Economical analyses of build-operate-transfer model in establishing alternative power plants

2007 ◽  
Vol 48 (1) ◽  
pp. 234-241 ◽  
Author(s):  
Zehra Yumurtaci ◽  
Hasan Hüseyin Erdem
Keyword(s):  
Power Plants ◽  
Transfer Model ◽  
Alternative Power

Deviation Analysis on Flow and Heat Transfer Model of Large Air-Cooled Steam Condenser Unit

2013 ◽  
Vol 860-863 ◽  
pp. 656-662
Author(s):  
Yi Lv ◽  
Hui Zhang ◽  
Yu Jin Yue ◽  
Li Jun Yang ◽  
Xiao Dong Zhang
Keyword(s):  
Heat Transfer ◽  
Power Plants ◽  
Thermal Power ◽  
Large Diameter ◽  
Axial Flow ◽  
Internal Flow ◽  
Ambient Air ◽  
Transfer Model ◽  
Deviation Analysis ◽  
Flow And Heat Transfer

Many power plants adopt air-cooled condensers (ACC) with finned tubes, using ambient air to condense turbine exhaust steam. Each condenser unit is mainly composed of two heat transfer surfaces like A and large diameter axial flow fans driving air. In the study of environmental wind effects, etc, due to the condenser unit size is bigger, it is necessary to simplify the condenser unit internal flow and heat transfer calculation, but the deviations introduced by these simplifies failed to get enough attention. In view of one condenser unit, three kinds of flow and heat tansfer combinated model were respectively investigated. A computational fluid dynamics software (CFD) is used to solve the problem.Research priority is analyzing the deviations of internal flow and heat transfer features in the condenser unit according to the extracted datum. The study gives some useful informatin to the design of a thermal power plant with an ACC system.

Novel Evaporator Geometries Based on Entrance-Length Flow-Paths for Geothermal Binary Power Plants

2016 ◽  
Author(s):  
Adrian S. Sabau ◽  
Ali H. Nejad ◽  
James W. Klett ◽  
Adrian Bejan ◽  
Kivanc Ekici
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Power Plants ◽  
Cost Model ◽  
Operating Conditions ◽  
Transfer Model ◽  
Length Scale ◽  
Entrance Length ◽  
Scale Levels

In this paper, a novel geometry is proposed for evaporators that are used in Organic Rankine Cycles. The proposed geometry consists of employing successive plenums at several length-scale levels, creating a multi-scale heat exchanger. The channels at the lowest length-scale levels were considered to have their length given by the thermal entrance-length. Numerical simulations based on turbulent flow correlations for supercritical R134a and water were used to obtain performance indicators for new heat exchangers and baseline heat exchangers. The relationship between the size of the channels at one level, k, with respect to the size of the channels at the next level, k + 1, is based on generalization of the “Murray’s law.” In order to account for the variation of the temperature and heat transfer coefficient in the entrance region, a heat transfer model was developed. The variation of the brine and refrigerant temperatures along each pipe was considered. Using the data on pumping power and weight of metal structures, including that of all the plenums and piping, the total present cost was evaluated using a cost model for shell-and-tube heat exchangers. In addition to the total present cost, the data on overall thermal resistance is also used in identifying optimal heat exchanger configurations. The main design variables include: tube arrangement, number of channels fed from plenum, and number of rows in the tube bank seen by the outside fluid. In order to assess the potential improvement of the new evaporator designs, baseline evaporators were designed. The baseline evaporator designs include long tubes of the same diameter as those of the lowest length-scale levels, placed between one inlet and one outlet. The baseline evaporator designs were created from the new evaporator designs by simply removing most of the internal plenums employing tubes much longer than their entrance length, as they would currently be used. Consistent with geothermal applications, the performance of new heat exchanger designs was compared to that of baseline heat exchanger designs at the same flow rates. For some operating conditions it was found that the new heat exchangers outperform their corresponding baseline heat exchangers.

scholarly journals Simulation of 20 kV Biomass Power Plant Interconnection System

2019 ◽  
Vol 125 ◽  
pp. 14001
Author(s):  
Adri Senen ◽  
Isworo Pujotomo ◽  
Yoakim Simamora
Keyword(s):  
Power Plant ◽  
Power Flow ◽  
Power Plants ◽  
Voltage Drop ◽  
Short Circuit ◽  
Power Losses ◽  
Before And After ◽  
Alternative Power ◽  
Biomass Power Plant ◽  
Short Circuit Currents

