Tank Size Research Articles

Membranes for Aqueous All Vanadium Redox Flow Battery

Redox Flow Battery (RFBs) are electrochemical devices that store electrical energy in soluble electro-active species dissolved in a liquid electrolyte. All Vanadium Redox Flow Batteries (VRFB) is one of the most promising and suitable technologies for large-scale energy storage for a wide range of renewable power sources. The RFB system separates capacity from power density: the capacity of the battery being determined by the size of the electrolyte tanks (the larger the volume of the electrolyte solutions, the higher the capacity of the battery), the system power is determined by the size of cell stacks. The flexible design, showed by this system, allows an easy scale up, but it is necessary to develop stable and high energy density redox electrolytes and efficient and low cost membranes or separators.[1] The membrane is a critical component that to a great extent determines the performance of RFB systems for practical applications The membrane is responsible for electronically insulating the negative and positive compartments while allowing the transport of charge balancing ions to complete the circuit. A membrane that exhibits excellent ionic conductivity, low permeability of the active species, and high chemical stability, is thus critically important for the development of RFB technologies. Perfluorosulfonic polymers such as Nafion are commonly used in different electrochemical devices, like Polymeric Fuel Cell (PEM), electrolyzers or RFB, due to their high proton conductivity, good chemical and thermal stability. However, when used in VRFBs, Nafion membranes suffer from the crossover of vanadium ions which results in decreased energy efficiency. So far studies are concentrated on the development of novel composite membranes leading to a low self-discharge rate and low costs. In this work, several cation exchange membranes (CEM) to be used in aqueous electrolyte VRFBs were investigated. Our approach to reduce costs and vanadium-ion crossover was based on the use of sulfonated poly ether ether ketone (SPEEK) due to its low permeability of diffusing specie and high ionic conductivity. Moreover, to further block vanadium-ion permeability through the membrane, we also evaluated the effect of adding a filler in the polymer matrix. In particular, an organically-modified ceramic material (TiO2-RSO3H) was synthesized by covalently grafting propylsulfonic acid groups on the surface of TiO2 nanoparticles [2] and added into the ion exchange polymer. To obtained homogeneous composite membranes two different deposition techniques were evaluated: solution casting and air spraying method. Filled and unfilled Nafion membranes were prepared and used as reference. Permeability measurements were carried out using a static H-type glass cell and the vanadium concentration were evaluated by UV-Vis spectrophotometry. The ionic conductivities of cation exchanged membranes was evaluated by electrochemical impedance spectroscopy. Coulombic and energy efficiencies of the system were studied by galvanostatic charge-discharge cycles using a lab-scale RFB cells. The overall performance of the RFB system was further analyzed by polarization curve at different state of charge (SOC) and Electrochemical Impedance Spectroscopy (EIS). Changes in the electrolyte composition were studied with cyclic voltammetry (CV) and UV-vis spectroscopy. Early insights on the understanding of battery capacity loss in long-term cycling tests is also reported in this work. Reference [1] Aishwarya Parasuramana, Tuti Mariana Lima, Chris Menictasc, Maria Skyllas-Kazacos, Electrochimica Acta, 101, 2013 , 27-40 [2] D. Cozzi, C. de Bonis, A. D’Epifanio, B. Mecheri, A. C. Tavares, S. Licoccia Journal of Power Sources 248, (2014) 1127-1132

Size effect of nanoparticle on specific heat in a ternary nitrate (LiNO3–NaNO3–KNO3) salt eutectic for thermal energy storage

