Comparison of Detailed and Simplified Optimization Approaches for the Performance Simulation of Cogeneration Plants

2009 ◽  
Author(s):  
Stefano Campanari ◽  
Giampaolo Manzolini ◽  
Paolo Silva
Keyword(s):  
Gas Turbines ◽  
Management Strategies ◽  
Primary Energy ◽  
Pollutant Emissions ◽  
Computational Time ◽  
Plant Management ◽  
Small Scale ◽  
Optimization Strategy ◽  
Detailed Model ◽  
Partial Load

It is well known that cogeneration can be an effective energy-saving solution, able to achieve relevant reductions in primary energy consumption and pollutant emissions. Generally speaking, obtaining best performances from a cogeneration plant requires a proper design and a careful management, aiming to maximize the plant energy and economic savings. Solving the issue of optimization may require a dedicated simulation tool when the CHP plant faces variable loads (both electrical, thermal and in some cases cooling loads) and electricity tariffs, or significantly changes its efficiency at partial load, or integrates a heat storage which allows to extend the possible plant management strategies. In all these cases, the optimization results may not be easy predictable. However, in other cases also simpler and faster approaches may lead to correctly optimized results, depending on the application features. The purpose of this work is to compare two approaches to the optimization of trigeneration plants: (i) a detailed model already presented in previous works (DCOGEN), able to perform accurate optimization and prediction of annual energy balances but requiring detailed plant definition, accurate specifications of the user demands and a significant computational time, and (ii) a simplified and faster model based on few information and a intuitive optimization strategy. The comparison is carried out for two cases, reflecting the features of industrial CHP applications based on small scale gas turbines and reciprocating engines. Results show the advantages given by the detailed model as well as the limits of simplified approaches.

Three Spool High Efficiency Small Scale Gas Turbine Concept

2017 ◽  
Author(s):  
Matti Malkamäki ◽  
Ahti Jaatinen-Värri ◽  
Antti Uusitalo ◽  
Aki Grönman ◽  
Juha Honkatukia ◽  
...  
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Small Scale ◽  
Inlet Temperature ◽  
Substantial Impact ◽  
Electrical Efficiency ◽  
Partial Load ◽  
Reciprocating Engines

Decentralized electricity and heat production is a rising trend in small-scale industry. There is a tendency towards more distributed power generation. The decentralized power generation is also pushed forward by the policymakers. Reciprocating engines and gas turbines have an essential role in the global decentralized energy markets and improvements in their electrical efficiency have a substantial impact from the environmental and economic viewpoints. This paper introduces an intercooled and recuperated three stage, three-shaft gas turbine concept in 850 kW electric output range. The gas turbine is optimized for a realistic combination of the turbomachinery efficiencies, the turbine inlet temperature, the compressor specific speeds, the recuperation rate and the pressure ratio. The new gas turbine design is a natural development of the earlier two-spool gas turbine construction and it competes with the efficiencies achieved both with similar size reciprocating engines and large industrial gas turbines used in heat and power generation all over the world and manufactured in large production series. This paper presents a small-scale gas turbine process, which has a simulated electrical efficiency of 48% as well as thermal efficiency of 51% and can compete with reciprocating engines in terms of electrical efficiency at nominal and partial load conditions.

Extending the Fuel Flexibility From Natural Gas to Low-LHV Fuel: Test Campaign on a Low-NOx Diffusion Flame Combustor

2008 ◽  
Author(s):  
Nicola Giannini ◽  
Alessandro Zucca ◽  
Christian Romano ◽  
Gianni Ceccherini
Keyword(s):  
Natural Gas ◽  
Diffusion Flame ◽  
Gas Turbines ◽  
Molar Fraction ◽  
Pollutant Emissions ◽  
Combustion System ◽  
Extensive Experience ◽  
Fuel Flexibility ◽  
Partial Load ◽  
Fuel Mixtures

