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Photovoltaic double skin façade (PV-DSF) offers a versatile solution to address the escalating energy demands of buildings by combining power generation and indoor air temperature adjustment functionalities. Most prior research concentrated on its summer performance, while the winter season receives less attention. This paper concentrates on its operation performance in winter, to provide an experimental framework for its efficient operation. In this regard, the performance of internal circle and thermal buffer mode (both are possible operation modes in winter) were compared via control variable experiments, and the feasibility of mechanical ventilation is also examined regarding the trade-off between the energy consumption of fans and additional energy benefit. These experiments were performed in the full-size experiment rig at Harbin, China, a city with severe cold climate. The experiment results conclusively demonstrate that the internal circle mode can outperform the thermal buffer mode on a cold, sunny day by 10.9%, and the total energy-saving potential can be further increased by 12.6% if fans are activated to enhance cavity airflow. While the experimental data during partly cloudy emphasizes the significance of a suitable operation schedule and shows that PV-DSF can only be switched to internal circle mode when cavity air is fully heated. • The performance of photovoltaic double skin façade (PV-DSF) in winter is studied. • A fully-size experiment rig is constructed to perform comparison experiment. • The internal circle mode can outperform thermal buffer mode by 10.9% in clear day. • The fans can speed up cavity airflow and improve total energy efficiency by 12.6%. • The results of this paper emphasize the importance of a real-time control strategy. [ABSTRACT FROM AUTHOR]

• Integrate natural gas, solar and geothermal energy into park-level integrated energy systems. • Study park-level integrated energy systems' characteristics in china's climate zones. • Propose a confidence interval combination method. • Propose a two-stage optimization model. Park-level integrated energy systems (PIESs) have a unique role in developing communities' energy infrastructure in more economical and sustainable ways. The design and operation of a PIES depend on the energy demand of buildings, which could be significantly affected by climate change. This paper presented the PIES in China's different climate zones (Harbin, Dalian, Changsha, and Haikou). The PIES integrating natural gas, solar and geothermal energy simultaneously produces electric, heating and cooling loads. A two-stage optimal approach was proposed in this paper to model the PIES mathematically. In the first stage, the worst-case scenario was obtained by the confidence interval combination method to optimize the minimum total cost. In the second stage, the operation strategies of following electric loads and following thermal loads were used to optimize the operation cost. The results revealed that the annual total cost of the PIES presented a v–shaped cost curve with the power generation unit (PGU) capacity from 400 kW to 2000 kW. PIES-1, located in Dalian, had the lowest total cost of $0.71 million. The carbon dioxide emissions had the same trend. When the PGU's capacity reached the optimum (1000 kW), the PGU's utilization rate was between 50% and 60% in all scenarios. From Harbin to Haikou, the operation cost gap between PIES-1 and PIES-2 narrowed from $0.18 million to $0.01 million. Moreover, PIES-1, located in Harbin, had the lowest CO 2 emissions. [ABSTRACT FROM AUTHOR]

The photovoltaic double skin façade (PV-DSF) is a cutting-edge building envelope renowned for its dynamic nature and power generation capabilities, which attracts substantial scientific attention. However, the current lack of experimental support makes it challenging to draw definitive conclusions about the influence of façade material. This study aims to address this gap by investigating the energy performance of PV-DSF with different façade materials, thereby establishing an empirical foundation for its optimization. In this regard, the full-size comparison experiments on PV-DSF with 20/40% photovoltaic (PV) glass as external façade and laminated/double glass as internal glass were conducted in Harbin, China. The EnergyPlus software is adopted for the simulation of lighting energy consumption. The results indicate that PV-DSF with 40% PV outperforms that with 20% PV, leading to significant reductions in total energy consumption in both summer (22.73%) and winter (16.84%). The double glass can prevent 0.49 MJ of total heat gain in summer, which is accompanied by a marginal 0.03 MJ increase in winter energy consumption. In total, for optimal annual performance, 40% PV and double glass are recommended as the façades of PV-DSF. The results of this investigation can provide an experimental foundation for PV-DSF optimization in sustainable building design. • This paper presents the semi-experimental study on photovoltaic double skin façade. • The impact of façade material on the net energy-saving performance is studied. • The 40% photovoltaic (PV) glass outperforms 20% PV glass in both summer and winter. • The double glass possesses great advantage in summer, with a tiny short in winter. • From the view of year-round operation, 40% PV and double glass are recommended. [ABSTRACT FROM AUTHOR]

• A multi-attribute group decision method based on the interval-valued intuitionistic fuzzy set is proposed. • A sustainability evaluation of an agricultural water-land-energy-carbon nexus is provided. • Multidimensional indicators are combined through stability, coordinativity and connectivity. • The water, land, energy and carbon subsystems of the agricultural system are quantified based on dual uncertainty. • The model is shown to solve real-world relationship management problems. The interactions between agricultural subsystems, resource scarcity and ecological degradation increase the need for agricultural sustainability assessments in relation to water, land, energy and carbon emissions. In addition, uncertainties caused by natural factors and human activities complicate sustainability assessments. Therefore, this study proposes a regional agricultural sustainability assessment method based on the water-land-energy-carbon (WLEC) nexus system under high uncertainty. This method couples the interval-valued intuitionistic fuzzy set (IVIFS) and multi-attribute group decision making (MAGDM) methods to quantitatively characterise and assess element management and corresponding relationships within the agricultural WLEC nexus system in a multidimensional manner. The paper is able to (1) clarify the role of the coupled agricultural "water-land-energy-carbon" nexus and (2) address the double ambiguity and uncertainty in the indicators and more objectively reflect the interval fluctuations of natural resources and social activities in both positive and negative scenarios. (3) Sustainability management of agricultural resources is carried out according to different regional conditions. The method was applied to Heilongjiang Province in northeast China, and the coupling of agricultural WLEC nexus system in 13 administrative regions of the study area was quantitatively analysed. The degree of agroecological sustainability from a multidimensional perspective is higher in Daxinganling and lower in the provincial capital, Harbin. The recommended range of groundwater use in the study area is [16%,28%] to ensure ecological sustainability when total agricultural output fluctuates between 285,395.18 and 404,495.33 billion yuan. This methodology helps policy makers understand the overall dynamics of agricultural sustainability in an environment of multiple uncertainties and gives suggestions for better assessing management. [ABSTRACT FROM AUTHOR]

• A new data center cooling system integrating heat recovery with free cooling is proposed. • The system can work selectively in four different modes according to conditions and demands. • Stable performance of each mode and dynamic performance in mode switching are obtained. • Annual power consumption and heat recovery analysis are conducted in five cities. Rapid growth of data centers has caused a huge increase in energy consumption. Utilizing natural cold resources and harvesting waste heat are two promising ways to reduce the total power consumption of data centers. This paper proposes an integrated system of free cooling and heat recovery. The system has four working modes: mechanical cooling, mechanical heat recovery, pump free cooling and pump heat recovery. Experimental results show that pump free cooling mode can achieve an energy efficiency ratio of 7.99 when outdoor temperature is 2 °C, and different modes can be switched smoothly. The applicability of this system has been evaluated in five different cities in China. The results show that annual average energy efficiency ratio can reach 6.18 and free cooling time can take up as high as 72.9% during operation in Xining. The system can harvest the most heat in Harbin, 7930.96 kW∙ h per year, while the least in Guangdong, 645.31 kW∙ h per year. This means that this new system has relatively great application prospects in northern cold cities of China, while is moderately limited in southern cities. [ABSTRACT FROM AUTHOR]