In this study we investigate the effect of nanoparticles on the specific heat of ternary nitrate salt eutectic doped with nanoparticles. Four different sizes of SiO2 nanoparticles were tested: 5nm, 10nm, 30nm, and 60nm. They were doped into ternary nitrate salt eutectic (LiNO3–NaNO3–KNO3) at 1% concentration by weight. Ternary nitrate salt eutectic has been considered as advanced thermal energy storage material due to its lower melting point and high thermal stability. Enhancing the specific heat of ternary nitrate salt eutectic can greatly increase its thermal storage density. This can not only reduce the material cost but also the size of pipe and storage tanks and, therefore, energy storage cost can be significantly reduced. A modulated differential scanning calorimeter was employed to measure the specific heat of ternary nitrate salt eutectic before and after doping with nanoparticles. According to the conventional specific heat model (density weighted rule), the specific heat of ternary nitrate salt eutectic should slightly decrease after doping with nanoparticles since the concentration of nanoparticles is very small (∼1% by weight) and the specific heat of nanoparticles is lower than that of ternary nitrate salt eutectic. However, the specific heat of the mixture was measured to be enhanced by 13–16% and no significant variation in specific heat was observed with nanoparticle size. From subsequent material characterization study, we observed a large amount of nanometer-sized structure formed by the salt compound around nanoparticles. Nanostructure has extremely large specific surface area. This can amplify the effect of surface energy on the effective specific heat (which was often negligible on a macroscale) and can be primarily responsible for the enhanced specific heat with doping nanoparticles.

Parametric Analysis of a Passive Energy Management Through Increased Thermal Capacitance

This paper evaluates the influence of several parameters on the potential of using increased thermal capacitance (ITC) as a passive energy management technique to decrease a building’s cooling load. ITC is implemented by circulating water from a storage tank through a piping system located in the building’s ceiling. The cooling load of the ITC enhanced building is compared to the cooling load of a reference building without ITC. TRNSYS, a transient system simulation software, is used to simulate both the ITC enhanced building and the reference building. The following parameters that affect the performance of the ITC are analyzed: tank size, specific heat, mass flow rate, initial temperature of the working fluid, pipe material and wall thickness, and location of the piping system in the ceiling. These parameters are also modified to achieve the best results for each of the climate conditions investigated. The simulations demonstrate that ITC has the potential to reduce the overall cooling load in a range between 4% to 8%, depending on the location and the month of the year.

In situ sludge magnetic impregnation (ISSMI) as an efficient technology for enhancement of sludge sedimentation: Removal of methylene blue using nitric acid treated graphene oxide as a test process

In this research, a novel technology called “In Situ Sludge Magnetic Impregnation” (ISSMI) was introduced, aimed at increasing the rate of sludge sedimentation and decreasing sludge volume index. Efficiency of the process was investigated through removal of methylene blue using nitric acid treated-graphene oxide (NAT-GO). In this technique, both magnetic nanoparticles and non-magnetic graphene oxide were added to wastewater, separately. During sludge formation, magnetic nanoparticles were trapped between sludge particles. As a consequence of sludge impregnation, magnetic sludge was achieved which settled quickly by a magnet. An enhancement sedimentation factor of 66.3 was obtained as the ratio of time at which 50% of sludge settled without and with magnetic impregnation. This can lead to a considerable decrease in hydraulic retention time which makes it possible to reduce the size of sedimentation tank. This method requires significantly lower amount of magnetic nanoparticles for sludge sedimentation compared to methods based on magnetic nanocomposite. Furthermore, sludge volume index decreases due to magnetic force. In order to increase the adsorption capacity of GO, it was treated with nitric acid. Langmuir isotherm was fitted to adsorption data, resulting in maximum adsorption capacity of 1242mgg−1.

Potential for Potable Water Savings in Buildings by Using Stormwater Harvested from Porous Pavements

There is a growing concern about the scarcity of water resources due to population growth and increased demand for potable water. Thus, the rational use of water has become necessary for the conservation of such resources. The objective of this study is to estimate the potential for potable water savings in buildings of different sectors—residential, public and commercial—in the city of Florianópolis, southern Brazil, by using stormwater harvested from porous pavements. Models were constructed to assess infiltration and rainwater quality; samples of stormwater from a local road were collected to evaluate its quality; and computer simulation was performed to assess the potential for potable water savings and rainwater tank sizing. Draining asphalt concrete slabs with two types of modifiers were used, i.e., tire rubber and SBS polymer—styrene-butadiene-styrene. The Netuno computer programme was used to simulate the potential for potable water savings considering the use of rainwater for non-potable uses such as flushing toilets and urinals, cleaning external areas, and garden watering. Average stormwater infiltration was 85.4%. It was observed that stormwater is not completely pure. From the models, the pH was 5.4 and the concentrations of ammonia, phosphorus, nitrite, and dissolved oxygen were 0.41, 0.14, 0.002, and 9.0 mg/L, respectively. The results for the stormwater runoff of a paved road were 0.23, 0.11, 0.12, 0.08, 1.41, 2.11, 0.02, and 9.0 mg/L for the parameters aluminium, ammonia, copper, chromium, iron, phosphorus, nitrite, and dissolved oxygen, respectively; and the pH was 6.7. In the city of Florianópolis, which has a surface area of paved roads of approximately 11,044,216 m², the potential for potable water savings ranged from 1.2% to 19.4% in the residential sector, 2.1% to 75.7% in the public sector and 6.5% to 70.0% in the commercial sector.

