Comparative thermal performance of new and old houses

The commitment to reduce energy consumption in buildings has focused attention on improving thermal insulation by employing measures such as the use of insulated cavity walls, double glazed sealed windows and insulated lofts. The energy consumption and thermal performance of two different types of house, an old and a new detached house are compared. Attention was focused on the living areas. The rate of air in-flow as determined by tracer gas, the air velocity and temperature distribution at two levels of 0.15 and 1.2 m were measured. The results show that in the new house the temperature difference between a seated person's head and ankle is more than 3 °C. This difference is increased when the central heating is switched on. In both houses the gap under the entrance door is large and contributes to a high internal air velocity. Despite the inadequacy of the installed air ventilator, the energy efficiency of the new house is demonstrated.     

The effects of ventilation systems and building fabric on the stability of indoor temperature and humidity in Finnish detached houses

Interest in finding out passive ways to keep the variation in the indoor climate within the comfort zone is gaining in popularity. One possible solution is the use of the moisture-buffering property of materials. In this study, the effects of the ventilation system and moisture-buffering properties of the building fabric on the stability of the indoor temperature and humidity are analysed by means of long-term field measurements. Indoor climate measurements were carried out in 170 detached houses (248 rooms). Temperature and relative humidity were measured continuously in bedrooms and living rooms at one-hour intervals over a one-year period. In general, it may be concluded that in this study, the ventilation had a greater effect on the indoor climate than the properties of the building fabric. The dampening effect of hygroscopic materials was remarkably less in the field measurements than it was in simulations in different studies. This indicates that completely non-hygroscopic and fully hygroscopic houses do not exist in reality. The hygroscopic mass of furniture, textiles, etc. is probably a factor that plays a significant role in indoor humidity, as do real air change rates, including window airing. Simulation tools need to be modified in order to be able also to handle furniture, textiles, and books, etc.     

Impact of Temperature and Humidity on the Perception of Indoor Air Quality

Abstract Sensory responses to clean air and air polluted by five building materials under different combinations of temperature and humidity in the ranges 18-28°C and 30-70%RH were studied in the laboratory. A specially designed test system was built and a set of experiments was designed to observe separately the impact of temperature and humidity on the perception of air quality/odour intensity, and on the emission of pollutants from the materials. This paper reports on the impact on perception. The odour intensity of air did not change significantly with temperature and humidity; however, a strong and significant impact of temperature and humidity on the perception of air quality was found. The air was perceived as less acceptable with increasing temperature and humidity. This impact decreased with an increasing level of air pollution. Significant linear correlations were found between acceptability and enthalpy of the air at all pollution levels tested, and a linear model was established to describe the dependence of perceived air quality on temperature and humidity at different pollution levels.     

太阳辐射引起建筑群温升的探讨

介绍了建筑群温度变化的数学模型,模拟了济南某小区在四种不同工况下太阳辐射引起的建筑群的温升情况,比较了建筑密度、下垫面材料、风速对建筑群温升的影响,结果表明,改变下垫面材料和增强自然通风可改善城市热岛效应。     

冷凝式燃气热水器的腐蚀防护

分析了电化学腐蚀的机理以及冷凝水的pH值、温度、溶存氧和溶解盐等因素对冷凝式燃气热水器腐蚀的影响,探讨了冷凝式燃气热水器腐蚀防护的措施。提出以天然气作为气源,材料进行化学镀处理,采用分离倒置式换热器可减少冷凝区域酸性腐蚀。     

Material emission rates: Literature review,and the impact of indoor air temperature and relative humidity

An extensive literature review of research on the impact of indoor air conditions; temperature, relative humidity and surface air velocity on materials emission rates is presented. This paper also presents the results of an experimental work to study the impact of room air temperature and relative humidity on materials emission rates. The results indicate that both the temperature and relative humidity have a significant effect on the emissions from paint and varnish. In the case of varnish, the results were consistent with earlier results. However, the paint results show inconsistent emission behaviour. Further, for both materials, the individual compounds did not necessarily follow the same trend established for the TVOC.     

Impact of Temperature and Humidity on Chemical and Sensory Emissions from Building Materials

Abstract The chemical and sensory emissions from five building materials (carpet, polyvinyl chloride (PVC) flooring, sealant, floor varnish and wall paint) were tested under different combinations of temperature and relative humidity in the ranges 18–28°C and 30–70% relative humidity (RH). The experiment was performed in a climate chamber where a specially designed test system was built to study emissions from the five materials. The test system could provide different temperatures and humidities of air around the materials, while the air, after being polluted by the emissions from the materials, could be reconditioned to 23°C and 50% RH for sensory assessments. The experiment was designed to separate the direct impact of temperature and humidity on perception from the impact on sensory emission. The study found little influence of temperature on the emissions from the five materials whether expressed in chemical or sensory terms. The effect of humidity was found to be significant only for the waterborne materials – floor varnish and wall paint. Compared with the direct impact of temperature and humidity on the perception of air quality, the impact of temperature and humidity on sensory emissions from the building materials has a secondary influence on perceived air quality.     

