scholarly journals O desconforto térmico estival em Lisboa - uma abordagem bioclimática

Finisterra ◽  
2012 ◽  
Vol 33 (66) ◽  
Author(s):  
Henrique Andrade
Keyword(s):  
Air Temperature ◽  
Mean Radiant Temperature ◽  
Wind Regime ◽  
Physiological Equivalent Temperature ◽  
Northerly Wind ◽  
Thermal Discomfort ◽  
Daily Data ◽  
Human Energy ◽  
Hot Days ◽  
Radiant Temperature

THE SUMMER THERMAL STRESS IN LISBOA; A BIOCLIMATIC APPROACH. The summer frequency of hot days was studied, in Lisboa/Portela, with daily data from the period 1981/97. We used the Physiological Equivalent Temperature, an index of thermal confort based on the human energy balance, and calculated with air temperature, vapour pressure, wind speed and mean radiant temperature. It was assumed that mean radiant temperature was equal to air temperature, which is acceptable in the shade. The days were classifiend in two groups: hot days and very hot days, according to the thresholds of PET of 29ºC and 35ºC; 10% of the days had warm stress, with a maximum of frequency in July and a great interanual variability. The relation between the thermal discomfort and the wind regime was analysed. Most of the unconfortable days had breeze conditions, with the wind blowing from the East (from the estuary) during the morning; in the afternoon, the barometric gradient between the Ocean and the Iberian Peninsula increases, the breeze is replaced by a week northerly wind. The frequent occurence of strong northerly winds in summer is an important factor of reduction of the warm stress in Lisbon

scholarly journals Integrated Weather Effects on Cycling Shares, Frequencies, and Durations in Rotterdam, the Netherlands

2014 ◽  
Vol 6 (4) ◽  
pp. 468-481 ◽  
Author(s):  
Lars Böcker ◽  
Sofia Thorsson
Keyword(s):  
Wind Speed ◽  
The Netherlands ◽  
Air Temperature ◽  
Panel Study ◽  
Thermal Conditions ◽  
Meteorological Variables ◽  
Mean Radiant Temperature ◽  
Physiological Equivalent Temperature ◽  
Transport Modes ◽  
Radiant Temperature

Abstract With the increasing societal interest in climate change, health, accessibility, and liveability and subsequent policy aims to promote active transport modes over car usage, many scholars have investigated the relationship between weather and cycling. Existing studies, however, hardly address the effects of weather on cycling durations and often lack assessments of the combined effects of different meteorological variables and potential nonlinearity of these effects. Drawing on travel diary data from a panel study of 945 Greater Rotterdam respondents (the Netherlands), this paper investigates and compares the effects of different meteorological variables, singly as well as combined, on cycling frequencies, cycling durations, and the exchange between cycling and other transport modes. Results show linear negative effects of precipitation sum and wind speed and nonlinear bell-shaped effects of thermal variables on cycling and opposite effects on car usage. Out of three thermal variables investigated, mean radiant temperature (radiant heat exchange between humans and the environment) and physiological equivalent temperature (an index combining the effects of air temperature, mean radiant temperature, air humidity, and wind speed) better explain cycling behavior than just air temperature. Optimum thermal conditions for cycling were found on days with maximum air temperatures around 24°C, mean radiant temperatures around 52°C, and physiological equivalent temperatures around 30°C. Policy and planning implications are highlighted that could reduce cyclists’ exposures to disadvantageous weather conditions such as heat, precipitation, and wind, at present and in a potentially changing climate.

scholarly journals Optimizing Street Canyon Orientation for Rajarhat Newtown, Kolkata, India

2017 ◽  
Vol 21 (1) ◽  
pp. 5-17 ◽  
Author(s):  
Bhaskar De ◽  
Mahua Mukherjee
Keyword(s):  
Air Temperature ◽  
Orientation Angle ◽  
Anthropogenic Heat ◽  
Outdoor Thermal Comfort ◽  
Wave Radiation ◽  
Humid Climate ◽  
Street Canyons ◽  
Physiological Equivalent Temperature ◽  
Urban Geometry ◽  
Radiant Temperature

