The goal of the research is to predict the impact of urban morphological aspects on energy consumption by means of energy spatialization by studying the relationship between energy consumption and environmental parameters of the microclimate. Urban microclimate is influenced by various parameters such as urban forms and geometry, urban density, vegetation, water level and surface properties (Shishegar, 2013).
Statement of the Problem
For the increase in urban population, per capita energy consumption causes significant carbon emissions (Hossain & Hasanuzzaman). Very few studies have been done to find out the relationship between urban microclimate and urban morphology and its impact on energy consumption of Dhaka city.
Objective of the Research
Methodology
- Literature survey
- Field Study and Data Collection
- Simulation Study
- Sample Selection and Data Plotting for Analysis
A field survey was conducted to determine the existing energy consumption and microclimatic conditions on site. A photographic and observational field survey was conducted to determine the existing condition of these areas.
Quality Consideration
Internal Validity
External Validity
Reliability
Objectivity
Limitation
Some meters show low or zero electricity consumption due to the unit being empty or not being used by residents. Some meters show higher consumption of electricity due to guests or additional residents in the apartment unit in individual months.
Conclusion
The population of the city districts (thanas) and sub-districts (upazilas) in the Dhaka Metropolitan Area. Towards sustainable urban environment: an investigation into the relationship between electrical energy consumption and urban morphology in the context of Dhaka City.
Climatic Context of Dhaka region
From the average relative humidity graph, it can be seen that August, September and December are the more humid months, while February and March are the less humid months. In the warm period, the wind direction is from the south, mostly from the southeast.
Urban Microclimate
Urban Microclimatic Parameters
- Air Temperature
- Mean Radiant Temperature (MRT)
- Relative Humidity
- Wind Speed
Air temperature is one of the most important climatic parameters that directly affect thermal comfort (Rahman, 2015). MRT can affect air temperature and is an important factor for thermal comfort.
Urban Context of Dhaka region
Urban development of Dhaka city
Land Use
Population Density
Urban Area
- Urban Morphology
- Percentage of Built area and Open space
- Urban Street
- Canyon Ratio
For this research, 'micro domain' could be defined as the surrounding open area of the particular built form (building). The city streets in the planned area of Dhaka city are not always north-south or east-west oriented; rather, most of them are leaning at different angles.
Energy
Present Scenario of Energy Consumption and Distribution
33 for electricity generation Bangladesh Power Development Board (BPDB), Independent Power Producers (IPPs), Electric Generation Company of Bangladesh Ltd. EGCB), for transfer, Power Grid Company of Bangladesh Ltd. PGCB), for distribution, Bangladesh Power Development Board (BPDB), Dhaka Electric Supply Company Ltd. DESCO), Dhaka Power Division Company Ltd. DPDC), Rural Electrification Board (REB), West Zone Power Distribution Company Ltd. WZPDC), for the establishment phase, North Zone Power Distribution Company Ltd. NZPDC ), South Zone Power Distribution Company Ltd. SZPDC), Central Zone Power Distribution Company Ltd. South Dhaka was divided into three parts namely DPDC North, Central and South.
Use of Energy in Urban Areas
For electricity services, Dhaka city is divided into north and south parts where electricity is distributed by DESCO and DPDC.
Energy Spatialization
For example, Islam used inverse distance surface interpolation technique to find the spatial distribution of the temperature map and its trends to analyze the temperature changes over Bangladesh due to global warming (Islam). In this study, the author developed the spatial distribution maps of the mean value of daily maximum, minimum and mean temperature, and trends in Bangladesh (Islam).
Thermal Comfort
Green urbanism takes into account efforts to minimize the use of energy, water and materials at every stage of the city or district's life cycle, including the embodied energy in the extraction and transportation of materials, their manufacture and assembly of it in the buildings; and ultimately the efforts of green urbanism to value each individual building in the recycling phase, after their lifespan (Lehmann, 2011a). Architectural and urban development projects must take into account the use of primary energy for the operation of the district or building.
Conclusion
Environmental Monitor: Applications and Technology News for Environmental Professionals Retrieved June 5, 2015, from http://www.fondriest.com/news/airtemperature.htm. Paper presented at the International Seminar on Celebrating 400 Years of Capital Dhaka, Asiatic Society, Dhaka.
Methodology
This chapter broadly discusses the field survey, simulation and mapping conducted for the research. This chapter also explains study area identification, simulation configuration, simulation parameters, sample selection and energy spatialization mapping.
