Thermo-ecological Cost Research Articles

Assessing the exergy degradation of the natural capital: From Szargut's updated reference environment to the new thermoecological-cost methodology

This paper shows the common developments performed by the Institute of Thermal Technology and the Research Centre for Energy Resources and Consumption regarding the assessment of natural resource degradation. Particularly, it shows the last model of the Szargut's Reference Environment, which was updated with new geological and geochemical information not available when it was originally developed. This R.E. allows for a more precise assessment of the chemical exergy of natural resources. The paper further shows the concept of the Exergy Replacement Costs (ERC) and the model of Thanatia, a theory that serves to assess the concentration exergy of mineral resources based on their scarcity degree in Nature. The combination of the ERC concept with the Thermo-Ecological Cost method (TEC), originally proposed by Szargut to assess products considering the exergy associated to the consumption of non-renewable resources extracted directly from Nature, gave birth to the TERC methodology, to better assess the degradation of the mineral capital.

Exergetic and thermo-ecological assessment of heat pump supported by electricity from renewable sources

Abstract Heat pumps (HP) represent an attractive option as a heat source, since they utilise “free” ambient heat. However, as they need to be driven by electric energy, their ecological efficiency depends not only on their performance, but also on the energy mix used for electricity generation. Effectiveness of HP can be improved by applying renewable energy sources (RES) providing electricity to drive the system. In order to properly assess such a system, it should be evaluated within a global balance boundary reaching the level of primary resources. The authors propose the use of thermo-ecological cost (TEC) indices for exergo-ecological assessment. TEC is defined as cumulative consumption of non-renewable exergy connected with the fabrication of a particular product. TEC also includes additional consumption of non-renewable natural resources which results from the necessity of compensating environmental losses caused by rejection of harmful substances to the environment. Within the paper, a HP system has been analysed from the ecological point of view. The system consists of a heat pump driven by electricity, and photovoltaic panels or wind turbines as a basic source of electricity. The balance of electricity demand for HP is complemented by electricity from grid. To evaluate this system, real environmental data on solar radiation, wind and ambient temperature deciding on heat demand have been taken into account. The authors present the ecological benefits resulting from supporting heat pumps by electricity generated in RES. It has been demonstrated by comparing results obtained within local and global balance boundaries, that the second approach should be consequently applied when systems based on a mix of renewable and non-renewable energy are analysed, since the first approach may lead to misleading conclusions.

Environmental assessment of wind turbine systems based on thermo-ecological cost

An increased wind capacity penetration reduces loading on conventional thermal units causing higher fuel requirements due to the off-design operation. Regarding the environmental analysis, such an adverse effect should be allocated to the operational phase of wind turbines. In the present work, we apply Thermo-ecological Cost (TEC) to evaluate the environmental performance of wind power systems operating in Poland and Italy. The analysis focuses on the quantitative assessment of the effect of additional chemical energy consumption due to part-load operation of the conventional power units in both analyzed electricity systems. We present the results for two different dispatch strategies. The results confirm high environmental effectiveness of wind power systems. However, the TEC resulting from the compensation for wind generation variations has a significant contribution to the overall LC-TEC index. In particular, without considering the effect of compensation, the TEC for wind turbines are from 47 to 65 times lower than for coal-fired power plants and 35 to 48 times lower than for NGCC plants. Concerning the real load conditions, and considering the effects resulting from the compensation for wind generation variations, the TEC index for this phase contributes between 36% and 75% to the total TEC value.

Analysis of life cycle thermo-ecological cost of electricity from wind and its application for future incentive mechanism

