Energy Efficiency Grades Research Articles

Recent development of grain oriented electrical steel in Shougang steel

Shougang Steel has been pursuing the development of low iron loss and high permeability grain oriented electrical steels for more than a decade. Grain oriented electrical steel requires a very strong Goss {110}〈001〉 texture and as such a comprehensive control of thermo-mechanical processing parameters is required to achieve a strict control of texture. In this paper the key metallurgical problems associated with manufacture of grain oriented electrical steel are discussed, including the factors that affect both primary recrystallization and secondary recrystallization leading to the development of a strongly textured final sheet. The metallurgical factors affecting magnetostriction of electrical steels are also analyzed, and a technological approach for domain refinement, and its effect on magnetic properties, is described. Examples of magnetic properties under non-sinusoidal magnetization conditions are also reported and analyzed. As a result of continuous research and development efforts the high permeability low iron loss grain oriented electrical steel of thin gauge products of 0.2 mm/0.18 mm thickness have recently been developed to meet the requirements of the new China national standard of energy efficiency grades for power transformers.

A dataset on energy efficiency grade of white goods in mainland China at regional and household levels

To improve energy-saving management, the energy efficiency grade (EEG) was introduced by the Chinese government in the 2000s and mainly implemented for white goods (WGs) in early stages. However, due to the lack of actual statistics, how effective the promotion of high EEG WGs has been in China is still not clear. The China Energy Efficiency Grade (CEEG) of WGs dataset described here comprises (i) EEG-related data on 5 kinds of WGs at the regional (national, provincial) and household levels in China and (ii) predictions of future average EEG trends. By web crawling, retrieving and processing in SQL, the average EEG data weighted by sales in 30 provinces in mainland China from 2012 to 2019 are provided. Household WG survey data, including household information and average EEG, were collected by distributing questionnaires to 1327 households in Beijing, China. The CEEG dataset will facilitate the advancement of research on household energy consumption, household appliance consumer choice, and the assessment of energy efficiency-related policies.

SOM-Kmeans Based Machine Tools Energy Efficiency Grade Evaluation

SOM-Kmeans Based Machine Tools Energy Efficiency Grade Evaluation

Energy Performance Analysis of Green-Remodeling for Public Buildings under 500 m2

Old buildings over 20 years after completion account for 58.2% of all buildings in Korea. Moreover, buildings built 30 years ago with weak insulation levels have a significant impact on energy consumption in the building sector. Therefore, improving the performance of existing buildings is critical. In addition, green remodeling of old public buildings is currently being implemented in accordance with the mandatory zero-energy construction policy. In Korea, ECO2 based on ISO 13790 and DIN V 18599 is the program used officially to evaluate building energy efficiency ratings and energy independence rates. However, the accuracy of ECO2 is controversial because the cross-use of cooling and heating energy generated in the intermediate stage and the amount of energy used at a specific point in time cannot be analyzed. In addition, previous studies found that the results of a static analysis program showed higher energy performance than those of a dynamic analysis program. In this study, the programs ECO2 and DesignBuilder were used to analyze and compare results of the primary energy consumption (heating, cooling, hot water, lighting, and ventilation) per year for a green-remodeled small public building. Results indicated that the application of the green remodeling elements reduced the primary energy consumption per unit area the most, especially for heating energy. In addition, the change in the building energy efficiency grade through green remodeling improved by two stages from grade 1 to grade 1++ in the case of the ECO2 program, and improved by one stage from grade 1+ to grade 1++ for the DesignBuilder program.

