Building Aspect Ratio Research Articles

Impact of Building and Refrigeration System’s Parameters on Energy Consumption in the Potato Cold Storage

Cold storage is a key element for long term preservation and distribution of perishable items. A large quantity of perishable items is gone wastage every year due to inadequate storage facility in the countries like India. Their energy extensive refrigeration process makes them accountable for substantial share of total energy consumption in the country. Moreover, energy inefficiency in operation and building designs in the existing cold storages inhibits expansion of desirable storage facility. This study aims to explore the building and refrigeration system’s parameters that may influence the overall energy consumption in the storage. A survey was conducted in ten Indian potato cold storages and detail data of their energy consumption, building construction and refrigeration systems was collected. The collected data was analyzed quantitatively and qualitatively. Trend analysis technique was also used to establish relationship between specific energy consumption and identified parameters. Results show that the utilization factor has major impact on the energy consumption in the storages and the existing cold storages are not utilizing their storage capacities fully. Comparatively higher energy consumption was observed in the cold storages that have low utilization factors. Building aspect ratios and effective U-value of the building envelop were also identified one of the crucial parameters that can play a major role to improve the energy performance of the cold storages. As expected, a negligible variation in the specific energy consumption of the storages with the specific installed refrigeration systems and AHUs was observed.

Solar potential in urban residential buildings

This paper investigates solar potential in urban residential buildings at low, medium and high levels of site densities. The effects of three major design parameters (i.e. building aspect ratio, azimuth and site coverage) on solar potential are evaluated, respectively. Solar potential is measured, respectively, by photovoltaic (PV) and solar thermal (ST) yields per building floor space, taking into account the effect of irradiation threshold and incidence angle of the Sun’s rays. The results show that increasing building aspect ratio tends raise solar potential, and so does increasing site coverage. Additionally, there is a preferred range of building azimuth, under which PV yield remains at a higher level and out of which PV yield plummets. However, ST yield is affected modestly by building azimuth. This study also reveals that while mutual shadings may decrease PV yield by up to 50% and ST yield by up to 26% in the high-density scenario, it is still possible for PV and ST yields to meet annual electrical and thermal demands of residential buildings, respectively, by selecting appropriate design parameters. Most importantly, a promising result is observed that 6-story buildings in the low-density scenario can achieve net zero energy status when considering combined use of PV and ST.

The Effect of Building Aspect Ratio on Energy Efficiency: A Case Study for Multi-Unit Residential Buildings in Canada

This paper examines the energy consumption of varying aspect ratio in multi-unit residential buildings in Canadian cities. The aspect ratio of a building is one of the most important determinants of energy efficiency. It defines the building surface area by which heat is transferred between the interior and exterior environment. It also defines the amount of building area that is subject to solar gain. The extent to which this can be beneficial or detrimental depends on the aspect ratio and climate. This paper evaluates the relationship between the geometry of buildings and location to identify a design vernacular for energy-efficient designs across Canada.

DETERMINING THE EFFECT OF BUILDING GEOMETRY ON ENERGY USE PATTERNS OF OFFICE BUILDINGS IN TORONTO

The project investigated the potential of building geometry to minimize energy consumption in office buildings. Five distinct geometries were modeled as mid-size office occupancies in the context of Toronto, Ontario, and examined with varied design parameters: window to wall ratio (WWR) and external static shading devices. IES VE software was used to predict the annual energy consumption of the five archetypes for 40 permutations. The outcome of this research showed that the variation of the total energy use from one shape to another was relatively small. WWR appeared to have a stronger impact on the energy pattern of a building than its shape. Overall, the energy performance of the archetypes were observed to conform to their individual building aspect ratios. The findings are thus expected to provide useful guidelines for architects on utilizing building geometry as an energy saving measure in the design of office buildings.

Seasonal dependence of the urban heat island on the street canyon aspect ratio

In this article we study the relation between the urban heat island (UHI) in the urban canyon and street geometry, in particular the aspect ratio. Model results and observations show that two counteracting processes govern the relation between the nocturnal UHI and the building aspect ratio: i.e. trapping of long‐wave radiation and shadowing effects. In general, trapping of long‐wave radiation supports the UHI, whereas shadowing effects reduce the UHI. The net effect depends on the UHI definition and the amount of available short‐wave radiation penetrating the canyon. In summer, autumn and spring the shadowing effects can already reduce the UHI starting at an aspect ratio between 0.5 and 1. The analysis is carried out using several methods. Firstly, the single‐column model version of the Weather Research and Forecasting (WRF) model is used extensively. Two separate runs, one rural and one urban, are used to estimate the UHI. Secondly, the urban canyon temperature at the 2 m level is introduced, which allows for direct comparison between modelled and observed air temperatures within the urban canyon. Finally, the model is evaluated for all four seasons. The results of this research provide important insights for urban planning on how to use the aspect ratio to mitigate the UHI in the urban canyon.