In this paper, we apply a life cycle thermoecological cost (LC-TEC) approach to evaluate the environmental performance of wind turbines with different capacities and performance characteristics. LC-TEC expresses the cumulative consumption of non-renewable exergy burdening the fabrication of the considered consumption of the product with the additional inclusion of necessity of compensating adverse environmental effects due to harmful waste products rejection. Differently, from what has been recently done in the literature on the environmental performance of wind turbines, where the attention has been mainly drawn by analysis of single turbine, we focus on the synthesis of the results for wind turbines with different capacities and the generalisation of the results under different environmental conditions.The selected functional unit for the comparison was 1 MJ of produced electricity, assuming a service lifetime equal to 20 years. Concerning the contribution analysis, the construction phase is the most intensive one for wind energy technologies with a share varying from 64 to 77% in the overall effect. Substantial differences in LC-TEC are observed for wind turbines of different capacity and different locations of the power plant. Results show that the LC-TEC of electricity significantly decrease while the turbine nominal power increases. For instance, for the average site, described by Weibull distribution parameters of mean wind speed of 5 m/s and shape coefficient 2, the TEC-LC for 1 kW micro wind turbine is estimated to be equal to 0.436 MJex/MJ, while for a larger, 2 MW one, fall in the range of 0.053–0.063 MJex/MJ. We found that a power function can successfully describe such a trend. Moreover, we observed considerable changes in the final results for different Weibull distribution parameters. Specifically, the LC-TEC differs significantly for the sites with lower mean wind speed and different shape factors.Finally, we propose the supporting system for wind energy basing on the LC-TEC and pro-ecological taxing. According to this concept, the power units with LC-TEC below unity are to be supported, and the proposed level of pro-ecological support (ExTAX – Exergy TAX) is proportional to the thermo-ecological cost.The obtained results of exergy supporting for wind energy technologies are applied in the Italian electricity market and compared with the existing financing system for wind energy based on green certificates and feed-in tariff system.

Exergo-Ecological Assessment of Waste to Energy Plants Supported by Solar Energy

Hybridization of Waste to Energy (WtE) plants with solar facilities can take competing energy technologies and make them complementary. However, realizing the benefits of the solar integration requires careful consideration of its efficiency. To analyse such systems from the point of view of resource efficiency, the pure energy analysis is not sufficient since the quality of particular energy carriers is not evaluated. This work applies the exergo-ecological analysis using the concepts of thermoecological cost (TEC) and exergy cost for the performance evaluation of an integrated Solar-Waste to Energy plant scheme, where solar energy is used for steam superheating. Different plant layouts, considering several design steam parameters as well as different solar system configurations, in terms of area of heliostats and size of the thermal storage tank, were studied. The results for the solar integrated plant scheme were compared with the scenarios where superheating is performed fully by a non-renewable energy source. The presented results of exergy cost analysis indicate that the most favorable system is the one supported by non-renewable energy. Such an analysis does not consider the advantage of the use of renewable energy sources. By extending the system boundary to the level of natural resource and applying the thermoecological cost analysis, an opposite result was obtained.

Thermo-ecological evaluation of an integrated MILD oxy-fuel combustion power plant with CO2 capture, utilisation, and storage – A case study in Poland

This study investigated the environmental benefits of a new boiler design for a fossil fuel-based power plant with CO2 capture, utilisation, and storage (CCUS) through thermo-ecological cost (TEC) analysis. MILD oxy-fuel combustion (MOFC) combines the advantages of the moderate and intense low-oxygen dilution (MILD) combustion and oxy-fuel combustion (OFC) to achieve efficient and environmentally justified CO2 capture from fossil fuel-based power generation. The advantages of MOFC application are: (i) it increases the efficiency of the coal-fired boiler, (ii) it increases the purity of the CO2 in the flue gases, (iii) it reduces the oxygen consumption of the boiler by using lower oxidiser excess, and (iv) it reduces the energy consumption associated with CO2 recirculation. Therefore, using MOFC decreases the penalty of the overall net energy efficiency associated with the CO2 capture from coal-fired power plants.The environmental analysis in this study considered the TEC, which measures the depletion of non-renewable natural resources by estimating the cumulative exergy consumed by the production processes. Moreover, the additional exergy consumption that compensates for the negative impact of harmful emissions has also been considered. The data for the new boiler design were obtained by CFD modelling, while the other technological modules of the integrated MOFC power plant were modelled by process modelling software. The data concerning the CO2 transport, utilisation, and storage were obtained from the available databases and literature.Three configurations of the power plant were modelled and analysed from the environmental point of view. The first two were the reference coal-fired power plants (the conventional power plant and the oxy-fuel combustion power plant with CO2 capture), while the third case used the same power plant configuration but with an MOFC boiler. The results were compared to other CO2 capture options, such as post-combustion, using the electro-energy system in Poland as the reference. The results emphasised the importance of the emissions and energy consumption occurring upstream (e.g. coal extraction and transport) and downstream (e.g. CO2 transport and storage) of the project when assessing the environmental impact factors. Additionally, two industrial options for CO2 utilisation were proposed, because CO2 storage is generally opposed by the public.

