Energy Conservation Evaluation Research Articles

Development of a variable refrigerant flow system emulator to host the second World Championship in Cybernetic Building Optimization

This paper introduces an emulator developed to assess the operational characteristics of variable refrigerant flow (VRF) for the second World Championship in Cybernetic Building Optimization (WCCBO). The emulator utilizes BACnet communication and provides a realistic simulation for evaluating energy conservation and comfort in buildings with VRF systems. Herein, we discuss the building specifications for calculation, operation of the emulator, calculation method for the vertical temperature distribution, dissatisfactory rate calculation, and consideration of championship rules. Notably, a thermal preference model was developed for predicting the thermal sensation of occupants and adjusting the dissatisfaction rate based on their ability to control the indoor environment. In addition, we developed a method for calculating the total scores during the WCCBO and devised a suitable network structure for score registration. The results of this study highlight the importance of personal control and impact of drafts on thermal comfort. This paper presents a meta-level methodology to determine the best operation for each specific VRF system for a future world championship, whose planning is underway and will be conducted to accumulate information on optimal operations.

LogTODIM framework for MAGDM with neutrosophic sets: Energy conservation and emission reduction case

The significant acceleration of China’s urbanization process has greatly promoted economic development. At the same time, the massive construction of urban buildings has also caused many problems such as environmental pollution and increased energy consumption. Therefore, in architectural design, it is particularly important to pay attention to the sustainable development of the environment, handle the relationship between good people and nature under the guidance of the concept of green development, and focus on the recycling of resources. Focusing on resource utilization in architectural design and based on certain planning can better control the construction process of urban buildings, save energy consumption, reduce construction costs, and contribute to the green development of cities. The comprehensive evaluation of energy conservation and emission reduction of construction projects is a classical MAGDM problems. Recently, the Logarithmic TODIM (LogTODIM) method has been employed to cope with MAGDM issues. The single-valued neutrosophic sets (SVNSs) are used as a tool for characterizing uncertain information during the comprehensive evaluation of energy conservation and emission reduction of construction projects. In this paper, the single-valued neutrosophic number Logarithmic TODIM (SVNN-LogTODIM) method is built to solve the MAGDM under SVNSs. In the end, a numerical case study for comprehensive evaluation of energy conservation and emission reduction of construction projects is given to validate the proposed method.

Binary decanoic acid/polyethylene glycol as a novel phase change material for thermal energy storage: Eutectic behaviors and energy conservation evaluation

This work developed a novel decanoic acid/polyethylene glycol binary eutectic (DA-PEG) phase change material (PCM) for thermal energy storage, wherein the mass ratio of DA and PEG was 1:1. DSC results indicated that DA-PEG eutectic had a suitable phase transition temperature of 22.9 °C for building thermal comfort, and its latent heat of 173.9 J/g was relatively large. Moreover, DA-PEG eutectic PCM had a superior crystallinity as compared to pure PEG, which was confirmed by the results in terms of supercooling degree, relative exothermic capacity and crystallization kinetics. ATR-FTIR and Raman spectra were used to reveal the mechanism behind. It turned out that the improved crystallization behaviors of PEG were achieved by the promoting effect of the intermolecular hydrogen bonding between DA and PEG on the ordered arrangement of PEG long chain. Furthermore, DA-PEG eutectic PCM presented good thermal and chemical stability in long-term use. Besides, energy and environmental assessment suggested that DA-PEG eutectic exhibited high cost performance and great potentials for energy conservation and emission reduction used in solar passive building.

Oscillation period of the truncated simple pendulum

In this manuscript, a non typical kind of simple pendulum called Truncated Simple Pendulum is analysed to obtain its oscillation period, frequency, and angular frequency. It is easily derived that its motion can be viewed as the concatenation of two pendular movements with different lengths, contributing each one to half of the period of the complete oscillation. An analytical formulation is derived and corroborated with an experiment showing high agreement. This experiment could be interesting as a proposed exercise for the students or as a laboratory practical work. Besides, the gravity acceleration can be determined from each singular experiment and averaged to obtain it with lesser experimental error. In addition, it can be used to evaluate energy conservation theorem and small angle approximation (Law of isochronism) for the pendular oscillation. The level of the manuscript makes it appropriate for undergraduate students and introductory physics courses.

