Conditioning strategies of indoor thermal environment in warm climates

Commenting on some negative effects of traditional conditioning strategies of indoor thermal environment in warm climates, the authors present a fundamental concept of thermal comfort and acceptability, new air-conditioning strategies by using fluctuating air movement based on the findings of human responses to transient thermal environment, and a prediction of energy saving caused by elevated indoor temperature settings. In addition, how to meet the requirement of providing human-beings a healthy, comfortable and affordable indoor air temperature, and to achieve a goal of sustainable development are also discussed in this paper.     

Extension of the PMV model to non-air-conditioned buildings in warm climates

The PMV model agrees well with high-quality field studies in buildings with HVAC systems, situated in cold, temperate and warm climates, studied during both summer and winter. In non-air-conditioned buildings in warm climates, occupants may sense the warmth as being less severe than the PMV predicts. The main reason is low expectations, but a metabolic rate that is estimated too high can also contribute to explaining the difference. An extension of the PMV model that includes an expectancy factor is introduced for use in non-air-conditioned buildings in warm climates. The extended PMV model agrees well with quality field studies in non-air-conditioned buildings of three continents.     

A study of the effectiveness of different control strategies in double skin facades in warm and humid climates

Thermal building simulations were linked to nodal airflow network simulations for a detailed ventilated facade calculation of performance.The validated simulation model can be used to optimize airflow window design in respect to reducing the solar heat gains during the summer period by controlling the exhaust airflow. This may result in significant energy savings and a reduction in systems cooling size. This work evaluates different control strategies of internally ventilated facade designs in respect to energy consumption savings. It further proposes a new type of airflow window to control the exhaust airflow that can help to reduce cooling load of an office up to almost 40%. An important factor was the development of a climate sensitive regulator that helps to take advantage of the hot and humid climate.     

Adaptive temperature limits for air-conditioned museums in temperate climates

Indoor temperature (T) and relative humidity (RH) are important for collection preservation and thermal comfort in museums. In the 20th century, the notion evolved that T and RH need to be stringently controlled, often resulting in excessive energy consumption. However, recent studies have shown that controlled fluctuations are permissible, enabling improved energy efficiency. Consequently, the thermal comfort requirements are increasingly important to determine temperature limits, but knowledge is limited. Therefore, a thermal comfort survey study and indoor measurements were conducted at Hermitage Amsterdam museum in Amsterdam, the Netherlands for one year, including: (1) monitoring of existing conditions (T?=?21°C, RH?=?50%); and (2) an intervention in which T is controlled based on an adaptive comfort approach (T?=?19.5–24°C, RH?=?50%). The results show that the thermal comfort of the existing conditions is far from optimum; visitors feel too cool in summer and slightly too warm in winter. The adaptive temperature limits were developed to improve thermal comfort significantly without endangering the collection, thereby saving energy. Furthermore, facilitating visitors to adapt their clothing may contribute to enlarging the temperature bandwidth and improve (individual) thermal comfort.     

散热器与低温热水地板辐射供暖系统的比较

通过对散热器采暖系统和地板采暖系统的特点进行比较，分析得出散热器系统虽然传统，但是不会被地板采暖系统所替代，两种系统各有优劣，在进行设计时，需要根据建筑功能和城市气候特点进行采暖系统的合理选择。     

The association between arsenic exposure from drinking water and cerebrovascular disease mortality in Taiwan

Background

Chronic arsenic exposure is associated with a variety of diseases, including cancer, peripheral vascular disease, and diabetes. However, its association with cerebrovascular diseases (CVD) has not yet been resolved. The aim of this study is to explore this association in Taiwan using nation-wide data.

Materials and methods

We analyzed mortality data in Taiwan from 1971 to 2005 and choose two geographic areas with populations suffering from chronic exposure to arsenic in drinking water for study, the blackfoot disease endemic area (BFDEA) in the southwest and Lan-Yang Basin (LYB) in the northeast parts of Taiwan. The Chia-Yi and Tainan Counties, which surround the BFDEA, and the nation of Taiwan as a whole were used as reference populations. Direct standardized mortality rates and gender-specific indirect standardized mortality ratios (SMRs) were calculated for the four populations.

Results

The direct standardized mortality rate for CVD in Taiwan decreased from 2.46/10³ person-year in 1971 to 0.63/10³ person-year in 2005, and women had significantly lower mortality than men (SMR = 0.80; p < 0.05). The CVD mortality rates of populations with chronic arsenic exposure were significantly higher than the reference populations (SMR ranging from 1.06 to 1.09 in men and 1.12 to 1.14 in women; p < 0.05). The BFDEA had higher CVD mortality rates than the LYB, with SMR = 1.05 (p < 0.05) in men and SMR = 1.04 (p = 0.05) in women.

Conclusion

In Taiwan, while CVD mortality decreased in both genders between 1971 and 2005, chronic arsenic exposure from drinking water was associated with increased risks of CVD.     

