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The purpose of this paper is twofold: to analyze the computational complexity of the cogeneration design problem; to present an expert system to solve the proposed problem, comparing such an approach with the traditional searching methods available.

The complexity of the cogeneration problem is analyzed through the transformation of the well-known knapsack problem. Both problems are formulated as decision problems and it is proven that the cogeneration problem is np-complete. Thus, several searching approaches, such as population heuristics and dynamic programming, could be used to solve the problem. Alternatively, a knowledge-based approach is proposed by presenting an expert system and its knowledge representation scheme.

The expert system is executed considering two case-studies. First, a cogeneration plant should meet power, steam, chilled water and hot water demands. The expert system presented two different solutions based on high complexity thermodynamic cycles. In the second case-study the plant should meet just power and steam demands. The system presents three different solutions, and one of them was never considered before by our consultant expert.

The expert system approach is not a “blind” method, i.e. it generates solutions based on actual engineering knowledge instead of the searching strategies from traditional methods. It means that the system is able to explain its choices, making available the design rationale for each solution. This is the main advantage of the expert system approach over the traditional search methods. On the other hand, the expert system quite likely does not provide an actual optimal solution. All it can provide is one or more acceptable solutions.

This study is aimed to develop a novel intuitionistic fuzzy P-graph with Gaussian membership function to help decision-makers deal with complex process network systems.

Two fuzzy P-graph case studies of the cogeneration system were selected, and relevant data were collected, including the structure and flow sequence of the system, and the rate of material and product transitions between the operating units. Gaussian function membership was set according to the restriction of fuzzy upper and lower bounds. Then the α-cut was used to obtain different upper and lower bound restrictions of each membership degree. After finding the optimal and suboptimal solutions for different membership degrees, the results of non-membership and hesitation were calculated.

The proposed method will help the decision maker consider the risk and provide more feasible solutions to choose the optimal and suboptimal solutions based on their own or through experience. The proposed model in this study has more flexibility in operation and decision making.

This study is the first to propose a novel intuitive fuzzy P-graph and demonstrates the effectiveness and flexibility of the method by two case studies of the cogeneration system. However, the addition of hesitation can increase the error tolerance of the system. Even for the solutions with a high degree of membership, optimal and suboptimal solutions still exist for the decision maker to select. Since decision makers expect the higher achievement of the target requirements; thus, it is important to have more feasible solutions with a high degree of membership.

This paper describes a method developed to schedule the preventive maintenance tasks in separate and linked cogeneration plants while satisfying the maintenance and production constraints.

The proposed methodology is based on a mixed integer programming model which finds the maximum number of available power and desalting units in separate and linked cogeneration plants. To verify that the model can be implemented for a real system, a case study of scheduling the preventive maintenance tasks of a cogeneration plant in Kuwait is illustrated.

An efficient solution can be achieved for scheduling the preventive maintenance tasks and production in cogeneration plants.

The paper offers a practical model that can be used to schedule preventive maintenance for expensive equipment in cogeneration plans.

The model presented is an effective decision tool that optimises the solution of the maintenance scheduling problem for cogeneration plants under maintenance and production constraints.

The purpose of this paper is to describe a method that has been set up to schedule preventive maintenance (PM) tasks for power and water plants with all constraints such as production and maintenance.

The proposed methodology relies on the zero-one integer programming model that finds the maximum number of power and water units available in separate generating units. To verify this, the model was implemented and tested as a case study in Kuwait for the Cogeneration Station.

An effective solution can be achieved for scheduling the PM tasks and production at the power and water cogeneration plant.

The proposed model offers a practical method to schedule PM of power and water units, which are expensive equipment.

This proposed model is an effective decision-making tool that provides an ideal solution for preventive maintenance scheduling problems for power and water units in a cogeneration plant, effectively and complies with all constraints.

In the past, many business leaders viewed sustainability and profitability as mutually exclusive – if it ' s good for the environment, it ' s bad for business. Yet, over the past decade we’ve seen a growing sense of corporate responsibility and the dawning recognition that being “green” isn’t being broke. In fact, quite the opposite is true. Sustainability supports business success. This is especially true in casino design and operation. The purpose of this paper is to address sustainable design strategies for casinos that help save money. With their high energy needs and frequent remodeling campaigns, casinos offer a unique opportunity for sustainable design initiatives.

The authors detail various sustainable strategies – from using combined heat-and-power systems to streamlined access flooring and ductless air supply combinations. In addition, case studies that offer insights for best practice strategies to enhance building performance and ultimately reduce operational costs are analyzed.

It is found that with the right planning and the right technology, “good for the bottom line and good for the environment” can be achieved through sustainable design.

The paper is believed to be the first of its kind to focus on a range of sustainability initiatives to reduce energy use in casinos. The authors highlight the following design and operational strategies: daylighting, energy-efficient gaming systems and electronic gaming machines, access flooring/ductless air-supply systems, lighting and HVAC retrofits, heat recovery systems, cogeneration plants, solar arrays, fuel cells, and wind-generated power. Not only do these strategies cut operating expenditures and reduce energy demands, they create appealing and comfortable interior environments that enhance patrons’ gaming experience.

This paper aims to analyze energy and exergy analysis of solar-based intercooled and reheated gas turbine (GT) trigeneration cycle using parabolic trough solar collectors (PTC) with the use of MATLAB 2018.