Feasibility of condensate water recycle of split air handling unit in Chinese University buildings

Recycling the condensate water of the air conditioner could be explored as an alternative water source to contribute to building the green campus. This paper explored the condensate water production through actual measurement based on a split air handling unit (SAHU) in a university building. Then, the statistical analysis was used to analyze the recycling feasibility and the impact factors of the condensate water production in 31 Chinese provincial capital cities to obtain the recycling potential map of the condensate water generated from a SAHU. Results showed that: (1) In the measurement, the amount of condensate water produced by a single split air conditioner was 1.6 kg from 12:40 to 13:40. Therefore, the daily output of condensate water of the air conditioner with the university operation schedule could reach 52.99 kg during the main air-conditioning season. (2) Among the 31 provincial capital cities in China, the largest condensate water outputs could be found in the Hot Summer and Warm Winter zone and the Hot Summer and Cold Winter zone, with an average monthly output of 1600 kg and 1100 kg, respectively. (3) Regression analysis showed that the dry-bulb temperature and dew point temperature of outdoor air had the highest positive and significant influence on condensate water production. The objective of this study is to provide theoretical guidance for the design and energy conservation evaluation of the feasibility of SAHU condensate water recycling in universities.

Evaluation of green technology innovation efficiency in a regional context: A dynamic network slacks-based measuring approach

As green technology innovation efficiency is considered an effective indicator to evaluate energy conservation and emission mitigation, the question of how to estimate it has become a hot topic. Research primarily calculates the cross-section efficiency from a static perspective or the network efficiency alone; however, few studies have considered dynamic characteristics and the network structure of the innovation process simultaneously. To address this gap, this paper employs slacks-based dynamic network data envelopment analysis to calculate the overall, intertemporal, and divisional green technology innovation efficiency covering China's 30 provinces over 2012–2019. The results indicate that (1) a strong spatial dependence of efficiency scores exists, accounting for 60 % of the aggregate statistics. (2) China's overall scores are low, and inefficient regions need to improve efficiency by at least 31.41 % to become efficient. (3) Economically developed regions, provinces with advanced manufacturing, and nonresource-based areas have relatively high scores. (4) The period scores fluctuate greatly up and down around the overall scores, showing a significant spatial imbalance within consecutive multiple periods. (5) Regarding divisional scores, the internal structure of green technology innovation efficiency in China is inferior in R&D and superior in commercialization. Generally, policy-makers should improve local conditions for green technology innovation efficiency.

Understanding the energy consumption of information and communications equipment: A case study of schools in Taiwan

Information and communications technology (ICT) equipment is often used to help conserve energy, but such equipment also requires energy to operate. This study investigated the energy consumption of ICT in 28 secondary schools (SSs) and 98 elementary schools (ESs) in Taiwan. The average annual energy consumption of ICT equipment is 28,162 kWh and 20,888 kWh per SS and ES, respectively; per unit floor area, this is estimated to be 60.5 and 27.5 Wh/m2/year, respectively. ICT accounted for 7.3%–7.7% of the total energy consumption of each school. Projection, computer, and network equipment together account for more than 90% of the total electricity consumed by ICT equipment. The total energy consumption of ICT equipment is positively correlated with school type and size. The study established three multiple regression models to investigate the total energy consumption of ICT equipment per school, per class, and per student, and the models all exhibited statistical significance. The energy consumption is highly correlated with usage time and power dissipation. Equipment procurement and energy consumption management play key roles in the energy conservation. This study may serve as references for school administrators evaluating energy conservation effectiveness.

Large scale energy analysis and renovation strategies for social housing in the historic city of Venice

Social houses built after the Second World War to accommodate workers and low-income families represent one of the major energy consumers and greenhouse gas emitters in the residential sector. Plans for their renovation are underway in all European countries, and the process is more complicated for Italian cities due to the lack of space and the large number of historical buildings. This study addresses this challenge by proposing a methodology to renovate a low-income district in the city of Venice using CityBES to model and evaluate energy conservation measures. CityBES is a web-based tool that allows users to employ urban building energy modeling for large-scale energy and retrofit analyses of building stocks. In the case study conducted for Venice’s Santa Marta district, due to the particular context, four common energy conservation measures covering both the building envelope and heat generation boilers have been applied. The evaluation of energy-saving performances at the district level showed that the four measures together achieved 67% energy savings, an abatement in energy cost equal to 67%, and annual carbon dioxide emissions reduction of 1.1 MtCO2. The case study demonstrates a method and workflow replicable for energy retrofit analysis of building stocks in other historical districts.

