Search

Infrastructure construction results in transportation cost and regional economy changes. Based on the exogenous infrastructure change of a county highway opening as a natural experiment, this paper uses the spatial difference-in-differences (DID) model to analyze the impact of highway construction in three different provinces of China from 2004 to 2017. It was proved that highway connectivity had no significant or negative impact on the economy of the counties in three provinces that the highway passes through. In addition, highway connectivity was claimed to have obvious spatial spillover effects, which could promote the economic development of the whole region. For counties belonging to provinces in different regions and stages of economic development, we establish a spatial DID model that integrates time and space dimensions to study the impact of expressways on county economic development, to make up for the traditional DID model's dependence on SUTVA assumptions, and to obtain spatial spillover effects. [ABSTRACT FROM AUTHOR]

The application of air source heat pumps is mainly restricted by the outdoor ambient temperature, which causes poor application effects in the severe cold region of China. This paper proposes an innovative hybrid energy system of "solar air collector + air source heat pump + energy storage" that is utilized to save energy for ultra-low energy building in severe cold region. The feasibility and performance of this hybrid energy system is studied in Hailar which is located in severe cold region of China. The hybrid energy system is introduced and the dynamic characteristics of the key components of the system are analyzed in combination with the local meteorological conditions. The results indicate that, in Hailar, where the outdoor heating calculation temperature is lower than −30 °C and solar energy resources are not particularly abundant, the peak inlet air temperature of the air source heat pump increases by no less than 10 °C and the coefficient of performance of the system is expected to be higher than 3.0 under extremely low temperature conditions. Warm air from solar air collector can be supplied for heating without ASHP operation if its temperature is higher than 25 °C. These results provide some references for the application of the hybrid energy system in the severe cold region of China. • The hybrid system applied in the severe cold region of China has be proposed. • Performance of the hybrid system has be investigated deeply. • The hybrid energy system can be used for passive ultra-low energy building. • The temperature range of air source heat pump application is broadened. [ABSTRACT FROM AUTHOR]

The application of a photovoltaic (PV) system for zero energy buildings is crucial to balance energy consumption. This paper investigated the potential of PV systems for buildings in different climate zones of China. The tilt angle, orientation, plot ratio, PV conversion efficiency and location were selected to study their influences on electricity production. The performance of the PV system was analyzed based on a residential building, and employed RETScreen in combination with TRNSYS. The results indicate that southwest China is the best place to develop zero energy buildings. Low-rise residential buildings can realize zero energy in China when the PV conversion efficiency is higher than 20%. However, an energy balance only occurs in the southwest when the PV conversion efficiency is 10%. For different building heights, with a high conversion efficiency (20%), the energy consumptions rates are less than 15 kW h/m2a all over China. In the southeast, the effect of the building shape on energy generation can be ignored due to the high solar elevation angle in the summer. Although the optimal tilt angle varies for different cities, the energy deviations are less than 10% when tilt angle is within 10° of the optimal angle. This study proposed a formula to evaluate the potential of a building PV system. The maximum difference between the simulated and calculated results is approximately 10%, which is reasonable and acceptable. This paper provides some references for the application of PV systems in zero energy buildings. [ABSTRACT FROM AUTHOR]

Previous studies show a decline in parent–child co-residence among the elderly. This study examined the effect of living away from adult children on upward intergenerational monetary transfers by analysing a 2006 survey of 19,947 persons aged 60 and above and selected from 20 provinces in China. Results indicate that elderly who were not co-residing but had at least one adult child living in another community/village within the city/county were likely to receive more intergenerational monetary transfers than those who were living with children. Living close to children, rather than co-residing with them, might be the primary living arrangement for older Chinese people in the foreseeable future. The findings have important programme and policy implications for countries such as China, which has the largest elderly population in the world. There is a strong need for the development of specific public care support systems focused on the elderly population, in general, and elderly in rural areas, in particular. [ABSTRACT FROM PUBLISHER]

