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To investigate group differences in human perceptions, long-term and point-in-time measurements on indoor environmental parameters were conducted in 22 open-plan offices in Harbin, China and 1352 questionnaires were collected. The differences in human perceptions among gender, age, level of education, BMI and the location of subjects groups were analyzed. The comfort temperatures for the male subjects were 1.2 °C and 0.8 °C lower than those for the female subjects in summer and winter, which revealed the higher acceptance of female subjects to the higher indoor temperatures. The mean comfort vote for undergraduates was 0.7 higher than those for master and doctoral students in winter. The difference between Griffiths comfort temperatures and operative temperatures in the overweight group was 1.9 °C in summer and 2.5 °C in winter, higher than the normal weight group (1.8 °C and 2.1 °C) and the underweight group (1.3 °C and 1.7 °C), which revealed the lower tolerance of the overweight subjects to higher temperatures than other groups. The subjects who sat near windows had lower thermal comfort votes than the subjects at other locations in all seasons due to solar radiation, radiator heating and the draft caused by window opening. For indoor air quality, sound and light environment, the male subjects had higher comfort votes than those for female subjects, and undergraduates had higher comfort votes than master and doctoral students. Finally, the interaction of five groups on human comfort was also explored. This study can be used to take into account the difference between groups and decide the comfort systems. • Group differences in environmental quality in open-plan offices in a severe cold region were systematically analyzed. • The comfort temperatures for males were 1.2 °C and 0.8 °C lower than those for females in summer and winter, respectively. • The mean comfort vote for undergraduates was 0.7 higher than master and doctoral students in winter. • The sensitivity analysis of thermal sensation and the comfort temperatures among different groups was discussed. • Interaction of five groups (gender, age, etc.) on human comfort was explored. [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]

Subway station entrances serve as crucial links between urban environments and underground transit systems and are particularly vital in cities with cold climates. Specialized design strategies are essential to address user needs and promote safety and comfort, thereby encouraging sustainable travel in harsh winter conditions. This research utilizes data from Harbin and Shenyang, two winter cities in China, to explore the nonlinear influences of subway entrance attributes on passenger satisfaction through the combined use of gradient-boosting decision trees and asymmetric impact-performance analysis. The findings indicate that most key attributes of subway entrances impact passenger satisfaction asymmetrically, highlighting the significance of their hierarchical importance in generating satisfaction. These attributes are categorized into frustrators, dissatisfiers, hybrids, satisfiers, and delighters, based on their asymmetry levels. Considering the current performance of these attributes, the study identifies priority for improvement at Harbin and Shenyang's subway entrances. This aids urban designers and city managers in making informed decisions for urban development and enhancing the overall commuter experience in winter cities. [ABSTRACT FROM AUTHOR]

Near-surface PM2.5 concentrations have been greatly exacerbated by urban land expansion and dense urban traffic. This study aims to clarify the effects of multiple factors on near-surface PM2.5 concentrations from three perspectives of background climatic variables, urban morphology variables, and traffic-related emission intensity. First, two case areas covering multiple local blocks were selected to conduct mobile measurements under different climatic conditions. The observed meteorological parameters and PM2.5 concentration were obtained through GIS-based imaging. These interpolation results of air temperature and relative humidity reveal highly spatiotemporal diversity, which is greatly influenced by artificial heat emissions and spatial morphology characteristics in local areas. The PM2.5 concentration on measurement days also varies considerably from the lowest value of 44~56 μg/m3 in October to about 500 μg/m3 in December in Harbin winter and ranges between about 5 μg/m3 and 50 μg/m3 in Guangzhou summer. The correlation analysis reveals that both the climatic conditions and urban morphology characteristics are significantly correlated with local PM2.5 concentration. Especially for Guangzhou summer, the PM2.5 concentration was positively correlated with the street traffic emission source intensity with correlation coefficient reaching about 0.79. Multivariate nonlinear formulas were applied to fit the association between these factors and PM2.5 concentration with higher determined coefficients. And optimization strategies are thus suggested to improve the urban air quality in local-scale areas. This attribution analysis contributes to environmentally friendly urban construction. [ABSTRACT FROM AUTHOR]

Creating a comfortable indoor environment in education buildings is an important design objective. Climate change has resulted in rising summer indoor temperatures in the severe cold regions of China, and evidence of summer overheating risk in these regions has not yet been fully investigated. This study presents evidence of overheating in a university building in a severe cold region of China, discusses the potential of integrated shading devices for mitigating overheating, and proposes design ideas for the application of shading devices. Temperature monitoring and simulation were performed in a university building with natural ventilation located in Harbin, and various configurations of integrated shading devices were simulated using IES Virtual Environment software. The results demonstrate that 69% of classrooms were overheated; furthermore, south-facing classrooms could be overheated for up to 152 h during summer occupancy hours. This study finds that integrated shading devices reduce overheating hours by up to 59.2%. The design of appropriate parameters for shading devices can effectively improve indoor thermal comfort while maintaining daylight levels and controlling the increase in energy consumption. The methodology and results presented in this study offer a reference point and practical guidance for mitigating regional overheating, aiming to promote the improvement of regional standards and optimisation of thermal environments in the severe cold regions of China. [ABSTRACT FROM AUTHOR]

