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Vibration performance of cross-laminated timber (CLT) floor under multi-person load
Since the 1970s occupant complaints about vibration serviceability performances of lightweight timber floors have risen in many countries. Initially concerns commonly centered on behaviours of joisted floors in non-commercial buildings. Empirical design methods were developed, but those methods sidestepped generalize understanding of the issues. Subsequent evolution of building construction techniques and material options often exacerbated inadequacies of empirical design methods. Consequently, interest in understanding why vibration serviceability problems occur and how to avoid them has reemerged as a priority research topic. This paper discusses technical issues associated with predicting vibration serviceability performances of lightweight timber floors, and identifies best current analysis and design practices. Emphasis is on ability to handle the full range of variables associated with 21st century lightweight construction methods. This includes capability to address effects of architectural and construction design choices, and effects types of building occupancies have on dynamic loads and motion responses of floor systems. Need to utilize capabilities of modern numerical engineering analysis tools is also emphasized. Ongoing R&D activities are mentioned, including need to address Human-Structure Interaction effects commonly important to proper design of lightweight building superstructures.
Overheating in buildings is a growing challenge in the context of climate change and global warming. Many researchers are focusing on developing different passive strategies to minimize overheating and cooling electrical consumption in buildings. Thermal mass provides thermal energy storage, which could be utilized to store extra heat during hot summers to avoid overheating. To fulfill the cyclical behavior of the thermal mass, it must be discharged to store heat again and follow this charging-discharging process on a daily basis to modulate overheating. Night ventilation performs the discharging phenomenon to maximize the effect of the thermal mass. Shading devices prevent the penetration of solar radiation into the building in summer. The aim of this study was to evaluate the effect of thermal mass and night ventilation to modulate overheating in the cold climates in Beijing, China. A model of the BESTEST ASHRAE Standard 140 Case 600FF was used to perform full-year dynamic building simulations with Energyplus at different levels of thermal mass. The results allow optimizing the thermal mass configuration according to each climatic condition and in accordance with the performance of night ventilation and shading devices availability. The results confirm the important role played of night ventilation and shading devices to modulate overheating with the potential to reduce maximum temperatures up to 20% by using heavyweight thermal mass compared to lightweight. The results of this study will help to develop the decision support systems to inform the implementation of thermal mass into regional and local building regulations.
Night ventilation and external blinds are the most commonly used passive methods to protect buildings from overheating during high summer temperatures. Another recommended measure is high thermal inertia of buildings. The aim of the study was to compare the effectiveness of night ventilation, external blinds and thermal mass on the summer thermal performance of a building in a temperate climate. Increasing the thermal mass of the room from light to very heavy without night ventilation resulted in a reduction of the average peak temperature by 3.7 K in a day and 1.2 K by night. The activation of night ventilation in a light room resulted in a reduction of the average value of the peak temperature by 1.5 K during the day and 5.9 K at night. Increase of thermal mass from light to heavy and night ventilation from 0.6 to 10 ACH led to decrease of average peak temperature by 4.7 K in a day and 4.6 K by night. The simultaneous increase of thermal mass, activation of night ventilation and closing of external blinds resulted in lowering the average peak temperature by 7.4 K in a day and 6.3 K by night. The analysis of the test results indicates that the high thermal mass and the closing of the external blinds reduces the diurnal variations of the indoor temperature, while the activation of night ventilation increases it significantly, especially for lightweight construction.
The main objective of this paper is to demonstrate the effectiveness of increasing the thermal capacity of a residential building by using traditional building materials to reduce the risk of its excessive overheating during intense heat waves in a temperate climate. An additional objective is to show that the use of this single passive measure significantly reduces the risk of overheating in daytime rooms, but also, though to a much lesser extent, in bedrooms. Increasing the thermal mass of the room from light to a medium heavy reduced the average maximum daily temperature by 2.2K during the first heat wave and by 2.6K during the other two heat waves. The use of very heavy construction further reduced the average maximum temperature for the heat waves analyzed by 1.4K, 1.2K and 1.7K, respectively, giving a total possible reduction in maximum daily temperatures in the range of 3.6 °C, 3.8 °C and 4.3 °C. A discussion of the influence of occupant behavior on the use of night ventilation and external blinds was carried out, finding a significant effect on the effectiveness of the use of both methods. The results of the study suggest that in temperate European countries, preserving residential construction methods with heavy envelopes and partitions could significantly reduce the risk of overheating in residential buildings over the next few decades, without the need for night ventilation or external blinds, whose effectiveness is highly dependent on individual occupant behavior.