Roof receives heat directly from the solar radiation and outdoor air, and the heat transfer of the roof is often greater than that of any external wall. The building roof is usually overheated in summer, causing a great increase in the air conditioning load and negative effects on indoor thermal comfort. Thus improving the thermal insulation performance of the roof is essential for reducing air conditioning energy consumption and improving indoor thermal comfort. In this paper, an innovative pipe-embedded ventilation roof with outer-layer shape-stabilized PCM (named VRSP for short) was proposed. The heat gain is stored in the PCM to migrate excessive heat during the day and released through air ventilation at night. A three-dimensional transient-state heat transfer model of the VRSP system was built by CFD. The effects of phase transition temperature range of PCM, thickness of PCM layer and airflow rate in the ventilation duct on the thermal performance of the structure in five representative climate regions of China were evaluated. Results show that the optimum phase transition temperature ranges of PCM in severe cold region, cold region, hot summer and cold winter region, hot summer and warm winter region and mild region are 31–33 °C, 34–36 °C, 36–38 °C, 34–36 °C and 29–31 °C, respectively. The optimum thicknesses of the PCM layer are 25–30 mm, 25–30 mm, 30–35 mm, 25–30 mm and 20–25 mm, respectively. The suitable airflow rates are 1.5–1.9 m/s, 1.6–2.0 m/s, 2.1–2.5 m/s, 1.9–2.3 m/s and 1.4–1.8 m/s, respectively. The conclusion provides valuable guides for the application of VRSP under various climate conditions. • A pipe-embedded ventilation roof with shape-stabilized PCM is proposed. • Effects of physical properties of PCM and airflow rates are investigated. • The new system is optimized for its applications in different climate zones. • Considerable energy-saving effects are observed in Kunming, Harbin and Beijing. [ABSTRACT FROM AUTHOR]

Integrating photovoltaics into windows provides the possibility of including an additional function of energy production to a conventional building fenestration component. There is no doubt that electrical power can be generated on-site. However, the effect of PV windows on the indoor luminous environment of the space served by them has not been comprehensively researched. This paper investigated the daylight performance of integrating four types of photovoltaics (semi-transparent thin film Cadmium telluride (CdTe) solar cells with 10% and 50% transparency, crystalline silicon solar cells with and without crossed compound parabolic concentrators (CCPC)) to a window of a typical south-facing office under different Window-to-Wall Ratios (WWRs). Annual useful daylight illuminance (UDI), daylight uniformity ratio (UR) and daylight glare probability (DGP) have been analysed based on dynamic simulation using RADIANCE. The simulation results show that windows integrated with crystalline silicon cells and CCPC optics have the potential to provide best daylight availability when compared with standard double glazed windows and other tested PV window prototypes, if it is applied to rooms with large WWRs (e.g. 60% or 75% WWR) at high latitudes (e.g. city of Harbin). Its application also improves the uniformity of daylight spatial distribution and eliminates the risk of glare. Semi-transparent CdTe PV window with 10% transparency can also improve the percentage of working hours that fall into UDI 500–2000lux range, however, it will result in the most sharp illuminance contrasts within the room. Applying all of these tested PV windows can effectively reduce the possibility of glare. • Window integrated PV provides daylight control in addition to energy generation. • Comprehensive daylight analysis was undertaken for four different PV windows. • Dynamic daylight metrics UDI, UR and DGP have been investigated using RADIANCE. • The effect of different WWRs on PV windows' daylight performance was explored. • PV windows can reduce the possibility of glare and maximise use the daylight. [ABSTRACT FROM AUTHOR]

The critical to sustainable urban development that a robust bus transit system is constructed to alleviate urban congestion problems. Unfortunately, disruptions in bus transit systems can lead to dysfunction and threaten sustainable development. This paper proposed a vulnerability analysis model for constructing complementary urban bus networks (UBNs), which considers the actual capacity of the bus network at the speed of transport roads. In addition, the UBNs aimed analysis method is presented from three specific aspects: (a) utilizing the stochastic user equilibrium model and different traffic situations to measure the UBNs of passenger flow distribution according to multi-source data; (b) introducing the node capacity and structural, functional vulnerability analysis model by combining real traffic flows and the complex network theory; (c) analysing the vulnerability characteristics of UBNs cascading failures from different passenger flow distributions and increasing capacity parameters, and comparing with those under different attack methods. Then, the new vulnerability analysis model is applied to the Harbin trunk bus. Considering different attack scenarios, the UBNs show strong vulnerability in the case of high congestion. Compared with other deliberate attacks, the bus network based on the attack mode of the maximum intensity site is more vulnerable at different times. These insights could be used to inform a vulnerability-based spatiotemporal design of bus transit networks. • An urban weighted transit network model is developed using multivariate data. • Network vulnerability based on traffic situation is proposed. • The network shows significantly varied vulnerability behaviors throughout the operation. • The temporal estimation of the network vulnerability is more effective than traditional weighted networks. [ABSTRACT FROM AUTHOR]

Cryopreservation in the temperature range from −120 °C to −60 °C is an important way to achieve high-quality food storage. In this paper, an in-depth quantitative thermodynamic comparison of two-stage cascade cycle, Linde-Hampson cycle and reverse Brayton cycle was carried out in the temperature range from −120 °C to −60 °C. Aspen HYSYS was used to invoke advanced genetic algorithm in MATLAB to optimize the system parameters. The two-stage cascade system performs best at the evaporation temperatures above −80 °C, achieving a COP of 0.97 at −60 °C. The Linder-Hampson system performs best when the evaporation temperature is below −90 °C, achieving a COP of 0.35 at −120 °C. In order to further explore the impact of environmental change on the system performance, five typical cities in China were selected to analyze the seasonal performances of the three systems. The seasonal analysis demonstrated that Harbin has the highest latitude and its seasonal energy efficiency ratio is significantly higher than other cities, the performance of the two-stage cascade system fluctuates more obvious within 24-h. What's more, the Linder-Hampson system has the lowest annual investment cost and annual operating cost at the evaporation temperature lower than −90 °C, as well as the lowest emissions of CO 2 and SO 2. • Thermodynamic characteristics of different refrigeration systems are studied. • Two-stage cascade system performs best at evaporation temperatures above −80 °C. • Linder-Hampson system performs best at evaporation temperatures below −90 °C. • The seasonal energy efficiency ratio of Harbin is visibly higher than other cities. [ABSTRACT FROM AUTHOR]

• Capture appropriate models in the discussion of TNn, TN5d and CR. • TNn and TN5d extreme events influence on pavement temperature with depth. • Identify the low-temperature performance based on winter temperature extremes. Winter temperature extremes are of major interest due to their potential damaging impacts related to pavement temperature and thermal cracking. In the present paper, three climate indices are adopted to describe the feature of winter temperature extremes. Statistical models for indices are analyzed based on the observed data in Harbin. The threshold values with their 99.9% cumulative frequency are proposed. Experiments were carried out in order to investigate the impacts of winter temperature extremes on pavement temperature and low-temperature performance of asphalt mixture. The results show that Weibull distribution is an appropriate model in the discussion of air temperature and its duration, and Frechet is the best-fitted model for the rate of air temperature change. Comparisons of experimental results indicate the importance of winter temperature extremes to asphalt pavement temperature. The influence of low-temperature properties by different temperature conditions is also analyzed. The low-temperature performance in Harbin can be accurately quantified by linear interpolation. [ABSTRACT FROM AUTHOR]

Abstract This study provides new insights into the comprehensive energy and economic performances of Photovoltaic Shading Systems (PVSS) in multi-story buildings. A numerical shading model was developed to evaluate the shading effect from an upper PVSS row on its subjacent row. Simulation models based on EnergyPlus were developed to analyze the Net Electricity Consumption (NEC) of PVSS with different tilt angles and widths in different climates. Benefit per Capacity (BC) and the Cost of Benefit (CB) indicators were used to analyze the economic performances of PVSS. Finally, the optimum PVSS tilt angles and widths in different cities were obtained. Harbin, Beijing, Changsha, Kunming, and Guangzhou, were selected as representative cities for different geographical and climatic conditions. The results indicate that the optimum tilt angles for PVSS installed in Harbin, Beijing, Changsha, Kunming and Guangzhou are 55°, 50°, 40°, 40° and 30°, respectively. Optimum PVSS width for all five cities is 1.156 m (7 columns of standard solar cells). PVSS installed, using the optimal design scheme, in multi-story buildings have better energy-saving potentials than either rooftop photovoltaic systems or traditional power supply modes for commercial buildings in China. Highlights • This paper focuses on the optimal design of photovoltaic shading systems. • A special PV module configuration was presented to reduce shading effect. • Numerical model embodying a profile angle was developed to analyze shading effect. • Optimum tilt angles and widths were obtained by analyzing benefit per capacity. [ABSTRACT FROM AUTHOR]

