Steam Source Research Articles

Energy and Environmental Aspects of the Sustainability of Clothing Production

The textile and clothing industries are very often lumped together when it comes to the environmental aspect such that the negative connotation of the textile industry from an environmental aspect is automatically transferred to the clothing industry. However, the two industries should be considered separately, particularly with regard to the machinery used and energy consumption in the production process. The energy consumption of electricity, compressed air, vacuum, steam, and other energy sources in the clothing industry is low compared to other related industries. Furthermore, no carcinogenic and allergenic waste is generated during the production of clothing, which has a low carbon footprint, i.e., it practically does not pollute the air, soil, and water. The waste produced during cutting is clean and unused and is immediately recycled. All of this contributes to the sustainability of the clothing industry from the energy and environmental aspects. This article describes the cutting and joining techniques used in the manufacture of clothing, from the energy and environmental aspects as well as aspects of the weaves, the necessary machine elements and mechanisms, and the energy used in all joining techniques, from which the above claims and facts can be seen.

Good team players? The impact of team member knowledge, skills and abilities on sourcing teamwork and sourcing task-work effectiveness

PurposeThe aim of this paper is to enhance understanding of the use of sourcing teams (STs) by organisations in their procurement and supply chain management. The paper achieves this by exploring, within the context of the supply chain directorate of a global aerospace manufacturing company (GAMC), both the relationship between sourcing teamwork effectiveness (TE) and sourcing task-work effectiveness (TA) and the relationship between individual team member knowledge, skills and abilities (KSAs) and TE.Design/methodology/approachThe authors develop a theoretical model positing positive links between both KSAs and TE and TE and TA. The model is empirically validated using partial least squares structural equation modelling in a survey of 108 ST members from a GAMC.FindingsThe authors identify that, within GAMC, four of five KSAs drive TE and further discover the direct effects of TE on improved TA. Additionally, the authors observe within GAMC the indirect effects of KSAs on TA cascading through TE.Research limitations/implicationsLimitations include the use of a single firm and self-report measures for data collection. In spite of this, the paper has numerous research implications. Previous research on STs has combined factors related to TE and TA. In this paper, TE and TA were disaggregated, and the relationships between them were explored. The relationships were found to be positive within GAMC, a finding that strengthens the evidence base supporting the use of STs by organisations in their procurement and supply chain management. In addition, the paper also strengthened the evidence base regarding the importance of KSAs to TE, which complements existing research highlighting the importance of team-level factors and individual technical attributes.Practical implicationsThe findings from GAMC suggest that executives/managers should take an individual as well as a team-level perspective when developing STs and should consider KSAs as well as technical knowledge when judging individuals’ suitability for inclusion within an ST. There are established KSA tests in the literature that could be used by managers for this task. The findings also inform executives/managers that TE matters for TA and needs attention and investment, especially where sourcing tasks concern high-value areas and/or critical incidents within supply chains.Originality/valueTo the best of the authors’ knowledge, this is the first paper to explore the relationship between TE and TA. Establishing that this relationship is a positive one provides critically important evidence regarding the efficacy of STs, which are widely used within procurement and supply chain management. It is also a rare study looking at TE from the perspective of individual team member KSAs, with further positive relationships revealed. Both findings enhance what is a very limited literature on a widely used practice within procurement and supply chain management.

Integrated CO2 capture and conversion into methanol units: Assessing techno-economic and environmental aspects compared to CO2 into SNG alternative

Using carbon dioxide (CO2) as a raw-material to produce value-added chemicals has a strategic role to play in the decarbonization of energy resources and the transition to a climate-neutral economy. E-methanol, Synthetic Natural Gas (SNG) and e-kerosene are one of the most promising pathways to convert CO2. In this context, the aim of this work is to propose an optimized and integrated CO2 to methanol process and then to compare it to the CO2 to SNG process from economic and environmental points of views. An optimized reactor configuration in the CO2 to methanol conversion unit has been successfully implemented in Aspen Plus® and leads to a thermal energy self-sufficiency of this unit. A heat integration with an advanced capture unit has been performed where 5 % of the heat requirement could be provided from the conversion unit while 95 % come from external steam source. Techno-economic assessment of the optimized process showed that methanol is more profitable when it is used as a raw material to synthetize other chemicals. As an energy carrier, SNG is more interesting. Compared to the reference scenario, a net CO2 emission reduction of 70 % in the CO2 to SNG route and of 60 % in the CO2 to methanol route were obtained. Concerning the fossil depletion impact, in both cases, a reduction of more than 60 % was noticed (ca. 75 % in CO2 to SNG route and 61 % in CO2 to methanol case).

