Energy Conservation Requirements Research Articles

Development of solid waste-based self-insulating material with high strength and low thermal conductivity

Foam concrete as a thermal insulation material has been widely used to meet building energy conservation requirements. In this study, a low-clinker foamed concrete was prepared with an amount of solid waste, including fly ash, carbide slag, and glauber's salt, up to 80%. The effect of polycarboxylate superplasticizers (PCs) in the preparation process was examined to improve the mechanical properties of this particular system. The characteristic of hydration products and the pore structure was analyzed to illuminate the PCs influence on the hydration process. The outcomes demonstrate that the PCs can effectively improve the slurry's fluidity, enhance its compressive strength, and decrease its average diameter. Low-clinker foamed concrete's compressive strength reached 5.3 MPa, and its thermal conductivity reached 0.1556 W/(m·K). It was concluded that foam concrete has the potential to be widely used in green buildings due to its high strength and low thermal conductivity.

Identifying safety issues from energy conservation requirements

AbstractIn cyber‐physical systems such as robots and automated vehicles that rely heavily on batteries, safety, and energy conservation can result conflicting requirements when not considered together. In systems engineering, the development begins at a concept phase where we have high‐level information of different components of the system. During the concept phase, we perform hazard analysis and risk assessment, define safety goals, and derive safety requirements. This means requirement engineering occurs at the end of the concept phase. However, energy conservation recommendations are not taken into consideration until the detailed design with specific hardware and software is known. Hence, it is possible to recommend energy conservation behaviors that can compromise system's safety. If we perform a trade‐off analysis between safety and energy conservation at a concept phase, we can propose various design alternatives and choose the best one that offers a safe and energy saving architecture. To achieve this goal, we propose an approach for identifying safety issues that can be caused by energy conservation recommendations. To evaluate the effectiveness of our approach, we performed an empirical study on four robotic systems. Our results show that we can find energy conservation recommendations that can compromise safety at a concept phase.

Combined cooling, heating, power and oxygen for hospital buildings employing photovoltaic power and liquefied methane

To enhance the energy and gas supply security and reduce the greenhouse gas emission simultaneously, this paper presents a new cryogen-based co-production concept of combined cooling, heating, power and oxygen (CCHPO) for hospital buildings. By integrating with local photovoltaic power generation, two cryogenic liquids of liquefied methane and liquefied oxygen are used to store and produce multiple energies and medical gas. Detailed system modeling and performance analysis are carried out regarding the actual energy and gas consumption data from hospital buildings. The results obtained show the proposed CCHPO solution can be expected to fulfill the simultaneous requirements of energy conservation during normal operation and sustainable energy and gas supply during emergency operations.

Multiobjective optimization of multisource heating system based on improving diversification and implementation

The multiobjective optimization of the system usually focuses on the optimization of the objective functions while ignoring the influence of decision variables on the implementation of the solution. This paper proposes a new improved optimization method by embedding the decision variable diversification mechanism in the optimization process, adopting the discretization mechanism in the multisource complementary heating model, and improving the search space. The new improved optimization method and the original method have similar performance in obtaining the Pareto front, and the hypervolume of the two algorithms differs by only 1.37% on average. The standard deviations of the decision variables in the optimal solutions obtained by the improved algorithm are increased by 70%, and it has a higher diversity of solutions in the decision space. The equipment capacity obtained by the improved algorithm is discretized, and avoids equipment with lower capacity which is beneficial to construction. In this paper, the optimal implementation solution is obtained through the selection of the objective functions by the overall planners and the construction preference of the solution implementers. In this way, the overall planners' requirements for energy conservation, emission reduction and economy, as well as the solution implementers' choice of implementation solutions can be comprehensively considered. In addition, this paper also obtains another optimal solution for adopting the carbon pricing method.

Spatial-temporalcharacteristics and regional differences of the freight transport industry's carbon emission efficiency in China.

