Impacts of some building passive design parameters on heating demand for a cold region

In this study, the impact of passive design parameters such as building shape and orientation position on heating demand has been theoretically investigated. Therefore, a transient heat transfer problem in the building envelope with insulation and without insulation is solved by using the finite difference method. The considered buildings are placed on the ground with the azimuth angles from 0^°$0^{°}$ to 90^°${90}^{°}$. The heat loss per unit area of the buildings is computed by hour–hour and the yearly energy consumption of the buildings is also determined in the simulation model. The climatic data of Elazigˇ (38.4^°N)$(38.4^{°}\mathrm{N})$, a city located in a cold region of Turkey, are considered for the analysis. It is shown that buildings with a square shape have more advantages, and the most suitable orientation angles are 0^°$0^{°}$ and 80^°${80}^{°}$ for buildings having shape factors (the ratio of building length to building depth ) 2/1 and 1/2, respectively.     

Exergoeconomic analysis and optimization of a solar-assisted heating system for residential buildings

In this study, an exergoeconomic model was developed for analysis and optimization of solar heating systems with residential buildings. The optimum collector area (_Ac$A_{\mathrm{c}}$) and storage volume (V$V$) for solar-assisted heating system in the Elaz??, Turkey (38.7^°N)$(38.7^{°}\mathrm{N})$, weather conditions were obtained using MATLAB optimization toolbox. The energy and exergy losses in each of the components of a solar heating system with seasonal storage were also determined. The results showed that the exergy loss and total cost increased with increasing per house collector area for the trapeze and cylindirical tanks. It was found that the total cost of the cylindrical tank system was higher than that of the other trapeze tank system. The exergy loss at the cylindrical tank was 19.8%, while the exergy loss at the trapeze tank was 8.3%.     

Modeling of a novel Trombe wall with PV cells

A novel Trombe wall with PV cells is presented in this paper. A two-dimensional model of PV glass panel and a model of the PV-Trombe wall system are established. The temperature distribution and electrical performance of the PV-Trombe wall system are also obtained. Results show that according to the measured weather data and the special simulation condition, the temperature difference between the elements with and without PV cell on the glass panel reaches a maximum value of 10.6 ^°${}^{°}$C; the temperature difference between the room with and without PV-Trombe wall reaches a maximum value of 12.3 ^°${}^{°}$C during 3 days; after 7 days’ operation, the all-day temperature of the room with PV-Trombe wall retains at about 13.4 ^°${}^{°}$C and an increase of 5.00% for the electrical efficiency can be achieved.     

A field study on determination of preferences for windows in office environments

We aimed to determine the preferences for windows in office spaces and discover the underlying reasons which may affect design decisions. We conducted a field study on office buildings in Izmir–Turkiye. The research findings indicated that majority of users (48.6%; n=107$n=107$) have preferred firstly window-wall, which has the largest window area, secondly horizontal window (35%; n=77$n=77$) and thirdly square window types (10.9%; n=24$n=24$) for their own workspaces. Although having equal surface areas in the preference scale, square-shaped windows have been preferred much more than the rectangular and round shaped ones and horizontal shaped windows than the vertical ones. The window type, gender, quality of office job and quality of view created significant differences in determining prior factors behind window preferences.     

Thermal performance of non air-conditioned buildings with vaulted roofs in comparison with flat roofs

