送风参数对空气源热泵制热运行的影响研究

针对夏热冬冷地区冬季采用空气源热泵供暖时出现的热力分层现象,通过实验研究了空气源热泵在不同送风角度和送风速度下室内温度场的分布特性,比较和分析不同送风角度和送风速度下室内垂直温差的变化关系。结果表明,当送风速度一定时,送风角度越小,室内垂直温差越小;当送风角度一定时,送风速度越大,得到的室内垂直温差越小。     

方形散流器送风参数对气流分布影响实验研究

本文目的是研究方形散流器的送风参数对室内气流分布的影响规律。在模拟建筑内区的空调实验室进行了实验，测出了不同送风参数下室内所有测点的温度和速度。对实验数据分析得出空气分布特性指标、温度不均匀系数以及速度不均匀系数与送风速度的关系曲线，并用TECPLOT软件实现了温度场、速度场的可视化。结果表明在室内热源和控制温度不变时，随着送风速度的增大，送风温度升高，送风温差减小，室内工作区的空气分布特性指标增大。     

柜式空调机在矩形空间使用效果的实验研究

实验研究结果表明,送风方向和送风速度挡的合理设置能使空调器达到良好的使用效果,柜式空调机组合工作时,两台空调机的相对位置、导风板的旋转角和出口风速对室内平均温度的影响较大。在合理的风速和机组组合下,送风方向与垂直面成90°以上角时,空调房间的温度分布更趋均匀。     

大温差送风技术在高精度恒温空调中的应用可行性

为了研究空调大温差送风技术在高精度、多扰量恒温空调中应用的可行性,采用CFD数值模拟分析了恒温室不同送风温差下温度场和速度场的均匀性,研究了恒温室在不同送风温差下不同扰量作用时的温度动态响应特性。结果表明,空调送风大温差下的温度场和速度场以及温度稳定性能满足恒温室要求。     

车站高大空间空调系统气流组织与热舒适性分析

兼顾人体热舒适和建筑节能的要求,对目前车站高大空间空调气流组织的数值模拟研究报道进行对比分析。分析结果显示,人们对高大空间建筑室内热舒适要求高于居住建筑和办公建筑;从满足人体热舒适角度出发,空调送风加地板辐射供冷方案适于夏季满员工况,地板辐射供热加空调加湿方案适用于冬季满员工况;高大空间的空调系统适宜采用上送上回的送风方式,其温度场和速度场均优于上送下回的空调送风方式;在高大空间内设置分层空调系统将在一定程度上降低空调能耗,且分层空调中送风速度对分层界面的位置影响较大,送风温差对高大空间分层空调的温度分布和流场分布有较大影响。     

夏季空调送风参数对室内温度场影响的分析

空调的送风参数对室内热环境有着重要的影响,特别是对温度场的影响尤为显著.以在夏季空调房间有新风引入的情况下.着重比较了不同送风角度、送风速度下的室内温度场的分布.以此为基础,得出最佳的送风速度与送风角度.     

孔板送风对壁挂式空调房间热舒适性的影响

为研究孔板送风方式对壁挂式空调房间热舒适性的影响,采用Airpak软件分别对在相同送风量和送风温度下采用传统射流送风和孔板送风的气流组织进行数值模拟,通过对温度场、速度场、PMV-PPD值的对比分析,评价两种送风方式下的室内热舒适性,并采用实验测试的方法,对模拟结果的准确性进行实验验证。结果表明:送风方式对室内热舒适性影响明显,孔板送风对室内气流组织的改进和热舒适性的提高有较显著效果,夏季工况采用孔板送风可以起到节省能耗的作用。     

基于工位空调冷风感的送风参数影响研究

实验分析了送风温度、送风风速等参数对工位送风空调室内热环境的影响,得到了送风温度、送风速度对冷风感的影响规律:在一定范围内,送风速度越高、送风温差越大,冷风感不满意度越高.     

广东地区某建筑夏季室内热环境的CFD仿真评价

在暖通空调领域,计算流体动力学CFD（Computational Fluid Dynamics）方法常被用来求解气流及温度分布。本文利用CFD仿真软件对广东地区某一使用风机盘管的夏季空调建筑室内温度场、速度场进行模拟仿真,得出了夏季空调情况下该建筑的室内温度场和气流组织分布,结果分析表明,其室内平均温度及送风温差满足《公共建筑节能设计标准》广东省实施细则DBJ15—51—2007中的相关要求。     

送风速度对空调效果影响的数值研究

模拟了同侧上送下回空调房间在送风速度分别为v=1.3 m/s和v=2.6 m/s时,制冷及供暖工况下室内速度场和温度场的分布情况,分析了不同空调送风速度对室内参数的影响,以为工程设计和研究提供参考。     

Thermal performance of a personalized ventilation air terminal device at two different turbulence intensities

