复叠式空气源热泵翅片管换热器的结霜因子研究

空气源热泵在冬季结霜会对机组的运行产生较大影响。本文实验机组为一台复叠式空气源热泵,室外侧换热器采用带亲水膜的翅片,在焓差实验室中进行室外温度在-18℃~6℃区间、相对湿度在70%~90%区间内的实验,研究空气源热泵的翅片管换热器的结霜量。实验结果显示:结霜量随时间增加而增加,并且接近线性关系;室外温度在-3℃~3℃时的结霜量最高,随着室外温度的下降,结霜量下降;室外湿度对结霜量的影响较大,在70%的相对湿度下,结霜量远小于80%~90%的结霜量;本文根据结霜时间、换热面积和盘管表面温度与空气露点温度与结霜量之间的关系,提出了结霜因子的概念,并得到结霜因子的范围为1.69~2.67×10-3kg/(m2·℃·h),其平均值为2.22×10-3kg/(m2·℃·h)。     

Design and testing of an innovative measurement device for tyre-road contact forces

The measurement of tyre-road contact forces is the first step towards the development of new control systems for improving vehicle safety and performances. Tyre-road contact forces measurement systems are very expensive and significantly modify the unsprung masses of the vehicle as well as the rotational inertia of the tyres. Thus, vehicle dynamics results are significantly affected. As a consequence, the measured contact forces do not correspond to the contact forces under real working conditions. A new low-cost tyre-road contact forces measurement system is proposed in this paper that can be applied to passenger cars. Its working principle is based on the measurement of three deformations of the wheel rim through strain gauges. The tyre-rim assembly is thus turned into a sensor for tyre-road contact forces. The influence of the strain gauges position onto the measurement results has been assessed through finite element simulations and experimental tests. It has been proven that, for a large variety of rims, the strain gauge position that leads to high signal-to-noise ratios is almost the same. A dynamic calibration procedure has been developed in order to allow the reconstruction of contact force and torque components once per wheel turn. The capability of the developed device to correctly estimate tyre-road contact forces has been assessed, in a first stage, through indoor laboratory experimental test on an MTS Flat-Trac^® testing machine. Results show that the implemented measuring system allows to reconstruct contact forces once per wheel turn with a precision that is comparable to that of existing high-cost measurement systems. Subsequently, outdoor tests with a vehicle having all four wheels equipped with the developed measuring device have also been performed. Reliability of the measurements provided by the developed sensor has been assessed by comparing the global measured longitudinal/lateral forces and the product of the measured longitudinal/lateral accelerations times the vehicle mass. A good agreement has been found during all the performed manoeuvres.     

太阳辐射对室外空气换热器性能影响的研究

太阳辐射对热泵系统的室外空气换热器的热工性能有显著影响。提出了通过修正换热器传热系数以考虑太阳辐射作用的计算方法，设计出了热泵系统的实验装置并由实测数据进行了计算，得出了有与无太阳辐射时的传热系数之间的关系式。该方法不但可以提高热泵系统的热工性能模拟和能耗分析的准确性，而且对热泵系统及其室外空气换热器的设计与安装具有指导意义。     

交通主干道旁室内外PM10分析研究

大气中含有大量悬浮颗粒物，这些颗粒物表面吸附了来自燃料燃烧、机动车尾气、工业粉尘、废弃物燃烧等排放物，对人体健康的危害很大。其中空气动力学直径小于10μm(PM10)的颗粒物危害尤其严重。叙述了室内外可吸入悬浮颗粒物PM10的类别、来源和特性，通过现场监测交通主干道旁室内外和远离主干道的室内外PM10的浓度，并分析了实验监测结果产生的原因和变化的规律。     

建筑室内人员有效新风量及其特征性分析

结合人体呼吸模型建立了室内人员所获得有效新风量的计算模型,并对不同通风模式、新风量大小和污染源强度影响下的有效新风量的特征性做出分析。研究结果表明,混合通风条件下的人员有效新风量要低于置换通风条件下的对应结果;同时,入室新风量的增大可以使人员有效新风量提高,但提高的程度取决于通风模式;此外,污染源强度的变化对人员有效新...     

校园生活与户外座椅设施设计

以大学校园户外生活为切入点,分析了户外座椅设施对校园生活的深远影响,并结合校园户外生活形态进行了全面系统的调查研究,找寻校园户外生活的独特魅力,指出相对于城市公共座椅而言,校园户外座椅设施应具有其鲜明的特征。在此基础上,提出适宜于当代大学校园的户外座椅设施设计以及整体布局的建议,以期为大学校园生活注入朝气与活力。     

户外广告设计中符号语境的构建

通过商品符号结构、符号与环境的契合度二方面来分析现代户外广告设计中符号语境的构建过程,并结合案例加以说明。阐述了符号语境的构建可以将广告中的信息塑造成更加完整的传播形态。从而使信息更好地得到传播,也能使受众更加容易接受、理解与选择,进而能够更好地实现有效信息的传递以及提高信息传播的价值,进一步了解符号语境的运用在户外广告中的重要作用。     

驾驶员对北京市道路交通标志的感知和理解

通过模拟在交通标志引导下到达指定地点的过程,研究了北京市道路交通标志信息量以及驾驶员脑力负荷对感知和理解道路交通标志的影响.在已有研究的基础上,改进了交通标志信息量的计算方法.相关分析结果表明,该方法很好地拟合了驾驶员对交通标志信息量的主观评价.方差分析结果表明:1)信息最的大小对驾驶员感知和理解交通标志没有显著影响;2)脑力负荷对交通标志识别率、决策时间、决策正确率以及决策确信程度有显著影响;3)脑力负荷对主观任务负荷和识别交通标志的时间没有显著影响.     

Energy consumption analysis on a dedicated outdoor air system with rotary desiccant wheel

A dedicated outdoor air system (DOAS) with rotary desiccant wheel is the combination of a desiccant dehumidification system and a vapor compression refrigeration system. An energy consumption model of this hybrid DOAS is established for its analysis. Coefficient of performance, COP, is appropriately defined for evaluation on performance of the hybrid DOAS. The results indicate that, compared with a conventional DOAS, energy savings are possible for the suggested DOAS, when solar energy or natural gas is used for regeneration. Ventilation air flow rate, temperature or humidity of outdoor air, as well as regeneration-to-process air ratio, influence the energy consumption and the COP of the hybrid DOAS, greatly.     

谈北京公馆的节能技术设计

北京公馆作为高档公寓,在设计中采用了钢结构、呼吸式玻璃幕墙、水源热泵系统、地板采暖系统、独立新风系统等多种节能措施。多种节能措施的综合运用,在建筑工程的可持续发展方面具有一定的探索意义。