Vaulted or domed roofs have been frequently adopted by builders and architects throughout the Middle East and other hot dry areas. However, the thermal performance of such buildings under hot dry climatic conditions has rarely been quantitatively studied. In this paper, a detailed finite element model for the investigation of the thermal performance of non air-conditioned buildings with vaulted roofs (VR) is suggested based on two-dimensional unsteady heat transfer in such roofs and solar geometry. This model allows a comparison of the thermal performance of non air-conditioned buildings with a VR and a flat roof (FR) under different climatic conditions. Results obtained by numerical calculation show that, irrespective of building type the VRs are applied to, buildings with a VR have lower indoor temperatures as compared to those with a FR. The reason is that such roofs dissipate more heat than a FR does by convection and thermal radiation at night due to the enlarged curved surfaces. This implies that such roof forms are suitable for buildings located in hot dry regions but not for those located in hot humid areas, and reasonably explains why curved roofs have been extensively adopted by builders and architects in the hot dry areas in the past. However, with the decrease in the half rim angle of a VR, the difference of indoor thermal condition between a VR and a FR building becomes small and insignificant. Results also indicate that the indoor air temperature is slightly influenced by the half rim angle _θ0${\theta }_0$ and the orientation _φv${\phi }_v$ of the VR. To be effective to create a favorable thermal condition inside buildings with a VR under hot dry climatic conditions, the half rim angle of a VR should be θ₀>50°, instead of _θ0<50^°${\theta }_0<50^{°}$, which is the optimal half rim angle of a VR of air-conditioned buildings, as found by the present authors in a previous study.     

Numerical analysis of the street canyon thermal conductance to improve urban design and climate

Built environment is increasingly dependent on the scientific knowledge which integrates urban design and climate. In the work presented here, the canyon thermal conductance which quantifies the heat transported outside of a canyon street, is analyzed to improve on understanding of how to accomplish this integration. A two-dimensional, steady, k$k$–ε$\epsilon$ turbulence model is used to study the influence of a windward heated wall on the air flow circulation in a street canyon with building height-to-street width ratio (aspect ratio) from 0.7 to 1.5. The numerical results presented here suggest that the air flow regime is strongly affected by buoyancy and three configurations are predicted: (I) and (II) with high Froude numbers (≈10¹$\approx {10}^1$) result in one or two stable counter-rotating vortices, with an intenser upper vortex; air flow regime (III), with low Froude numbers (≈10^-1$\approx {10}^{-1}$), is dominated by the lower vortex whose intensity is enhanced by a strong upward current close to the heated surface confining the upper vortex to a strict leeward zone of the canyon. Transitional Froude numbers are found as a function of canyon aspect ratio for transitions between regimes. The relevance of the results for urban design are quantified and analyzed in terms of canyon thermal conductance. The main conclusion is that, for one vortex skimming air flow regime, the canyon thermal conductance linearly increases with wind intensity, being larger streets more exposed to thermal losses. Multiple vortices in the air flow regime significantly decrease the canyon thermal conductance and, therefore, narrow streets provide protection from heat losses on windy and cloudy days and nights.     

Pollutant flushing with natural displacement ventilation

We examine the time taken to flush pollutants from a naturally ventilated room. A simple theoretical model is developed to predict the time taken for neutrally-buoyant pollutants to be removed from a room by a flow driven by localised heat inputs; both line and point heat sources are considered. We show that the rate of flushing is a function of the room volume, vent areas (A^*$A^{*}$) and the distribution, number (n) and strength (B  ) of the heat sources. We also show that the entire problem can be reduced to a single parameter (μ$\mu$) that is a measure of the vent areas, and a dimensionless time (τ$\tau$) that is a function of B, V   and μ$\mu$. Small-scale salt-bath experiments were conducted to measure the flushing rates in order to validate our modelling assumptions and predictions. The predicted flushing times show good agreement with the experiments over a wide range of μ$\mu$. We apply our model to a typical open plan office and lecture theatre and discuss some of the implications of our results.     

Statistical models for traffic noise at signalized intersections

A total of 14,235 noise levels measurements were utilized in developing statistical models that have the capability to predict different noise levels including: equivalent, maximum, or minimum noise level in terms of parameters affecting each level. Different parameters expected to have an effect on noise levels were collected. These parameters included traffic volume, composition of traffic, traffic speed, horn using effect, number of lanes, width of lanes, approach width, road slope, and pavement surface texture. The parameters affecting each noise level were selected based on simple correlation matrices, scatter plots, and statistical t$t$-test. Different forms of models were evaluated for each noise level. The best model describing the relationship between each noise level and parameters affecting it are presented in this paper. The reliability of the nonlinear developed models were judged based on coefficient of multiple determination (R²$R^2$), the significance of each variable at α$\alpha$-level of 0.05, and the standard error of the estimates. While the reliability of linear developed models were judged based on the general linear regression tests represented by F$F$-value and t$t$-value in addition to the coefficient of multiple determination (R²$R^2$), the significance of each variable at α$\alpha$-level of 0.05, and the standard error of the estimates.     

