a more efficient approach to optimizing renewable energy microgrids with hybrid storage systems, thus promoting eco-friendly and cost-effective energy solutions. The proposed system design offers a pathway to future energy systems with high renewable integration, especially as technology advances and costs continue to decrease.

Designing an Economical Water Harvesting System Using a Tank with Numerical Simulation Model WASH_2D

Newly incorporated module into the WASH_2D model has enabled simulating a rainwater harvesting system (RWHS) using a tank. The incorporated module in WASH_2D was tested for two field experiments to determine the optimal tank capacity and cultivated area that give the highest net income for farmers. The first experiment was composed of treatments A, B, and C having the same cultivated and harvested areas (plastic sheets) of 24 m2 and 12.5 m2, respectively. The capacity of the tanks for treatments A, B, and C was set at 500, 300, and 200 L, corresponding to storability of 21, 13, and 8 mm, respectively, while in the second experiment we carried out three treatments: F, G, and H having the same tank capacity of 300 L and harvested area of 12.5 m2 with variable cultivated areas as G and H were larger by two and three times than F (10.5 m2), respectively. Water was applied automatically through a drip irrigation system by monitoring soil water suction. Results of the first experiment showed that the optimal storability and seasonal net income simulated by WASH_2D were 17 mm and 5.82 USD yr−1, which were fairly close to 18 mm and 5.75 USD yr−1 observed from field data, respectively. Similarly, the results of the second experiment revealed that simulated net incomes for different cultivated areas agreed well with the observed data. We concluded that the use of the simulation model WASH_2D can be economically useful to promote small-scale irrigation in semi-arid regions and guide planning irrigation or rainwater harvesting investments.

Determination of Pesticide Exposures of Some Nozzle Types in Almond Trees Sprayed with Knapsack Sprayer

In this study, field trials were conducted using a knapsack sprayer to determine the pesticide exposure of the pesticide application agricultural workers (The operators) in almond tree spraying, and pesticide exposure was determined by the whole-body approach technique. An electric knapsack sprayer with a 20-liter tank capacity was used in the study. The nozzles attached to the spray boom of the knapsack sprayer can be changed in practice. Three spray nozzles were used to measure the operator pesticide exposure. These nozzles are (M1) Air induction nozzle (11002), (M2) Extended range flat fan nozzle (XR 11002), and (M3) Hollow cone nozzle (TXA8002). Each method was applied at two different spray distances (50 and 100 cm), and water-sensitive papers (WSP) were used as a sample surface in all methods. When protective clothing was analyzed, it was found that the whole body could be exposed to pesticides. According to the results, the highest coverage was obtained from standard extended range flat fan nozzle (M2) method with a 23.6 (% coverage) coverage rate and deposition of 3,956 (µL.cm-²).

Efficiency evaluation of wastewater treatment by three macrophytes using a pilot-constructed wetland system in Ota, Nigeria.

Three aquatic macrophytes were used to treat wastewater using a pilot-constructed wetland (CW) system to determine the most efficient plants for removing contaminants from wastewater. The three macrophytes are water hyacinth (Eichhornia crassipes), water lettuce (Pistia stratiotes), and duckweed (Lemna minor). Three 150 L capacity tanks with sand and gravel as substrates were used as the pilot CW for each plant. Upon initial examination, the raw wastewater was not compliant with standard discharge limits. The wastewater samples were collected every 7 days for 3 weeks for treatment. From the findings, at 14 days hydraulic retention time (HRT), E. crassipes and P. stratiotes achieved the highest total phosphorus (TP) and chemical oxygen deman (COD) reductions of 99.3 and 99.4%, respectively. E. crassipes indicated better biological oxygen demand removal efficiency of 91.3%, COD (85.0%), electrical conductivity (90.4%), total dissolved solids (89.7%), and total coliforms (66.0%). Albeit, P. stratiotes indicated better results for total suspended solids (96.2%), TP (7.55%), and E. coli (94.4%), while L. minor was better with 90.8% total nitrogen removal. The overall analysis showed E. crassipes to be more efficient than the three macrophytes. However, the other two plants are replaceable options and large-scale implementation of this project in the community would be a major contributor to actualizing SDG number 6.

