Pressure has been introduced into power systems owing to the intermittent and uncertain nature of renewable energy.As a result,energy resource aggregators are emerging in the electricity market to realize sustainable ...Pressure has been introduced into power systems owing to the intermittent and uncertain nature of renewable energy.As a result,energy resource aggregators are emerging in the electricity market to realize sustainable and economic advantages through distributed generation,energy storage,and demand response resources.However,resource aggregators face the challenge of dealing with the uncertainty of renewable energy generation and setting appropriate incentives to exploit substantial energy flexibility in the building sector.In this study,a risk-aware optimal dispatch strategy that integrates probabilistic renewable energy prediction and bi-level building flexibility engagements is proposed.A natural gradient boosting algorithm(NGBoost),which requires no prior knowledge of uncertain variables,was adopted to develop a probabilistic photovoltaic(PV)forecasting model.The lack of suitable flexibility incentives is addressed by a novel interactive flexibility engagement scheme that can take into account building users'willingness and optimize the building flexibility provision.The chance-constrained programming method was applied to manage the supply-demand balance of the resource aggregator and ensure risk-aware decision-making in power dispatch.The case study results show the strong economic and environmental performance of the proposed strategy.The proposed strategy leads to a win-win situation in which profit increases through a load reduction of 13% and a carbon emission reduction of 3% is achieved for different stakeholders,which also shows a trade-off between the economic benefits and the risk of supply shortage.展开更多
Effective wildland fire management requires real-time access to comprehensive and distilled information from different data sources.The Digital Twin technology becomes a promising tool in optimizing the processes of w...Effective wildland fire management requires real-time access to comprehensive and distilled information from different data sources.The Digital Twin technology becomes a promising tool in optimizing the processes of wildfire pre-vention,monitoring,disaster response,and post-fire recovery.This review examines the potential utility of Digital Twin in wildfire management and aims to inspire further exploration and experimentation by researchers and practitioners in the fields of environment,forestry,fire ecology,and firefighting services.By creating virtual replicas of wildfire in the physical world,a Digital Twin platform facilitates data integration from multiple sources,such as remote sensing,weather forecast-ing,and ground-based sensors,providing a holistic view of emergency response and decision-making.Furthermore,Digital Twin can support simulation-based training and scenario testing for prescribed fire planning and firefighting to improve preparedness and response to evacuation and rescue.Successful applications of Digital Twin in wildfire management require horizontal collaboration among researchers,practitioners,and stakeholders,as well as enhanced resource sharing and data exchange.This review seeks a deeper understanding of future wildland fire management from a technological perspective and inspiration of future research and implementation.Further research should focus on refining and validating Digital Twin models and the integration into existing fire management operations,and then demonstrating them in real wildland fires.展开更多
Natural gas is widely regarded as an efficient,relatively clean,and economically viable energy source.Its safe operation and continuous supply through pipeline infrastructure has led to its prominence in the energy se...Natural gas is widely regarded as an efficient,relatively clean,and economically viable energy source.Its safe operation and continuous supply through pipeline infrastructure has led to its prominence in the energy sector.Methanol plays an important role in the natural gas industry,typically serving as a solvent or hydrate inhibitor.Therefore,the accurate estimation of thermodynamic properties for methane/methanol binary is extremely important to optimise the operating parameter,maximise the dehydration effect,and reduce the cost.As the Helmholtz energy equation of state is expected to offer high accuracy in predicting the vapour-liquid equilibrium of methane/methanol binary,four reducing parameters were derived based on collected experimental data.Additionally,the sensitivities of various reducing parameter combinations were simultaneously investigated.The results demonstrated a strong agreement between predicted fractions and experimental data,with the UMADs(uncertainty-weighted mean absolute deviation)of 3.484 and 0.665 for liquid and vapour phases,respectively.Meanwhile,it is deemed“very likely”,“likely”,and“unlikely”to achieve acceptable prediction for 3-parameter optimisation,2-parameter optimisation and,1-parameter optimisation,respectively.展开更多
Vacuum glazing is highly regarded for its ability to transmit light while providing heat preservation,sound insulation,lightweight characteristics,and resistance to condensation.Scholars have made significant strides ...Vacuum glazing is highly regarded for its ability to transmit light while providing heat preservation,sound insulation,lightweight characteristics,and resistance to condensation.Scholars have made significant strides in the study of vacuum glazing through their notable efforts.This study systematically reviewed vacuum glazing and its composite structures,including material selection,fabrication techniques,research methods,and performance evaluation.This review initially presented fundamental techniques for preparing vacuum glazing,with a focus on edge seal and support pillar arrangements,and introduced common composite structures such as hybrid and tinted vacuum glazing.Furthermore,this review summarized the analytical,numerical,and experimental methodologies used to assess the thermal performance of vacuum glazing.This study also outlined heat transfer coefficients associated with various vacuum glazing structures,investigated the influence of different parameters on their heat transfer coefficients,and evaluated their potential for energy conservation across diverse climatic regions.Finally,the research delineated future trends in the advancement of vacuum glazing to provide guidance for both theoretical studies and practical applications in industry.This research serves as a valuable resource for both theoretical exploration and practical integration of vacuum glazing,facilitating its improvement and optimization to advance sustainable low-carbon building practices.展开更多
Shrublands and grasslands,which constitute approximately 70%of Australia’s vegetation,play a critical role in global wildfire-prone regions.To advance the understanding of grass fire spread,a three-dimensional,physic...Shrublands and grasslands,which constitute approximately 70%of Australia’s vegetation,play a critical role in global wildfire-prone regions.To advance the understanding of grass fire spread,a three-dimensional,physicsbased fire model provides valuable insights into fire dynamics.However,such models are computationally intensive and time-consuming.To address these challenges,we constructed an extensive numerical database comprising 64,000 high-fidelity wildfire simulation cases and implemented a Long Short-Term Memory neural network architecture.The model demonstrates strong predictive performance,achieving a coefficient of determination(R2)of 0.96 on training data,indicating excellent agreement with the physics-based simulation outputs.By utilizing coordinates from five reference points to predict fire front movement,this approach offers a novel method for analysing fire dynamics in homogeneous fuel beds with an average deviation of less than 2.5%.Combining the strengths of physics-based modelling and deep learning,our research enhances fire spread prediction accuracy of over 95%while significantly reducing computational demands.Future efforts will focus on refining the model,expanding the dataset,and incorporating additional variables to improve predictive capabilities and operational applicability.展开更多