Abstract: Taxis share a high proportion of urban traffic volume and contribute a large proportion to urban air pollution. This paper addressees this context by exploring urban taxi air pollution emissions and possible reduction countermeasures. Based on a survey of Harbin taxis, we have developed different urban taxi pollution emissions models and considered taxi passenger occupancy and taxi average vacant ratio. To reduce taxi air pollution emission, this paper sets a reduction goal and puts forward three kinds of transport management policies. These are taxi market regulation, introduction of electric and Liquefied Petroleum Gas powered vehicles, and the introduction of dial-a-ride services. The paper provides recommendations for managing urban taxi development using these strategies. [Copyright &y& Elsevier]

The floating catkins generated by willow and poplar trees have been criticized for spreading germ and causing fire for decades. It has been found that catkins are with a hollow tubular structure, which made us wonder if the floating catkins can adsorb atmospheric pollutions. Thus, we conducted a project in Harbin, China to investigate whether and how willow catkins could adsorb atmospheric polycyclic aromatic hydrocarbons (PAHs). The results suggest that both the catkins floating in the air and on the ground preferred to adsorb gaseous PAHs rather than particulate PAHs. Moreover, 3- and 4-ring PAHs were the dominating compositions adsorbed by catkins, which significantly increased with exposure time. The gas/catkins partition (K CG) was defined, which explained why 3-ring PAHs are more easily adsorbed by catkins than by airborne particles when their subcooled liquid vapor pressure is high (log P L > −1.73). The removal loading of atmospheric PAHs by catkins were estimated as 1.03 kg/year in the center city of Harbin, which may well explain the phenomenon that levels of gaseous and total (particle + gas) PAHs are relatively low in the months with catkins floating reported in peer-reviewed papers. [Display omitted] • The natural floating catkins could remove atmospheric PAHs. • Catkins prefer to adsorb gaseous PAHs rather than particulate PAHs. • Adsorbing ability of catkins to low-rings PAHs was higher than airborne particles. • Atmospheric level of PAHs declined during the catkin-floating season. [ABSTRACT FROM AUTHOR]

In recent years, as drought intensifies and agricultural water consumption increases, it is of great significance to optimize the irrigation schedule to ensure regional food security. This paper constructs the distributed AquaCrop model and multi-objective genetic algorithm (NSGA - Ⅱ) simulation - optimization (MGSO) model to facilitate the development of a rational irrigation schedule. The distributed AquaCrop model considers the spatial variability of soil, climate, crops, and management practices, which can be batch calibrated using the XGBoost method. The MGSO model is for irrigation schedules under the combination of different Precipitation and ET 0. In this paper, crop yield, ET, and water use efficiency (WUE) were simulated and analyzed in 13 irrigation zones in Northeast China, where the existing irrigation schedules were analyzed and optimized. The results showed that the distributed AquaCrop model could simulate regional crops well. Crop yields in the study area ranged from 3 to 10ton/hm2. The western part of Heilongjiang province and the northern part of Jilin province has a higher yield. The simulation results of Heilongjiang Province are more accurate, and the relative error is minor. The joint distribution model constructed by the Frank Copula function can describe the joint probability distribution characteristics of precipitation and ET 0. According to the simulation results, each typical station has a different performance under the existing irrigation schedule under different situations. The crop yield and WUE of some stations changed significantly. The maximum and minimum yield difference was 22% for Harbin, 32% for Heihe, and 21% for Dunhua. It is mainly due to the irrigation amount in some scenarios that do not meet crop water requirements. Under the optimized irrigation schedule, the crop yield and WUE in different scenarios have been improved by the MGSO model in the Harbin station [Display omitted] • Distributed AquaCrop model was established based on batch parameter calibration processing. • Use a copula based joint probability of precipitation and ET 0 to define climate conditions. • New irrigation schedule considering both precipitation and ET 0 can improve yield and WUE of Crop. [ABSTRACT FROM AUTHOR]

• A micro-holes radiant plate without adding dynamic and piping system was designed. • Micro-holes radiant plate combines orifice plate air supply and radiant heat transfer. • The deviation between indoor and set temperature was within 1 ℃ for all types. • The maximum ratio of the radiant heat transfer quantity was close to 70 %. In order to alleviate energy shortage and maintain comfortable indoor environment, radiant air conditioning system is widely used. This paper designs and produces a miniaturized micro-holes radiant plate, which has the characteristics of orifice plate air supply and radiant heat transfer. The micro-holes radiant plate can be installation on the ceiling or sidewall without adding dynamics system and piping system. In order to explore the heating performance of the micro-holes radiant plate under different installation types, an experimental bench of air source heat pump micro-holes radiant plate heating system was built in Harbin, China, for laboratory heating. The experimental results showed that the indoor average temperature under various installation types could basically meet the set requirements, and the deviation was within 1 °C. The indoor horizontal temperature distribution was relatively uniform, and the temperature difference of each measuring point was less than 2 °C. The indoor vertical temperature difference was the smallest under the installation type with sidewall 50 mm from the ground at only 2.68 °C in the sitting position and 3.14 °C in the standing position, which meet China and ASHRAE standards. The ratio of the radiant heat transfer quantity under the sidewall heating was about 60 %, while the ratio under the ceiling heating was only about 30 %. The maximum ratio of the radiant heat transfer quantity was close to 70 % under the installation type with sidewall 50 mm from the ground. The experimental results provide theoretical support for the design and operation of air conditioning systems in severe cold regions. [ABSTRACT FROM AUTHOR]

• Air source heat pump fresh air unit with fresh and return air mixing was developed. • The supply air temperature deviation was within ±1 °C. • The heat pump COP was 2.46 when the outside temperature was −20.9 °C. • The heat pump COP was higher than that of the traditional heat recovery device. In order to ensure the indoor air quality of the building, in view of the problem of fresh air heating in severe cold regions, this paper proposes an air source heat pump fresh air unit with fresh air and return air mixing. The mixing process of the fresh air and return air is realized in the mixing box, which increases the inlet air temperature of the condenser, creates a suitable condensation pressure, and ensures the energy-saving and stable operation of the unit. In order to explore the operation effect, heating performance and energy saving of the unit, an experimental bench was built in Harbin for laboratory heating. The experimental results showed that when the return air volume was 1400 m3/h, the fresh air unit could operate continuously and stably under the conditions of ensuring the fresh air volume of 700 m3/h and the supply air temperature of 24.0 °C. When the outdoor temperature was 4.9 °C, the heat pump COP was 4.29. Even when the outdoor temperature dropped to −20.9 °C, the heat pump COP still reached 2.46, while the COP of the fresh air system combining electric preheating, heat recovery and air source heat pump was only 1.44, and the COP of the fresh air system combining electric preheating, heat recovery and electric heat was only 1.21. In addition, the heat pump COP increased with the increase of the return air volume. As the set temperature increased, the heat pump COP increased first and then decreased. [ABSTRACT FROM AUTHOR]

In this paper, a novel hybrid learning method is carried out to forecast urban air quality index (AQI). Wavelet packet decomposition (WPD) is firstly performed to decompose the original AQI data into lower-frequency subseries. Then, we improve the pigeon-inspired optimization through using the particle swarm optimization algorithm. The improved pigeon-inspired optimization (IPIO) approach is applied to optimize the initial weights and thresholds of extreme learning machine (ELM) and then the modified ELM (MELM) is employed to forecast the subseries respectively. Moreover, multidimensional scaling and K-means (MSK) clustering methods are utilized to cluster the forecasting outcomes into high frequency, medium–high frequency, medium–low frequency and low frequency subseries. Finally, MELM, as an ensemble approach, is applied to ensemble the subseries together and achieve the final results. To test the predictive precision of the proposed hybrid WPD-MELM-MSK-MELM learning method, AQI of Harbin in China is adopted to make short-term, middle-term and long-term predictions separately. Different decomposition approaches are utilized to compare with WPD, and the non-clustering hybrid model is also compared with the proposed method. The forecasting outcomes indicate that WPD is more suitable for predicting AQI and the proposed WPD-MELM-MSK-MELM learning method has better predictive performance on horizontal precision, directional precision and robustness than some existing methods and benchmark models in this paper. • A novel hybrid learning approach is presented. • Pigeon-inspired optimization is improved through using particle swarm optimization. • Extreme learning machine is modified by pigeon-inspired optimization. • Based on the multidimensional scaling and K-means clustering, the ensemble approach can enhance the predictable precision of AQI. [ABSTRACT FROM AUTHOR]

