履带车辆行驶平顺性仿真及试验

基于虚拟样机技术,结合三维造型软件、有限元分析和多体动力学软件,对履带车辆行驶平顺性仿真技术进行了研究.建立履带车辆的刚柔混合虚拟样机模型及随机不平路面模型,生成平顺性仿真模型系统,通过在F等级随机路面行驶仿真,得到车辆行驶时驾驶员座椅位置振动加速度曲线,根据评价标准对车辆进行平顺性评价,并与实车试验测试数据的计算结果进行对比分析.结果表明,仿真模型系统及评价方法合理,可以为提高和改善履带车辆的机动性能提供有效的方法和手段.     

装载机座椅振动舒适性分析与评价方法

通过对相关标准进行分析,利用评估座椅的疲劳降低效率极限、总计权加速度、有效振幅传递率(SEAT)因子和阻尼试验中的最大传递率等指标,得到装载机座椅振动舒适性分析与评价方法,并利用一款实例座椅进行了X和Y向振动加速度测试,利用振动舒适性评估方法分析了其振动舒适性。     

Estimating thermal performance of cool colored paints

The purpose of this study is to investigate the thermal performance of cool colored acrylic paints containing infrared reflective pigments in comparison to conventional colored acrylic paints of similar colors (white, brown and yellow) applied on sheets of corrugated fiber cement roofing. Evaluated properties are: color according to ASTM D 2244-89, the UV/VIS/NIR reflectance according to ASTM E 903-96, and thermal performance by exposure to infrared radiation emitted from a lamp with the measurement of surface temperatures of the specimens with thermocouples connected to a data logging system.Results demonstrated that the cool colored paint formulations produced significantly higher NIR reflectance than conventional paints of similar colors, and that the surface temperatures were more than 10 °C lower than those of conventional paints when exposed to infrared radiation. The study shows that cool paints enhance thermal comfort inside buildings, which can reduce air conditioning costs.     

Thermal comfort in air-conditioned mosques in the dry desert climate

In Kuwait, as in most countries with a typical dry desert climate, the summer season is long with a mean daily maximum temperature of 45 °C. Centralized air-conditioning, which is generally deployed from the beginning of April to the end of October, can have tremendous impact on the amount of electrical energy utilized to mechanically control the internal environment in mosque buildings. The indoor air temperature settings for all types of air-conditioned buildings and mosque buildings in particular, are often calculated based on the analytical model of ASHRAE 55-2004 and ISO 7730. However, a field study was conducted in six air-conditioned mosque buildings during the summers of 2007 to investigate indoor climate and prayers thermal comfort in state of Kuwait. The paper presents statistical data about the indoor environmental conditions in Kuwait mosque buildings, together with an analysis of prayer thermal comfort sensations for a total of 140 subjects providing 140 sets of physical measurements and subjective questionnaires were used to collect data. Results show that the neutral temperature (T_n) of the prayers is found to be 26.1 °C, while that for PMV is 23.3 °C. Discrepancy of these values is in fact about 2.8 °C higher than those predicted by PMV model. Therefore, thermal comfort temperature in Kuwait cannot directly correlate with ISO 7730 and ASHRAE 55-2004 standards. Findings from this study should be considered when designing air conditioning for mosque buildings. This knowledge can contribute towards the development of future energy-related design codes for Kuwait.     

Overview and new developments in optical daylighting systems for building a healthy indoor environment

Optical daylighting technology can deliver natural light to a space in a building where daylight is limited. This study gives an overview of two optical daylighting systems for capturing natural light: light pipe systems and mirror sunlighting systems. The literature on optical system theories and developments is identified and commercial products for optical daylighting systems on the market are described. By using a survey of major applications for optical daylighting systems, this study provides practical advice to building designers and researchers and also shows a light pipe system and a mirror sunlighting system developed from this investigation as well as an evaluation of their performance. The evaluation measured the illuminance of the two optical systems installed in a test room and a living room. This study concluded that optical daylighting systems can provide adequate visual comfort and can save energy if they are carefully designed.     

