Reduction In Gas Consumption Research Articles

Homoepitaxial growth of device-grade GaAs using low-pressure remote plasma CVD

We have achieved the growth of high-quality, homoepitaxial 100 GaAs thin films at 0.5 mbar and 500 °C using a Remote Plasma Chemical Vapor Deposition (RP-CVD) reactor. With this process, we demonstrate a film growth rate up to 3 μm/h, comparable to the conventional MOCVD technique. The resulting films exhibit structural characteristics close to those of commercial GaAs wafers, with excellent crystalline quality as confirmed by SAED patterns and XRD rocking-curve measurements for the 004 peak with a FWHM of 0.004°. AFM measurements reveal a surface roughness of 0.2 nm, similar to that of a polished wafer. Analysis of the chemical composition – as determined through XPS surface and depth-profiled measurements – indicates that the film is homogeneous, with a constant III/V ratio of 1 throughout the whole layer, and has no detectable carbon or oxygen contamination. Additionally, the films demonstrate a sharp photoluminescence peak (FWHM of 55 meV), a p-type doping concentration of 1.1018 cm−3, and a hole mobility of 172 cm2 V⁻1.s⁻1. This work thus demonstrates a cost-effective growth method for III-V devices, enabled by the reduced gas consumption (only a few sccm, compared to tens of L/min in MOCVD) in RP-CVD operation at low pressure.

Analysis of the Rebound Effect and Induced Effect of Non-residential Natural Gas Consumption: Empirical Evidence from China

Following the Paris Agreement, economic development demands energy services while reducing emissions. This study focuses on non-residential natural gas consumption, which plays a crucial role in transforming the energy sector; however, market-based mechanisms are still in the early stages and have not yet been explored. Based on the analysis of data collected from 2000 to 2020 in China, this study constructs a simultaneous equation model to analyze the rebound and induced effects of non-residential natural gas consumption. This paper finds that industrial economic growth has a significant promoting effect on non-residential gas consumption. In addition, implementing and promoting natural gas utilization policies and increases in natural gas prices can significantly reduce gas consumption intensity. This article innovatively calculates the rebound and induced effects of non-residential gas consumption, providing a decision-making reference for accelerating the realization of the dual-carbon goal.

High-fidelity model development of CO2 booster refrigeration systems in supermarkets using field measurements

Supermarket refrigeration systems adopting traditional refrigerants with high global warming potential (GWP) have impacts on global warming for indirect and direct greenhouse gases (GHG) emissions. CO2 is a popular low-GWP alternative. The transcritical operation of CO2 systems worsens their energy performance, but provides recoverable heat as a heat source to reduce gas consumption. To evaluate operation performance, data-driven models, trained by historical data, are weak in implementation with datasets outside the scope of training data; in contrast, theoretical models have better extrapolation ability to calculate all operation conditions of CO2 systems at supermarket. Existing theoretical modeling approaches often lack validation against the limited public-access data, which reduces model reliability for further applications, and adopt oversimplified inference methods for unmeasured variables, which increases the risks of breaking thermodynamic laws and lowering model accuracy. This study therefore develops a steady-state theoretical model for CO2 booster refrigeration systems validated against field measurements from three UK supermarkets. The available measurements are utilized to the best level to ensure model accuracy and physical interpretability. Proposed methods to infer missing variables in CO2 systems include condenser outlet temperature, evaporating temperature, compressor isentropic efficiency and compressor mass flow rate. Results show that proposed inference methods enhance the abilities of the proposed modelling approach to ensure data integrity, avoid breaking thermodynamic laws, and improve model accuracy by reflecting real-time actual values of unmeasured variables rather than rough assumptions. The proposed modeling approach provides satisfactory accuracy validated using high-resolution measurements across the whole year from three real supermarkets.