An active pipe-embedded building envelope, which is an external wall or roof with pipes embedded inside, was presented. This structure may utilize the circulating water in the pipe to transfer heat or coolth inside di...An active pipe-embedded building envelope, which is an external wall or roof with pipes embedded inside, was presented. This structure may utilize the circulating water in the pipe to transfer heat or coolth inside directly. This kind of structure is named ＂active pipe-embedded building envelope＂ due to dealing with the thermal energy actively inside the structure mass by circulating water. This structure not only deals with thermal energy before the external disturbance becomes cooling/heating load by using the circulating water, but also may use low-grade energy sources such as evaporative cooling, solar energy, and geothermal energy. In the meantime, this structure can also improve the indoor thermal comfort by tempering the internal wall surface temperature variation due to the thermal removal in the mass. This work further presents the thermal performance of this structure under a typical hot summer weather condition by comparing it with that of the conventional external wall/roof with numerical simulation. The results show that this pipe-embedded structure may reduce the external heat transfer significantly and reduce the internal wall surface temperature for improving thermal comfort. This work also presents the effects of the water temperature and the pipe spacing on the heat transfer of this structure. The internal surface heat transfer may reduce by about 2.6 W/mE when the water temperature reduces by 1℃ as far as a brick wall with pipes embedded inside is concerned. When the pipe spacing reduces by 50 mm, the internal wall surface heat flux can also reduce by about 2.3 W/m2.展开更多
The fluorescence staining method and scanning electron microscopy （SEM） were used to study the effect of ozone （O3） inactivating Cryptosporidium in water and cell ultrastructures variation to shed light on the mec...The fluorescence staining method and scanning electron microscopy （SEM） were used to study the effect of ozone （O3） inactivating Cryptosporidium in water and cell ultrastructures variation to shed light on the mechanism of inactivation preliminarily. Results indicated that O3 had a stronger inactivating capability. When the concentration of O3 was above 3.0 mg/L and the contact time was up to 7 min, a significant inactivating effect could be achieved. The turbidity on inactivation effects was also found to be statistically significant in artificial water. With increases in turbidity, the inactivating effect decreased. Inactivation rate improved with a temperature increase from 5 to 25℃, but decreased beyond this. The inactivating capability of O3 was found to be stronger under acidic than that under alkalic conditions. When the concentration of organic matter in the reaction system was increased, the competition between Cryptosporidium and organics with O3 probably took place, thereby reducing the inactivation rate. In addition, the cellular morphology of Cryptosporidium varied with different contact times. At zero contact time, cells were rotundity and sphericity, at 60 sec they became folded, underwent emboly, and burst at 480 sec, the cell membrane of Cryptosporidium shrinked and collapsed completely.展开更多
Organ-on-a-chip systems have been increasingly recognized as attractive platforms to assess toxicity and to develop new therapeutic agents.However,current organ-on-a-chip platforms are limited by a“single pot”design...Organ-on-a-chip systems have been increasingly recognized as attractive platforms to assess toxicity and to develop new therapeutic agents.However,current organ-on-a-chip platforms are limited by a“single pot”design,which inevitably requires holistic analysis and limits parallel processing.Here,we developed a digital organ-on-a-chip by combining a microwell array with cellular microspheres,which significantly increased the parallelism over traditional organ-on-a-chip for drug development.Up to 127 uniform liver cancer microspheres in this digital organ-on-a-chip format served as individual analytical units,allowing for analysis with high consistency and quick response.Our platform displayed evident anti-cancer efficacy at a concentration of 10μM for sorafenib,and had greater alignment than the“single pot”organ-on-a-chip with a previous in vivo study.In addition,this digital organ-on-a-chip demonstrated the treatment efficacy of natural killer cell-derived extracellular vesicles for liver cancer at 50μg/mL.The successful development of this digital organ-on-a-chip platform provides high-parallelism and a low-variability analytical tool for toxicity assessment and the exploration of new anticancer modalities,thereby accelerating the joint endeavor to combat cancer.展开更多
A comparative optimal design of fluid-saturated prismatic cellular metal honeycombs （PCMHs） having different cell shapes is presented for thermal management applications. Based on the periodic topology of each PCMH,...A comparative optimal design of fluid-saturated prismatic cellular metal honeycombs （PCMHs） having different cell shapes is presented for thermal management applications. Based on the periodic topology of each PCMH, a unit cell （UC） for thermal transport analysis was selected to calculate its effective thermal conductivity. Without introducing any empirical coefficient, we modified and extended the analytical model of parallel-series thermal-electric network to a wider porosity range （0.7 ~ 0.98） by considering the effects of two-dimensional local heat conduction in solid ligaments inside each UC. Good agreement was achieved between analytical predictions and numerical simulations based on the method of finite volume. The concept of ligament heat conduction efficiency （LTCE） was proposed to physically explain the mechanisms underlying the effects of ligament configuration on effective thermal conductivity （ETC）. Based upon the proposed theory, a construct strategy was developed for designing the ETC by altering the equivalent interaction angle with the direction of heat flow： relatively small average interaction angle for thermal conduction and relatively large one for thermal insulation.展开更多
The undisturbed ground temperatures are important for design of the ground heat exchangers in ground source heat pump （GSHP） systems. In this paper, the undisturbed ground temperatures measured in two different me...The undisturbed ground temperatures are important for design of the ground heat exchangers in ground source heat pump （GSHP） systems. In this paper, the undisturbed ground temperatures measured in two different methods are presented. The investigation was carried out in two cases. The temperature measured with the direct method is assumed to give the correct undisturbed ground temperature profile. The temperature measured with indirect method overestimates the undisturbed ground temperature by 2.1℃ and 1.7~C. This difference is mainly caused by the circulation pump and ambient air to the fluid. Therefore, the results that are decreased about 2℃ as compared with the indirect measured are recommended to estimate the undisturbed ground temperature in situ measuring. A smaller pump or deeper borehole or mild weather would result in a more correct temperature. Because the undisturbed ground temperature is affected by many factors. Whether or not these conclusions are correct to other areas, this would need further investigation.展开更多
Tropical peat comprises decomposed dead plant material and acts like a sponge to absorb water,making it fully saturated.However,drought periods dry it readily and increases its vulnerability to fire.Peat fires emit gr...Tropical peat comprises decomposed dead plant material and acts like a sponge to absorb water,making it fully saturated.However,drought periods dry it readily and increases its vulnerability to fire.Peat fires emit greenhouse gases and particles contributing to haze,and prevention by constructing fire-break canals to reduce fire spread into forest reserves is crucial.This paper aims to determine peat physical and chemical properties near a fire-break canal at different fire frequency areas.Peat sampling was conducted at two forest reserves in Malaysia which represent low fire frequency and high fire frequency areas.The results show that peat properties were not affected by the construction of a fire-break canal,however lignin and cellulose content increased significantly from the distance of the canal in both areas.The study concluded that fire frequency did not significantly influence peat properties except for porosity.The higher fibre content in the high frequency area did not influence moisture content nor the ability to regain moisture.Thus,fire frequency might contribute differently to changes in physical and chemical properties,hence management efforts to construct fire-break canals and restoration efforts should protect peatlands from further degradation.These findings will benefit future management and planning for forest reserves.展开更多