Thermo-ecological cost of electricity from renewable energy sources

Nowadays, the society faces the challenge of continuous supply of electricity. Energy from two different sources of origin such as renewable and non-renewable is used to meet the needs of modern humankind. The paper presents the findings concerning the thermo-ecological cost assessment of renewable energy sources defining their total impact on the environment. Biogas, wind and photovoltaic power plants were evaluated to present the results of cumulative environmental impact based on the thermo-ecological cost methodology. Polish law regulations and the prediction of the future energy mix structure are described to emphasize the importance of selected technologies. The measurements data of real renewable energy units in Poland and the characteristics of components were used to calculate thermo-ecological cost of electricity originating from renewable sources. Moreover, different phases of the production chain are considered to present results in total life cycle of the respective technologies. In the calculations, continuous availability of conventional power plants for stabilizing the current electricity needs is taken into account. Finally, the results of this study prove that biogas power plants cause lower environmental impact than wind and photovoltaic technologies.

Environmental impacts of electricity production of micro wind turbines with vertical axis

Abstract The increasing focus on the installation of sustainable energy systems has resulted in a wide range of micro wind turbine systems being introduced in the market. Although the majority of the commercially installed wind turbines are the horizontal axis ones, vertical axis turbines are considered as a promising technology for the future. It is generally known that the environmental impacts generated in the operational stage of wind turbines are significantly lower than the ones, generated by the fossil fuels based systems. The use of the Life Cycle Assessment (LCA) enables to assess the environmental impacts of a product or a process, taking into consideration also raw material extraction, manufacturing, distribution, and disposal stages of life cycle. The contribution of these stages is often critical for the environmental impacts of the bioenergy systems. This study contributes to the existing knowledge by presenting the detailed LCA of electricity produced in micro wind turbines with the vertical axis. For the impact assessment, two methods were selected: the CML-IA and Thermo-Ecological Cost in the whole life cycle (TEC-LC). Firstly, the environmental impacts of electricity generated by wind turbines with 1 and 3 kW nominal power were evaluated and compared with each other and with the impacts of the grid electricity produced in the Italian energy mix. Next, the sensitivity of the impact results on the wind characteristics variability was investigated. Results showed that the 3 kW turbine has, in general, lower values of the environmental impact indicators per unit of produced energy than the 1 kW turbine from 27% lower Global Warming Potential (GWP) to 75% lower Abiotic Depletion (ADP). The impacts per unit of produced energy in the analysed micro wind turbines are lower than the corresponding impacts for the grid electricity generated in the Italian energy mix for nine impact indicators out of twelve. It was also observed that wind distribution parameters strongly influence the environmental impacts of the electricity produced by the considered turbines, leading to values higher than those obtained for Italian energy mix for low wind average speed and, even more, for low variances of the average wind speed.

Pro-Ecological Exergy Tax of Electricity

The concept of the pro-ecological tax or support is proposed in this article. It could replace the existing subsidy mechanisms for renewable power technology or could represent the ecological taxes burdening the fabrication of consumer products based on nonrenewable resources, e.g., electricity from the conventional fossil fuel power plants. Moreover, the proposed concept for renewable power technologies could represent a new system of subsidy based on physical laws. The proposed pro-ecological tax or support is defined as proportional to the thermo-ecological cost (TEC). TEC expresses the cumulative consumption of nonrenewable exergy burdening the fabrication of the considered consumption of the product with the additional inclusion of necessity of compensating adverse environmental effects due to harmful waste products rejection. It is assumed that calculating new exergy tax or subsidy for electricity, the total cost burdening the final consumer remains the same. This principle determines the coefficient of proportionality between the cumulative consumption of nonrenewable exergy (TEC) and the value of the tax or subsidy. In the case of nonrenewable electricity generation, the TAX causes the largest price growth. The higher is the efficiency of power technology, and the lower is the TEC of fuel, the lower tax is provided. In this paper, the prices of electricity produced from renewable and nonrenewable resources are calculated, taking into account the unavoidable consumption of resources. The unavoidable exergy consumption is caused due to the power plant construction, which is distributed through the whole life cycle of the plant. Results of calculation of proposed subsidies are compared with the current Polish system for supporting renewable power technologies.