A comprehensive energy efficiency assessment indicator and grading criteria for natural draft wet cooling towers

Energy efficiency evaluation of natural draft wet cooling towers (NDWCTs) is essential to the energy saving process. There is a lack of comprehensive methods that can evaluate and grade the NDWCTs energy efficiency quantitatively. In this study, a comprehensive energy efficiency assessment indicator (CEEAI) including thermal performance, water conservation, and electric saving aspects is proposed. The CEEAI is based on the analysis of NDWCTs mass and heat transfer mechanism. Total 48 actual test reports of the NDWCTs whose water flow rate changes from thousands to hundred thousand tons per hour for test period spans of 16 years, are collected as the database. The CEEAI is validated through statistical analysis and thermodynamics law. Based on the CEEAI and database, an energy-efficiency grading criteria is proposed, the NDWCTs are graded into high, middle and low energy efficiency. Therefore, the energy efficiency of one NDWCT can be clearly observed, which is beneficial for the common researchers to understand the energy efficiency level among all the NDWCTs. In addition, through comparing the CEEAI of different NDWCTs, the energy efficiency gap can be obtained, which provides the optimization guidelines and theoretical support for the improvement of the overall energy efficiency level for the NDWCTs.

Technical requirements analysis of integrated paralleled-loop exhaust air heat pump system applied to ultra-low energy building in different climatic regions of China

Based on the simulation results of the typical rural ultra-low energy building (ULEB) in five different climatic regions of China, three indicative technical parameters for paralleled-loop exhaust air heat pump (PEAHP) R&D which are nominal heating-cooling capacity, maximum required fresh air to return air ratio (MFRR) and system energy efficiency grades were calculated and summarized according to the demand of indoor thermal comforts by using statistic method. The nominal heating-cooling capacities were determined according to the peak loads, which are 6.84-2.01 kW, 5-2.96 kW, 3.9-4.6 kW, 3.08-5.02 kW, and 3.4-0.46 kW in the ULEB of Harbin, Beijing, Shanghai, Guangzhou, and Kunming, respectively. To ensure both thermal comforts and energy conservation, during the heating season, full fresh air supply is suggested in Beijing and the 1:0.5 MFRR is suggested in Harbin, Shanghai, Guangzhou, and Kunming. During the cooling season, the 1:5 MFRR is suggested in Shanghai and Guangzhou, the 1:3, 1:1.5, and 1:0.5 MFRR are suggested in Harbin, Beijing and Kunming, respectively. The PEAHP energy efficiency grades 1~5 are 7.92~11.7, 7.58~11.5, 7.5~11.35, 6.12~9.27, and 4.64~7.03 during the heating season of Harbin, Beijing, Shanghai, Guangzhou, and Kunming, respectively, and are 2.33~3.54, 3.93~5.96, 4.61~6.98, 4.62~6.99, and 2.04~3.1 for the cooling season, respectively.

Effect of energy efficiency labels on household appliance choice in China: Sustainable consumption or irrational intertemporal choice?

Energy consumption has caused severe environmental problems, such as climate change and air pollution. The energy efficiency label is an environmental information policy that provides consumers with energy consumption information of products to change consumers’ choices and guide consumers to green consumption. Current evaluations mainly focus on consumers’ purchase intention toward energy efficiency labels through questionnaire survey and simulation experiment. Our study paper used the real purchase data on China's largest online sales platform to explore consumers’ energy-efficiency home appliance purchase behaviors. This paper found that the energy efficiency labeling policy does not promote consumers’ green consumption behavior, an increase of energy efficiency grade raises the sales of refrigerator by 24.47%, however, the price of the product can negatively regulate the relationship between the energy efficiency grade and the sales. The results of heterogeneity analysis show that when the product price is in the low-price range, consumers will choose high energy-consuming household appliances; only for consumers who purchase mid-to-high-priced products, energy efficiency labeling policies played a guiding role in green consumption. This will cause the energy-saving products more expensive, and consumers are less willing to buy energy-saving products resulting in an energy efficiency paradox. Through further analysis of questionnaire survey data, the results indicate that the energy efficiency paradox is not caused by rational factors, but irrational intertemporal choices. Therefore, accurate assessment of the effect of energy efficiency labels is crucial to promote consumers’ green consumption behavior and mitigate climate change.