Given the complexities of reinforced soil materials’constitutive relationships,this paper compares reinforced soil composite materials to a sliding structure between steel bars and soil and proposes a reinforced soil...Given the complexities of reinforced soil materials’constitutive relationships,this paper compares reinforced soil composite materials to a sliding structure between steel bars and soil and proposes a reinforced soil constitutive model that takes this sliding into account.A finite element dynamic time history calculation software for composite response analysis was created using the Fortran programming language,and time history analysis was performed on reinforced soil retaining walls and gravity retaining walls.The vibration time histories of reinforced soil retaining walls and gravity retaining walls were computed,and the dynamic reactions of the two types of retaining walls to vibration were compared and studied.The dynamic performance of reinforced earth retaining walls was evaluated.展开更多
During coal mining, water resources may be polluted by acid mine drainage (AMD) if appropriate measures are not taken. AMD releases metals to the environment, which can be harmful to aquatic species and reduce biodive...During coal mining, water resources may be polluted by acid mine drainage (AMD) if appropriate measures are not taken. AMD releases metals to the environment, which can be harmful to aquatic species and reduce biodiversity. There is a great deal of information available in the literature on the generation and treatment of AMD and this paper tries to summarize some of them in order to facilitate the choice of the most appropriate method for AMD treatment at a specific mining site. The objective of this study was to identify and describe different methods of treating polluted water from coal mining, and to discuss the choice of suitable methods at specific mining sites. Both active and passive methods of AMD treatment are discussed in order to provide a general picture of the measures that have been taken around the world by coal mining companies. From this study, we were able to conclude that in order to choose the appropriate method for a specific mining site it is necessary to analyze the chemistry of the acid water and the flow rate from that site. The cost, implementability and effectiveness of the method should also be considered. Minimizing the amount of drainage water generated is naturally the first choice of management strategy and the containment of the AMD is the second choice. The third alternative is the treatment of the wastewater.展开更多
Freshwater lakes globally are witnessing an escalation in the frequency and intensity of cyanobacterial harmful blooms.However,underlying factors influencing the succession or coexistence of cyanobacteria,especially f...Freshwater lakes globally are witnessing an escalation in the frequency and intensity of cyanobacterial harmful blooms.However,underlying factors influencing the succession or coexistence of cyanobacteria,especially filamentous ones,remain poorly understood.Lake Honghu,a Ramsar Wetland of International Importance with degrading aquatic ecological quality,served as a case study to elucidate the intricate relationship between environmental changes and cyanobacterial dynamics.Our analysis revealed a significant increase in the dominance of filamentous cyanobacteria,marked by high spatiotemporal variability in community structure.This dominance of filamentous diazotrophic cyanobacteria is attributed to a decrease in the ratio of dissolved inorganic nitrogen to total phosphorus and their capacity to utilize organic phosphorus in phosphorus-deficient conditions.Species-specific density variations were linked to diverse environmental factors,with total nitrogen or total phosphorus concentration remaining as a crucial factor influencing dominant cyanobacterial density fluctuations.The dominance of low-temperature-tolerant Aphanizomenon and Pseudanabaena was evident in spring and winter,whereas Dolichospermum and Cylindrospermopsis,which prefer higher temperatures,thrived in summer and autumn.Additionally,non-algal turbidity and heterogeneity can potentially alter the competitive outcome among filamentous cyanobacteria or foster coexistence under conditions of elevated temperatures and nutrient limitation.This study predicts that filamentous cyanobacteria may spread and persist in lakes spanning a wide trophic range.Current findings enhance our comprehen-sion of the dynamic responses exhibited by filamentous bloom-forming cyanobacteria in the face of environmental changes within shallow eutrophic lakes and provide valuable insights for lake managers involved in the remediation of degraded shallow lakes.展开更多
Interfacial solar evaporation,which captures solar energy and localizes the absorbed heat for water evaporation,is considered a promising technology for seawater desalination and solar energy conversion.However,it is ...Interfacial solar evaporation,which captures solar energy and localizes the absorbed heat for water evaporation,is considered a promising technology for seawater desalination and solar energy conversion.However,it is currently limited by its low photothermal conversion efficiency,salt accumulation,and poor reliability.Herein,inspired by human intestinal villi structure,we design and fabricate a novel intestinal villi-like nitrogen-doped carbon nanotubes solar steam generator(N-CNTs SSG)consisting of three-dimensional(3D)hierarchical carbon nanotube matrices for ultrahigh solar evaporation efficiency.The 3D matrices with radial direction nitrogen-doped carbon nanotube clusters achieve ultrahigh surface area,photothermal efficiency,and hydrophilicity,which significantly intensifies the whole interfacial solar evaporation process.The new solar evaporation efficiency reaches as high as 96.8%.Furthermore,our ab initio molecular dynamics simulation reveals that N-doped carbon nanotubes exhibit a greater number of electronic states in close proximity to the Fermi level when compared to pristine carbon nanotubes.The outstanding absorptivity in the full solar spectrum and high solar altitude angles of the 3D hierarchical carbon nanotube matrices offer great potential to enable ultrahigh photothermal conversion under all-day and all-season circumstances.展开更多
Development of individual building in existing district is common in high-density cities due to the limited space.Such development affects the local microclimate naturally,but the interaction is ignored in current bui...Development of individual building in existing district is common in high-density cities due to the limited space.Such development affects the local microclimate naturally,but the interaction is ignored in current building design practices.In this study,a comprehensive and systematic analysis is conducted to investigate the mutual impacts between new individual building design and local microclimate considering the interaction,and to identify the major influential building parameters on both local microclimate and building energy performance in subtropical urban area.A large number of high-resolution microclimate and building simulations are performed based on advanced GIS spatial analysis techniques under different building designs for the assessment of mutual impacts.A global sensitivity analysis is conducted to identify the major influential building parameters.The results show that different building designs lead to significant variation of local wind velocity(i.e.,−0.95 to+4.51 m/s)and air temperature(i.e.,−0.60 to+1.17 K),while the local microclimate results in a change in the building energy consumption from−41.75 to 291.54 kJ/m^(2).The major influential parameters on both pedestrian thermal discomfort and building energy performance are building height and overall heat transfer coefficient of the building envelope.This study provides valuable references for new building or rebuilding design in order to facilitate carbon neutrality and enhance thermal comfort in urban area.展开更多
With the rapid increase in solar photovoltaic(PV)installation capacity,the strain on grid transmission burden has intensified.A house energy management system is recognized as an effective solution to mitigate this gr...With the rapid increase in solar photovoltaic(PV)installation capacity,the strain on grid transmission burden has intensified.A house energy management system is recognized as an effective solution to mitigate this grid burden.However,existing research has not fully explored the potential of battery utilization and the forecasting of uncertainties.In this paper,a novel multi-objective optimization framework based on the genetic algorithm-based method for the house energy management system is proposed,to enhance renewable self-consumption,improve on-site renewable self-sufficiency,and optimize economic benefits for users.The framework integrates an artificial neural network for predictions of meteorological data and user load at a 5-minute temporal resolution,enabling the simulation and optimization of the PV-battery-flexible load system.Emphasizing deferrable loads,constant-temperature control loads,and batteries,the proposed framework devises optimal strategies for distributed PV battery systems in residential.It harnesses load flexibility and battery storage capabilities while incorporating comfort assessment metrics.This approach significantly improves the system’s economic and technical performance metrics,with system self-consumption rate,self-sufficiency rate,and cost reduction ratio improved by 13.5%,11.3%,and 6.2%,respectively,compared to the basic strategy.Additionally,the optimization of the air conditioning system enhances alignment with the photovoltaic generation,resulting in a 9.8%reduction in energy consumption and a 9.4%decrease in electricity costs,while maintaining user comfort at an acceptable level.The proposed framework promotes the practical application of renewable management systems,highlighting renewable energy efficient utilization,grid dependency reduction,and user economic benefit increase.展开更多