Using phase change material (PCM) into the building envelope is considered an effective thermal energy storage strategy to improve building thermal performance and reduce space heating/cooling loads. However, different phase transition temperatures and climatic conditions have a huge impact on application effect. This paper investigates the effects of walls containing PCM foamed cement on thermal performance and economy of single-story building in 5 different climate zones in China. The temperature, energy storage, energy consumption and the payback period for PCM foamed cement wall are analyzed by numerical simulation. The results indicate that the PCM foamed cement moderates the indoor and outdoor temperature differences in all 5 climate zones. Among which, Harbin (severe cold region) had the best increase in the south wall inner surface average temperature in January with an increase of 0.378 °C. The optimal phase transition temperature is close to the local annual average temperature except Harbin, and the energy saving rates are 20.17 % (Beijing), 15.87 % (Shenzhen), Shanghai(22.26 %), 37.02 % (Kunming). The shortest payback period is 5.95 years for the application of PCM foamed cement in Harbin, but in Kunming (mild region) at the current price, the investment cannot be recovered. [ABSTRACT FROM AUTHOR]

The energy-efficient driving of automatic train operation (ATO) system in high-speed railway systems has attracted more and more attention. Different from the energy-efficient automatic train control problem for metro trains, the traction/braking forces given by high-speed ATO systems are currently not continuous but discrete values corresponding to traction/braking notches due to the limited communication interface between ATO systems and rolling stocks. In addition, since high-speed trains are powered by single-phase alternating current, there is no power supply for train traction in neutral sections, which is introduced to separate two catenaries powered by currents with different phases. In this paper, we propose a discrete-space based mathematical formulation for the energy-efficient automatic train control problem for high-speed trains, where binary variables are introduced to indicate the traction/braking notch selections and to indicate whether a discrete space interval is a neutral section or not. The mathematical formulation is then transformed into a mixed integer linear programming (MILP) model, which can be solved by existing solvers. However, due to the discretization of the space the discrete traction/braking notches, the resulting MILP problem could be infeasible and the optimal driving strategy cannot be obtained. Hence, we present a novel relaxation method, i.e., the final braking notch relaxation method, to relax a few constraints in the final braking phase and to generate a feasible speed profile. Comprehensive experiments are investigated based on Beijing–Harbin high-speed railway line, where the energy consumption of the speed profiles with discrete (i.e., notch-based) traction/braking forces is slightly higher than that with continuous traction/braking forces. Moreover, the impacts of the neutral section locations and the effects of different numbers of traction/braking notches are deeply analyzed. • Energy-efficient automatic train operation for high speed railway lines. • A new optimal train control model with discrete notches and neutral sections. • Practically inspired final braking notch relaxation method to eliminate infeasibility. • The relaxation of discrete notches enhances computational efficiency. • Our model and method were tested based on data of Chinese high-speed railways. [ABSTRACT FROM AUTHOR]

• The SAGSHP system was established for a separated office building in Harbin, China. • The central zoning operation scheme of multi-mode switching buried pipes can maximize the energy efficiency of SAGSHP system. • The solar heat collection system can undertake 49.97 % of the heat supply through rational operation of SAGSHP system. • The usage of the central zoning scheme can ensure the annual soil heat balance in the SAGSHP system. • The economy of SAGSHP system is more sensitive to the initial investment and discount rate. In order to achieve the carbon peak and carbon neutrality strategy in China, A SAGSHP (solar-assisted ground source heat pump) system is developed and four partition operation schemes of quarterly multi-mode switching buried pipe were designed in this research. Four types of buried pipe interconnection were schemed including central type, N type, H type, diagonal type, and the field tests were conducted. The system performance, soil heat balance, economic characteristics of the SAGSHP system were analyzed and compared with the ASHP&CFB (Air source heat pump & Coal-fired boiler) system. The results show that the energy supply by the SAGSHP system can meet the heating, cooling and domestic hot water needs of separated buildings after adopting the partitioned multi-mode switching operation scheme. Meanwhile, the system's heat loss is decreased, soil heat balance is well maintained, and the system flexibility is improved. The graded use of solar and soil energy is well realized. The COPs of SAGSHP system in heating period and cooling period were 3.62 and 5.76 respectively under the control of the central zoning operation scheme of buried pipes. Solar energy can provide 49.97 % of the total heat supply of the system. Compared with the ASHP&CFB system, the SAGSHP system can save 9.84 t of standard coal after operating 13 years, and the equivalent reductions of CO 2 , SO 2 , and dust are 26.568 t, 0.1968 t, and 0.1476 t, respectively. The system economy is the most sensitive to the project's initial cost whereas the least sensitive to electricity prices. The research in this paper provides a feasible alternative for the energy supply of separated office buildings in Chinese the severely cold regions of China. [ABSTRACT FROM AUTHOR]

Rust belt cities are a special but important phenomenon in the world's industrialization landscape and city development trajectory. This profile analyses the struggling process and revitalization initiatives of Harbin, which was the first city established after the liberation of China, featuring the largest land area and highest latitude among all Chinese cities. The remarkable history of urban and industrial development once made Harbin the cradle of manufacturing in China, strongly supported by national government with concentration of SOEs. The city however has been suffering during the transition to a market economy. Its transition is painfully challenged by the strong socialist legacies of SOEs. This paper emphasizes that the new initiatives of Harbin, based on local endowments, cold climate condition and geolocation, demonstrate great potential for successful revitalization. Such strategic choices provide experiences and alternatives for other rust belt cities. [ABSTRACT FROM AUTHOR]

The heating period is very long in Harbin in China. This paper describes a field study in university classrooms and dormitories in heating period in Harbin. The survey shows that the neutral temperature in classrooms at 3 periods was 17.7̊C, 19.3̊C and 19.4̊C, and in dormitories the neutral thermal temperatures were 20.9̊C, 21.8̊C and 21.2̊C, respectively. The neutral temperatures were on the rising trend, which reflected human thermal adaptation to the heating environment. The different neutral temperatures in classrooms and dormitories were mainly caused by 2 aspects: Classrooms were warmer than dormitories, so more students could not accept classroom environment psychologically; Students have different regulative methods to the indoor environment. Clothing insulation in classrooms was bigger than in dormitories. Because of above reasons, students felt more comfortable in dormitories than in classrooms. [ABSTRACT FROM AUTHOR]

The world׳s urban population growth and economic development have led to the reshaping of metropolitan space layouts among residential, employment and shopping locations, generating growing mismatch between travel demand and transport services. A reliable method to accurately analyze mobility demand and underlying transport network systems and to identify areas with serious mismatch problems is important for the design of effective policy measures. In this paper, we make use of the wide deployment of GPS devices in vehicles in many cities today, to develop such a method. This approach is developed using GPS data collected from all taxis operating in the Chinese city of Harbin between July and September in 2013. It consists of four major steps. First, city-wide mobility patterns are modeled based on GPS trajectories. This model captures a set of key traffic characteristics for each pair of regions in the entire urban network, including travel demand, travel speed and route directness of travel paths. From this model, a set of indicators is then built to measure the road transport performance between the regions, and the areas with serious mismatch problems are subsequently pinpointed. Finally, the identified problematic regions are further examined and specific transport problems are analyzed. By applying the proposed method to the city of Harbin, the potential and effectiveness of this method are demonstrated. Moreover, with more and more urban vehicles being equipped with GPS devices, the designed method can be easily transferred to other cities, thus paving a way for the adoption of the presented approach for an up-to-date and spatial-temporal sensitive road network analysis approach that supports the establishment of a more sustainable urban transport system. [ABSTRACT FROM AUTHOR]