Abstract Air temperature in urban street canyons is increased due to the morphed urban geometry, increased surface area, decreased long wave radiation and evapo-transpiration, different thermo-physical properties of surface materials and anthropogenic heat which results in thermal discomfort. Outdoor thermal stress can be mitigated substantially by properly orienting the canyons. It is crucial for the urban planners and designers to orient street canyons optimally considering variable local climatic context. It is important especially for cities in warm humid climatic context as these cities receive higher insolation with higher relative humidity and low level macro wind flow. This paper examines influence of canyon orientation on outdoor thermal comfort and proposes the optimum canyon orientation for the Rajarhat Newtown, Kolkata – a city in warm humid climate zone. Different scenarios are generated with different orientations. Change in air temperature, wind speed, Mean Radiant Temperature (MRT) and Physiological Equivalent Temperature (PET) of different scenarios are compared to find out the optimum orientation by parametric simulation in ENVI_met. Analysing the simulation results it is observed that orientation angle between 30°–60° to north performs the best for the study area of the Rajarhat Newtown. The findings of this research will be helpful for the planners to orient the street canyons optimally for future development and extension of the Rajarhat Newtown, Kolkata.

scholarly journals Thermal comfort of patients in hospital ward areas

1977 ◽  
Vol 78 (1) ◽  
pp. 17-26 ◽  
Author(s):  
R. M. Smith ◽  
A. Rae
Keyword(s):  
Steady State ◽  
Thermal Comfort ◽  
Air Temperature ◽  
Hospital Ward ◽  
Patient Comfort ◽  
Mean Radiant Temperature ◽  
Air Velocity ◽  
Assessment Techniques ◽  
The Mean ◽  
Radiant Temperature

SUMMARYThe patient is identified as being of prime importance for comfort standards in hospital ward areas, other ward users being expected to adjust their dress to suit the conditions necessary for patient comfort. A study to identify the optimum steady state conditions for patient comfort is then described.Although this study raises some doubts as to the applicability of the standard thermal comfort assessment techniques to ward areas, it is felt that its results give a good indication of the steady-state conditions preferred by the patients. These were an air temperature of between 21.5° and 22° C and a relative humidity of between 30% and 70%, where the air velocity was less than 0.1 m/s and the mean radiant temperature was close to air temperature.

scholarly journals Changes in the extreme air temperature in Czech Republic

2021 ◽  
Vol 101 (1) ◽  
pp. 77-87
Author(s):  
Nina Nikolova ◽  
Martin Bárta
Keyword(s):  
Czech Republic ◽  
Air Temperature ◽  
Negative Trend ◽  
Positive Trend ◽  
Climate Conditions ◽  
Cold Part ◽  
Daily Data ◽  
Hot Days ◽  
Cold Events ◽  
Extreme Cold

This study is focused on air temperature in Czech Republic in relation to selected climatological indices for extreme hot and extreme cold days for the period 1961- 2017. The number of summer days (SU) and number of tropical days (SU30) have been chosen as the indicators of extreme hot days. For the indicators of extreme cold days, the number of frost days (FD) and number of icing days (ID) have been analyzed. The analyses are based on the daily data for air temperature measured at eight meteorological stations situated at the regions with different geographical and climate conditions. The data are freely available from the website of the Czech Hydrometeorological Institute. The results of the study show negative trend of extreme cold events and positive trend of extreme hot temperatures. With a few exceptions, the trend is statistically significant at p=0.05. The trend values for the indicators of cold days are higher than those for the indicators of warm days. The results show a faster change in air temperature for the cold part of the year

Effect of Glazed Ratio on Indoor Comfort and Energy Need for Heating

2016 ◽  
Vol 861 ◽  
pp. 183-189
Author(s):  
Attila Kerekes
Keyword(s):  
Heat Loss ◽  
Air Temperature ◽  
Indoor Air ◽  
Thermal Mass ◽  
Mean Radiant Temperature ◽  
Existing Buildings ◽  
Operative Temperature ◽  
Radiant Temperature ◽  
Simplified Calculation ◽  
Indoor Comfort

According to the current national regulations appropriate operative temperature must be provided in premises. Nevertheless simplified calculation methods of heating built-in capacity and energy need for heating are based on indoor air temperature: to have the same output in function of operative temperature requires a series of iteration or dynamic simulation. Experience in existing buildings shows that higher glazed ratio is accompanied by decreasing Mean Radiant Temperature to be counterbalanced with higher indoor air temperature in order to keep the prescribed operative temperature. Nevertheless, in well insulated buildings this effect is weaker. Moreover, it turns into opposite: high Mean Radiant Temperature should be compensated with lower indoor air temperature which considerably decreases the heat loss – especially the ventilation heat loss. Energy need for heating of a sample building is analysed in the function of thermal insulation, glazed ratio and thermal mass.