The aim of this research was to explore the objective and subjective physical environments of residential care facilities (RCFs) by studying 34 facilities in Harbin, Changchun, Shenyang and Dalian. A study that combines questionnaires and instrumental testing. Pearson's correlation and regression analysis were used to analyse the correlation between the measured value and the evaluation result and the impact on the results of the participants' personal background evaluations. The results showed that the brightness intensity ranged from 100 to 450 cd/m2, illuminance 200–550 lx and sound pressure level (SPL) 40–58 dBA. In reconstructed RCFs (RCFs converted from other buildings), the odour and other factors were significantly positively correlated with the satisfaction of participants. Seasonal changes had a significant impact on the level of different physical environments, particularly in the assessment of the thermal environment. Temperatures were highest in bedrooms, reaching 27°C. The correlation between the measured value and the evaluated satisfaction was high. The education level of participants was related to their satisfaction with the overall Indoor environmental quality (IEQ). Participants in the study were satisfied with the overall IEQ of the RCFs. These results can provide data-based support and act as a reference for IEQ research on RCFs. [ABSTRACT FROM AUTHOR]

High heating expenses are observed in numerous Chinese rural houses located in severe cold regions due to the high heating demand, inferior envelope performance and low-efficiency heating equipment. The local traditional heating methods include Chinese Kangs and coal boilers with water-based radiators. The intermittent operation and manual regulation of these systems result in significant temperature differences and inadequate thermal comfort. This study presents the cost-optimal envelope renovation solutions with the minimized lifecycle cost (LCC) during a 20-year discount period and CO2 emissions of annual delivered energy consumptions. A single-family detached rural house in Harbin was used as a case building, illustrating the typical state of comparable houses in this climate context. Simulation-based multi-optimization analysis was conducted in this study using the building simulation tool IDA ICE and its integrated optimization tool AutoMOO. The results indicate that the cost-optimal renovation solutions with intermittent and continuous heating can cut CO2 emissions by 30% and 40%, respectively. The LCC with intermittent heating is still 7% greater than its pre-renovation case, which may require external financial support to encourage the renovation conduction, while the LCC with continuous heating decreased by 8% after renovation. According to the comparison results, cost-optimal solutions have significant advantages in both reductions of LCC and CO2 emissions over standard-based solutions. Moreover, utilizing intermittent heating is more effective than continuous heating in demonstrating the positive impacts of envelope renovation on increasing average temperature, decreasing temperature differences and lowering occupied time at low thermal comfort levels. [ABSTRACT FROM AUTHOR]

Virtual reality (VR) modeling has been increasingly applied in the field of construction; however, research and progress in the design and evaluation of energy-saving building envelopes of residential structures in northern cold regions remain limited. The objective of this study is to identify less laborious methods to analyze the design of energy-efficient buildings using a back-propagation neural network (BPNN) combined with VR modeling to evaluate the building envelope structure. We first use the BPNN to construct an algorithm to calculate the heat transfer coefficient of the building envelope. Houses in Harbin are used as research objects, and a VR platform is used to construct architectural models of different envelopes. Results show that the error of the BPNN algorithm applied to the heat transfer coefficient identification of the building envelope is less than 5%, and that the VR software can realize the three-dimensional modeling of different energy-saving envelope structures, as well as facilitate the evaluation of energy-saving performance. The results can provide a theoretical basis for designers and decision-makers in the application of the BPNN and VR technology to the design and evaluation of building energy conservation. [ABSTRACT FROM AUTHOR]

Based on the simulation results of the typical rural ultra-low energy building (ULEB) in five different climatic regions of China, three indicative technical parameters for paralleled-loop exhaust air heat pump (PEAHP) R&D which are nominal heating-cooling capacity, maximum required fresh air to return air ratio (MFRR) and system energy efficiency grades were calculated and summarized according to the demand of indoor thermal comforts by using statistic method. The nominal heating-cooling capacities were determined according to the peak loads, which are 6.84-2.01 kW, 5-2.96 kW, 3.9-4.6 kW, 3.08-5.02 kW, and 3.4-0.46 kW in the ULEB of Harbin, Beijing, Shanghai, Guangzhou, and Kunming, respectively. To ensure both thermal comforts and energy conservation, during the heating season, full fresh air supply is suggested in Beijing and the 1:0.5 MFRR is suggested in Harbin, Shanghai, Guangzhou, and Kunming. During the cooling season, the 1:5 MFRR is suggested in Shanghai and Guangzhou, the 1:3, 1:1.5, and 1:0.5 MFRR are suggested in Harbin, Beijing and Kunming, respectively. The PEAHP energy efficiency grades 1~5 are 7.92~11.7, 7.58~11.5, 7.5~11.35, 6.12~9.27, and 4.64~7.03 during the heating season of Harbin, Beijing, Shanghai, Guangzhou, and Kunming, respectively, and are 2.33~3.54, 3.93~5.96, 4.61~6.98, 4.62~6.99, and 2.04~3.1 for the cooling season, respectively. [ABSTRACT FROM AUTHOR]