With the advent of the era of big data,buildings have become not only energy-intensive but also data-intensive.Data mining technologies have been widely utilized to release the values of massive amounts of building op...With the advent of the era of big data,buildings have become not only energy-intensive but also data-intensive.Data mining technologies have been widely utilized to release the values of massive amounts of building operation data with an aim of improving the operation performance of building energy systems.This paper aims at making a comprehensive literature review of the applications of data mining technologies in this domain.In general,data mining technologies can be classified into two categories,i.e.,supervised data mining technologies and unsupervised data mining technologies.In this field,supervised data mining technologies are usually utilized for building energy load prediction and fault detection/diagnosis.And unsupervised data mining technologies are usually utilized for building operation pattern identification and fault detection/diagnosis.Comprehensive discussions are made about the strengths and shortcomings of the data mining-based methods.Based on this review,suggestions for future researches are proposed towards effective and efficient data mining solutions for building energy systems.展开更多
The coupling and complexity of railway train/tunnel system are further aggravated by increasing train speed,which produces a series of aerodynamics problems,such as aerodynamic drag,slipstream,pressure wave and micro ...The coupling and complexity of railway train/tunnel system are further aggravated by increasing train speed,which produces a series of aerodynamics problems,such as aerodynamic drag,slipstream,pressure wave and micro pressure wave.Aerodynamic effects of tunnels will result in a significant increase in train energy consump-tion,shorten life of railway train/tunnel system,and increase maintenance cost.This paper provides a review of aerodynamics of railway train/tunnel system.Challenges in railway train/tunnel system aerodynamics and their related factors are discussed firstly.Aerodynamic performance and flow field characteristics of trains in tunnels are presented.Relationship of aerodynamic effects and parameters of railway train/tunnel system,and the control methods for reducing aerodynamic effects in tunnels are explained.A traffic safety evaluation of the train in tunnels,such as vehicle body structure,passengers’ear comfort,etc.,is introduced and analysed.Finally,future outlooks and research topics are proposed.展开更多
In the past several years,thermal comfort,especially development and application of thermal comfort model,has been a research focus of building environment.Since the 1970s,a series of thermal comfort models based on p...In the past several years,thermal comfort,especially development and application of thermal comfort model,has been a research focus of building environment.Since the 1970s,a series of thermal comfort models based on people’s thermal sensation to environment have been established,and gradually became an important part of the field of thermal comfort research.In this review,the existing thermal comfort models are summarized from various perspectives,such as models applied in different environments like sleeping environment and outdoor environment.Besides,models used for different groups people,such as elderly and different races are discussed.In the part,adaptive models are mentioned.In additions,data-driven models were reviewed.This paper introduced the advantages and disadvantages of each model.Based on the above review,future research work of thermal comfort model is proposed.展开更多
Renewable energy has become an important choice to solve the energy crisis and environmental problems.A sustainable development needs policies and strategies policies,which can improve energy efficiency and reduce gre...Renewable energy has become an important choice to solve the energy crisis and environmental problems.A sustainable development needs policies and strategies policies,which can improve energy efficiency and reduce greenhouse gas emissions.By collecting the research results released by relevant statistical departments and authoritative institutions,this paper summarizes the international energy development situation,systematically combs the energy development situation of the European Union,United States,Australia,India,Brazil.The development trend of wind,solar,biomass,geothermal,ocean,and hydrogen energy have been analyzed.In addition,this paper proposes that China should draw up its own development path of renewable energy from international development experience,and actively explore renewable energy policies and strategies adapted to different stages of development.展开更多
This paper systematically describes the technical principles,evaluation indicators,system forms and research progress of air-side evaporative cooling air conditioning systems,water-side evaporative cooling air conditi...This paper systematically describes the technical principles,evaluation indicators,system forms and research progress of air-side evaporative cooling air conditioning systems,water-side evaporative cooling air conditioning systems and freon-side evaporative cold coagulation heat air conditioning systems of Data center.In order to reduce the energy consumption of the refrigeration and air-conditioning system in the Data center,the applica-tion conditions and scenarios of the different forms of evaporative cooling air-conditioning systems should be considered comprehensively.Therefore,it is very important that the renewable energy-dry air can be used to the greatest extent.These efforts would contribute to China’s 2030"Carbon Peak"and 2060"Carbon Neutral."展开更多
The energy consumption in buildings for heating,ventilation,and air-conditioning is increasing with the in-creasing demand for thermal comfort.Thermal energy storage with phase change material(PCM)has attracted growin...The energy consumption in buildings for heating,ventilation,and air-conditioning is increasing with the in-creasing demand for thermal comfort.Thermal energy storage with phase change material(PCM)has attracted growing attention for its role in achieving energy conservation in buildings with thermal comfort.This paper investigates the effect of PCM on the heat transfer rate in a building wall and the role of PCM on the indoor thermal comfort of the building.Two models of building wall fragments were developed for the experimental study.In one model,tests were conducted for different positions of the PCM layer in the building wall to identify the optimal position of the PCM layer inside the wall.In another model,tests were carried out integrating PCM,air gap,and other conventional building materials(brickbat and sand),one at a time,to investigate the role of PCM on the heat transfer rate in the building wall fragment.The results show that placing the PCM layer closer to the heat source gives a low-temperature gain of the cold water bath(indoor state)as compared with the PCM layer near the heat sink.With PCM,the temperature rise of the cold water bath(indoor state)of the building wall fragment was the lowest,and the slope of the temperature rise of the cold water bath becomes steadier with time i.e.,fewer temperature fluctuations.There was a significant time delay for the cold water bath to reach a given temperature.The heat required for a unit degree increase in the temperature of the cold water bath was higher and the peak heat flux of the wall was lower relative to the other building materials.展开更多
