Investigation Into Optimal Operation of BCHP Systems in the Air-Conditioning Season

Author(s):  
Jiacong Cao ◽  
Hong Fang

Building cooling, heating and power generation (BCHP) is important for the sustainable energy strategy in China because of its contribution to energy conservation and the reduction of CO2 emissions. The number of BCHP or small-scaled combined cooling, heating and power generation systems that have been put to use or are in the course of construction is steadily increasing in China. However, in many cases the performance of BCHP systems is not good enough, i.e., the average real exergetic efficiency of whole system is much lower than expected and the economic effect is not satisfactory. This is a problem that perplexes designers and plant owners and need be investigated so as to increase the knowledge of optimizing the operation of BCHP systems. In this paper the performance of a typical BCHP system is investigated using thermodynamic and thermoeconomic analyses based on the simulating results of off-design operation and the solution of performance optimization of the system. With the help of a great number of real running data of the system and the master data supplied by manufacturers, a model of the system operation is developed to simulate the whole domain of operation on off-design conditions. In order to shorten computer time the operation domain is described by a set of functions obtained by curve fitting using the numerical data from the simulation. Two models of optimization, of which the objective functions are the exergetic efficiency and gross benefit of the whole BCHP system separately, are established in virtue of these fitted functions. The simulation of off-design operation and the solution of the optimization problems supply a great number of useful data that form various graphs, which are to be the references to energy conservation and economic operation of the systems. The investigation indicates that there are some differences between the optimum working conditions obtained by the two optimization models, whereas it is inevitable that the system runs with some lower efficiency and less gross benefit when working at high cooling or heating load factors. By analyzing the data some significant conclusions are obtained, which will be helpful for the BCHP industry in China.

2021 ◽  
Vol 7 ◽  
pp. 3703-3725
Author(s):  
Mohammad Ehteram ◽  
Fatemeh Barzegari Banadkooki ◽  
Chow Ming Fai ◽  
Mohsen Moslemzadeh ◽  
Michelle Sapitang ◽  
...  

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Hassam Nasarullah Chaudhry ◽  
John Kaiser Calautit ◽  
Ben Richard Hughes

The effect of wind distribution on the architectural domain of the Bahrain Trade Centre was numerically analysed using computational fluid dynamics (CFD). Using the numerical data, the power generation potential of the building-integrated wind turbines was determined in response to the prevailing wind direction. The three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations along with the momentum and continuity equations were solved for obtaining the velocity and pressure field. Simulating a reference wind speed of 6 m/s, the findings from the study quantified an estimate power generation of 6.4 kW indicating a capacity factor of 2.9% for the benchmark model. At the windward side of the building, it was observed that the layers of turbulence intensified in inverse proportion to the height of the building with an average value of 0.45 J/kg. The air velocity was found to gradually increase in direct proportion to the elevation with the turbine located at higher altitude receiving maximum exposure to incoming wind. This work highlighted the potential of using advanced computational fluid dynamics in order to factor wind into the design of any architectural environment.


2014 ◽  
Vol 953-954 ◽  
pp. 925-928 ◽  
Author(s):  
Bi Bin Huang

As the positive and important supplement to large-scale power generation, distributed generation (DG) will become key measure to promote energy conservation and solve the problems of climate change in China. Due to absence of universal authoritative definition of DG, this paper summarizes the basic characteristic of DG based on the definitions in typical countries (or organizations) and carried out general definition of DG considering our national conditions and power grid features. From the views of resource, incentive policy and industry, this paper analyzed the fundamental for DG development and compared the development status in typical countries.