Citric acid steam-assisted decomposition method for the synthesis of meso-macroporous magnesium oxide with rich oxygen defects: Efficient removal and convenient recovery property of Congo red and Ni(II)

The removal of Congo red (CR) and heavy metal ion nickel (Ni(II)) from wastewater is a critical concern for safeguarding the aquatic environment and promoting sustainable development. Herein, a novel citric acid steam-assisted decomposition method is applied to form meso-macroporous magnesium oxide (MgO) with rich oxygen defects. As the gelation process of xerogel precursor could be significantly promoted by the steam-assisted process with citric acid solution as steam source, the morphology structure of MgO changes into loose aggregates with sharp edges and is covered by a layer of MgO nanoparticles. The synthesized MgO, with a high surface area (103.60 m2 g−1), meso-macroporous structure and abundant oxygen defects, exhibits super adsorption capacities for CR (7109.85 mg g−1) and Ni(II) (1405.88 mg g−1). The MgO (0.4 g L−1) could completely remove CR (200 mg L−1) in 30 min, while 10 min for Ni(II) (200 mg L−1) adsorption. The adsorption mechanism of MgO for CR and Ni(II), including electrostatic interaction, oxygen vacancy capture, hydrogen bonding and ion exchange, is effectively enhanced due to the appearance of meso-macroporous structure and oxide defects, such as 5-coordinated oxygen anion (O5C2−) for terrace, 4-coordinated oxygen anion (O4C2−) for edge and 3-coordinated oxygen anion (O3C2−) for corner. The easy calcination is applied to recycle MgO after CR adsorption and the CR removal efficiencies are above 98 % after five cycles. Meanwhile, a nickel chelator (Na2EDTA) and calcination are used to regenerate the MgO after Ni(II) adsorption and the adsorbent shows an insignificant removal efficiency loss after three cycles. The meso-macroporous MgO with rich oxygen defects has the characteristics of high adsorption speed, high adsorption capacity and convenient recovery property, and is expected to become an ideal material for the rapid treatment of high concentration wastewater.

Study on time-of-use pricing method for steam heating system considering user response characteristics and thermal storage capacity

Industrial steam heating is a significant aspect of energy consumption in China, playing a crucial role in industrial energy efficiency. Historically, demand response research has predominantly focused on the electricity sector, with limited emphasis on steam supply. This study explores a novel Time-of-Use pricing approach for steam heating systems, anchored in the demand response theory of price incentives. It develops a peak-valley segmentation method by considering both the load differences between supply and demand and the thermal storage capacity of the pipeline system. Additionally, the paper delves into user response characteristics to formulate an optimized Time-of-Use pricing model for steam heating systems. Implemented in a Jiangsu-based case study, the model demonstrates significant efficiency improvements: it reduces the peak-valley load difference by up to 68.3% and cuts steam purchasing costs by ¥135,000. Furthermore, the alignment between the users' total steam load curve and the heat source's steam supply is enhanced by 18.8%, illustrating the model's effectiveness in balancing demand and supply.

A novel system for reducing power plant electricity consumption and enhancing deep peak-load capability

Enhancing the operational flexibility of coal-fired power plants is a crucial measure for energy transition. Current heat-power decoupling technologies primarily rely on external heat storage or provision. In order to comprehensively analyze the self-decoupling potential of the units and explore more effective methods to reduce the power plant electricity consumption rate (PPEC), this study proposes an innovative system that utilizes surplus steam from the power plant to drive rotating equipment through multi-stage series-parallel turbines. The study investigates the impact of various steam sources, methods of electrical equipment connection, and exhaust positions on system performance. The results demonstrate that the optimal strategies can lead to an average reduction of PPEC to 2.84%, decrease the power supply coal consumption rate by an average of 12.04 g/kWh, and increase the deep peak-shaving capacity by 35.20 MW during the heating season. During the non-heating season, it can reduce the PPEC by an average of 3.73% and increase the deep peak-shaving capacity by 30.47 MW. The static investment payback period and dynamic investment payback period under the optimal strategy are 5.15 years and 6.09 years, respectively. This research presents a promising approach to enhancing the flexibility of thermal power units by utilizing small steam turbines.

