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1.
张莉  徐士鸣 《暖通空调》2006,36(6):91-96
建立了变质量能量转换与储存(VMETS)系统充能和释能过程的动态计算模型,结合上海地区一办公楼的空调系统分析计算了采用溴化锂溶液为工质的VMETS系统的充能、释能特性,结果表明该系统有较高的性能系数(4·8)和较大的蓄能密度(413·81MJ/m3)。  相似文献   

2.
在阐述压气法隧道施工原理的基础上,建立了水–气二相流模型来模拟压气法隧道施工过程中超压空气驱替隧道周围土体的孔隙水的水–气二相流过程。该模型同时考虑了土体中气相和水相的流动以及水相和气相相互作用的影响,比较符合水–气二相渗流过程的物理意义。通过工程算例,计算出不同施工进度下开挖面和隧道混凝土衬砌上的空气损失速率以及空气入流对隧道周围土体渗流场的影响,结果表明:在均质的地质条件下,开挖面上的漏气速率一般为常数,而衬砌上的漏气速率将随着隧道长度的增加而线性增大。最后,提出了利用水–气二相流模型进一步提高压气法隧道施工的漏气量的数值模拟精度,需要深入研究的两点意见。  相似文献   

3.
以某地下大型厂房为例,把弗劳德数转化成具有相同物理意义的热量阿基米得数,对顶部送风系统模型试验所测的数据运用数理统计的方法进行适当的处理与分析,得出了模型与原型的气流流动都处于弗劳德数自模区的重要结论。  相似文献   

4.
Water is a basic necessity of man. Economical and efficient production or recycling of water is very much needed in today's world. Solar still has emerged as a life-saving technology to distil brackish water and produce drinkable water using solar energy. The aim of this project was to improve the performance of solar still by adding an air blower which creates a bubbling effect in the still due to which the evaporation rate increases. The bubbling effect using the blower makes the raw water to circulate and to distribute heat energy equally. The evaporated raw water was collected in the glass plate as drop particles. The drop condenses due to ambient air and finally distillate output is collected in the jar, which is placed outside the still. The solar still with air blower arrangement gave higher difference in efficiency and higher distilled output when compared with solar still without an air blower.  相似文献   

5.
变风量空调系统的建模与控制   总被引:2,自引:0,他引:2  
邢丽娟  杨世忠 《暖通空调》2007,37(11):115-117
介绍了变风量空调系统的基本原理。结合变风量空调系统的特点,在基于被控房间数学模型的基础上,将模糊控制和常规PID控制相结合,提出了一种模糊PID控制方法并将其应用于变风量空调室温控制中。  相似文献   

6.
地铁空调负荷分析及估算   总被引:5,自引:0,他引:5  
钟星灿 《暖通空调》2006,36(6):72-76
简要分析不同系统模式的地铁空调负荷组成。重点探讨非屏蔽门系统(闭式系统)的热源构成、热量分布规律,以及空调负荷的估算方法。  相似文献   

7.
通过对建筑外窗气密性检测的不确定度评定,找出主要影响因素并加以分析.  相似文献   

8.
樊金花 《山西建筑》2003,29(18):96-97
阐述了商场空调设计中新风量取值与人流密度的关系,就空调系统形式对能耗的影响进行了分析,提出了以集中送风系统为主,分散式系统为辅的商场空调设计理念。  相似文献   

9.
高大空间恒温空调气流组织设计方法研究   总被引:18,自引:2,他引:16  
提出了一套通用的高大空间恒温空调气流组织设计方法:在气流组织初步计算的基础上,用数值分析的方法得到最优的设计方案,并用模型实验进行验证或修正。该方法用于某高大空间实验室证明是可行的。研究同时发现,室内的温度场和速度场同时受到冷射流和热源的影响,因此以往单纯用射流理论进行的气流组织实际计算结果不能直接应用于精度要求较高的恒温空调系统中。  相似文献   

10.
Based on analysis of uncertainty, this paper presents grey system theory to handle the “grey” characteristic of IAQ. Grey comprehensive analysis of indoor air quality reveals that we should pay more attention to the air purification and humidity control in the design and maintenance of HVAC. In order to represent grey characteristic of IAQ system, the educed grey IAQ models can identify the variation intervals of key IAQ model parameters that are lack of directly measurable messages in practical situations. Furthermore, grey assessment is an effective multifactor comprehensive assessment method that can express the integrative influence of contamination indexes on indoor air quality. We can determine the IAQ grade and make comparison according to the grey incidence matrix R.  相似文献   

11.
宋雪原 《山西建筑》2014,(15):134-136
结合具体工程实例,运用当前常用的计算方法对高层宾馆机械加压送风系统的设计进行了评估,并从加压送风量、管道与送风口尺寸、机械加压送风机全压等方面对该场所的防烟设计进行了讨论,以供同类工程参考借鉴。  相似文献   

12.
百叶风口送风射流的数值模拟   总被引:10,自引:2,他引:8  
为简化风口入流边界条件的描述,提出用N个简单开口代替不同方向出流的百叶风口,建立了N点风口模型,据此模型对不同出流条件的百叶风口射流进行了数值模拟,并就轴心速度衰减,射流扩展角及断面流速分布等与实验数据进行了对比。结果表明,当N=1或3时,模拟结果令人满意。  相似文献   