Exergo-ecological and economic evaluation of a nuclear power plant within the whole life cycle

The multi-criteria analysis of different power technologies takes into account TEC (thermo-ecological cost); direct and cumulative emissions; and economic evaluation. The environmental and ecological comparison of the planned nuclear power plant with the existing conventional ones (coal and gas plants) requires the evaluation of the whole life cycle of electricity generation. The main cause of the imperfection of nuclear fuel cycle appears in the stage of conversion, enrichment and nuclear fuel fabrication. TEC analysis takes into account all connected process starting from natural resources extracting, through all related processes influencing product generation, up to disposal or recycling. For this reason, TEC and exergy efficiency evaluate the nuclear fuel life cycle. TEC expresses the total (cumulative) exergy consumption of non-renewable resources burdening the analysed product, which means exergy assembly of the whole cycle of this product. TEC also takes into account the additional non-renewable exergy consumption required for environmental losses mitigation caused by the harmful emissions. A significant amount of GHG (greenhouse gasses) emissions is not covered by the direct analysis since the CO2 emissions also occur in the stages of mining and transportation of fuel production. The nuclear power units are characterized by lower GHG emissions than the coal and gas technologies, for which the GHG emissions is on a comparable level. Additionally, the economic analysis revealed that the investment cost of the nuclear power plant is significantly higher than those of coal or gas power plant the unit cost of electricity generated by the nuclear installation could be about twice lower than from other technologies. It results from an operating cost: the cost of fuel and the fee of direct GHG emissions are higher for coal and gas technology than for nuclear power plant. The nuclear power plants seem to be the competitive technologies for the coal or gas installation and should be taken into account while planning the policy for energy generation.

Application of multi-criteria methods to compare different solutions of supplying buildings in electricity from photovoltaic systems

Nowadays, the technologies of electricity generation in distributed systems are usually associated with Renewable Energy Sources (RES). The choice of the construction site depends mainly on the availability of the power system. However, energy planning, especially in case of RES, is a complex process involving multiple and often conflicting objectives. The complexity of the selection of the electricity system is typically addressed with the use of multi-criteria tools, involving all of the considered criteria and also different methods of their aggregation. The result is a final ranking of the available alternatives. This paper describes the application of a multi-criteria decision tool for the comparative analysis of the use of alternative options of the PV technology for electricity production. Four decision variants are considered, including the different construction of solar farms (static and movable structure) and different types of configuration of individual installation (off and on-grid). The construction of each new sources of electricity generation, including PV, is the multi-threaded and multi-dimensional decision problem. The criteria used in the analysis combine economic, environmental and social issues. The first of the considered criterion is the Net Present Value (NPV) which determines the economic viability of the project. The second criterion, thermo-ecological cost (TEC), connecting energy and environmental issues. Finally, the Land Use (LU) is considered as a social criterion. As aggregation function, the Weighted Sum Method (WSM) is used. The sensitivity analysis of the criteria weights was performed with the use of a novel method involving Monte Carlo simulation and a method of data reconciliation.

Environmental analysis of bio-CCS in an integrated oxy-fuel combustion power plant with CO2 transport and storage

Oxy-fuel combustion (OFC) belongs to one of the three commonly known clean coal technologies for which practical application may be in the offing. Similarly to conventional power plants, there is a possibility of biomass co-firing, thus an additional reduction of CO2 emission is possible. Including the biomass in the fuel mixture of an integrated OFC power plant allows to obtain the so called “neutral” CO2 status as biomass combustion does not contribute to anthropogenic CO2 emissions. In OFC power plants without biomass co-firing, even if 100% of CO2 is captured, there are still additional CO2 emissions in processes like fossil fuel extraction, transportation and preparation. The same assumption applies also to biomass and other materials (e.g. limestone or raw water). A higher share of biomass in the fuel mixture can lead to “negative” CO2 emissions with may be helpful to compensate the unfulfilled goals in other sectors where reduction is required. The paper presents the system approach to the environmental analysis based on the “input–output” method and both the index of the thermoecological cost and cumulative CO2 emissions. Thermoecological cost includes, the cumulative exergy consumption of non-renewable energy sources and additional exergy consumption due to harmful emissions to the atmosphere. In order to investigate the impact of bio-CCS (both biomass co-firing and dedicated biomass boilers) on the net thermoecological cost of electricity production and cumulative CO2 emissions five cases have been analyzed.