This paper focuses on the influence of urban morphology on pedestrian outdoor thermal comfort in Harbin, located in the severe cold region of northeast China. Three typical districts with different urban densities and street layouts were investigated. Field measurement and thermal comfort questionnaire survey were carried out from July 2020 to January 2021. Regression analysis was performed and the neutral physiological equivalent temperature (PET) range was 14.5–22.8 °C. In addition, the PET range was 7.9–27.3 °C when 80% of thermal votes were "acceptable". ENVI-met was verified and utilized to assess the mesoscale and street-scale impact of urban morphology on thermal comfort in hot and cold seasons. Measurement results shows that the PET variation caused by urban morphology was more significant in the transition season, with the maximum PET difference of 7.6 °C observed at the mid-rise district and the minimum value of 4.4 °C in the low-rise area. Simulation results indicate that the average building height significantly affects the background Ta and PET distribution within the block. Mean radiant temperature (MRT) and PET are highly correlated to sky view factor (SVF) in summer, while in winter, PET is related to SVF only in the low-rise district. Based on the thermal comfort calendar in both hot and cold seasons, shallow and medium canyons (0.5 < H/W < 1.5) are more favorable in severe cold climate, and the optimum streets are near the N–S orientation, followed by intermediate orientations, while deeper canyons (H/W > 1.5) are not recommended due to the lack of solar absorption. • The acceptable PET range is narrowed to 7.9–27.3 °C under different urban densities in the severe cold region. • The maximum PET difference caused by urban morphology was 7.6 °C and the minimum value was 4.4 °C in the severe cold region. • In severe cold region, shallow and medium canyons (H/W < 1.5) oriented in the N–S direction have better thermal comfort. • SVF is highly correlated to MRT and PET in summer, while there is no strong correlation between Ta and SVF in winter. [ABSTRACT FROM AUTHOR]

There has long been disagreement about the provenance of sandy dust deposits in Harbin city, Heilongjiang province, China. The present paper contributes to a better understanding of the source of sandy dust deposits in Harbin by the application of REE geochemistry. The REE composition of samples from sand–dust deposit events in Harbin was compared with that of three different grain size fractions (< 11 μm, 11–30 μm and 30–63 μm) of sandy soil samples from Horqin Sandy Land and Songnen Sandy Land. The results indicate that the REE distributions of all of the Harbin sand–dust samples are remarkably similar to each other, with distinct negative Eu anomalies and slightly negative Ce anomalies, indicating a stable provenance. Grain size exerts a significant influence on REE compositions, with a negative Eu-anomaly tending to develop with decreasing grain size. However, Ce is less influenced by grain size. The large lines of evidences, such as REE contents, distribution patterns, characteristic parameters, δEu (δEu = Eu anomalies values) vs. ΣREEs diagram, δEu vs. (LREE/HREE) diagram and (LREE/HREE) vs. La N (subscript N represents chondrite normalized values) diagram, indicate that REE composition of dust deposits in Harbin is quite similar to that of samples from Horqin Sandy Land, especially in the case of the 11–30 μm grain size fraction. This indicates that the Harbin sand–dust deposits are derived from Horqin Sandy Land and not from Songnen Sandy Land, and that material contribution of Horqin Sandy Land to Harbin dust deposits was mainly 11–30 μm grain-size fraction. The importance of the Horqin Sandy Land as a major source of Harbin sand–dust weather is supported by meteorological records and meteorological data. [ABSTRACT FROM AUTHOR]

Biomass gasification based building cooling, heating, and power (BCHP) system is an effective way of increasing and improving the use of biomass resources and distributed generation. The key step in designing a BCHP plant is to determine the best configuration in terms of the integrated performance from energy, economic and environment. This paper analyzes the configuration and operation strategy of the biomass gasification based BCHP system and proposes an integrated optimization design model combined a case study in Harbin, China. The configuration of the biomass BCHP system with thermal storage unit and hybrid cooling system is optimized to minimize the annual total cost (ATC) by the genetic algorithm (GA). Then, the energetic, economic, and environmental performances of the BCHP system are compared to the separation production (SP) system. The optimal results for the case study indicate that the optimal biomass gasification based BCHP system saves 45.4% ATC and reduces 90.4% CO 2 emission than the SP system. Finally, the contour-surfaces of ATC changed with the capacity configuration are obtained, and the validation and error analysis of the optimization model are verified. The results show that the error of the optimization ATC is only 0.00041% and the optimization speed of this optimization model is 12.4 times than that of the general cycle calculation. [ABSTRACT FROM AUTHOR]

This paper provides comprehensive research on the environmental quality of a semi-enclosed large-scale stadium during eight football matches. The field measurements during eight matches in a semi-enclosed large-scale stadium were firstly conducted and the corresponding questionnaire surveys on the subjects' comfort were collected. Then the questionnaires for the fuzzy analytic hierarchy process (FAHP) method were collected to obtain the weights of four comfort factors for large-scale stadiums. The measured environmental parameters were compared with limit values in different standards, including EN 16798–2, EN 12464–1, GB 3096 and WHO Air quality guidelines. The influence of environmental parameters on human perceptions was analyzed based on the data from field studies. Furthermore, the weighting scheme for semi-enclosed large-scale stadiums was discussed by comparing with other studies, which revealed that the users of the seme-enclosed large-scale stadiums had lower requirements for the acoustic environment than those of other types of buildings. The relationships between overall comfort votes and comfort votes for different factors were also explored, and the result showed that significant correlations existed between overall comfort and comfort factors, and the spectators were most sensitive to the thermal environment and least sensitive to the acoustic environment. The comprehensive research in this study can help designers and users to improve the building performance of semi-enclosed large-scale stadiums. • Thermal comfort and air quality are the two most important comfort factors during football matches. • TCV first increased with the increase in PET and then declined when PET was larger than 21.0 °C. • The preference vote of air velocity during matches was influenced by both air velocity and air temperature. • Spectators had higher light comfort votes for higher illumination levels than lower illumination levels. • The lively atmosphere during matches made spectators more tolerant of noise. [ABSTRACT FROM AUTHOR]

• Overcomes a significant obstacle in train-induced environmental vibro-acoustic issue. • Proposes a novel environmental vibration analysis system with a series of advantages. • Example of its excellent application in cold HSR sites is given and validated. • Blanks in current research on WIB vibration isolation in cold regions are well filled. • A dynamic response prediction formula with reference value is given and validated. Environmental vibration caused by high-speed trains and environmental noise pollution induced by such vibrations is one of the most challenging problems for sustainable urban development. One of the significant obstacles in analysis methods of vibration propagation path control is the inaccuracy caused by either over simplification of the interaction between train load and track above soil layers, or inappropriate expression of constitutive relationship and dynamic performance of soil below the track, especially in frozen soil, as difficulties and uncommonness exists in cross-application of multiple other disciplines into field of vibration and acoustics. A novel analysis system established in this paper, which is rare but very suitable for analysis of train induced environmental vibration and vibration isolation, builds a bridge for joint application of UM, ABAQUS, Python programming language and a series of derivation and calculation process, and manages to overcome the above obstacle to obtain a satisfactory solution. Field monitoring tests and accompanied numerical analysis based on parameters and properties determined by site investigation are carried out on soil vibration caused by CRH380B Harmony EMU train and its isolation at Harbin-Mudanjiang high-speed railway in China. Validations of the analysis system runs through the whole analysis process, including important processes and result data such as vertical wheel-rail force, velocity, vertical acceleration, characteristic frequency, and acceleration attenuation coefficient, etc. The results show that the established analysis system has high precision and wide application range, and vibration isolation effect with wave impeding barrier, who has better structural stability compared with other ones in cold regions under strong influence of seasonal and temperature physical effects, is excellent (vertical acceleration vibration level almost drop by more than 10 dB to below 72 dB, acceleration attenuation coefficient all below half and even a quarter in relatively close position). Blank in current research on wave impeding barrier vibration isolation of frozen soil sites in cold regions is well filled, and a dynamic response prediction formula is given and verified for the first time, which may have certain significance and reference value for other in-depth research. [ABSTRACT FROM AUTHOR]