Evaluation of the efficiency of Chinese energy-saving household appliance subsidy policy: An economic benefit perspective

China has made great efforts to control energy consumption and reduce environmental pressure in recent decades. In the residential sector, the dramatic increase in the ownership of household appliances has driven the growth of electricity consumption, which calls for effective energy-saving policies. In this study, we exemplified the sales of refrigerators in Beijing, aiming to evaluate the effectiveness of current subsidy policies for stimulating the purchase of energy-efficient household appliances. In specific, we first selected ten pairs of refrigerators from six brands having similar functions, however different in their energy efficiency grades (EEG). By applying a combination of net present value (NPV) difference method and Conversion Method of Electrical Engineering Coefficient, we calculated and compared the changes in the NPV difference and dynamic investment payback period (DIPP) to evaluate the effectiveness of the policy. The results revealed that economic benefits were mainly generated in EEG2; thereby we suggest that the government can cancel subsidies for EEG2 refrigerators, and increase the subsidy amount for EGG1 refrigerators at a potential rate of 24% in the future.

Research and Development of Full Energy Efficiency Grade Motor

This paper proposes the concept of “full energy efficiency grade motor”, explains the characteristics of the full energy efficiency grade motor, and introduces in detail the main techniques and design methods for realizing the full energy efficiency grade motor, and gives a set of design data and test results. The test results show that the designed motor spans three power grades and energy efficiency grades, and its technical parameters fully meet the national standards of each energy efficiency level. This technology can improve motor efficiency, reduce size, reduce tooling and mould, and simplify production management. It can solve the problem of high efficiency and energy saving of the motor in a wide range of variable conditions.

A novel energy efficiency grade evaluation approach for machining systems based on inherent energy efficiency

Characterising the energy efficiency grades of machining systems (MS) is an effective analytical methodology or management tool that helps to establish the high energy-efficient MS. However, the current MS energy efficiency approaches still lack scientific and practical formulation strategies to addresses this issue due to its multi-source and variable energy consumption characteristics. Focusing on this challenge, a new concept of inherent energy efficiency (IEE), which is formed in the design and formation phases of the MS, is proposed. Meanwhile, a novel energy efficiency grade evaluation (EEGE) approach based on IEE is also presented. The proposed EEGE approach not only can evaluate the MS energy efficiency grades, but also can reveal the MS high energy-efficient intervals. According to the analysis of IEE in MS, the EEGE approach is developed in three steps: (i) the establishment of IEE evaluating indicator system from both inherent energy utilisation (IEU) and inherent specific energy (ISE), (ii) the acquisition of the IEE, and (iii) the development of a quantitative method for the EEGE in MS. Finally, a case study of energy efficiency grade evaluation and analysis for an XK714D CNC milling machining centre is examined, illustrating the practicability of the proposed method.

An Energy Efficiency Indicator and Grading of Shell-and-Tube Heat Exchangers

The shell-and-tube heat exchanger is the most commonly used heat exchange equipment in the industry. Whether shell-and-tube heat exchangers are energy-saving is of great significance for the efficient using of energy. Therefore, the corresponding evaluation system and index are needed for evaluating the heat transfer process in the shell-and-tube heat exchanger. In this paper, based on Kern method, the energy efficiency evaluation index of shell-and-tube heat exchanger suitable for oil-water working medium is derived. And the relevant database is used to obtain the overall energy efficiency distribution of the industry, which is subject to the normal distribution, finally according to the overall energy efficiency distribution, the energy efficiency of the shell-and-tube heat exchanger is graded.

