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Storage Vessel (storage + vessel)
Selected AbstractsCold storage with ice slurriesINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 3 2008P. W. Egolf Abstract The storage of ,cold' with ice slurries,a special type of thermally multi-functional fluids or phase change slurries (PCS),is discussed. At first an example of a calculation of a thermal energy storage tank in an ice slurry system with a peak load demand is presented. Then a new concept of ice slurry storage without mixing is introduced. It leads to ice particle stratification and front propagation in the storage vessel. The stratification of ice particles in ice slurry is theoretically described by multi-component multi-phase fluid dynamics. The resulting stratification process is calculated and front propagation times are compared with experimental results; they compare fairly well. Copyright © 2007 John Wiley & Sons, Ltd. [source] Demand side management for water heating installations in South African commercial buildingsINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 4 2001P. G. Rousseau Abstract The largest percentage of the sanitary hot water used in South African buildings is heated by means of direct electrical resistance heaters. This is one of the major contributing factors of the undesirable high morning and afternoon peaks imposed on the national electricity supply grid. Water heating therefore continues to be of concern to ESKOM, the country's only electrical utility company. The so-called in-line water heating system design methodology was developed to address this problem. This paper investigates the potential impact of in-line systems on the national peak electrical demand. A computer simulation model was developed that combines a deterministic mathematical model with a statistical approach in order to predict the diversity factors associated with both the existing and in-line design methodologies. A study was also conducted to estimate the total installed water heating capacity in the national commercial building sector. This figure can be combined with the simulated diversity factor to determine the peak electrical demand. The deterministic model includes the detailed simulation of the hot water storage vessel, the electrical heater and the system control algorithm. The mathematical model for the storage vessel is based on an electrical analogue approach that includes the effects of conduction as well as forced and natural convection. This model was verified extensively with the aid of laboratory measurements and compared with existing storage vessel models. It was found that the new storage vessel model could predict the supply temperature within 2 per cent for a system configuration with the heater in parallel outside the reservoir and within 12 per cent for a configuration with the heater situated inside the reservoir. This compares favourably with existing models found in the literature. The complete simulation based on the statistical approach showed that extensive application of the new design methodology could result in a reduction of approximately 75 MW in the total maximum peak demand imposed on the electricity supply grid in wintertime. This is 58 per cent of the current peak demand due to commercial water heating and 12.5 per cent of the peak load reduction target set by ESKOM until the year 2015. Copyright © 2001 John Wiley & Sons, Ltd. [source] The rotational molding of a thermotropic liquid crystalline polymerPOLYMER ENGINEERING & SCIENCE, Issue 3 2005Eric Scribben Thermotropic liquid crystalline polymers (TLCPs) exhibit a number of mechanical and physical properties such as excellent chemical resistance, low permeability, low coefficient of thermal expansion, high tensile strength and modulus, and good impact resistance, which make them desirable as a rotationally molded storage vessel. However, there are no reports in the technical literature of the successful rotational molding of TLCPs. In this article, conditions are identified that lead to the successful rotational molding of a TLCP, Vectra B 950. First, a technique was developed to produce particles suitable for rotational molding because TLCPs cannot be ground into a free-flowing powder. Second, because the viscosity at low shear rates can be detrimental to the sintering process, coalescence experiments with isolated particles were carried out to determine the thermal and environmental conditions at which sintering should occur. These conditions were then applied to static sintering experiments to determine whether coalescence and densification of the bulk powder would occur. Finally, the powders were successfully rotationally molded into tubular structures in a single axis, lab-scale device. The density of the molded structure was essentially equivalent to the material density and the tensile strength and modulus were approximately 18 MPa and 2 GPa, respectively. POLYM. ENG. SCI., 45:410,423, 2005. © 2005 Society of Plastics Engineers [source] A unified model of property integration for batch and continuous processesAICHE JOURNAL, Issue 7 2010Cheng-Liang Chen Abstract This article aims to present a general model for synthesis of property-based resource conservation networks. The proposed model is applicable to batch and continuous processes. Therein, the process systems are characterized by properties instead of composition that is found in most published works to date in the area of resource conservation. By treating continuous process as a special case of batch processes, both kinds of operations can be optimized with a unified model that is developed on the basis of a superstructure. The overall framework of property network is adopted, where material reuse/recycle, interception, and waste treatment are all taken into consideration. Apart from direct reuse/recycle, interception devices are employed to improve stream properties for further recovery, whereas effluent treatment is needed for compliance with environmental discharge limits. In addition, storage vessels are employed in batch processes to override intrinsic time constraint. Four case studies are solved to illustrate the proposed approach. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Groundwater Banking in Aquifers that Interact With Surface Water: Aquifer Response Functions and Double-Entry Accounting,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 6 2009Bryce A. Contor Contor, Bryce A., 2009. Groundwater Banking in Aquifers That Interact With Surface Water: Aquifer Response Functions and Double-Entry Accounting. Journal of the American Water Resources Association (JAWRA) 45(6):1465-1474. Abstract:, Increasing worldwide demands for water call for mechanisms to facilitate storage of seasonal supplies and mechanisms to facilitate reallocation of water. Markets are economically efficient reallocation and incentive mechanisms when market conditions prevail, but special hydrologic and administrative conditions of water use and allocation interfere with required market conditions. Water banking in general can bring market forces to bear on water storage and reallocation, improving economic efficiency and therefore the welfare of society as a whole. Groundwater banking can utilize advantages of aquifers as storage vessels with vast capacity, low construction cost, and protection of stored water. For groundwater banking in aquifers that interact with surface water, an accounting system is needed that addresses the depletion of stored volumes of water as water migrates to surface water. Constructing such a system requires integration of hydrologic, economic, and legal principles with principles of financial accounting. Simple mass-balance accounting, even with allowances for depletion, is not adequate in these aquifers. Aquifer response functions are mathematical descriptions of the impact that aquifer pumping or recharge events have upon hydraulically connected surface water bodies. Double-entry accounting is a financial accounting methodology for tracking asset inventories and ownership claims upon assets. The powerful innovation of linking aquifer response functions with double-entry accounting technologies allows application of groundwater banking to aquifers where deposits can be depleted by migration to hydraulically connected surface water. It honors the hydrologic realities of groundwater/surface water interaction, the legal requirements of prior appropriation water law, and the economic requirements for equitable and efficient allocation of resources. 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