Optimized design and operation of heat-pipe photovoltaic thermal system with phase change material for thermal storage

This work aims to optimize the design and operation of a heat pipe photovoltaic-thermal (HP-PV/T) panel integrated with a phase change material (PCM) thermal storage water tank to produce electricity and hot water for an office building. A transient mathematical model for the integrated HP-PV/T-PCM system was used to predict its performance for known environmental and solar conditions and PCM melting point. The validated model was applied on a typical office space in the city of Beirut to obtain an optimal design using a derivative free genetic algorithm. The incremental system cost associated with a heat pipe and PCM tank was used in the optimization to obtain a design resulting in minimum annual auxiliary heating cost to meet the hot water demand while providing the electricity needs at a lower number of PV panels due to improved efficiency. An optimal system of 4 kW (20 PV panels each at 1.6 m2) was found to meet the electric power needs all year round. The optimal PCM storage tank size per panel was 37 l at PCM total mass of 22.42 kg with melting temperature of 33 °C.

Comparison of water quality in live shellfish retail holding tanks


 Background: Water quality in live retail shellfish holding tanks are vital in increasing shellfish quality and reducing risk of shellfish-associated outbreaks. Poor holding tank water conditions may not only cause mortality of shellfish, but also allow for harmful pathogens to contaminate the shellfish, proliferate in the holding tanks, and ultimately potentially affect consumer health. Shellfish are processed and handled at a variety of levels at the retail stage. Therefore, the purpose of this research project is to compare water quality in live retail shellfish holding systems between processing plants and retail food markets. Differences may indicate a need for attention at a particular level in order to effectively and efficiently reduce mortality and disease among shellfish, and thus potentially humans as well. Methods: 30 water samples were taken from the two types of locations with the help of the Department of Fisheries and Oceans (DFO), Ministry of Agriculture, and the BCCDC. These samples were tested for parameters including temperature, pH, nitrites, turbidity, and dissolved oxygen using a LaMotte Fresh Water Aquaculture Kit and a HACH 2100P turbidimeter. A two-tailed t-test was used to compare the means of each of the parameters among the two types of locations with live shellfish holding tanks. Results: The mean values for all parameters in both retail and processing met the requirements set by the BCCDC. However, temperature and dissolved oxygen showed statistically significant differences between retail markets and processing facilities. Nitrites, pH, and turbidity showed no statistically significant differences between the two types of locations. Conclusion: Differences in dissolved oxygen may have been due to salt levels, failing recirculation systems, or high levels of organic matter from sanitation issues. Differences in temperature may have been due to differences in holding tank size, or inconsistencies from using two different thermal measuring devices. High levels of nitrites were a concern as well due to overcrowding of holding tanks. More attention may be needed for these issues, especially during certain seasons such as Chinese New Years, in order to lower the risk to public health.

Analytical study of failure damage to 270,000-kL LNG storage tank under blast loading

The outer tank of a liquefied natural gas (LNG) storage tank is a longitudinally and meridianally pre-stressed concrete (PSC) wall structure. Because of the current trend of constructing larger LNG storage tanks, the pre-stressing forces required to increase wall strength must be significantly increased. Because of the increase in tank sizes and pre-stressing forces, an extreme loading scenario such as a bomb blast or an airplane crash needs to be investigated. Therefore, in this study, the blast resistance performance of LNG storage tanks was analyzed by conducting a blast simulation to investigate the safety of larger LNG storage tanks. Test data validation for a blast simulation of reinforced concrete panels was performed using a specific FEM code, LS-DYNA, prior to a full-scale blast simulation of the outer tank of a 270,000-kL LNG storage tank. Another objective of this study was to evaluate the safety and serviceability of an LNG storage tank with respect to varying amounts of explosive charge. The results of this study can be used as basic data for the design and safety evaluation of PSC LNG storage tanks.