IDENTIFICATION OF OPERATING MODES OF THE DEFROSTING GARAGE OF THE LOAD STATION OF THE INDUSTRIAL ENTERPRISE IN DYNAMIC CONDITIONS

Purpose. At the current stage of operation of the defrosting garages of the freight station of the industrial enterprise, the defrosting of wagons with bulk raw materials takes place in conditions of a changing environment, which leads to low efficiency of the interaction of railway transport and the unloading complex. To solve this problem, it is necessary to identify the modes of operation of the defrosting garages of the cargo station of the industrial enterprise in dynamic conditions, to analyze the consumption of natural gas for defrosting. Research methods. The following methods were used during the research: synthesis and analysis for the study of the issue and scientific publications regarding the state and ways of identifying the modes of operation of the defrosting garages of the cargo station of the industrial enterprise; experiment planning - to obtain a multidimensional, diverse array of statistical data; theory of probability and mathematical statistics - for data processing, obtaining correlation dependences of indicators of identification of modes of operation of defrosting garages of a cargo station of an industrial enterprise in dynamic conditions. The results. The work is devoted to the solution of the scientific and technical problem of identifying the operating modes of the defrosting garages of the cargo station of the industrial enterprise in the conditions of a changing environment. The work evaluates the modes of operation of the defrosting garages of the cargo station of the industrial enterprise when defrosting bulk raw materials.The influence of external factors on the consumption of natural gas during defrosting of bulk raw materials in wagons was evaluated. On the basis of research conducted in the process of defrosting bulk raw materials in wagons, two temperature modes of operation of garages were identified, which determine different gas consumption. Basic, regulatory mode with a constant defrosting temperature set by technological standards and maximum gas consumption. Periodic, with reduced gas consumption, is characterized by a decrease in temperature after 6-7 hours and subsequent defrosting using accumulated heat, which ensures a decrease in gas consumption. The possibility and expediency of wide practical use of accumulated heat in the process of defrosting bulk raw materials in wagons has been established. The temperature and time parameters of the process of defrosting bulk raw materials in wagons using accumulated heat are proposed, which ensures a significant reduction in energy consumption. Increasing the efficiency of the defrosting garages of the freight station of the industrial enterprise was achieved on the basis of the development of a method and model of natural gas consumption when defrosting bulk raw materials in wagons using accumulated heat. The scientific novelty consists in the identification of the operating modes of the defrosting garages of the cargo station of the industrial enterprise in the conditions of a changing environment, which is based on a multidimensional, diverse array of experimental data. Practical significance.The presented theoretical provisions regarding the modes of operation of the defrosting garages of the freight station of the industrial enterprise made it possible to develop a method and model of natural gas consumption during defrosting of bulk raw materials in wagons using accumulated heat.

Assessment of the impact of setting the heating curve on reducing gas consumption in a residential building while ensuring thermal comfort

Due to the large share of the residential building sector in CO2 emissions, it is necessary to look for quick-to-implement and cost-free solutions for heating systems aimed at increasing their efficiency and reducing fuel consumption. The aim of the study is a multi-aspect assessment of the proper setting of the heating curve in the weather controller of a low-temperature floor heating system with a condensing gas boiler, and an analysis of the impact of the heating curve slope on the natural gas consumption, the emission of gaseous and dust pollutants and on maintaining appropriate indoor air parameters: air temperature, operative temperature and PMV and PPD. A wide range of simulation tests were carried out using the TRNSYS software for an existing energy-efficient single-family residential building, with mechanical ventilation with heat recovery, located in north-eastern Poland in Bialystok. Changing the heating curve slope by 0.1 can reduce gas consumption and pollutant emissions by 1.6–10.3 %. Low heating curve slopes may result in failure to reach the temperature set by users (difference between the set and achieved indoor temperature up to 1.9 K), while maintaining standard thermal comfort parameters (−0.5<PMV<+0.5; PPD<10 %). Reducing the indoor air temperature by 2 K can contribute to reducing gas consumption by 11 % while maintaining standard thermal comfort parameters. Changing the heating curve slope is one of the effective methods of reducing fuel consumption in the building. Results are useful for users of buildings equipped with low-temperature heating systems with floor heating and installers of these systems.