The freight transport industry is an important field in which to achieve the goal of carbon emission reduction within the transportation industry. Analyzing the spatial–temporal characteristics and regional differences in the freight transport industry’s carbon emissions efficiency (CEE) is an essential prerequisite for developing a reasonable regional carbon abatement policy. However, few studies have conducted an in-depth analysis of the freight transport industry’s CEE from the perspective of geographic space. This study combines the super-efficiency slack-based measure (SBM) model and the window analysis model to measure the freight transport industry’s CEE in 31 Chinese provinces from 2008 to 2019. We then introduced a spatial autocorrelation analysis and the Theil index to analyze the spatial–temporal evolution characteristics and regional differences in the freight transport industry’s CEE in China. The results show that (1) the overall level of the freight transport industry’s CEE is low, with an average of 0.534, which showed a weak downward trend during the study period. This indicates that the freight industry’s CEE has not improved, and there is a massive requirement for energy conservation and emission reduction. (2) From 2008 to 2019, CEE gradually shows a spatial distribution pattern of being “low in the west and high in the east,” with a significant, positive spatial correlation (all passed the significance level test at P < 0.01). This indicates that the spatial diffusion and inhibition of the freight transport industry’s CEE in adjacent areas cannot be ignored. (3) The overall differences in the freight transport industry’s CEE show a fluctuating upward trend from 2008 to 2019. The inter-regional differences of the three regions (east, central, and west) are the main contributors of the total differences. Therefore, narrowing inter-regional gaps in CEE is one of the main ways to improve the freight transport industry’s CEE.

Influence mechanism of flow parameters on temperature field in the regenerative reheating furnace

Aimed to the complex characteristics of regenerative pusher reheating furnace, the time-domain coupling relationship of burner layout, injection angle, air-gas ratio was simulated to analyze the influence of flow field on the transient temperature field and the smoke emission. Firstly, according to actual flow rules under different section conditions, the equivalent heat transfer of convection and radiation was the key for establishing the combustion model. Secondly, more details of complex flow fields were provided by the finite element method, which explained the dynamic heat transfer effect on at different atmospheres of furnace by the burner angle, the preheating temperature and the air-gas ratio. Industrial cases testified that new method obviously improved the stability of furnace temperature and pressure. When the average gas flow was reduced by 5.4% and the average furnace pressure was reduced by 12.5%, the average temperature difference was able to control within ±1 °C. Remarkably, the better flow field improved the prediction accuracy of temperature field, which could avoid some problems such as the insufficient burning, the over burning, the overheating and so on. Moreover, it also significantly reduced the gas consumption, the pollutant emission and the oxidative loss. Thus, new method aimed to meet strict index requirements of energy conservation and environmental protection to a large extent.

Performance investigation and evaluation of a new three-piston pump energy recovery device for small scale desalination system

Energy recovery device is a crucial part for decreasing the energy consumption of membrane desalination system. To meet the energy conservation requirements in small scale desalination system, a new three-piston pump energy recovery device integrating the high pressure pump and booster pump is investigated and evaluated. The flow characteristics in pressure exchanging cylinders are investigated through the numerical method. The operating performance is experimentally evaluated in a membrane desalination system at the seawater pressure and flowrate of 5.00 MPa and 6.10 m3/h. The numerical results indicate that the continuous flow and pressure transition can be realized through the cooperation of three hydraulic pistons in operation. Both the inlet and outlet flowrates demonstrate the half-sine variation trends. The maximum deviation between simulation and experiment is 2.70%. The experimental results prove that the device can achieve the stable pressure exchanging, and the pressure and flowrate fluctuation amplitudes are 0.60 MPa and 0.60 m3/h. The energy recovery efficiency is as high as 82.03% which contributes to a specific energy consumption of 3.62 kW·h/m3 in desalination. This paper provides a new type of multi-functional energy recovery device for the membrane desalination system.