Harbin to Dalian passenger dedicated line (HDPDL) was the first high-speed railway in the moderately deep seasonally frozen regions in the Northeast China. The roadbed–culvert transition section (RCTS) was paid special attention, as it was prone to uneven deformation. In this paper, the temperature field and its changing process of a typical RCTS at Siping site along HDPDL were discussed based on monitoring data. The results showed that during the freezing period (from November, 2010 to March, 2011), the thinner of the fill layer on the culvert, the higher temperature amplitude appeared in the RCTS. Due to the solar radiation difference on the sunny and shady slopes, the temperature in the sunny-slope was 1–3 °C higher than that in the shady-slope, and the difference increased as roadbed height increases. However, the culvert serves as a large ventilation duct, exchanging the amount of thermal rotation and weakening the temperature difference between the two sides. Numerical simulation of the temperature fields was carried out for discussing roadbed fill materials and culvert structures. The results indicated that, under the current design conditions, a pipe-style culvert shows a more stable thermal regime in the freezing period, while a box-styled culvert showed a more stable thermal regime in the thawing period. The anti-frost and insulation engineering measures were also discussed, and several critical design parameters were proposed and optimized. At last, it was found that the most suitable configuration was a box culvert with one section transiting to embankments, and this configuration was recommended for construction of high-speed railway in the seasonal frozen regions. [ABSTRACT FROM AUTHOR]

• Numerical model for a four-layer CdTe-based VPV glazing was developed. • The model was validated experimentally with a U-value of 0.92 W/(m2⋅K). • About 60% heat loss and heat gain can be reduced by VPV in cold and hot climates. • More than 40 kWh/m2 average power generation of VPV windows can be achieved. Vacuum-photovoltaic (VPV) glazing has attracted much attention due to its excellent thermal insulation performance and its ability to utilize solar energy. However, few simulation models have been established based on actual products and rarely have been validated by experiments. In this paper, a four-layer CdTe-based VPV glazing was developed and the corresponding numerical heat transfer model was established with the integration of a dynamic power generation model. The numerical model was then validated against both the results from the WINDOW program and a guarded hot box experiment. Afterward, the validated model was employed to analyze the energy and power generation performance of the VPV glazing in diverse climate zones in China with Harbin, Beijing, Changsha, Guangzhou, and Kunming used as representative cities. The numerical simulation results indicate that the U-value of the proposed VPV glazing is 0.89 W/(m2⋅K), which is in good agreement with the experimental results. Compared with a normal double glazing, the average energy reductions achieved with VPV glazing in air conditioning seasons are 128 kWh/m2, 23 kWh/m2, 45 kWh/m2, and 52 kWh/m2 in Harbin, Beijing, Changsha, and Guangzhou, respectively. In addition, the average annual power outputs of VPV glazing in Harbin, Beijing, Changsha, Guangzhou, and Kunming are 47 kWh/m2, 48 kWh/m2, 34 kWh/m2, 36 kWh/m2, and 45 kWh/m2, respectively. The numerical model developed in this study can be used for energy-saving potential analysis and optimization of VPV glazing in different meteorological conditions, the results of which could provide guidance for the effective application of VPV glazing. [ABSTRACT FROM AUTHOR]

Pavement integrated photovoltaic thermal (PIPVT) technology can utilize vast roads and pavements for electrical and thermal energy generation simultaneously. In this paper, a two-dimensional transient numerical model is developed for demonstrating the performance of a PIPVT system with two PIPVT modules and a 50 L water tank. With the mathematical model, the system performance is examined using simulations under three typical weather conditions, namely sunny, semi-cloudy, and cloudy. Besides, a long-term simulation is conducted in five climatic regions represented by five cities in China, including Lhasa, Harbin, Haikou, Shanghai, and Yinchuan, to study the seasonal and annual performance of PIPVT systems in different areas. From the viewpoint of both the first and second laws of thermodynamics, both energy and exergy analyses are performed for all the cases in different weathers and climatic regions. The overall energy efficiencies of sunny, semi-cloudy, and cloudy days are 33.10%, 34.74%, and 18.60%, respectively, revealing that the PIPVT system performs well on sunny days and semi-cloudy days, while the overall performance is unsatisfactory on cloudy days with extremely low solar radiation that rarely appears. Particularly, among the five climatic regions, the highland climatic region is ideal for PIPVT application with both the highest annual overall energy and exergy efficiencies of 37.89% and 14.17%, respectively. The icing phenomenon of the water in tubes arises in winter and late autumn in both the temperate monsoon climatic region and the temperate continental climatic region. The overall performance of PIPVT systems is best in western and southern China. [ABSTRACT FROM AUTHOR]

Abstract: Information and communication technologies (ICTs), such as mobile phones and the Internet, are increasingly pervasive in modern society. These technologies provide new resources for spatio-temporal data mining and geographic knowledge discovery. Since the development of ICTs also impacts physical movement of individuals in societies, much of the existing research has focused on examining the correlation between ICT and human mobility. In this paper, we aim to provide a deeper understanding of how usage of mobile phones correlates with individual travel behavior by exploring the correlation between mobile phone call frequencies and three indicators of travel behavior: (1) radius, (2) eccentricity, and (3) entropy. The methodology is applied to a large dataset from Harbin city in China. The statistical analysis indicates a significant correlation between mobile phone usage and all of the three indicators. In addition, we examine and demonstrate how explanatory factors, such as age, gender, social temporal orders and characteristics of the built environment, impact the relationship between mobile phone usage and individual activity behavior. [Copyright &y& Elsevier]

Abstract: In this paper, the yearly performance of a library building located in Harbin, China, equipped with a ground-coupled heat pump (GCHP) system, was simulated and its ground heat exchanger (GHE) was designed in the TRNSYS 17 environment. Utilizing the hourly load simulation results, a TRNSYS model was developed to analyze underground thermal balance of the entire system, obtaining the 30-year operation conditions of the reference building. According to simulation results, annual average storage temperature, the highest and lowest inlet temperature of the heat pump, factors that influence efficiency of the system, change as the number of boreholes changes. And the optimized length of heat exchangers was studied, as well as method of determining the concentration of antifreeze in heat-transfer fluid in cold regions. [Copyright &y& Elsevier]

Abstract: In China, adding space heating in residential buildings is normally scheduled at the end of October each year, with heat supplied by district heating systems. This paper describes a field study of thermal comfort conducted in Harbin during the winter from 2009 to 2010 before and after the space heating is added. The aim is to study human responses to thermal conditions in the two periods in cold climates. 23 buildings in six communities were investigated. 199 occupants from 135 families and 174 occupants from 104 families participated in the two surveys during the two periods, respectively. The neutral air temperature before adding the space heating is 25.1 °C, while during the space heating, it is 20.4 °C. The clothing insulation is 0.77 clo and 0.88 clo, respectively. If they were 0.88 clo instead of 0.77 clo before adding the space heating, the neutral air temperature should be 21.1 °C. Before and during space heating, more than 80% felt acceptable at the air temperature range between 17.5–24.0 °C and 19.0–26.5 °C for the two periods. The residents’ physiological acclimation may contribute to the differences. The preferred temperature is within the range of 23.0–24.0 °C and 21.5–24.0 °C, respectively. The preferred humidity is 47.7% and 40.5% during the two surveys. People felt cold generally before heating, while they felt comfortable at the same temperature range during space heating period. People often felt dry during heating when the relative humidity is lower than 30%, while they felt comfortable at the same relative humidity before heating. [Copyright &y& Elsevier]

To achieve efficient and reliable heating in severe cold regions below −20 °C, this paper investigates a R134a/CO 2 cascade air source heat pump (ASHP) system. Firstly, a simulation model is constructed and used for energy performance analysis. Then experiments are carried out for model verification and performance investigation. Finally, its performance is evaluated in detail with the meteorological data of Harbin under different working conditions for energy performance forecast. Simulation results show that the heating coefficient of performance (COP) increases with higher ambient temperature and lower water supply temperature. At the same time, the modeling errors on coefficient of performance (COP) are all within ±0.2%. The experimental results show that the proposed R134a/CO 2 ASHP can supply water above 50 °C with high COP up to 3.07 and 1.60 when the ambient air temperature is −5 °C and −45 °C, respectively. Furthermore, under four working conditions, the heating seasonal performance factors (HSPF) are all above 2.30 and the best is 2.39 for the −25 °C nominal operating temperature and the typical working condition of civil buildings (15 °C). Both the experimental data and the simulation results show that the proposed R134a/CO 2 cascade air source heat pump system can provide efficient and reliable heating in severe cold regions. • A CO 2 /R134a cascade ASHP is constructed and optimized in severely cold regions. • Experiments are carried to investigate its energy performance and verify simulation model. • Its COP can reach 1.60 at −45 °C air temperature, showing good heating performance. • Its estimated HSPF can reach 2.39 and 2.38 for civil and industry buildings in Harbin. • Rating condition of heat pump should be chosen based on weather conditions. [ABSTRACT FROM AUTHOR]

