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Special Systems
Published in Carl Bozzuto, Boiler Operator's Handbook, 2021
The literature (Power Magazine among others) is constantly revealing new techniques and features of combined cycle plant operation. Their use is increasing. The percentage of generation coming from natural gas has increased from less than 20% in the early 2000s to nearly 40% two decades later. It is not just the availability of natural gas. It is also the fact that these plants are more efficient, converting more of the energy in the fuel to electricity than conventional boiler plants. An advanced steam plant has a full load efficiency of about 40%. A combined cycle plant (clean and new) will have a full load efficiency in the range of 52%−54% on a higher heating value (HHV) basis at International Standards Organization (ISO) conditions (59°F, sea level, 1 atmosphere, 60% relative humidity). The GT industry quotes their performance at ISO conditions because the performance of the GT is much more sensitive to site conditions than a steam plant. GTs also come in specific designs (like most engines). The GT industry also uses the lower heating value (LHV) to quote their equipment performance. That is because a higher efficiency number can be calculated using LHV and ignoring the water vapor that is produced with the combustion of natural gas. Thus, industry advertisements will claim efficiency numbers of nearly 60%–61%. The wise operator will read the fine print. That figure is based on LHV and ISO conditions (clean and new). On a hot day, with a higher ambient temperature and higher relative humidity at even a modestly higher altitude, the performance of the GT will fall off significantly (6%–10% drop in efficiency).
Modern Power Systems
Published in Dale R. Patrick, Stephen W. Fardo, Brian W. Fardo, Electrical Power Systems Technology, 2021
Dale R. Patrick, Stephen W. Fardo, Brian W. Fardo
Since the majority of electrical power produced today is from coal-fired systems, we will discuss the basic operation of this type of system. In a steam plant that produces electrical power, most of the operations are used for rotating the steam turbine. Remember that in any steam plant, heat must be produced. This heat produces steam, which moves the steam turbine, which produces a rotary motion, and which finally produces electrical power. Figure 4.3 shows the layout of a typical coal-fired electrical power plant. Note that it is located near a river so that cooling water can be easily provided. The water is also used to produce steam to operate the steam turbine that rotates the generator unit. A cross-section of a coal-fired power plant is shown in Figure 4.4.
Modern Power Systems
Published in Stephen W. Fardo, Dale R. Patrick, Electrical Power Systems Technology, 2020
Stephen W. Fardo, Dale R. Patrick
Since the majority of electrical power produced today is from coal-fired systems, we will discuss the basic operation of this type of system. In a steam plant that produces electrical power, most of the operations are used for rotating the steam turbine. Remember that in any steam plant, heat must be produced. This heat produces steam, which moves the steam turbine, which produces a rotary motion, which finally produces electrical power. Figure 4-2 shows the layout of a typical coal-fired electrical power plant. Notice that it is located near a river, so that cooling water can be easily provided. The water is also used to produce steam to operate the steam turbine that rotates the generator unit. A cross-section of a coal-fired power plant is shown in Figure 4-3.
Building control virtual test bed and functional mock-up interface standard: comparison in the context of campus energy modelling and control
Published in Journal of Building Performance Simulation, 2020
Mohammad Hassan Fathollahzadeh, Paulo Cesar Tabares-Velasco
While most campus-level studies implement demand profiles from prototype buildings or oversimplified physics-based models, it is important to use actual building models and energy use for a significant number of reasons such as accurate peak load analysis. Because authors have access to building energy performance data and constructions drawing, this study uses the Colorado School of Mines’ (hereafter referred to as Mines) campus as the proof-of-concept demonstration. Mines is located in Golden (ASHRAE climate zone 5B (Baechler et al. 2010)), Colorado, has about 6,300 enrolled students, 80 buildings, and covers approximately 500 acres (Oldfield 2019). Mines uses two main energy commodities, electricity and natural gas, which are provided by the local utility. Electricity is the main energy cost driver for the campus with a peak electrical demand of approximately 7.23 MW that took place in September 2019. It has a central natural gas-fired steam plant used for space heating, domestic hot water, and lab equipment on the campus. Cooling is provided via four chiller plants producing chilled water for space conditioning or cooling process. Figure 3 shows campus chilled water loops: loop 4 (Green Center), 5 (Alderson Hall), 6 (Brown Hall) and 7 (Arthur Lakes library). This study focuses on loop 6 and models buildings in this loop as it has the highest number of buildings, energy cost contribution (around 20%), and anticipation for new buildings construction.
Deterioration effects on the performance of a steam plant for the waste heat recovery from a marine diesel engine
Published in Ships and Offshore Structures, 2019
Marco Altosole, Ugo Campora, Michele Laviola, Raphael Zaccone
In light of the analysis carried out through this study, the following main conclusions can be drawn: The degradation of the evaporator presents the most significant influence on the combined plant and cogeneration efficiency. Although the degradation of this component increases both the Rankine cycle efficiency and the ST delivered power, the associated DE back-pressure increase reduces the DE efficiency.the steam turbine blades erosion can affect significantly the overall combined and cogeneration plant efficiency, if compared to the ST blades fouling.the condenser degradation is responsible for reducing the Rankine cycle maximum efficiency and ST delivered power.the individual degradation of all the other WHR steam plant components has a minor effect on the DE-WHR steam plant overall performance.
An Innovative variable layout steam plant for waste heat recovery from marine dual-fuel engines
Published in Ships and Offshore Structures, 2023
Marco Altosole, Ugo Campora, Luigia Mocerino, Raphael Zaccone
Once the geometric and functional characteristics of the WHR steam plant components have been defined, the equations reported in section 3 can be rearranged according to the geometric dimensions of the heat exchangers and the performance characteristics of the steam turbine and pumps. The single steam pressure WHR plant functional and performance parameters can then be determined, including, for instance, the steam and gas pressure, the temperature and mass flow rate in the various plant components, the efficiencies of the steam turbine and pumps. In this paper, the optimisation procedure refers to the engine running in both NG and diesel modes and NCR conditions, where the mass flow and temperature of the engine exhaust gas are assumed according to Figure 3.