A vulnerability study of the low-income elderly in the context of high temperature and mortality in Seoul, Korea

INTRODUCTION: We investigated the impact of environmental high temperature on mortality in Seoul, Korea, and the consequences of high temperature-induced mortality with a focus on the low-income elderly. METHODS: Changes in the risk of death by age and income were estimated by a 1 degrees C increase in temperature using a generalized additive model adjusting for non-temperature related factors: time trends, seasonality, and air pollution. The study covered the years of 2000, 2001, and 2002. RESULTS: We found that income and age were potential factors in high-temperature-induced excess mortality. Evidences to support these results are as follows: first, regarding the effect of an economic factor in the association between mortality and high temperature, the study shows that the mortality rate of the low-income group is higher, by as much as 1.3- to 1.7-fold, than that of the general population. Second, taking age into consideration, the mortality of low-income elderly people is 1.5-fold higher than that of the whole low-income group. The combined effect of income and age on mortality is estimated as 2.3-fold higher than that of the general population. But the results of the low-income and elderly group were not statistically significant due to wide standard deviation. CONCLUSIONS: The relationship between high-temperature-induced excess mortality, income, and age suggests the need for a public health message, yet many results were not statistically significant: preventive and health care interventions need to be administered to the elderly and low-income group during periods of high temperature.     

Distributed lag effects in the relationship between temperature and mortality in three major cities in South Korea

In many cases, the effect of an environmental exposure event is not restricted to the period when it occurs. Understanding the extent to which high-temperature exposure hastens the occurrence of health outcomes is a key to interpreting public health risks correctly and developing appropriate intervention programs related to heat. We explored distributed lag effects in the relationship between high temperature and mortality in summer (June-August) in Seoul, Daegu, and Incheon, South Korea, from 1991 to 2008.A Poisson regression model adapted for time-series data was used to estimate short-term heat-related mortality impacts. To examine the distributed lag effects, we fitted a constrained distributed lag model that included lagged exposure variables as covariates, applying a function of days of lag according to B-spline bases.The effects on mortality caused by high-temperature exposure continued for about 5 days, and slight deficit effects after the initial mortality increases were observed, even if not initially apparent. Thirty days after high-temperature exposure, the cumulative effects were still high in Seoul and Incheon.This study shows a pattern of distributed lag effects of high-temperature exposure that the single-day model could not identify. Our results confirm that summer high temperature has an effect on mortality, not advancing the date of adverse events by a few days. Ultimately, it suggests that public health programs be amended to allow for differential high-temperature effects spread over multiple days.     

Correlating indoor and outdoor temperature and humidity in a sample of buildings in tropical climates

The incidence of several respiratory viral infections has been shown to be related to climate. Because humans spend most of their time indoors, measures of indoor climate, rather than outdoor climate, may be better predictors of disease incidence and transmission. Therefore, understanding the relationship between indoor and outdoor climate will help illuminate their influence on the seasonality of diseases caused by respiratory viruses. Indoor-outdoor relationships between temperature and humidity have been documented in temperate regions, but little information is available for tropical regions, where seasonal patterns of respiratory viral diseases differ. We have examined indoor-outdoor correlations of temperature, relative humidity (RH), and absolute humidity (AH) over a 1-year period in each of seven tropical cities. Across all cities, the average monthly indoor temperature was 25 ± 3°C (mean ± standard deviation) with a range of 20–30°C. The average monthly indoor RH was 66 ± 9% with a range of 50–78%, and the average monthly indoor AH was 15 ± 3 g/m³ with a range of 10–23 g/m³. Indoor AH and RH were linearly correlated with outdoor AH when the air conditioning (AC) was off, suggesting that outdoor AH may be a good proxy of indoor humidity in the absence of AC. All indoor measurements were more strongly correlated with outdoor measurements as distance from the equator increased. Such correlations were weaker during the wet season, especially when AC was in operation. These correlations will provide insight for assessing the seasonality of respiratory viral infections using outdoor climate data, which is more widely available than indoor data, even though transmission of these diseases mainly occurs indoors.     

浅谈大体积高性能混凝土施工中的温度控制

通过对大体积承台混凝土施工中温控措施的分析,说明在混凝土结构芯部埋设冷却管,采用循环水法可有效降低混凝土内部与表层、混凝土表层与环境之间的温度差,从而达到有效控制因温差原因产生的混凝土内部及表面收缩裂纹的目的。     

谈高温环境下混凝土施工技术

分析了高温对混凝土施工的不利影响,从原材料、配合比、环境温度等方面提出了高温环境下混凝土施工的具体措施,并对该条件下混凝土的养护提出了优化建议,以确保混凝土的施工质量。     

Optimization of indoor air temperature set-point for centralized air-conditioned spaces in subtropical climates

Current Building Management System (BMS) does not integrate well with real-time occupant response. In order to fine-tune the system to meet individual demands and to maximize the occupant acceptance of indoor thermal environment, a new notion of Bayesian control algorithm was developed in this study. Control parameters of a weighting function for air temperature control (namely, the control temperature constant k_T and the probable acceptance of the air temperature set-point λ) and two prior distribution functions of air temperature set-point, namely the uniform prior and the expert's prior, were examined. Optimum air temperature set-points of air-conditioning systems obtained from certain Hong Kong offices were then used to demonstrate the applicability of the new algorithm for controlling an example air temperature set-point ranged between 0.2 °C and 1 °C. This algorithm would be useful for adaptive thermal comfort control in a large, post-occupied air-conditioned space.     