The performance of a circular perforated panel (CPP) air terminal device for a personalized ventilation (PV) system operating under two levels of turbulent intensity (Tu) was examined. The impact of Tu on spatial distribution of the cooling effect on the facial region and whole body were studied through experiments carried out in an indoor environment chamber using a breathing thermal manikin and 24 tropically acclimatized subjects. The PV system was adjusted to deliver treated outdoor air over a range of conditions, which were presented blind to the subjects in a balanced order. Over a 15-min exposure, subjects voted their thermal sensation experienced at the facial region and whole body. At each of the conditions, the near body flow field characteristics and heat loss rate on each of the 26 body segments of the manikin were measured. The results indicate that over the range of PV air supply volume studied, by controlling the temperature and velocity of PV air supply at 15 cm from the face, PV air supplied at lower Tu, when compared against that supplied at higher Tu:

• Achieved a larger range of velocities at the face.

• Achieved a greater cooling effect on the head region.

• Achieved a lower facial thermal sensation, which has potential draft risks (when facial_thermal sensation vote <−1).

Influence of air supply parameters on indoor air diffusion

This paper presents the field distributions of air velocity, temperature, contaminant concentration, and thermal comfort in an office with displacement ventilation for different air supply parameters such as the effective area, shape, and dimension of the diffuser and the turbulence intensity, flow rate, and temperature of the air supplied. The research is conducted numerically by using an airflow computer program based on a low-Reynolds-number k-ε model of turbulence. It can be concluded that the effective area, shape, and dimension of the diffuser and the turbulence intensity of the air supplied have little effect on the room air diffusion except at floor level. The influence of the flow rate and temperature of the air supplied is very significant on the air diffusion as well as on the thermal comfort and indoor air quality.     

地板送风不同送风温差对冷负荷减小系数的影响

利用数值模拟方法对不同送风温差下地板送风系统房间的总热源和单热源进行流场和温度场的模拟,分析了各单一热源冷负荷减小系数的变化规律,模拟结果表明在相同的送风速度下,除了放置于地面上的热源(主机)冷负荷减小系数基本维持在0.81,其它热源的冷负荷减小系数随着送风温差的增大而增大,且分层高度附近的热源冷负荷减小系数受送风温差的影响最大。     

Experimental parametric study of forced and mixed convection in a passenger aircraft cabin mock-up

Forced and mixed convection has been investigated experimentally in a full scale passenger aircraft cabin mock-up. The mock-up represents a generic cabin section of the A380 upper deck. Large scale particle image velocimetry (PIV) and temperature field measurements were conducted in a cross sectional plane of the cabin mock-up. The flow fields for two different air inlet configurations were measured and analysed under isothermal and cooling conditions. Furthermore the flow rates at the different air inlet positions were varied while keeping the air exchange rate constant. Our extensive experimental parametric study demonstrates that the flow field in aircraft cabins is affected by various fluid mechanical phenomena. Interaction between the supplied air jets, negative buoyancy forces acting on these air jets and interaction of thermal plumes with the supplied air jets, all influence the flow field inside the cabin. The impact of these effects differs considerably depending on the ventilation configuration and relative mass flow settings at the supply inlets.     

空调大温差研究(2):空调大温差送风系统设计方法

提出用定露点法计算常规空调大温差系统,逐项介绍了设计步骤;认为定露点法不但可以较准确地控制室内设计参数,掌握室内实际空气状态,而且可以利用计算机,使大温差送风的设计计算更加简捷、直观。强调采用定露点法计算时,单个系统不宜过大,热湿比不同的房间宜采用不同的空调系统,空调机组风量或风压较大时,宜采用风机压出式布置。     

地板辐射与置换通风空调系统运行参数

建立了基于EnergyPlus的地板辐射供冷加置换通风空调系统模型,模拟得到的室内温度和辐射地板所承担冷量与实验结果的误差小于±7%。在此模型基础上,改变送风参数和供水参数,得到置换通风供冷量、辐射地板供冷量、地板表面温度、室内空气平均温度、AUST温度等参数的变化规律。结合热舒适性模型,得到满足室内热舒适性(-0.5≤PMV≤0.5)条件下,置换通风的送风参数和辐射地板的供水参数范围,为复合系统设计和应用提供依据。     

CFD study of the thermal environment in an air-conditioned train station building

This study used the computational fluid dynamics (CFD) method to evaluate the indoor thermal environment of an air-conditioned train station building under three types of air-conditioning design schemes. The impacts of air-conditioning design parameters such as supply air temperature, velocity, altitude and angle of incidence were also investigated. The numerical results showed that if the waiting hall and entrance hall of the train station building were connected to each other and served with the cooling air respectively, when the cooling loads in the two halls were fixed and air-conditioning systems were designed properly, altering largely the cooling air supply scheme in the waiting hall while keeping the cooling air supply scheme in the entrance hall unchanged would have significant effects on the air distribution and thermal comfort in the occupied region of the waiting hall but may have some minor effects on those in the occupied region of the entrance hall. The uniformities of velocity and temperature distributions in the occupied region of waiting hall were satisfactory when side supply scheme was applied. Changing supply air temperature, velocity, altitude and angle of incidence would yield great effects on the thermal environment in the train station building. For the stratified air-conditioning design in the train station building, in order to obtain the satisfactory thermal comfort in the occupied region, the mid-height of the building was found to be a good position for the cooling air supply and the supply angle of 0° from the horizontal could be recommendable. The results also indicated that analyzing the effects of air-conditioning design parameters on the building environment with CFD was an effective method to find the way to optimize the air-conditioning design scheme.     