With the continuous deepening of China’s rural construction and development,people’s living conditions are improved day by day,while accompanied by energy and environment crisis issues.This paper mainly analyzes the...With the continuous deepening of China’s rural construction and development,people’s living conditions are improved day by day,while accompanied by energy and environment crisis issues.This paper mainly analyzes the energy consumption pattern and the indoor environment of rural households in China and discusses the energy-saving optimization strategies for improving the thermal environment of buildings.Questionnaire surveys and field surveys were conducted in three villages in Guanghan,China.The measurement results show that the annual indoor temperature range of the region in the summer is 15-31℃and the relative humidity range is 34%-96%.The average indoor temperatures in summer and winter are 28℃and 16℃respectively.The indoor thermal environment of rural buildings is usually poor and cannot meet the requirements of Chinese standards.At the same time,the architectural design and energy consumption pattern of rural households are different from those in urban areas as countryside has unique characteristics.Finally,we put forward certain energy-saving improvement measures at the end of the article.展开更多
Trombe wall and phase change materials(PCMs)are two effective ways to regulate indoor thermal comfort.However,Trombe wall surfers from overheating in summer and PCMs suffer from low heat transfer rate caused by the li...Trombe wall and phase change materials(PCMs)are two effective ways to regulate indoor thermal comfort.However,Trombe wall surfers from overheating in summer and PCMs suffer from low heat transfer rate caused by the limited thermal conductivity.To compensate the shortcomings of the two methods,this paper proposed a Trombe wall system integrated with PCMs.Based on a light-weight building envelope in Changsha,China,the thermal comfort of 10 kinds of Trombe wall systems with PCMs with a melting temperature of 18-28℃ were studied.Taking the integrated indoor discomfort duration(I_(D)),integrated indoor discomfort degree-hour(I_(DH)),indoor air temperature(T_(in)),PCM liquid fraction(γ)and heat flux across wall(q)as evaluation indexes,the indoor thermal comfort was assessed in hot summer and cold winter region.Results show that the Trombe wall helped PCMs complete the phase change process effectively.Trombe wall with PCM25 next to the wall inner surface possessed the lowest annual I_(D) and I_(DH),as 2877 h and 12,974℃·h,respectively.Compared with the values in a traditional building,the I_(D) and I_(DH) were reduced by 7.01% and 14.14%.In order to give full play to the heat storage and heat release of the Trombe wall with PCMs,PCMs with phase change temperature 7℃ lower than the peak ambient temperature in summer or 8℃ higher than the winter night temperature was recommended according to regional climate conditions.展开更多
Various systems and technologies have been developed in recent years to fulfil the growing needs of high-performance HVAC systems with better performance of energy efficiency,thermal comfort,and occupancy health.Inten...Various systems and technologies have been developed in recent years to fulfil the growing needs of high-performance HVAC systems with better performance of energy efficiency,thermal comfort,and occupancy health.Intensified conditioning of human occupied areas and less intensified conditioning of surrounding areas are able to effectively improve the overall satisfaction by individual control of personalized micro-environments and also,achieve maximum energy efficiency.Four main concepts have been identified chronologically through the devel-opment of personal environmental conditioning,changing the intensified conditioning area closer to the human body and enhancing conditioning efforts,namely the task ambient conditioning(TAC)system,personal envi-ronmental control system(PECS),personal comfort system(PCS),and the personal thermal management(PTM)system.This review follows a clue of the concept progress and system evaluation,summarizes important findings and feasible applications,current gaps as well as future research needs.展开更多
Solar Aided Power Generation(SAPG)is the most efficient and economic ways to hybridise solar thermal energy and a fossil fuel fired regenerative Rankine cycle(RRC)power plant for power generation purpose.In such an SA...Solar Aided Power Generation(SAPG)is the most efficient and economic ways to hybridise solar thermal energy and a fossil fuel fired regenerative Rankine cycle(RRC)power plant for power generation purpose.In such an SAPG plant,the solar thermal energy is used to displace the extraction steam by preheating the feedwater to the boiler.The displaced/saved extraction steam can,therefore,expand further in the steam turbine to generate power.The research and development of the SAPG technology started in the 1990s.This paper is trying to reviews and summarises the progress of research and development of the SAPG plant technology in last almost 30 or so years,including the technical and economic advantages of SAPG over other solar thermal power generation tech-nologies(e.g.solar alone power generation),various modelling techniques used to simulate SAPG perforamnce,impacts of SAPG plant’s configuration,size of solar field and strategies to adjust mass flow rate of extraction steam on the plant perforamnce,exergy analysis of SAPG plant and operation strategies to maximise plant’s economic returns etc.In addition,the directions for future R&D about SAPG technology have been pointed/proposed in this paper.展开更多
Enhancing the energy efficiency of structures has been a staple of energy policies.The key goal is to slash elec-tricity usage in order to minimize the footprint of houses.This goal is sought by putting restrictions o...Enhancing the energy efficiency of structures has been a staple of energy policies.The key goal is to slash elec-tricity usage in order to minimize the footprint of houses.This goal is sought by putting restrictions on the design specifications with respect to the properties of the raw materials and components as well as the exploitation of sustainable sources of energy.These facts for the basis for zero-energy building(ZEB)being established.This novel technology has faced several obstacles impeding its commercialization and future advancement.This inves-tigation therefore holistically explored and evaluated the state of zero energy building and factors impeding their commercialization.The review further proposed some suggestion in terms of technology that can be considered by the sector to augment existing technologies.Similarly,the investigation touched on the effect of occupant’s character in zero energy structures.Policies in terms of government subsidies and tax rebates were recommended to encourage more investors into the sector.Finally,the perception of zero energy building being more expensive compared to the traditional structures can equally be curbed via efficient and effective public sensitization.展开更多