3D-Analysis of Soil-Foundation-Structure Interaction in Layered Soil

The analysis of building structure in contact with soil involves an interactive process of stresses and strains developed within the structure and the soil field. The response of Piled-Raft Foundation system to the structure is very challenging because there is an important interplay between the component of building structure and the soil field. Herein, soil-foundation-structure interaction of buildings founded on Piled-Raft Foundation is evaluated through 3D-Nonlinear Finite Element Analyses using PLAXIS3D FOUNDATION code. The soil settlements and forces demand of the high-rise building structures and foundation is computed. The parametric study affecting the soil-foundation-structure response has been carried out. The parameters such as construction phasing, sequential loading, building aspect ratios, soil failure models and thickness proportion of soil field stiff layer, are considered. It is concluded that the interaction of building foundation-soil field and super-structure has remarkable effect on the structure.

Effect of Early Solar Energy Gain according to Building Size, Building Openings, Aspect Ratio, Solar Azimuth, and Latitude

AbstractThis study determines the effects of building openings, size, proportions, orientation, and latitude with regard to the needed energy to keep interior spaces within the comfort zone. For this analysis, the average temperatures throughout the year and average daily temperature swings at five different locations are applied, indicating the effect of exposure to morning direct radiation, which is considered early solar energy, versus noon and afternoon, and the potential energy gain from optimized orientation of buildings. Data such as temperature values are assigned to the anticipated average based on collected data. Depending on latitude and local climate, it is evident that minor angle shifts in building orientation may produce noticeable results in terms of energy gain or block at different times of the day. Adjustments on proportions and azimuth contribute toward a rate of solar energy gain that corresponds better to the building needs for thermal energy at different times of the day.

Wind Tunnel Tests for Wind Pressure Distribution on Gable Roof Buildings

Gable roof buildings are widely used in industrial buildings. Based on wind tunnel tests with rigid models, wind pressure distributions on gable roof buildings with different aspect ratios were measured simultaneously. Some characteristics of the measured wind pressure field on the surfaces of the models were analyzed, including mean wind pressure, fluctuating wind pressure, peak negative wind pressure, and characteristics of proper orthogonal decomposition results of the measured wind pressure field. The results show that extremely high local suctions often occur in the leading edges of longitudinal wall and windward roof, roof corner, and roof ridge which are the severe damaged locations under strong wind. The aspect ratio of building has a certain effect on the mean wind pressure coefficients, and the effect relates to wind attack angle. Compared with experimental results, the region division of roof corner and roof ridge from AIJ2004 is more reasonable than those from CECS102:2002 and MBMA2006.The contributions of the first several eigenvectors to the overall wind pressure distributions become much bigger. The investigation can offer some basic understanding for estimating wind load distribution on gable roof buildings and facilitate wind-resistant design of cladding components and their connections considering wind load path.

テラスハウス周辺の緑被率と周辺気温低減効果に関する定量的把握

The aim of this study is to investigate environmental situation surrounding terraced houses with greenery patterns, and to accumulate objective data and features in the new developed residential area in Malaysia. A computer microclimate simulation technique is applied by combining stored digital spatial data on GIS as main tools. As a results, i) There is almost no temperature changes between the current building shape and after changing the building aspect ratio without additional greening. However after green space added, some contributions for reducing surrounding temperature can be observed. ii) The relatively higher cooling effects of greenery in the surrounding building and block can be observed in the afternoon and evening. iii) Increasing approximately 11% green coverage ratio make effects of reducing about 0.5°C above the green spaces and about 0.3°C on the surrounding area.

Effects of building aspect ratio, diurnal heating scenario, and wind speed on reactive pollutant dispersion in urban street canyons

A photochemistry coupled computational fluid dynamics (CFD) based numerical model has been developed to model the reactive pollutant dispersion within urban street canyons, particularly integrating the interrelationship among diurnal heating scenario (solar radiation affections in nighttime, daytime, and sun-rise/set), wind speed, building aspect ratio (building-height-to-street-width), and dispersion of reactive gases, specifically nitric oxide (NO), nitrogen dioxide (NO2) and ozone (O3) such that a higher standard of air quality in metropolitan cities can be achieved. Validation has been done with both experimental and numerical results on flow and temperature fields in a street canyon with bottom heating, which justifies the accuracy of the current model. The model was applied to idealized street canyons of different aspect ratios from 0.5 to 8 with two different ambient wind speeds under different diurnal heating scenarios to estimate the influences of different aforementioned parameters on the chemical evolution of NO, NO2 and O3. Detailed analyses of vertical profiles of pollutant concentrations showed that different diurnal heating scenarios could substantially affect the reactive gases exchange between the street canyon and air aloft, followed by respective dispersion and reaction. Higher building aspect ratio and stronger ambient wind speed were revealed to be, in general, responsible for enhanced entrainment of O3 concentrations into the street canyons along windward walls under all diurnal heating scenarios. Comparatively, particular attention can be paid on the windward wall heating and nighttime uniform surface heating scenarios.