One of the challenges in construction of nearly and net ZEBs is how to truly achieve the nearly and net energy goals after building occupancy.Traditional building design standards and practices are mostly based on des...One of the challenges in construction of nearly and net ZEBs is how to truly achieve the nearly and net energy goals after building occupancy.Traditional building design standards and practices are mostly based on design performance evaluation,but practices show that many designed nearly/net ZEBs failed to achieve the energy goals after building occupancy.To facilitate the practical achievement of nearly and net ZEBs,recently most of the newly-released ZEB design standards have turned to post-occupancy performance evaluation,posing great challenges to nearly and net ZEB design.However,the detailed challenges have not be comprehensively investigated,and effective optimal design methods which can facilitate the achievement of nearly and net ZEBs under these standards are still absent.In this study,new challenges of nearly and net ZEB design under the post-occupancy performance-based design standards are fully investigated,and a risk-benefit based optimal design method is proposed to facilitate the achievement of nearly and net ZEBs under these standards.The newly-released ZEB standard in China is taken as an example to investigate the challenges and test the proposed method.Results show that nearly and net ZEBs designed using conventional design method have high risk in achieving energy goals under these standards due to high risk in satisfying the requirement regarding non-renewable primary energy consumption after building occupancy.The proposed design method is effective to facilitate achieving energy goals under these standards based on the risk that decision-makers would like to take.展开更多
The building sector is facing a challenge in achieving carbon neutrality due to climate change and urbanization.Urban building energy modeling(UBEM)is an effective method to understand the energy use of building stock...The building sector is facing a challenge in achieving carbon neutrality due to climate change and urbanization.Urban building energy modeling(UBEM)is an effective method to understand the energy use of building stocks at an urban scale and evaluate retrofit scenarios against future weather variations,supporting the implementation of carbon emission reduction policies.Currently,most studies focus on the energy performance of archetype buildings under climate change,which is hard to obtain refined results for individual buildings when scaling up to an urban area.Therefore,this study integrates future weather data with an UBEM approach to assess the impacts of climate change on the energy performance of urban areas,by taking two urban neighborhoods comprising 483 buildings in Geneva,Switzerland as case studies.In this regard,GIS datasets and Swiss building norms were collected to develop an archetype library.The building heating energy consumption was calculated by the UBEM tool—AutoBPS,which was then calibrated against annual metered data.A rapid UBEM calibration method was applied to achieve a percentage error of 2.7%.The calibrated models were then used to assess the impacts of climate change using four future weather datasets out of Shared Socioeconomic Pathways(SSP1-2.6,SSP2-4.5,SSP3-7.0,and SSP5-8.5).The results showed a decrease of 22%–31%and 21%–29%for heating energy consumption,an increase of 113%–173%and 95%–144%for cooling energy consumption in the two neighborhoods by 2050.The average annual heating intensity dropped from 81 kWh/m^(2) in the current typical climate to 57 kWh/m^(2) in the SSP5-8.5,while the cooling intensity rose from 12 kWh/m^(2) to 32 kWh/m^(2).The overall envelope system upgrade reduced the average heating and cooling energy consumption by 41.7%and 18.6%,respectively,in the SSP scenarios.The spatial and temporal distribution of energy consumption change can provide valuable information for future urban energy planning against climate change.展开更多
Temperature and humidity are two important factors that influence both indoor thermal comfort and air quality.Through varying compressor and supply fan speeds of a direct expansion(DX)air conditioning(A/C)unit,the air...Temperature and humidity are two important factors that influence both indoor thermal comfort and air quality.Through varying compressor and supply fan speeds of a direct expansion(DX)air conditioning(A/C)unit,the air temperature and humidity in the conditioned space can be regulated simultaneously.However,most existing controllers are designed to minimize the tracking errors between the system outputs with their corresponding settings as quickly as possible.The energy consumption,which is directly influenced by the compressor and supply fan speeds,is not considered in the relevant controller formulations,and thus the system may not operate with the highest possible energy efficiency.To effectively control temperature and humidity while minimizing the system energy consumption,a model predictive control(MPC)strategy was developed for a DX A/C system,and the development results are presented in this paper.A physically-based dynamic model for the DX A/C system with both sensible and latent heat transfers being considered was established and validated by experiments.To facilitate the design of MPC,the physical model was further linearized.The MPC scheme was then developed by formulating the objective function which sought to minimize the tracking errors of temperature and moisture content while saving energy consumption.Based on the results of command following and disturbance rejection tests,the proposed MPC scheme was capable of controlling temperature and humidity with adequate control accuracy and sensitivity.In comparison to linear-quadratic-Gaussian(LQG)controller,better control accuracy and lower energy consumption could be realized when using the proposed MPC strategy to simultaneously control temperature and humidity.展开更多
基金financially supported by the Collaborative Research Fund(C5018-20GF)of the Research Grant Council(RGC)of Hong Kong Special Administrative Regionthe Shenzhen Science and Technology Innovation Commission Grant(KCXST20221021111203007)。
文摘Pressure has been introduced into power systems owing to the intermittent and uncertain nature of renewable energy.As a result,energy resource aggregators are emerging in the electricity market to realize sustainable and economic advantages through distributed generation,energy storage,and demand response resources.However,resource aggregators face the challenge of dealing with the uncertainty of renewable energy generation and setting appropriate incentives to exploit substantial energy flexibility in the building sector.In this study,a risk-aware optimal dispatch strategy that integrates probabilistic renewable energy prediction and bi-level building flexibility engagements is proposed.A natural gradient boosting algorithm(NGBoost),which requires no prior knowledge of uncertain variables,was adopted to develop a probabilistic photovoltaic(PV)forecasting model.The lack of suitable flexibility incentives is addressed by a novel interactive flexibility engagement scheme that can take into account building users'willingness and optimize the building flexibility provision.The chance-constrained programming method was applied to manage the supply-demand balance of the resource aggregator and ensure risk-aware decision-making in power dispatch.The case study results show the strong economic and environmental performance of the proposed strategy.The proposed strategy leads to a win-win situation in which profit increases through a load reduction of 13% and a carbon emission reduction of 3% is achieved for different stakeholders,which also shows a trade-off between the economic benefits and the risk of supply shortage.
