Relative Energy Efficiency Research Articles

Assessment of Final Space Cooling Consumption in the European Transportation Sector

The current study aims to investigate one of the most underexplored energy fields in scientific research, i.e., final energy consumption (FEC) of space cooling (SC) in the European (EU27+UK) transportation sector with 2019 as a baseline. The fundamentals of this study include a comprehensive literature review as well as the creation of a dataset characterized by completeness and reliability. Different essential input parameters have been investigated and the encountered data and information gaps have been filled. The transportation sector has been broken down into three main categories, namely, light, medium, and heavy vehicles. Throughout the EU27+UK, the number of vehicles, equivalent full load hours (EFLHs), system power capacities, and their related energy efficiency levels have been collected. The collected data and information have been computed and the EU27+UK FEC for space cooling in the transportation sector resulted in more than 125 TWh/year. It is worth underlining that the light vehicles category accounted for the majority of the total FEC, followed by the medium and heavy vehicle categories, respectively.

ENERGY-ECONOMIC ANALYSIS SECTORS OF THE ECONOMY OF UKRAINE

The work is devoted to methods of calculating the total energy intensity of fuel, currency, products, labor costs, raw materials and materials necessary for the practical application of energy-economic analysis of production efficiency. The article proposes a simplified methodology and performs calculations to estimate the total energy intensity of currency and products of seven sectors of the economy of Ukraine, which produce food, mineral, chemical, metallurgical and machine-building products, as well as services - transport and computer programming. Calculations were made for three types of fuel - nuclear fuel, coal and natural gas, which in 2017 accounted for more than 76% of total fuel consumption in Ukraine. The main components of the total energy intensity of the products of the national economy are due to the use of fuel for the production of fuel, electricity and heat and raw materials, as well as the cost of fuel for the production of products that workers buy for wages. The article identifies the relative energy and economic efficiency of fuel use in the economy of Ukraine

Measuring the efficiency of energy planning under uncertainty

This paper proposes an optimization method for energy planning that will efficiently meet multiple requirements subject to uncertain future projections. A stochastic optimization model is used to identify appropriate energy mixes under various scenarios of uncertainty, and the performance of three different energy policies—a pro-economic policy, a pro-environmental policy, and a governmental plan—is compared. Data envelopment analysis is applied to measure the relative energy efficiency of the optimized energy mixes in providing energy security, energy equity, and environmental sustainability. Thailand’s power development plan for 2032 is used as a case study to illustrate the approach. Analysis of the case study indicates that the pro-environmental policy is the most efficient of the three policies considered. Empirical results from this study provide quantitative support for policy makers seeking to establish an efficient energy policy to satisfy the three requirements while allowing for a range of future uncertainties.

Solute selectivity, separation mechanism and application performance of freezing wastewater treatment: Focus on air cooling and direct contact cooling

Freezing separation is a green and high efficient wastewater treatment technology. Considering the problems of freezing methods, treatment specificity and relative energy efficiency, an air cooling device and a direct contact cooling device were developed. The removal rates, ice-forming rates, and energy efficiency of different freezing methods were investigated with different concentrations of inorganic salt ions, small molecule organic matter, and organic polymer solutions. The results showed that there was solute selectivity in freezing separation, while the separation effects increased in decreasing solute concentration, with higher solute removal rates for inorganic salt solutions and small molecule organics and lower removal efficiency for high molecule organics, and there was the highest potential application value of copper contact column by comparing the removal rates and composition ratios. In addition, stirring enhanced the solute removal rate significantly, which affected the concentration gradient distribution and the microenvironment of the ice-forming interface. In the treatment of condensate wastewater from MVR(Mechanical Vapor Recompression) system and dye wastewater with high salt and high organic, the results showed that the removal rates reached 70% and 50% respectively, and it provided reference to the application of freezing separation in practical water treatment.

ENERGY SECURITY AND ENERGY EFFICIENCY PRIORITIES IN THE REPUBLIC OF AZERBAIJAN

Energy security and related energy efficiency issues are part of the national energy strategy in most economically developed countries. In the modern world, energy security also includes issues related not only to the quantity of consumption, but also to its quality. In this regard, a sustainable socially oriented state does not separate energy security from energy efficiency and considers it an important indicator of the country's level of development. The Republic of Azerbaijan is also among the countries of the world with abundant hydrocarbon energy resources in terms of current and future prospects. Although energy security is ensured in the country, its strengthening and enrichment with elements of energy efficiency are the main priorities of the ongoing reforms. This issue is also of scientific relevance. In this regard, the article deals with issues related to energy security and energy efficiency priorities in the Republic of Azerbaijan.