活性碳纤维脱除空气中二氧化硫的研究与应用

本文采用四氯汞盐溶液吸收——盐酸副玫瑰苯氨比色法研究了活性碳纤维材料(ACF)对微量二氧化硫等气体的吸附性能。空气通过ACF材料后，二氧化硫的脱除率在46％以上。将其应用于家用恒温换气装置中，可有效脱除进入室内空气中的二氧化硫等有害气体，改善室内空气品质，保持室内空气清新、温度适宜。     

Airtightness and ventilation strategy in Japanese residences

In this paper, the relationship between airtightness and indoor air quality is shown, based on measurements made of thirteen detached wooden houses. Secondly, a chart for predicting air infiltration from airtightness rank is given, and the relationship between airtightness and air infiltration is discussed. Finally, optimum combinations of heating and ventilating systems and types of cooking appliances are suggested according to the airtightness rank of a house.     

Air tightness and air leakages of new lightweight single-family detached houses in Estonia

A field measurement study of the air tightness and the air leakages of 32 detached houses was conducted during 2003–05 in Estonia. The buildings were classified according to the number of storeys, building technology, and the ventilation systems. Using the standardized BlowerDoor pressurization technique, the air leakage rate of each house was determined. To determine typical air leakage places and their distribution, an infrared image camera and a smoke detector were used.     

多孔材料污染物散发外部影响因素作用分析

基于所建的污染物散发模型,分析了室内温度、传质系数、换气次数对多孔材料污染物散发的影响。结果显示,室内温度对材料内污染物散发的影响非常明显,温度越高,污染物散发时间越短;提高传质系数不能显著加速污染物散发,而降低该值却可以抑制污染物的释放;换气次数对污染物散发影响很小,但可以通过改变换气次数来控制室内污染物浓度。     

某住宅室内装修污染物分析与控制

对当前室内装修所用到的装修材料进行了介绍,分析了室内装修材料带来的室内污染物和对人体的危害。以一套经过新装修的住宅为例,主要对卧室内的污染物种类与含量进行了测量,给出室内污染物浓度随着时间的变化情况,测量发现室内主要污染物甲醛的浓度受温度、相对湿度、天气状况等影响。针对室内污染物的散发特点与分布,合理的对装饰装修引起的室内空气污染进行控制。     

基于原材料温度的混凝土入模温控研究

混凝土入模温度的控制是工程上减少温度裂缝的有效措施。文章考虑了原材料比热容的差异,分析了大气温度及各种原材料温度对混凝土入模温度的影响;根据入模温度的控制要求,通过分析计算,提出了基于原材料温度的入模温度控制的必要技术措施,合理地确定原材料温度点,并在泰州大桥工程进行了应用,为实际环境中原材料初始温度调控给出了借鉴和参考。     

The influence of the concealed pollution sources upon the indoor air quality in houses

This report presents the results of investigations on the indoor air quality of common Japanese detached houses. It is necessary to control the emission rates from the interior materials and the ventilation rates to keep indoor concentration of VOC enough low. And it is also necessary to consider the influence of the pollution sources in the concealed spaces for better indoor air quality in some kinds of building structures and some kinds of ventilation systems. In this study the influences of the concealed pollution sources upon the indoor concentrations of pollutants were investigated using three detached houses with four ventilation systems and the following results were obtained. When the ventilation system was changed from the air-supply type to the air-exhaust type, the indoor concentrations of formaldehyde increased. The infiltration ratios: the ratios of the infiltration rate to the indoor space toward the emission rate of a pollutant in the concealed space were measured using the tracer-gas method. The ratios from the beam spaces and the partition were about 100% in most cases. The ratios from the crawl space under the first floor and the truss space under the roof were lower than those from the beam space and partitions in most cases, because those spaces have ventilation openings. But the ratio from the crawl space reached about 100% in the house without ventilation openings at the crawl space. And even in the house with ventilation openings at crawl space, the ratio reached 50% in the house with the exhaust-ventilation system. Therefore, it became clear that the use of the medicine to prevent the deterioration of the wooden structure and the white ants in the crawl spaces must be limited. The ratio from the envelope wall was changed with the pressure difference between inside and outside. These results showed that it is necessary to prevent infiltration from the concealed spaces and to control the emission rate from the concealed pollution sources.     