基金funded by the National Natural Science Foundation of China(NSFC No.52322610)Hong Kong Research Grants Council Theme-based Research Scheme(T22-505/19-N).
文摘Effective wildland fire management requires real-time access to comprehensive and distilled information from different data sources.The Digital Twin technology becomes a promising tool in optimizing the processes of wildfire pre-vention,monitoring,disaster response,and post-fire recovery.This review examines the potential utility of Digital Twin in wildfire management and aims to inspire further exploration and experimentation by researchers and practitioners in the fields of environment,forestry,fire ecology,and firefighting services.By creating virtual replicas of wildfire in the physical world,a Digital Twin platform facilitates data integration from multiple sources,such as remote sensing,weather forecast-ing,and ground-based sensors,providing a holistic view of emergency response and decision-making.Furthermore,Digital Twin can support simulation-based training and scenario testing for prescribed fire planning and firefighting to improve preparedness and response to evacuation and rescue.Successful applications of Digital Twin in wildfire management require horizontal collaboration among researchers,practitioners,and stakeholders,as well as enhanced resource sharing and data exchange.This review seeks a deeper understanding of future wildland fire management from a technological perspective and inspiration of future research and implementation.Further research should focus on refining and validating Digital Twin models and the integration into existing fire management operations,and then demonstrating them in real wildland fires.
基金supported financially by the National Natural Science Foundation of China(52202434)the National Natural Science Foundation of Ningbo(2023J275).
文摘Natural gas is widely regarded as an efficient,relatively clean,and economically viable energy source.Its safe operation and continuous supply through pipeline infrastructure has led to its prominence in the energy sector.Methanol plays an important role in the natural gas industry,typically serving as a solvent or hydrate inhibitor.Therefore,the accurate estimation of thermodynamic properties for methane/methanol binary is extremely important to optimise the operating parameter,maximise the dehydration effect,and reduce the cost.As the Helmholtz energy equation of state is expected to offer high accuracy in predicting the vapour-liquid equilibrium of methane/methanol binary,four reducing parameters were derived based on collected experimental data.Additionally,the sensitivities of various reducing parameter combinations were simultaneously investigated.The results demonstrated a strong agreement between predicted fractions and experimental data,with the UMADs(uncertainty-weighted mean absolute deviation)of 3.484 and 0.665 for liquid and vapour phases,respectively.Meanwhile,it is deemed“very likely”,“likely”,and“unlikely”to achieve acceptable prediction for 3-parameter optimisation,2-parameter optimisation and,1-parameter optimisation,respectively.
基金supported by the National Key R&D Program of China(2023YFC3806202)the National Natural Science Foundation of China(52308093)+3 种基金the Natural Science Foundation of Hunan Province(2023JJ40154)the Science and Technology Innovation Leading Talent Program of Hunan Province(2023RC1042)the Natural Science Foundation of Changsha(kq2208032)the China Postdoctoral Science Foundation(2023M741132 and 2024T170263)。
文摘Vacuum glazing is highly regarded for its ability to transmit light while providing heat preservation,sound insulation,lightweight characteristics,and resistance to condensation.Scholars have made significant strides in the study of vacuum glazing through their notable efforts.This study systematically reviewed vacuum glazing and its composite structures,including material selection,fabrication techniques,research methods,and performance evaluation.This review initially presented fundamental techniques for preparing vacuum glazing,with a focus on edge seal and support pillar arrangements,and introduced common composite structures such as hybrid and tinted vacuum glazing.Furthermore,this review summarized the analytical,numerical,and experimental methodologies used to assess the thermal performance of vacuum glazing.This study also outlined heat transfer coefficients associated with various vacuum glazing structures,investigated the influence of different parameters on their heat transfer coefficients,and evaluated their potential for energy conservation across diverse climatic regions.Finally,the research delineated future trends in the advancement of vacuum glazing to provide guidance for both theoretical studies and practical applications in industry.This research serves as a valuable resource for both theoretical exploration and practical integration of vacuum glazing,facilitating its improvement and optimization to advance sustainable low-carbon building practices.
基金funded by the National Natural Science Foundation of China(NSFC No.52322610)Hong Kong Research Grants Council Theme-based Research Scheme(T22-505/19-N)Furthermore,this research was undertaken with the assistance of computational resources from the National Computational Infrastructure(NCI Australia),an NCRISenabled capability supported by the Australian Government.
文摘Shrublands and grasslands,which constitute approximately 70%of Australia’s vegetation,play a critical role in global wildfire-prone regions.To advance the understanding of grass fire spread,a three-dimensional,physicsbased fire model provides valuable insights into fire dynamics.However,such models are computationally intensive and time-consuming.To address these challenges,we constructed an extensive numerical database comprising 64,000 high-fidelity wildfire simulation cases and implemented a Long Short-Term Memory neural network architecture.The model demonstrates strong predictive performance,achieving a coefficient of determination(R2)of 0.96 on training data,indicating excellent agreement with the physics-based simulation outputs.By utilizing coordinates from five reference points to predict fire front movement,this approach offers a novel method for analysing fire dynamics in homogeneous fuel beds with an average deviation of less than 2.5%.Combining the strengths of physics-based modelling and deep learning,our research enhances fire spread prediction accuracy of over 95%while significantly reducing computational demands.Future efforts will focus on refining the model,expanding the dataset,and incorporating additional variables to improve predictive capabilities and operational applicability.