Selecting the Startup Option for the Surgut GRES-2 800-MW Power Unit in the Absence of Its Own Steam Source

Selecting the Startup Option for the Surgut GRES-2 800-MW Power Unit in the Absence of Its Own Steam Source

An Ejector and Flashbox-Integrated Approach to Flue Gas Waste Heat Recovery: A Novel Systematic Study

In this study, a comprehensive examination was conducted to explore the technology involved in the recovery of waste heat from flue gas emitted by a 1000 MW unit. Traditional methods are constrained in their ability to harness waste heat from flue gas solely for the purpose of generating medium-temperature water. The system being examined not only recovers waste heat but also utilizes it to generate steam, thereby greatly improving resource efficiency. The process entails utilizing the flue gas to heat water to a certain temperature, followed by subjecting it to flash evaporation. This process leads to the generation of low-pressure waste heat steam. Within the steam ejector, the waste heat steam combines with high-pressure motive steam extracted from the source, resulting in the formation of medium-pressure steam. Within the steam ejector, the waste heat steam blends with high-pressure motive steam drawn from the source, forming medium-pressure steam that eventually feeds into the A8 steam extraction pipe (low-pressure turbine pumping pipe). The present study examines the fluctuation patterns in motive steam flow, suction coefficient, waste heat steam volume, and outlet temperature of the flue water heat exchanger when different motive steam sources are used. Additionally, the research calculates the reduction in CO2 emissions, the coal consumption for power supply, and the cost savings in fuel for the retrofitted system. The findings indicate that maximizing energy utilization can be achieved by operating the retrofitted unit at the lowest feasible waste heat steam pressure. The implementation of the new system has resulted in a substantial decrease in coal consumption for power supply. When employing main steam as the extraction steam source, the consumption of coal for power generation decreases in proportion to the decrease in waste heat steam pressure while maintaining a constant unit load. When the waste heat steam pressure reaches 0.0312 MPa, the recorded coal consumption for power generation varies between 289.43 g/kWh at 100% turbine heat acceptance (THA) and 326.94 g/kWh at 30%THA. When comparing this performance with the initial thermal power plant (TPP) unit, it demonstrates reductions of 2.26 g/kWh and 1.52 g/kWh, respectively. After implementing modifications to this 1000 MW unit, it is projected that the annual CO2 emissions can be effectively reduced by 6333.97 tons, resulting in significant cost savings of approximately USD 0.23 million in fuel expenses. This system exhibits considerable potential in terms of emission reduction and provides valuable insights for thermal power plants aiming to decrease unit energy consumption.

Investigation on the performance of EDA-based blended solvents for electrochemically mediated CO2 capture

EDA-Cu based electrochemically mediated CO2 capture method was developed as a promising technology to substitute the conventional amine-based CO2 capture, especially in industries without available steam source. However, the highly corrosive and poor Cu cycling performance seriously obstruct its large-scale application. In this work, traditional primary amine, secondary amine and tertiary amine (MEA, DEA and TEA) are chosen to blend with EDA to alleviate the problems of EDA. Electrochemical measurements, corrosiveness comparison, CO2 absorption and desorption performance were conducted to investigate the advance performance of proposed blended solvents comprehensively. The corrosion potential in all the mixtures is significantly higher than that in sole EDA solution, which illustrates that the corrosiveness of proposed mixed solvents to Cu electrode is weaker. Besides, the Cu cycling performance is greatly improved and the energy consumption is significantly reduced by using blended solvents. Overall, 50/50 EDA/MEA mixed solution with high CO2 capacity and fast absorption rate is suggested to be a substitute for traditional EDA solvent. The CO2 desorption energy consumption of 50/50 EDA/MEA mixed solution decreases 14% than that of EDA solution at a current density of 0.01 A/cm2. Meanwhile, the copper cycling performance is also improved in 50/50 EDA/MEA mixed solution as the cathode Faraday efficiency (CFE) increased from 43% (EDA) to 53% (50/50 EDA/MEA). Results show that the proposed mixed amine solvents lead to the successful circumvention of highly corrosive and poor Cu cycling performance in the electrochemically mediated CO2 capture system, which will contribute to the exploration of efficient blended solvents for EMAR CO2 capture process and promote its industrial application.