Adaptation climate change through application of green infrastructure household scale rainwater harvesting in tropical coastal areas based fuzzy logic

Freshwater problems in coastal areas include the process of salt intrusion which occurs due to decreasing groundwater levels below sea level which can cause an increase in salt levels in groundwater so that the water cannot be used for water purposes, human consumption and agricultural needs. The main objective of this research is to implementation of RWH to fulfill clean water needs in tropical coastal area in Tanah Merah Village, Indragiri Hilir Regency, with the aim of providing clean water to coastal communities. The approach method used based on fuzzy logic (FL). The model input data includes the effective area of the house’s roof, annual rainfall, roof runoff coefficient, and water consumption based on the number of families. The BWS III Sumatera provided the rainfall data for this research, which was collected from the Keritang rainfall monitoring station during 2015 and 2021. The research findings show that FL based on household scale RWH technology is used to supply clean water in tropical coastal areas that the largest rainwater contribution for the 144 m2 house type for the number of residents in a house of four people with a tank capacity of 29 m2 is 99.45%.

Experimental study on the effects of integrating phase change material with a solar updraft tower

AbstractThe solar updraft tower power plant presents a promising renewable energy solution but faces limitations in thermal efficiency and energy production during nonsunny hours. This study addresses a critical gap in the literature by investigating the integration of latent heat storage systems utilizing paraffin wax as phase change materials (PCMs) to enhance solar updraft tower (SUT) performance. Two identical small‐scale SUTs were constructed, both using the same tank configuration; however, the PCM device was filled with paraffin wax as a PCM, while the non‐PCM device contained only atmospheric air. Three scenarios were explored, featuring varying PCM tank heights of 2, 4, and 6 cm (the full capacity of the PCM tank). Results indicated that, from 3 p.m. until sunset, the PCM‐integrated SUT in Case 3 (with 6 cm of PCM) achieved the best performance, with an average absorber temperature rise of 25°C, compared with 12°C for the non‐PCM device. During the same period, the average air velocity at the tower neck, where a wind turbine could be installed, was 1.21 m/s for the PCM device, versus 0.82 m/s for the non‐PCM device. Notably, the nocturnal operating time extended significantly with PCM use, rising from 90 min for the 2 cm case to 125 min for the 6 cm case. In contrast, the non‐PCM device exhibited no operational time after sunset. This research not only demonstrates the effectiveness of PCM in improving the thermal performance and operational longevity of SUTs but also introduces a novel tank configuration that allows for flexible PCM integration, representing a significant advancement in the development of more efficient SUT systems.

Influence characteristic and improvement mechanism of thermal storage performance of Packed-bed thermocline tank based on high-temperature molten salt

Chloride salts and carbonates thermal energy storage (TES) have great application potential in high-temperature concentrated solar power (CSP) plants. However, their thermal storage characteristics, performance improvement mechanism and economic feasibility of application in high-temperature conditions are not clear. In this study, a transient, two-dimensional and axisymmetric model is developed for packed-bed thermocline tanks. The effects of six commonly solid fillers on thermal storage performance of NaCl-KCl-MgCl2 salt and Na2CO3-K2CO3-Li2CO3 salt at an operation temperature of 450–800 °C are simulated. The suggestions for optimizing fillers are provided combined with thermal and economic performance. Results show that high volume heat capacity and low thermal conductivity of fillers play important roles in deferring migration and weakening diffusion of thermocline, thus promoting thermal storage capacity and efficiency of tanks. Concrete and cast iron are suitable fillers for chloride salts and carbonates TES. The concrete tank is suitable for systems with strict cost control and low TES requirements. The iron tank is suitable for systems with high TES and low cost control requirements, which significantly increases effective thermal storage capacity of chloride salts by 222.1 % and considerably reduces TES cost of carbonates by 41.1 %. The results can be beneficial for high-temperature TES system of CSP plants.

