16 research outputs found
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Computer Simulation of Scale Formation
This paper summarizes results of recent analyses performed by Battelle-Northwest in EPRI project RP 653-3: Computer Simulation of Scaling in Geothermal Systems. The results reported here are drawn primarily from case evaluations performed over the 12 months since the preceding EPRI Geothermal Symposium held in Monterey in June 1979. The present project is a continuation of a previous project designated RP 653-1. The ultimate objective of research performed in this project is to develop analytical tools (computer codes) and the supporting thermophysical and chemical data base that can be used to predict scaling and corrosion in geothermal power generating systems
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Physical modeling of joule heated ceramic glass melters for high level waste immobilization
This study developed physical modeling techniques and apparatus suitable for experimental analysis of joule heated ceramic glass melters designed for immobilizing high level waste. The physical modeling experiments can give qualitative insight into the design and operation of prototype furnaces and, if properly verified with prototype data, the physical models could be used for quantitative analysis of specific furnaces. Based on evaluation of the results of this study, it is recommended that the following actions and investigations be undertaken: It was not shown that the isothermal boundary conditions imposed by this study established prototypic heat losses through the boundaries of the model. Prototype wall temperatures and heat fluxes should be measured to provide better verification of the accuracy of the physical model. The VECTRA computer code is a two-dimensional analytical model. Physical model runs which are isothermal in the Y direction should be made to provide two-dimensional data for more direct comparison to the VECTRA predictions. The ability of the physical model to accurately predict prototype operating conditions should be proven before the model can become a reliable design tool. This will require significantly more prototype operating and glass property data than were available at the time of this study. A complete set of measurements covering power input, heat balances, wall temperatures, glass temperatures, and glass properties should be attempted for at least one prototype run. The information could be used to verify both physical and analytical models. Particle settling and/or sludge buildup should be studied directly by observing the accumulation of the appropriate size and density particles during feeding in the physical model. New designs should be formulated and modeled to minimize the potential problems with melter operation identifed by this study
Dry/wet performance of a plate-fin air-cooled heat exchanger with continuous corrugated fins
The performance and operating characteristics of a plate-fin heat exchanger in dry/wet or deluge operations was experimentally determined. Development of the deluge heat/mass transfer model continued. The experiments were conducted in a specially-designed wind tunnel at the PNL. Air that was first heated and humidified to specified conditions was circulated at a controlled rate through a 2 ft x 6 ft heat exchanger module. The heat exchanger used in the tests was a wavy surface, plate fin on tube configuration. Hot water was circulated through the tubes at high flow rates to maintain an essentially isothermal condition on the tube side. Deionized water sprayed on the top of the vertically oriented plate fins was collected at the bottom of the core and recirculated. Instrumentation was provided for measurement of flow rates and thermodynamic conditions in the air, in the core circulation water, and in the deluge water. Measurements of the air side pressure drop and heat rejection rate were made as a function of air flow rate, air inlet temperature and humidity, deluge water flow rate, and the core inclination from the vertical. An overall heat transfer coefficient and an effective deluge film convective coefficient was determined. The deluge model, for predicting heat transfer from a wet finned heat exchanger was further developed and refined, and a major extension of the model was formulated that permits simultaneous calculation of both the heat transfer and evaporation rates from the wetted surface. The experiments showed an increase in the heat rejection rate due to wetting, accompanied by a proportional increase in the air side pressure drop. For operation at the same air side pressure drop, the enhancement ratio Q/sub w//Q/sub d/ varied between 2 and 5 for the conditions tested. Thus, the potential enhancement of heat transfer due to wetting can be substantial
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Benefit/cost comparisons of SMES in system-specific application scenarios
The inherently high storage efficiency, instantaneous dispatch capability and multi-function uses of superconducting magnetic energy storage (SMES) are attributes that give it the potential for widespread application in the electric utility industry. Opportunities appear to exist where SMES at a given location could provide multiple benefits either simultaneously or sequentially as system conditions dictate. These benefits, including diurnal storage and system stability and dynamic control enhancement, increase the application potential of SMES to a larger number of opportunities than might be justified by the value of its diurnal storage capability alone. However, the benefits an individual utility may realize from SMES applications are strongly influenced by the characteristics of the utility system, the location of the SMES unit and the timing of its installation in the system. Such benefits are typically not evaluated adequately in generic studies. This paper summarizes results of case studies performed by Pacific Northwest Laboratory (PNL) with funding provided by the Bonneville Power Administration (BPA) and the Electric Power Research Institute (EPRI). The derivation of SMES benefits and costs are described and benefit/cost (B/C) ratios are compared in system-specific scenarios of interest to BPA. Results of using the DYNASTORE production cost model show the sensitivity of B/C ratios to SMES capacity and power and to the forecast system load. Intermediate-size SMES applications which primarily provide system stability and dynamic control enhancement are reviewed. The potential for SMES to levelize the output of a wind energy complex is also assessed. Most of the cases show SMES to provide a positive net benefit with the additional, sometimes surprising indication, that B/C ratios and net present worth of intermediate-size units can exceed those of larger systems