Relative energy efficiency indicators calculated for high-moisture waste-based fuel blends using multiple-criteria decision-making

In this paper, we present a comprehensive evaluation of low-rank fuel compositions obtained using multi-criteria decision-making methods. Here we used a unique combination of parameters, especially important for gaining an insight into the prospects of industrial combustion of water slurries based on waste. The research involved six sets of criteria (cost, energy efficiency, ease of preparation and storage, atomization, fragmentation, and emissions) including a total of seventeen characteristics determined experimentally. An integral efficiency indicator was calculated in each set using the Weighted Sum Model. After that, an overall indicator was calculated accounting for all the key factors. The integral indicator ranged from 0.4 to 0.9 in all the six categories of criteria. The lowest overall efficiency indicators (0.239–0.487) were typical of the fuel containing 50% of flame coal filter cake, 40% of water, and 10% of turbine oil. According to the analysis, the blends based on coal slime and water can be considered the best fuels. The main application of the research findings is the development of compositions to provide positive effects at the stages of fuel preparation, storage, transportation, atomization, and combustion.

Effects of extrusion parameters on physicochemical properties of third generation corn snacks expanded by microwave heating

Corn grits were extruded then extrudates were expanded by microwave-heating. Effects of addition of xanthan gum (XG) (0%–1%), feed moisture content (37%–47%) and screw speed (100–300 rpm) level on physicochemical properties of snacks were evaluated with response surface methodology (RSM). All suspensions of expanded samples exhibited shear-thinning behavior. Apparent amylose content of samples ranged from 22.47% to 37.97%. Screw speed and feed moisture content had positive effect on apparent viscosity and amylose content but XG level had negative effect on them. Increasing screw speed increased expansion and luminosity but decreased browning index and total color difference. Increasing feed moisture content resulted in reduced expansion, luminosity but increased browning index. In contrast to the initial effect, expansion and browning index decreased when XG addition level was above 0.5%. Optimum conditions were determined to obtain the maximum values for expansion index and luminosity and minimum value for the total color difference by desirability function. They were found as 300-rpm screw speed, 47% feed moisture content and 0.34% XG level. Practical applications Extrusion process occupies an important place in the food industry for production of snacks and breakfast cereals. This technology is especially preferred due to its versatility, high productivity, relative low cost energy efficiency for snack production. However, extrusion process conditions (feed moisture, screw speed, and barrel temperature) and additives used in this process have critical importance for snack characteristics. Gum addition provides lubrication during extrusion process. Expansion and color characteristics of product may be change according to gum addition level. Response surface methodology (RSM) can be used as an optimization tool to achieve a better product considering multiple quality characteristics for snacks. A better evaluation of simultaneous interactive effects of process variables on the products can be achieved with RSM technique. Application of RSM in this study may be employed as baseline information for further scale-up of third generation snack production with several additives and under different production conditions.

Evaluating the energy efficiency of wastewater treatment plants in the Yangtze River Delta: Perspectives on regional discrepancies

With priorities to reach a carbon emission peak and integrated development involving ecological demonstration, a systematic evaluation on the energy efficiency and internal discrepancies of wastewater treatment plants in the Yangtze River Delta region is needed. In this study, a slacks-based measure data envelopment analysis model was applied to quantify the relative energy efficiency of 270 regional wastewater treatment plants. Based on the score of relative energy efficiency, the internal discrepancies of the region were identified through a method combining spatial and sensitivity analysis. Although the wastewater treatment plants had met the pollutant limits of discharge standards, the result of data envelopment analysis showed that 253 wastewater treatment plants were inefficient (with efficiency scores less than 1) due to input excess or output shortfall, indicating substantial potential for improving the energy efficiency. Besides, binary logistic regression demonstrated the significant impact from explanatory factors including designed capacity (104 m3/d), loading rate (%), influent ratio of chemical oxygen demand to total nitrogen, and influent concentration (mg/L) of chemical oxygen demand. Moreover, with regards to regional discrepancies, proportion of efficient wastewater treatment plants for Shanghai, Jiangsu, Zhejiang, and Anhui differs significantly. The area surrounding Taihu Lake was recognized as the trough of the Yangtze River Delta region in terms of the relative energy efficiency of wastewater treatment plants. This paper would give a reference for optimization of wastewater treatment plants in the study area and the evaluation framework on internal discrepancies might also be useful for other regions worldwide.