13.
Zhang LZ  Zhang XR  Miao QZ  Pei LX 《Indoor air》2012,22(4):321-330
Fresh air ventilation is central to indoor environmental control. Total heat exchangers can be key equipment for energy conservation in ventilation. Membranes have been used for total heat exchangers for more than a decade. Much effort has been spent to achieve water vapor permeability of various membranes; however, relatively little attention has been paid to the selectivity of moisture compared with volatile organic compounds (VOCs) through such membranes. In this investigation, the most commonly used membranes, both hydrophilic and hydrophobic ones, are tested for their permeability for moisture and five VOCs (acetic acid, formaldehyde, acetaldehyde, toluene, and ethane). The selectivity of moisture vs. VOCs in these membranes is then evaluated. With a solution-diffusion model, the solubility and diffusivity of moisture and VOCs in these membranes are calculated. The resulting data could provide some reference for future material selection. PRACTICAL IMPLICATIONS: Total heat exchangers are important equipment for fresh air ventilation with energy conservation. However, their implications for indoor air quality in terms of volatile organic compound permeation have not been known. The data in this article help us to clarify the impacts on indoor VOC levels of membrane-based heat exchangers. Guidelines for material selection can be obtained for future use total heat exchangers for building ventilation.  相似文献   

14.
Although negative air ionizer is commonly used for indoor air cleaning, few studies examine the concentration gradient of negative air ion (NAI) in indoor environments. This study investigated the concentration gradient of NAI at various relative humidities and distances form the source in indoor air. The NAI was generated by single-electrode negative electric discharge; the discharge was kept at dark discharge and 30.0 kV. The NAI concentrations were measured at various distances (10-900 cm) from the discharge electrode in order to identify the distribution of NAI in an indoor environment. The profile of NAI concentration was monitored at different relative humidities (38.1-73.6% RH) and room temperatures (25.2+/-1.4 degrees C). Experimental results indicate that the influence of relative humidity on the concentration gradient of NAI was complicated. There were four trends for the relationship between NAI concentration and relative humidity at different distances from the discharge electrode. The changes of NAI concentration with an increase in relative humidity at different distances were quite steady (10-30 cm), strongly declining (70-360 cm), approaching stability (420-450 cm) and moderately increasing (560-900 cm). Additionally, the regression analysis of NAI concentrations and distances from the discharge electrode indicated a logarithmic linear (log-linear) relationship; the distance of log-linear tendency (lambda) decreased with an increase in relative humidity such that the log-linear distance of 38.1% RH was 2.9 times that of 73.6% RH. Moreover, an empirical curve fit based on this study for the concentration gradient of NAI generated by negative electric discharge in indoor air was developed for estimating the NAI concentration at different relative humidities and distances from the source of electric discharge.  相似文献   

15.
针对现有地下风道空气析湿量计算模型及方法的不足,提出以数值计算为基础的空气析湿量计算方法。分析了空气在风道内的析湿过程,建立了热湿交换数学模型,将空气状态方程与热湿交换方程进行联立形成控制方程组,采用单元分割法对控制方程组进行离散求解,对不同风道深度、不同时刻的空气析湿量进行动态计算。经实测验证,数值计算结果与实测结果吻合较好,数值计算结果的平均相对误差为1.66%。计算和实测表明,风道前端,气流等湿冷却,无水分析出;风道后端,气流减湿冷却,析湿量沿程减小。  相似文献   

16.
17.
卞康  王季楼 《暖通空调》2007,37(4):64-66
对2000—2006年在我国申请以及授权的关于蒸气压缩式空调机四个主要部件——压缩机、冷凝器、蒸发器、膨胀阀的发明及实用新型专利的数据进行了检索及统计,分析了近年来我国在这一领域的发展水平,间接反映出不同地区及行业不同单位的科研能力。  相似文献   

18.
水电站地下主厂房顶送风研究   总被引:9,自引:2,他引:9  
付祥钊 《暖通空调》1996,26(1):59-62
水电站地下主厂房的送风量很大,采用顶送风方式可避免大量占有用空间。用相似模型试验研究了这一送风方式,分析了送风口数目、位置、尺寸及送风风速对工作区温度和风速的影响,定义了几个因次参数;获得了无因次回归方程。  相似文献   

19.
空调设备的节能运行以及设备的初期投资和全寿命运行费用是用户、设计和施工单位均非常关心的问题。运用技术可行性、节能效果、设备初期投资以及全寿命成本综合分析的方法 ,对于多种空调风量控制方法进行了综合评判。空调风机的输出功率近似比例于其转速的立方 ,根据该负载特性 ,从调节范围、灵敏度、维护保养、可靠性等方面着重分析了基于晶闸管斩波技术的风机调速方案 ,分析认为在多种可供选择的节能运行方案中 ,该方案是廉价、高效、实效性强的空调风量控制和节能方案。针对某大厦进行了实例分析和对比 ,给出的分析算例支持了以上结论  相似文献   

20.
Indoor air pollution from the combustion of traditional biomass fuels (wood, cow dung, and crop wastes) is a significant public health problem predominantly for poor populations in many developing countries. It is particularly problematic for the women who are normally responsible for food preparation and cooking, and for infants/young children who spend time around their mothers near the cooking area. Airborne particulate matter (PM) samples were collected from cooking and living areas in homes in a rural area of Bangladesh to investigate the impact of fuel use, kitchen configurations, and ventilation on indoor air quality and to apportion the source contributions of the measured trace metals and BC concentrations. Lower PM concentrations were observed when liquefied petroleum gas (LPG) was used for cooking. PM concentrations varied significantly depending on the position of kitchen, fuel use and ventilation rates. From reconstructed mass (RCM) calculations, it was found that the major constituent of the PM was carbonaceous matter. Soil and smoke were identified as components from elemental composition data. It was also found that some kitchen configurations have lower PM concentrations than others even with the use of low-grade biomass fuels. Adoption of these kitchen configurations would be a cost-effective approach in reducing exposures from cooking in these rural areas.  相似文献   

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