scholarly journals Long-term optimization case studies for combined heat and power system

2009 ◽  
Vol 13 (4) ◽  
pp. 49-60 ◽  
Author(s):  
Apostolis Polyzakis ◽  
Areti Malkogianni ◽  
Eli Gomes ◽  
Kostas Zapounidis
Keyword(s):  
Power Systems ◽  
Gas Turbines ◽  
Energy Demand ◽  
Combined Heat And Power ◽  
Small Scale ◽  
Market Conditions ◽  
Full Load ◽  
Power Stations ◽  
Electricity Infrastructure

In the next years distributed poly-generation systems are expected to play an increasingly important role in the electricity infrastructure and market. The successful spread of small-scale generation either connected to the distribution network or on the customer side of the meter depends on diverse issues, such as the possibilities of technical implementation, resource availability, environmental aspects, and regulation and market conditions. The aim of this approach is to develop an economic and parametric analysis of a distributed generation system based on gas turbines able to satisfy the energy demand of a typical hotel complex. Here, the economic performance of six cases combining different designs and regimes of operation is shown. The software Turbomatch, the gas turbine performance code of Cranfield University, was used to simulate the off-design performance of the engines in different ambient and load conditions. A clear distinction between cases running at full load and following the load could be observed in the results. Full load regime can give a shorter return on the investment then following the load. In spite combined heat and power systems being currently not economically attractive, this scenario may change in future due to environmental regulations and unavailability of low price fuel for large centralized power stations. Combined heat and power has a significant potential although it requires favorable legislative and fair energy market conditions to successfully increase its share in the power generation market.

Long-Term Operation Strategies Case Studies for Combined Heat and Power

2011 ◽  
Author(s):  
E. E. B. Gomes ◽  
C. Olmos ◽  
A. L. Polyzakis ◽  
P. Pilidis
Keyword(s):  
Gas Turbines ◽  
Energy Demand ◽  
Small Scale ◽  
Environmental Aspects ◽  
Market Conditions ◽  
Term Operation ◽  
Full Load ◽  
Power Stations ◽  
Electricity Infrastructure

In the next years Distributed Poly-generation Systems are expected to play an increasingly important role in the electricity infrastructure and market. The successful spread of small-scale generation either connected to the distribution network or on the customer side of the meter depends on diverse issues, such as the possibilities of technical implementation, resource availability, environmental aspects, and regulation and market conditions. The aim of this study is to develop an economical and parametric analysis of a Distributed Generation System based on gas turbines able to satisfy the energy demand of a typical Hotel complex. Here we show the economic performance of six cases combining different designs and regimes of operation. The software Turbomatch, the gas turbine performance code of Cranfield University, was used to simulate the off-design performance of the engines in different ambient and load conditions. A clear distinction between cases running at full load and following the load could be observed in the results. Full load regime can give a shorter return on the investment than following the load. Despite of CHP systems currently are not economically attractive, in the future this scenario may change due to the environmental regulations and unavailability of low price fuel for large centralised power stations. CHP has a significant potential but requires favourable legislative and fair energy market conditions to successfully increase its share in the power generation market.

Optimum Microturbine Sizing in Small Scale CHP Systems

2011 ◽  
Author(s):  
Mehdi Aghaei Meybodi ◽  
Masud Behnia
Keyword(s):  
Power Systems ◽  
Carbon Tax ◽  
Combined Heat And Power ◽  
Small Scale ◽  
Optimum Number ◽  
Prime Mover ◽  
Present Worth ◽  
Prime Movers ◽  
Chp System ◽  
The Impact

Microturbines are ideally suited for distributed generation applications due to their flexibility in connection methods. They can be stacked in parallel for larger loads and provide stable and reliable power generation. One of the main applications of microturbines is operating as the prime mover in a combined heat and power (CHP) system. CHP systems are considered to be one of the best ways to produce heat and power with efficient fossil fuel consumption. Further, these systems emit less pollution compared to separate productions of the same amount of electricity and heat. In order to optimally benefit from combined heat and power systems, the proper sizing of prime movers is of paramount importance. This paper presents a technical-economic method for selecting the optimum number and nominal power as well as planning the operational strategy of microturbines as the prime movers of small scale combined heat and power systems (capacities up to 500 kW) in three modes of operation: one-way connection (OWC) mode, two-way connection (TWC) mode, and heat demand following (HDF) mode. In the proposed sizing procedure both performance characteristics of the prime mover and economic parameters (i.e. capital and maintenance costs) are taken into account. As the criterion for decision making Net Present Worth (NPW) is used. In our analysis we have also considered the impact of carbon tax on the economics of generation. The proposed approach may also be used for other types of prime movers as well as other sizes of CHP system.