Exergy Life Cycle Assessment of soil erosion remediation technologies: an Italian case study

In this work, the primary resources assessment of four different soil erosion remediation technologies, Geo-nets, Bio-mats, Geo-cells and Deep Rooting Plants (DRP), is performed applying the approach of the Exergy Life Cycle Assessment (ELCA). The ELCA provides a comprehensive framework to assess the primary resources requirements of products by means of the conversion of primary flows of energy and raw materials absorbed by a production process into exergy.The soil erosion technologies described in the work are analysed according to two complementary indicators: the annual average soil loss and the life cycle primary exergy requirements. The primary exergy requirement of the different applications is measured by means of three ELCA indicators: the Cumulative Exergy Demand (CExD), the Thermo-Ecological Cost (TEC) and the Cumulative Exergy Extraction from Natural Environment (CEENE). The specific context of the application is a highway slope of the size of 1 hectare situated along the A1 highway, near the town of Fabro (TR), in Italy.The results indicate that DRPs are the most suitable solutions. However, TEC, CExD and CEENE indexes of these technologies suggest the existence of hidden impacts related to land use. The same result characterises also Bio-mats, the technology with the highest contribution of renewable material along the life cycle phases. In conclusion, this work shows that the use of exergy based impact indexes for the environmental impact assessment supplies a wider framework and deeper insights of the environmental performance of production processes and products.

Application of the Stirling engine driven with cryogenic exergy of LNG (liquefied natural gas) for the production of electricity

LNG (liquefied natural gas) delivered by means of sea-ships is pressurized and then regasified before its introduction to the system of pipelines. The utilization of cryogenic exergy of LNG for electricity production without combustion of any its portion is analyzed. For the conversion of LNG cryogenic exergy into electricity, the Stirling engine is proposed to be applied. The theoretical thermodynamic model of Stirling engine has been applied. This model is used to investigate the influence of pinch temperature in heat exchangers, engine compression ratio and dead volumes ratios on the thermodynamic parameters of the Stirling engine. The results of simulation represent the input data for investigations of thermodynamic performance of the proposed system.In order to evaluate the thermodynamic performance of the proposed process, an exergy analysis has been applied. The exergy efficiency and influence of design and operational parameters on exergy losses are determined for each of the proposed system configurations. The obtained results represent the background for advanced exergy-based analyses, including thermo-ecological cost.

Life cycle assessment of an integrated oxy-fuel combustion power plant with CO2 capture, transport and storage ‒ Poland case study

The consumption of non-renewable primary energy resources results in their depletion, which is becoming absolutely crucial for the sustainable development of humankind. The production of electricity based on burning fossil fuels involves harmful emissions. Thus, the additional consumption of primary energy is required in order to make up for the environmental impact. The of that consumption of primary exergy per unit of useful products is called the index of TEC (thermoecological cost). When the whole life cycle is considered, we have to do with the LC TEC (life-cycle thermoecological cost).The paper presents the concept of a life cycle assessment based on the thermoecological cost implemented in an integrated OFC (oxy-fuel combustion) power plant with CO2 capture, transport and storage. A mathematical model evaluating the LC TEC was applied and the example utilised Polish conditions.The obtained value of the LC TEC of the analyzed CCS (Carbon capture and storage) system (with 90% CO2 emission reduction) is about 22% higher than the average value for polish coal-fired power plants (without CCS). The results of sensitivity analysis concerning LC TEC allow to conclude that the operation phase dominates (over 99.5%), thus the construction, repairs and decommissioning phases for CCS systems could be neglected in further studies concerning the depletion of non-renewable natural resources.

Thermo-Ecological Evaluation of Nuclear Power Plant within the Whole Life Cycle

Polish energy sector is mainly based on coal combustion, which is responsible for increasing the CO2 emission. Simultaneously, European trends toward sustainability and global warming mitigation will lead to significant changes in the structure of electricity generation in Poland. Due to the domestic energy policy the increase of renewable resources utilisation, as well as installation of first nuclear power units (3x1.6 GWel), are planned in the perspective of the year 2030. The comparison of nuclear power plant with the existing coal ones requires the evaluation within the whole life cycle as well as the application of the common measure of the consumption of natural resources. Both requirements are fulfilled in the case of Thermo-Ecological Cost (TEC) analysis. TEC was introduced by Szargut and expresses the cumulative exergy consumption of non-renewable resources burdening the final consumed goods, e.g. electricity. Moreover, TEC takes into account the additional non-renewable exergy consumption required for mitigation of environmental losses caused by rejection of harmful waste products. In the paper, the TEC algorithm adopted for nuclear power plant is presented. In this case, the whole life cycle includes the following phases: 1) mining and milling, 2) conversion of fuel, 3) enrichment (diffusion or centrifuge), 4) fuel fabrication, 5) plant construction, 6) plant operations, 7) waste management, 8) plant decommissioning and 9) transport. The obtained results are compared with the average TEC index for the Polish energy mix. The direct exergy analysis shows that the direct exergetic efficiency of existing nuclear power unit is about 10% points lower than that of typical coal power unit. However, the TEC analysis proved that in the whole life cycle of the resource utilisation the exergetic efficiency is significantly lower in the case of the nuclear fuel cycle. The main cause of this imperfection appears in the stage of conversion, enrichment and nuclear fuel fabrication.