China's climate has been warming since the 1950s, with surface air temperature increasing at a rate higher than the global average. Changes of the climate have exerted substantial impacts on water resources, agriculture, ecosystems, and human health. Attributing past changes to causes provides a scientific foundation for national and international climate policies. Here, we review recent progress in attributing the observed climate changes over past decades in China. Anthropogenic forcings, dominated by greenhouse gas emissions, are the main drivers for the observed increases in mean and extreme temperatures. Evidence of the effect of anthropogenic forcings on precipitation is emerging. Human influence has increased the probability of extreme heat events, and has likely changed the occurrence probabilities for some heavy precipitation events. The way a specific attribution question is posed and the conditions under which the question is addressed present persistent challenges for appropriately communicating attribution results to non-specialists.
Building shading devices can improve the thermal comfort in indoor environment, and also reduce cooling and heating energy consumption in dry and hot climate. This study proposes the different kind of window’s fixed shading devices for energy consumption under near-extreme summer and winter conditions by conducting residential building energy simulations in Shiraz climate. Which fixed shading devices optimal configurations that give maximum energy consumption can be used in Shiraz climate. The study was based on modeling-simulation experiments where Ecotect models resented the actual building energy with and without shading devices to reducing heating and cooling load and peak consumption. The results obtained confirmed the accuracy of the model and the suitability of (horizontal, eggcrate and geometrical) of shading devices in reducing the solar gains in summer with reduced blocking of solar radiation in winter. In all cases it has been proven that excessive obstruction may yield an excessive reduction in a range of illuminances between 500 and 2000 lux, increasing lighting energy consumption. At the end results showed that horizontal, geometrical and eggcrate have the best function according to reduce energy and have enough day lighting in the zones in shiraz climate.
The planning of future energy policies and energy systems requires an understanding of the intricate relationships between climate change, technology uptake, population growth and building energy demand. Building cooling demand is expected to increase considerably in many parts of the world as the climate warms on average. In temperate climates, this increase is expected to be particularly large due to the increase in the number of days when cooling is required to maintain a comfortable indoor building temperature. We quantify the impact of climate change, cooling device uptake and population growth based on population-weighted climate models, population growth scenarios and measured thermal energy demand data for Switzerland. This study incorporates three climate development scenarios and we find for an extreme case, that up to 17.5 TWh cooling energy would be required by the middle of the 21st century compared to 3–5 TWh in more moderate cases. Heating energy demand is expected to decrease to around 20 TWh by mid-century, which is approximately one-third of the current Swiss building heating demand. The presented combined quantification of future cooling demands for Switzerland provides a set of benchmarked energy demands and highlights the critical role of air-conditioning technology uptake, which significantly contributes to future cooling demands. Pursuing alternative cooling strategies is therefore needed to limit cooling energy demand impacts on the future energy systems particularly in countries with temperate climates.
Suicide prevention has become a public health issue of great concern. Previous studies proved that ambient temperature had an impact on suicide death, but few studies focus on regional studies in large cities. We aimed to estimate the association between ambient temperature and suicide in 31 capital cities in China during 2008~2013. Distributed lag non-linear model was used to explore the relationship between ambient temperature and suicide, adjusting for long-term trend, seasonality, and humidity confounders. Multivariate meta-analysis was used to pool the city-specific estimates to explore the overall relative risk in China. High temperature had a significant impact on suicide death. The country-level relative risk of high temperature on suicide was 1.37 (95% CI, 0.96~2.57), and the RR was higher in male and age < 65-year-old group than that in female and age ≥ 65-year-old group. There has no consistent pattern of associations in city-level with sex and age. The high temperature has a greater impact on suicide in south region compared with north region. We found the positive association between ambient temperature and suicide in China.
High-temperature weather appears in high frequency, big strength, and long duration in the summer. It is therefore important to study the effects of high-temperature weather on sleep quality and appetite. Ten healthy college students were selected as subjects. The experiment conditions were divided by the daily maximum temperature into 28 °C, 32 °C, 36 °C, and 38 °C. The objective sleep quality was measured by an intelligent sleep monitoring belt, and the subjective sleep quality was measured by a questionnaire survey. The subjective appetites were assessed by a visual analog scale (VAS), and the objective appetites were assessed by the meal weight and the meal time. For sleep quality, the objective results indicated that the sleep quality at 32 °C was the best, followed by 28 °C, while the sleep quality at 36 °C and 38 °C was the worst. Significant effects were mainly reflected in sleep duration and shallow sleep. The subjective results showed that temperature had significant effects on sleep calmness, difficulty in falling asleep, sleep satisfaction, and sleep adequateness. For appetite, the VAS results indicated that high temperatures mainly led to a reduction of appetite at lunch time. The meal weights of lunch were larger than those of supper except for 28 °C, and the meal time of lunch and supper was longer than that of breakfast. The meal time of lunch was longer than that of supper except for 36 °C. This paper can provide a study method and reference data for the sleep quality and appetite of human in high-temperature weather.