Hot sanitary water production with CO2 heat pumps: Effect of control strategy on system performance and stratification inside the storage tank

In this work three different control strategies for the production of sanitary hot water by means of an electric heat pump working with CO2 are investigated. The heat pump is a prototype, here modelled in the vapour-compression software package IMST-ART. By simulating this model, the performance of the heat pump is correlated to the boundary conditions and is scaled to different sizes, namely 1, 1.5, and 2 times larger than the reference system. After having chosen an application for which the load profile of sanitary hot water during the year is known, these heat pumps are simulated in a TRNSYS16 model where the production of sanitary hot water and the consumption are buffered by the presence of a tank. Key parameter in guaranteeing comfort and good performance of the system is the stratification inside the storage tank. The size of the tank necessary to keep a certain level of comfort at the user is then determined through a parametric analysis for each size of the heat pump. The energetic performance is also evaluated for each system in terms of seasonal performance factor. Then, the results obtained are compared with a different system where the heat pump is equipped with an inverter and the circulation pump follows a different control logic. The size of the tank and the seasonal performance factor are therefore determined in this case too. Moreover, a “night&day” control logic is compared to these first two options to have a baseline of comparison in terms of volume of storage needed to guarantee a same level of comfort and performance. To provide information also on the running costs, a parametric analysis was run varying the type of control, the heat pump and the tank sizes for different load profiles.The results show that the size of the heat pump has a significant effect on the comfort of the user, which usually leads to oversizing of the storage tank when the load profile is unknown. With regard to this, the results obtained for the alternative control system show a 20% reduction of the volume of the tank, given a certain level of comfort, and is therefore useful to reduce the size of the storage tank.

Performance modeling and parametric study of a stratified water thermal storage tank

Thermal energy storage (TES) can significantly increase the overall efficiency and operational flexibility of a distributed generation system. A sensible water storage tank is an attractive option for integration in building energy systems due to its low cost and high heat capacity. As such, this paper presents a model for stratified water storage that can be used in building energy simulations and distributed generation simulations. The presented model considers a pressurized water tank with two heat exchangers supplying hot and cold water respectively, where 1-D transient heat balance equations are used to determine the temperature profiles at a given vertical location. The paper computationally investigates the effect of variable flow-rates inside the heat exchangers, the effect of transient heat source, and buoyancy inside the tank induced by location and length of the heat exchangers. The model also considers variation in thermophysical properties and heat loss to the ambient. TES simulation results compare favorably with similar 1-D water storage tank simulations, and the buoyancy model presented agrees with COMSOL 3-D simulations. The analysis shows that when the inlet hot fluid temperature is time dependent, there is a phase lag between the stored water and the hot fluid temperature. Furthermore, it was observed that an increase in flow-rate inside the hot heat exchanger increases the stored water and the cold water outlet temperature; however, the increment in temperature observes diminishing returns with increasing flow-rate of hot fluid. It was also noted that for either heat exchanger, increasing the vertical height of the heat exchanger above a certain value does not significantly increase the cold fluid outlet temperature. Results from the model simulations can assist building designers to determine the size and configurations of a thermal storage tank suited for a given distributed generation system, as well as allowing them to accurately predict the fraction of heat generated by the system that could be stored in the tank at a given time when charging, or the fraction of heating load that could be met by the tank when discharging.

