家用水冷空调器与风冷空调器运行性能比较

本文旨在探讨水冷空调器在住宅中使用的节能潜力。设计了分体式风冷和水冷空调器性能的测试实验台,实验研究在不同的室内负荷和室外干球温度、相对湿度条件下,水冷空调器与风冷空调器的性能和节能效果比较。     

家庭使用空调机应注意的几个问题

一、选购空调器需要考虑的几点 1.制冷量:空调器制冷量应大于或等于空调房间所计算出的总耗冷量,同时注意空调房间与空调器二者的负荷工况应相近,否则在空调温度湿度上会产生较大偏差。空调器的制冷量工况是:室内于球温度为27℃,湿球温度为19.5℃;室外干球温度为35℃,湿球温度为24℃。如果冷凝器采用水冷却,则进水温度应为28℃。 2.电源:用户电源应与空调器的使用电源相一致,否则会烧坏电机或出故障。 3.噪声:选购空调器,噪声目前要求在60dB以下。 4.耗电量:从家用空调器来说,用电量极为重     

夏季空调室外计算参数的修正研究

本文对5个典型城市建筑在"干湿球温度分别统计,干球温度为基础耦合同期湿球温度,湿球温度为基础耦合同期干球温度,干湿球温度之和与湿球温度分别统计"四种参数选取方法条件下的空调设计负荷及典型气象年夏季逐时冷负荷分别进行计算,以最大逐时冷负荷为指标,获得该地区适用的空调室外设计参数,进而对干、湿球温度分别统计所得的参数做出修正。结果表明,计算湿球温度的变化对空调设计负荷的影响较大。"干球为基准耦合湿球温度"的参数选取方法适用于干空气能资源较丰富的地区,"湿球为基准耦合干球温度"的参数选取方法适用于干空气能资源较贫乏的地区,给出了五个区域的室外计算参数修正系数。     

数码涡旋多联式空调系统冬季以空气源热泵制热运行的实验研究

实验研究了数码涡旋多联式空调系统冬季以空气源热泵制热运行时的运行特性,分析了室内设定温度一定时室外干球温度变化对室内机和系统的小时制热量、机组的小时耗功量及系统的小时供热性能系数HHPF的影响.     

闭式冷却塔冬季运行性能研究

以带填料的闭式冷却塔为分析对象,基于冷却塔热质交换原理及能量平衡方程,结合其热质交换数学模型以及各项冷却塔传热性能评价指标,以冷却塔额定工况的换热能力为比较基准,重点分析了冬季室外气象参数(干球温度、湿球温度)对冷却塔热湿交换性能的影响。在此基础上,进一步分析了闭式冷却塔在上海地区冬季运行的具体性能。     

蒸发冷却在我国不同区域地下工程中的适用性分析

以送风状态点的干球温度、湿球温度及含湿量为基准,建立了蒸发冷却适用区域的6区模型,并以室内状态点的上限值作为送风状态点,分别以夏季空调室外设计参数、地下工程夏季空调设计参数、夏季空调干球温度及不满足200 h含湿量作为室外状态设计参数,计算并分析了各种形式的蒸发冷却系统在我国不同区域地下工程中的适用性,为蒸发冷却在地下工程中的应用提供基本设计依据。     

不同饱和水汽压计算式对室外湿球温度计算的影响

通过试算法计算湿球温度,分别采用Goff-Cratch、Hyland-Wexler、Magnus-Teten、Murphy-Koop、改良Buck、Buck这6种饱和水汽压计算式来计算饱和水汽压。首先,利用干球温度范围为-15～40℃、相对湿度范围为5%～100%、大气压为1 01325 hPa共1 120组数据,对比6种饱和水汽压计算式下的计算湿球温度与查焓湿图得到的湿球温度,得出:相对湿度为5%、30%时,湿球温度的平均误差最大相差001℃;干球温度为-15～0℃时,湿球温度的平均误差最大相差001℃;整体来看,平均误差均为059℃,均方根误差均为102℃;然后,利用人工观测的干球温度、相对湿度以及大气压,对比6种饱和水汽压计算式下的计算湿球温度与人工观测湿球温度,得出:6种饱和水汽压计算式下的计算湿球温度均相等,且具有相同的误差。最后,综合两者对比结果,得出:在误差不超过001℃的精度下,可认为6种饱和水汽压计算式对室外湿球温度的计算没有影响;在室外湿球温度的计算中,可选择6种饱和水汽压计算式之一来进行饱和水汽压的计算。     