Today’s Oil & Gas facility market requires enlarging machines’ fuel flexibility toward two main directions: on the one hand burning fuels with high percentages of Ethane, Butane and Propane, on the other hand burning very lean fuels with a high percentage of inerts. GE has extensive experience in burning a variety of gas fuels and blends in heavy-duty gas turbines. From a technical point of view, the tendency towards leaner fuel gases for feeding gas turbines, introduces potential risks related to combustion instability, on both combustion hardware and machines’ operability. GE Oil&Gas (Nuovo Pignone), has developed a new program aimed to extend the fuel flexibility of its Low-NOx diffusion flame combustor (Lean Head End, or LHE), which currently equips single and dual shaft 30 MW gas turbines, so that it can handle low-LHV fuels. A fuel flexibility test campaign was carried out at full and partial load conditions over an ambient and fuel range, in order to investigate both ignition limits and combustor performances, focusing on hot parts’ temperatures, pollutant emissions and combustion driven pressure oscillations. The pressurized tests were performed on a single combustion chamber, using a dedicated full-scale (full-pressure, full-temperature and full-flow) combustor test cell. Variable composition gaseous fuel mixtures, obtained by mixing natural gas with N2 from 0% up to about 50% vol., were tested. The experienced LHE combustion system up to now had been fed only with natural gas in multi can single gas combustion systems. Combustion system modifications and different burner configurations were considered to enlarge system capabilities, in order to accommodate operation on the previous mentioned range of fuel mixtures, including: nozzle orifice sizing and combustor liner modification. This paper aims to illustrate the upgraded technology and the results obtained. Reported data show combustion system’s performances, mainly in terms of pollutant emissions and operability. The performed test campaign demonstrated the system’s ability to operate at all required loads with diluted natural gases containing up to 50% vol. of N2. Results also indicate that ignition is possible with the same inerts concentration in the fuel, keeping the fuel flow at moderately low levels. As far as load operation, the combustion system proved to be almost insensitive to any tested inerts concentration, while a huge reduction of NOx emissions was observed increasing the molar fraction of N2 in the fuel gas, maintaining good flame stability.

Model of Performance of Stirling Engines

2012 ◽  
Author(s):  
J. M. Muñoz de Escalona ◽  
D. Sánchez ◽  
R. Chacartegui ◽  
T. Sánchez
Keyword(s):  
Water Consumption ◽  
Gas Turbines ◽  
Large Scale ◽  
High Efficiency ◽  
Small Scale ◽  
Detailed Model ◽  
Operation Costs ◽  
Auxiliary Power ◽  
Stirling Engines ◽  
High Investment

This work presents a detailed model of performance of Stirling engines which is expected to be of interest for the Concentrated Solar Power community. In effect, gas turbines of different types have been proposed for small and medium scale solar applications based on their reduced (even inexistent) water consumption and modularity. In the medium to large scale, conventional steam turbine based plants demand high investment costs as well as high operation costs (mostly due to water consumption). In the small-scale it is the Stirling engine which is generally consider as the prime mover of choice due to its high efficiency at moderate temperatures. In this context, this paper describes a detailed model of performance of Stirling engines. The model includes frictional and mechanical losses, heat transfer within the engine and other features like auxiliary power consumption and applies to both on-design and off-design operation. The validation of all these capabilities is also presented in the text. Hence, the model is expected to provide a valuable tool for individuals who need to assess the performance of externally heated piston engines.

scholarly journals Improved Modeling Capabilities of the Airflow Within Turbine Case Cooling Systems Using Smart Porous Media

2018 ◽  
Vol 141 (5) ◽  
Author(s):  
Yanling Li ◽  
A. Duncan Walker ◽  
John Irving
Keyword(s):  
Porous Media ◽  
Gas Turbines ◽  
Tip Clearance ◽  
Computational Time ◽  
Small Scale ◽  
Design Phase ◽  
Local Flow ◽  
Alternative Approach ◽  
Cooling Hole ◽  
Computational Fluid Dynamics Cfd

Impingement cooling is commonly employed in gas turbines to control the turbine tip clearance. During the design phase, computational fluid dynamics (CFD) is an effective way of evaluating such systems but for most turbine case cooling (TCC) systems resolving the small scale and large number of cooling holes is impractical at the preliminary design phase. This paper presents an alternative approach for predicting aerodynamic performance of TCC systems using a “smart” porous media (PM) to replace regions of cooling holes. Numerically CFD defined correlations have been developed, which account for geometry and local flow field, to define the PM loss coefficient. These are coded as a user-defined function allowing the loss to vary, within the calculation, as a function of the predicted flow and hence produce a spatial variation of mass flow matching that of the cooling holes. The methodology has been tested on various geometrical configurations representative of current TCC systems and compared to full cooling hole models. The method was shown to achieve good overall agreement while significantly reducing both the mesh count and the computational time to a practical level.