Should energy efficiency subsidies be tied into housing prices?

Heat pumps are a key technology for improving energy efficiency as they can significantly reduce energy costs and emissions. Given the significant role of heat pumps in carbon neutrality pathways, and pressure for related national energy efficiency programs, it is important to examine economic profitability of heat pump investments and their relative environmental and social benefits. This paper aims to answer the following main research question: are areas with lower housing prices and income less likely to invest into energy efficiency? The paper finds that in Finland heat pumps are already very profitable and converting buildings’ heating systems into heat pumps creates major environmental and economic benefits for the residents. The cost of heating and heat pump investment costs does not vary between locations whereas housing prices, rents and income do. Neighborhoods with lower housing prices have less motivation and capability to invest into heat pumps. Urban areas with positive housing price development, higher income and better financing options will likely invest into energy efficiency without subsidies. Potential subsidies should be allocated into areas with lower housing prices, because emissions are evenly distributed, and lower income areas pay relatively more for energy. Energy efficiency subsidies could be tied into housing prices or more specifically into property tax, which is universally collected in most countries. Property tax could be used to guide energy efficiency investments into locations where they would not be carried out otherwise. For areas that do not need subsidies, this paper recommends that awareness should be increased, because the economic and carbon emission reduction potential of energy efficiency measures is still not well understood.

Analysis and determination of a seasonal performance evaluation for air source heat pumps

Performance evaluations of heat pumps play an important role in regulating energy markets and promoting energy conservation technologies. The development of air source heat pumps (ASHP) standards, especially seasonal performance factors including the annual performance factor (APF) method and integrated part-load value (IPLV) method, are reviewed for applications worldwide and in China. Based on the reviews, this study introduces and analyzes the methods of evaluating the seasonal performance of ASHPs by analyzing and proposing principles and key factors of seasonal performance evaluations, including building load models, operational period distributions (bin hours), and ASHP performance models. Then, The similarities and differences between the APF and IPLV approaches were analyzed and compared, indicating that the APF method should be applied as a seasonal performance evaluation method for ASHPs (for both air–water and air–air heat pumps). Therefore, the rules for three key factors of seasonal performance evaluations were determined, which take China as an example. The specific results and parameters were calculated according to meteorological data and simulation. Besides, the related energy efficiency limitations and comparisons of the APF index, which greatly improve the ASHP industry, were discussed. This paper provides a basic reference for other countries to formulate their own ASHP standards.

The feasibility of heavy battery electric trucks

Summary Research on the decarbonization of transport often concludes that heavy battery electric trucks are infeasible due to the incompatibility of long driving distance with high energy use and low specific energy and high costs of batteries. However, emphasis is often placed on battery electric range matching that of diesel trucks, instead of overall competitiveness. We model battery electric trucks that use high-power fast charging, enabling smaller batteries and showing that the economics of battery electric trucks per ton-kilometer improves with greater weight, driven by increasing load capacity as well as increased energy savings as a function of weight. Furthermore, we show that previous findings that the competitiveness per kilometer is worse for heavy trucks than for lighter trucks are very sensitive to assumptions about the battery cost per kWh and lifetime of the battery pack. Given the rapid development of batteries, we conclude that the economic feasibility of heavy battery electric trucks might have been generally underestimated.

Evaluation of Energy Efficiency in Thermally Improved Residential Buildings, with a Weather Controlled Central Heating System. A Case Study in Poland

Optimization of energy consumption and related energy efficiency can be realized in various ways, both through measures to reduce heat losses through building partitions and the introduction of modern systems of regulation and management of heat distribution. In order to achieve the best possible results, these actions should be interlinked, especially in older buildings that have undergone thermomodernization. Therefore, the aim of the study was to evaluate actions aimed at improving energy efficiency of buildings made in prefabricated technology. These buildings were thermomodernized and then the weather-controlled central heating system was installed. The study assessed whether the application of the change of the method of central heating regulation from the traditional one, taking into account only the change of external temperature to the weather-controlled one, will contribute to the increase of energy efficiency of buildings. The research was carried out in the existing residential buildings, for which data on the actual energy consumption was collected and elaborated and includes periods before modernization, after thermomodernization and the period after the introduction of the central heating system with weather control. The collected data cover an eighteen-year period of buildings’ use. The obtained results indicate that in Polish conditions the introduction of weather-controlled regulation system in buildings made in prefabricated technology (made of large slab) allows to achieve energy savings in the range of 16–23%, it may be related to their high thermal capacity resulting from the use of concrete elements in the building envelope.