Three trends will combine to hasten it, warn Yangyang Xu, Veerabhadran Ramanathan and David G. Victor. Three trends will combine to hasten it, warn Yangyang Xu, Veerabhadran Ramanathan and David G. Victor.
The following four key messages derive from the Lancet
Countdown’s 2018 report:
1 Present day changes in heat waves, labour capacity,
vector-borne disease, and food security provide early
warning of the compounded and overwhelming impact
on public health that are expected if temperatures
continue to rise. Trends in climate change impacts,
exposures, and vulnerabilities show an unacceptably
high level of risk for the current and future health of
populations across the world.
2 A lack of progress in reducing emissions and building
adaptive capacity threatens both human lives and the
viability of the national health systems they depend
on, with the potential to disrupt core public health
infrastructure and overwhelm health services.
3 Despite these delays, a number of sectors have seen
the beginning of a low-carbon transition, and it is
clear that the nature and scale of the response to
climate change will be the determining factor in
shaping the health of nations for centuries to come.
4 Ensuring a widespread understanding of climate
change as a central public health issue will be crucial
in delivering an accelerated response, with the health
profession beginning to rise to this challenge.
Climate models provide the principal means of projecting global warming over the remainder of the twenty-first century but modelled estimates of warming vary by a factor of approximately two even under the same radiative forcing scenarios. Across-model relationships between currently observable attributes of the climate system and the simulated magnitude of future warming have the potential to inform projections. Here we show that robust across-model relationships exist between the global spatial patterns of several fundamental attributes of Earth’s top-of-atmosphere energy budget and the magnitude of projected global warming. When we constrain the model projections with observations, we obtain greater means and narrower ranges of future global warming across the major radiative forcing scenarios, in general. In particular, we find that the observationally informed warming projection for the end of the twenty-first century for the steepest radiative forcing scenario is about 15 per cent warmer (+0.5 degrees Celsius) with a reduction of about a third in the two-standard-deviation spread (−1.2 degrees Celsius) relative to the raw model projections reported by the Intergovernmental Panel on Climate Change. Our results suggest that achieving any given global temperature stabilization target will require steeper greenhouse gas emissions reductions than previously calculated.
Objective:
Considering the scarcity of reports from intertropical latitudes and the Southern Hemisphere, we aimed to examine the association between meteorological factors and suicide in São Paulo.
Method:
Weekly suicide records stratified by sex were gathered. Weekly averages for minimum, mean, and maximum temperature (°C), insolation (hours), irradiation (MJ/m²), relative humidity (%), atmospheric pressure (mmHg), and rainfall (mm) were computed. The time structures of explanatory variables were modeled by polynomial distributed lag applied to the generalized additive model. The model controlled for long-term trends and selected meteorological factors.
Results:
The total number of suicides was 6,600 (5,073 for men), an average of 6.7 suicides per week (8.7 for men and 2.0 for women). For overall suicides and among men, effects were predominantly acute and statistically significant only at lag 0. Weekly average minimum temperature had the greatest effect on suicide; there was a 2.28% increase (95%CI 0.90-3.69) in total suicides and a 2.37% increase (95%CI 0.82-3.96) among male suicides with each 1 °C increase.
Conclusion:
This study suggests that an increase in weekly average minimum temperature has a short-term effect on suicide in São Paulo.
Based on the high-resolution gridding data (CN05) from 2416 station observations, a grid dataset of temperature and precipitation extreme indices with the resolution of 0.5° × 0.5° for China region was developed using the approach recommended by the Expert Team on Climate Change Detection and Indices. This article comprehensively presents temporal and spatial changes of these indices for the time period 1961–2010. Results showed widespread significant changes in temperature extremes consistent with warming, for instance, decreases in cold extremes and increases in warm extremes over China. The warming in the coldest day and night is larger than the warmest day and night, respectively, which is concurrent with the coldest night larger than the coldest day and the warmest night larger than the warmest day. Changes in the number of the cold and warm nights are more remarkable than the cold and warm days. Changes in precipitation extremes are, in general, spatially more complex and exhibit a less widespread spatial coverage than the temperature indices, for instance, the patterns of annual total precipitation amount, average daily precipitation rate, and the proportion of heavy precipitation in total annual precipitation are similar with negative trends in a southwest–northeast belt from Southwest China to Northeast China while positive trends in eastern China and northwestern China. The consistency of changes in climate extremes from the CN05 with other datasets based on the stations and reanalyses is also analysed.