Urban building energy model: Database development, validation, and application for commercial building stock

Achieving citywide building energy reduction goals require extensive understanding of energy use at scale, which is challenging due to scarce and disparate data. Despite attention to urban building energy models (UBEM), unexplored aspects and missing details in this emerging field have remained, including further exploring non-homogenous commercial buildings, providing a detailed structure to create UBEMs for replication purposes, and developing methods to mitigate data scarcity and dependency. In this study, a structure is proposed using commercial buildings in Pittsburgh, Pennsylvania. We provide a description of an archetype library with relevant sources to improve reproducibility and describe a novel framework to create a database focusing on façade reconstruction through photogrammetry and image processing. For our UBEM, twenty archetypes that comprised eight commercial use types were identified. The average annual energy use intensity was estimated between 74 and 1302 kWh/m2 for different use types. The simulation results also showed discrepancy in energy use of the buildings with similar use types. Validating the results utilizing actual data revealed an overall 7% error. Employing the model to evaluate energy conservation strategies showed energy use reduction of 2–5% for the entire stock. Outcomes of this research can aid policy makers in instituting energy goals and efficiency regulations.

Capital Allocation Efficiency Evaluation of Energy Conservation and Environmental Protection Enterprises in the Yangtze River Delta of China

Capital Allocation Efficiency Evaluation of Energy Conservation and Environmental Protection Enterprises in the Yangtze River Delta of China

Comprehensive Evaluation Method of Office Building Energy Consumption Based on Improved Multi-index

In view of the imperfection in the selection of energy consumption characteristics and energy conservation evaluation methods, this paper proposes an energy consumption analysis and energy conservation evaluation method suitable for office buildings. Through the analysis of office building energy consumption monitoring layer data, establishing standard of building energy consumption data sets, including office building day by day, month by month, year after year way of energy consumption and heating and cooling is analyzed, and aiming at the problem of building energy efficiency evaluation index weights are difficult to determine the, combined with the feature of energy consumption was proposed to build multiple indexes comprehensive evaluation of energy consumption. Through the example of office building, the evaluation results are verified, which proves that this method can evaluate the energy consumption of buildings reasonably and feasible, and provides a new idea for the comprehensive evaluation of building energy conservation.

An empirical study of willingness to renewable energy installation using importance-performance analysis: the case of Taiwan

ABSTRACTGlobal warming and climate change issues, coupled with excessive energy consumption, has already had dramatic effects on the survival of the human race. To support electricity generation from renewable sources, most governments have instituted different mechanisms to raise the investment incentive to renewable energy. Past researches mainly focused on evaluation of energy conservation. However, few researchers studied in characteristics of renewable energy installers’ willingness. Due to Importance-performance analysis (IPA) is ease of application, this study utilizes IPA based on the respondents’ perception to explore which factors, including administrative support and governmental reward policy to renewable energy installation, and provide valuable information for government energy policy decision-makers. The study shows that the government urgently to solve administrative support includes eliminating regulatory barriers, setting a cross-ministry supporting, enhancing administrative efficiency; in addition, governmental reward policy measures need to be resolved to include reasonable acquisition rates, and effective incentive policy for R&D.

Evaluation of the feasibility of distributed energy supply system for existing multi-family housing in Nagoya City

The possibility of introducing distributed energy system consisting of combining heat and power generation (CHP) for existing multi-family housing is discussed in order to make an academic ground for calling for the spread of distributed energy systems in existing multi-family houses. Case study was conducted to evaluate energy conservation effect of the distributed energy supply system and obtain the findings concerning on its feasibility. The case study was focusing on all municipal multi-family housing in Nagoya city, Japan, and it was evaluated based on primary energy consumption reduction, CO2 emission reduction, simple pay-back period, and recurring expenses merit by introducing the system. Annual energy consumption was estimated for nine typical municipal multi-family houses with different average occupied floor area and number of dwelling for each individual building unit. Based on the results of the case study, it was found that the effect of the distributed system varies depending on the average occupied floor area and the number of residences, and the generator capacity of CHP. In addition, when assuming adapting a distributed energy supply system into a type of housing has occupied floor area of 30m2-50m2 per a dwelling that accounts for 83.5% of the total municipal housing in Nagoya, at least the overall reduction of 16.7% CO2 emission reduction rate could be expected.

Estimation and Analysis of Energy Conservation and Emissions Reduction Effects of Warm-Mix Crumb Rubber-Modified Asphalts during Construction Period

In order to solve the serious environmental problems caused by the rapid increase in the number of waste tires and unproper storage of waste tires, modifying the asphalt mix for roadway pavement by adding rubber crumb from recycled waste tires is one of the highly effective approach to solve the problem and can achieve the sustainable use of rubber resources. The application of warm-mix crumb rubber-modified asphalt (CRMA) overcomes some issues of the hot-mix CRMA, such as high temperature and high energy consumption. However, there is a lack of estimation methodology for the energy conservation and emission reduction during the production process of warm-mix CRMA. This study develops the estimation models for the evaluation of energy conservation and emissions reduction during different production stages of waste rubber powder, asphalt, CRMA, hot-mix CRMA, and warm-mix CRMA. A list for gas emissions during the mixing and paving process of CRMA mixtures was established through the simulated mixing measurement and paving site measurement. The results show that for each metric ton of CRMA mixture produced, warm mixing can reduce energy consumption by 18~36% and decrease gas emissions during different stages by 15~87% compared to hot mixing. The Evotherm warm-mix CRMA mixture with DAT as warm mix agent (Ev-DAT warm-mix CRMA mixture) is more energy-efficient by saving approximately 108.56 MJ of energy and reducing gas emissions during mixing and paving by at least 32% and 73%, respectively. This model can improves the technical standard of warm-mix CRMA and the energy conservation assessment.