Operational characteristics of solar-gas combined heating water system with phase change heat storage units for oilfield hot water stations

To achieve the low carbonization heating purpose of oilfield hot water stations, an innovative solar-gas combined heating water system with phase change heat storage (PCHS) units is proposed. The operating characteristics of the combined heating system utilizing PCHS and traditional water heat storage (WHS) are compared. The impact of the phase transition temperature of phase change materials (PCMs) on the operational characteristics is simultaneously investigated. The findings demonstrate that the utilization of PCHS can yield a reduction in gas consumption for the combined heating system by about 7.02 % compared to WHS. Moreover, the combined heating system achieves better energy savings when the phase transition temperature is slightly lower than the heat demand temperature at the load end. The heating demand of gas boilers is reduced by about 75.60 GJ during the summer and autumn when the phase change temperature changes from 80 °C to 62 °C. This study provides theoretical guidance and references for the industrial application of solar heating systems (SHSs) that utilize PCHS units.

Direct growth of highly oriented GaN thin films on silicon by remote plasma CVD

We report on low-temperature (500 °C) and low-pressure (0.3 mbar) direct growth of GaN thin films on silicon (100) substrates using remote plasma chemical vapour deposition (RP-CVD). In the custom-designed reactor, an RF inductively coupled plasma is generated remotely from the substrate’s area to facilitate the decomposition of group-V precursor, N2 with added H2, while group-III precursor trimethylgallium (TMGa), is directly injected into the growth chamber mixed with H2 carrier gas. Growth parameters such as RF power, process pressure and gas flow rates have been optimized to achieve a film growth rate of about 0.6 µm h−1. Several characterization techniques were used to investigate the plasma and the properties of the grown thin films in terms of their crystallinity, morphology, topography, and composition. The films are highly textured with a preferential orientation along the c-axis of the wurtzite structure. They present a small roughness in the nanometer range and a columnar microstructure with a grain size of one hundred nanometer, and a gallium polarity (+c plane oriented). Rutherford backscattering spectrometry and nuclear reaction analysis show that the chemical composition is homogeneous through the depth of the layer, with a III/V ratio close to 1, a very low content of oxygen (below the detection limit ∼1%) and a carbon content up to 11%. It was shown that the increase of plasma power helps to reduce this carbon contamination down to 8%. This research paves the way for a growth method compatible with cost reduction of III–V thin film production achieved through reduced gas consumption facilitated by RP-CVD operation at low pressure.

Enhancing energy efficiency through hourly assessments of passive interventions in educational-office buildings: A case study in a Mediterranean climate

This research explores the impact of passive interventions on various energy consumption parameters and their interdependence to enhance the energy efficiency of a building. While overall outcomes from envelope interventions using passive strategies are positive, a closer examination on an hourly basis reveals certain drawbacks that impede improvements in energy efficiency. A combination of methods is employed, utilizing the gray-box method for input data collection and the white-box method for sensitivity analysis to assess the impact of proposed interventions on building envelope individually and in combination. The building's energy consumption reveals that the combined impact of the passive strategies results in an approximately 82% reduction in gas consumption and a 2% reduction in electric consumption. Sensitivity analysis underscores the necessity of hourly investigations, introducing a research dimension to the study. Hourly assessments expose side effects that hinder the rate of improvement in the envelope retrofitting scenario. Statistical analysis of consumer parameters highlights the significance of the cooling system's hourly consumption, particularly in mitigating undesirable effects during shoulder seasons. By minimizing these side effects, the energy consumption of the cooling system in the envelope retrofitting scenario represent a notable 41.44% reduction, a substantial improvement from the initial 16.16%.

Energy Audits and Energy Modeling as a Tool towards Reducing Energy Consumption in Buildings: The Cases of Two Multi-Unit Residential Buildings (MURBs) in Toronto