A limited literature base suggests that ambient temperature contributes to suicide, with studies typically focused on a single nation using temporal and spatial aggregated data. We evaluated an association between ambient temperature and suicide in multiple cities in three East Asian countries.
A time-stratified case-crossover method was used to explore the relationship between temperature and suicide, adjusting for potential time-varying confounders and time-invariant individual characteristics. Gender- and age-specific associations of temperature with suicide were estimated, as were interactions between temperature and these variables. A random-effects meta-analysis was used to estimate country-specific pooled associations of temperature with suicide.
An increase in temperature corresponding to half of the city-specific standard deviation was positively associated with suicide in most cities, although average suicide rates varied substantially. Pooled country-level effect estimates were 7.8% (95% CI: 5.0, 10.8%) for a 2.3ºC increase in ambient temperature in Taiwan, 6.8% (95% CI: 5.4, 8.2%) for a 4.7ºC increase in Korea, and 4.5% (95% CI: 3.3, 5.7%) for a 4.2ºC increase in Japan. The association between temperature and suicide was significant even after adjusting for sunshine duration; the association between sunshine and suicide was not significant. The associations were greater among men than women in 12 of the 15 cities although not significant. There was little evidence of a consistent pattern of associations with age. In general, associations were strongest with temperature on the same day or the previous day, with little evidence of associations with temperature over longer lags (up to 5 days).
We estimated consistent positive associations between suicide and higher ambient temperature in three East Asian countries, regardless of country, gender, and age.
Daily numbers of deaths at a regional level were collected in 16 European countries. Summer mortality was analyzed for the reference period 1998-2002 and for 2003. More than 70,000 additional deaths occurred in Europe during the summer 2003. Major distortions occurred in the age distribution of the deaths, but no harvesting effect was observed in the months following August 2003. Global warming constitutes a new health threat in an aged Europe that may be difficult to detect at the country level, depending on its size. Centralizing the count of daily deaths on an operational geographical scale constitutes a priority for Public Health in Europe.
Evidence indicates that improvement of thermal performance of building envelope has the potential for aggravating the indoor overheating risk in summer. On the other hand, evolving building standards continue to strengthen the requirements for thermal performance to achieve the energy-saving target. Therefore, this study quantifies the interaction effect between building standards-oriented building design, heating energy demand in winter, and indoor overheating risk in summer. Building databases with different energy efficiency levels are generated using a randomly generated method. Uncertain variables include not only 13 design parameters but also the running state of natural ventilation and external shading. The indoor overheating risk is assessed in terms of severity and duration. Finally, a multi-objective optimization model integrating metamodels and the non-dominated sorting genetic algorithm is proposed to balance heating energy demand in winter and indoor overheating risk in summer. Results indicate that building standards tend to aggravate overheating risk in summer: the duration and severity of high-performance buildings increased by 40.6% and 24.2% than that of conventional-performance buildings. However, window ventilation could offset the adverse effect, and mitigation of duration and severity can be up to 85.2% and 62.1% for high-performance buildings. Window ventilation can weaken the conflict between heating energy demand in winter and overheating risk in summer. As heating energy demand increased from 6.1 to 67.3 kWh/m2, the overheating risk changes little that the duration of overheating risk decreased from 17.5% to 15.6% and severity decreased from 8.7 °C to 8.3 °C.
Overheating in built environments during climate extreme heat events is a major concern to human health, particularly for people vulnerable to prolonged exposure to heat and humidity. However, currently available methods for assessing the risk of overheating lack robust procedures to evaluate the effects of overheating on the comfort and health of vulnerable occupants residing in the various different dwellings. This paper developed a general methodology to define and characterise overheating events and evaluate the risk to reduced comfort and undesirable health effects of building occupants exposed to extreme heat events. Criteria to declare overheating were developed based on heat-related health outcomes related to limits for body dehydration and core temperature of healthy average-age and older adults. The methodology was then applied to a case study of a residential building with typical local construction practice for cold climates and compared with existing methods for assessing risk from exposure to extreme heat events. The results showed that all the methods predicted that highly insulated and airtight buildings are more prone to overheating than older buildings that are less well insulated and airtight. However, only the proposed methodology described in this paper predicted that natural ventilation through opening windows significantly reduced the overheating risk to below the threshold value. Furthermore, multi criteria methods might be difficult to apply in practice in that it is not guaranteed to violate all the criteria to declare a building space is not overheated. The proposed methodology sets the groundwork for establishing a benchmark model from which different overheating metrics can be compared.
