• Energy Research

China’s research on and specific implementation of energy saving for buildings are mainly concentrated in urban areas, but according to 2016 statistics, the rural population accounts for 42.65% of the total population, so rural housing has considerable energy-saving potential. However, the degree of attention to the energy consumption of rural houses needs to be improved. Regarding the research on and implementation of passive energy-saving strategies for residences, compared with centralized urban high-rise residences, rural residences mainly have independent courtyards, with a flexible layout and easier transformation. In this study, a system that uses the common cold lanes in traditional villages and buildings’ exterior walls was constructed, and the indoor spaces of courtyard buildings in southern Shaanxi were completely passively cooled in summer. This system can be completely separated from the supply of artificial energy by relying on the accumulation and buoyancy effects of air in patios and cold lanes and the hot-pressure ventilation in buildings to cool the buildings and greatly improve indoor ventilation efficiency. As the building is ventilated and cooled, the air wall formed in the system can effectively prevent direct contact between the outdoor and indoor temperatures and reduce the impact of thermal wall radiation on the interior. In previous studies on the passive design of courtyard houses, scholars considered the effect of thermal wall radiation on indoor temperature in simulations. Therefore, in this study, we also separately calculated whether to consider the difference between the situation with and without wall heat radiation (WHR) when simulating thermal conversion. The final results show that when the cooling system was adopted, the annual cooling load of the whole building was 4786.494 kW·h without WHR. However, with WHR, the cooling load reduction was 2989.128 kW·h, a difference of 1797.336 kW·h.

According to a Chinese building energy demand report of 2016, building consumption is accelerating at a spectacular rate, especially for urban public buildings. In this study, various design parameters that meet the principle of climate adaptation are proposed to achieve the unity of energy utilization and indoor thermal comfort level. According to the local energy conservation codes, five typical benchmark geometric models were established in Open Studio (Sketch-Up plug-in) for sites representative of various climates, meanwhile, adopting the engine of Energy Plus (EP-Launch) to calculate the instrument definition file (IDF), respectively, for assessing the coupling relationship between energy consumption as well as thermal comfort. Results implied that based on the time proportion (8760 h) that met the level 1 comfort range, total energy reductions of different Chinese climate regions were different. Among them, the severe cold zone (SCZ—Changchun) and hot summer and cold winter zone (HSCW—Shanghai) appeared to have the greatest energy saving potential with 18–24% and 16–19%, respectively, while the cold zone (CZ—Beijing) and mild zone (MZ—Kunming) approximately equaled 15% and 12–15%, and the saving space of the hot summer and warm winter zone (HSWW—Haikou) appeared relatively low, only around 5–7%. Although the simulation results may be limited by the number of parameter settings, the main ones are under consideration seriously, which is further indication that there is still much room for appropriate improvements in the local public building energy efficiency codes.

Evaporative cooling systems (ECS) in buildings, which are driven by cleaner and more sustainable energy, had been widely applied in recent years especially for the dry hot regions in summer. In this study, an investigation was conducted for office buildings by using ECS in Urumqi (China) from July to August 2021. Through subjective survey and objective measurements, 577 initial questionnaires and measured data were obtained. Outcomes showed that the indoor expectative temperature (Te) was received by 26.6 °C, 0.7 °C lower than neutral temperature (Tn). And the acceptable intervals for the 90% and 80% level were obtained at 27.1–28.9 °C and 26.4–30.3 °C, respectively. It appeared to possess a wider scope than that calculated by PMV algorithm, which further indicted that subjects have adapted to the local climate. Furthermore, the adjustment PMV models (ePMV, APMV) were found to have an effectively narrow gap comparing to the actual thermal sensation vote (TSV). The appropriate usage intervals of ePMV and APMV were quantified by Top < 27.6 °C/Top > 29.8 °C, 27.6 °C < Top < 29.8 °C, respectively. These findings may provide reference values for the revision of local energy-saving standard to some extent.

Abstract Horizontal space bears a great potential of rainwater, especially for the cities with an intense density of residential building in the middle and lower reaches of the Yangtze River (China). The rainwater collected on the roof has huge potential energy due to the altitude difference from the ground, which belongs to the clean and renewable energy. Previous studies on the indoor passive ventilation strategies generally depend on the solar energy and the wind energy, resulting in failing to apply the potential energy of rainwater. Here, we proposed a novel hydraulic-driven ventilation device. This proposed device is regarded as a renewable energy supplier, since it can realize the indoor air movement by utilizing the potential energy of rainwater collected on the roof. Based on the experimental testing, we found that the hydraulic-driven ventilation device has a good capability, in terms of driving air movement. Furthermore, the numerical testing was carried out, to evaluate the indoor ventilation performances in two testing rooms of the study building integrated with the proposed ventilation system. The thermal comfort demander was taken into account, to optimize the building space partition arrangement. According to the building energy assessment tool, the integration of the hydraulic-driven ventilation device (i.e., renewable energy supplier) and the building space partition arrangement (i.e., thermal comfort demander), contributes to improving the building energy saving potentials by 46% and 43% for the periods of plum rain season and summer, respectively.

Abstract Up to now, the storage technology of electric energy is not advanced enough, resulting in the excessive electricity usually to be wasted. Conversely, power off could emerge during the peak hours of electricity use, due to inadequate electric generation in the power plant. Therefore, the mathematical models, used to predict the heating and cooling loads in buildings, are necessary to be created. However, there is a considerable amount of energy consumed in the China’s residential buildings, whose heating and cooling loads are characterized by climate sensitivity. In this work, the residential buildings situated in China were regarded as the study buildings. The principal research contents are shown as follows: (1) by creating a digital meshing system for China, the hierarchy system of residential building area at country scale was established; (2) via inputting air temperature data into the digital meshing system, the hierarchy system of air temperature was created; (3) the quantitative correlation between air temperature and thermal load intensity of the residential building was explored, to construct the hierarchy system of thermal load intensity; (4) Combining the above three hierarchy systems, the mesh-based mathematical models for predicting the total day-round heating and cooling load in the near future at country scale was created. The mesh-based mathematical models is expected to perform a scientific evaluation for the heating and cooling load of the residential buildings, aiming at reducing energy waste by planning and preparing the right amount of energy supply in advance.