2021 ◽  
Vol 6 (166) ◽  
pp. 217-226
Author(s):  
O. Pavlenko ◽  
D. Velykodnyi

The article investigates the existing trends and prospects for the development of warehousing services in the system of production and processing of products, which allowed us to form the purpose of the research in this development. The chosen theme is quite topical, because warehousing processes are an integral part of the formation of supply logistics in modern production processes. One of the ways to reduce the cost of goods and services is the efficient use of resources. Ukrainian and foreign scientists have touched many questions concerning the development of the infrastructure component, solutions of optimization problems regarding the process of import-export of goods to the warehouse, but without determining the optimal values ​​of technological parameters of warehousing systems. The technological scheme of operation of the warehouse system of the enterprise LLC "MEGA CRISP» allows to see the whole chain of operations from the moment of arrival of the vehicle with cargo (containers and packaging) to the moment of sending the cargo (finished product) to the recipient; the necessary types of resources involved in these processes are also taken into account. Total costs were chosen as an evaluation indicator of the choice of an efficient supply channel. Relevant parameters of influence are taken into account: intensities of corresponding cargo flows, unit cost of the appropriate work and one hour of work of one worker, time of performance of an appropriate operation, quantity of the involved resources for performance of the appropriate operation and working time of the warehouse during the day. An imitation full-factor experiment was performed, based on the results of which a regression model in linear form with a non-zero coefficient was determined, in which each coefficient indicates the degree of influence of the relevant factor on the performance indicator. The results of determining the economic effect showed that "Variant 2" (increasing the number of workers) is the least expensive, and the level of costs is lower for all series of experiments compared to the basic variant - "Variant 1". The maximum difference is reached in 12217.8 hryvnias at the maximum loading of a warehouse. And when comparing the third and first variants: only at the maximum level of output flow (170 t / h), the third variant will be cheaper by 852.6 hryvnias. The highest level of positive value of the effect among the variants offered is "Variant 2", the level of savings will be 12,217.8 hryvnias per shift.


2021 ◽  
Vol 336 ◽  
pp. 02022
Author(s):  
Liang Meng ◽  
Wen Zhou ◽  
Yang Li ◽  
Zhibin Liu ◽  
Yajing Liu

In this paper, NSGA-Ⅱ is used to realize the dual-objective optimization and three-objective optimization of the solar-thermal photovoltaic hybrid power generation system; Compared with the optimal solution set of three-objective optimization, optimization based on technical and economic evaluation indicators belongs to the category of multi-objective optimization. It can be considered that NSGA-Ⅱ is very suitable for multi-objective optimization of solar-thermal photovoltaic hybrid power generation system and other similar multi-objective optimization problems.


Author(s):  
Thomas Wagner ◽  
Robert J. Burke

The desire to maintain power plant profitability, combined with current market fuel gas pricing is forcing power generation companies to constantly look for ways to keep their industrial gas turbine units operating at the highest possible efficiency. Gas Turbines Operation requires the compression of very large quantities of air that is mixed with fuel, ignited and directed into a turbine to produce torque for purposes ranging from power generation to mechanical drive of pumping systems to thrust for air craft propulsion. The compression of the air for this process typically uses 60% of the required base energy. Therefore management of the compression process efficiency is very important to maintain overall cycle efficiency. Since fouling of turbine compressors is almost unavoidable, even with modern air filter treatment, and over time results in lower efficiency and output, compressor cleaning is required to maintain gas turbine efficiency.


Author(s):  
Harihar Kalia ◽  
Satchidananda Dehuri ◽  
Ashish Ghosh

Knowledge Discovery in Databases (KDD) is the process of automatically searching patterns from large volumes of data by using specific data mining techniques. Classification, association, and associative classification (integration of classification and association) rule mining are popularly used rule mining techniques in KDD for harvesting knowledge in the form of rule. The classical rule mining techniques based on crisp sets have bad experience of “sharp boundary problems” while mining rule from numerical data. Fuzzy rule mining approaches eliminate these problems and generate more human understandable rules. Several quality measures are used in order to quantify the quality of these discovered rules. However, most of these objectives/criteria are conflicting to each other. Thus, fuzzy rule mining problems are modeled as multi-objective optimization problems rather than single objective. Due to the ability of finding diverse trade-off solutions for several objectives in a single run, multi-objective genetic algorithms are popularly employed in rule mining. In this chapter, the authors discuss the multi-objective genetic-fuzzy approaches used in rule mining along with their advantages and disadvantages. In addition, some of the popular applications of these approaches are discussed.


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