The global trend is to increase the thermal comfort in all kinds of buildings, residential and non-residential. At the same time, minimization of energy consumption and improved building sustainability must be achieved. Only precise calculations can keep the balance between maximizing comfort and minimizing energy consumption. The PassivHaus (PH) is a special type of building with low heating energy consumption that fulfills special requirements defined by the Passivhaus Institut of Darmstadt, Germany. The PassivHaus concept has been successfully implemented in climates other than that of Germany. However, current practice in Southern European countries shows that PHs may exhibit overheating in the hot season, a phenomenon which is not very often encountered in Germany. Shading devices may be considered in these southern countries to improve the thermal comfort in PHs during summer. A model of the AMVIC PH office building located near Bucharest, Romania, has been developed using Simergy and EnergyPlus software. The model was validated and calibrated using measured data during summer. Measurements have been used to estimate the classical thermal comfort indices such as predicted mean vote and predicted percent of dissatisfied. Simulations have been performed to study the effect on thermal comfort of several shading devices, such as exterior blinds, exterior shades, and overhangs. Exterior blinds and exterior shades are generally more efficient than overhangs when the results are discussed with reference to transmitted solar energy flux through the windows.
Objective:
The effects of high temperature on existing allergic conditions are unclear. This study explored the prevalence of allergic symptoms and the effects of high temperature on existing allergic symptoms among an adult population. The effects of high temperature on other non-allergic health outcomes were compared between adults with and without a history of allergic symptoms.
Method:
A cross-sectional telephone survey study was conducted in Hong Kong two weeks after a heat wave in 2017. Socio-demographic information, history of allergic symptoms, non-allergic health symptoms and self-reported changes of allergic symptoms during the study hot period were collected using multiple-choice questions.
Results:
Of the 436 respondents, 24% had reported an allergic history. During the study hot period, 22.4% and 15.7% of those who had skin and nasal allergies had reported worsen symptoms comparing to normal days. Comparing to people without an allergic history, those ever having allergic symptoms reported a higher rate of mucus secretions, mouth ulcers, poorer sleeping quality and worsen mood during the study hot period. The main limitation of this study is the lack of baseline information and the changes in symptoms were based on self-report basis.
Conclusion:
A noticeable proportion of the study adult population reported an allergic history. Some of these symptoms got worse during period of high temperature. Pre-existing allergic symptoms were found associated with more adverse health effects and worse quality of life during hot days. Strategic health promotion policy should be planned to increase the awareness of the potential impacts of high temperature on allergy and the related health issues.
Urban heat island (UHI) could have significant impacts on building energy consumption by increasing space cooling demand and decreasing space heating demand. However, the impacts of UHI on building energy consumption were understudied due to challenges associated with quantifying UHI-induced temperature change and evaluating building energy consumption. We reviewed existing literature for improving the understanding of UHI impacts on building energy consumption. It was found that UHI could result in a median increase of 19.0% in cooling energy consumption and a median decrease of 18.7% in heating energy consumption. The reported UHI impacts showed strong intercity variations with an increase of cooling energy consumption from 10% to 120% and a decrease of heating energy consumption from 3% to 45%. The UHI impacts also showed clear intra-city variation with stronger impact in urban center than that in urban periphery. There were significant differences in the method and the data used to evaluate the UHI impacts in previous studies. Four future research focuses were recommended to better understand the UHI impacts on building energy consumption.
Electricity sector is sensitive to climate change. In this study, a fixed-effect regression feedback model is used to estimate the impacts of climatic factors on electricity demand in China by using panel data of 30 provinces from 1995 to 2016. We also forecast the potential impacts of climate change on future electricity demand under three climate change scenarios. The results show that (1) there is a positive effect of the heating degree day (HDD) and cooling degree day (CDD) on the per capita electricity demand. A 1% increase in the CDD will result in a 0.094% increase in per capita electricity demand, while the same rise of HDD will increase per capita electricity demand by 0.061%. In addition, the per capita electricity demand will decrease by 0.017% if the sunshine duration increases 1%, while the effect of rainfall is not significant. (2) The total changes in electricity demand caused by climatic factors by 2100 under the RCP2.6, RCP4.5, and RCP8.5 scenarios will be 69.52 billion kWh, 222.74 billion kWh, and 518.58 billion kWh, representing 1.0%, 3.53%, and 8.53% of the total electricity consumption in China in 2017, respectively. The effect of climate warming on China's electricity demand is apparent.
Morocco's building sector accounts for about 25% of the country's total energy consumption, including 18% for residential and 7% for the services sector. This energy consumption is expected to raise due to the significant rise of household equipment rate in HVAC facilities mainly air-conditioners. This work presents a methodology combining single-objective optimization and building energy simulation, applied to the study of the effect of optimized overhangs, aimed at improving thermal comfort of a typical two-storey Moroccan existing building in three different climates of Marrakech, Casablanca and Oujda. The optimization has been performed using the non-dominated sorting genetic algorithm (NSGA-II). Optimal and benchmark cases are compared regarding the percentage of annual discomfort, cooling demand and heating demand. The results show that the thermal comfort is improved, and the optimized overhangs reduce the cooling demand by 4.1% for Casablanca's mediterranean climate, which exhibits no contradiction between improvements in thermal comfort and performance.