Nominal and Partial Load Operation of a Small-Scale Microturbine With a Liquid Desiccant Cooling System: An Experimental Assessment

2011 ◽  
Author(s):  
Marco Badami ◽  
Mauro Ferrero ◽  
Armando Portoraro
Keyword(s):  
Experimental Data ◽  
Energy Savings ◽  
Cooling System ◽  
Working Hours ◽  
Primary Energy ◽  
Small Scale ◽  
The European Union ◽  
Liquid Desiccant ◽  
Thermally Activated ◽  
Partial Load

In a trigeneration plant, the thermal energy recovered from the prime mover is exploited to produce a cooling effect. Although this possibility allows the working hours of the plant to be extended over the heating period, providing summer air conditioning through thermally activated technologies, it is rather difficult to find experimental data on trigeneration plant operation in the literature, and information on the performance characteristics at off-design conditions is rather limited. The paper has the aim of illustrating the experimental data of a real trigeneration system installed at the Politecnico di Torino (Turin, Italy). The system is composed of a natural gas 100 kWel microturbine coupled to a liquid desiccant system. The data are presented for both cogeneration and trigeneration configurations, and for full and partial load operations. An energetic and economic performance assessment, at rated power operation, is presented and compared with the partial load operation strategy. The primary energy savings are calculated through a widely accepted methodology, proposed by the European Union, and through another methodology, reported in literature, which, according to the Authors, seems more suitable to describe the energetic performances of trigeneration plants.

Experimental Analysis of Small Scale Cogenerators Based on Natural Gas Fired Reciprocating Internal Combustion Engine

2010 ◽  
Author(s):  
Carlo Roselli ◽  
Maurizio Sasso ◽  
Sergio Sibilio ◽  
Peter Tzscheutschler
Keyword(s):  
European Union ◽  
Combustion Engine ◽  
Primary Energy ◽  
Pollutant Emissions ◽  
Small Scale ◽  
The European Union ◽  
Interesting Application ◽  
Research Activity ◽  
Environmental Implications ◽  
Network Losses

The European Union recently established an ambitious target by 2020 that consists of increasing the utilization of renewable energy up to 20%, reducing its overall pollutant emissions to at least 20%, and achieving a primary energy saving of 20% compared to reported 1990 levels. This aim could be reached only with strong effort in different sectors, such as residential, commercial, industry, tertiary, transportation, .... In particular in the European Union a remarkable contribution to energy consumption and CO2 emissions is concentrated in residential and commercial sector. The introduction of more efficient technologies in these sectors could help in achieving the results expected by 2020. An option is given by cogeneration, defined as the combined “production” of electric and/or mechanical and thermal energy starting from single energy source, that could be considered one of the first elements to save primary energy, to avoid network losses and to reduce the greenhouse gas emissions. In particular, our interest will be focused on the microcogeneration (electric power ≤ 15 kW), which represents a valid and interesting application for residential and light commercial users. The energetic, economic and environmental implications due to the use of small scale cogeneration systems were reported, starting by an experimental research activity performed by the authors and other researchers.

scholarly journals Small-Scale Cogeneration Plant Data Processing and Analysis

2008 ◽  
Vol 45 (3) ◽  
pp. 25-33
Author(s):  
I. Veidenbergs ◽  
D. Blumberga ◽  
C. Rochas ◽  
F. Romagnoli ◽  
A. Blumberga ◽  
...  
Keyword(s):  
Data Processing ◽  
Energy Production ◽  
Primary Energy ◽  
Electricity Production ◽  
Small Scale ◽  
Cogeneration Plant ◽  
Distributed Energy ◽  
Partial Load ◽  
Plant Data ◽  
Operational Data

Small-Scale Cogeneration Plant Data Processing and Analysis In the article, the operational data on electricity and heat energy generation in a small-scale cogeneration plant are analysed. Different measurements done in the plant formed a basis for estimation and evaluation of the savings of primary energy in comparison with distributed energy production. The authors analyse the efficiency values for the heat and the electricity production in the cogeneration regime and the savings of primary energy when the cogeneration plant works with partial load.

scholarly journals The Benefits of Combining Global and Local Data—A Showcase for Valuation and Mapping of Mangrove Climate Regulation and Food Provisioning Services within a Protected Area in Pará, North Brazil

Land ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 432
Author(s):  
Robin Gutting ◽  
Ralf-Uwe Syrbe ◽  
Karsten Grunewald ◽  
Ulf Mehlig ◽  
Véronique Helfer ◽  
...  
Keyword(s):  
Global Climate ◽  
Structural Parameters ◽  
Management Strategies ◽  
Small Scale ◽  
Mangrove Forests ◽  
Food Provisioning ◽  
Local Data ◽  
Climate Regulation ◽  
North Brazil ◽  
Species Specific