The Effect of Urban Design on Outdoor Thermal Environment in a Central Business District Area in Singapore

2014 ◽  
Vol 1073-1076 ◽  
pp. 1428-1432
Author(s):  
Wei Yang ◽  
Yao Lin Lin ◽  
Nyuk Hien Wong
Keyword(s):  
Numerical Simulation ◽  
Urban Design ◽  
Air Temperature ◽  
Thermal Environment ◽  
Central Business District ◽  
Width Ratio ◽  
Mean Radiant Temperature ◽  
Outdoor Thermal Environment ◽  
Business District ◽  
Radiant Temperature

Outdoor thermal environment in urban spaces is important for people to enjoy the urban environment. This paper investigated the effect of urban design on outdoor thermal environment in an urban street in the central business district in Singapore, focusing on street orientation and height-to-width ratio. The microclimatic parameters of different street design scenarios were determined by ENVI-met numerical simulation. Field measurement was conducted to validate the results from the numerical simulation and they were in good agreement. For different design scenarios, it is found that (1) The air temperature differences did not exceed 0.8°C; (2) The mean radiant temperature differences could exceed 40°C; (3) The maximum wind speed difference was 0.6 m/s; (4) No distinct relative humidity differences could be found. The results show that shading is the key strategy for improving outdoor thermal environment in Singapore because it leads to reduction on the air temperature and mean radiant temperature simultaneously. N-S orientated street had the best thermal environment condition.Outdoor thermal environment in urban spaces is important for people to enjoy the urban environment. This paper investigated the effect of urban design on outdoor thermal environment in an urban street in the central business district in Singapore, focusing on street orientation and height-to-width ratio. The microclimatic parameters of different street design scenarios were determined by ENVI-met numerical simulation. Field measurement was conducted to validate the results from the numerical simulation and they were in good agreement. For different design scenarios, it is found that (1) The air temperature differences did not exceed 0.8°C; (2) The mean radiant temperature differences could exceed 40°C; (3) The maximum wind speed difference was 0.6 m/s; (4) No distinct relative humidity differences could be found. The results show that shading is the key strategy for improving outdoor thermal environment in Singapore because it leads to reduction on the air temperature and mean radiant temperature simultaneously. N-S orientated street had the best thermal environment condition. Shading achieved by means of high aspect ratios can improve thermal environment at street level.

Differents Methods to Estimate the Mean Radiant Temperature in an Urban Canyon

2013 ◽  
Vol 650 ◽  
pp. 647-651 ◽  
Author(s):  
R. de Lieto Vollaro ◽  
A. Vallati ◽  
S. Bottillo
Keyword(s):  
Human Body ◽  
Street Canyon ◽  
The Other ◽  
Radiation Environment ◽  
Mean Radiant Temperature ◽  
Radiation Fluxes ◽  
Human Energy ◽  
Environment Simulation ◽  
The Mean ◽  
Radiant Temperature

The mean radiant temperature is one of the meteorological key parameters governing human energy balance and the thermal comfort of human body. This variable can be considered as the sum of all direct and reflected radiation fluxes to which the human body is exposed. After the basics of the Tmrt calculation a comparison between two methods suitable for obtaining Tmrt in a street canyon will be presented. One of the discussed methods of obtaining Tmrt is based on the utilization of a globe thermometer. The other method is the radiation environment simulation through three PC software (RayMan, ENVI-met and SOLWEIG).

scholarly journals UTCI applications in practice (methodological questions)

2021 ◽  
Vol 94 (2) ◽  
pp. 153-165
Author(s):  
Krzysztof Błażejczyk ◽  
Magdalena Kuchcik
Keyword(s):  
Wind Speed ◽  
Human Health ◽  
Air Temperature ◽  
Meteorological Data ◽  
Mean Radiant Temperature ◽  
Change Analysis ◽  
Complex Index ◽  
Wide Range ◽  
Radiant Temperature

UTCI, although it was developed with the participation of scientists from 22 countries, it has shortcomings and people using it face various obstacles. The difficulties include wide range of issues: from different availability of meteorological data in individual countries, through the kind of air temperature which should be properly used in calculations, or the need of recalculation of wind speed. However the biggest subject concern algorithms for mean radiant temperature (Mrt) calculations, different models and programs which simplify calculations of this complex index though introduce different approximations and, as a result, many false results. The paper presents also wide range of UTCI applications in urban bioclimate studies and bioclimatic mapping, climate-human health researches and biometeorological forecasts which were the primary purpose of the index creation, but also applications in tourism and recreation or even in bioclimate change analysis.

Sign in / Sign up

Export Citation Format

Share Document