Optimization of a Small Size CHP System by Means of a Fully Transient Numerical Approach

2017 ◽  
Author(s):  
Luigi Chiantera ◽  
Massimo Milani ◽  
Luca Montorsi ◽  
Matteo Stefani
Keyword(s):  
Energy Efficiency ◽  
Ad Hoc ◽  
Electric Energy ◽  
Numerical Approach ◽  
Combined Heat And Power ◽  
Battery Capacity ◽  
Energy Conversion Systems ◽  
One Year ◽  
Chp System

The paper investigates the performance of a combined heat and power system by means of a fully dynamic numerical approach. An ad-hoc library for the simulation of energy conversion systems is developed under the OpenModelica open source platform; the library includes the main components that usually equip a Combined Heat and Power (CHP) system and they can be connected as they are logically connected in the real plant. Each component is modelled by means of equations and correlations that calculate their performance on a time dependent basis. Therefore, many configurations can be evaluated not only in terms of cumulative annual results or average performance, but the instantaneous behavior can be investigated. The numerical library is constructed using the lumped and distributed parameter approach and it is validated by comparing the numerical results with the measured values over a one-year time period. The prediction capabilities of the proposed numerical approach are evaluated by simulating a case study of a health spa. This case study is selected since it is characterized by significant requirements of both thermal and electric energy. The comparison demonstrated that the calculated results are in good agreement with the measurements in terms of both annual values and distribution over the reference period. Furthermore, an optimization algorithm is adopted and linked to the developed library in order to estimate the best size of different components of the CHP system according to a number of constraints. This feature is particularly important when addressing the energy efficiency of a complete system that is depending on a number of interdependent variables. Therefore, the case study is investigated by accounting also for additional technologies that can be further enhance the performance of the system both in terms of energy consumption and economic investment. In particular, the numerical model is used to optimized the CHP energy efficiency by estimating the best trade-off between the reduction of the energy purchased and the overall cost of the system. The application of PV panels and electric energy accumulators is also investigated and the simulation demonstrates that the size of the cogeneration unit equal to 48 kW, the number of PV panels of 299 and the battery capacity of 45 kWh provide the lowest amount of energy purchased, while the best return of investment is obtained by the CHP unit of 40 kW along with 109 PV panels and a battery of 40 kWh.

Thermodynamic Analysis of Minimum Extraction Ratio for Coal-Fired CHP Plants

2014 ◽  
Vol 472 ◽  
pp. 1052-1056
Author(s):  
Chun Hui Liao ◽  
Zhi Gang Zhou ◽  
Jia Ning Zhao
Keyword(s):  
Energy Efficiency ◽  
Thermodynamic Analysis ◽  
District Heating ◽  
Combined Heat And Power ◽  
Exergy Efficiency ◽  
Extraction Ratio ◽  
Dual Purpose ◽  
Heat Demand ◽  
Chp System ◽  
Minimum Heat

For evaluating the performance of combined heat and power district heating (CHP-DH) system, some thermodynamic indicators of CHP system, include energy efficiency, exergy efficiency, RPES and RAI, are introduced in this paper. Based on two condensed and heating dual purpose plants, the values of these indicators are calculated with different extraction ratio. The results show that RAI and RPES are more reasonable to be used to assess CHP-DH system and there is a minimum extraction ratio for each unit, which is 0.4 for given plants in this paper, to keep CHP-DH beneficial compared with separate heat and power (SHP) system. Besides, the minimum heat demand of CHP-DH system should be larger than the supplied heat correspond to minimum extraction ratio.

scholarly journals The application of the TES technology in CHP heating system with Chinese demand profiles——A techno-economic feasibility case study

2019 ◽  
Vol 111 ◽  
pp. 06010
Author(s):  
Ruoyu Zhang ◽  
Haichao Wang ◽  
Xiaozhou Wu ◽  
Xiangli Li ◽  
Lin Duanmu
Keyword(s):  
Mathematical Model ◽  
Heating System ◽  
Combined Heat And Power ◽  
Economic Benefits ◽  
Economic Feasibility ◽  
Electricity Pricing ◽  
Peak Shaving ◽  
Optimum Type ◽  
Chp System

The thermal energy storage (TES) technology is an effective method to enhance the planning and the economy of the combined heat and power (CHP) plants, while it has still not been broadly promoted in China. In this paper we firstly establish a mathematical model for a Chinese CHP plant with TES. Then the EnergyPRO software is used to find the optimum type of the TES tank in a three-tariff electricity pricing market and the operation strategy of the CHP plant with the selected TES tank is studied. Thirdly, the economic benefits of the system with/without TES is evaluated. The results show that adding a TES tank with volume of 24000m3 can significantly increase operational profits of the CHP system and reduce the use of peak-shaving heat source.