基金Project(51178201) supported by the National Natural Science Foundation of China Project(2011CDB292) supported by the Natural Science Foundation of Hubei Province,China
文摘An active pipe-embedded building envelope, which is an external wall or roof with pipes embedded inside, was presented. This structure may utilize the circulating water in the pipe to transfer heat or coolth inside directly. This kind of structure is named ＂active pipe-embedded building envelope＂ due to dealing with the thermal energy actively inside the structure mass by circulating water. This structure not only deals with thermal energy before the external disturbance becomes cooling/heating load by using the circulating water, but also may use low-grade energy sources such as evaporative cooling, solar energy, and geothermal energy. In the meantime, this structure can also improve the indoor thermal comfort by tempering the internal wall surface temperature variation due to the thermal removal in the mass. This work further presents the thermal performance of this structure under a typical hot summer weather condition by comparing it with that of the conventional external wall/roof with numerical simulation. The results show that this pipe-embedded structure may reduce the external heat transfer significantly and reduce the internal wall surface temperature for improving thermal comfort. This work also presents the effects of the water temperature and the pipe spacing on the heat transfer of this structure. The internal surface heat transfer may reduce by about 2.6 W/mE when the water temperature reduces by 1℃ as far as a brick wall with pipes embedded inside is concerned. When the pipe spacing reduces by 50 mm, the internal wall surface heat flux can also reduce by about 2.3 W/m2.
基金supported by the National High Technology Research and Development Program (863) of China(No. 2006AAZ309)
文摘The fluorescence staining method and scanning electron microscopy （SEM） were used to study the effect of ozone （O3） inactivating Cryptosporidium in water and cell ultrastructures variation to shed light on the mechanism of inactivation preliminarily. Results indicated that O3 had a stronger inactivating capability. When the concentration of O3 was above 3.0 mg/L and the contact time was up to 7 min, a significant inactivating effect could be achieved. The turbidity on inactivation effects was also found to be statistically significant in artificial water. With increases in turbidity, the inactivating effect decreased. Inactivation rate improved with a temperature increase from 5 to 25℃, but decreased beyond this. The inactivating capability of O3 was found to be stronger under acidic than that under alkalic conditions. When the concentration of organic matter in the reaction system was increased, the competition between Cryptosporidium and organics with O3 probably took place, thereby reducing the inactivation rate. In addition, the cellular morphology of Cryptosporidium varied with different contact times. At zero contact time, cells were rotundity and sphericity, at 60 sec they became folded, underwent emboly, and burst at 480 sec, the cell membrane of Cryptosporidium shrinked and collapsed completely.
基金supports from the General Program (No. 31871016)the National Key Scientific Instrument and Equipment Development Projects (No. 61827806) from the National Natural Science Foundation of China+3 种基金the National Major Science and Technology Projects (No. 2018ZX10732401-003-007)the National Key Research and Development Program (No. 2016YFC1101302) from the Ministry of Science and Technology of Chinathe National Natural Science Foundation of China (No. 81770719)Science and Technology Department of Zhejiang Province (No. 2019C03029)
文摘Organ-on-a-chip systems have been increasingly recognized as attractive platforms to assess toxicity and to develop new therapeutic agents.However,current organ-on-a-chip platforms are limited by a“single pot”design,which inevitably requires holistic analysis and limits parallel processing.Here,we developed a digital organ-on-a-chip by combining a microwell array with cellular microspheres,which significantly increased the parallelism over traditional organ-on-a-chip for drug development.Up to 127 uniform liver cancer microspheres in this digital organ-on-a-chip format served as individual analytical units,allowing for analysis with high consistency and quick response.Our platform displayed evident anti-cancer efficacy at a concentration of 10μM for sorafenib,and had greater alignment than the“single pot”organ-on-a-chip with a previous in vivo study.In addition,this digital organ-on-a-chip demonstrated the treatment efficacy of natural killer cell-derived extracellular vesicles for liver cancer at 50μg/mL.The successful development of this digital organ-on-a-chip platform provides high-parallelism and a low-variability analytical tool for toxicity assessment and the exploration of new anticancer modalities,thereby accelerating the joint endeavor to combat cancer.
基金supported by the National Natural Science Foundation of China(51506160,11472208,11472209)China Post-Doctoral Science Foundation Project(2015M580845)+1 种基金the Fundamental Research Funds for Xi’an Jiaotong University(xjj2015102)the Beijing Key Lab of Heating,Gas Supply,Ventilating and Air Conditioning Engineering(NR2016K01)
文摘A comparative optimal design of fluid-saturated prismatic cellular metal honeycombs （PCMHs） having different cell shapes is presented for thermal management applications. Based on the periodic topology of each PCMH, a unit cell （UC） for thermal transport analysis was selected to calculate its effective thermal conductivity. Without introducing any empirical coefficient, we modified and extended the analytical model of parallel-series thermal-electric network to a wider porosity range （0.7 ~ 0.98） by considering the effects of two-dimensional local heat conduction in solid ligaments inside each UC. Good agreement was achieved between analytical predictions and numerical simulations based on the method of finite volume. The concept of ligament heat conduction efficiency （LTCE） was proposed to physically explain the mechanisms underlying the effects of ligament configuration on effective thermal conductivity （ETC）. Based upon the proposed theory, a construct strategy was developed for designing the ETC by altering the equivalent interaction angle with the direction of heat flow： relatively small average interaction angle for thermal conduction and relatively large one for thermal insulation.
文摘The undisturbed ground temperatures are important for design of the ground heat exchangers in ground source heat pump （GSHP） systems. In this paper, the undisturbed ground temperatures measured in two different methods are presented. The investigation was carried out in two cases. The temperature measured with the direct method is assumed to give the correct undisturbed ground temperature profile. The temperature measured with indirect method overestimates the undisturbed ground temperature by 2.1℃ and 1.7~C. This difference is mainly caused by the circulation pump and ambient air to the fluid. Therefore, the results that are decreased about 2℃ as compared with the indirect measured are recommended to estimate the undisturbed ground temperature in situ measuring. A smaller pump or deeper borehole or mild weather would result in a more correct temperature. Because the undisturbed ground temperature is affected by many factors. Whether or not these conclusions are correct to other areas, this would need further investigation.
基金This research was funded by the Ministry of Higher Education Malaysia via the Fundamental Research Grant Scheme(FRGS/1/2020/WAB03/UPM/02/1)。
文摘Tropical peat comprises decomposed dead plant material and acts like a sponge to absorb water,making it fully saturated.However,drought periods dry it readily and increases its vulnerability to fire.Peat fires emit greenhouse gases and particles contributing to haze,and prevention by constructing fire-break canals to reduce fire spread into forest reserves is crucial.This paper aims to determine peat physical and chemical properties near a fire-break canal at different fire frequency areas.Peat sampling was conducted at two forest reserves in Malaysia which represent low fire frequency and high fire frequency areas.The results show that peat properties were not affected by the construction of a fire-break canal,however lignin and cellulose content increased significantly from the distance of the canal in both areas.The study concluded that fire frequency did not significantly influence peat properties except for porosity.The higher fibre content in the high frequency area did not influence moisture content nor the ability to regain moisture.Thus,fire frequency might contribute differently to changes in physical and chemical properties,hence management efforts to construct fire-break canals and restoration efforts should protect peatlands from further degradation.These findings will benefit future management and planning for forest reserves.