This research is based on an energy audit of two multi-unit residential buildings (MURBs) located in Toronto, Canada. Energy consumption (gas and electricity) data were extracted from the energy bills of the two buildings for a consecutive period of three years. The data were then normalized to account for variations in weather conditions. Conclusions were drawn from correlation analyses between kWh, cooling degree days (CDDs), and heating degree days (HDDs), which were then compared to the energy consumption benchmarks of MURBs within the GTA. An energy simulation using e-Quest v.3.64 was performed, utilizing the advantages of the e-Quest building modeling tool to create a virtual 3D model of the audited buildings. A baseline model was constructed to reflect the actual buildings and was used to simulate the outcomes and calculate the projected energy savings from window replacements with a higher energy efficiency than the existing ones. The simulation results revealed that triple low-E glazing outperformed single- and double-glass windows, achieving reductions of 38% and 34% in gas consumption, respectively. The building envelope simulations showed that enhancing insulation reduced gas consumption by 4%, while an insulation upgrade demonstrated no discernible savings. Reducing the window area by 20% (north/south sides) led to a 6% decrease in gas consumption, while a 30% reduction resulted in approximately 9% of energy savings.

Natural gas as a transition bridge by 2035 and its transmission capacities adequacy

ABSTRACT This paper analyzes the potential for natural gas in Austria, the Czech Republic, and Slovakia in order to develop a model that accurately describes the adequacy of transmission capacities in the region up until the year 2035. Two scenarios are created using the model. The first scenario is based on the situation prior to the Russian-Ukrainian conflict, while the second scenario considers the conflict, allowing to observe its impact. In the Original Scenario, gas was an indisputable part of the energy mix, and it was desirable to increase the transmission capacity. In contrast, the Reduction Scenario aims to reduce gas consumption and to diversify the portfolio of suppliers, which makes its role uncertain. Under this scenario the flow distribution significantly changes and neglects the transit role of the selected region. The surprising result was that the flow through Ukraine became the main gas flowing from Russia. Both scenarios also shared a common outcome – the importance of storage capacities.

The Power of Substitution: The Great German Gas Debate in Retrospect

ABSTRACT: The Russian attack on Ukraine in February 2022 laid bare Germany's dependence on Russian energy imports and ignited a heated debate on the costs of a cutoff from Russian gas. While one side predicted economic collapse, the other side (ours) predicted "substantial but manageable" economic costs due to households and firms adapting to the shock. Using the empirical evidence now at hand, this paper studies the adjustment of the German economy after Russia weaponized gas exports by cutting Germany off from gas supplies in the summer of 2022. We document two key margins of adjustment. First, Germany was able to replace substantial amounts of Russian gas with imports from third countries, underscoring the insurance provided by openness to international trade. Second, the German economy reduced gas consumption by about 20 percent, driven mostly by industry (26 percent) and households (17 percent). The economic costs of demand reduction were manageable with the economy as a whole only experiencing a mild one-quarter contraction in the winter of 2022–2023 and then stagnating. Overall industrial production decoupled from production in energy-intensive sectors (which did see large drops) and declined only slightly. We draw a number of key lessons from this important case study about the insurance offered by access to global markets and the power of substitution, specifically that supply shocks have dramatically smaller costs when elasticities of substitution are very low (but nonzero) compared to a truly zero elasticity.

Rebreather Forum Four consensus statements.

Closed circuit rebreathers have been widely adopted by technical divers as tools for reducing gas consumption and extending depth and duration capabilities. Rebreathers are technologically complex with many failure points, and their use appears associated with a higher accident rate than open circuit scuba. Rebreather Forum Four (RF4) was held in Malta in April 2023 attracting approximately 300 attendees and representatives of multiple manufacturers and training agencies. Over two and a half days a series of lectures was given by influential divers, engineers, researchers and educators on topics of contemporary relevance to rebreather diving safety. Each lecture was followed by a discussion session with audience participation. Potential consensus statements were drafted by the authors (SJM and NWP) during the course of the meeting. These were worded to be confluent with some important messages emerging from the presentations and subsequent discussions. The statements were presented one by one in a half-day plenary session of participants, and discussion was invited on each. After discussion and any necessary revision, the participants voted on whether to adopt the statement as a position of the forum. A clear majority was required for acceptance. Twenty-eight statements embracing thematic areas designated 'safety', 'research', 'operational issues', 'education and training', and 'engineering' were adopted. Those statements are presented along with contextualising narrative where necessary. The statements may help shape research and teaching initiatives, and research and development strategies over subsequent years.