This work presents a cost-effective and environment-friendly form-stabilized phase change material(PCM)and corresponding solar thermal application in the tankless solar water heater(TSWH).Coconut shell charcoal(CSC)as...This work presents a cost-effective and environment-friendly form-stabilized phase change material(PCM)and corresponding solar thermal application in the tankless solar water heater(TSWH).Coconut shell charcoal(CSC)as supporting material was modified by moderate oxidant of H_(2)O_(2)with different concentrations,and then sta-bilized stearic acid(SA)to prepare composite PCMs through vacuum impregnation.It found that CSC support causes a 15.70%improvement of SA loadage after treated by 15%H_(2)O_(2)due to coefficient enhancement by phys-ical interaction and surface modification.The modified CSC 15 support appears more super macropores which contribute to the impregnation of SA than non-modified CSC 0 support verifying from SEM and BET results.And the content of oxygen functional groups was increased after oxidation modification,also motivating SA stabiliza-tion by hydrogen bond interaction in XPS analysis.FTIR results proved there is no chemical reaction happened between SA and CSC.Moreover,the latent heat and phase transition temperature of the as-prepared SA/CSC 15 composite are 76.69 J g^(−1)and 52.52℃,respectively.All composites exhibit excellent thermal stability under a working temperature of 180℃and form stability during phase change.Thermal energy storage-release test within 70℃presents the composite has fast heat transfer efficiency than pure SA.The composite filled in TSWH system has 0.75 W m^(−1)K^(−1)thermal conductivity which is 2.88 times higher than that of pure SA(0.26 W m^(−1)K−1).Besides,the TSWH system with a flow rate of 0.004 kg s^(−1)could heat water effectively after sunset and the energy obtained from the thermal storage system within 1830 s testing times is about 0.15 kW h.In all,SA/CSC composite with good physical-thermo properties has potential in thermal energy storage application,especially in solar energy storage.展开更多
Advanced data mining methods have shown a promising capacity in building energy management.However,in the past decade,such methods are rarely applied in practice,since they highly rely on users to customize solutions ...Advanced data mining methods have shown a promising capacity in building energy management.However,in the past decade,such methods are rarely applied in practice,since they highly rely on users to customize solutions according to the characteristics of target building energy systems.Hence,the major barrier is that the practical applications of such methods remain laborious.It is necessary to enable computers to have the human-like ability to solve data mining tasks.Generative pre-trained transformers(GPT)might be capable of addressing this issue,as some GPT models such as GPT-3.5 and GPT-4 have shown powerful abilities on interaction with humans,code generation,and inference with common sense and domain knowledge.This study explores the potential of the most advanced GPT model(GPT-4)in three data mining scenarios of building energy management,i.e.,energy load prediction,fault diagnosis,and anomaly detection.A performance evaluation framework is proposed to verify the capabilities of GPT-4 on generating energy load prediction codes,diagnosing device faults,and detecting abnormal system operation patterns.It is demonstrated that GPT-4 can automatically solve most of the data mining tasks in this domain,which overcomes the barrier of practical applications of data mining methods in this domain.In the exploration of GPT-4,its advantages and limitations are also discussed comprehensively for revealing future research directions in this domain.展开更多
The Trombe wall is a passive indirect heating system which should be used in Cusco,Peru to improve thermal conditions against the typical frosts and low temperatures during winter in the high Andean regions.Due to thi...The Trombe wall is a passive indirect heating system which should be used in Cusco,Peru to improve thermal conditions against the typical frosts and low temperatures during winter in the high Andean regions.Due to this problem,the use of a modified Trombe wall with insertion of porous medium is proposed to improve thermal comfort in flat buildings in Cusco.This research aims to analyse and compare the performance of dwellings without Trombe wall,with traditional Trombe wall,and with Trombe wall with glass and plastic pellets insertion in thermal comfort improvement.Autodesk■CFD was used to simulate and analyse the system.The simulation was performed with three prototype flats(55 m^(2),75 m^(2) and 95 m^(2))for six months of the year.From the results obtained,the level of thermal comfort in the traditional scenarios is low with an average PMV of-1.86,in the scenarios with Trombe wall is good and in the scenarios with Trombe wall with insertion of porous medium is slightly better than the previous one,reaching an average PMV of+0.10 and a temperature of 21.90℃.The study carried out is important because it represents an efficient eco-sustainable heating alternative that improves the thermal comfort sensation in houses during the coldest months of the year.展开更多
Due to the majority of time people spent indoors,indoor air quality is not only critical to people’s health,comfort,but can also significantly influence occupants perception on indoor environment.Air quality is close...Due to the majority of time people spent indoors,indoor air quality is not only critical to people’s health,comfort,but can also significantly influence occupants perception on indoor environment.Air quality is closely related to many factors including thermal parameters,pollutant concentrations,and ventilation performance.However,the current building indoor air quality evaluation method is based the objective measurement of indoor parameters,without considering occupants’subjective perception.This paper is aimed at summarizing a profound review on the PAQ evaluation method.Comparisons among various PAQ evaluating methods with advantages,similarities and differences were conducted.Analysis of literatures about indoor air quality in Chinese residential buildings field is also summarized,and discussion on the subjective influence of temperature and relative humidity,venti-lation performance,volatile organic compounds(VOCs)concentration,and particulate matters on perceived air quality is carried out.展开更多
With the depletion of fossil fuel and increasing environmental concerns,the modernized era of technology is urgently in need for sustainable and eco-friendly materials.The industrial sector certainly possesses enough ...With the depletion of fossil fuel and increasing environmental concerns,the modernized era of technology is urgently in need for sustainable and eco-friendly materials.The industrial sector certainly possesses enough resources for the production of available cost-effective,renewable,reusable,and sustainable raw materials.Ul-tralight,eco-friendly and renewable cellulosic aerogels are one of the most accentuated materials in the polymer research field due to their highly abundant and inexpensive raw material,biocompatibility,high specific surface area and other feasible properties.This review summarizes the recent progress in cellulosic aerogels,their main processing route,including a detailed description of versatile new solvents along with some essential properties of cellulosic aerogels and illustrate how their variety of chemical functionalities can be adjusted for applications in the fields of thermal insulation,fire retardant,antibacterial,CO 2 capture and energy storage systems.A de-tailed morphological analysis has been elaborated and effect of processing route,solvent medium and drying procedure on the morphology of cellulosic aerogels is also decribed.Finally,we propose some suggestions to the functionalization such as silanized cellulosic aerogels and their applications in antibacterial activity yet they are still in progress and need further study for future research.展开更多