Optimum lateral load pattern for seismic design of elastic shear‐buildings incorporating soil–structure interaction effects

SUMMARYRecently, several new optimum loading patterns have been proposed by researchers for fixed‐base systems while their adequacy for soil–structure systems has not been evaluated yet. Through intensive dynamic analyses of multistory shear‐building models with soil–structure interaction subjected to a group of 21 artificial earthquakes adjusted to soft soil design spectrum, the adequacy of these optimum patterns is investigated. It is concluded that using these patterns the structures generally achieve near optimum performance in some range of periods. However, their efficiency reduces as soil flexibility increases especially when soil–structure interaction effects are significant. In the present paper, using the uniform distribution of damage over the height of structures, as the criterion, an optimization algorithm for seismic design of elastic soil–structure systems is developed. The effects of fundamental period, number of stories, earthquake excitation, soil flexibility, building aspect ratio, damping ratio and damping model on optimum distribution pattern are investigated. On the basis of 30,240 optimum load patterns derived from numerical simulations and nonlinear statistical regression analyses, a new lateral load pattern for elastic soil–structure systems is proposed. It is a function of the fundamental period of the structure, soil flexibility and structural slenderness ratio. It is shown that the seismic performance of such a structure is superior to those designed by code‐compliant or recently proposed patterns by researchers for fixed‐base structures. Using the proposed load pattern in this study, the designed structures experience up to 40% less structural weight as compared with the code‐compliant or optimum patterns developed based on fixed‐base structures. Copyright © 2012 John Wiley & Sons, Ltd.

Analysis of airflow over building arrays for assessment of urban wind environment

Large eddy simulation (LES) of the airflows around various types of block arrays was performed to estimate the pedestrian wind environment. Five types of uniform staggered block arrays with different aspect ratios and an array with a nonuniform height were selected for the simulations. The simulation accuracy was validated by comparing the drag coefficient and wind profiles with those of previous work. The characteristics of the spatially averaged mean wind profiles of the arrays were analyzed on the basis of the calculation results. This study reveals that the frontal area ratio, which is the product of the plan area ratio and building aspect ratio, is the most important parameter in estimating the pedestrian wind environment. In addition, a simple exponential equation was derived for predicting the pedestrian wind speed as a function of the frontal area ratio, which is applicable to various building aspect ratios and amounts of height variability.

Numerical Simulation of the Surface Air Temperature Change Caused by Increases of Urban Area, Anthropogenic Heat, and Building Aspect Ratio in the Kanto-Koshin Area

Numerical Simulation of the Surface Air Temperature Change Caused by Increases of Urban Area, Anthropogenic Heat, and Building Aspect Ratio in the Kanto-Koshin Area

A performance-based method for energy efficiency improvement of buildings

Building energy standards provide control over excessive use of energy in buildings, promoting energy efficiency and mitigating detrimental environment impacts brought by high energy consumption. The central objective of this paper is to develop correlations that will predict building heat gains and cooling energy consumption for commercial buildings in tropical climates. The energy performance index OTTV was first revised to obtain a new performance index, ETTV for commercial buildings. We developed new correlations to investigate the impact ventilation rates and building aspect ratios had on building cooling energy consumption. Comparing estimated and simulated results, we demonstrated good agreement, even for buildings having different aspect ratios. A study was further conducted to investigate the impact of weather conditions on the developed methodology for estimating the energy consumption of buildings. We employed a design-day weather file to provide simplicity, flexibility and greater ease of use. The design day concept is pivotal in providing key inputs to the cooling energy-estimating methodology yielding good agreement with DOE-2.1E simulated results. We believe that the results presented in this study will benefit building authorities in their pursuit of developing and refining stringent building energy standards in order to realize better energy efficient buildings.