Residential building heating plays a critical role in building energy conservation in China as it consumes a large proportion of the total primary energy use. Heating energy consumption in China is much larger than that in leading countries. This study investigated the energy saving potential from the building envelope design and actual operation optimization. Results showed that the heating energy consumption target specified in latest forth-step energy efficiency standard in Tianjin still leads to 30.9% higher energy consumption than German building energy efficiency standard EnEv'2009 and 49.7% higher than Passivhaus standard used in Germany. Via field measurement and questionnaire survey during operation, major findings are: (1) high indoor air temperature and window opening for ventilation are accountable for the high heating energy consumption during the operation; (2) radiator heating consumes less energy than radiant floor heating system; (3) temperature-type thermostatic valve and compartment automatic control mode have the best control performance; (4) ventilation device with purifying air unit helps to improve the indoor air quality in the terrible haze weather and to reduce the window opening demand of occupants; (5) heat metering and occupants' energy saving awareness should be encouraged.
Overheating in buildings has been identified as an essential cause of several problems ranging from thermal discomfort and productivity reduction to illness and death. Overheating in buildings is expected to increase as global warming continues. The risk of overheating in existing and new buildings can be reduced if policy makers take decisions about adaptation interventions quickly. This paper introduces a methodology for supporting such decisions on a national level. The methodology aims at (i) quantifying the impact of climate change on the overheating risk, (ii) ranking and characterizing the various building types in terms of their overheating risk and sensitivity to climate change, and (iii) assessing the potential of ventilative cooling to mitigate the effects of climate change. In the case study the overheating risk is evaluated in thousands of dwelling cases (i.e., 9216 possible combinations of several design and operation strategies) consistent with the characteristics of the Dutch dwelling stock built between 1964 and 2013. The overheating risk is assessed for four climate scenarios, which represent historical and future scenarios developed by the Royal Netherlands Meteorological Institute. Computational analyses are carried out using the detailed building performance simulation program IDA-ICE, assisted by a postprocessing calculation model developed in MATLAB®.
Although existing studies have linked high temperature to mortality in a small number of regions, less evidence is available on the variation in the associations between high temperature exposure and cause-specific mortality of multiple regions in China. Our study focused on the use of time series analysis to quantify the association between high temperature and different cause-specific mortalities for susceptible populations for 43 counties in China. Two-stage analyses adopting a distributed lag non-linear model (DLNM) and a meta-analysis allowed us to obtain county-specific estimates and national-scale pooled estimates of the nonlinear temperature-mortality relationship. We also considered different populations stratified by age and sex, causes of death, absolute and relative temperature patterns, and potential confounding from air pollutants. All of the observed cause-specific mortalities are significantly associated with higher temperature. The estimated effects of high temperature on mortality varied by spatial distribution and temperature patterns. Compared with the 90th percentile temperature, the overall relative risk (RR) at the 99th percentile temperature for non-accidental mortality is 1.105 (95%CI: 1.089, 1.122), for circulatory disease is 1.107 (95%CI: 1.081, 1.133), for respiratory disease is 1.095 (95%CI: 1.050, 1.142), for coronary heart disease is 1.073 (95%CI: 1.047, 1.099), for acute myocardial infarction is 1.072 (95%CI: 1.042, 1.104), and for stroke is 1.095 (95%CI: 1.052, 1.138). Based on our findings, we believe that heat-related health effect in China is a significant issue that requires more attention and allocation of existing resources.
Background:
Understanding the health consequences of continuously rising temperatures-as is projected for China-is important in terms of developing heat-health adaptation and intervention programs. This study aimed to examine the association between mortality and daily maximum (Tmax), mean (Tmean), and minimum (Tmin) temperatures in warmer months; to explore threshold temperatures; and to identify optimal heat indicators and vulnerable populations.
Methods:
Daily data on temperature and mortality were obtained for the period 2007-2013. Heat thresholds for condition-specific mortality were estimated using an observed/expected analysis. We used a generalised additive model with a quasi-Poisson distribution to examine the association between mortality and Tmax/Tmin/Tmean values higher than the threshold values, after adjustment for covariates.