几种建筑外墙隔热性能的比较分析

建立了几种建筑外墙结构的数学模型,结合南京夏季室外综合温度,采用FLUENT软件对几种墙体的热工性能进行对比,并从传热学的角度对墙体的内部传热机理进行分析。研究结果表明：添加保温材料或者空气问层均能够提高墙体的隔热性能;墙体采用外保温时,其保温层较高的热阻使热量集中墙体外表面,减小向室内侧的传热量,同时也提高了墙体的耐久性;通过对比几种具有不同隔热措施的建筑墙体,外保温墙体对温度波的衰减度最大,内壁面温度的波动幅度最小,抵御室外温度影响的能力强,热稳定性能好。     

蓄热、通风复合墙体应用研究

文章介绍的复合蓄热、通风墙体建筑,主要测试了复合墙体冬季利用太阳能加热墙体内空气及相变材料对室温的影响,以及夏季尝试地埋管冷空气降低墙体温度,避免墙体向室内传热来降低整个建筑的空调负荷.     

Exploration of the relationship between water main breaks and temperature covariates

Water utilities (especially in colder climates) often experience an increase in water main breaks in colder seasons. Some observers argue that this increase largely occurs during the period when there are sudden and prolonged changes in water and air temperatures, which typically occur during the late fall to early winter (temperature drop) and late winter to early spring periods (temperature rise). This paper examines the impact of temperature changes on observed pipe breakage rate for three pipe materials, namely, cast iron, ductile iron and galvanised steel. Several water and air temperature-based covariates were tested in conjunction with a non-homogeneous Poisson pipe break model to assess their impact on water main breaks, using data sets from three different water utilities in the USA and Canada. Temperature-based covariates, such as average mean air temperature, maximum air temperature increase and decrease, and how fast the air temperature increase and decrease over a specific period of days, were found to be consistently significant. While the availability of water temperature data (which most utilities do not have) can enhanced the prediction of water main breaks, it appears that air temperature data alone (which most utilities can access) are usually sufficient.     

Modeling of phase change material peak load shifting

This paper addresses potential peak air conditioning load shifting strategies using encapsulated phase change materials. The materials being considered here are designed to be installed within the ceiling or wall insulation to assist in delaying the peak air conditioning demand times until later in the evening. To assist in understanding the behavior of this material, an idealized model has been developed which uses the one-dimensional diffusion equation driven by time varying temperature functions imposed at the boundaries. In developing the model, the phase change temperature is a critical parameter, as is the latent heat of melting. These variables are treated parametrically. Other variables such as the characteristic ambient temperature variations and the thermostat set point are varied relative to the phase change temperature. Comparisons are made to the temporal variations of the heat flows without the application of the phase change material to those with the phase change material.     

调湿材料吸放湿性能的测试方法

建立了调湿材料吸放湿过程的热湿传递耦合方程,在周期性热湿作用边界条件下对耦合方程进行变换分析,得出其理论解。研究了封闭空间内调湿材料在周期性热湿作用下的吸放湿特性,结果表明空气含湿量波动振幅与温度波动振幅之比值为一复常数,其模值能表示材料吸放湿能力大小,初相位能表示材料吸放湿应答性快慢,从而引出了测试调湿材料吸放湿性能的方法———封闭箱热作用法。利用该方法测试了硅胶板、混凝土板和夯土板的吸放湿性能,验证了该方法的有效性,结果显示硅胶板的吸放湿性能最好,混凝土板最差;得出了调湿材料在封闭箱中的吸放湿规律,即空气温度升高时材料放湿,空气温度下降时材料吸湿,可根据空气绝对湿度曲线判断材料吸放湿性能的好坏。     

Subjective Indoor Air Quality in Schools – The Influence of High Room Temperature,Carpeting, Fleecy Wall Materials and Volatile Organic Compounds (VOC)

There is a growing concern about indoor air quality (IAQ) in schools. We have studied relations between subjective indoor air quality (SIAQ) and measured IAQ among school personnel (N = 97) in six mid-Swedish primary schools. Information on SIAQ and the psychosocial work environment was measured by a self-administered questionnaire, using analogue rating scales. Indoor exposures were quantified by hygienic measurements. Perception of high room temperature was related to a poor climate of cooperation, fleecy wall materials, and the concentration of volatile organic compounds (VOC), including xylene, limonene, and butanols. Perception of air dry-ness was related to atopy, work stress, poor climate of cooperation, high room temperature, low air humidity, and high VOC concentration, including, limonene, and n-alkanes. Perception of dusty air was related to work stress, the role of schoolteacher, and exposure to 2-ethyl-1-hexanol. No relations were found between SIAQ and CO2, building age, or respirable dust. To achieve a good SIAQ, room temperature should be kept at a maximum of 22°C, and exposure to VOCs and fleecy materials should be minimized. Finally, a sound psychosocial work climate is essential for the perception of a good physical indoor climate.