基金supported in part by the Chongqing Social Science Planning Project(2021BS064)Chongqing Construction Science and Technology Plan Project(Grant 2023-0187)+1 种基金Special Foundation of Chongqing Postdoctoral Research(2021XM2052)Scientific and Technological Research Program of Chongqing Municipal Education Commission(Grant KJQN202304703).
文摘Given the complexities of reinforced soil materials’constitutive relationships,this paper compares reinforced soil composite materials to a sliding structure between steel bars and soil and proposes a reinforced soil constitutive model that takes this sliding into account.A finite element dynamic time history calculation software for composite response analysis was created using the Fortran programming language,and time history analysis was performed on reinforced soil retaining walls and gravity retaining walls.The vibration time histories of reinforced soil retaining walls and gravity retaining walls were computed,and the dynamic reactions of the two types of retaining walls to vibration were compared and studied.The dynamic performance of reinforced earth retaining walls was evaluated.
文摘During coal mining, water resources may be polluted by acid mine drainage (AMD) if appropriate measures are not taken. AMD releases metals to the environment, which can be harmful to aquatic species and reduce biodiversity. There is a great deal of information available in the literature on the generation and treatment of AMD and this paper tries to summarize some of them in order to facilitate the choice of the most appropriate method for AMD treatment at a specific mining site. The objective of this study was to identify and describe different methods of treating polluted water from coal mining, and to discuss the choice of suitable methods at specific mining sites. Both active and passive methods of AMD treatment are discussed in order to provide a general picture of the measures that have been taken around the world by coal mining companies. From this study, we were able to conclude that in order to choose the appropriate method for a specific mining site it is necessary to analyze the chemistry of the acid water and the flow rate from that site. The cost, implementability and effectiveness of the method should also be considered. Minimizing the amount of drainage water generated is naturally the first choice of management strategy and the containment of the AMD is the second choice. The third alternative is the treatment of the wastewater.
基金supported by the National Key Research and Development Program of China(No.2018YFD0900701)the National Natural Science Foundation of China(No.42177246)+2 种基金Additional support was provided by Yunnan Province-Kunming City Major Science and Technology Project(No.202202AH210006)the convenience provided by workstation of academician Liu Yongding in Kunming(No.YSZJGZZ-2020018)The Natural Science Foundation of Hunan Province(No.2022JJ30691)also supported this research.
文摘Freshwater lakes globally are witnessing an escalation in the frequency and intensity of cyanobacterial harmful blooms.However,underlying factors influencing the succession or coexistence of cyanobacteria,especially filamentous ones,remain poorly understood.Lake Honghu,a Ramsar Wetland of International Importance with degrading aquatic ecological quality,served as a case study to elucidate the intricate relationship between environmental changes and cyanobacterial dynamics.Our analysis revealed a significant increase in the dominance of filamentous cyanobacteria,marked by high spatiotemporal variability in community structure.This dominance of filamentous diazotrophic cyanobacteria is attributed to a decrease in the ratio of dissolved inorganic nitrogen to total phosphorus and their capacity to utilize organic phosphorus in phosphorus-deficient conditions.Species-specific density variations were linked to diverse environmental factors,with total nitrogen or total phosphorus concentration remaining as a crucial factor influencing dominant cyanobacterial density fluctuations.The dominance of low-temperature-tolerant Aphanizomenon and Pseudanabaena was evident in spring and winter,whereas Dolichospermum and Cylindrospermopsis,which prefer higher temperatures,thrived in summer and autumn.Additionally,non-algal turbidity and heterogeneity can potentially alter the competitive outcome among filamentous cyanobacteria or foster coexistence under conditions of elevated temperatures and nutrient limitation.This study predicts that filamentous cyanobacteria may spread and persist in lakes spanning a wide trophic range.Current findings enhance our comprehen-sion of the dynamic responses exhibited by filamentous bloom-forming cyanobacteria in the face of environmental changes within shallow eutrophic lakes and provide valuable insights for lake managers involved in the remediation of degraded shallow lakes.
基金Funding information National Natural Science Foundation of China,Grant/Award Numbers:52476072,51936005Young Talent Support Project of Guangzhou Association for Science and Technology+1 种基金Guangdong Basic and Applied Basic Research Foundation(No.2024A1515030035)Guangdong Pro vincial University Innovation Team Project(No.2023KCXTD038)。
文摘Interfacial solar evaporation,which captures solar energy and localizes the absorbed heat for water evaporation,is considered a promising technology for seawater desalination and solar energy conversion.However,it is currently limited by its low photothermal conversion efficiency,salt accumulation,and poor reliability.Herein,inspired by human intestinal villi structure,we design and fabricate a novel intestinal villi-like nitrogen-doped carbon nanotubes solar steam generator(N-CNTs SSG)consisting of three-dimensional(3D)hierarchical carbon nanotube matrices for ultrahigh solar evaporation efficiency.The 3D matrices with radial direction nitrogen-doped carbon nanotube clusters achieve ultrahigh surface area,photothermal efficiency,and hydrophilicity,which significantly intensifies the whole interfacial solar evaporation process.The new solar evaporation efficiency reaches as high as 96.8%.Furthermore,our ab initio molecular dynamics simulation reveals that N-doped carbon nanotubes exhibit a greater number of electronic states in close proximity to the Fermi level when compared to pristine carbon nanotubes.The outstanding absorptivity in the full solar spectrum and high solar altitude angles of the 3D hierarchical carbon nanotube matrices offer great potential to enable ultrahigh photothermal conversion under all-day and all-season circumstances.
基金funded by Shenzhen Science and Technology Innovation Commission(Grant No.KCXST20221021111203007)General Research Grant(15221623)of the Research Grant Council(RGC)of the Hong Kong SAR,China.
文摘Development of individual building in existing district is common in high-density cities due to the limited space.Such development affects the local microclimate naturally,but the interaction is ignored in current building design practices.In this study,a comprehensive and systematic analysis is conducted to investigate the mutual impacts between new individual building design and local microclimate considering the interaction,and to identify the major influential building parameters on both local microclimate and building energy performance in subtropical urban area.A large number of high-resolution microclimate and building simulations are performed based on advanced GIS spatial analysis techniques under different building designs for the assessment of mutual impacts.A global sensitivity analysis is conducted to identify the major influential building parameters.The results show that different building designs lead to significant variation of local wind velocity(i.e.,−0.95 to+4.51 m/s)and air temperature(i.e.,−0.60 to+1.17 K),while the local microclimate results in a change in the building energy consumption from−41.75 to 291.54 kJ/m^(2).The major influential parameters on both pedestrian thermal discomfort and building energy performance are building height and overall heat transfer coefficient of the building envelope.This study provides valuable references for new building or rebuilding design in order to facilitate carbon neutrality and enhance thermal comfort in urban area.