Thermal sensation and comfort models for non-uniform and transient environments, part III: Whole-body sensation and comfort

A three-part series presents the development of models for predicting the local thermal sensation (Part I) and local thermal comfort (Part II) of different parts of the human body, and also the whole-body sensation and comfort (Part III) that result from combinations of local sensation and comfort. The models apply to sedentary activities in a range of environments: uniform and non-uniform, stable and transient. They are based on diverse findings from the literature and from body-part-specific human subject tests in a climate chamber. They were validated against a test of automobile passengers. The series is intended to present the models’ rationale, structure, and coefficients, so that others can test them and develop them further as additional empirical data becomes available.A) The whole-body (overall) sensation model has two forms, depending on whether all of the body's segments have sensations effectively in the same direction (e.g warm or cool), or whether some segments have sensations opposite to those of the rest of the body. For each, individual body parts have different weights for warm versus cool sensations, and strong local sensations dominate the overall sensation. If all sensations are near neutral, the overall sensation is close to the average of all body sensations.B) The overall comfort model also has two forms. Under stable conditions, people evaluate their overall comfort by a complaint-driven process, meaning that when two body parts are strongly uncomfortable, no matter how comfortable the other body parts might be, the overall comfort will be near the discomfort level of the two most uncomfortable parts. When the environmental conditions are transient, or people have control over their environments, overall comfort is better than that of the two most uncomfortable body parts. This can be accounted for by adding the most comfortable vote to the two most uncomfortable ones.     

Natural ventilation potential model considering solution multiplicity, window opening percentage, air velocity and humidity in China

The paper brings about a two-opening naturally ventilated building potential model considering solution multiplicity, window opening percentage, air velocity and humidity in China. Based on previous research by Yang et al. and Luo et al., this paper developed a revised model to estimate the natural ventilation potential. There are four main improvements: Firstly, counteract of wind and thermal pressure was included and method for multiple solutions was introduced accordingly. Secondly, the model considered the natural ventilation hours for windows opening percentage. Thirdly, wind velocity and humidity were considered lastly. Fourthly, cooling and heating hours were also estimated.In case study, the paper analyzes natural ventilation potential in cities in four typical climate regions in China. Results show that there are more natural ventilation hours than previous models estimated, especially in cold climate regions.Any parameter in this model can be changed according to practical situation, such as climate data, building orientation, window size, opening position, etc. All estimated information can provide reference for architects in early stages of building design. Meanwhile, this model can be used for energy efficiency estimation and indoor environment research.     

Passive cooling for air-conditioning energy savings with new radiative low-cost coatings

Passive cooling is considered as an alternative technology to avoid unwanted heat gains, to reduce urban heat islands and to generate cooling potential for buildings (limiting air-conditioning energy). According to materials and surface treatments, the roof can represent to be a major heat gain source from opaque elements of the building fabric, heating up the outer surface and increasing heat flow by conduction. This paper presents low-cost new radiative materials (1 ∉/m²) allowing to limit heat gains during diurnal cycle for hot seasons. To evaluate the relevance of these new substrates, their reflective UV-VIS-IR behavior are studied and compared to classical roofed materials available in industrial and developing countries. A 48 m² experimental roof having different surfaces (plate steel sheets, fiber cement, terra cotta tiles and corrugated sheets) allows to determine the temperature ratio δ between uncoated and coated materials. Up to 34% surface temperature gains are obtained for white coated CS, 25% for FC and ∼18% for TCT and PSS. According to uncoated materials for a surface temperature T₀ = 60 °C, simulations showed that the low-cost white opaque reflective roofs (50 m²) presented in this study would reduce cooling energy consumption by 26-49%.     

r北方某供热计量示范项目的调查研究

通过对我国北方某供热计量示范项目的调查,对各种供热计量方式的特点进行了分析。通过入户调查,研究了用户行为节能、散热器罩对散热量的影响、用户的热舒适感觉及两部制热价满意度。     

活动式建筑外遮阳设施对室内光环境的影响

针对常见的两种活动式建筑外遮阳设施,在其提供有效遮阳效果时,对建筑自然采光和室内光环境的影响进行了计算和分析研究,指出活动外遮阳百叶自然采光效果更为理想。