With high intensity of urban land development and dense population, urban high-density central area has obvious heat island effect, which has a great impact on thermal comfort. Taking Qiulin commercial district, the high-density central area of Harbin as the research object, this paper uses physical measurement and questionnaire survey to evaluate the outdoor thermal comfort. The results show that: (1) In high-density blocks of Harbin, there is a strong correlation between TCV and TSV, which is mainly affected by air temperature and globe temperature. And the correlation is stronger in transition season and winter than in summer; (2) The applicability PET in severe cold area was verified. The logistic regression method was used to obtain the range of neutral PET [12.99 °C, 19.89 °C] and the acceptable PET [5.14 °C, 27.15 °C]. At the same time, the 11-point TSV scale was verified to be accurate in assessing the thermal sensation in severe cold area; (3) Preferred PET in summer and transition season were 24.8 °C and 23.5 °C, respectively. Temperature expectation is the main factor influencing the difference of preferred temperature between cold and hot seasons; (4) Residents in severe cold area have become psychologically adapted to the cold environment due to long-term exposure to cold conditions, so that people are less sensitive to low temperatures in winter. In this situation it is important to have a general understanding of the outdoor thermal comfort in severe cold regions, which can guide planners to a better urban design. • Thermal comfort conditions of high-density urban center in Harbin, China were investigated. • The correlation between TCV and TSV is stronger in transition season and winter than in summer. • Neutral PET range in Harbin is 13–20 °C with the logistic regression method. • Preferred PET in summer and transition season were 24.8 °C and 23.5 °C. • Residents are less sensitive to low temperatures in winter due to psychological adaption. [ABSTRACT FROM AUTHOR]

Mobile phone data help us to understand human activities. Researchers have investigated the characteristics and relationships of human activities and regional function using information from physical and virtual spaces. However, how to establish location mapping between spaces to explore the relationships between mobile phone call activity and regional function remains unclear. In this paper, we employ a self-organizing map (SOM) to map locations with 24-dimensional activity attributes and identify relationships between users' mobile phone call activities and regional functions. We apply mobile phone call data from Harbin, a city in northeast China, to build the location mapping relationships between user clusters of mobile phone call activity and points of interest (POI) composition in geographical space. The results indicate that for mobile phone call activities, mobile phone users are mapped to five locations that represent particular mobile phone call patterns. Regarding regional functions, we identified nine unique types of functional areas that are related to production, business, entertainment and education according to the patterns of users and POI proportions. We then explored the correlations between users and POIs for each type of area. The results of this research provide new insights into the relationships between human activity and regional functions. • We establish location mapping between mobile phone call attribute space and geographical space. • We calculate correlations between clustered mobile phone users and POIs at base station area scale. • We find high correlations between user activities and regional functions (production, business, entertainment and education). • We find users' mobile phone call activities are extremely different between rural and urban areas. [ABSTRACT FROM AUTHOR]

Haze pollution in Harbin has been gradually alleviated in recent years, but it is still far from eliminated. Thus, precise and effective emission abatement of main chemical components like nitrate is urgently needed for further haze pollution control. This study aimed to estimate nitrate formation pathways, and the contributions of the emission sources of nitrogen oxide in urban Harbin, based on the measurement of isotope signatures in nitrate and the utilization of an improved Bayesian mixing model. The results showed that nitrate significantly aggravated particulate pollution in the heating season, and its driving role was enhanced as the pollution level increased. This study suggested that homogeneous reaction and heterogeneous reaction were the dominant conversion pathways of nitrate formation in non-heating season and heating season respectively, and the contribution of heterogeneous reaction increased as pollution levels increased. By considering isotope fractionation value (δ15N), this paper emphasized coal combustion as the dominant contributor of nitrogen oxide in urban Harbin, while biomass burning, mobile sources, and biogenic soil emissions played relatively weak roles in nitrate pollution. This study has critical importance to provide scientific theoretical bases for nitrogen oxide reduction in urban Harbin and air quality improvement reference in other severely polluted regions in China. Image 1 • Considering δ15 N fractionation is necessary for accurate NO x source apportionment. • Heterogeneous reaction played a vital role in nitrate formation in heating season. • Coal combustion was the dominant contributor to nitrate pollution in urban Harbin. [ABSTRACT FROM AUTHOR]

• A daylighting model and an energy simulation model of the vacuum PV glazing were developed. • The applicability and limitation of the vacuum PV glazing in different climates were investigated. • The vacuum PV glazing improves the energy performance of typical PV glazing. • The vacuum PV glazing can balance the daylighting availability and visual comfort. • The reversed and the reversible vacuum PV glazing can enhance the potential of the application. Amorphous silicon-based semi-transparent photovoltaic windows can produce renewable electricity and offer a certain amount of natural daylight for occupants. However, it has a deficiency as the absorbed solar energy would be partially transferred into additional cooling demand in summer. In this respect, a novel semi-transparent photovoltaic vacuum glazing is proposed to improve energy performance. The selection of appropriate glazing of an energy-efficient building should take into consideration the specific climate conditions. The daylighting behaviour of the glazing will also affect the daylighting performance as well as the lighting consumption. In this paper, the thermal performance, daylighting performance and overall energy performance of the proposed vacuum PV glazing in different climate regions have been investigated. A daylighting model was conducted by DAYSIM to evaluate the annual daylighting performance. It was found that the vacuum PV glazing can balance daylighting availability and visual comfort by providing sufficient daylight in the anterior half of the room and reducing daylight glare to the minimum level. The energy simulation by EnergyPlus demonstrated that the vacuum PV glazing has the energy-saving potential up to 43.4%, 66.0%, 48.8%, and 35.0% in Harbin, Beijing, Wuhan and Hong Kong, respectively. However, the applications of the vacuum glazing lead to additional cooling consumption in the moderate climate zone, such as Kunming. The results advanced the understanding on the applicability and limitation of the vacuum PV glazing in different climate backgrounds. Furthermore, the reversed and the reversible vacuum PV glazing were proposed to enhance the adaptability. The results suggest that the reversible vacuum PV glazing can act energy response in a more efficient way and fully utilize the energy-saving potential of the integration of the PV glazing and the vacuum glazing. [ABSTRACT FROM AUTHOR]

• Urban form factors that affect heating load in severe cold regions are discovered. • Heating load can be saved by 6.76% with every unit increased in surrounding FAR. • Heating load can be saved by 12.76% with every unit increased in surrounding RHR. • How urban morphology influence heating load in severe cold regions is discussed. • Urban design strategies are provided for reducing heating load in severe cold regions. Studies have suggested that the energy demand of buildings can be significantly influenced by urban morphological factors. However, little research has focused on urban-morphology-related heating energy consumption in severe cold regions, where buildings are facing greater pressure to save energy because of long heating periods. In this paper, the aim is to fill this knowledge gap through a combination of energy simulation and statistical analysis. First, taking 73 office buildings in Harbin as the study objects, the theoretical energy consumption (TEC) is stimulated and the external influence energy consumption (EIEC) of each building is obtained by subtracting the TEC from the measured actual energy consumption. Then, using regression analysis, the effects of 7 urban morphological factors on heating energy consumption are evaluated. The results indicate that greater building site cover (BSC), floor area ratio (FAR), building height (BH), road height-width ratio (RHR), total wall surface area (WSA), and lower green space ratio (GSR) are beneficial to the reduction of heating energy consumption. Among them, FAR is the most critical factors in saving heating energy by up to 10.820 kW·h/m2/y, with the addition of one more unit. This result confirms the significant role that energy saving-oriented urban morphology can play in making heating energy more efficient and sustainable in severe cold region cities. [ABSTRACT FROM AUTHOR]

