Selection of Numerical Methods and their Application to the Thermo-Ecological Life Cycle Cost of Heat Exchanger Components

Thermo-Ecological Cost with the inclusion of Life Cycle (TEC-LC) is defined as the cumulative exergy consumption of non-renewable natural resources associated with any product and its life cycle, taking into account the necessity to prevent and compensate losses caused by depletion of natural resources and the release of harmful substances into the environment. The problem of collecting data for solving TEC-LC equations is not the only one which can be faced in determining this indicator. The selection of the calculation method could also affect obtained results due to the accuracy of the selected algorithm. Numerical stability is particularly important in the case of large sets of data and in this case operations on large matrixes. The issue with a set of TEC-LC balanced equations is examined and compared on the basis of heat exchanger components

Exergo-ecological evaluation of heat exchanger

Thermodynamic optimization of thermal devices requires information about the influence of operational and structural parameters on its behaviour. The interconnections among parameters can be estimated by tools such as CFD, experimental statistic of the deviceetc. Despite precise and comprehensive results obtained by CFD, the time of computations is relatively long. This disadvantage often cannot be accepted in case of optimization as well as online control of thermal devices. As opposed to CFD the neural network or regression is characterized by short computational time, but does not take into account any physical phenomena occurring in the considered process. The CFD model of heat exchanger was built using commercial package Fluent/Ansys. The empirical model of heat exchanger has been assessed by regression and neural networks based on the set of pseudo-measurements generated by the exact CFD model. In the paper, the usage of the developed empirical model of heat exchanger for the minimisation of TEC is presented. The optimisationconcerns operational parameters of heat exchanger. The TEC expresses the cumulative exergy consumption of non-renewable resources. The minimization of the TEC is based on the objective function formulated by Szargut. However, the authors extended the classical TEC by the introduction of the exergy bonus theory proposed by Valero. The TEC objective function fulfils the rules of life cycle analysis because it contains the investment expenditures (measured by the cumulative exergy consumption of non-renewable natural resources), the operation of devices and the final effects of decommissioning the installation

Thermodynamic assessment of an integrated MILD oxyfuel combustion power plant

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Selection of Numerical Methods and Their Application to the Thermo-Ecological Life Cycle Cost of Heat Exchanger Components

Thermo-Ecological Cost with the inclusion of Life Cycle (TEC-LC) is defined as the cumulative exergy consumption of non-renewable natural resources associated with any product and its life cycle, taking into account the necessity to prevent and compensate losses caused by depletion of natural resources and the release of harmful substances into the environment. The problem of collecting data for solving TEC-LC equations is not the only one which can be faced in determining this indicator. The selection of the calculation method could also affect obtained results due to the accuracy of the selected algorithm. Numerical stability is particularly important in the case of large sets of data and in this case operations on large matrixes. The issue with a set of TEC-LC balanced equations is examined and compared on the basis of heat exchanger components

Energy, exergy and environmental quality of hard coal and natural gas in whole life cycle concerning home heating

The use of coal is suspected to have high environmental impact. Natural gas is treated as more environmentally friendly with high methane content and lower emission factors. In order to calculate the environmental impact in the whole life cycle associated with combustion of coal and natural gas all stages from “cradle to grave” should be taken into account. In particular, the transportation stage, especially in the case of life cycle analysis of gas, seems to be crucial. The distance of transmission of gas from gas fields, for instance located in Siberia, could be mainly associated with high diffuse emission of methane. The comparison of environmental impact assessment of coal and natural gas utilization for heating purposes is presented in the paper. The additional factor taken into account is localisation of boilers. In the analysis the coal is sombusted in combined heat and power plants equipped with flue gas treatment units is that released emissions are relatively remote from an urban area. In contrast, the natural gas is burned in small domestic installations with no additional FGT systems. The results of the analysis are given in 6 major impact categories. Moreover, the results of the life cycle analysis were brought into comprehensive thermo-ecological cost index, which is a cumulated exergy consumption of non-renewable resources. The results presented in the paper refer to the contemporary problem of the choice of energy sources in the context of its overall environmental efficiency

Technical and environmental viability of a European CO2 EOR system

Captured CO2 from large industrial emitters may be used for enhanced oil recovery (EOR), but as of yet there are no European large-scale EOR systems. Recent implementation decisions for a Norwegian carbon capture and storage demonstration will result in the establishment of a central CO2 hub on the west-coast of Norway and storage on the Norwegian Continental Shelf. This development may continue towards a large-scale operation involving European CO2 and CO2 EOR operation. To this end, a conceptual EOR system was developed here based on an oxyfuel power plant located in Poland that acted as a source for CO2, coupled to a promising oil field located on the Norwegian Continental Shelf. Lifecycle assessment was subsequently used to estimate environmental emissions indicators. When averaged over the operational lifetime, results show greenhouse gas (GHG) emissions of 0.4 kg CO2-eq per kg oil (and n kWh associated electricity) produced, of which 64 % derived from the oxyfuel power plant. This represents a 71 % emission reduction when compared to the same amount of oil and electricity production using conventional technology. Other environmental impact indicators were increased, showing that this type of CO2 EOR system may help reach GHG reduction targets, but care should be taken to avoid problem shifting