Development of a Simulation Model of Transient Operation of Micro-Combined Heat and Power Systems in a Microgrid

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Francesco Ippolito ◽  
Mauro Venturini
Keyword(s):  
Energy Storage ◽  
Power Systems ◽  
Thermal Energy ◽  
Energy Demand ◽  
Electric Energy ◽  
District Heating ◽  
Transient Behavior ◽  
Daily Basis ◽  
Combined Heat And Power ◽  
Electric Energy Storage

This paper presents the development of a simulation tool for modeling the transient behavior of micro-CHP (combined heat and power) systems, equipped with both thermal and electric storage units and connected with both electric and district heating grid (DHG). The prime mover (PM) considered in this paper is an internal combustion reciprocating engine (ICE), which is currently the only well-established micro-CHP technology. Different users, characterized by different demands of electric and thermal energy, both in terms of absolute value and electric-to-thermal energy ratio, are analyzed in this paper. Both summer and winter hourly trends of electric and thermal energy demand are simulated by using literature data. The results present a comprehensive energy analysis of all scenarios on a daily basis, in terms of both user demand met and energy share among system components. The transient response of the PM and the thermal energy storage (TES) is also analyzed for the two scenarios with the lowest and highest daily energy demand, together with the trend over time of the state of charge of both thermal and electric energy storage (EES).

Using Scenarios to Evaluate Technology Development Options for Power Generation Equipment

2006 ◽  
Author(s):  
Flavio J. Franco
Keyword(s):  
Power Generation ◽  
Power Systems ◽  
Gas Turbines ◽  
Nuclear Reactor ◽  
Technology Development ◽  
Thermal Power ◽  
Primary Energy ◽  
Energy Sources ◽  
Power Generation Equipment

The world of power generation is currently facing a number of challenges and uncertainties, caused by technical, economic, political, geographical and social factors. Manufacturers of power generation equipment have to design their strategies for technology development taking into account these challenges and uncertainties. They have to set goals for the medium and the long term, which involve the commitment of huge amounts of resources. At the same time, given the uncertainty of the future, they have to try to reduce their risks. Scenario-Based Planning is a methodology to deal with uncertainty in making decisions for the long term. It does not tell planners what will probably happen but helps them to understand what may happen through an understanding of the relationships of cause and effect within the environment of interest. Taking gas turbines as an example, this paper shows an application of the method to the evaluation of the markets related to different primary energy sources and different technologies, within power generation scenarios given by the IEA and scenarios proposed in previous papers by the author. Although current power generation gas turbines are predominantly designed to burn natural gas, developments based on other primary energy sources will require gas turbines to run with different fuels (synthetic gas or hydrogen, for example), helium or CO2 (in high temperature nuclear reactor systems) or hot air (in hybrid solar thermal power systems). Wind power may also require backup from gas turbines, probably incorporating significant fuel flexibility. An estimate of the value of the potential markets related to these different applications of gas turbines is made in this paper. Historical and estimated experience curves for the technologies of interest and their dependence relationships are used in this analysis, with a system dynamics model as described in [1].

Optimum Operation of Externally-Fired Microturbine in Combined Heat and Power Generation

2007 ◽  
Author(s):  
Juha Kaikko ◽  
Jari L. H. Backman ◽  
Lasse Koskelainen ◽  
Jaakko Larjola
Keyword(s):  
Power Generation ◽  
Heat Exchanger ◽  
Gas Turbines ◽  
Combined Heat And Power ◽  
Small Scale ◽  
Inlet Temperature ◽  
Control Methods ◽  
Gas Temperature ◽  
Combustion Gas ◽  
Part Load

Externally-fired microturbines (EFMT) yield promising performance in small-scale utilization of biofuels. As in larger gas turbines, the part-load performance of the EFMT is very sensitive to the selected power control method, and in general subject to severe degradation at part load. The control parameters typically include the maximum combustion gas temperature or turbine inlet temperature and the speed of the shaft. At the design point, power generation efficiency can be increased by allowing a fraction of air to bypass the burner and the combustion gas – air heat exchanger. At the same time the heat exchanger size is increased. Therefore, the by-pass flow affects the optimal sizing of the EFMT as well. In this paper, the effect of by-pass flow on the part-load performance of a single-shaft EFMT in combined heat and power generation is analyzed. In the application, the microturbine is operated by the heat demand. The control methods incorporate the use of the maximum combustion gas temperature, the speed of the shaft, and the amount of by-pass air. The focus of the study is to determine the economically optimal control scheme for the engine. The economy model uses the profit flow from the EFMT as a criterion. The results show that the inclusion of the by-pass variation in the control methods can improve the economy of temperature-controlled EFMT at part load but has no benefits when using speed control.