Design of Heat Pipe Air Preheater for 10 t/h Gas-Steam Boiler

This design is aimed at energy -saving and designed a heat pipe air preheat to recover 10T/H steam gas boiler flue heat waste heat, thereby increasing the efficiency of the boiler and reducing gas consumption. This article first introduces the thermal pipe, heat pipe heat exchange, and boiler thermal system, and then focus on the design and optimization of the heat pipe air heater. This design optimizes the thermal pipe specifications of the heat pipe air heater and the parameters of the fins. At the same time, the sealing structure, the fixed structure, and the airport structure are optimized. Subsequently, the UG software created a three -dimensional physical model model and rendering model, and finally proposed corresponding countermeasures on equipment corrosion, thermal pipe life and tube vibration problems. This design uses Excel software to make design calculation tables. Through input parameters, the results of the results of the number of thermal pipes can be obtained.

Industrial gas turbine performance prediction and improvement – a case study

Abstract The gas turbines (GTs), model M3142R/GE MS 3002, equipping the natural gas compression and crude oil pumping stations of SONATRACH’s pipeline transport of hydrocarbons activity are robust despite their dilapidation and state of service, but mediocre in terms of energy efficiency and power output. According to the manufacturer, for temperatures ranging from 15 to 47 °C, the efficiency of these machines drops from 26.78 to 25.03 % and their power drops from 11.29 to 8.9191 MW. It should be noted, however, that the number of these turbines exceeds 80 units and that their operation dates from 1974. The intention of this paper is to improve the gas turbine performance, mainly the efficiency and shaft power, by an evaporative cooling process of the compressor intake air. Besides, it is proposed to lower the upper limit power in periods of high temperatures to reduce gas consumption. To achieve these objectives, a mathematical model was implemented under Matlab R16, which reproduced the real behavior of these machines. It follows that this simulation made it possible to highlight relevant gains in terms of power and efficiency of the order of 1.361 MW and 3.4 % at a temperature of 47 °C.

Towards the concept of gas-to-power demand response

Due to the war in Ukraine, the European Commission has released its “Save Gas for a Safe Winter” plan, communicating the goal of reducing gas consumption in the electricity sector, among others. In this paper, the gas consumption in the electricity sector is picked up and the well-established concept of demand response is brought into alignment with the consumption of gas in the electricity sector, leading to the concept of gas-to-power demand response. Two proposed programs based on this concept are then applied in a production planning approach that shows how companies could proactively contribute to easing the tense situation in Europe, particularly in Germany, especially using methods such as scheduling and/or lot-sizing. This article is intended to serve as a basis for further discussions in the political and economic sectors.

MyEasyHealthcare: An efficient and secure three‐tier blockchain‐based healthcare system

AbstractBlockchain systems have seen vast growth due to the immense potential in developing secure applications for education, healthcare, and so forth. The healthcare system is extensively researched to provide convenience to human life. With the exponential growth in healthcare systems and devices, patient data security and privacy issues are becoming primary concerns. Blockchain is emerging as a solution to secure healthcare records, but it faces certain shortcomings like transaction time, execution time, gas cost consumption, bandwidth utilization, and so forth. The current article designed an extensive blockchain‐based healthcare system (MyEasyHealthcare) with reduced gas consumption, transaction cost, execution cost, and bandwidth utilization, along with enhanced security at three levels. At the first level, the professionals and patients get registered, which provides identity access management. Secondly, authorization is required for each registered entity by the owners. Lastly, the third level includes a doctor‐patient relationship where the hospital's owner assigns a patient to a particular doctor. The data is protected from the outer world and is preserved only between the doctor and the patient. Moreover, to include the majority of tasks for hospital management, the developed system incorporates a smart contract to record seven different parameters for patient diagnosis by a physician and 15 different parameters by a pathologist. The designed system is evaluated for the amount of gas consumed, transaction cost, execution cost, and bandwidth utilization by simulating/executing the written smart contract on InterPlanetary File System (IPFS) and Remix to check the feasibility of the developed system (MyEasyHealthcare) for the real world; the results testify the proposed system is useful in the real world.