Studying the effect of different operation parameters on the grinding energy efficiency in laboratory stirred mill

In this study, considering different operational parameters for stirred media mill, change in specific energy was compared to the change in Rx values, i.e. the cumulative weight of the material undersized to a specific sieve. R values, namely R38, R75, R106, were measured before and after grinding in stirred mill. The change in Rx (ΔRx, %) values were calculated and they were used to evaluate the certain unit of effectual energy (Ecb). This abovementioned calculation is performed by proportioning the Specific Energy (SE) to ΔRx values. The effectual part of SE is considered to be the ratio of the energy needed only for size reduction in grinding and it should be related to the ΔRx. The relative Ecb ratios of different grinding conditions give the relative specific energy efficiency ratio (SEe). The relative specific energy efficiency ratio is inversely proportional to specific grinding parameters and ground product particle sizes. The relative specific energy efficiency can be considered as the relative amount of energy for various grinding conditions. The variation between relative energy amount and the previously specified particle size provides a realistic comparison of different grinding parameters. The abovementioned variation could be employed to understand the resistance particle size which is a new concept to describe the particle size at which the maximum effectual SE is directly used. In the context of this study, it was aimed to figure out the interrelation between specific energy efficiency and PSD variation along with the resistance particle size.

Mechanism and efficacy of virus inactivation by a microplasma UV lamp generating monochromatic UV irradiation at 222 nm

This study evaluated the potential of a microplasma UV lamp as an alternative UV source to the current mercury-based (Hg-based) UV lamp for water disinfection. We developed a set of PCR-based molecular assays (long-range qPCR, DNase, and binding assay) to quantify the adenovirus genome, capsid, and fiber damage with a wide detection range (100.5-106.5 PFU/mL). We used these molecular assays to characterize adenovirus (AdV) inactivation kinetics by microplasma UV that produced monochromatic UV at 222 nm. We found that the inactivation rate constant (0.142 cm2/mJ) due to microplasma UV was 4.4 times higher than that of low-pressure Hg UV (0.032 cm2/mJ). This high efficacy was attributed to monochromatic UV wavelength at 222 nm damaging the AdV capsid protein. The results of these molecular assays also proved that microplasma UV and medium-pressure Hg UV with a bandpass filter at 223 nm (MPUV223nm) have a similar influence on AdV (p>0.05). We then estimated the relative energy efficiency of MPUV and microplasma UV to LPUV for 4 log reduction of the viruses. We found that the microplasma UV resulted in higher inactivation rate constants for viruses than the current Hg-based UV. Consequently, microplasma UV could be more energy efficient than low-pressure Hg UV for water disinfection if the wall-plug efficiency of the microplasma UV lamp improved to 8.4% (currently 1.5%). Therefore, the microplasma UV lamp is a promising option for water disinfection.

Massive MIMO perspective: improved sea lion for optimal antenna selection

The massive MIMO is an advanced technology in the wideband wireless communication system’s future, which provokes extensive attention in both academia and telecommunication industry. Pilot contamination is considered as a fundamental issue in the system of massive MIMO. The designing of wireless systems has the main concern over the system throughput. Though, the environmental protection and energy-saving have concerned as inevitable trends and global demands. Hence, on considering all these consequences, this paper intends to introduce a new improved sea lion optimization algorithm to select the optimal transmit antennas selection by accounting the multi-objective issue that maximizes both the relative energy efficiency and capacity. In fact, the proposed algorithm is the enhanced version of traditional sea lion optimization algorithm, which optimally tunes the count of transmit antennas and determines which antenna to be selected. Finally, the performance of proposed work is compared and proved over other conventional models regarding capacity analysis, relative efficiency analysis, and optimal antenna selection analysis as well.

An analysis of energy efficiency in multicampi higher education institutions and a novel environmental labeling proposal

The expansion of Brazilian higher education institutions (HEIs) organized in multicampi structures brought a significant complexity to the academic and administrative management. In this context, environmental management strategies become quite relevant, especially when considering the low effectiveness of the Brazilian Labeling Program (BLP) for the classification of buildings in practice. The main objective of the present paper is to evaluate the BLP efficacy as applied to HEI buildings, aiming to develop a new environmental labeling model for multicampi HEIs. For this purpose, the BLP was applied to the labeling of Instituto Federal de Educação, Ciência e Tecnologia do Piauí (IFPI), employing data obtained from electricity bills between 2016 and 2018. The energy diagnosis was performed considering distinct indicators,performance indexes, levels and rankings of relative energy efficiency, from which energy efficiency labels could be developed. The results allow the verification of the low efficiency of the BLP, especially in the environmental labeling of HEIs. From the detailed analysis of bills, it is possible to develop environmental labels inspired by the BLP, resulting in a different approach. A novel type-II environmental labeling methodology is then introduced based on the breakdown of electricity bills and statistical methods.