Energy Conservation Measures and Value Engineering for Small Microgrid: New Hospital as a Case Study

Energy conservation measures can not only improve energy efficiency; it can also enhance microgrid resilience. This paper aims at investigating energy conservation in a small microgrid, using a new hospital in Riyadh city as a case study, to satisfy the Saudi Building Code (SBC part 601) requirement of energy conservation as the first case. The second case study aims to apply and simulate additional advanced energy conservation requirements. The new hospital has considered energy conservation measures uch as upgraded Heating, Ventilation, and Air Conditioning (HVAC), lighting type effect, thermal insulation, and window material. These energy conservation considerations made a difference in the annual energy saving and efficiency of its microgrid. This study used Autodesk Revit software to obtain building information modeling (BIM) and eQUEST to perform energy simulations. The two software programs are integrated together to perform comprehensive energy simulations with detailed building information from the model by Autodesk Green Building Studio (GBS). The energy conservation measures mainly focused on energy management and saving in the building’s electrical installations. All utilized equipment in the hospital should follow the Saudi standards issued by the national authorities. The simulation results revealed a noticeable annual energy saving of up to 19.82% for the second case, using a great thermal resistance building envelope, energy-saving lighting system, and highly rated Energy Efficiency Ratio (EER) HVAC system compared to the first case. More than 100,000 SR in yearly energy saving was achieved by implementing the second case study. Applying the Value Methodology (VM) to the proposed hospital in this study saved more than 700,000 SR in the initial cost of the hospital.

Dynamic coupled heat transfer and energy conservation performance of multilayer glazing window filled with phase change material in summer day

Windows as indispensable for buildings play an important role in decreasing building energy consumption and improving indoor thermal comfort. However, the conventional windows made of the pure glazing units fail to meet the requirements of energy conservation for buildings due to poor thermal insulation. Recent researches found that the application of phase change materials (PCM) can improve the heat transfer performance of glazing unit and the PCM-filled glazing units have advantage in reducing building energy consumption and improving indoor thermal comfort. Therefore, the dynamic coupled heat transfer and energy conservation performance of PCM-filled multilayer glazing unit are investigated numerically in this work. A transient coupled heat transfer model considering conduction, phase change and solar radiation transfer in glazing unit is established, and the energy conservation performance is analyzed based on the heat transfer calculation. Results show that the PCM-filled multilayer glazing unit can significantly reduce energy consumption compared with pure glazing unit, and the energy saving rates are 14.55% for double glazing unit, 33.89% for triple glazing unit and 50.71% for four glazing unit, respectively. In addition, the effects of optical and thermal parameters of PCM on thermal performance of glazing units are investigated thoroughly. It is found that the PCM-filled multilayer glazing unit has advantages in thermal insulation which is good choice for transparent envelope in the building fields.

Mild hydrogenation pretreatment of FCC slurry oil for high-value-added utilization: Exploitable high-boiling components and carbonization discrepancy

In response to the enormous market demand for high-value-added carbonaceous materials and the urgent requirement of energy conservation and emission reduction, FCC slurry oil (SO) has drawn widespread attention in the preparation of these kinds of carbonaceous materials due to its abundant aromatic hydrocarbon contents. Distillation can be utilized as a pretreatment to efficiently remove the quinoline insoluble and other undesirable components in SO before carbonization. However, the distillate depth and yield are greatly restricted by the conspicuous coking phenomenon during thermal effect in the distillation. Mild hydrogenation coupled with distillation were adopted as the pretreatments before carbonization and effects of the hydrogenation on the distillation process were studied. Besides, transform patterns for the properties of sub-fractions in specimen before and after hydrogenation and resulted variations in carbonization performances were then systematically analyzed. Through hydrogenation, the distillation depth of hydrotreated SO (HSO) could be greatly improved to 530 °C with no significant coking phenomenon and the distillation yield was increased dramatically (from 38.4 wt% to 68.1 wt%). Especially, partial super high-boiling (above 530 °C) components in SO could be transformed into naphthenoaromatic structures by hydrogenation and acquired through distillation for further utilizations. Using anthracene as chemical probe, the hydrogen-donating abilities (HDAs) of specimens were detected, and results indicated the amounts of transferable hydrogen in HSO low-boiling and high-boiling sub-fractions were greatly increased compared with that of SO, which would provide the specimen with stronger stability in the thermal treatment and restrain the rapid coking. The carbonization performance varied with the properties of sub-fractions and a section of high-boiling components in SO was discovered to be exploitable through hydrogenation and demonstrated to be beneficial in the preparation of needle coke.