夏季湿球温度日变化规律的探讨

在目前使用的冷负荷计算方法中 ,冷负荷都是采用以“计算日”为周期的时变量来表达以适应相同时刻冷负荷叠加的需要。然而新风冷负荷的计算例外 ,至今仍是按常量取值 ,不能不令人遗憾。其实 ,在清华大学、同济大学等四校合编的高等学校教材《空气调节》中已编入了一幅气温日变化曲线图 ,其中包括了室外湿度日变化曲线、室外干球温度日变化曲线和室外相对湿度日变化曲线。从图中可悟出以下几点结论 :①湿球温度是个时变量 ,其图形可视为以日为周期近似余弦波的曲线。②湿球温度与干球温度在一天中各有一个峰、谷值 ,不同点在于峰、谷值出现的…     

室内湿度对多联机空调性能的影响研究

通过运用焓差试验室对某品牌多联机空调机组进行试验,测试在相同室外温度、相同室内干球温度、不同室内湿球温度下多联机空调机组的各种性能参数变化情况,并且对其制冷量、能效、耗功、潜热显热量、潜热显热比、除湿量等进行了对比分析.试验结果表明:室内温度相同的情况下,室内相对湿度从35%增加到75%,机组制冷量增加了21.02%,耗功量增加了6.23%,能效增加了13.97%;当室内相对湿度小于35%的时候,机组能力全部靠显热来提供;在湿度较高和较低的情况下可以通过改变系统的控制方式来改变压缩机的运行频率,降低功耗,实现节能.     

冷却水系统变流量运行的控制与分析

冷却水泵变流量运行需考虑空调负荷分布与室外湿球温度分布的影响。通过综合考虑冷却水变流量运行对冷却水泵和冷水机组能耗的影响,对比分析不同控制策略下冷却水系统的节能效果,提出了直接利用室外湿球温度控制冷却水系统定变流量运行的控制策略,并给出相应的控制流程。     

关于夏季空气调节室外空气计算参数的讨论

根据我国室外气象数据,比较了由历年平均不保证50h干、湿球温度计算得到的含湿量与根据气象数据历年平均不保证50h统计得到的含湿量的差异。考虑到室外气候条件对建筑热环境和不同设备空气热湿处理过程的影响,建议在空调设计中根据影响因素不同选取相应的室外空气设计参数。采用国家气象局1971—2003年的气象数据,得到全国31个主要城市分别以空气干、湿球温度和露点温度为主的3种设计指标。     

叉流平板式间接蒸发冷却过程数值模拟

建立了数学模型,对叉流平板式间接蒸发冷却过程进行了数值模拟分析,得到了分别沿一、二次空气流动方向一次空气干球温度和二次空气干湿球温度的分布,以及水膜温度的变化情况。     

Performance calculations of residential cooling systems for simplified energy analysis

The seasonal performance of space cooling systems generally depends on indoor and outdoor temperatures and humidities and on the ratio between actual cooling loads and cooling equipment size. In principle, any given weather condition and desired indoor dry-bulb temperature calls for an interactive application of psychrometrics and equipment performance curves until satisfactory indoor conditions are derived for which both sensible and latent cooling loads equal sensible and latent heat removal rates. This paper presents a simplified approach that derives the indoor wet-bulb temperature in close form for both cases when the cooling system condenses water from the space and when it does not. This approach relies on a local linearization of the psychrometric chart in the region of interest for indoor comfort conditions. Performance curves for total and sensible capacity and for the electric power input were derived for several different residential air-to-air reciprocating compressive cooling systems. The performance curves are empirical fits to manufacturer's data or to laboratory results. The predictions of the simplified method were compared with DOE-2 when calculating space cooling consumption for a residence in both a hot arid and in a hot humid climate. The comparison showed excellent agreement both for hour-by-hour calculations and for monthly calculation of this method are sufficiently simple to be applicable to micro-computers and pocket calculators.     

掘进工作面降温参数拟合分析

为了掌握矿井掘进工作面降温参数变化规律,更好的指导现场实施与应用,以存在高温热害现象的长距离掘进巷道(掘进巷道长度1 000 m)为研究对象,现场实际测定矿井降温系统运行后部分测点风流温度,拟合分析得到了部分参数之间较准确的定量关系。拟合结果表明:赵楼煤矿掘进工作面迎头温度与风筒出口风流温度(干、湿球温度)近似呈线性关系;与空冷器后处理风流温度(干球温度,相对湿度近似为100%)在一定范围内近似呈二次抛物线关系。此外,掘进工作面附近干湿球温度差值较大,最大可达5~7 ℃。风流在回头过程中热湿交换严重,很容易形成放大的回头增热、增湿现象。     

如何确定发电机房通风降温时的室外计算温度

按一般设计理念,关于室外计算温度的确定原则,如进行空调设计时,采用空气调节室外计算干球温度;如进行通风设计时,采用通风室外计算温度;如进行采暖设计时,采用采暖室外计算温度.不同目的设计形式,采用不同的室外计算参数.但是,对于常年全负荷运行的发电设备而言,如果机房内是采用通风换气降温时,不能错误的采用夏季室外通风计算温度...     