Results:
Tmax/Tmean/Tmin thresholds were 32/28/24°C for non-accidental deaths; 32/28/24°C for cardiovascular deaths; 35/31/26°C for respiratory deaths; and 34/31/28°C for diabetes-related deaths. For each 1°C increase in Tmax/Tmean/Tmin above the threshold, the mortality risk of non-accidental-, cardiovascular-, respiratory, and diabetes-related death increased by 2.8/5.3/4.8%, 4.1/7.2/6.6%, 6.6/25.3/14.7%, and 13.3/30.5/47.6%, respectively. Thresholds for mortality differed according to health condition when stratified by sex, age, and education level. For non-accidental deaths, effects were significant in individuals aged ≥65 years (relative risk=1.038, 95% confidence interval: 1.026-1.050), but not for those ≤64 years. For most outcomes, women and people ≥65 years were more vulnerable.
Conclusion:
High temperature significantly increases the risk of mortality in the population of Jinan, China. Climate change with rising temperatures may bring about the situation worse. Public health programs should be improved and implemented to prevent and reduce health risks during hot days, especially for the identified vulnerable groups.
In light of current climate change projections in recent years, there has been an increasing interest in the assessment of indoor overheating in domestic environments in previously heating-dominated climates. This paper presents a monitoring study of overheating in 122 London dwellings during the summers of 2009 and 2010. Dry Bulb Temperature and Relative Humidity in the main living and sleeping area were monitored at 10 minute intervals. The ASHRAE Standard 55 adaptive thermal comfort method was applied, which uses outdoor temperature to derive the optimum indoor comfort temperature. It was found that 29% of all living rooms and 31% of all bedrooms monitored during 2009 had more than 1% of summertime occupied hours outside the comfort zone recommended by the standard to achieve 90% acceptability. In 2010, 37% of monitored living rooms and 49% of monitored bedrooms had more than 1% of summertime occupied hours outside this comfort zone. The findings of this study indicate that London dwellings face a significant risk of overheating under the current climate. Occupant exposure to excess indoor temperatures is likely to be exacerbated in the future if climate change adaptation strategies are not incorporated in Building Regulations, building design and retrofit.
Many countries around the world are confronted with the challenge of decreasing energy consumption, while the use of electrical appliances is continuously increasing in buildings. The requirement to minimize the energy consumption can be fulfilled by revaluating architectural aspects. One of these aspects is related to overheating problems, caused by facades with large, glazed portions. In such designs, shading elements must carefully be integrated and considered at an early-design stage in the design process. Shading of buildings is crucial especially in climates with hot summer. It is significant to protect the window from solar radiation in summer while allowing maximum solar radiation in winter. For this reason, precise figures of their performance are needed. As such, simulation tools are often used for identifying the most suitable shading element that suits the building. In literature, there are many studies that have been done to designate the energy performance of shading devices in buildings by using simulation tools. This study focuses both on the shading device types used in the building sector and the previous studies done for designating the performance aspects of different shading devices types. Numerous studies for different building types located in different climatic regions have been reviewed in order to underline the importance of simulation modeling for shading devices in buildings.
The most direct way in which climate change is expected to affect public health relates to changes in mortality rates associated with exposure to ambient temperature. Many countries worldwide experience annual heat-related and cold-related deaths associated with current weather patterns. Future changes in climate may alter such risks. Estimates of the likely future health impacts of such changes are needed to inform public health policy on climate change in the UK and elsewhere.
Time-series regression analysis was used to characterise current temperature-mortality relationships by region and age group. These were then applied to the local climate and population projections to estimate temperature-related deaths for the UK by the 2020s, 2050s and 2080s. Greater variability in future temperatures as well as changes in mean levels was modelled.
A significantly raised risk of heat-related and cold-related mortality was observed in all regions. The elderly were most at risk. In the absence of any adaptation of the population, heat-related deaths would be expected to rise by around 257% by the 2050s from a current annual baseline of around 2000 deaths, and cold-related mortality would decline by 2% from a baseline of around 41 000 deaths. The cold burden remained higher than the heat burden in all periods. The increased number of future temperature-related deaths was partly driven by projected population growth and ageing.
Health protection from hot weather will become increasingly necessary, and measures to reduce cold impacts will also remain important in the UK. The demographic changes expected this century mean that the health protection of the elderly will be vital.
As floor vibration problems increase, there is a need for simple and reliable methods of determining a floor's dynamic properties. This paper presents a technique called the instrumented heel drop test, in which the floor is excited by a series of heel drops performed on top of a slim load cell placed on the floor. The test is shown to give excellent resolution of natural frequencies in the range 2 - 15 Hz, which corresponds well with the frequency range of interest in floor vibration problems. The method appears to offer some advantages over the well-established technique of instrumented hammer testing, in terms of the quality of frequency resolution and the speed of the test.