Numerical simulation of particle screening efficiency of large multi-layer vibrating screen based on discrete element method

With the increasing requirements for energy conservation and environmental protection, multi-layer vibrating screens have become hot issues. Compared with single-layer vibrating screens, multi-layer vibrating screens has much better performance in terms of processing effect, treatment capacity, and environmental protection. The research on the physical parameters of the multi-layer vibrating screen is of great significance to the actual production. However, analysis and simulation studies of multi-layer vibrating screens are limited. In this paper, the screening process of wet particles on a multi-layer vibrating screen was simulated by using the discrete element method. The characteristics and application scope of the two vibration modes were analyzed. The particle penetration rate, the number of collisions, and the distribution of the particles under 23 combinations of structures and vibration parameters were investigated. The influence of different parameters on screening performance was analyzed. Several optimal combinations of frequency, amplitude and screen inclination angle under different working conditions were obtained. The screening efficiency of the balanced elliptic motion is higher than that of the linear motion. The best combination of the three parameters is 4 mm amplitude, 20 Hz frequency, and 3° inclination angle. The efficiency is higher when the particles follow a distribution of arithmetic on the screen. This study provides a reference for the efficient operation and optimal design of large multi-layer screening equipment.

Research on Model Predictive Control Strategy of Converter in Building DC Power Supply System

The popularization of distributed renewable energy, the change of end-user load charACteristics, and the requirements of energy conservation and environmental protection have brought great challenges to the traditional AC power supply. Compared with AC power supply, DC power supply is widely concerned because of its powerful energy-saving advantages. Building electricity demand fluctuates greatly, and various power loads are frequently switched, which requires a higher demanding for the dynamic response capability. Based on switched system theory, this paper proposes a switched control method for building dc microgrid converter. The outer voltage loop adopts PI control and the inner current loop adopts predictive current control. The switched control model of the converter is established and the optimal switched rate is designed. An experimental platform based on SiC MOSFET is built for verification. The switched frequency is 50KHz, which verifies the effectiveness of the control strategy.

Hierarchical Optimization Decision-Making Method to Comply with China’s Fuel Consumption and New Energy Vehicle Credit Regulations

The national targets of reaching carbon peak in 2030 and carbon neutrality in 2060 propose higher requirements for energy conservation and emission reduction of China’s automobile industry. As an important measure for the government, the fuel consumption and new energy vehicle (NEV) credit policy system has a significant impact on the Chinese and even the global vehicle market. Considering the lack of a systematic evaluation model for China’s fuel consumption and NEV credit regulations, this study establishes a hierarchical optimization decision-making model based on technology frontier curves and a multi-dimension database containing extensive data of technologies, products, and enterprises in the Chinese market to simulate and evaluate the technology compliance and policy impact under multiple regulations. The results show that, from the perspective of the technology frontier curve, gasoline technologies still have great cost-effectiveness advantages when the fuel-saving requirement is less than 46%, and the space for plug-in hybrid electric vehicles (PHEVs) and range-extended electric vehicles (REVs) is gradually shrinking due to the cost reduction of battery electric vehicles (BEVs). BEV400 will be better than PHEV70 and REV100 when the fuel-saving requirement is higher than 79%. Diesel vehicles are always not competitive in the passenger car market. In terms of the compliance of corporate average fuel consumption (CAFC) regulation, the start-stop technology will be gradually phased out and mild hybrid electric vehicles will be rapidly introduced due to their high cost-effectiveness in 2025. With the tightening of regulations, the penetration rate of BEVs and PHEVs will be 23.7% and 6.7%, respectively, and mild hybrid electric vehicles will be gradually replaced by strong hybrid electric vehicles in 2030. By 2035, the penetration rate of BEVs and PHEVs will be 43.6% and 6% further. For the CAFC and NEV credit regulation (widely known as the dual credit regulation), the single-vehicle credit poses a greater impact on the penetration of NEVs than corporate credit percentage limitation and is the key factor that should be focused on. The NEV credit limitation in the dual credit regulation could push ‘poor performance’ automakers to produce the required number of NEVs and meet the bottom line. However, in the long term, when compared to the CAFC regulation, the dual credit regulation is more lenient, due to NEVs being able to get double benefits both on NEV credit and CAFC credit, and NEV credit can also unidirectionally compensate CAFC credit under the dual-credit policy context. With the increased penetration and cost reduction of NEVs, the ‘averaging’ effect of dual credit regulation will inhibit the development of energy-saving and new energy vehicles. Therefore, eliminating the connection between NEV credit and CAFC credit or only leaving the CAFC and the fuel consumption limit regulations in the future will be better for the long-term development of the energy-saving and new energy vehicle industry.