Substantiating the criteria of choosing project solutions for climate control systems based on renewable energy sources

The choice of project solutions for systems of providing climatic conditions in premises, based on different types of renewable energy sources, was substantiated. The means proposed to solve project tasks, imply the use of the interaction between different stakeholders, the number of subsystems necessary for effective functioning in the open system, that is taking into account the synergetic effect. It was proved that the introduction of complex climate control and energy supply system will allow uniting the functions inherent to disparate engineering systems, and ensure the transformation and redistribution of various types of energy flows, which will minimize operating costs. The hierarchical structure of the problem of approval of alternative project solutions of the climatic systems based on the Analytic Hierarchy Process method was constructed, which allows obtaining a set of optimal variants. The application of the corresponding tool apparatus of Data Envelopment Analysis enables constructing a system of evaluation of the energy efficiency of projects of complex climatic control and power supply systems using different types of renewable energy sources. The functional intended to select the optimum variant of a project solution of the climate control and energy supply system was constructed. The proposed project solutions were examined from the position of determining the minimization of the total consumption of energy resources and operating costs of three alpha-stakeholders. The proposed indicator of relative integrated energy efficiency allows making an optimum choice of complex systems with disparate input and output characteristics

Separating Hydrocarbon Mixtures by Driving the Components in Opposite Directions: High Degree of Separation Factor and Energy Efficiency.

A radically different approach for separation of molecular mixtures is proposed. A judicious combination of levitation effect observed in zeolites with a counter intuitive Landauer blow torch effect provides driving forces for the two components of the mixture to move in opposite directions. Using nonequilibrium MonteCarlo simulations, we illustrate the efficacy of the method for separating real mixtures of both linear n-pentane and its branched isomer, neopentane, and linear n-hexane and its branched isomer, 2,2-dimethylbutane. The method yields several orders of magnitude improvement in separation factor and relative energy efficiency by using submicron zeolite column. The extremely high purity of the resulting single components makes the method best suited for green chemistry.

A Framework for Self-Enforced Interaction Between Connected Vehicles: Intersection Negotiation

This paper proposes an algorithm for resolution of traffic conflicts occurring on an intersection, intended for Connected Autonomous Vehicle (CAV). The algorithm is based on the trade-off between energy consumption and user-defined value of time. The consequent cooperation opportunities originating from agent heterogeneity are captured by a game-theoretic cooperative-competitive solution approach to develop a computationally feasible, self-enforced, cooperative intersection de-conflicting algorithm. It is intended as a component of a robust framework for strategic control of the vehicle’s powertrain. Monte Carlo simulation is used to showcase the decision-making algorithm’s behaviour, to estimate its efficiency as a function of traffic heterogeneity. The results confirm that the proposed algorithm may offer threefold improvement in energy and time efficiency in relation to a First Come First Served scheme.

Spatial differences in energy performance among four municipalities of China: From both the aggregate and final demand perspectives

City, which consumes the majority of the total energy consumptions, has great influences on the national energy issues. As the widespread spatial differences, a quantitative energy analysis among multi-city allows exploring the targeted and distinguishing energy policy implications at the city level in China. Considering the significant role of final demands, the input-output model and spatial structural decomposition analysis were adopted to evaluate the energy performances and quantify the spatial differences. In 2012, the spatial differences in the energy consumptions were distinct, with the greatest gap between Shanghai and Chongqing, which were mainly driven by the domestic Leontief structure effect and the total final demand effect. In particular, the spatial differences in the embodied energy by net domestic outflow were remarkable. For the relative energy efficiency, Beijing was discovered the best, followed by Tianjin, Shanghai and Chongqing. The spatial differences in their energy intensity were primarily influenced by the energy intensity effect and the domestic Leontief structure effect. In addition, the spatial differences in the aggregate embodied energy intensity by domestic investment were prominent. Inspired by the results, the structure adjustments with respect to the production and final demands and regional cooperation are strongly advised at the city level.