Climate change will affect the energy system in a number of ways, one of which is through changes in demands for heating and cooling in buildings. Understanding the potential effect of climate change on heating and cooling demands requires taking into account not only the manner in which the building sector might evolve over time, but also important uncertainty about the nature of climate change itself. In this study, we explore the uncertainty in climate change impacts on heating and cooling requirement by constructing estimates of heating and cooling degree days (HDD/CDDs) for both reference (no-policy) and 550 ppmv CO2 concentration pathways built from three different Global Climate Models (GCMs) output and three scenarios of gridded population distribution. The implications that changing climate and population distribution might have for building energy consumption in the U.S. and China are then explored by using the results of HDD/CDDs as inputs to a detailed, building energy model, nested in the long-term global integrated assessment framework, Global Change Assessment Model (GCAM). The results across the modeled changes in climate and population distributions indicate that unabated climate change would cause building sector’s final energy consumption to decrease modestly (6 % decrease or less depending on climate models) in both the U.S. and China by the end of the century as decreased heating consumption more than offsets increased cooling using primarily electricity. However, global climate change virtually has negligible effect on total CO2 emissions in the buildings sector in both countries. The results also indicate more substantial implications for the fuel mix with increases in electricity and decreases in other fuels, which may be consistent with climate mitigation goals. The variation in results across all scenarios due to variation of population distribution is smaller than variation due to the use of different climate models.
Impacts of 1.5 • C global warming on natural and human systems
- O Hoegh-Guldberg
- D Jacob
- M Bindi
- S Brown
- I Camilloni
- A Diedhiou
- R Djalante
- K Ebi
- F Engelbrecht
- J Guiot
Hoegh-Guldberg, O.; Jacob, D.; Bindi, M.; Brown, S.; Camilloni, I.; Diedhiou, A.; Djalante, R.; Ebi, K.; Engelbrecht, F.; Guiot, J.
Impacts of 1.5 • C global warming on natural and human systems. In Global Warming of 1.5 C: An IPCC Special Report; IPCC:
Geneva, Switzerland, 2018.
Climate Change and Land: An IPCC Special Report on Climate Change, Desertification, Land Degradation, Sustainable Land Management, Food Security, and Greenhouse Gas Fluxes in Terrestrial Ecosystems
Intergovernmental Panel on Climate Change. Climate Change and Land: An IPCC Special Report on Climate Change, Desertification,
Land Degradation, Sustainable Land Management, Food Security, and Greenhouse Gas Fluxes in Terrestrial Ecosystems; IPCC: Geneva,
Switzerland, 2019.
Projection of temperature and precipitation changes over China under global warming of 1.5 and 2 • C
- M Zhou
- G Zhou
- X Lu
- L Zhou
- Y Ji
Zhou, M.; Zhou, G.; Lu, X.; Zhou, L.; Ji, Y. Projection of temperature and precipitation changes over China under global warming
of 1.5 and 2 • C. Acta Meteorol. Sin. 2019, 77, 728-744.
ISO 7730; Ergonomics of the Thermal Environment-Analytical Determination and Interpretation of Thermal Comfort Using Calculation of the PMV and PPD Indices and Local Thermal Comfort Criteria
International Organization for Standardization. ISO 7730; Ergonomics of the Thermal Environment-Analytical Determination
and Interpretation of Thermal Comfort Using Calculation of the PMV and PPD Indices and Local Thermal Comfort Criteria.
International Organization for Standardization (ISO): Geneva, Switzerland, 2005.
The Philosophy behind EN 15251: Indoor Environmental Input Parameters for Design and Assessment of Energy Performance of Buildings Addressing Indoor Air Quality, Lighting and Acoustics
- B W Olesen
Olesen, B.W. The Philosophy behind EN 15251: Indoor Environmental Input Parameters for Design and Assessment of Energy Performance
of Buildings Addressing Indoor Air Quality, Lighting and Acoustics; Comite Europeen de Normalisation: Brussels, Belgium, 2007.
Design Standard for Energy Efficiency of Residential Buildings in Severe Cold and Cold Zones. Ministry of Housing and Urban-Rural Development of the People's Republic of China
JGJ 26-2018; Design Standard for Energy Efficiency of Residential Buildings in Severe Cold and Cold Zones. Ministry of Housing
and Urban-Rural Development of the People's Republic of China: Beijing, China, 2018.
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External shading devices for energy efficient building
- M Shahdan
- S Ahmad
- M Hussin
Shahdan, M.; Ahmad, S.; Hussin, M. External shading devices for energy efficient building. In Proceedings of the IOP Conference
Series: Earth and Environmental Science, Shah Alam, Selangor, Malaysia, 8-9 November 2017; p. 012034.