Impact of Water Quality and Phytoplankton on Juvenile Vannamei Shrimp Growth in Low-Salinity Ponds

The Vannamei shrimp (Litopenaeus vannamei) is a key species in global aquaculture, with its growth influenced by various environmental factors and nutritional quality. This study aimed to analyze water quality parameters and phytoplankton density, as well as assess the growth of juvenile Vannamei shrimp in circular ponds with low salinity (5-6 ppt). Shrimp were stocked at a density of 80 individuals per square meter in 5-ton capacity tanks and fed four times daily over a 30-day period. Water quality parameters, including temperature, dissolved oxygen, pH, and light intensity, were monitored bi-daily, revealing fluctuations that impacted shrimp health. Notably, plankton density assessments showed Cyclotella present on day 14 but absent on day 28, while Microcystis and Rhizosolenia were detected on day 28, indicating shifts in the phytoplankton community. The specific growth rate (SGR) of shrimp was measured at 18.69% per day, with initial and final weights recorded at 0.01 ± 0.00 g and 2.72 ± 0.23 g, respectively. This study highlights the importance of maintaining optimal water quality and understanding phytoplankton dynamics for enhancing shrimp growth. Additionally, it explores the potential benefits of alginate supplementation and the effects of low salinity on the growth of juvenile Vannamei shrimp, contributing valuable insights for sustainable aquaculture practices.

Optimization and analysis of the inflow distribution influence on the middle discharge blow tank pneumatic conveying characteristics

The influence of different inflow gas distribution modes on the pneumatic conveying characteristics of the middle discharge blow tank was studied using an in-house pneumatic conveying experimental setup. The flow rates of pressurized gas, supplementary gas, and fluidized gas were varied in this study. The gas distribution mode was then optimized to improve the energy efficiency of the blow tank of a pneumatic conveying system. The results show that the particle mass flow rate, the solid-to-gas ratio, and the pressure drop increase first and then decrease with the pressurized gas and fluidized gas valves opening. In the case of supplementary gas, the particle mass flow rate and solid-to-gas ratio increase first and then decrease. However, an opposite trend is observed for the pressure drop, which decreases first and then increases. The results highlighted that the optimized gas distribution mode increases the mass flow rate of particles and the solid-to-gas ratio by 28.48% and 15.15%, respectively. The pressure drop of the blow tank has also increased slightly, by 0.88%. Therefore, the delivery capacity and efficiency of the middle discharge blow tank are greatly improved at the cost of a slight increase in energy consumption.

АНАЛИЗ ТИПОВ И РАЗЛИЧНЫХ КОНСТРУКТИВНЫХ ОСОБЕННОСТЕЙ РЕЗЕРВУАРОВ (РЧВ), ПРИМЕНЯЕМЫХ В СИСТЕМАХ ПОДАЧИ И РАСПРЕДЕЛЕНИЯ ВОДЫ

The paper presents a list and analysis of the design of clean drinking water tanks, which have become widespread in the systems of household drinking, industrial, fire-fighting water supply. Subject of research: Reservoirs of clean drinking water, erected in various ways and made of various materials. Materials and methods: The work summarizes reference data, data from sites of modern equipment that implement tanks of various design designs, presents material on the stage Materials and methods: The paper summarizes reference data, data from sites of modern equipment that implement tanks of various design designs, presents material on the stages of construction of tanks for various purposes Results: A table of summary data covering the ranges of capacities of clean drinking water tanks has been compiled, with the definition of the required area for each of them. The data presented in the work as a result of generalization, allows at the stage of preliminary calculations to determine the necessary parameters for the placement of clean water reservoirs: (the area of the cutting of the vegetation layer, the depth of the excavation, the volume of excavation, etc.). Conclusions: The research results allow us to obtain a summary table of RFV data that allows us to determine the type and structural elements of storage equipment, the presented material is useful for students, specialists of design and operational organizations.