With the existence of several conventional and advanced building thermal energy demand forecast models to improve the energy efficiency of buildings,it is hard to find an appropriate,convenient,and efficient model.Eva...With the existence of several conventional and advanced building thermal energy demand forecast models to improve the energy efficiency of buildings,it is hard to find an appropriate,convenient,and efficient model.Evaluations based on statistical indexes(MAE,RMSE,MAPE,etc.)that characterize the accuracy of the forecasts do not help in the identification of the efficient building thermal energy demand forecast tool since they do not reflect the efforts entailed in implementation of the forecast model,i.e.,data collection to production/use phase.Hence,this work presents a Gini Index based Measurement of Alternatives and Ranking according to COmpromise Solution(GI-MARCOS),a hybrid Multi Attribute Decision Making(MADM)approach for the identification of the most efficient building energy demand forecast tool.GI-MARCOS employs(i)GI based objective weight method:assigns meaningful objective weights to the attributes in four phases(1:pre-processing,2:implementation,3:post-processing,and 4:use phase)thereby avoiding unnecessary biases in the expert’s opinion on weights and applicable to domains where there is a lack of domain expertise,and(ii)MARCOS:provides a robust and reliable ranking of alternatives in a dynamic environment.A case study with three alternatives evaluated over three to six attributes in four phases of implementation(pre-processing,implementation,post-processing and use)reveals that the use of GI-MARCOS improved the accuracy of alternatives MLR and BM by 6%and 13%,respectively.Moreover,additional validations state that(i)MLR performs best in Phase 1 and 2,while ANN performs best in Phase 3 and 4 with BM providing a mediocre performance in all four phases,(ii)sensitivity analysis:provides robust ranking with interchange of weights across phases and attributes,and(iii)rank correlation:ranks produce by GI-MARCOS has a high correlation with GRA(0.999),COPRAS(0.9786),and ARAS(0.9775).展开更多
The traditional ventilation mode of subway vehicles adopts the form that the inlets and outlets are placed on the upper part of the cabin.The air distribution formed in this mode often cause serious problems of therma...The traditional ventilation mode of subway vehicles adopts the form that the inlets and outlets are placed on the upper part of the cabin.The air distribution formed in this mode often cause serious problems of thermal comfort and energy consumption.In order to solve these problems caused by the traditional ventilation mode,a new hybrid ventilation mode was proposed.The hybrid ventilation mode uses both upper and underside air supply inlets.A method for evaluating the air distribution performance of subway air conditioning was developed.The method applies non-uniformity coefficients,maximum temperature difference,air diffusion performance index,modified energy utilization coefficient and Air short-circuit comprehensive coefficient.Air short-circuit comprehensive coefficient was a new index to evaluate the degree of air short-circuit of supply air.Based on the airflow simulation,the air distribution performance for the hybrid ventilation mode was evaluated using these indexes,and compared with the traditional ventilation mode.The results show that compared with the traditional ventilation mode,the hybrid ventilation mode has more uniform temperature distribution,better thermal comfort,higher energy utilization efficiency and lower degree of air short-circuit of supply air.展开更多
Zero-energy buildings constitute an effective means of reducing urban carbon emissions.High airtightness,a typical characteristic of zero-energy building,is closely related to the building’s air infiltration and has ...Zero-energy buildings constitute an effective means of reducing urban carbon emissions.High airtightness,a typical characteristic of zero-energy building,is closely related to the building’s air infiltration and has a signifi-cant impact on the performance of the building envelope,indoor air quality,building energy consumption,and efficient operation of air-conditioning systems.However,thus far,systematic developments in high-airtightness assurance technologies remain scarce.Most existing studies have tested the airtightness of buildings and typical building components;however,in-depth analyses into the formation of infiltration have not been reported.There-fore,for realizing zero-energy buildings,ensuring airtightness is an urgent problem that needs to be addressed.Accordingly,in this study,based on several building airtightness measurement studies,the typical air leakage paths in buildings were summarized,and the causes of typical air leakage components in buildings were further analysed by tracing construction processes.Moreover,targeted measures for airtightness in buildings were estab-lished and applied to practical cases.Lastly,the resulting improved building airtightness was measured and the results show that the airtightness of the measured ultra-low energy consumption buildings ranges from 0.13 h^(−1)to 0.57 h^(−1),with a mean value of 0.32 h^(−1).The effectiveness of the airtightness safeguard measures was verified.This study serves as a basis for the assumption of the air leakage path distribution when simulating building air infiltration and also provides a design reference for improving the construction technologies and airtightness of buildings.展开更多
The indoor thermal history of residents in the hot summer and cold winter climate zone in China have undergone a significant change in recent years,which also changes their seasonal thermal adaptations and this has fo...The indoor thermal history of residents in the hot summer and cold winter climate zone in China have undergone a significant change in recent years,which also changes their seasonal thermal adaptations and this has formed feed-back effects to the increasing usage of air conditioning units in this area.To study the seasonal variations of thermal adaptation,the thermal comfort experiments were conducted on two groups of participants.Each groups included 20 participants who had indoor history mainly with natural ventilation(NV group)and air-conditioning(AC group),respectively.The results demonstrated that the thermal sensation vote(TSV)in warm environments did not differ between AC and NV subjects in summer.However,the TSV of AC subjects were much lower than that of NV subjects in the same standard effective temperature and skin temperature in a cold environment in winter.Overall,the participants who spent most of their time in AC space in winter showed a low level of thermal adaptation with a narrower acceptable skin temperature range of 32.6-33.5℃.Thus,this study presents the basic information regarding the seasonal effects on human thermal adaptation due to different long-term indoor thermal histories.展开更多
基金This study is supported by the National Natural Science Foundation of China(Grant No.51706197).
