Search

• The performance of building PV system were analyzed in Hainan province. • The potential of PV system used on building roof was investigated. • Carbon emission reduction during 2020–2060 was calculated. • This study would provide references for using PV system in Hainan province. Energy balance in the building industry and the potential of building PV systems are indispensable to achieve carbon peaks and carbon neutrality in Hainan Province. This research investigated load matching for different types of buildings and the electricity generation potential of building PV systems in Hainan Province. The tilt angle, orientation, PV conversion efficiency and available area of the building were adopted as research parameters to analyze the chance of realizing zero carbon in the building industry. The potential of roof PV systems and economic analysis in Hainan Province were studied. The results show that when a high-performance PV system (20%) is utilized, the electricity demand of buildings can be covered, and 86.9% of the total electricity demand of Hainan Province can be provided by roof PV systems. If all available roof area was used appropriately, carbon emission reduction is up to 13.49 million tons CO 2 every year. The cumulative carbon emission reduction could be 408.7 million tons CO 2 by using roof PV systems during 2020–2060. The initial cost and pay back period were 117.4 billion CNY and 6.3 years, respectively. All residential buildings, office buildings and small hotels are able to achieve an energy balance when the PV conversion efficiency is 20%. Electricity generation reaches the maximal value when the tilt angle is 15°. When the tilt angle is in the range of 0° to 30°, energy generation is larger than 270 kWh/m2a, and the difference is less than 5%. Electricity production on the east and west facades is greater than that on the south façade. This research provides some references for using building PV systems in Hainan Province. [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]

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]