scholarly journals An integrated approach to energy use: the case study of the ACEA site

2019 ◽  
Vol 119 ◽  
pp. 00023
Author(s):  
Viviana Negro ◽  
Davide Mainero
Keyword(s):  
Energy Recovery ◽  
Energy Use ◽  
Electric Energy ◽  
Integrated Approach ◽  
Combined Heat And Power ◽  
Organic Fraction ◽  
Horizon 2020 ◽  
Gas Network ◽  
Purification System

Currently, ACEA utilises biogas obtained from the treatment of the organic fraction of municipal solid waste for thermal and electric energy recovery through endothermic engines (3 MW, in total). By 2020, the biogas produced at the site will no longer be used as a fuel for the combined heat and power units, but it is expected to feed a purification system in order to obtain a flow of biomethane to be injected into the natural gas network. This is part of the Italian strategy to achieve the Horizon 2020 European targets aimed at promoting the renewable production of transport fuels. In order to encourage sustainability and innovative prototype technologies, ACEA has also been involved in some European research projects, in particular for the conversion of biogas into other energy carriers. furthermore, ACEA ha recently built a flexible experimental platform that can used for the validation step of prototypes in an industrial field.

The Impact of Australia’s Carbon Price on the Optimisation and Selection of Gas Turbine CHP System

2013 ◽  
Author(s):  
Chanel A. Gibson ◽  
Mehdi Aghaei Meybodi ◽  
Masud Behnia
Keyword(s):  
Gas Turbine ◽  
Carbon Price ◽  
Combined Heat And Power ◽  
Present Worth ◽  
Dual Connection ◽  
Chp System ◽  
The Impact ◽  
Optimum Working ◽  
Selection Of

This paper aims to indentify the impact of Australia’s carbon pricing mechanism on the optimization of a gas turbine combined heat and power (CHP) system using a thermo-economic approach. Three economic scenarios were considered: no carbon price (case one); carbon price and not liable (case two); and a carbon price and liable (case three). With the intention of demonstrating the methodology used and to identify the impact of the carbon price quantitatively, a case study was utilized. Pricing data sourced from an ongoing investigation at this institution was employed to facilitate the three economic scenarios in addition to the yearly price fluctuations. The system was permitted to operate at off-design conditions in order to determine the optimum working conditions for each month. The analysis drew on the economic indicators of net present worth and payback period. Two connection modes to the grid were considered: a single connection that allowed only for the purchasing of supplementary electricity from the grid and a dual connection which allowed both purchasing and selling of electricity.

Climatization, Energy Efficiency and Environmental Protection

2017 ◽  
Vol 3 (2) ◽  
pp. 53
Author(s):  
Galvin A. Toala Arcentales ◽  
Reinaldo Guillén Gordín ◽  
Antonio Vázquez Pérez ◽  
Alfredo Zambrano Rodríguez
Keyword(s):  
Energy Efficiency ◽  
Environmental Protection ◽  
Technological Innovation ◽  
Electric Energy ◽  
Ozone Layer ◽  
The Other ◽  
Relevant Result ◽  
Other Hand ◽  
Conditioning Equipment

It is known that approximately 15% of the energy consumed in Ecuador is used for the operation of climate conditioning equipment and, on the other hand, most of the existing technology operates on the basis of the use of refrigerant gases Are invasive to the ozone layer. In the work, a case study is shown that allows the identification of a relevant result linked to an action of technological innovation based on the conversion of the R-22 gas by the R-290 gas, thus reducing the consumption of electric energy and reducing the Environmental inventory of the institution, achieving a better performance of the technology.

scholarly journals Techno, Economic and Environmental Assessment of a Combined Heat and Power (CHP) System—A Case Study for a University Campus

Energies ◽  
2018 ◽  
Vol 11 (5) ◽  
pp. 1133 ◽  
Author(s):  
Khuram Amber ◽  
Tony Day ◽  
Naeem Ratyal ◽  
Adnan Kiani ◽  
Rizwan Ahmad
Keyword(s):  
Environmental Assessment ◽  
Combined Heat And Power ◽  
University Campus ◽  
System A ◽  
Chp System

scholarly journals Case Study of a Complex Informing System: Joint Interagency Field Experimentation (JIFX)

10.28945/2289 ◽  
2015 ◽  
Vol 18 ◽  
pp. 063-109
Author(s):  
William F Murphy ◽  
Sandra Sanchez Murphy ◽  
Raymond R Buettner ◽  
Grandon Gill
Keyword(s):  
Ad Hoc ◽  
Theoretical Frameworks ◽  
Case Research ◽  
Incremental Value ◽  
New Ideas ◽  
Field Experimentation ◽  
One Year ◽  
Ad Hoc Collaborations