• A solar lighting/heating system using spectrum-sensitive nanofluids was developed. • The light transmission efficiency was close to that of current solar lighting systems. • 1 m2 collection area provided 466.4 MJ of thermal energy in summer season. • The effect of operation condition on the system efficiency was explored. Solar lighting is considered as a promising technique, which has huge potential in conserving energy and relaxing the residents. However, current solar lighting systems used a filter to allow only visible light to enter buildings, releasing all the other energy contained in the long wave of the solar into the surrounding air. Such practice leaded to low efficiency of solar energy utilization and high costs. In this paper, a solar lighting/heating system was developed which used a hollow lens filled with ATO nanofluid to separate the long wave and short wave of solar energy. A series of tests were conducted to explore the performance of system. Results indicated that under the test condition of Case 1 (0.025%/0.0001% ATO/Graphite nanofluid, 100 L/h flow rate), the light transmission efficiency was 19.5% which was comparable to that of current solar lighting systems, and the heat absorption efficiency was 25.35%. The heat energy collected by the such a system from June to August (three months) in the city of Harbin was about 466.4 MJ in per square meter of collection area. The volume concentration of nanofluids had great influence on both the light transmission efficiency and the heat absorption efficiency. The flow rate had little influence on the light transmission efficiency, but had great influence on the heat absorption efficiency of the system. [ABSTRACT FROM AUTHOR]

Addressing both daylight maximization and glare control over the entire workplace is always challenging for developing the automated shading control system. For the sake of cost and space usage, it is impractical to mount multiple sensors or cameras for real-time daylight environment monitoring to guarantee the control precision. Cut-off control is popular while it cannot attenuate the glare caused by excessive diffuse daylight. This paper introduces a model-based shading control for predetermining shading positions at each time step. A Useful Daylight Illuminance paradigm modality called rUDI is proposed as a variable criterion added to assist the cut-off strategy for further eliminating glare. The controller could be developed through real-time daylight simulations and an optimizer based on the surrogate model. This method was implemented in a full-scale office in Harbin, China. The surrogate model grounded on the Radial Basis Function Neural Network (RBF) was trained, validated and test with the experimental data sets. The control strategy was further incorporated with an adaptive light-switch model. The comparative simulations were conducted, and their corresponding results were generated for evaluating their performance in visual comfort, daylighting and electrical energy savings, demonstrating the advantages of the proposed control approach in terms of its adequate performance. • A simplified controller with better daylighting performance based on simulation modelling is proposed for automated blinds. • A new metric concerning the dynamic illuminance distribution is proposed for automated blinds controller. • An optimizer derived from a machine learning algorithm is proposed for achieving predictive control. • Optimizing the indoor horizontal illuminance can effectively alleviate the glare caused by the intense diffuse daylight. [ABSTRACT FROM AUTHOR]

Vehicles are always in an alternating state of going and stopping at oversaturated signalized intersections, which not only reduces the operational efficiency of the intersections but also greatly increases the average fuel consumption of vehicles. The purpose of this study is to propose a fuel consumption analysis method that can be adapted to the oversaturated signalized intersections. Considering queue effects, this paper proposed a way to define the judging criteria and the classification for the oversaturated state based on the intersection spacing, traffic demand, and the intersection capacity. The theoretical models were constructed for estimating vehicular fuel consumption towards two different oversaturated states and with/without automatic start and stop systems respectively, which was dependent on two main parameters of the delay and the stop that were confirmed by the definite number theory. The results show that the degree of saturation of the approach and the automatic start and stop systems have a great influence on vehicular fuel consumption at oversaturated signalized intersections, and the shorter spacing is expected for the oversaturated state II because of more deceleration and acceleration maneuvers. • A vehicular fuel consumption estimate model is proposed for the oversaturated signalized intersection. • The influence of the degree of saturation on fuel consumption is studied. • The influence of intersection spacing on fuel consumption is analyzed. [ABSTRACT FROM AUTHOR]

• Three CO 2 two-stage compression based refrigeration systems are compared. • Demonstrated the feasibility of CTRS + PC + PCRS. • Five typical climate representative cities in China are considered. • The new concepts of SEER and ESS were proposed. To discuss the application feasibility of CO 2 two-stage compression refrigeration system with parallel compression and solar absorption partial cascade refrigeration system (CTRS + PC + PCRS), a CO 2 two-stage compression refrigeration system was proposed for the purpose of commercial supermarket application. Some important parameters, including coefficient of performance (COP), energy saving share (ESS), and partial seasonal energy efficiency ratio (PSEER) are taken as the objective functions to make comparisions among basic CO 2 two-stage compression refrigeration system (BCTRS), CO 2 two-stage compression refrigeration system with parallel compression (CTRS + PC) and CTRS + PC + PCRS. China's five typical climate representative cities (Beijing, Harbin, Wuhan, Guangzhou, Chengdu) are considered in this study. The results indicated that the COP of CTRS + PC + PCRS increased by 47.28% and 14.28% in Harbin area, compared with BCTRS and CTRS + PC, respectively. When operating under subcritical and transcritical conditions, the maximum COP of CTRS + PC + PCRS increased by 31.71% (Wuhan) and 47.28% (Harbin) respectively compared with the BCTRS, and increased by 12.27% (Harbin) and 7.78% (Wuhan) respectively compared with the CTRS + PC. The ESS and PSEER were introduced to evaluate the energy-saving effect of the solar partial cascade system (PCRS) and the performance of the composite system, and the maximum ESS is 0.19 (Beijing). Compared with the BCTRS and the CTRS + PC, the PSEER is increased by 22.54% and 2.81%, respectively. The research results in this paper provide a theoretical basis for the application of CO 2 two-stage compression refrigeration system in the application of commercial supermarket. [ABSTRACT FROM AUTHOR]

• Two thermal comfort investigations were conducted in severe cold area. • The thermal neutral temperatures derived from the linear regression model and logistic model were compared. • The relationship between probability of opening windows and temperature difference was developed. In recent years, the indoor air temperature in residential buildings for space heating rose gradually in the severe cold area of China. Would people feel comfortable in a warmer environment? This paper focuses on the appropriate indoor air temperature in winter. Two field investigations were conducted on the indoor thermal environment and human adaptation in residential buildings with district heating in Harbin during two winter seasons from 2011 to 2014. Ten apartments and their residents were chosen as samples in each investigation. The investigations included measurements of physical environmental parameters as well as subjective questionnaires. The results show that when the indoor air temperature was higher than 24 °C, people would have a sensitive response and preferred a lower temperature. An ordinal logistic regression model was used to examine the result of the linear regression model. The neutral temperature derived from the logistic model is 0.5 °C higher than that from the linear model and the adjusted neutral temperature is 0.8 °C higher than the linear model. Detecting whether people felt "cool" or not and "warm" or not is relatively accurate with the logistic model. It is not sensitive to judge whether people felt "neutral" in low air temperatures. Thermal neutral temperature is not a suitable set-point of indoor air temperature. In the severe cold area of China, the indoor air temperature of 20 °C is suggested as the standard for space heating in residential buildings in terms of comfort and energy saving. [ABSTRACT FROM AUTHOR]

Achieving visual and seasonal thermal comfort is an intractable issue for automated shading controllers over multiple blinds serving large side-lit, open-plan offices, especially when the occupied positions are spatially and temporally transient. In the current literature, few proposals have accounted for this. This study describes a novel model-based shading controller to fulfill this gap by optimizing the vertical eye illuminance conditionally at any occupied place. The controller was generated through real-time daylight simulations and two surrogate model techniques (online and offline) based on the radial basis function neural network. The offline surrogate model can predict timely vertical illuminance at any occupied position in the worst scenarios, and the online surrogate model yields the best combined shading results in a timely manner by an accelerated optimization procedure. The accuracy of the customized prediction models embedded in the controller was verified. Comparative simulations were performed for an open-plan office in Harbin, China. The performance regarding visual comfort, daylighting, electrical energy savings, and seasonal solar heat gains were explored and evaluated, demonstrating the advantages of our proposed control approach. • A novel shading controller to maneuver multiple blinds for visual comfort and energy savings for open-plan offices. • Machine learning-based surrogate modelling was adopted into controller for acceleration in adjustment. • Vertical illuminance was used as optimization criteria to alleviate the glare caused by the intense diffuse daylight. [ABSTRACT FROM AUTHOR]