火灾高温下GFRP筋和混凝土粘结性能试验研究

为了研究火灾环境中不同温度下纤维增强塑料(FRP)筋和混凝土之间粘结性能的变化以及火灾后FRP筋和混凝土之间的残余粘结性能,以玻璃纤维增强塑料(GFRP)筋为例,对34组共120个混凝土棱柱体粘结试件进行了火灾高温时GFRP筋和混凝土之间粘结性能的试验研究,试验主要考虑了温度、混凝土强度和粗骨料粒径的影响,得到了高温中和降温后GFRP筋和混凝土之间的粘结强度以及GFRP筋的锚固长度。试验结果表明,随温度的升高,粘结性能会随之下降,当温度下降至室温后,其粘结性能会得到恢复。这些试验结果可以应用于GFRP筋增强混凝土结构抗火设计中。     

高温后钢筋混凝土柱截面温度数值模拟与分析

利用有限元软件ANSYS对高温后钢筋混凝土柱作三维温度场的非线性分析,并对钢筋混凝土柱进行了实验室高温试验。通过在柱子内部埋置热电耦,获得了构件截面温度的分布规律。结果表明,数值模拟结果与试验结果吻合较好,说明采用ANSYS软件对钢筋混凝土柱的耐火性预测较准。     

Relationship between winter temperature and mortality in Seoul, South Korea, from 1994 to 2006

In South Korea, the mortality increases with temperature above a certain threshold during the warm season. In contrast, despite the common burden of cold weather, little is known about the effects of low temperatures on mortality. We evaluated the relationship between low temperatures and mortality in winter (December-February) in Seoul, South Korea, from 1994 to 2006. Data were obtained from government agencies. After adjusting for trends in time, day of the week, holidays, and relative humidity, we explored the associations between mortality and various cold indicators of winter in Seoul, South Korea. First, we fitted nonparametric smoothing regression models to check the shape of associations and then fitted threshold models (including two different slopes in a model) to estimate the thresholds and the effects of low temperatures using the Akaike Information Criterion (AIC). The graphical associations between cardiorespiratory, cardiovascular, and all causes of mortality and the cold wave index (CWI = T_{min, previous day} − T_{min, current day}) were observed. We confirmed the threshold according to a lag structure and after that, estimated the effects of CWI below the threshold, respectively. The effects of the daytime CWI lagged by 0-2 days were the strongest among those of the daytime CWI lagged by 0-6 days. The most significant mortality outcomes were cardiovascular-related. Although we could not consider respiratory-related mortality, the effect of CWI on cardiovascular-related mortality below a certain threshold was greater than cardiorespiratory-related or all cause-related mortality. In addition, the association between mortality and CWI was more immediate and vulnerable in an elderly subgroup (≥ 65 years old) than in a younger subgroup (0-64 years old). Our results suggest that public health programs should be considered to alleviate not only the effect of sudden change in winter temperature on mortality.     

温拌剂在西商高速公路试验路段的应用

以陕西西安至商州高速公路36标路面施工为主题,在沥青混合料拌合时添加HH-X温拌剂进行试验,根据试验路段路面压实度检测结果,分析并得出温拌沥青混合料相对于热拌沥青混合料施工的温度降低了约30℃,但沥青温拌混合料路面的使用性能与普通热沥青路面相当,完全满足热拌沥青混合料路面技术要求的结论。     

高温季节混凝土施工如何防止裂缝的产生

根据高温季节混凝土施工的实际情况,从温度应力的形成、裂缝产生的原因等方面作了分析,通过分析给出了防止裂缝产生的一系列措施,以期保证高温季节混凝土施工质量。     

UNF-5对高C_3S水泥初始水化作用效果的温度效应

采用流动度、水化热、电阻率宏观测试以及XRD、原子吸收微观分析,研究了高C3S体系中,UNF-5对水泥初始水化作用效果的温度效应。试验表明:UNF-5在高C3S含量水泥中工作性作用效果存在温度突变点T0,在T0附近,工作性对环境温度的敏感性显著增强;水化加快是减水剂作用下水泥浆体工作性存在温度突变的主要原因;微量的SG组分对高C3S含量水泥体系中UNF-5作用效果的温度敏感性具有显著的削弱效果;采用化学外加剂复配技术是实现高胶凝材料体系高效应用的重要组成部分。     

混凝土高温试验及高温后抗压残余强度研究

介绍混凝土高温试验过程和试验现象。对高温后混凝土的抗压强度进行了力学性能测试,得到高温后混凝土试块的抗压残余强度。综合4种高温后混凝土抗压残余强度公式,通过曲线图形与本试验结果进行对照比较,找出一致性较优公式。