文摘With the advent of the era of big data,buildings have become not only energy-intensive but also data-intensive.Data mining technologies have been widely utilized to release the values of massive amounts of building operation data with an aim of improving the operation performance of building energy systems.This paper aims at making a comprehensive literature review of the applications of data mining technologies in this domain.In general,data mining technologies can be classified into two categories,i.e.,supervised data mining technologies and unsupervised data mining technologies.In this field,supervised data mining technologies are usually utilized for building energy load prediction and fault detection/diagnosis.And unsupervised data mining technologies are usually utilized for building operation pattern identification and fault detection/diagnosis.Comprehensive discussions are made about the strengths and shortcomings of the data mining-based methods.Based on this review,suggestions for future researches are proposed towards effective and efficient data mining solutions for building energy systems.
基金supported by the National Natural Science Foun-dation of China(51805453,51978575,and 51975487)the Funda-mental Research Funds for the Central Universities(2682018CX14)the Project funded by China Postdoctoral Science Foundation(2019M663551).
文摘The coupling and complexity of railway train/tunnel system are further aggravated by increasing train speed,which produces a series of aerodynamics problems,such as aerodynamic drag,slipstream,pressure wave and micro pressure wave.Aerodynamic effects of tunnels will result in a significant increase in train energy consump-tion,shorten life of railway train/tunnel system,and increase maintenance cost.This paper provides a review of aerodynamics of railway train/tunnel system.Challenges in railway train/tunnel system aerodynamics and their related factors are discussed firstly.Aerodynamic performance and flow field characteristics of trains in tunnels are presented.Relationship of aerodynamic effects and parameters of railway train/tunnel system,and the control methods for reducing aerodynamic effects in tunnels are explained.A traffic safety evaluation of the train in tunnels,such as vehicle body structure,passengers’ear comfort,etc.,is introduced and analysed.Finally,future outlooks and research topics are proposed.
基金supported by the National Key R and D Program of China(2018YFC0704503)the international exchange program from Shanghai Committee of Science and Technology,China(18230722900).
文摘In the past several years,thermal comfort,especially development and application of thermal comfort model,has been a research focus of building environment.Since the 1970s,a series of thermal comfort models based on people’s thermal sensation to environment have been established,and gradually became an important part of the field of thermal comfort research.In this review,the existing thermal comfort models are summarized from various perspectives,such as models applied in different environments like sleeping environment and outdoor environment.Besides,models used for different groups people,such as elderly and different races are discussed.In the part,adaptive models are mentioned.In additions,data-driven models were reviewed.This paper introduced the advantages and disadvantages of each model.Based on the above review,future research work of thermal comfort model is proposed.
基金The authors are grateful to the fund of GEF/World Bank Assisted China Renewable Energy Scale-up Program with grant NO.A1-CS-2018-008.
文摘Renewable energy has become an important choice to solve the energy crisis and environmental problems.A sustainable development needs policies and strategies policies,which can improve energy efficiency and reduce greenhouse gas emissions.By collecting the research results released by relevant statistical departments and authoritative institutions,this paper summarizes the international energy development situation,systematically combs the energy development situation of the European Union,United States,Australia,India,Brazil.The development trend of wind,solar,biomass,geothermal,ocean,and hydrogen energy have been analyzed.In addition,this paper proposes that China should draw up its own development path of renewable energy from international development experience,and actively explore renewable energy policies and strategies adapted to different stages of development.
基金This study was supported by the Shenzhen Sustainable Development Science and Technology Project(2021N033)the National Key Research and Development Program(2016YFC0700404)the National Natural Science Foundation of China(51676145).
文摘This paper systematically describes the technical principles,evaluation indicators,system forms and research progress of air-side evaporative cooling air conditioning systems,water-side evaporative cooling air conditioning systems and freon-side evaporative cold coagulation heat air conditioning systems of Data center.In order to reduce the energy consumption of the refrigeration and air-conditioning system in the Data center,the applica-tion conditions and scenarios of the different forms of evaporative cooling air-conditioning systems should be considered comprehensively.Therefore,it is very important that the renewable energy-dry air can be used to the greatest extent.These efforts would contribute to China’s 2030"Carbon Peak"and 2060"Carbon Neutral."
文摘The energy consumption in buildings for heating,ventilation,and air-conditioning is increasing with the in-creasing demand for thermal comfort.Thermal energy storage with phase change material(PCM)has attracted growing attention for its role in achieving energy conservation in buildings with thermal comfort.This paper investigates the effect of PCM on the heat transfer rate in a building wall and the role of PCM on the indoor thermal comfort of the building.Two models of building wall fragments were developed for the experimental study.In one model,tests were conducted for different positions of the PCM layer in the building wall to identify the optimal position of the PCM layer inside the wall.In another model,tests were carried out integrating PCM,air gap,and other conventional building materials(brickbat and sand),one at a time,to investigate the role of PCM on the heat transfer rate in the building wall fragment.The results show that placing the PCM layer closer to the heat source gives a low-temperature gain of the cold water bath(indoor state)as compared with the PCM layer near the heat sink.With PCM,the temperature rise of the cold water bath(indoor state)of the building wall fragment was the lowest,and the slope of the temperature rise of the cold water bath becomes steadier with time i.e.,fewer temperature fluctuations.There was a significant time delay for the cold water bath to reach a given temperature.The heat required for a unit degree increase in the temperature of the cold water bath was higher and the peak heat flux of the wall was lower relative to the other building materials.