The need for new plants is needed to balance the demand for high electricity. To anticipate this, it is necessary to accelerate the achievement of the level of utilization of new and renewable energy (EBT) in the energy mix for electricity supply by encouraging the use of energy from water, biomass, solar, wind to electricity. The Biomass Power Plant (PLTBm) is one of the environmentally friendly alternative power plants that produce electricity and heat by burning biomass in boilers in this case from wood waste from furniture and old rubber trees. The Interconnection System will be implemented in this PLTBm, where interconnection with the existing 20 kV system will be carried out. Research carried out includes power flow, voltage drop, losses, and short circuit. By conducting this study, it can be seen the profile of the overall system operation before and after this interconnection. The simulation results show that the PLTBm connected to the nearest feeder point from the generator is the best choice in terms of making the system voltage better between 19.1 kV and 20.17 kV. Power losses range from 439 kW and 5005.4 Kvar as well as short circuit currents, namely 13.73 KA.

Deriving cloud information from all-sky images for intra-hour PV nowcasting

2021 ◽  
Author(s):  
Philipp Gregor ◽  
Tobias Zinner ◽  
Bernhard Mayer ◽  
Josef Schreder
Keyword(s):  
Power Plant ◽  
Radiative Transfer ◽  
Power Plants ◽  
Reference Data ◽  
Weather Prediction ◽  
Energy Output ◽  
Cloud Base ◽  
Transfer Model ◽  
Weather Situation ◽  
Cloud Base Height

<p>Energy output from photovoltaics (PV) strongly depends on the respective weather situation. To ensure continuous energy availability in power grids with large PV contribution, flexibly manageable power plants have to compensate for variations in PV power production. Within the project NETFLEX, an intra-hour irradiance now-casting algorithm is developed as a basis for a PV power forecast used for management of a combined PV / biogas power plant.<!-- a combined PV / biogas power plant? --></p><p>The now-casting algorithm is designed around a cloud representation in a simplistic 2D advection model, which is updated with currently measured data and which projects cloud situations up to 15 minutes into the future. Main input to the model are images captured by two CMS Schreder all-sky imagers (ASI) installed at the PV plant in locations separated by about 530m. Captured images are processed to extract cloud masks, cloud base heights and cloud movement. To obtain cloud masks, ratios of red and blue channels as well as saturation and brightness are compared to reference data from a clearsky library.<!-- Kommt mir hier etwas zu ausführlich vor. Lieber etwas wie?: To obtain a cloud mask, ratios of red and blue channels as well as saturation and brightness are compared to reference data from a clearsky library. --><!-- --> This library is composed from synthetic clearsky data computed by the radiative transfer model <em>libRadtran</em> (Mayer and Kylling, 2005), which are processed to resemble imager geometry and optics. The creation of synthetic references allows for any desired sun position and aerosol condition. Simultaneously captured images of both cameras are evaluated and corresponding pixels are matched. Exact calibration of the imager geometry then allows for cloud base height derivation using the method of miss-pointing vectors (Kölling et al., 2019). Consecutive images are evaluated <!-- “Per imager”  “for each camera” -->for each ASI to estimate horizontal cloud motion by matching corresponding pixels. All cloud information computed from ASI images is assimilated into the 2D model as a base for cloud field predictions with information about cloud position, base height and velocity. The model-centered approach allows for flexible integration of additional data sources, e.g. satellite imagery and numerical weather prediction data.</p><p>Validation of image evaluation methods and now-casting model is done using synthetic all-sky images of LES cloud fields<!-- Könnte hier noch etwas von “promising results“ sagen. Aber das ist vermutlich klar und wahrscheinlich auch auf der Konferenz deutlicher aufzuführen. -->. Additionally, cloud base height from a ceilometer as well as global and direct integrated solar irradiance were measured on site of the PV power plant. This also allows for validation on real world cases.<br><br></p><p><em>Literature:</em></p><p>Kölling, T., Zinner, T., and Mayer, B.: <em>Aircraft-based stereographic reconstruction of 3-D cloud geometry</em>, Atmos. Meas. Tech., 12, 1155–1166, 2019.</p><p>Mayer, B. and Kylling, A.: <em>Technical note: The libRadtran software package for radiative transfer calculations - description and examples of use</em>, Atmos. Chem. Phys., 5, 1855–1877, 2005.</p>

Thermal Loading Failure Analysis of Molten Pool in the Reactor Vessel

2010 ◽  
Author(s):  
Xiao Yang ◽  
Yanhua Yang ◽  
Bo Kuang ◽  
Xiaoliang Fu
Keyword(s):  
Heat Flux ◽  
Molten Pool ◽  
Nuclear Power ◽  
Power Plants ◽  
Thermal Loading ◽  
Success Probability ◽  
Local Heat ◽  
Reactor Vessel ◽  
Transfer Model ◽  
Severe Accidents