太原市某办公建筑自然通风潜力的预测

以太原市典型气候年（MTY2）的月逐时平均干球温度为依据,采用度时法,预测了太原市典型气候年的某办公建筑的自然通风潜力,最后指出在建筑的几何尺寸和风口大小确定的情况下,自然通风的潜力强烈受到室外气候、室内余热量的影响。     

Outdoor design conditions for HVAC system design and energy estimation for buildings in Hong Kong

Outdoor design conditions are important for heating, ventilating and air-conditioning (HVAC) system design and energy estimation for buildings. A research study on the determination of outdoor design conditions for HVAC applications in Hong Kong is presented here. Methods for determining outdoor design conditions are examined and the existing data for Hong Kong are studied. New design data developed from the latest weather database compiled for Hong Kong are provided. The characteristics of the Hong Kong climate are studied from the 33-year long-term statistical distributions of its hourly dry-bulb and wet-bulb temperatures. Significance, properties and proper selection of outdoor design conditions for HVAC design are then discussed. It is hoped that designers can assess critically the outdoor design conditions they have taken for granted for their building design and evaluate suitable data for design weather based on their applications and risk levels.     

Rational selection of near-extreme coincident weather data with solar irradiation for risk-based air-conditioning design

The selection of design solar irradiance in the current ASHRAE and CIBSE design handbooks is independent on design dry-bulb and wet-bulb temperatures. The probability that the load would not exceed the system capacity determined on this basis may not match the reliability level that the design weather data were meant to safeguard. Hence, a statistic method was developed for the rational selection of coincident solar irradiance, dry-bulb and wet-bulb temperatures. The new method combines, based on the principle of heat transfer, the three weather parameters and building characteristics into a single impact factor, which may be called as equivalent temperature. This ensures that the joint probability of occurrence of the three coincident weather parameters can match the capacity reliability level of air-conditioning systems, which may be required by building owners. The method was applied to historic weather records of 25 years in Hong Kong to generate coincident design weather data. These new design weather data were compared with those design weather data produced by the traditional method. Results show that traditional design solar irradiance, dry-bulb and wet-bulb temperatures may be significantly overestimated in many conditions. Moreover, the new method allows HVAC engineers to determine the peak cooling load directly without the need for calculating 24 h cooling loads on one design day for every month of the year. This greatly simplifies the design cooling load calculation. Although the new design weather data are only for buildings whose thermal lag is less than 1 h, the method provides a basis for further generating design weather data for buildings with a large thermal lag.     

变流量冷冻水系统温差控制法的适用性

研究了末端设置通断控制阀的一次泵变流量系统在温差控制下的水力特性,并结合风机盘管与房间的非线性换热耦合特性,进一步探讨了温差控制的适用条件以及变温差控制温差值的设定方法。结果表明：末端设置通断控制阀的系统,当管网整体负荷分布均匀且各开启用户的负荷变化规律相近时,温差控制同样是较为适用的,此时系统的水力失调对室内温湿度的影响较小;采用变温差控制时,仅以不同的总负荷率分段设置温差值,并不能获得良好的室内温湿度控制效果,建议以优先保证风盘除湿能力和室内干球温度为原则设定温差值,相比于目前的方法,在同等的室内相对湿度波动下,室内温度的稳定性可以得到保证。     

Overheating and passive habitability: indoor health and heat indices

As extreme heat and weather events are predicted to increase due to global warming, the risk of human heat stress within buildings will increase. To be resilient, buildings will need the capacity to provide habitable indoor conditions without power for limited amounts of time. Additional indoor thermal standards are required for public health to address ‘passive habitability’ during power outages. Current research on building-related heat stress and numerous heat indices is examined in relation to the development of a new heat-safety metric for use in passively conditioned buildings. Most indoor overheating research relies on outdoor temperature data and has no common indoor heat index for evaluating indoor heat stress. A recommendation is made for using the wet-bulb globe temperature (WBGT) and predicted heat strain (PHS) indices for modelling and monitoring of indoor heat stress in healthy adult populations because both indices utilize the primary thermoregulation variables, have associated heat-stress thresholds, and can be assessed or tracked with existing environmental monitoring methods and predictive energy modelling techniques. Further research is recommended on health effects and exposure limits of vulnerable populations, and the variation in thermal factors within buildings and the building stock.