Optimum Form and Placement of Urban Blocks to Maximize the Use of Solar Energ – a Case Study (original) (raw)
OPTIMUM FORM AND PLACEMENT OF URBAN BLOCKS TO MAXIMIZE THE USE OF SOLAR ENERGY – A CASE STUDY
Growing tendency for Urbanization and rapid development of the cities has resulted in urban neighborhoods obstructing the access of each other to the natural sources e.g. solar energy, natural ventilation. Sunlight as the main part of input energy in urban energy balance equation and natural lighting is of vital importance. This paper attempts to achieve an optimum morphology for residential blocks in urban area with the highest exposure to the sunlight. To reach this goal a pilot area in Tabriz's downtown was selected and regarding solar angle, local street regulations and the width of surrounding streets 3 different scenarios for the buildings blocks were defined. Using a three-dimensional microclimate model, ENVI-met, solar access of defined scenarios was calculated for the longest and the shortest day of the year. Results showed that Type C2 (highest, more open spaces) is a more efficient style for winter times as it receives more of the sun's energy and also the amount of sun it gets during a day and type B2 (medium open space and height) is the better for summer as it gets less energy from the sun and it is exposed to sunlight less than other types in a hot summer day.
Environmental Science and Sustainable Development, 2022
Increasing population causes Energy consumption and environmental pollution. It is essential to consider renewable forms of energy, especially solar power, to reduce energy consumption. This requires attention to energy issues in the early stages of urban design and practical and creative solutions for more efficient use of this type of energy. This study aims at calculating the annual solar radiation at a city scale through a novel process and methodology. In this regard, artificial intelligence algorithms and satellite data can help maximize the amount of sunlight in neighborhoods and urban blocks in neighborhood units during the development process. In the simulation process, location, and optimization of the urban form, it is necessary to consider the limitations and resources for field study and simulation of urban blocks. Therefore, in this study, Farhangian neighborhood in phase 1 of Kermanshah, Iran, which has a good level of structural diversity and lends itself to field studies, was selected and studied at neighborhood and urban block scales. The case study indicates the significant role of calculating and optimizing the patterns of urban blocks to achieve maximum solar energy. Estimates at different levels show that urban block variables effectively access solar radiation energy and, given various scales of development-from macro-scale spatial planning to micro-scale local design-can improve energy intake by 3 to 5 percent. Accordingly, the results show that to accelerate the calculation of energy at the planning scale, the use of 2.5D locating model and 3D optimization contribute to achieving the maximum or minimum solar radiation, respectively. On the other hand, this method can be used to organize calculations and planning for maximum absorption of solar radiation at different stages of development.
Urban and Transit Planning
It has been proven that designing sustainable buildings starts from early stages of urban design. The design of urban blocks, specifically, is deemed one of the pragmatic approaches of sustainable urban design. Studies have focused on the impact of urban block design and regulation on the outdoor thermal comfort in the semi-arid regions. However, limited studies have been found in the semi-arid regions, which examined that impact, on the indoor behaviour of buildings (specifically, the daylight quality and energy performance). Further, heating load is neglected in most studies of the semi-arid regions in which the focus is only on the cooling load reduction. The study has focused on two parameters of urban block distribution, which are the surface-to-volume ratio of blocks and their orientation with the consideration of both heating and cooling loads of buildings. In Duhok (a semi-arid city in the Kurdistan region of Iraq), daylight quality and energy consumption of various types of residential blocks have been observed using dynamic simulation. The results propose that there is a substantially higher energy demand for heating than cooling, providing attention to the heating load in semi-arid regions. Reasonably, because of the high U-values of buildings in Duhok. The findings also suggest that changing blocks' orientation can alter the total energy consumption by 8%. With regards to the surface-to-volume ratio (S/V), an increment of 15% of overall energy consumption is noticed after doubling the ratio (S/V), though the research reveals the opportunity of decreasing energy consumption with the rise of the S/V through passive design strategies of urban blocks. Based on the results, recommendations are given for revising the design of current/future residential urban blocks to maximise indoor daylight quality with a higher S/V and more energy saving in these regions.
A Methodology for Buildings Access to Solar Radiation in Sustainable Cities
Sustainability, 2019
The growing need to improve the environmental and energy sustainability of buildings involves the use of solar radiation incident on their surfaces. However, in cities, this task is complicated due to the constructive geometry that leads to shading between buildings. In this context, this work presents a study of solar access to the façades of buildings in cities. The methodology is based on the determination of the incident annual solar radiation in 121 significant points of each façade considering the twelve representative days of the year. To characterize the influence of the different city typologies on solar access, the urban solar coefficient is proposed. A study of two neighborhoods in Cordoba (Spain) with different urban settings have been analyzed. Specifically, two typologies of neighborhoods have been compared: one with "L-shaped" and "U-shaped blocks" and another with "Grouped blocks". For both of them, the Urban Solar Coefficient has been calculated, obtaining a higher mean value for the neighborhood with "L-shaped" and "U-shaped blocks" (0.317) than for the one with "Grouped blocks" (0.260). Accordingly, the results show that urban morphology can influence the Urban Solar Coefficient and solar access. Finally, a regression model for each neighborhood has been obtained in order to determine the dependence of the Urban Solar Coefficient on neighborhood geometry factors.