Research on China Airport Performance Evaluation of Energy Conservation and Emission Reduction Based on Data Envelopment Analysis Model

With study on 15 China airports (groups) that were funded by the special funds for energy conservation and emission reduction in civil aviation, using the SE-DEA model as research tool, the energy conservation and emission reduction efficiency of the sampled enterprises were analyzed. More than half of the airport units did not achieve DEA efficiency, mainly resulted from the simultaneous technical inefficiency and scale inefficiency. All units that failed to meet the standard should increase the quantity of electricity conservation. In the future, the scale of project output should be expanded in resource allocation in the development of China green airports, strengthening research and application of new technology and new method. This study is of certain guiding significance for the scientific allocation of financial resources and the construction of green civil aviation.

Investigation of Effect of Biomass Torrefaction Temperature on Volatile Energy Recovery Through Combustion

Biomass torrefaction is a mild pyrolysis thermal treatment process carried out at temperatures between 200 and 300 °C under inert conditions to improve fuel properties of parent biomass. Torrefaction yields a higher energy per unit mass product but releases noncondensable and condensable gases, signifying energy and mass losses. The condensable gases (volatiles) can result in tar formation on condensing, hence, system blockage. Fortunately, the hydrocarbon composition of volatiles represents a possible auxiliary energy source for feedstock drying and/or torrefaction process. The present study designed a low-pressure volatile burner for torrefaction of pine wood chips and investigated energy recovery from volatiles through clean co-combustion with natural gas (NG). The research studied the effects of torrefaction pretreatment temperatures on the amount of energy recovered for various combustion air flow rates. For all test conditions, blue flames and low emissions at the combustor exit consistently signified clean and complete premixed combustion. Torrefaction temperature at 283–292 °C had relatively low volatile energy recovery, mainly attributed to higher moisture content evolution and low molecular weight of volatiles evolved. At the lowest torrefaction pretreatment temperature, small amount of volatiles was generated with more energy recovered. Energy conservation evaluation on the torrefaction reactor indicated that about 27% of total energy carried by the exiting volatiles and gases has been recovered by the co-fire of NG and volatiles at the lowest temperature, while around 19% of the total energy was recovered at the intermediate and highest torrefaction temperatures, respectively. The energy recovered represents about 23–45% of the energy associated with NG combustion in the internal burner of the torrefaction reactor, signifying that the volatiles energy can supplement significant amount of the energy required for torrefaction.

Mathematical model of energy conservation evaluation of passive building based on fuzzy clustering algorithm

When evaluating the energy conservation effect of passive buildings, the traditional gray comprehensive evaluation model cannot comprehensively analyze the building's own factors, which leads to lower accuracy of analysis. Mathematical model of energy conservation evaluation of passive building based on fuzzy clustering algorithm is designed, which uses the analytic hierarchy process to determine the weight of the energy conservation evaluation index of passive building. The system of energy conservation indicators for passive buildings is constructed to calculate fuzzy similarities between different evaluation indicators and to calculate them. Through the clustering of the calculation results, the energy conservation evaluation results of the passive building are obtained. The experimental results show that the designed model can effectively evaluate the energy conservation effect of passive buildings, and its generalization ability is better. The average accuracy of the evaluation is as high as 98%, and the evaluation rate is as high as 96%. The average time-consuming value of the eight passive buildings is only 540.54 s. It has the advantage of high evaluation accuracy and high efficiency.

東京電力技術開発センターの省エネルギーシステム （第16報）省エネルギーシステムの20年間の運転・運用実績

東京電力技術開発センターの省エネルギーシステム （第16報）省エネルギーシステムの20年間の運転・運用実績

東京電力技術開発センターの省エネルギーシステム （第17報）２１年間の運用実績および自動制御設備の保全状況

東京電力技術開発センターの省エネルギーシステム （第17報）２１年間の運用実績および自動制御設備の保全状況

C-11 ドームシティガスビルの省エネルギーと環境負荷低減の実測結果

C-11 ドームシティガスビルの省エネルギーと環境負荷低減の実測結果