Thermoecological cost of electricity, heat and cold generated in a trigeneration module fuelled with selected fossil and renewable fuels

The paper presents a thermoecological evaluation of a trigeneration module based on an Internal Combustion Engine fuelled with selected fuels of various origin: domestic/mixed-origin natural gas, CMM (coal mine methane) and biogas. The generated products comprise: electric energy, heat available in hot water and cold generated in an absorption chiller. Transformations of energy and exergy in the trigeneration module have been analysed, and the TEC (thermoecological cost) of the products has been determined. The decomposition of TEC into the cost of resources, the contribution of process irreversibility and the equivalent cost of noxious substances has been shown. The chosen gaseous fuels reflect four different cases: a fossil, non-renewable resource (1 – domestic, 2 – mixed origin) 3 – a by-product from the extraction of a fossil resource and 4 – a renewable resource. It has been demonstrated how the TEC of final products depends on the chosen resource, on the process irreversibility, and on the waste contribution. TEC of electricity produced in the trigeneration module varies from 0.30 (biomass syngas) to 3.11 (mixed origin natural gas), and the TEC of the generated heat and cold varies from 0.61 to 6.46 (heat) and 3.37 and 35.5 (cold) accordingly.

Thermo-ecological cost of hard coal with inclusion of the whole life cycle chain

Fossil fuels are still the dominant source of energy in most economic sectors worldwide, particularly in the electric power sector. The transformation and usage of primary energy are connected with various unfavorable environmental effects. Mainly they are as follows depletion of constrained resources of non-renewable energy, emission of harmful wastes to the environment, emission of GHG (greenhouse gasses). To investigate these effects variety of methods have been developed, the LCA (Life-Cycle Assessment) is one of them. It has emerged as a valuable decision-support tool for both policy makers and industry in assessing the cradle-to-grave impacts of a product or process. Despite many advantages of LCA, it is unfortunately characterized by the lack of inclusion of thermodynamics law, especially second law, which is the basic physical law deciding on the resource economy in any production process. In the paper, the LCA methodology together with TEC (Thermo-Ecological Cost) is proposed to apply for exergo-ecological evaluation of fossil fuels. TEC expresses the cumulative consumption of non-renewable exergy connected with the fabrication of any useful product with additional inclusion of the consumption resulting from the necessity of compensation for environmental losses caused by the removal of harmful substances to the environment. The calculations of TEC of coal are based on the material balances of the whole chain of the production process from mine to the end-user. Within the chain in the coal mine the following sub-processes have been distinguished: preparation of the coal deposit layer for exploitation, exploitation of coal deposits, mechanical processing and enrichment of coal, ventilation of coal mine, transport, energy management of coal mines, compressed air management in coal mines and utilization of methane released during mine exploitation. Besides the processes in the mine, the end use is investigated. For this reason, the different types of coal are assigned for typical users. The potentially negative influence of utilization of coal with inclusion from cradle to grave assessment are examined on the basis of TEC evaluation.

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 Assessment Of Auxiliary Fuel Injection Into Blast-Furnace

Abstract Metallurgy represents complex technological chain supplied with different kinds of primary resources. Iron metallurgy based on blast-furnace process, dominates in world steel production. Metallurgical coke is the basic fuel in this case. Its production is connected with several environmental disadvantageous impacts. One of them is the extended production chain from primary energy to final energy. The reduction of coke consumption in the process can be achieved e.g. by injection of auxiliary fuels or increasing the thermal parameters in the process. In present injection of pulverised coal dominates while recirculation of top-gas seems to be future technology. However, the latter one requires the CO2 removal that additionally extended the production chain. The evaluation of resources management in complex energy-technological systems required application of advanced method based on thermodynamics. In the paper the system exergo-ecological assessment of pulverised coal injection into blast-furnace and top-gas recirculation has been applied. As a comparative criterion the thermo-ecological cost has been proposed.