基金supported by the China National Key R&D Program(Grant No.2018YFC0704400)Technology Achievements Transfor-mation Fund Project from Sichuan Science and Technology Department(#2018YSZH0010).
文摘With the continuous deepening of China’s rural construction and development,people’s living conditions are improved day by day,while accompanied by energy and environment crisis issues.This paper mainly analyzes the energy consumption pattern and the indoor environment of rural households in China and discusses the energy-saving optimization strategies for improving the thermal environment of buildings.Questionnaire surveys and field surveys were conducted in three villages in Guanghan,China.The measurement results show that the annual indoor temperature range of the region in the summer is 15-31℃and the relative humidity range is 34%-96%.The average indoor temperatures in summer and winter are 28℃and 16℃respectively.The indoor thermal environment of rural buildings is usually poor and cannot meet the requirements of Chinese standards.At the same time,the architectural design and energy consumption pattern of rural households are different from those in urban areas as countryside has unique characteristics.Finally,we put forward certain energy-saving improvement measures at the end of the article.
基金supported by the National Key Research and Devel-opment Program of China(2018YFE0111200)the National Natural Science Foundation of China(52078053,51608051)+4 种基金the Science and Technology Department of Hunan(2019JJ30027,2020GK4057)the Changsha City Fund for Distinguished and Innovative Young Scholars(kq2106036)the Hunan Provincial Science and Technology Depart-ment(2020WK2012,2021JJ40584)the Education Department of Hu-nan Province(19C0073)the Chenzhou Municipal Science and Tech-nology Bureau(2021SFQ01).
文摘Trombe wall and phase change materials(PCMs)are two effective ways to regulate indoor thermal comfort.However,Trombe wall surfers from overheating in summer and PCMs suffer from low heat transfer rate caused by the limited thermal conductivity.To compensate the shortcomings of the two methods,this paper proposed a Trombe wall system integrated with PCMs.Based on a light-weight building envelope in Changsha,China,the thermal comfort of 10 kinds of Trombe wall systems with PCMs with a melting temperature of 18-28℃ were studied.Taking the integrated indoor discomfort duration(I_(D)),integrated indoor discomfort degree-hour(I_(DH)),indoor air temperature(T_(in)),PCM liquid fraction(γ)and heat flux across wall(q)as evaluation indexes,the indoor thermal comfort was assessed in hot summer and cold winter region.Results show that the Trombe wall helped PCMs complete the phase change process effectively.Trombe wall with PCM25 next to the wall inner surface possessed the lowest annual I_(D) and I_(DH),as 2877 h and 12,974℃·h,respectively.Compared with the values in a traditional building,the I_(D) and I_(DH) were reduced by 7.01% and 14.14%.In order to give full play to the heat storage and heat release of the Trombe wall with PCMs,PCMs with phase change temperature 7℃ lower than the peak ambient temperature in summer or 8℃ higher than the winter night temperature was recommended according to regional climate conditions.
文摘Various systems and technologies have been developed in recent years to fulfil the growing needs of high-performance HVAC systems with better performance of energy efficiency,thermal comfort,and occupancy health.Intensified conditioning of human occupied areas and less intensified conditioning of surrounding areas are able to effectively improve the overall satisfaction by individual control of personalized micro-environments and also,achieve maximum energy efficiency.Four main concepts have been identified chronologically through the devel-opment of personal environmental conditioning,changing the intensified conditioning area closer to the human body and enhancing conditioning efforts,namely the task ambient conditioning(TAC)system,personal envi-ronmental control system(PECS),personal comfort system(PCS),and the personal thermal management(PTM)system.This review follows a clue of the concept progress and system evaluation,summarizes important findings and feasible applications,current gaps as well as future research needs.
基金The authors gratefully acknowledge the support of the National Nat-ural Science Foundation of China(Grant no.51875332).
文摘Solar Aided Power Generation(SAPG)is the most efficient and economic ways to hybridise solar thermal energy and a fossil fuel fired regenerative Rankine cycle(RRC)power plant for power generation purpose.In such an SAPG plant,the solar thermal energy is used to displace the extraction steam by preheating the feedwater to the boiler.The displaced/saved extraction steam can,therefore,expand further in the steam turbine to generate power.The research and development of the SAPG technology started in the 1990s.This paper is trying to reviews and summarises the progress of research and development of the SAPG plant technology in last almost 30 or so years,including the technical and economic advantages of SAPG over other solar thermal power generation tech-nologies(e.g.solar alone power generation),various modelling techniques used to simulate SAPG perforamnce,impacts of SAPG plant’s configuration,size of solar field and strategies to adjust mass flow rate of extraction steam on the plant perforamnce,exergy analysis of SAPG plant and operation strategies to maximise plant’s economic returns etc.In addition,the directions for future R&D about SAPG technology have been pointed/proposed in this paper.
文摘Enhancing the energy efficiency of structures has been a staple of energy policies.The key goal is to slash elec-tricity usage in order to minimize the footprint of houses.This goal is sought by putting restrictions on the design specifications with respect to the properties of the raw materials and components as well as the exploitation of sustainable sources of energy.These facts for the basis for zero-energy building(ZEB)being established.This novel technology has faced several obstacles impeding its commercialization and future advancement.This inves-tigation therefore holistically explored and evaluated the state of zero energy building and factors impeding their commercialization.The review further proposed some suggestion in terms of technology that can be considered by the sector to augment existing technologies.Similarly,the investigation touched on the effect of occupant’s character in zero energy structures.Policies in terms of government subsidies and tax rebates were recommended to encourage more investors into the sector.Finally,the perception of zero energy building being more expensive compared to the traditional structures can equally be curbed via efficient and effective public sensitization.