Structural Design of Aerostatic Bearing Based on Multi-Objective Particle Swarm Optimization Algorithm

Aerostatic bearings are considered crucial components that can improve the measurement accuracy of ground simulation tests of space equipment. A structural optimization design method is proposed to enhance the static performance of aerostatic bearings. A mathematical model which can quickly calculate the aerostatic bearing capacity and gas consumption is established, and the influence of structural parameters on bearing performance is analyzed using simulation software. By comparing the convergence time and convergence results of the algorithm using different initialization methods, the Latin hypercube initialization method is selected instead of the random initialization method. The multi-objective particle swarm optimization algorithm is used to obtain the optimal solution set distributed in the objective space. It is found that the optimized structural parameters meet the requirements of improving the capacity and reducing gas consumption, which verifies the method’s effectiveness in designing the structural parameters of aerostatic bearings.

Replacing gas boilers with heat pumps is the fastest way to cut German gas consumption

The supply security of fossil gas has been disrupted by the Russo-Ukrainian War. Decisions to relocate the production and transport of gas have become so urgent that new long-term contracts are imminent that undermine the Paris Climate Agreement. Here, we simulate how quickly the addition of renewable electricity and the installation of heat pumps can substitute enough gas to reduce supply risk, while taking a decisive step towards meeting the Paris Agreement. Our bottom-up modelling, using Germany as an example, shows technical pathways on how installing heat pumps is one of the fastest ways to reduce gas consumption, in addition to reducing the load hours of gas-fired power plants. With targeted efforts, maximally 60% of gas from the Russian Federation can be substituted by 2025 with heat pumps and grid expansions, and enough electricity will remain available that the phase-out of coal and the entry into e-mobility will still be practicable.

Changes in the energy supply strategy of the EU countries amid the full-scale Russian invasion

Russia’s full-scale invasion of Ukraine could have a profound impact on short-term solutions to the energy crisis (due to the loss of long-term contracts for additional volumes of Russian gas). It could block a unified agenda because of diverging interests of European countries, reduce European negotiating power, and therefore, weaken Europe’s resistance to Russian energy coercion in the long term. The article confirms the hypothesis that the European energy crisis leads to a slowdown in production and is caused primarily by smaller gas reserves, higher prices and tighter global supplies. Based on the study of a specially developed index and the results of assessing the state of energy independence of the European Union since the beginning of the 21st century made it possible to carry out the task of researching changes in the energy supply system of the EU countries against a background of the Russian war. The demonstration of a map of the most relevant ways of importing pipelines to the EU indicates the need to change the directions of diversification of the energy imports structure. The goal-setting of the directions of implementing the «Fit For 55» programme regarding the reduction of gas consumption by 2030 was studied and the strategy of reducing the dependence of the European Union on Russian gas was analysed.

Перестройка газового рынка Европы: интересы стран-импортеров и компаний-экспортеров

The article focuses on the process of restructuring the natural gas market in Europe. It is shown that the transformation of the European gas market is taking place under the decisive influence of the political decision of the European Commission and the governments of the EU largest gas consuming countries, first, to reduce gas consumption as much as possible in the shortest time; second, to replace Russian gas with imports from alternative sources. As both tasks have the highest priority, the EU countries act within the framework of political, not market logic, regardless of significant economic costs. To hedge against very high gas prices EU introduced since 15 February 2023 the market correction mechanism, capping the price of gas from the above. It is also expected the mandatory filling of gas storage facilities to at least 90% of their capacity before the winter season since 2023 would pressure gas prices downwards. Natural gas exporting companies operate within a system of market coordinates and are ready to participate in the process of transforming the European natural gas market only to the extent that does not contradict their economic interests. The politicization of gas cooperation between the EU and the US at the interstate level cannot change the market behavior of companies. Given the uncertainty regarding the perspective demand for gas in Europe, gas exporting companies are interested in concluding long-term contracts for the export-import of gas on a “take or pay” basis. Europe’s unwillingness to massively engage into the long-term import-export contracts for LNG and readiness to bear additional costs in the form of elevated gas prices will allow companies in the short-term period to make high profits on the spot market.