Interaction between the mixing and displacement modes in a naturally ventilated enclosure

Experiments are carried out to study for the first time interactive phenomena in buoyancy-induced natural ventilation in a full-scale enclosure with upper and lower openings on one of the sidewalls. The interaction between the mixing and the displacement ventilation modes is revealed by opening the lower vent to different heights while the upper vent is kept fully open. Both the transient process and steady state interaction are explored. Measurements include temperature differences between inside and outside and air velocity through the upper opening. The level of the neutral plane at the upper vent, defined here as the plane separating between inflow and outflow, decreases with R^*$R^{*}$, the ratio between the opening heights (and areas) of the lower and upper vents. Experiments show that when 0*<0.27$0<R^{*}<0.27$ the mixing and displacement modes interact through a new combined ventilation mode. For 0.53*?1$0.53<R^{*}?1$, the displacement mode dominates whereas in the intermediate range, 0.27?R^*?0.53$0.27?R^{*}?0.53$, either the combined or the pure displacement mode takes place. The experiments are in qualitative agreement with a previous theoretical model.     

Lighting monuments: Reflections on outdoor lighting and environmental appraisal

For more than 10 years, highlighting urban pattern, revealing the artifacts in our surroundings, and providing relationships among the elements of cities, outdoor lighting practice gained more significance. The following study aims at suggesting the needs for monument lighting, taking it as an essential architectural and outdoor lighting issue, and focuses on aspects to be considered both in the approach and application phases by discussing some examples from Ankara, the capital of Turkey. In order to determine approaches in attaining an effective lighting scheme, a case study was conducted. The participants were shown a series of photographs of the Bilkent University Atatürk Monument and its model taken under daylight and artificial lighting conditions, and the differences and tendencies in their perceptional preferences were examined. The results implied that lighting the monument with down-lighting technique is more preferable compared to up-lighting. The findings also suggested that there is no significant perceptional difference on the figure when daylight condition (direction) is imitated using artificial lighting sources. In the analyses, it was also observed that the difference in the incident angle (45^°${}^{°}$ and 60^°${}^{°}$) of light did not considerably change the perception of participants.     

The impact of urban street layout on local atmospheric environment

The investigation was carried out to reveal the impact of urban street layout on local atmospheric environment through computational fluid dynamics (CFD) numerical simulations using standard k$k$–ε$\epsilon$ turbulence model. Different street canyon configurations are considered and the flow regimes summarized according to the aspect ratio of the leeward building height and the street width H1/W$H1/W$ and the aspect ratio of the leeward building height and the windward building height H1/H2$H1/H2$. Three regimes are defined to denote the vortices and characteristics of pollutant dispersion in street canyons according to the parameters H1/W$H1/W$ and H1/H2$H1/H2$. It is found that the pollutant transport and diffusion is strongly dependent upon the type of flow regime inside the canyon and exchange between canyon and the above roof air. The study indicated that there is a strong influence of the street layout on the wind field and the pollutant dispersion in the street canyon mainly depends on the vortex structure in the canyon. The results are validated against an extensive wind tunnel experimental (Meroney and Rafailidis) [Journal of Wind Engineering and Industrial Aerodynamics, 1996;62:37–56; http://www.mi.uni-hamburg.de] and the simulated results concluded by Sini [Atmospheric Environment 1996;30:2659–77] and Sang [Atmospheric Environment 2002;36:1137–45].     