On underfloor air-conditioning of a room containing a distributed heat source and a localised heat source

This paper studies air flow in an air-conditioned room containing a distributed heat source and a localised heat source, into which cool air is supplied at low momentum through openings at a low level, and from which old air is extracted from a high level. This situation may be analogous to an auditorium containing a distributed audience and a localised group of actors and lighting on a stage, into which cool air is distributed from underneath the seating, and from which old air is removed through a ceiling, for example. Using a combination of a theoretical model and laboratory experiments, the paper shows that, in such conditions, if the localised heating is sufficiently strong compared to the distributed heating, the room will become stratified into two layers at steady state. A layer of warm air lies atop a cooler layer that attains a temperature above that of the supply air. This temperature structure depends primarily on the supply air flow rate and the ratio of the distributed heating to the total heat flux. For a room with fixed heating, increasing the supply air flow rate raises the interface between the upper and lower layers, while cooling both layers. The temperature in the upper layer depends on the total heat flux, but the temperature in the lower layer depends on the flux of distributed heating. For a room with a fixed supply air flow rate and a fixed total heat flux, increasing the strength of distributed heating warms the lower layer, but does not affect the temperature in the upper layer. Such increase in the strength of distributed heating also raises the interface. To achieve sufficient ventilation and thermal comfort in an occupied lower zone while keeping any pocket of uncomfortably warm air well above it, cool air needs to be supplied within an appropriate range of flow rates, which depends on the ratio of the distributed heating to the total heat flux. The paper shows how to determine such appropriate ranges of flow rates for different heating ratios, using the model.     

不同制冷量空调器在住宅中应用的实测对比研究

通过实验测试对比了不同制冷量的定速房间空调器用于住宅卧室中时的室内温湿环境状况和空调器的耗电量情况。实验结果表明,当空调器容量过大时,空调器的除湿能力下降,室内相对湿度偏高,空调器耗电量大,实验日条件下,使用1.5 HP空调器时的室内相对湿度比使用1 HP空调器的室内相对湿度高5%,而1 HP空调器耗电量比1.5 HP空调器减少12.7%。     

数据机房用分离式热管散热器运行特性分析

信息化水平的不断提高直接带来了数据中心耗电量的急剧增加。数据机房不同于一般的公共建筑,考虑到隔热、隔湿及洁净度的要求,即使在冬季也需供冷降温。而在满足散热需求的前提下,最大限度利用自然冷源则是降低空调能耗的最有效方法。但目前自然冷源的利用中常出现受环境影响大、节能效率低等问题,热管式散热器能将室内外空气完全隔绝,具有启动温差小、体积小、安装灵活等优点,在机房节能中有很大的应用潜力。以节能和良好的环境适应性为目标,对数据机房应用分离式热管的被动式散热方式进行了理论分析。以本学科工程领域现有技术为基础,理论分析了应用分离式热管的意义及优势,定义了分离式热管蒸发段及冷凝段的换热效率,建立了数据机房应用分离式热管散热系统的理论分析模型,以某名义排热量为30 kW的管翅式换热器为例,研究换热效率随风量的变化关系,得出分离式热管散热下可运行的最高允许室外温度、全年运行时间、功耗及全年节电量等关键参数。以某一30 kW冷负荷数据机房为模型进行CFD软件模拟,获得了采用分离式热管散热器的机房内部温度场分布,并与普通空调进行了比较。针对室外温度下降所引起的室内侧送风温度过低问题,提出减小室外侧风量的具体改进措施。利用理论模型设计分离式热管换热系统蒸发段和冷凝段,提出可根据热负荷及实际机房灵活配置,建设成本低,有效适应机房现有散热系统的方法。主要结论如下:(1)分离式热管散热器应用于数据机房散热,换热效率随着风量增加而减小,分离式热管散热器应用于数据机房散热,换热效率随着风量增加而减小,但可利用室外冷源的温度升高,可利用室外冷源的时间也随之增加,可根据换热器及所在地区设计最佳风量。(2)分离式热管散热下风量较大时,机柜进风温度比普通空调散热更为均匀,机房内热环境更好,可减少机房内局部热点。(3)若风量不变,分离式热管散热器蒸发段送风温度随室外温度降低,并有可能低于机房送风的标准温度。可通过减小室外侧风量使室内蒸发段出风温度满足数据机房送风温度,同时散热器的能效也可进一步提高。