Mangrove forests provide a large variety of ecosystem services (ES) to coastal societies. Using a case study focusing on the Ajuruteua peninsula in Northern Brazil and two ES, food provisioning (ES1) and global climate regulation (ES2), this paper proposes a new framework for quantifying and valuing mangrove ES and allow for their small-scale mapping. We modelled and spatialised the two ES from different perspectives, the demand (ES1) and the supply (ES2) side respectively. This was performed by combining worldwide databases related to the global human population (ES1) or mangrove distribution and canopy height (ES2) with locally derived parameters, such as crab catches (ES1) or species-specific allometric equations based on local estimates of tree structural parameters (ES2). Based on this approach, we could estimate that the area delivers the basic nutrition of about 1400 households, which equals 2.7 million USD, and that the mangrove biomass in the area contains 2.1 million Mg C, amounting to 50.9 million USD, if it were paid as certificates. In addition to those figures, we provide high-resolution maps showing which areas are more valuable for the two respective ES, information that could help inform management strategies in the future.

scholarly journals Model-Based Control of Torque and Nitrogen Oxide Emissions in a Euro VI 3.0 L Diesel Engine through Rapid Prototyping

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1107
Author(s):  
Stefano d’Ambrosio ◽  
Roberto Finesso ◽  
Gilles Hardy ◽  
Andrea Manelli ◽  
Alessandro Mancarella ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Rapid Prototyping ◽  
Nitrogen Oxide ◽  
Thermal State ◽  
Pollutant Emissions ◽  
Computational Time ◽  
Nox Emissions ◽  
Model Based ◽  
Brake Mean Effective Pressure ◽  
The Impact

In the present paper, a model-based controller of engine torque and engine-out Nitrogen oxide (NOx) emissions, which was previously developed and tested by means of offline simulations, has been validated on a FPT F1C 3.0 L diesel engine by means of rapid prototyping. With reference to the previous version, a new NOx model has been implemented to improve robustness in terms of NOx prediction. The experimental tests have confirmed the basic functionality of the controller in transient conditions, over different load ramps at fixed engine speeds, over which the average RMSE (Root Mean Square Error) values for the control of NOx emissions were of the order of 55–90 ppm, while the average RMSE values for the control of brake mean effective pressure (BMEP) were of the order of 0.25–0.39 bar. However, the test results also highlighted the need for further improvements, especially concerning the effect of the engine thermal state on the NOx emissions in transient operation. Moreover, several aspects, such as the check of the computational time, the impact of the controller on other pollutant emissions, or on the long-term engine operations, will have to be evaluated in future studies in view of the controller implementation on the engine control unit.

Documenting ancient plant management in the northwest of North AmericaThis paper was submitted for the Special Issue on Ethnobotany, inspired by the Ethnobotany Symposium organized by Alain Cuerrier, Montréal Botanical Garden, and held in Montréal at the 2006 annual meeting of the Canadian Botanical Association.

Botany ◽  
2008 ◽  
Vol 86 (2) ◽  
pp. 129-145 ◽  
Author(s):  
Dana Lepofsky ◽  
Ken Lertzman
Keyword(s):  
First Nations ◽  
Management Practices ◽  
Prescribed Burning ◽  
Management Strategies ◽  
Botanical Garden ◽  
Plant Management ◽  
Special Issue ◽  
Definitive Evidence ◽  
European Contact ◽  
Lines Of Evidence

Ethnographic literature documents the pervasiveness of plant-management strategies, such as prescribed burning and other kinds of cultivation, among Northwest Peoples after European contact. In contrast, definitive evidence of precontact plant management has been elusive. Documenting the nature and extent of precontact plant-management strategies has relevance to historians, archaeologists, managers, conservationists, forest ecologists, and First Nations. In this paper, we summarize the various lines of evidence that have been, or could be, used to document ancient cultivation in the northwest of North America. We organize this discussion by the ecological consequences of ancient plant-management practices and their documented or potential visibility in the paleo-, neo-ecological, and archaeological records. Our review demonstrates that while finding evidence of ancient plant management can be difficult, such evidence can be found when innovative research methods are applied. Further, when various independent lines of evidence are compiled, reconstructions of past plant-management strategies are strengthened considerably.

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