External shading systems play a key role in reducing the solar radiation entering the buildings and improving the thermal and daylighting performance of buildings. This study aims to comprehensively investigate the external shading effect on thermal-optical performance of ultralow-energy buildings (UEBs) using field comparison test in cold regions of China. In particular, two identical real residential buildings are continuously monitored in a period: one as a reference zone and another as a study zone. The results highlight that the external shading device with different configurations can reduce indoor temperature fluctuations and the predicted mean vote (PMV) for UEBs during a hot summer. For non-air-conditioning conditions, the maximum temperature reduction of the shading zone is 0.8 °C, while the indoor temperature fluctuates within a small range of less than 2 °C. For air-conditioning conditions, external shading device with slats angle of 90° provides the best performance, with the energy-saving potential (P) of approximately 21.77%. In addition, as the slat angle (SA) and the shading to window ratio (SWR) decrease, the P decreases correspondingly. Moreover, the utilization of an external shading device does not have an absolute advantage in decreasing the indoor illuminance and eliminating indoor discomfort glare. If an external shading system significantly decrease the indoor luminance and illuminance, the external shading system may increase the indoor glare risk and fail to meet the indoor daylighting demand. • Field comparison test of ultralow-energy buildings were performed in cold regions. • Thermal-optical comfort and energy-saving versus ten conditions were quantified. • Shading effect of various configurations and fan-coil states were discussed. • External shading system has a high energy-saving potential of up to 22%. • External shading system may have a negative effect on natural lighting. [ABSTRACT FROM AUTHOR]

Load matching is an inevitable problem that restricts the development of photovoltaic (PV) system used in buildings. The objective of this paper is to solve this problem by conducting a load matching assessment and optimization of PV system in different climate zones of China. The influences of the tilt angle, orientation, PV plot ratio and building height on the achievement of zero energy buildings (ZEBs) were evaluated. The PV potentials of roofs and facades were analyzed and optimized based on self-sufficiency and self-consumption. Net load variance and the maximum electricity import were employed as indices to evaluate the performance of PV systems in different climate zones of China. The results of the load matching assessment show that electricity generations from roof PV systems in low-rise buildings can meet most of the energy demand (at least 70%) in all climate zones of China. East and west facades of mid-rise buildings have an advantage over south façades in Kunming and Guangzhou in terms of load matching. It is necessary to combine roofs, south, east and west facades to meet the ZEBs requirement of for high-rise building. When the heating/cooling demand is dominant, the tilt angle should be higher/lower than the latitude of the specific location. This research will be helpful in designing building PV systems in different climate zones of China. Load matching analysis is helpful in designing building PV system in different climate zones of China. The results show that east and west facades of mid-rise buildings have an advantage over south façade in Kunming and Guangzhou. It is necessary to combine roof, south, east and west facades to meet the requirement of ZEBs for high-rise building. Image 1 • Load matching with PV system were analyzed for zero energy buildings. • PV potential were investigated based on self-sufficiency and self-consumption. • The optimal combinations of PV system were obtained in different climate zones. • East and west facades have advantages over south façade in Kunming and Guangzhou. [ABSTRACT FROM AUTHOR]

• Effect of external venetian blind on nearly zero-energy buildings was studied. • Energy performance of external shading in different climate regions was quantified. • Multiple optimization design of shading arrangement parameters was discussed. • A new index was proposed for evaluating the energy efficiency of external shading. The development and promotion of nearly zero-energy buildings (NZEBs) is an inevitable trend of building energy conservation, and external venetian blind shading (EVBS) is one of the most effective technologies for NZEBs. Therefore, this study aims to analyze and optimize the energy-saving performance of EVBS for NZEBs in different climate regions of China. Based on EnergyPlus, the optimal shading arrangements of NZEBs are obtained by evaluating the shading performance of different shading slat angles, orientations, window-to-wall ratios (WWRs) and locations. The results show that the energy saving potential of EVBS for NZEBs is significant, especially in southwest of China. And the energy-saving trends of EVBS with different shading arrangements are similar regardless of the climates, and the maximum energy saving potential per unit window area of EVBS is obtained in slat angle of 0°, west orientation and low WWR. The total energy saving potential (P) gradually decreases first and then increases rapidly as the slat angle increases for all slat angle (0°~180°) shading conditions. And the multi-orientation shading effect is the sum of each single-orientation shading effect. In addition, the cooling efficiency index (CEI) is proposed to evaluate the importance of shading to reduce the cooling demand of buildings, and to guide the improvement of the self-performance of shading. This research will be helpful in guiding the application of EVBS for residential NZEBs in different climate regions of China. [ABSTRACT FROM AUTHOR]