A comparative analysis of data-driven methods in building energy benchmarking

A reasonable building energy efficiency benchmarking program plays an important role in energy consumption control and supervision. Previous studies have focused on the process of establishing a single benchmarking method, but few have compared the performances and outcomes of different methods. To fill this gap, this paper selects three benchmarking methods—multiple linear regression (MLR) based on Energy Star, stochastic frontier analysis (SFA) and the descriptive statistics method (DSM) based on the national energy consumption standard in China—to develop benchmarking models. We demonstrate each method using data on the energy and building characteristics of 45 four- and five-star hotel buildings located in Chongqing, China. To compare the consistency, robustness and explanatory ability of the three methods, we first utilize the Spearman rank correlation analysis to test whether these methods have consistent energy efficiency ranks and then present Sankey diagrams to further reveal the interactions of the estimated energy efficiency grades obtained from the three methods. It is found that the results of DSM and SFA are most consistent, while MLR vs. SFA and MLR vs. DSM present significant differences in evaluating building energy performance. In addition, DSM is more robust for evaluating the ranks of sampled buildings, while SFA is more robust for evaluating energy efficiency grades. Furthermore, we discuss the explanatory ability of each method. In addition to the building characteristics, the design and operational characteristics of the HVAC system have great effects on building energy consumption. Finally, we present suggestions for policy-makers regarding the development and implementation of the building energy benchmarking program in Chongqing and for the management of buildings with different energy performances to further improve the energy efficiency.

Environmental life cycle assessment and techno-economic analysis of domestic hot water systems in China

In this study, a cradle-to-grave life cycle assessment was conducted on several typical domestic hot water systems across five climatic regions of China. Variations of the climate and energy supply in these regions and the energy efficiency grade of domestic hot water systems were also taken into consideration. The results suggest that evacuated tube solar systems are highly energy-efficient and low-cost, except in the region with the weakest solar radiation. Electric systems are extremely energy-intensive and uneconomical for domestic hot water use, although they have the least human and ecological toxicity potentials. Solar and air-source energy systems save energy; however, they use more materials and cause more human and ecological toxicity. From the severe cold region to the hot summer and warm winter region, the heat load of domestic hot water increases by 59%, resulting in an increase of 58–230% in primary energy demand. Accordingly, the environmental impacts of domestic hot water systems increase in varying degrees; however, few impacts decrease due to the different emission factors of different power grids. The raw materials used in the manufacture of domestic hot water systems and the energy required for the use of the systems are the most important contributors to all environmental impacts. The scenario analysis indicates that 24.5% of the primary energy demand and 25.7% of greenhouse gas emissions owing to domestic hot water use in China can be reduced by improving the energy efficiency, prompting the use of renewable energy sources, and reducing the usage of materials for domestic hot water systems, as the human and ecological toxicity potentials will increase by 0.1% and 10%, respectively, due to the increasing use of certain materials.

Discussion on Energy Efficiency Grades of Evaporative Cooling Air Conditioning Equipment

In this paper, problems and inconvenience of existing parameters which are used to describe the energy efficiency of the evaporative cooling equipment were discussed. In accordance with the principle of the psychrometric chart, different energy efficiency grades of the evaporative cooling equipment were analyzed. On this as is, 5 energy efficiency grades for evaporative cooling equipment were put forward, combined with the psychrometric chart. In addition, the process and reasonableness of the grading were introduced.

National standard research on the minimum allowable values of energy efficiency and energy efficiency grades for air cleaners

This paper demonstrates the background and the significance on the national standard research on the minimum allowable values of energy efficiency and energy efficiency grades for air cleaners. The study also introduces the general thinking and principle of the standard development the determination of the minimum allowable values of energy efficiency, the classification of the energy efficiency grades for air cleaners, as well as the testing methods, which would help to eliminate the production of the high energy consumption air cleaner products, and effectively improve their level of the energy efficiency through the developing and implementation of the national standard.

