فهرست مطالب حجت قیاسوند

In a cold climate, it is necessary to correctly determine the window geometry parameters in order to access sunlight and improve thermal performance. The window is one of the main factors that can increase the demand for cooling energy in summer and reduce heating energy in winter. Therefore, the goal is to investigate the effect of window geometry parameters (WWR, U, SHGC, Shading) on energy consumption, in order to determine the optimal window level of the cold climate urban housing of Hamedan city. The ratio of the surface of the window to the wall and its geometric parameters, as an independent variable, and the amount of energy consumption, is a dependent variable.

The type of research is quantitative and based on the numerical data of the window-to-wall surface (WWR) and energy simulation, and statistical methods have been used in the analysis of the findings. In the data analysis, Pearson's correlation coefficient analysis, variance comparison analysis and follow-up tests were used to determine the relationship between the variables and determine the optimal level (WWR). This study in four stages; Investigating the window-to-wall surface ratio (WWR) of traditional houses, the effect of the WWR of the north and south facades of contemporary housing on building energy, the optimization of WWR due to variables (U, SHGC, SHADING) and the determination of the optimal level have been carried out.The statistical population of this research is in the first part of the selected houses of traditional housing in Hamadan city and to simulate contemporary housing, of the northern and southern parts in the new texture (conventional linear pattern) with an area of 240 square meters in each plot.

the results showed that; The southern front of traditional housing has 55.69% more glass wall surface than the north-facing front. In the contemporary context of Hamadan city, adding windows to the south-facing walls reduces the heating, lighting and final energy, and the north-facing walls increase the cooling, heating and final energy. The south-facing front has a better thermal performance than the north-facing front with a decrease in final energy (-21.55%). In cold climate, the lower the value of U and SHGC, the lower the energy consumption and the type of relationship is direct. For the north face, shading has no effect on energy consumption. But for the southern front, horizontal and combined fixed shading are effective and reduce cooling energy and increase heating energy, so to prevent the increase of heating energy due to the creation of fixed shading, movable shading can be used, Or it is better to reduce the amount of heating energy consumption by increasing the vertical distance of the awning from the top of the window.

On the south front, the optimal window-to-wall level equal to 60% WWR has a final load reduction of -18.52%, and on the north facing front, WWR = 40% has a final load reduction of -8.38%. Based on the results, a revision proposal has been presented in Appendix 10, Topic 19 of the National Building Regulations.

This study examines the effect of geometrical indices of a street (Orientation and H/W) on the buildings` direct solar access on an urban scale, which its results can be used by urban planners in designing new neighbourhoods and redeveloping old ones in developing cities. In cold climates, the access of buildings to sunlight due to the street geometry index is necessary to reduce the heating load and affects the thermal performance of buildings. This index (height to width ratio (H/W) and orientation) directly affects the absorption and emission of urban sunlight and changes in them can affect the amount of solar radiation absorption of the building.This study aims to investigate the amount of the buildings` solar has gained in the cold climate of Hamedan. The research method is quantitative and based on numerical data of simulating solar radiation and the geometry of the urban texture of Hamedan. Data analysis was conducted by statistical analysis of box diagram, correlation coefficient, and reference model. First, to examine the effect of street width index, fixed height, and variable street width (6 to 36 meters) and then to examine the height index, fixed street width and variable height (3 to 9 floors) were considered in the modelling. The findings reveal that east-west oriented buildings have the highest solar gain of 17.9% in the winter, and nearly 60% of the streets in the new urban texture of Hamedan are placed in the non-optimal orientation.The average solar gain in northern blocks is more than in southern blocks and streets; with a lower H/W index this gain increases indicating a reverse and intensive correlation. Index H/W compared to orientation has the greatest effect on a solar gain on the building located alongside streets.  In shallow geometrical valleys, the temperature from radiation is higher than in deep valleys and as the H/W index rises, i.e., as the street becomes narrower, the direct solar gain decreases. In southern blocks, due to a deep valley in the yard, most of the south façade of a building in the winter is always in the shade of building volumes and absorbs little solar radiation. In this state, the greatest amount of absorption is reflective and scattered. Therefore, increasing the depth of the yard in these blocks to absorb more sunlight was studied in our recommended pattern. From the measured indices in this study, the H/W index has the greatest impact on solar gain for buildings located alongside streets. This index has a 123% higher influence compared to the orientation index on absorbing radiation and is of more importance. In Hamedan, regarding the H/W index, a twelve-meter street has the least absorption, thirty-five-meter, and seventy-five-meter streets have the most absorption in the winter. In our recommended patter, increasing the depth of the yard and using vertical shades for windows leads to a 2.7% and 25.8% rise in solar gain for northern and southern blocks, respectively. This pattern reduces 11.7% and 4.94% of absorption for the mentioned blocks in the summer.

The relationship between building density and energy consumption involves a complex interaction between climate factors, location patterns, the way urban open spaces are located, and the adjacency of the buildings of which they are composed. Therefore, this study investigated the thermal performance of residential buildings based on the patterns of residential blocks in Hamadan Province, Iran using the concept of minor climate and thermal islands influenced by density regulations. It aimed to evaluate the effect of these regulations on energy consumption. A comprehensive collection of thermal simulations were conducted based on the climate of Hamadan and a statistical analysis for examination of the effect of height on the energy consumption resulting from increased urban density.