Research on preparation of low bulk density Claus tail gas hydrogenation catalyst

With the continuous improvement of national energy conservation and emission reduction requirements, oil and natural gas production industry has increasingly strict requirements for SO2 emission from tail gas. Nowadays, most of large and medium-sized natural gas purification plants and refineries adopt hydrogenation reduction tail gas treatment process to achieve ultra-low SO2 emission, which puts forward high requirements for the activity, stability and economy of tail gas hydrogenation catalyst. In recent years, due to the high price of hydrogenation catalyst, it has become a research hot spot to reduce the cost of catalyst by reducing the bulk density. Traditional catalyst preparation process focused on the types and properties of support and active components, while the influence of alumina powder properties and preparation conditions have not been paid enough attention. With the extensive application of fine characterization methods and the further understanding of catalyst micro-structure, the influence of alumina powder properties and preparation conditions on the performance of catalyst are more and more obvious. In this paper, the Pseudo boehmite was investigated. TG, SEM, XRD and other characterization methods were used to study the preparation method of low bulk density Claus tail gas hydrogenation catalyst.

Spectra of Acoustic-Gravity Waves in the Atmosphere with a Quasi-Isothermal Upper Layer

In this paper, we study, in theoretical terms, the structure of the spectrum of acoustic-gravity waves (AGWs) in the nonisothermal atmosphere having asymptotically constant temperature at high altitudes. A mathematical problem of wave propagation from arbitrary initial perturbations in the half-infinite nonisothermal atmosphere is formulated and analyzed for a system of linearized hydrodynamic equations for small-amplitude waves. Besides initial and lower boundary conditions at the ground, wave energy conservation requirements are applied. In this paper, we show that this mathematical problem belongs to the class of wave problems having self-adjoint evolution operators, which ensures the correctness and existence of solutions for a wide range of atmospheric temperature stratifications. A general solution of the problem can be built in the form of basic eigenfunction expansions of the evolution operator. The paper shows that wave frequencies considered as eigenvalues of the self-adjoint evolution operator are real and form two global branches corresponding to high- and low-frequency AGW modes. These two branches are separated since the Brunt–Vaisala frequency is smaller than the acoustic cutoff frequency at the upper boundary of the model. Wave modes belonging to the low-frequency global spectral branch have properties of internal gravity waves (IGWs) at all altitudes. Wave modes of the high-frequency spectral branch at different altitudes may have properties of IGWs or acoustic waves depending on local stratification. The results of simulations using a high-resolution nonlinear numerical model confirm possible changes of AGW properties at different altitudes in the nonisothermal atmosphere.

Thermodynamic analysis of a novel multi-target-temperature cascade cycle for refrigeration

Cascade refrigeration has been recognized as a prospective technology to meet the requirement of cryogenic refrigeration and energy conservation. To fulfill the demand of the multi refrigeration temperatures and overcome the existing problem in the commercial and industrial applications, a novel multi-target-temperature cascade (MTTC) system is put forward, which uses natural refrigerants R717 in the high temperature circuit and R744 and R1270 severally in the low temperature circuits. The optimum performance of the designed cascade refrigeration system is evaluated in terms of economics and thermodynamics and compared with other existing multi-temperature cascade systems. Results show that, MTTC system’s COP is about 25% and 10% higher than that of CSC1 system and CSC2 system; the exergy efficiency of MTTC system is about 19% and 5% higher than that of CSC1 system and CSC2 system; and MTTC system also shows smaller parameter deviation and equivalent system economy compared with the CSC systems. Based on the admirable thermodynamic and thermal-economic performance, MTTC system is believed to have a good practical application prospect.