농촌 마을회관 제로에너지 건축물 구축을 위한 에너지 성능 분석 연구 - 충남 태안군 정죽4리 마을회관을 중심으로 -

In this study, we survey the 2 buildings at the Central 1 and 8 buildings at the Central 2, which are divided by each climate region in the rural regions. Major heat loss factors are 47% loss of the outer shell including outer wall, roof , and bottom, 30% loss through window, and 23% loss through crevice wind. We analyze the energy simulation of ECO2 program to construct a zero energy building regarding village hall located in Jung Juk 4-le at Centeral 2. We simulate the primary energy requirement regarding village hall and the simulated results show the 265.3 kWh/m²･a and it may estimate `2` energy efficiency grade. The energy requirement regarding village hall is the 183.2 kWh/m²･a when the passive technology are applied in village hall. We research total amount of energy requirement in village hall when the passive and active technologies such as solar cell with 3kW and solar thermal with 20m², geothermal power with 17.5kW. The simulated results show the improved energy efficiency certification grade with 1+++ due to the reduced primary energy requirement with 73% when passive technology including 3kW of solar panel is applied and the energy independence rate is 54%, which is estimated to be 4th grade of zero energy buildings. The order of energy consumption are solar panel, solar thermal, and geothermal power under applied passive technology in the building. In order to expand the zero energy building, it is necessary to introduce the zero energy evaluation system in the rural region.

Grading buildings on energy performance using city benchmarking data

As the effects of anthropogenic climate change become more pronounced, local and federal governments are turning towards more aggressive policies to reduce energy use in existing buildings, a major global contributor of carbon emissions. Recently, several cities have enacted laws mandating owners of large buildings to publicly display an energy efficiency rating for their properties. While such transparency is necessary for market-driven energy reduction policies, the reliance on public-facing energy efficiency grades raises non-trivial questions about the robustness and reliability of methods used to measure and benchmark the energy performance of existing buildings. In this paper, we develop a building energy performance grading methodology using machine learning and city-specific energy use and building data. Leveraging the growing availability of data from city energy disclosure ordinances, we develop the GREEN grading system: a framework to facilitate more accurate, fair, and contextualized building energy benchmarks that account for variations in the expected and actual performance of individual buildings. When applied to approximately 7500 residential properties in New York City, our approach accounts for the differential impact of design, occupancy, use, and systems on energy performance, out-performing existing state-of-the-art methods. Our model and findings reinforce the need for more robust, localized approaches to building energy performance grading that can serve as the basis for data-driven urban energy efficiency and carbon reeduction policies.

Automatic testing system to evaluate the energy efficiency of electric storage water heaters

Background: The energy efficiency of electric storage water heaters is a concern for enterprises and customers because it is beneficial for energy saving. To decrease the workload of testing personnel and improve the testing efficiency, an automatic testing system for evaluating the energy efficiency performance of electric storage water heaters has been designed. Methods: The complete testing system includes a water supply subsystem, hot water outlet subsystem, hardware subsystem, and software subsystem. An application program was developed using Visual Basic to acquire the sensor data and transmit it in real time to a database server. The energy efficiency evaluating process was controlled by the application software,by combining the data acquisition technology, communication technology, and program logical control technology. Results: The designed system can run automatically and achieve reliable tests, two important parameters including the standing loss per 24 h and the hot water withdrawal rate were obtained. Conclusion: This system can be applied to evaluate the energy efficiency grades of electric storage water heaters.

An energy efficiency grading system for mobile applications based on usage patterns

In selecting a mobile application, the absence of the power-related information obstructs the user from making the smart decision. To handle this problem, we propose an energy efficiency grading system for mobile applications. The system measures the power consumption of the applications over the test scenarios where the representative usage patterns of users are considered. After that, the system rates the grades of the applications based on the measured power consumption. Therefore, the user can refer to the appropriate energy efficiency grade of the applications by taking into account own usage pattern. Moreover, the proposed system provides a label for the energy efficiency grades, so the user can intuitively understand the power-related information of the applications. The evaluation of the system shows that it can help the user to select a better application among interchangeable applications.

Research on the minimum allowable values of energy efficiency and standard of energy efficiency grades for precipitator in power industries

This paper elaborates the necessity and the feasibility of the standard research on the minimum allowable values of energy efficiency and energy efficiency grades for precipitator in China’s power industries. It does a research on the energy efficiency grades, minimum allowable values of energy efficiency and its test methods for precipitator in power industries.