基金This work was supported by the National Natural Science Founda-tion of China(51874047,51504041)the Training Program for Excel-lent Young Innovators of Changsha(kq1802007)+2 种基金the Fund for Univer-sity Young Core Instructors of Hunan Provincethe Outstanding Youth Project of Hunan Provincial Department of Education(18B148)and the Hunan Province 2011 Collaborative Innovation Center of Clean Energy and Smart Grid.
文摘This work presents a cost-effective and environment-friendly form-stabilized phase change material(PCM)and corresponding solar thermal application in the tankless solar water heater(TSWH).Coconut shell charcoal(CSC)as supporting material was modified by moderate oxidant of H_(2)O_(2)with different concentrations,and then sta-bilized stearic acid(SA)to prepare composite PCMs through vacuum impregnation.It found that CSC support causes a 15.70%improvement of SA loadage after treated by 15%H_(2)O_(2)due to coefficient enhancement by phys-ical interaction and surface modification.The modified CSC 15 support appears more super macropores which contribute to the impregnation of SA than non-modified CSC 0 support verifying from SEM and BET results.And the content of oxygen functional groups was increased after oxidation modification,also motivating SA stabiliza-tion by hydrogen bond interaction in XPS analysis.FTIR results proved there is no chemical reaction happened between SA and CSC.Moreover,the latent heat and phase transition temperature of the as-prepared SA/CSC 15 composite are 76.69 J g^(−1)and 52.52℃,respectively.All composites exhibit excellent thermal stability under a working temperature of 180℃and form stability during phase change.Thermal energy storage-release test within 70℃presents the composite has fast heat transfer efficiency than pure SA.The composite filled in TSWH system has 0.75 W m^(−1)K^(−1)thermal conductivity which is 2.88 times higher than that of pure SA(0.26 W m^(−1)K−1).Besides,the TSWH system with a flow rate of 0.004 kg s^(−1)could heat water effectively after sunset and the energy obtained from the thermal storage system within 1830 s testing times is about 0.15 kW h.In all,SA/CSC composite with good physical-thermo properties has potential in thermal energy storage application,especially in solar energy storage.
文摘Advanced data mining methods have shown a promising capacity in building energy management.However,in the past decade,such methods are rarely applied in practice,since they highly rely on users to customize solutions according to the characteristics of target building energy systems.Hence,the major barrier is that the practical applications of such methods remain laborious.It is necessary to enable computers to have the human-like ability to solve data mining tasks.Generative pre-trained transformers(GPT)might be capable of addressing this issue,as some GPT models such as GPT-3.5 and GPT-4 have shown powerful abilities on interaction with humans,code generation,and inference with common sense and domain knowledge.This study explores the potential of the most advanced GPT model(GPT-4)in three data mining scenarios of building energy management,i.e.,energy load prediction,fault diagnosis,and anomaly detection.A performance evaluation framework is proposed to verify the capabilities of GPT-4 on generating energy load prediction codes,diagnosing device faults,and detecting abnormal system operation patterns.It is demonstrated that GPT-4 can automatically solve most of the data mining tasks in this domain,which overcomes the barrier of practical applications of data mining methods in this domain.In the exploration of GPT-4,its advantages and limitations are also discussed comprehensively for revealing future research directions in this domain.
文摘The Trombe wall is a passive indirect heating system which should be used in Cusco,Peru to improve thermal conditions against the typical frosts and low temperatures during winter in the high Andean regions.Due to this problem,the use of a modified Trombe wall with insertion of porous medium is proposed to improve thermal comfort in flat buildings in Cusco.This research aims to analyse and compare the performance of dwellings without Trombe wall,with traditional Trombe wall,and with Trombe wall with glass and plastic pellets insertion in thermal comfort improvement.Autodesk■CFD was used to simulate and analyse the system.The simulation was performed with three prototype flats(55 m^(2),75 m^(2) and 95 m^(2))for six months of the year.From the results obtained,the level of thermal comfort in the traditional scenarios is low with an average PMV of-1.86,in the scenarios with Trombe wall is good and in the scenarios with Trombe wall with insertion of porous medium is slightly better than the previous one,reaching an average PMV of+0.10 and a temperature of 21.90℃.The study carried out is important because it represents an efficient eco-sustainable heating alternative that improves the thermal comfort sensation in houses during the coldest months of the year.
文摘Due to the majority of time people spent indoors,indoor air quality is not only critical to people’s health,comfort,but can also significantly influence occupants perception on indoor environment.Air quality is closely related to many factors including thermal parameters,pollutant concentrations,and ventilation performance.However,the current building indoor air quality evaluation method is based the objective measurement of indoor parameters,without considering occupants’subjective perception.This paper is aimed at summarizing a profound review on the PAQ evaluation method.Comparisons among various PAQ evaluating methods with advantages,similarities and differences were conducted.Analysis of literatures about indoor air quality in Chinese residential buildings field is also summarized,and discussion on the subjective influence of temperature and relative humidity,venti-lation performance,volatile organic compounds(VOCs)concentration,and particulate matters on perceived air quality is carried out.
基金We acknowledge the financial support from National Natural Sci-ence Foundation of China(NSFC,Grant No.51303151)Sichuan Province Youth Science and Technology Innovation Team(Grant No.2016TD0026)Sichuan Province Science and Engineering Project(Grant No.2018HH0087).
文摘With the depletion of fossil fuel and increasing environmental concerns,the modernized era of technology is urgently in need for sustainable and eco-friendly materials.The industrial sector certainly possesses enough resources for the production of available cost-effective,renewable,reusable,and sustainable raw materials.Ul-tralight,eco-friendly and renewable cellulosic aerogels are one of the most accentuated materials in the polymer research field due to their highly abundant and inexpensive raw material,biocompatibility,high specific surface area and other feasible properties.This review summarizes the recent progress in cellulosic aerogels,their main processing route,including a detailed description of versatile new solvents along with some essential properties of cellulosic aerogels and illustrate how their variety of chemical functionalities can be adjusted for applications in the fields of thermal insulation,fire retardant,antibacterial,CO 2 capture and energy storage systems.A de-tailed morphological analysis has been elaborated and effect of processing route,solvent medium and drying procedure on the morphology of cellulosic aerogels is also decribed.Finally,we propose some suggestions to the functionalization such as silanized cellulosic aerogels and their applications in antibacterial activity yet they are still in progress and need further study for future research.