Determination of user profile at city parks: A sample from Turkey

A survey study conducted randomly in the cities of Erzurum, Erzincan and Kars included 360 subjects interviewed face to face. It was aimed to detect the subjective features of the participants such as gender, marital status, age, educational status and income level and the reflections of these features on the city parks. Conclusively, it was determined that those who are male, unmarried, at the age of between 19 and 24, university graduate and with a monthly income of 65–125 USD use the parks in majority. In the statistical analysis, the SPSS software was used and variables were compared. Chi-square (χ²) test was used to determine the independency correlations. According to the analysis, gender and income had no significant effect on the use of city parks, but marital status, age and education status had significant effects at 5% significance levels (*p<0.05$p<0.05$, χ²: 27.805; *p<0.05$p<0.05$, χ²: 44.073; *p<0.05$p<0.05$, χ²: 39.998, respectively).     

The effects of atmospheric exposure on the fracture properties of polymer concrete

In this experiment the effect of atmospheric exposure of epoxy and fiber-reinforced epoxy polymer concrete was investigated to evaluate its fracture properties, such as stress intensity factor, _KIc,$K_{\mathrm{Ic}},$ and fracture energy, _Gf$G_{\mathrm{f}}$. The deterioration and structural performance of polymer concrete were investigated in a real situation of exposure during a year period and compared the same formulation in laboratory conditions. The relationship between year period, exposure time and load-bearing capacity of deteriorated polymer concrete is studied and fracture mechanics of the specimens are discussed. From the tests results and discussion it is clear that the material studied, polymer concrete, suffers a high deterioration when subjected to aggressive environments.     

Evaluation of surface characteristics of laminated flooring

In this study, surface characteristics of commercially manufactured laminated flooring were evaluated. The surface roughness of samples consisting of high-density fiberboard (HDF) base and melamine resin saturated paper overlay was investigated. Here, 10 cm×10 cm samples of two types of panels were used for the experiments. A fine stylus technique was employed for the measurements. Three roughness parameters, namely average roughness (_Ra$R_{\mathrm{a}}$), mean peak to valley height (_Rz$R_{\mathrm{z}}$), and maximum roughness (_Rmax$R_{\max }$) were considered to determine roughness of the flooring panels. It was found that statistically significant difference existed between two types of samples as well as values taken along and across the sandmarks of the HDF and overlaid panels. Average _Ra$R_{\mathrm{a}}$, _Rz$R_{\mathrm{z}}$, and _Rmax$R_{\max }$ values for HDF were found as 2.73, 26.04, and 27.27 μm, respectively. Overlaid samples resulted in 15.6%, 26.0%, and 21.0% lower values of above parameters than those of HDF panels.     

Amenability of European silver fir (Abies alba Mill.) to preservative treatment by the full-cell process in longitudinal,tangential, radial and triplex flow pathways on the base of wood drying

This paper discusses the effects of wood drying upon treatability (as determined by preservative uptake and gain-in-weight retention) of European silver fir on the two moisture content (MC) levels which were designed to be above and below the fibre saturation point (FSP). The treatability behaviour was investigated for individual flow pathways: longitudinal (L$L$, along the stem), tangential (T$T$, along the growth rings) and radial (R$R$, along the rays), and also for the triplex (t$t$, cumulative of all three directions: all faces left open). As the FSP was observed 32.7%, MC of the experimental samples—for each flow path—nominated to around 50% and 9% by recommended kiln drying schedule using a conventional kiln. The samples were then treated with a 2.5% concentration of commercial Tanalith C of CCA (chromium/copper/arsenic) via a mild schedule of full-cell impregnation process using a model pressure treatment plant. Treatability of European silver fir was noticed in different behaviour in either flow paths before and after drying. According to the experimental results, MC regulate the preservative uptake (as the percentage of void volume filled with preservative, VVF%) along the grain (L$L$) and VVF% was improved by kiln drying process effectively, however, it was seemed to be contradictory across the grain (in both T$T$ and R$R$). In the cumulative form (t$t$), treatability—in either above or below the FSP—was appeared to be slightly greater than that for L$L$ due to support of the longitudinal flow. Therefore, it could be suggested that wood material which is subjected to be used in constructional purposes has to be initially dried to below the FSP, and—for efficient preservative treatment—it has to be treated with all faces unsealed (free from any pre-coating and/or painting). This shall be more ideal which in turn influences the quality of treated wood allowing better performance in its service life.     

