Search

• 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]

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]

• 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 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]

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]

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]

• 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]