Performance Analysis of PEMFC Based Grid-connected Distributed Generation System

2020 ◽  
Author(s):  
Alper Nabi AKPOLAT ◽  
Erkan Dursun
Keyword(s):  
Performance Analysis ◽  
Power Systems ◽  
Distributed Generation ◽  
Energy Demand ◽  
Proton Exchange Membrane ◽  
Meteorological Data ◽  
Weather Conditions ◽  
Proton Exchange ◽  
Small Scale ◽  
Generation System

Abstract Background: Less energy consumption and more efficient use of fossil-fueled technologies are among the sustainable energy targets of modern societies. The essential activities to be achieved under these objectives are to increase the distributed generation structures and increase their applicability. The distributed generation (DG) is a small-scale version of the traditional power grid, which is supported by micro turbines, hydrogen fuel cells, wind turbines, photovoltaic (PV) modules, combine heat and power systems, and energy storage units. Methods: The aim of this research is to detail performance analyze and unit sizing of proton-exchange membrane fuel cell (PEMFC)-based grid-connected distributed generation system with the help of empirical calculations. To this end, we tried to establish the system and analyze the performance of reliable operation of the system with experimental verifications.Results and Conclusions: The results demonstrate the situation of annual production about how much rated power can be generated through the real meteorological data to dispatch the power to the constant variable loads. While, 53.56% of the total energy demand is met by the utility grid, 46.44% of the demand is met by the produced energy i.e., from microgrid. The PEMFC based hybrid microgrid at Marmara University, Faculty of Technology was analyzed in detail in this study. According to the results of the performance analysis, the important points that will be highlighted and will help the researchers working in this field are as follows. Our results are encouraging and can be validated by a larger sample size with the fine weather conditions in terms of the percentage of procurement of energy.

Assessment of Tesla Turbine Performance for Small Scale Rankine Combined Heat and Power Systems

2010 ◽  
Vol 132 (12) ◽  
Author(s):  
Van P. Carey
Keyword(s):  
Power Systems ◽  
Residential Buildings ◽  
Rankine Cycle ◽  
Combined Heat And Power ◽  
Operating Conditions ◽  
Working Fluid ◽  
Small Scale ◽  
Manufacturing Cost ◽  
Turbine Design ◽  
The Impact

For solar Rankine cycle combined heat and power systems for residential buildings and other small-scale applications (producing 1–10 kWe), a low manufacturing cost, robust, and durable expander is especially attractive. The Tesla-type turbine design has these desired features. This paper summarizes a theoretical exploration of the performance of a Tesla turbine as the expander in a small-scale Rankine cycle combined heat and power system. A one-dimensional idealized model of momentum transfer in the turbine rotor is presented, which can be used to predict the efficiency of the turbine for typical conditions in these systems. The model adopts a nondimensional formulation that identifies the dimensionless parameters that dictate performance features of the turbine. The model is shown to agree well with experimental performance data obtained in earlier tests of prototype Tesla turbine units. The model is used to explore the performance of this type of turbine for Rankine cycle applications using water as a working fluid. The model indicates that isentropic efficiencies above 0.75 can be achieved if the operating conditions are tailored in an optimal way. The scalability of the turbine design, and the impact of the theoretical model predictions on the development of solar combined heat and power systems are also discussed.

Small-Scale Well-Proven Inherently Safe Nuclear Power Conversion

2004 ◽  
Vol 126 (2) ◽  
pp. 329-333 ◽  
Author(s):  
G. A. K. Crommelin
Keyword(s):  
Heat Source ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Nuclear Power ◽  
Power Conversion ◽  
Combined Heat And Power ◽  
Small Scale ◽  
Nuclear Heat ◽  
Intermediate Heat Exchanger ◽  
The Moment

Over the last few years a number of papers have discussed the progress on studies and thoughts on small-scale nuclear power, especially nuclear power conversion systems aiming at the nonutility markets, such as the stand-alone heat generation, combined heat and power production, stand-alone electricity conversion, and ship propulsion. The design of these installations must fully comply with the philosophies as are common in these markets, where the expression “the engine is a means to an end” applies. So design to cost, design to be operated by non professional energy producers, to be managed by a pool-management system, maintained, repaired and overhauled by replacement, etc. The paper will discuss such a design. So far all papers mentioned have discussed the gas turbine directly coupled to the heat source. However, the helium turbine is considered quite a challenge for the gas turbine industry, so alternatives had to be found. At the moment the possibilities of gas turbines with an indirect heat source (to burn refuse, wood, refinery waste, etc.) are getting much more attention. The paper therefore will discuss how an inherently safe, well proven, nuclear heat source can be coupled by an intermediate heat exchanger to a recuperative, existing but adapted gas turbine.

Biomass Energy Small-Scale Combined Heat and Power Systems

2018 ◽  
pp. 629-651
Author(s):  
Daniel Büchner ◽  
Andreas Ortwein ◽  
Ernst Höftberger ◽  
Volker Lenz
Keyword(s):  
Power Systems ◽  
Combined Heat And Power ◽  
Biomass Energy ◽  
Small Scale
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