Effect of machining on surface roughness of wood

The objective of this study is to evaluate effect of various machining techniques on the surface roughness of beech (Fagus orientalis) and aspen (Populus tremula  ) lumber. Surface characteristics of sawn, planed, and sanded samples of both species were determined employing a stylus type profilometer. Average roughness (_Ra$R_{\mathrm{a}}$), mean peak-to-valley height (_Rz$R_{\mathrm{z}}$), core roughness depth (_Rk$R_{\mathrm{k}}$), reduced peak height (_Rpk$R_{\mathrm{pk}}$), and reduced valley depth (_Rvk$R_{\mathrm{vk}}$) roughness parameters were used to determine surface characteristics of the samples. Based on the results of statistical analysis, measurements taken from the surface in tangential and radial directions of both species did not result in significant difference at a 95% confidence level. However, significant statistical difference was found between surface characteristics of aspen and beech samples, machined with four different ways in both grain orientations. This study suggests that stylus method can be successfully used to evaluate and distinguish variations on the surface of wood, due to grain orientation and planning and sanding. Data generated in this study can be used as a quality control tool for further processes such as finishing or gluing of wood from two species.     

Modeling thermal behaviors of window flame ejected from a fire compartment

A series of reduced-scale experiments were carried out in order to investigate thermal behaviors of window flame, which exposes the upper floors as well as the adjacent buildings to potential risks of fire spread. A stainless pan filled with alcohol was used as the fire source and was placed inside a cubic compartment of 900 mm side. Temperatures and velocities at various points inside and outside of the compartment were measured. The compartment was pressurized during the experiment by mechanically supplying air at several mass inflow rates through an inlet duct set at the bottom part of the compartment. This was for simulating fire conditions under the effect of external wind pressure. On the basis of the experimental observation, line (i.e., two-dimensional) heat source assumption was adopted for developing a model of window flame behavior. A dimensionless parameter Q^′*${Q^{\prime }}^{*}$ was derived from the governing differential equations in order to generalize the measurement results. Expressions for temperature rise along the trajectory ΔT_m and characteristic flame width b_T were developed incorporating the parameter Q^′*${Q^{\prime }}^{*}$.     

Scale model study of airflow performance in a ceiling slot-ventilated enclosure: Non-isothermal condition

Scale-model study of a non-isothermal ceiling slot-ventilated enclosure was investigated in both airspeed and thermal fields. Results of airflow pattern, centerline velocity and centerline temperature decay, velocity and temperature profile, airflow boundary layer and thermal boundary layer growth, floor velocity, and floor temperature difference were analyzed to establish semi-empirical prediction equations. Results also compared with previous researches to validate the physical behavior of air-jet. Data of centerline velocity decay showed similar airflow characteristics as isothermal air-jet with Archimedes number (Ar)<0.004$(\mathit{Ar})<0.004$, which performed as pseudo-isothermal airflow. Air-jet fell on entry with Ar>0.018$\mathit{Ar}>0.018$. A single circulation airflow existed at 0.004<Ar<0.011$0.004<\mathit{Ar}<0.011$ and two-circulation airflow occurred at 0.011<Ar<0.018$0.011<\mathit{Ar}<0.018$. The centerline velocity decay was fitted well as similar form of an isothermal condition. The centerline temperature decay was fitted well as the form of centerline velocity decay in both ceiling and floor regions. Both the velocity and temperature profiles agreed with results obtained from literature. Both airflow boundary layer and thermal boundary layer growths increased with traveling distance of air-jet. Maximum floor velocity and floor temperature difference were fitted well with different parameters. Analysis of airflow performance in a non-isothermal condition makes progress in predicting air quality inside the enclosures and guides the design concepts of ventilation system for an indoor environment.