scholarly journals Design and Performance Analysis of New Ultra-Supercritical Double Reheat Coal-Fired Power Generation Systems

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 238
Author(s):  
Ming Yang ◽  
Liqiang Duan ◽  
Yongjing Tong
Keyword(s):  
Heat Transfer ◽  
Power Generation ◽  
Reference System ◽  
Simulation Software ◽  
Coal Consumption ◽  
System 2 ◽  
System 1 ◽  
Power Generation Systems ◽  
New System ◽  
Better Than

In order to solve the existing problems of large mean heat transfer temperature differences of regenerative air heaters and high superheat degrees of regenerative extraction steam in double reheat coal-fired power generation systems, two new design schemes of ultra-supercritical double reheat cycles are proposed, which can realize the deep boiler-turbine coupling among the heat transfer processes of air, feeding water and regeneration extraction steam on the base of the principle of energy level matching. A typical 1000 MW ultra-supercritical double reheat cycle system is selected as the reference system and the overall system model is built by using the Ebsilon simulation software. The performances of two new systems are analyzed by using both the exergy method and energy equilibrium method. The results show that net output powers of both new systems 1 and 2 increase by 6.38 MW and 6.93 MW, respectively, and the standard coal consumptions of power generation decrease by 1.65 g/kWh and 1.79 g/kWh, respectively. The off-design performances of new systems and the reference system are analyzed, and the results show that performances of two new systems are better than that of the reference system. The system flow of the new system 2 is more complex compared with that of the new system 1. Generally speaking, the performance of new system 1 is better than that of new system 2. On the basis of new system 1, new system 3 is further optimized and its full operating condition performance characteristics are analyzed. The standard coal consumption rate of new system 3 is reduced about 1 g/kWh at higher load, and around 0.2 g/kWh at low load.

Synergetic Utilization of Coal and Industrial Waste Heat in Power Generation System

2013 ◽  
Vol 724-725 ◽  
pp. 990-998
Author(s):  
Zhen Chen ◽  
Wei Dou Ni
Keyword(s):  
Power Generation ◽  
Industrial Waste ◽  
Waste Heat ◽  
Generation System ◽  
Coal Consumption ◽  
Power Generation System ◽  
Industrial Waste Heat ◽  
Synergetic System ◽  
Power Generation Systems ◽  
Heating Mode

Coal and industrial waste heat synergetic utilization power generation system (the synergetic system) is proposed according to the energy cascade utilization principle. The industrial waste heat is used for feedwater heating of coal-fired power generation system to substitute steam extraction from steam turbine. The thermal performance of stand-alone waste heat power generation, stand-alone coal-fired power generation, and synergetic systems were studied, to compare the power generation capability of each system using heat balance method. The results show that the power generation capability of synergetic power generation system is larger than that of the two stand-alone systems. The equivalent and same grade waste heat synergized with higher-parameter, larger-capacity coal-fired power generation systems can generate more electricity than with the low-parameter ones; the high-parameter waste heat synergized with the higher-parameter and larger-capacity power generation systems can reach larger power generation capability. The multi-energy synergetic heating mode can greatly improve the comprehensive energy efficiency and reduce the coal consumption compared with the stand-alone energy heating mode.

Evaluation of Atmospheric Fields from the ECMWF Seasonal Forecasts over a 15-Year Period

2005 ◽  
Vol 18 (16) ◽  
pp. 3250-3269 ◽  
Author(s):  
Geert Jan van Oldenborgh ◽  
Magdalena A. Balmaseda ◽  
Laura Ferranti ◽  
Timothy N. Stockdale ◽  
David L. T. Anderson
Keyword(s):  
Teleconnection Pattern ◽  
Seasonal Forecasts ◽  
Sea Level Pressure ◽  
Weather Forecasts ◽  
Enso Teleconnections ◽  
Medium Range ◽  
Data Points ◽  
System 2 ◽  
System 1 ◽  
Better Than

Abstract Since 1997, the European Centre for Medium-Range Weather Forecasts (ECMWF) has made seasonal forecasts with ensembles of a coupled ocean–atmosphere model, System-1 (S1). In January 2002, a new version, System-2 (S2), was introduced. For the calibration of these models, hindcasts have been performed starting in 1987, so that 15 yr of hindcasts and forecasts are now available for verification. The main cause of seasonal predictability is El Niño and La Niña perturbing the average weather in many regions and seasons throughout the world. As a baseline to compare the dynamical models with, a set of simple statistical models (STAT) is constructed. These are based on persistence and a lagged regression with the first few EOFs of SST from 1901 to 1986 wherever the correlations are significant. The first EOF corresponds to ENSO, and the second corresponds to decadal ENSO. The temperature model uses one EOF, the sea level pressure (SLP) model uses five EOFs, and the precipitation model uses two EOFs but excludes persistence. As the number of verification data points is very low (15), the simplest measure of skill is used: the correlation coefficient of the ensemble mean. To further reduce the sampling uncertainties, we restrict ourselves to areas and seasons of known ENSO teleconnections. The dynamical ECMWF models show better skill in 2-m temperature forecasts over sea and the tropical land areas than STAT, but the modeled ENSO teleconnection pattern to North America is shifted relative to observations, leading to little pointwise skill. Precipitation forecasts of the ECMWF models are very good, better than those of the statistical model, in southeast Asia, the equatorial Pacific, and the Americas in December–February. In March–May the skill is lower. Overall, S1 (S2) shows better skill than STAT at lead time of 2 months in 29 (32) out of 40 regions and seasons of known ENSO teleconnections.

scholarly journals Numerical Evaluation of a HVAC System Based on a High-Performance Heat Transfer Fluid

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3298
Author(s):  
Gianpiero Colangelo ◽  
Brenda Raho ◽  
Marco Milanese ◽  
Arturo de Risi
Keyword(s):  
Heat Transfer ◽  
High Performance ◽  
Cooling System ◽  
Electrical Energy ◽  
Simulation Software ◽  
Heat Transfer Fluid ◽  
Hvac System ◽  
Dynamic Simulations ◽  
Heating And Cooling ◽  
The University

Nanofluids have great potential to improve the heat transfer properties of liquids, as demonstrated by recent studies. This paper presents a novel idea of utilizing nanofluid. It analyzes the performance of a HVAC (Heating Ventilation Air Conditioning) system using a high-performance heat transfer fluid (water-glycol nanofluid with nanoparticles of Al2O3), in the university campus of Lecce, Italy. The work describes the dynamic model of the building and its heating and cooling system, realized through the simulation software TRNSYS 17. The use of heat transfer fluid inseminated by nanoparticles in a real HVAC system is an innovative application that is difficult to find in the scientific literature so far. This work focuses on comparing the efficiency of the system working with a traditional water-glycol mixture with the same system that uses Al2O3-nanofluid. The results obtained by means of the dynamic simulations have confirmed what theoretically assumed, indicating the working conditions of the HVAC system that lead to lower operating costs and higher COP and EER, guaranteeing the optimal conditions of thermo-hygrometric comfort inside the building. Finally, the results showed that the use of a nanofluid based on water-glycol mixture and alumina increases the efficiency about 10% and at the same time reduces the electrical energy consumption of the HVAC system.

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