Effect of the Different Shapes of Air Diffuser on Oxygen Mass Transfer Coefficients in Microporous Aeration Systems

It is common to apply aeration facility in lakes, rivers, estuaries and ponds where the dissolved oxygen concentration needs to be increased. Among sufficient aeration facilities, the microporous aeration systems, with advantaged energy-saving, environmental protection, easy installation, adaptability and other good characteristics, are popular for aquaculture ponds or aeration tank in sewage treatment plant. A microporous aeration system mainly includes an air compressor, air diffuser and air supply line to connect air compressor and air diffuser, where air diffuser is often empirically a disc rolled up by a length of aeration tube. In fact, what kind of shape rolled up by the length of aeration tube is still an open question for optimal oxygen mass transfer coefficient. So a series of re-oxygenation experiments were attempted under different shapes of air diffuser rolled up by a same length of aeration tube in laboratory. The shapes were I-shape, C-shape, S-shape and Disc-shape. The experimental apparatus mainly includes one glass tank, a microporous aeration system and a dissolved oxygen meter. The sizes of the glass tank were 2 m × 0.8 m × 0.8m (length × width × height). The different shapes of air diffuser were fixed in the center of the tank bottom. The diffused-air flow rate was set among 0.6-1.8m3/h and the water depth was set of 0.4 m, 0.55m, 0.7m. Based on the Standard Test Method for Oxygen from American Society of Civil Engineers (ASCE), the oxygen volumetric mass transfer coefficients were calculated. The results showed that the optimal aeration efficiency is under the use of I-shaped diffuser, and then C-shaped and disc-shaped diffuser, the poorest one is the use of S-shape. When the air-free water surface mass transfer was cut off by covering plastics film on the top of the tank, the oxygen volumetric mass transfer coefficients of I-shaped, C-shaped, S-shaped and disc-shaped diffusers were decreased. The best aeration performance is I-shape, the poorest one is S-shape.

Sizing of the Vacuum Vessel Pressure Suppression System of a Fusion Reactor Based on a Water-Cooled Blanket, for the Purpose of the Preconceptual Design

A methodology to preliminarily evaluate the size of the suppression tank and the relief pipes for a Vacuum Vessel Pressure Suppression System, to be adopted in a fusion reactor based on a water cooled blanket, is presented. The volume of the ST depends on the total energy of the water cooling system and it can be sized based on a required final pressure at equilibrium, by a simple energy balance. The pressure peak in the VV depends mainly on break area and the flow area of the relief pipes and some suggestions about the method for a preliminarily evaluation of their size are discussed. The computer code CONSEN has been used to perform a parametric study and to verify the methodology.

Improvement of the Purification Technology of Natural Waters in Waterworks in the Steppes and the Desert Zone

The most important task of housing and communal services is to provide a high-quality drinking water to the population. It is necessary to improve the existing traditional water supply system and to develop new means of water treatment.Processing of the wash water and sludge produced during water treatment due to technical imperfections of the recommended methods. Cleaning of wash water and sediment is an important issue and should always be dealt with in conjunction with the preparation of drinking water at waterworks. The main results of the sedimentation process studies slurry in water treatment at waterworks Lower Volga region of steppe and desert zones are presented. Complex investigations in filtering the washing water have been performed It is shown that the main characteristic in determining the size of horizontal tanks is the quantity of a minimum hydraulic size of suspended particles regardless of the geographical area.

Investigation of Microstructure in Solid State Welded Al-Cu-Li alloy

Al-Li alloys have been extensively used in aerospace vehicle structure since the presence of lithium increases the modulus and reduce the density of the alloy. Especially the third generation Al-Cu-Li alloy shows enhanced fracture toughness at cryogenic temperatures so that the alloy has been used on the fuel tank of space launchers, like Super Lightweight External Tank of the Space Shuttle. Since the commercial size of the plate cannot accommodate the large tank size of the launcher, joining several pieces is required. However, lithium is highly reactive and its compounds can decompose with heat from conventional fusion welding and form different types of gases which result in formation of defects. In this study, the microstructure change is investigated after solid state welding process to join the Al-Cu-Li sheets with optical and transmission electron microscopic analysis of precipitates.