Energy-Saving and Environmental-Friendly Gymnasium Project Evaluation Research

As a complete urban space individual, the gymnasium must be considered to build energy conservation and environmental protection requirements. Based on this research background, the thesis analyzes whether it can be energy-saving and environmentally friendly by exploring natural ventilation technology and intelligent lighting for green buildings, using CFD and airpark combined with thermal comfort and body temperature. Research has shown that through the CAN bus intelligent lighting system, combined with the opening and closing of the building gymnasium roof to meet the ventilation conditions, the gymnasium’s necessary energy-saving and environmental protection can be realized.

Electrification of rails in China: Its impact on energy conservation and emission reduction

Rail transportation plays a very important role in China’s economic development. China’s train system has experienced the evolution of steam locomotives, diesel locomotives, and electric locomotives, which correspond to the consumption of coal, diesel and electricity respectively. Environmental protection has put forward requirements for energy conservation and emission reduction in rail transportation. The electrification of rails is a general trend of social development. In this process, the fuel consumption of rail transportation is experiencing the substitution of coal and oil by electricity. Therefore, a study on inter-fuel substitution in China’s rail sector is of great significance to the development of China’s rail transport system, energy conservation and emission reduction in rail transportation. We re-derived and revised the formula for inter-fuel substitution elasticity, and made a more reasonable and scientific selection of the ridge regression parameters in the econometric model. The empirical results indicate that in China’s rail sector, the substitution elasticities between coal and oil, coal and electricity, and oil and electricity are about 2.2084, 1.0628, and 0.9202, respectively. We also conducted an inter-fuel substitution scenario analysis and made relevant policy recommendations.

Multi-objective optimization of laminar flow characteristics in helical coiled tubes based on NSGA-II

To meet the requirement of energy conservation and optimize the design of helical coils in laminar flow, the pitch, the coil radius and the average inlet velocity were selected as design parameters to obtain the tendency of the heat transfer and flow resistance characteristics of the helical coils. Heat transfer coefficient and pressure drop per unit length of helical coils were taken as the optimization objective functions. A multi-objective optimization model was established, three candidate points A, B and C were obtained based on Non-dominated Sorted Genetic Algorithm-II (NSGA-II). The results showed that heat transfer coefficient and pressure drop per unit length increase with the pitch and inlet velocity whilst them decrease with coil radius, among which the influence of inlet velocity is the most obvious and the pitch is the least. It was found that the coil radius of most points in Pareto front was relatively concentrated. The comprehensive performance of candidate points A, B, C had been improved significantly by 16.3%, 28.3% and 19.6% respectively.

Research on energy consumption monitoring and control method of energy saving and emission reduction for hybrid ships

Hybrid ship as a kind of transport mode with high energy consumption, the monitoring of energy consumption and the control of energy conservation and emission reduction are particularly important. Therefore, effective energy consumption monitoring and emission control methods in the process of ship operation have attracted great attention in related fields. Therefore, this study optimized the structure of the energy consumption monitoring equipment for hybrid ships, and achieved the energy consumption monitoring and control by effectively collecting the energy consumption data of hybrid ships. The application of real-time monitoring system for ship energy consumption can better monitor the energy consumption of hybrid ships and realize the treatment and control of energy conservation and emission reduction according to the monitoring results. At the same time, according to the current situation of ship energy consumption management, through the analysis of the characteristics of ship operation and diesel engine fuel system, this study proposed a low loss, high precision mass flowmeter, to achieve the requirements of energy conservation and emission reduction control. Based on this, strengthening ship basic management, saving Marine fuel and reducing pollution can achieve a win-win situation between economy and environment.