Working condition expansion and performance optimization of two-stage ejector based on optimal switching strategy

Ejectors are widely used as steam power cycle components to recover superfluous water vapor. However, in a system for preparing distilled water used for pharmaceutical injection, the ejector periodically deviates from the design condition owing to fluctuations in steam source pressure. In particular, when the pressure is reduced to approximately 75% of the design value, performance is significantly degraded, affecting water production efficiency. To solve this problem, a two-stage ejector with control switching strategy is proposed in this paper. The performance of a series of two-stage ejector structures with different scale ratios was analyzed, and the optimum scale ratio was determined. Furthermore, an optimal switching strategy is devised to ensure that the two-stage ejector maintains stable performance under different primary flow pressures. The numerical results indicate that the entrainment ratio of the two-stage ejector is 79.4% higher than that of the single-stage ejector when the pressure is 60% of that of the designed primary flow. Moreover, the two-stage ejector can maintain satisfactory entrainment performance when the traditional ejector enters reversed mode under 50% of the designed pressure. The experimental results show that the entrainment performance of the proposed two-stage ejector can be improved significantly when power fluid pressure is insufficient.

Healthcare Consumerism and Patient Loyalty in the Age of Telehealth: An Exploratory Roadmap

Customer loyalty is known as a source of sustained revenue steam and means of building and maintaining a strong relationship with customers for lifetime shopping experiences. Although there are a few studies in patient loyalty in healthcare fields, there is no theoretical or empirical studies on patient loyalty under the telehealth environment. This study, therefore, borrowed the framework from the commercial consumer loyalty model and build patient loyalty framework for healthcare practices in telehealth environment. There is a growing trend in both academic and industry circles that telehealth will stay as a one of the viable healthcare management alternatives even after Covid period. This study reviews the current status of patient loyalty based on the existing literature and explores a pathway to establish patient loyalty in telehealth platform.

Preliminary analysis of the reliability of NPP auxiliary needs backup based on a multifunctional steam turbine and a start-up boiler house

NPP start-up boiler houses can be used to reserve the station’s own needs and increase its economic efficiency when used together with an additional steam turbine. The result is achieved due to the fact that a multifunctional steam turbine can provide power supply for the NPP’s own needs by using the afterheat of the reactor core. The start-up boiler house can be a reserve source of steam for a multifunctional steam turbine. At the same time, the multifunctional turbine in combination with the start-up boiler house can effectively operate in the normal mode to generate additional electricity for the power system. In this article, the reliability of the auxiliary needs reserve of nuclear power plants based on a multifunctional steam turbine and a start-up boiler house has been investigated. The economic effect of improving NPP safety is calculated as an annual reduction in the risk of damage from accidents with damage to the reactor core.

A simple approach to fabricate protective coatings on the surface of AZ91 alloy and its corrosion resistance

In this paper, the corrosion resistant coatings were fabricated on AZ91 Mg alloy by steam treatment using deionized water as a steam source. The treatment temperature was maintained at 150 ℃, while the treatment time was varied at 3, 6 and 9 h. The results showed that relatively dense steam coating can be formed on the surface of AZ91 alloy by steam treatment for 3-9 h, and the phase structure of steam coating was mainly composed of Mg(OH)2 and contained AlO(OH) and Mg-Al LDH. With the extension of the steam treatment time, the better the corrosion resistance of the steam coating, and the corrosion current density was as low as 10-7~10-8 A·cm-2, which was 3-4 orders of magnitude lower than AZ91 Mg alloy substrate (~10-4 A·cm-2).

Steam-mediated foliar application of catechol and plant growth regulators enhances the growth attributes, photosynthesis, and essential oil production of lemongrass [Cymbopogon flexuosus (Steud.) Wats

Improvement in growth, yield, and essential oil production of plants through foliar application of PGRs and elicitors has been extensively studied in the authors' laboratory. Instead of using a sprayer machine, a new steam-spray method was applied to explore the possibility that if we could increase the growth, yield, and EO production of lemongrass. The foliage of lemongrass was steam-sprayed five times with 5 × 10−6 M of catechol and PGRs, viz. Indole acetic acid (IAA), kinetin (Kn), 6-benzyl aminopurine (BAP), salicylic acid (SA), triacontanol (TRIA), and ethrel at 90 days after transplantation (DAT). The steam spray was carried out using a calculated distance between the steam source and plant foliage so that the steam jet might not damage the plants. Lemongrass EO was extracted by Clevenger's method and then analyzed using GC-MS. All the parameters were studied at 150 DAT. The steam spray of SA and catechol proved the best for most of the parameters studied. Compared to the control, the application of SA enhanced the plant's fresh and dry weight by 26.1% and 43.4% and the total content of chlorophyll and carotenoids by 52.6% and 62.8% respectively, and chlorophyll fluorescence (Fv/Fm) by 15.2%. Catechol significantly improved the content (350%) and productivity (433.3%) of lemongrass essential oil, but it decreased the proline content (25.0%). SA treatment increased the content of active constituents of EO viz., neral and geranial, by 65.7% and 59.6%, respectively. After SA and catechol, the application of IAA also resulted in promising values for most parameters.