Uncertainties are addressed in the special context of assessing and managing risks from rare, severe-consequence hazards. Risk Oriented Accident Analysis Methodology (ROAAM) is used to analyze uncertainties during severe accidents analysis in nuclear power plants. In-vessel Retention (IVR) is one of the mitigations for severe accidents which will cause core damage. By external reactor vessel cooling (ERVC), the integrity of the reactor vessel is preserved. The success criterion for IVR is the local heat flux on the wall of lower head is less than the critical heat flux (CHF). This paper analyzes the uncertain parameters which decide the mitigation to be successful or fail. Two bounding structures and 4 molten pool steady states are defined. And the success probability of IVR is evaluated with a molten pool heat transfer model. Then the effectiveness of IVR-ERVC under the two bounding structures is evaluated.

scholarly journals Development of Instrument Transmitter Protecting Device against High-Temperature Condition during Severe Accidents

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Min Yoo ◽  
Sung Min Shin ◽  
Hyun Gook Kang
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Nuclear Power ◽  
Power Plants ◽  
Severe Accident ◽  
Transfer Model ◽  
Potential Threat ◽  
Severe Accidents ◽  
Development Of Instrument ◽  
Novel Concept

Reliable information through instrumentation systems is essential in mitigating severe accidents such as the one that occurred at the Fukushima Daiichi nuclear power plant. There are five elements which might pose a potential threat to the reliability of parameter detection at nuclear power plants during a severe accident: high temperature, high pressure, high humidity, high radiation, and missiles generated during the evolution of a severe accident. Of these, high temperature apparently poses the most serious threat, since thin shielding can get rid of pressure, humidity, radiation (specifically, alpha and beta radiations), and missile effects. In view of this fact, our study focused on designing an instrument transmitter protecting device that can eliminate the high-temperature effect on transmitters to maintain their functional integrity. We present herein a novel concept for designing such a device in terms of heat transfer model that takes into account various heat transfer mechanisms associated with the device.

Numerical Analysis of Heat Loss From a Parabolic Trough Absorber Tube With Active Vacuum System

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Matthew Roesle ◽  
Volkan Coskun ◽  
Aldo Steinfeld
Keyword(s):  
Heat Loss ◽  
Power Plants ◽  
Rarefied Gas ◽  
Radiation Heat Transfer ◽  
Vacuum System ◽  
Transfer Model ◽  
Parabolic Trough ◽  
Annular Gap ◽  
Continuous Vacuum ◽  
Vacuum Jacket

In current designs of parabolic trough collectors for concentrating solar power plants, the absorber tube is manufactured in segments that are individually insulated with glass vacuum jackets. During the lifetime of a power plant, some segments lose vacuum and thereafter suffer from significant convective heat loss. An alternative to this design is to use a vacuum pump to actively maintain low pressure in a long section of absorber with a continuous vacuum jacket. A detailed thermal model of such a configuration is needed to inform design efforts for such a receiver. This paper describes a combined conduction, convection, and radiation heat transfer model for a receiver that includes the effects of nonuniform solar flux on the absorber tube and vacuum jacket as well as detailed analysis of conduction through the rarefied gas in the annular gap inside the vacuum jacket. The model is implemented in commercial CFD software coupled to a Monte Carlo ray-tracing code. The results of simulations performed for a two-dimensional cross-section of a receiver are reported for various conditions. The parameters for the model are chosen to match the current generation of parabolic trough receivers, and the simulation results correspond well with experimental measurements.

Alternative Power Plants for Automotive Purposes

1972 ◽  
Vol 186 (1) ◽  
pp. 125-140 ◽  
Author(s):  
E. M. Estes
Keyword(s):  
United States ◽  
Carbon Monoxide ◽  
Nitrogen Oxides ◽  
Power Plants ◽  
The United States ◽  
Considerable Progress ◽  
General Motors ◽  
Distant Future ◽  
Alternative Power ◽  
Additional Reduction

In the last 20 years, automotive engineers in the United States have made considerable progress in emission control. Hydrocarbons, carbon monoxide and nitrogen oxides have been reduced substantially. Despite this, new legislation passed in 1970 requires an additional reduction below the present levels by 1975–1976, and this lecture discusses this new engineering challenge. General Motors’ latest progress with alternative power plants and their relative feasibility in both the near and more distant future is discussed.

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