Thermal Comfort Evaluation in Urban Open Space (Case Study: Chamran Street in Kermanshah)

Document Type : Research Paper


1 Department of Architecture, Faculty of Architecture and Urban Planning, JundiShapur University of Technology, Dezful, Iran

2 Mechanical Engineering Department, Faculty of Engineering, Shahid Bahonar University of Kerman, Kerman, Iran


In Iran, there has not been much research and study on the effects of macro-scale climatic factors (especially in the cold climate and cold season); only a few studies on the mental senses of people in urban open spaces have been used in this climate. Is. Therefore, in this paper, we try to investigate the factors affecting cold weather in the cold season in urban streets by examining the thermal comfort index (PMV) and introducing ways to balance the comfort with physical intervention.
This study is carried out for typical winter conditions in Chamran Street in Kermanshah (34.19 N latitude and 47.7 E) located in the Iran. The climate of this city is cold and mountainous. In this article, February 11 was considered as one of the coldest days of the year (one of the most critical days of the year) to study.
The case study has width of 40 meters with a East-West orientation. The height of buildings is between 3 and 39 meters. The ground floor use of this street is mainly commercial and the major materials used in the facade of the buildings, stone and brick, on the floor of the mosaic and concrete Street and in the middle street reflection are also stones.
The shadow projection and the Calendar of Climate Needs for Kermanshah City show that there is a need for radiation in the coldest days of the year (from mid-October to March) . Therefore, providing sunlight is very necessary. In April, you will need both radiation and shadows. In the months of May to September, shade is needed. Therefore, urban spaces should be designed in a way that meets the needs of people in all seasons..
Several tools were used to collect climatic parameters. In this study, we used an anemometer to measure the wind, and to measure the temperature humidity, humidity and spherical temperature from a multi-function data logger. (Table 1). In order to measure physical parameters, the instruments were placed at a height of 1.5 m above the ground plane on a stack in the areas under study. The study area was selected according to the variation in the enclosure of several points to investigate and measure the climate parameters. All points were monitored at 5-minute intervals on February 11. . Multi-function data logger measurements with 30 second intervals were automatically recorded from 9-17. Other measurements were done manually due to lack of data logger. This interval is chosen because the greatest number of people in the urban space occurs at this interval
In this research, the model of the standard Ashrae 55 is used. This climate model is used to calculate and simulate climate variables in urban space with regular grids accuracy of 0.5 to 10 meters.
Observations show that PMV has changed tremendous in comparison to the existent situation, and comfort zone have changed over the course of time, but Tmrt has not changed much. In the intervention, this article did not change much in the mean radiant temperature, but the thermal comfort index has changed considerably. As a result of decreasing a building with two feedback 3-meter and 4 meters in height, the PMV at 9 o'clock from a relatively cold zone to cold zone and has reached to comfortable zone at 10-12 o'clock. Between 13 and 15, the most change is observed, with the PMV zone changing from very cold to cool and relatively cold.
Therefore, based on the studies conducted on the basis of studies carried out, in the temperature at 45° to 56°, the street of Chamran is in the comfort zone. Therefore, the design of the spaces should be such as to obtain the highest amount of solar radiation , in order to improve the comfort of the spaces. Therefore, it is suggested that in the future development plan of the city, it should be proposed in the South Front building, to feedback for buildings above 24 meters Because the best way to improve the comfort of Chamran Street in winter is having a 30-32° shadow angle, which PMV will have the best of situation..
Recent studies have shown that the closure of urban canyons affect on the microclimate at the street level. This study, Thermal Comfort in an Urban Street Cold Region Calculated by using physics parameters and evaluation personal variables . This study also had the goal to Calculated Thermal Comfort in an Urban Street Cold Region by software was able to evaluated outdoor thermal perception, One of the output data of ENVI-met is the Predicted Mean Vote (PMV), a thermal comfort index based on a 7-point scale ranging from -3 to +3. This study has examined techniques in responding sufficiently to the urban geometry characteristics, such as H/W ratio and SVF . So, by analyzing field survey and existent and proposed simulation the following results were obtained:
1- To determine the effect of solar radiation on the amount of thermal comfort, the relationship between SVF and PMV is investigated in different locations that are analyzed. In the study area, sections have more opening (higher SVFs) have more potential for solar access in winter , and this improves the comfort of people
2- Based on the simulation carried out on the model, the desired intervention is affected by many changes in the climate and the thermal comfort of the outdoor space. The mean radiant temperature under the influence of some components is significant changes, including the vegetation added to The site is designed to reduce the radiant temperature, which reduces the comfort of people during cold weather. So, reducing the height of high-rise buildings on the street can have an impact on improving the comfort of the street.