基金the financial support provided by the National Key Research and Development Program of China through the Grant No.2022YFB4200902.
文摘With the rapid increase in solar photovoltaic(PV)installation capacity,the strain on grid transmission burden has intensified.A house energy management system is recognized as an effective solution to mitigate this grid burden.However,existing research has not fully explored the potential of battery utilization and the forecasting of uncertainties.In this paper,a novel multi-objective optimization framework based on the genetic algorithm-based method for the house energy management system is proposed,to enhance renewable self-consumption,improve on-site renewable self-sufficiency,and optimize economic benefits for users.The framework integrates an artificial neural network for predictions of meteorological data and user load at a 5-minute temporal resolution,enabling the simulation and optimization of the PV-battery-flexible load system.Emphasizing deferrable loads,constant-temperature control loads,and batteries,the proposed framework devises optimal strategies for distributed PV battery systems in residential.It harnesses load flexibility and battery storage capabilities while incorporating comfort assessment metrics.This approach significantly improves the system’s economic and technical performance metrics,with system self-consumption rate,self-sufficiency rate,and cost reduction ratio improved by 13.5%,11.3%,and 6.2%,respectively,compared to the basic strategy.Additionally,the optimization of the air conditioning system enhances alignment with the photovoltaic generation,resulting in a 9.8%reduction in energy consumption and a 9.4%decrease in electricity costs,while maintaining user comfort at an acceptable level.The proposed framework promotes the practical application of renewable management systems,highlighting renewable energy efficient utilization,grid dependency reduction,and user economic benefit increase.
基金supported by a grant(152079/18E)from the Research Grant Council(RGC)of the Hong Kong SAR,China.
文摘One of the challenges in construction of nearly and net ZEBs is how to truly achieve the nearly and net energy goals after building occupancy.Traditional building design standards and practices are mostly based on design performance evaluation,but practices show that many designed nearly/net ZEBs failed to achieve the energy goals after building occupancy.To facilitate the practical achievement of nearly and net ZEBs,recently most of the newly-released ZEB design standards have turned to post-occupancy performance evaluation,posing great challenges to nearly and net ZEB design.However,the detailed challenges have not be comprehensively investigated,and effective optimal design methods which can facilitate the achievement of nearly and net ZEBs under these standards are still absent.In this study,new challenges of nearly and net ZEB design under the post-occupancy performance-based design standards are fully investigated,and a risk-benefit based optimal design method is proposed to facilitate the achievement of nearly and net ZEBs under these standards.The newly-released ZEB standard in China is taken as an example to investigate the challenges and test the proposed method.Results show that nearly and net ZEBs designed using conventional design method have high risk in achieving energy goals under these standards due to high risk in satisfying the requirement regarding non-renewable primary energy consumption after building occupancy.The proposed design method is effective to facilitate achieving energy goals under these standards based on the risk that decision-makers would like to take.
基金This paper is supported by the National Natural Science Foundation of China(NSFC)through Grant No.51908204the Natural Science Foundation of Hunan Province of China through Grant No.2020JJ3008Supports of the Sweden’s innovation agency(VINNOVA-MIRAI)and the Crafoord Foundation are acknowledged.
文摘The building sector is facing a challenge in achieving carbon neutrality due to climate change and urbanization.Urban building energy modeling(UBEM)is an effective method to understand the energy use of building stocks at an urban scale and evaluate retrofit scenarios against future weather variations,supporting the implementation of carbon emission reduction policies.Currently,most studies focus on the energy performance of archetype buildings under climate change,which is hard to obtain refined results for individual buildings when scaling up to an urban area.Therefore,this study integrates future weather data with an UBEM approach to assess the impacts of climate change on the energy performance of urban areas,by taking two urban neighborhoods comprising 483 buildings in Geneva,Switzerland as case studies.In this regard,GIS datasets and Swiss building norms were collected to develop an archetype library.The building heating energy consumption was calculated by the UBEM tool—AutoBPS,which was then calibrated against annual metered data.A rapid UBEM calibration method was applied to achieve a percentage error of 2.7%.The calibrated models were then used to assess the impacts of climate change using four future weather datasets out of Shared Socioeconomic Pathways(SSP1-2.6,SSP2-4.5,SSP3-7.0,and SSP5-8.5).The results showed a decrease of 22%–31%and 21%–29%for heating energy consumption,an increase of 113%–173%and 95%–144%for cooling energy consumption in the two neighborhoods by 2050.The average annual heating intensity dropped from 81 kWh/m^(2) in the current typical climate to 57 kWh/m^(2) in the SSP5-8.5,while the cooling intensity rose from 12 kWh/m^(2) to 32 kWh/m^(2).The overall envelope system upgrade reduced the average heating and cooling energy consumption by 41.7%and 18.6%,respectively,in the SSP scenarios.The spatial and temporal distribution of energy consumption change can provide valuable information for future urban energy planning against climate change.
基金supports for the Science and Technology Project of Zhejiang Province(No.LGG21F030009)the Natural Science Foundation of Zhejiang Province(No.LY20F030010)the Key R&D Projects in Zhejiang Province(No.2020C01164)are gratefully acknowledged.
文摘Temperature and humidity are two important factors that influence both indoor thermal comfort and air quality.Through varying compressor and supply fan speeds of a direct expansion(DX)air conditioning(A/C)unit,the air temperature and humidity in the conditioned space can be regulated simultaneously.However,most existing controllers are designed to minimize the tracking errors between the system outputs with their corresponding settings as quickly as possible.The energy consumption,which is directly influenced by the compressor and supply fan speeds,is not considered in the relevant controller formulations,and thus the system may not operate with the highest possible energy efficiency.To effectively control temperature and humidity while minimizing the system energy consumption,a model predictive control(MPC)strategy was developed for a DX A/C system,and the development results are presented in this paper.A physically-based dynamic model for the DX A/C system with both sensible and latent heat transfers being considered was established and validated by experiments.To facilitate the design of MPC,the physical model was further linearized.The MPC scheme was then developed by formulating the objective function which sought to minimize the tracking errors of temperature and moisture content while saving energy consumption.Based on the results of command following and disturbance rejection tests,the proposed MPC scheme was capable of controlling temperature and humidity with adequate control accuracy and sensitivity.In comparison to linear-quadratic-Gaussian(LQG)controller,better control accuracy and lower energy consumption could be realized when using the proposed MPC strategy to simultaneously control temperature and humidity.