On the heating environment in street canyon

This study investigates the impact of building aspect ratio (building-height-to-street-canyon-width-ratio), wind speed and surface and air-temperature difference (Δθs−a) on the heating environment within street canyon. The Reynolds-averaged Navier-Stokes (RANS) and energy transport equations were solved with Renormalization group (RNG) theory version of k-\({\varepsilon}\) turbulence model. The validation process demonstrated that the model could be trusted for simulating air-temperature and velocity trends. The temperature and velocity patterns were discussed in idealized street canyons of different aspect ratios (0.5–2.0) with varying ambient wind speeds (0.5–1.5 m/s) and Δθs−a (2–8 K). Results show that air-temperatures are directly proportional to bulk Richardson number (R b ) for all but ground heating situation. Conversely, air-temperatures increase significantly across the street canyon with a decrease in ambient wind speed; however, the impact of Δθs−a was negligible. Clearly, ambient wind speed decreases significantly as it passes over higher AR street canyons. Notably, air-temperatures were the highest when the windward wall was heated and the least during ground heating. Conversely, air-temperatures were lower along the windward side but higher within the street canyon when the windward wall was heated.

Effects of building aspect ratio and wind speed on air temperatures in urban-like street canyons

The objective of this study is to simulate the characteristic role of building aspect ratio (AR) and wind speed on air temperatures during different street canyon heating situations. A two-dimensional Renormalization Group (RNG) k– ɛ turbulence model is employed to solve the Reynolds-averaged Navier–Stokes (RANS) and energy transport equations. A comparison of the results from the adopted model with those reported by similar experimental and numerical works demonstrated that the model is quite reliable when simulating temperature and wind profiles. The model is employed to predict air temperatures in idealized street canyons of aspect ratios (building-height-to-street-width ratio) of 0.5–8 with ambient wind speeds of 0.5–4 m/s. Three situations were identified for simulating diurnal heating of street canyon. It is noted that air temperatures are positively correlated with the bulk Richardson number ( R b) in most of the cases. The results show that the air temperature difference between high and low AR street canyon (Δ θ AR) was the highest during the nighttime (i.e., around 7.5 K between AR8 and AR0.5), but low or even negative during the daytime. It is also found that air temperatures rose as high as 1.3 K when ambient wind speed decreased from 4 m/s to 0.5 m/s. It is also revealed that the Δ θ AR during different diurnal situations and the nighttime and daytime air temperature difference between urban and rural areas (Urban Heat Island, UHI) closely resemble one another. Conclusively, the results of this study have highlighted the importance of street canyon AR and wind speed on urban heating.

Analysis of urban heat island effect using an improved CTTC and STTC model

An improved cluster thermal time constant (CTTC) and surface thermal time constant (STTC) numerical model was introduced, which took into account the effect of vegetation coverage and modified the expression of net long-wave radiation of the canyon layer. In the case study the model was used to calculate the air temperature variation at downtown of Tianjin City. The relative error between the calculated and measured air temperatures was less than 3%. The tendency of air temperature variation was predicted when the building aspect ratio, vegetation rate, and wind speed changed respectively. It is demonstrated that when the aspect ratio of a building with south-north orientation increased, the heat island intensity at day time was mitigated; however, it became worse after sunset. The vegetation coverage rate and wind speed both had negative relationship with the urban heat island intensity.

Impact of building shape on thermal performance of office buildings in Kuwait

This paper provides a simplified analysis method to estimate the impact of building shape on energy efficiency of office buildings in Kuwait. The method is based on results obtained from a comprehensive whole building energy simulation analysis. The analysis takes into account several building shapes and forms including rectangular, L-shape, U-shape, and H-shape as well as building aspect ratios, window-to-wall ratios, and glazing types. The simplified method is suitable for architects during preliminary design phase to assess the impact of shape on the energy efficiency of office buildings.

Thermal performance optimization of building aspect ratio and south window size in five cities having different climatic characteristics of Turkey

The aim of the study is to establish optimum building aspect ratios and south window sizes of residential buildings from thermal performance point of view. The effects of 6 different building aspect ratios and eight different south window sizes for each building aspect ratio are analyzed for apartments located at intermediate floors of buildings, by the aid of the computer based thermal analysis program SUNCODE-PC in five cities of Turkey: Erzurum, Ankara, Diyarbakir, Izmir, and Antalya. The results are evaluated in terms of annual energy consumption and the optimum values are driven. Comparison of optimum values and the total energy consumption rates is made among the analyzed cities.

Effect of orientation on thermal performance of a building

The effect of aspect ratio and orientation of a non-airconditioned building on its thermal performance has been analysed in terms of discomfort index for hot-dry and composite climates. It is shown that the discomfort index for east-west orientation is smaller than that for north-south orientation but the difference even for the largest aspect ratio considered is not more than 10%.