The Joint Interagency Field Experimentation (JIFX) event, organized by the Naval Postgraduate School (NPS), is conducted 3-4 times a year at various locations. The four day event can be characterized as an informing system specifically designed to facilitate structured and unstructured communications between a variety of parties—e.g., software developers, inventors, military and civilian users of various technologies, academics, and agencies responsible for identifying and procuring technology solutions—that frequently are constrained in their informing activities in more restrictive venues. Over the course of the event, participants may observe technology demonstrations, obtain feedback from potential users, acquire new ideas about their technologies might be employed and, perhaps most significantly, engage in ad hoc collaborations with other participants. The present paper describes an exploratory case research study that was conducted over a one year period and involved both direct observation of the event and follow-up interviews with 49 past participants in the event. The goal of the research was to assess the nature of participant-impact resulting from attending JIFX and to consider the consistency of the findings with the predictions of various theoretical frameworks used in informing science. The results suggest that participants perceived that the event provided significant value from three principal sources: discovery, interaction with potential clients (users) of the technologies involved, and networking with other participants. These findings were largely consistent with what could be expected from informing under conditions of high complexity; because value generally derives from combinations of attributes rather than from the sum of individual attributes, we would expect that overall value from informing activities will be perceived even though estimates of the incremental value of that informing cannot be made.

A Numerical Approach for the Evaluation of the Energy Efficiency in Ventilated Façade

2018 ◽  
Author(s):  
Massimo Milani ◽  
Luca Montorsi ◽  
Matteo Venturelli
Keyword(s):  
Heat Transfer ◽  
Energy Efficiency ◽  
Thermal Insulation ◽  
Radiative Heat ◽  
Fluid Dynamic ◽  
Electric Energy ◽  
Numerical Approach ◽  
Air Gap ◽  
Radiative Heat Exchange ◽  
Ventilated Facade

The paper studies the ventilated façade as a potential alternative to conventional coating technologies for the thermal insulation of building’s external walls. The ventilated façade is modeled by means of a CFD approach that accounts for the full 3D-geometry of the building, the walls thickness and materials’ thermal properties. The effects of the windows on the heat losses and in the performance of the ventilated façade are modeled in order to accurately characterize the thermal behavior of the system. The solar radiative heat transfer during two representative days of the year is considered in the analysis and a multiband thermal radiation is adopted to capture the different nature of radiative heat exchange according to the light wavelengths. The numerical approach enables to estimate the thermo-fluid dynamic behavior of the system and the temperature distribution and the velocity flow field within the air gap between the walls are addressed and their influence on the heat transfer through the building’s external walls is determined. The CFD analysis is employed to compare different configurations of the ventilated façade for improving the thermal insulation of the building; the performance of each scenario is determined in terms of electric energy and fuel consumption for the air conditioning and the heating system. Thus, the potential saving of the energy cost for ambient thermal conditioning is evaluated. The analysis investigates the effects on the energy efficiency of different geometrical features of the system such as the height of the building and the air gap thickness and theoretical correlations are derived in order to estimate the best tradeoff between the energy efficiency of the building and the investment of the ventilated façade configuration.

scholarly journals A Critical Review of the Modeling and Optimization of Combined Heat and Power Dispatch

Processes ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 441 ◽  
Author(s):  
Kody Kazda ◽  
Xiang Li
Keyword(s):  
Combined Heat And Power ◽  
Search Algorithms ◽  
Metaheuristic Algorithms ◽  
Research Attention ◽  
Modeling And Optimization ◽  
Electricity System ◽  
The Subject ◽  
Chp System ◽  
Emission Dispatch

Combined heat and power (CHP) systems are attracting increasing attention for their ability to improve the economics and sustainability of the electricity system. Determining how to best operate these systems is difficult because they can consist of many generating units whose operation is governed by complex nonlinear physics. Mathematical programming is a useful tool to support the operation of CHP systems, and has been the subject of substantial research attention since the early 1990s. This paper critically reviews the modeling and optimization work that has been done on the CHP economic dispatch problem, and the CHP economic and emission dispatch problem. A summary of the common models used for these problems is provided, along with comments on future modeling work that would beneficial to the field. The majority of optimization approaches studied for CHP system operation are metaheuristic algorithms. A discussion of the limitations and benefits of metaheuristic algorithms is given. Finally, a case study optimizing five classic CHP system test instances demonstrates the advantages of the using deterministic global search algorithms over metaheuristic search algorithms.

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