In the first section of this paper, the solar-based GT is validated with the reference paper. According to the reference paper, the solar field is comprising 30 modules in series and 35 modules in parallel series, where a total of 1,050 modules of PTC are taken into consideration. In the second part of this paper, the hybridization of the solar, GT trigeneration cycle is analyzed and optimized. In the last section of this paper, the hybridization of solar, intercooled and reheated GT trigeneration systems is examined and compared.

The results examined the first section, the power produced by the cycle will be 37.34 MW at 0.5270 kg/s mass flow rate of the natural gas consumption and the efficiencies of energy and exergy will be 38.34% and 39.76%, respectively. The results examined in the second section, the power produced by the cycle will be 38.4 MW at 0.5270 kg/s mass flow rate of the natural gas consumption and accordingly the efficiency of energy and exergy is found to be 40.011% and 41.763%. Where in the last section, the power produced by the cycle will be 41.43 MW at 0.5270 kg/s mass flow rate of the natural gas consumption and the energy and exergy efficiencies will be 39.76% and 40.924%, respectively.

The author confirms that this study is original and has neither been published elsewhere nor it is currently under consideration for publication elsewhere.

The purpose of this paper is to assess renewable energy‐based cooling technologies using multi‐criteria methodology.

Analytic hierarchy process (AHP) methodology is applied to obtain the ranking of renewable energy options for cooling technology using five different criteria. In total, seven technologies were analyzed, based on the opinions obtained from experts and the extensive literature survey made and the ranking was obtained using AHP method.

The present findings revealed that the ranking for the renewable energy‐based cooling technologies were in the following order: biomass combustion, biogas, trigeneration, SPV, biomass gasifier, solar thermal storage, and hybrid technology. Only 5 per cent variation in global priority exists among top three options. This variation is considered insignificant due to rapidly varying factors such as technological advancements, government promotional schemes, fuel availability, etc. and hence these three options may be ranked equally.

The research output is helpful in identifying the technology, with promising potential for promoting technology on a wider scale. Additional attributes and sensitivity analysis can be included for further research.

The paper usefully describes the AHP methodology utilized in the present study and the ranking made for the evaluation of renewable energy‐based cooling systems. The outcome of the present study would benefit policymakers, researchers and entrepreneurs when choosing the appropriate cooling technology.

The purpose of this paper is twofold. The first is to examine in detail energy efficiency performance of German and Colombian food industries. The second is to explain the factors that have influenced energy efficiency.

Using data at the three‐digit level of aggregation, the paper compares energy efficiency across sectors of the food industry for the period 1998‐2005. Energy efficiency is analysed using the energy intensity (EI) indicator as well as a decomposition analysis. To determine the factors that have influenced energy efficiency performance, the concept of the production function is used.

The results show that both countries' food industries improved energy efficiency. During the period of study, energy consumption in the German food industry increased by an average of 1.3 per cent per year and the EI decreased 7 per cent, whereas the Colombian food industry decreased its energy consumption by an average of 1.9 per cent per the year and the EI decreased 11 per cent. However, the Colombian food industry needs 2.2 times more energy than the German food industry to produce a unit of gross production. A decomposition analysis indicated that economic and technical factors have played an important role in the energy efficiency performance because increases in economic growth and technology improvements increase the industrial sector's ability to improve energy efficiency. A second‐stage empirical analysis reveals that capital, material, investments and value‐added variables had a positive influence on energy efficiency performance in both countries. Energy prices are shown to have a positive influence on energy efficiency in the German food industry, whereas the sizes of enterprises and concentration processes played an important role on energy efficiency performance in the Colombian food industry.

The literature indicates the relative lack of attention paid to the analysis of energy use across sectors of food industry as well as the lack of studies determining the factors that have affected energy consumption and energy efficiency performance using cross‐country and cross‐sectoral comparisons.

The purpose of this paper is to outline the views of citizens on issues related to energy saving and the realization of bank products in buildings under renovation such as energy saving interventions in the building envelope, installment of maximum efficiency air-conditioning systems, etc.

The collection of data was done through a structured questionnaire. The data are important because they show the attitudes of citizens while they simultaneously assess the effectiveness of the program after the application for many years of the energy saving program by the state.

The results of the research show that with regard to responsible actions by citizens as far as impacts on climate change are concerned, cognitive factors are more important than behavioral factors. The most important reason with regard to citizens restricting the consumption of electrical energy is saving money. Finally, the vast majority of citizens declare that they know about the existence of “green” bank financial programs and claim that these contribute to environmental protection. Despite all this, a very small percentage of citizens have realized some sort of financial program in order to save energy claiming that the main reason for their choice was the country’s economic crisis.

This investigation of the views of citizens may constitute a tool both for designing of effective environmental policy but also for the assessment of energy saving programs such as the one discussed in this paper.

To analyze the structural changes in electrical energy production sector caused by rapidly growing economy and Lithuania's international environmental commitments to the EU and international organizations.

The case study estimates the environmental‐financial aspects of cogeneration system to be implemented at the boiler house. After quantitative estimation of the electric energy demands the financial comparison of long and mid‐term environmental measures is presented.

The study responds to European strategy towards doubling the amount of cogenerated electrical power and provides financial‐environmental estimates of cogeneration installations.

Installation and maintenance of co‐generation system requires high investments, however, in a long‐term perspective it would result in a substantial environmental and financial effect.

The proposed scheme could be adjusted to the local conditions of the individual country as one of energy production options to bring about a sustainable energy future.

The analyzed quantitative assessment of national cogenerated energy potential serves as a tool for implementation of sustainable energy production in practice.