Reliability Analysis of Rainwater Harvesting Systems in Southern Italy

Water scarcity is a current problem for many urban areas in the Mediterranean region due to the increasing water demand related to the population growth and the expansion of urban and industrialized areas. Climate change will intensify the pressure on water resources. Rainwater harvesting (RWH) may be an effective alternative water supply solution to face water scarcity. It has recently become a particularly important option in arid and semi-arid areas, mostly because of its many benefits and relative low costs. The present study aims to analyse the reliability of a RWH system installed to supply water for toilet flushing purpose with reference to a single-family house in a residential area of Sicily (Southern Italy). Historical water consumption data were analysed to obtain a flushing water demand pattern. A water balance simulation of the rainwater storage tank was performed, and the yield-after-spillage algorithm was used to define the tank release rule. The model's performance was evaluated using data from more than 100 different sites located throughout the Sicilian territory. This regional analysis provided results having practical applications, e.g. the identification of the optimal rainwater tank size and the annual system reliability curves as a function of mean annual precipitation. The uncertainty related to the regional model predictions was also assessed. Results showed that RWH systems can provide environmental and economic advantages in Sicily over traditional water supply methods. In particular, the regional analysis identified areas where the application of this system would be most effective.

Numerical modeling of self-pressurization and pressure control by a thermodynamic vent system in a cryogenic tank

This paper presents a numerical model of a system-level test bed—the multipurpose hydrogen test bed (MHTB) using the Generalized Fluid System Simulation Program (GFSSP). MHTB is representative in size and shape of a space transportation vehicle liquid hydrogen propellant tank, and ground-based testing was performed at NASA Marshall Space Flight Center (MSFC) to generate data for cryogenic storage. GFSSP is a finite volume-based network flow analysis software developed at MSFC and used for thermofluid analysis of propulsion systems. GFSSP has been used to model the self-pressurization and ullage pressure control by the Thermodynamic Vent System (TVS). A TVS typically includes a Joule–Thompson (J–T) expansion device, a two-phase heat exchanger (HEX), and a mixing pump and liquid injector to extract thermal energy from the tank without significant loss of liquid propellant. For the MHTB tank, the HEX and liquid injector are combined into a vertical spray bar assembly. Two GFSSP models (Self-Pressurization and TVS) were separately developed and tested and then integrated to simulate the entire system. The Self-Pressurization model consists of multiple ullage nodes, a propellant node, and solid nodes; it computes the heat transfer through multilayer insulation blankets and calculates heat and mass transfer between the ullage and liquid propellant and the ullage and tank wall. A TVS model calculates the flow through a J–T valve, HEX, and spray and vent systems. Two models are integrated by exchanging data through User Subroutines of both models. Results of the integrated models have been compared with MHTB test data at a 50% fill level. Satisfactory comparison was observed between tests and numerical predictions.

Super-fine powdered activated carbon (SPAC) for efficient removal of micropollutants from wastewater treatment plant effluent

In an effort to mitigate the discharge of micropollutants to surface waters, adsorption of micropollutants onto powdered activated carbon (PAC) after conventional wastewater treatment has been identified as a promising technology for enhanced removal of pharmaceuticals and pesticides from wastewater. We investigated the effectiveness of super-fine powdered activated carbon, SPAC, (ca. 1 μm mean particle diameter) in comparison to regular-sized PAC (17–37 μm mean diameter) for the optimization of micropollutant removal from wastewater. Adsorption isotherms and batch kinetic experiments were performed for 10 representative micropollutants (bezafibrate, benzotriazole, carbamazepine, diclofenac, gabapentin, mecoprop, metoprolol, ofloxacin, sulfamethoxazole and trimethoprim) onto three commercial PACs and their super-fine variants in carbonate buffer and in wastewater effluent. SPAC showed substantially faster adsorption kinetics of all micropollutants than conventional PAC, regardless of the micropollutant adsorption affinity and the solution matrix. The total adsorptive capacities of SPAC were similar to those of PAC for two of the three tested carbon materials, in all tested waters. However, in effluent wastewater, the presence of effluent organic matter adversely affected micropollutant removal, resulting in lower removal efficiencies especially for micropollutants with low affinity for adsorbent particles in comparison to pure water. In comparison to PAC, SPAC application resulted in up to two-fold enhanced dissolved organic carbon (DOC) removal from effluent wastewater. The more efficient adsorption process using SPAC translates into a reduction of contact time and contact tank size as well as reduced carbon dosing for a targeted micropollutant removal. In the tested effluent wastewater (5 mg/L DOC), the necessary dose to achieve 80% average removal of indicator micropollutants (benzotriazole, diclofenac, carbamazepine, mecoprop and sulfamethoxazole) ranged between 13 and 15 mg/L. These promising results warrant pilot-scale tests using super-fine PAC as an alternative to PAC for more efficient micropollutant removal.