Investigating the impacts of a recirculation sedimentation application on microalgae biomass cultivation in wastewater treatment

Commercial microalgae production is often interrupted by contamination, leading to short production cycles, reinoculation needs, and culture collapses, significantly increasing costs. This study focuses on investigating Recirculated Sedimentation Application (RSA) to control contamination in microalgae culture systems used for wastewater treatment. Chlorella vulgaris culture was grown in an unsterilized mixture of tertiary treatment effluent and centrate of anaerobic digestion wastewater sludge over a 90-day experimental period. 60 L raceway reactor was operated under a light intensity of 275 μM m−2.s−1 with a 16:8 h light-dark photoperiod. To evaluate the effect of RSA on biological-based problems, the experiment was conducted in three phases. The benefits of utilizing RSA were established through the following observations: effective removal of contaminants at an acceptable level without releasing the culture; extension of the biofilm formation time on the inner walls; inhibition of heterotrophic bacteria and nitrification; enhancement of the suspended solids retention capacity of the raceway tank (up to 770 mg.L−1); and improvement in ammonium removal rate to approximately 30 mg.L−1d−1. The ideal salinity level for both ammonium removal and biomass concentration in RSA should be below 0.02%. These findings demonstrate the potential of phycoremediation for sustainable wastewater treatment and contribute to environmental bioremediation strategies.

APLIKASI IRIGASI TETES BERTINGKAT PADA TANAMAN SEMUSIM MENDUKUNG KETAHANAN PANGAN KELUARGA DI LINGKUNGAN PERMUKIMAN KOTA MATARAM

The use of multistage drip irrigation needs to be supported by adequate planting media so that irrigation water can be provided optimally. The planting medium used is practically soil mixed with compost and put in a polybag. Therefore, by adding compost with a certain composition to the soil, it is hoped that a good planting medium will be obtained. This test aims to determine the effect of using cocopeat compost and cow compost as well as soil as a planting medium in polybags on providing multistage drip irrigation. Flow characteristics on the distribution of irrigation water, its absorption capacity, absorption rate and irrigation uniformity achieved. The test was carried out on a ½” PVC drip irrigation network with a 2 lt/hour emitter consisting of 4 network levels on land measuring 2m x 4m, water source from a tower with a height of around 2.5m and a tank capacity of 150 liters. Test data for analysis consists of irrigation volume and distribution, drip system flow rate, irrigation uniformity (Cu), infiltration rate and irrigation depth. The analysis results show that the average irrigation distribution on floors 1 to 4 is 3028ml, 2937ml, 2848.25ml and 2793 ml, with flow rates on floors 1 to 4 of 40ml/s, 39 ml/s, 38 ml/s and 37 ml/sec. The amount of drip discharge (qt) on the 1st floor was 6.7ml/sec, on the 2nd floor the amount was 6.5 ml/sec, on the third floor it was 6.3 ml/sec and 6.2ml/sec on the 4th floor. Irrigation uniformity was obtained by 96% is considered very good, with an average infiltration rate hc in V2 of 0.04 cm/s, in V3 the hc was 0.03cm/s and in V4 the hc was 0.027cm/s. So the irrigation infiltration rate when using cocopeat tends to decrease if the portion of the planting medium increases, so its use needs to be limited.

Experimental and numerical study on the flow and heat transfer of ring-ribbed tank in deep-sea manned submersible

The ring-ribbed tank is the key equipment of cooling system of deep-sea manned submersible. The heat transfer characteristics of the outer wall and the heat transfer and flow characteristics of the inner flow channel of the ring-ribbed tank for different inlet and outlet temperatures and flow rates were studied through a water tank test. The results indicate that Nusselt number for the inner flow channel correlates with Reynolds and Prandtl numbers, while for the outer wall, it correlates with Grashof and Prandtl numbers with an overall error within 5%. A numerical study using the Realizable k-ε turbulence model and Boussinesq approximation of the flow-solid conjugate heat transfer is conducted, which can accurately determine the heat exchange capacity and the import and export differential pressure with an average relative error of 1.98% for hot water temperature and 7.73% for shell wall temperature. Additional simulations for determining the heat transfer capacity and flow resistance characteristics of the ring-ribbed tank in open water results demonstrate that the differential pressure and its coefficient are basically consistent with model test results. The cooling system can achieve a heat transfer rate of up to 17 kW with an external seawater flow velocity of approximately 2 knots.