Superheated steam similarity simulation on longitudinal distribution of maximum smoke temperature rise in tunnel fires

• The superheated steam is used to simulate the migration and heat transfer process of fire smoke. • The similarity between fire smoke and superheated steam motions is demonstrated. • The maximum steam temperature rise is related to buoyant flux and tunnel height. • A calculation model for predicting the longitudinal distribution of maximum smoke temperature is developed. Physical simulation of smoke migration and temperature evolution is an important measure for studying tunnel fires. In this work, based on the similarity theory of fluid dynamics, the motion of superheated steam in the air is used to simulate the migration and heat transfer process of high-temperature smoke generated by tunnel fires. The similarity criteria and similarity scales between the motion of superheated steam and fire smoke are derived by the similarity transformation method. The migration pattern and temperature evolution of superheated steam under natural ventilation are investigated by using a self-built superheated steam experimental system. Then, fire tests are conducted on a combustion wind tunnel to verify the feasibility of this method. The results show that the similarity between fire smoke and superheated steam motions is demonstrated by considering geometric conditions, kinematic conditions and dynamic conditions. The maximum steam temperature rise increases as a power function of the buoyant flux and depends on the 5/3 power of the tunnel height. Moreover, the maximum ceiling steam temperature rise attenuates exponentially with the increasing distance from the steam source. Finally, the calculation model for predicting the longitudinal distribution pattern of the maximum smoke temperature rise beneath the tunnel ceiling is developed, which agrees well with the experimental results.

Classical and Process Intensification Methods for Acetic Acid Concentration: Technical and Environmental Assessment

This study aims to investigate, from a technical and an environmental perspective, various alternatives for acetic acid concentration for maximizing acetic acid production, its purity, and in the meantime, minimizing the energy usage and the environmental impact. Liquid–liquid extraction followed by azeotropic distillation using different solvents such as: (i) ethyl acetate, (ii) isopropyl acetate, and (iii) a mixture containing isopropyl acetate and isopropanol were first explored, using process flow modeling software. The three cases were compared considering various technical key performance indicators (i.e., acetic acid flow-rate, acetic acid purity, acetic acid recovery, power consumption, thermal energy used, and number of equipment units involved) leading to the conclusion that the usage of the isopropyl acetate—isopropanol mixture leads to better technical results. The isopropanol-isopropyl acetate mixture was furthermore investigated in other two cases where process intensification methods, based on thermally coupled respectively the double-effect distillation process, are proposed. The highest quantity of pure acetic acid (e.g., 136 kmol/h) and the highest recovery rate (e.g., 97.74%) were obtained using the double-effect method. A cradle-to-gate life cycle assessment, involving ReCiPe method, was used to calculate and compare various environmental impact indicators (i.e., climate change, freshwater toxicity potential, human toxicity, etc.). Several steam sources (i.e., hard coal, heavy fuel oil, light fuel oil, natural gas, and biomass) were considered in the environmental evaluation. The results of the life cycle assessment show a reduction, by almost half, in all the environmental impact indicators when the double effect method is compared to the thermally coupled process. The usage of biomass for steam generation lead to lower impacts compared to steam generation using fossil fuels (i.e., hard coal, heavy fuel oil, light fuel oil, natural gas).