基金supported by The Indian Institute of Technology-Bombay(Institute Postdoctoral Fellowship-AO/Admin-1/Rect/33/2019).
文摘With the existence of several conventional and advanced building thermal energy demand forecast models to improve the energy efficiency of buildings,it is hard to find an appropriate,convenient,and efficient model.Evaluations based on statistical indexes(MAE,RMSE,MAPE,etc.)that characterize the accuracy of the forecasts do not help in the identification of the efficient building thermal energy demand forecast tool since they do not reflect the efforts entailed in implementation of the forecast model,i.e.,data collection to production/use phase.Hence,this work presents a Gini Index based Measurement of Alternatives and Ranking according to COmpromise Solution(GI-MARCOS),a hybrid Multi Attribute Decision Making(MADM)approach for the identification of the most efficient building energy demand forecast tool.GI-MARCOS employs(i)GI based objective weight method:assigns meaningful objective weights to the attributes in four phases(1:pre-processing,2:implementation,3:post-processing,and 4:use phase)thereby avoiding unnecessary biases in the expert’s opinion on weights and applicable to domains where there is a lack of domain expertise,and(ii)MARCOS:provides a robust and reliable ranking of alternatives in a dynamic environment.A case study with three alternatives evaluated over three to six attributes in four phases of implementation(pre-processing,implementation,post-processing and use)reveals that the use of GI-MARCOS improved the accuracy of alternatives MLR and BM by 6%and 13%,respectively.Moreover,additional validations state that(i)MLR performs best in Phase 1 and 2,while ANN performs best in Phase 3 and 4 with BM providing a mediocre performance in all four phases,(ii)sensitivity analysis:provides robust ranking with interchange of weights across phases and attributes,and(iii)rank correlation:ranks produce by GI-MARCOS has a high correlation with GRA(0.999),COPRAS(0.9786),and ARAS(0.9775).
文摘The traditional ventilation mode of subway vehicles adopts the form that the inlets and outlets are placed on the upper part of the cabin.The air distribution formed in this mode often cause serious problems of thermal comfort and energy consumption.In order to solve these problems caused by the traditional ventilation mode,a new hybrid ventilation mode was proposed.The hybrid ventilation mode uses both upper and underside air supply inlets.A method for evaluating the air distribution performance of subway air conditioning was developed.The method applies non-uniformity coefficients,maximum temperature difference,air diffusion performance index,modified energy utilization coefficient and Air short-circuit comprehensive coefficient.Air short-circuit comprehensive coefficient was a new index to evaluate the degree of air short-circuit of supply air.Based on the airflow simulation,the air distribution performance for the hybrid ventilation mode was evaluated using these indexes,and compared with the traditional ventilation mode.The results show that compared with the traditional ventilation mode,the hybrid ventilation mode has more uniform temperature distribution,better thermal comfort,higher energy utilization efficiency and lower degree of air short-circuit of supply air.
基金the Natural Science Foundation of Shandong Province Youth Project(Grant no.ZR2020QE224).
文摘Zero-energy buildings constitute an effective means of reducing urban carbon emissions.High airtightness,a typical characteristic of zero-energy building,is closely related to the building’s air infiltration and has a signifi-cant impact on the performance of the building envelope,indoor air quality,building energy consumption,and efficient operation of air-conditioning systems.However,thus far,systematic developments in high-airtightness assurance technologies remain scarce.Most existing studies have tested the airtightness of buildings and typical building components;however,in-depth analyses into the formation of infiltration have not been reported.There-fore,for realizing zero-energy buildings,ensuring airtightness is an urgent problem that needs to be addressed.Accordingly,in this study,based on several building airtightness measurement studies,the typical air leakage paths in buildings were summarized,and the causes of typical air leakage components in buildings were further analysed by tracing construction processes.Moreover,targeted measures for airtightness in buildings were estab-lished and applied to practical cases.Lastly,the resulting improved building airtightness was measured and the results show that the airtightness of the measured ultra-low energy consumption buildings ranges from 0.13 h^(−1)to 0.57 h^(−1),with a mean value of 0.32 h^(−1).The effectiveness of the airtightness safeguard measures was verified.This study serves as a basis for the assumption of the air leakage path distribution when simulating building air infiltration and also provides a design reference for improving the construction technologies and airtightness of buildings.
基金supported by the High-end Foreign Experts Recruitment Plan of China(Grant No.G2021165006L),and the 111 Project(Grant No.B13041).
文摘The indoor thermal history of residents in the hot summer and cold winter climate zone in China have undergone a significant change in recent years,which also changes their seasonal thermal adaptations and this has formed feed-back effects to the increasing usage of air conditioning units in this area.To study the seasonal variations of thermal adaptation,the thermal comfort experiments were conducted on two groups of participants.Each groups included 20 participants who had indoor history mainly with natural ventilation(NV group)and air-conditioning(AC group),respectively.The results demonstrated that the thermal sensation vote(TSV)in warm environments did not differ between AC and NV subjects in summer.However,the TSV of AC subjects were much lower than that of NV subjects in the same standard effective temperature and skin temperature in a cold environment in winter.Overall,the participants who spent most of their time in AC space in winter showed a low level of thermal adaptation with a narrower acceptable skin temperature range of 32.6-33.5℃.Thus,this study presents the basic information regarding the seasonal effects on human thermal adaptation due to different long-term indoor thermal histories.