The clear and persistent threat of climate change urges mankind to charter a direction towards a low carbon society. The " 2 Kilowatt society " as a vision of a low carbon society requires substantial commitment from the developed nations of the world. Western Europe consumes 4-6Kw/cap of primary energy and substantial efforts are needed to reduce this energy consumption (Winter C.J. 1993). Development of Renewable energy resources is extremely crucial to achieve this target and solar energy is regarded as one most appropriate technology available to achieve a low carbon future. According to the European Commission about 13%-20% of primary energy requirements of its 12 members can be met by passive utilization of solar energy for thermal and lighting needs of domestic and non domestic building stock. In West Germany 1000K/ m² of aggregate wall and roof area is available with southern exposure which has a potential power generation capacity of 100 tetra watt-hours which is equivalent to 25% of the annual electricity production in 1980's (Winter C.J. 1993). Passive solar design can have substantial energetic benefits both at the demand and supply side of energy consumption spectrum. In UK Passive solar homes, without using active solar collectors, can reduce heating energy consumption up to 2000 kWh/annum compared to conventional housing (ETSU figures, Littlefair PJ 2002). Considering this huge photovoltaic potential, designing cities to access light and heat from the sun seems to be a logical decision. Urban design and planning as form givers of cities play a vital role in realizing this tremendous energetic potential of urban form. Respecting solar access for day lighting and passive heating has been a standard norm for urban design in many cities like Los Angeles or San Francisco. Traditional settlements like the Pueblos of Mesa Verde, Colorado demonstrate a remarkable ability to utilize solar energy by establishing a relationship between the sun path and urban form. Sustainable master planning today is the norm rather than an exception and planers have several sophisticated decision support tools and policies available to their disposal. Energy concerns are even better addressed today especially at the building level through strict building design codes for application of passive solar design through use of sunspaces, advanced glazing, solar thermal collectors, heat pumps and photovoltaic building shells. Research and strict monitoring has resulted in design efficiency at both the ends of the development spectrum. However, a grey area still exists where Urban Planning guidelines and building regulations overlap, especially at the urban block level where neither planning nor building design regulations are effective. The morphology of the urban block has been shaped traditionally by issues like land use, transportation and finance which became more relevant at this scale than the architecture of energy efficiency. However climate change has allowed the planners and urban designers to reinvent the contemporary city and with it, it's constituent-the urban block. An environmental approach of designing the low energy urban block is a prerogative and needs to be addressed through innovative design guidelines. The 'Solar Envelope Concept' introduced by Knowles (Knowles, 1981, MIT) explores this relationship of energy with urban form and can form the basis of solar access guidelines for Urban blocks. 2.0 The solar envelope: 2.0.1 Theory and construction The " solar envelope " defines the maximum limits of a three-dimensional buildable volume on a given site that does not obstruct more than any pre defined hours of solar access onto adjacent sites and buildings. As a concept, urban blocks designed as solar envelopes will allow maximum photovoltaic potential for the adjacent buildings. The concept can be extended to " Iso Solar Rights Envelopes " and " Iso Solar Collector Envelopes " (Shaviv E. et al 2005) which allow maximum mutual solar potential for an escalating scale ranging from a building, parts of a building, an urban block to a full city shaped to harness solar energy. " Solar Rights Envelope " (SRE) is the maximum building volume that does not violate the
Indoor and Built Environment, 2016
The research project carried out aimed to establish guidelines for urban design, especially adjusted to specific climatic conditions and to local design practice. With the aid of a simulation program, Townscope III, several urban scenarios were characterized in what concerns solar access. Some results are presented for the specific case of a block in Espinho. Four different building models were tested. Solar access was evaluated and its repercussion on heating and cooling energy needs of the buildings was estimated. A virtual scenario with an increase of the density of the urban surrounding area was also assessed.
Buildings are responsible for around 40% of world energy use and residential buildings as an important sector consumes a significant part of this energy. The main part of the energy used in residential buildings is consumed for space heating, cooling and lighting. Solar energy as an important constituent of climate could be utilized passively for heating and cooling living spaces and providing daylight. Designing residential blocks could affect the amount of solar radiation received by inside and outside the buildings. It is assumed that orientation, residential block form and landscaping are the main design factors which determine the optimum use of solar energy and hence the need for space heating or cooling of buildings by conventional energy sources. This paper aims to study the impacts of orientation, form and landscaping on solar access in order to find the optimal residential block configuration that benefits solar conditions and provides as much solar irradiation in colder seasons and shade in warmer seasons. In this regard, the current literature and evidence are reviewed. The results of these studies indicate that proper passive solar design should consider orientation, form and landscaping as key buildings' parameters in order to provide enough solar access in different seasons.
Journal of Physics: Conference Series, 2021
This study discusses the interplays between urban form and energy performance using a case study in Singapore. We investigate educational urban quarters in the tropical climate of Singapore using simulation-based parametric geometric modelling. Three input variables of urban form were examined: street network orientation, street canyon width, and building depth. In total, 280 scenarios were generated using a quasi-Monte Carlo Saltelli sampler and Grasshopper. For each scenario, the City Energy Analyst, an open-source urban building energy simulation program, calculated solar energy penetration. To assess the variables' importance, we applied Sobol' sensitivity analysis. Results suggest that the street width and building depth were the most influential parameters.
Solar Energy as a Design Parameter in Urban Planning
Energy Procedia, 2012
By the end of 2020, all EU member states need to ensure that all newly constructed buildings consume 'nearly zero' energy and that their energy needs are produced locally as much as possible and with renewable sources; a concept called nearly Zero Energy Buildings (ZEB). At the same time, more and more people live in cities, where the access to local renewable energy sources -wind and solar-is limited. Planning for such ZEBs in cities is therefore a difficult task since urban planners often do not have the technical knowledge to quantify the contribution of solar energy in their urban plans. This study shows an exploration of geometrical forms of urban blocks and the potential of solar energy to the local production of energy. Simulations were performed with the program Ecotect for the city of Lund in southern Sweden. It was found that the impact of the geometry form on the potential of solar energy was significant (up to twice as much) and some forms were found to be less sensitive for different orientations. When the urban blocks were surrounded by other geometry, which resembles the situation of a dense city, the contribution of solar energy decreased by 10-75%.