Thermodynamic analysis of supercritical water gasification combined with a reversible solid oxide cell

The low cost of electricity in some areas facilitates the adoption of high-temperature electrolysis plants for the large-scale storage of electricity. Supercritical water gasification (SCWG) is a promising method of syngas production from wet biomass. Additionally, it is a potential source of steam for electrochemical plants. However, the commercialisation of standalone SCWG systems is hindered by low efficiency and high operating cost. Accordingly, we propose the integration of SCWG with a reversible solid oxide cell (rSOC) to realise simultaneous syngas or power generation and wet biomass conversion. This technique would make the process feasible in terms of energy, allowing engineers to use SCWG to combine power generation with fuel production. The wet syngas from the SCWG is fed to the rSOC powered by excess renewable electricity in electrolysis mode, where steam is reduced to H2 to produce dry syngas with a higher calorific value. The energy efficiency of the proposed system is 91% in electrolysis mode and 47% in fuel cell mode. The electrolysis increases the syngas yield by a factor of thirteen and the use of total syngas generates twelve times more power in fuel cell mode compared to the use of only fresh syngas from SCWG.

ANALISIS pH, TDS, TOTAL HARDNESS, ALKALINITY, DAN SILICA PADA BOILER FEET WATER DI PT. SOCFINDO PERKEBUNAN KELAPA SAWIT DI SEUNAGAN

The basic need of living things that is very important and cannot be separated is water. Various industrial activities require water for processing activities such as the palm oil industry, the palm oil industry is required to use water with good conditions such as proper chemical treatment. The power plant at PT. Socfindo Seunagan, requires water for steam needs from the boiler. Boiler is a closed place to produce steam from heating water. The boiler system, among others, consists of 3 parts, namely the water line system and steam system, fuel system and boiler system. Part of the steam system requires a lot of water to be adjusted automatically so that the steam in the system is met. The boiler feed water used must be able to meet the requirements as a source of steam and can prevent the formation of corrosion in the pipes. Therefore researchers are trying to maintain the stability of boiler feed water by maintaining pH, therefore it is necessary to analyze pH, TDS, Total hardness, Alkalinity, and SILICA in boiler feed water.

Needle shaped conductivity probes with integrated micro-thermocouple and their application in rapid condensation experiments with non-condensable gases

Abstract The present paper deals with advanced conductivity probes for local void measurements, which were equipped with a microthermocouple, which is integrated into the probe at the place of the electrode wire. These probes were used for rapid transient condensation tests in a heat exchanger pipe immersed into a cooling water tank. The experiments serve as data sources for the validation of thermal-hydraulic system codes concerning the modelling of the condensation, particularly with respect to the behaviour and effect of non-condensable gases. The present tests were carried out at the pressurizer test facility DHVA of the University for Applied Sciences in Zittau/Görlitz, IPM serving as steam source. The slightly downwards inclined condensation tube was connected to the head of the pressure vessel and supplied with steam in this way. The application of a new type of two-phase instrumentation has revealed details about the transient condensation process. Since tests were performed with and without the presence of a non-condensable gas (air), the effect of the gas could be studied. The merits of the probes lie in the ability to distinguish between steam and gas. Without the synchronous temperature and void measurement performed by the probes it would have not been possible to clarify the physical background of the temperature jumps found during the experiments with the non-condensable gas.

A study on solid oxide electrolyzer stack and system performance based on alternative mapping models

In this study, a solid oxide electrolyzer cell (SOEC) stack model is developed based on an alternative mapping concept. The SOEC stack performance in a commercial hot box is systematically studied under different operating currents, flow rates, and flow directions. The results revealed that the SOEC stack operated in a hot box has thoroughly different temperature distributions, resulting in additional efficiency losses and an increase in thermal neutral voltage. The SOEC stack model computation results are summarized into stack performance diagrams and used in the system design. A 6-Nm 3 /h SOEC system with preheaters and recycling cathode materials is designed, and its performance is studied. The system efficiency is greatly influenced by the steam generator, and an external steam source can help increase the total efficiency of the system to more than 83%. Even the current increase may deteriorate the stack performance. It can increase the SOEC system efficiency by saving energy in the steam generator and preheaters. An increase in the flow rate around anode and cathode can improve the system capacity and efficiency. The system's maximum capacity is limited by the preheater heat balance and the stack output temperature. The feasible maximum system capacity is 33.4 kW electrolysis electric power input and 9.93 Nm 3 /h hydrogen production rate. At a constant system capacity, decreasing the air flow rate can minimize the heat losses in anode off-gas and achieve more than 87% nonsteam system efficiency. • A new SOEC stack modeling method based on the alternative mapping concept. • The differences of the stack performances in lab scale test and commercial installation circumstances are fully discussed. • A 6 m 3 /h SOEC demo system is designed and analyzed to get the best capacity and efficiency.