Aircraft fuel measurement sensor optimal layout technology

It is very important for aircraft flight safety to accurately measure the remaining fuel in each fuel tank in real time. An aircraft fuel measurement sensor optimal layout method based on particle swarm optimization( PSO) was designed to improve aircraft fuel measurement accuracy. Firstly,the concept of the fuel entity was proposed,and two models were built including the complex wing fuel tank CAD model which had multi-chamber with inner clapboards and the fuel entity model in fuel tank. Secondly,the total fuel volumes of complex and irregular multi-chamber tanks were calculated at different aircraft attitudes based on the second development of Unigraphics NX( UG). Thirdly,the concept of the largest measurement range( LMR) of the aircraft fuel tanks was put forward,which was used as the goal to optimize the sensor layout. Finally,the boundary distance factor( BDF) was introduced to avoid settling the sensor too close to the fuel tank wall. The results show that the method can optimize the layout of several fuel sensors without being limited by the shape and size of the fuel tank,which can effectively avoid interference in the internal area of the tank,ensure fuel measurement continuity at different aircraft attitudes,and make the aircraft fuel measurable range reach a higher level.

Autonomous Adsorption Cooling—Driven by Heat Storage Collected from Solar Heat

This study investigates the performance of an adsorption chiller driven by thermal heat collected from solar collectors’ panels with heat storage. The heat is reserved in a storage tank and the reserved heat is used to drive the adsorption chiller. The investigation was carried on the climatic conditions of Dhaka, Bangladesh. Heat transfer fluid goes from the collectors to the adsorption cooling unit, then from the adsorption cooling unit to the storage tank. It is seen that heat storage is more effective than direct solar coupling; however, it requires more collectors, depending on the size of the storage tank. The analysis shows that cycle time is one of the most influential parameters for the solar-driven adsorption cooling system. It is seen that the size of the collector can be reduced if the proper cycle time is adjusted. The analysis also revealed that the system with 22 collectors (each of 2.415 m2) along with 1000 s cycle time provides better performance for the base run conditions. It is also seen that the solar-driven adsorption chiller with heat storage works well beyond the sunset time.

Climatic and spatial variability of potential rainwater savings for a large coastal city

Majority of the investigations on rainwater harvesting focused on sizing and potential water savings including studies proposing different methods of estimating rainwater tank outcomes. Several studies used monthly rainfall data to estimate rainwater tank outcomes. However, quantification using daily rainfall data will be much more accurate compared to using monthly rainfall data. A vast majority of works using daily rainfall data used daily water balance model for analysis. Again most of the studies using daily water balance model used historical rainfall data, calculated water savings for many years and then presented an average of all the calculated years’ total outcome(s). ‘Raintank Analyser’ is a tool, which uses the same methodology and widely used; used by the South Australian policy makers for producing relevant design charts. In contrast, eTank, a daily water balance model was developed to produce potential rainwater savings, augmented townwater supply, tank overflow, reliability and payback period for three distinct climate conditions (dry, average and wet years). This paper presents comparison of eTank calculated potential water savings with those calculated by ‘Raintank Analyser’ under similar conditions for a rainfall station in central Adelaide. In general, ‘Raintank Analyser’ produced water savings are very close to the eTank calculated water savings in average year. However, through the eTank produced potential water savings in dry and wet years, it is found that significant climatic variations exist. Magnitudes of climatic variations under different scenario are presented. Again, to assess spatial variability, three more rainfall stations from different regions of Adelaide metropolitan were selected. eTank was used to calculated potential water savings in three climatic conditions (dry, average and wet years) for various combinations of roof and tank sizes. Again it is found that depending input variable conditions (tank size, roof area and climate) significant spatial variations exist within some of the regions. Also, it is found that potential water savings not only depends on total rainfall amount of a particular area, but also on other input conditions; i.e. under similar conditions an area with lower annual rainfall may provide higher water savings due to rainfall pattern.