 Theoretical Framework

A criterion used for measurement of the energy consumption of buildings is the micro-urban climate resulting from the density regulations (H/W).  These regulations can affect the access of buildings to sunlight and, thus, the energy performance of buildings. Density regulation indices include two categories: middle-scale and micro-scale. The middle-scale category involves an H/W criterion for measurement of the impact of the outdoor environment. The micro-scale category involves criteria for changes in the building volume geometry, including the surface-to-volume ratio (S/V), ratio of surface exposed to direct sunlight to total surface (Ssn/Ssh), shadow area (Ssu/Ssh), substructure (Ssu/A), volume (Ssu/V), and ratio of window surface to the total wall surface (WSR), which changes as height varies. 

The methodology involved a combination of qualitative and quantitative methods. In the simulation stage, two modes were considered to specify the effect of H/W on energy consumption. First, fixed height and variable street width were considered in the modeling for examination of the effect of the street width index, and fixed street width and variable height were then considered for examination of the height index. For analysis of the findings of the statistical methods, correlation, analysis of variance, and multiple regression were used.The relationships between energy consumption and the variable of street width and each of the indicators of the variable of height were investigated with the Pearson correlation coefficient. For investigation of the simultaneous effect of all the indices of the independent variable on the dependent variable (energy consumption), multiple regression analysis was used to specify which geometric factor exhibited the greatest impact on energy consumption. Analysis of variance was used for comparison and evaluation of the mean differences between the groups.
For validation, two methods were used: experimental (involving field measurements) and comparative (involving a comparison of the results of different software).

The results obtained from the correlation analysis revealed that there is a close direct relationship in all residential blocks of northern patterns between H(fix)/W(6m-36m) and annual energy consumption, while there is no correlation in southern patterns. The relationship between H(4f-10f)/W(fix) and annual energy is direct in northern patterns but inverse and slightly effective in southern patterns.As the H(fix)/W(6m-36m) ratio decreases, cooling energy consumption increases sharply (inverse correlation), and heating and total energy consumption decrease sharply (direct correlation). In this analysis, energy savings are greater on a wider street than on a narrower street, and fixed-height buildings exhibit lower annual energy consumption on a wider street.Positive correlation (high intensity) and negative correlation with heating energy (low intensity) is established between the geometric characteristics of residential parts (S/V, Ssu/S, Ssu/V, Ssu/Ssh, and Ssn/A) and cooling energy consumption. Wider streets receive more sunlight than narrower ones, so those with lower geometric indices exhibit better thermal performance and greater reduction of heating energy consumption.

Building density and its indices are influential in northern patterns, and increase in height and pathway width contributes to the reduction of energy consumption. Therefore, the geometric index of an urban street is effective in northern patterns, and a rise in height through an increase  in the horizontal distance between buildings affects the reduction of energy consumption. However, the value of the index (H/W) is lower on the urban passages of the cold climate of Hamadan (deep urban valleys), and the energy consumption of the building decreases as the absorption of solar radiation increases. Multiple regression analysis showed that the most indicative energy consumption factors in the patterns included the geometric index (H/W), the number of sunny surfaces (Ssu), the ratio of shadow (Ssh) to the substructure (A), and total surface area (S) . The proposed model (involving a change in the occupancy level of the initial model) exhibited the most optimal thermal performance with decreases by 42.9% in cooling energy and by 4.73% in total energy.

Acknowledgment

The article has been derived from the Ph.D. thesis entitled "Determination of housing deployment pattern considering the influence of climate factors on the inside thermal comfort whit an energy management approach (case study Hamedan)", which has been defended by the first author under the second author’s supervision and the third author’s advisory at the Qazvin Branch, Islamic Azad University.

Increase in urban population and development of cities has led urban planning and designing into a new stage of sustainable development so that the importance of effective energy design to develop cities sustainably, especially in urban housing, seems vital. One of the main principles of sustainable climate development is to examine how residential buildings are suited to enhance their thermal performance in cities. Therefore, this study aims to examine the components and geometrical indices of physical location influencing thermal performance in the design stage in the Cold semi-arid climate of Hamedan. The factors influencing the thermal performance of physical location regarding theoretical foundations and the literature were investigated. The physical location of residential complexes has different influencing factors for saving energy, such as the direction of the buildings, the form of mass-space at the site, and the height (density) with various geometrical characteristics. 

 The research method combines qualitative (descriptive, analytical, and field observation) and quantitative (energy simulation data) methods. Data analysis was conducted using statistical methods, correlation test, ANOVA, T-test, and comparison with the reference model. The independent variable is physical location components (direction, mass-space, and height), and the dependent variable is annual energy consumption. 

 15 residential buildings were coded and simulated by identifying four main groups and their subgroups in Hamedan. The findings revealed that physical location components influence energy consumption intensely. Choosing the proper direction can save a significant amount of energy in most patterns, mostly linear patterns. Correlation analysis among geometrical indices influenced by mass-space and energy consumption indicates a direct and intense relationship. The fewer amounts of indices, including the window–to–gross area, the ratio of area-to-mass, the, and occupation level line are, the more energy is saved. Then they are regarded as the main priority of designing. Increase in height and its influencing geometrical indices leads to a decrease in cooling energy consumption and has different results in the consumption of heating energy and the total energy. 

 The most optimal physical location is west-east oritation, and the least suitable one is north-south to 120 degrees. Dense patterns with fewer occupation level lines are the most suitable mass-space pattern in residential complexes. By comparing the patterns with the reference model, linear patterns with an average of 13.05% energy saving are optimal. Sparse patterns are the most inefficient, with an average of 5.86% saving, and dense and combined patterns have moderate energy saving. Patterns with the most area to the volume of blocks are not considered suitable in a cold climate for residential complexes. Correlation analysis between height (increase in surface-area-to-volume ratio and H/W) and energy consumption shows that among the six patterns being investigated, there is an increase in consumption in 2 patterns, and in the other six patterns, there is a noticeable decrease in energy consumption.