Field Study
The roads of the study area were made of asphalt and the sidewalks were made of concrete with brick borders and paving slabs. The population density of the houses in the study area was almost 4 persons per 200 m².
Selection of the Study Area
Although most of the plots in this area were residential, there were also schools, institutions, offices, shops and hospitals, etc. There are two main roads on the east and west sides of the area and two connecting roads on the north and south sides.
Samples Selection
Morphology of the Selected Area
Canyons oriented east-west and north-south were found in the selected samples.
Simulation: ENVI-met
Simulation
Average initial temperature (temperature at 6:00 a.m.), same-day wind speed, wind direction, and today's relative humidity have been used for the software's configuration file.
Simulation Parameters
Here the temperature, mean radiant temperature, relative humidity and wind speed range found from the simulation diagram are plotted for a quick overview. There was also variation in temperature and mean radiant temperature found at different times of the day.
Energy Spatialization Mapping: ArcGIS
Conclusion
61 Chapter four: Analysis and simulation study Introduction Methodology Microclimatic parameters Energy consumption Spatialization and microclimatic parameters Energy spatialization and urban morphology Conclusion of the comparative analysis. Again the spatial energy diagram for the study area is analyzed to find correlations with responsive urban morphology.
Methodology
The data, figure and graph obtained from field survey and simulation study were analyzed and discussed in this chapter. We discussed the spatial energy diagram and the microclimatic condition of the study area as determined by ENVI-met simulation and ArcGIS spatial mapping to draw a possible relationship.
Microclimatic Parameters
Energy Consumption
Energy Spatialization and Microclimatic parameters
- Energy Spatialization vs Temperature
- Energy Spatialization vs Mean Radiant Temperature
- Energy Spatialization vs Relative Humidity
- Energy Spatialization vs Wind Speed
The simulation image (Figure 4.5.f, Figure 4.5.g) of the microclimate and spatial energy map (Figure 4.5.h) shows that MRT has a great impact on the spatiality of energy. The microclimate simulation image (Figure 4.5.s, Figure 4.5.t) and the spatial energy map (Figure 4.5.u) show that wind speed has less impact.
Energy Spatialization and Urban Morphology
Energy Spatialization vs percentage of open spaces
78 Figure 4.6.b: Graph of percentage of open areas, MRT and energy consumption in April at 21:00. 80 Figure 4.6.h: Graph of the percentage of open areas, MRT and energy consumption in January at 9 p.m.
Energy Spatialization vs urban street
82 Figure 4.2.a: MRT and energy consumption of east-west and north-south elongated road in April. 83 Figure 4.2.d: MRT and energy consumption of east-west and north-south elongated road in January. It was found that MRT and energy consumption decrease moderately with the increase in canyon ratio.
Thus, the MET value of the north-south elongated street was found to be more than the east-west elongated street, which affects energy consumption and energy spatiality.
Energy Spatialization vs Canyon Ratio
Comparative Analysis
Conclusion
Observation on Microclimate and Energy Spatialization
The temperature in the study area was found to be higher than the average meteorological values in all seasons. The highest temperature was found at 15.00 and decreases at 21.00 in all months in the five times studied in the study area.
Observation on Urban Morphology and Energy Spatialization
It illustrates that the presence of a large percentage of open spaces causes the higher value of MRT and the higher energy consumption both during the day and at night. Solar radiation can penetrate more into the north-south elongated streets than the east-west elongated streets.
Findings
Higher value of canyon ratio means deep canyon which allows less solar radiation generating low MRT. Direct solar radiation hits city streets, footpaths, roads, building surfaces as well as other hard surfaces, which are responsible for high value of MRT and additional energy consumption.
Design Guideline
Design Guidelines: Percentage of Open and Built Space
Setback: The building set back of the study area is mostly of hard cobbles, which contributes to the increase in MRT. Urban green/urban roadside green: The amount of canopy shading determines the cooling effect of green spaces and trees (Shashua-Bar & Hoffman, 2000).
Design Guidelines: Urban Street
According to Shashua-Bar & Hoffman, approximately 80% of the cooling effect is contributed by tree shading during summer in their study area (Tel-Aviv urban complex, Israel) (Shashua-Bar & Hoffman, 2000). Therefore, the orientation, climate and microclimate of the location must be taken into account when designing a green area, implementing greening along the road and choosing plant species.
Design Guidelines: Canyon Ratio
The parking lot should be designed with soft paving, permeable sidewalks, sun protection and urban greenery. Soil, permeable cover, plants and a soft surface should be provided to absorb radiated heat in the release area.
Scope for Future Research
Investigation of aerodynamic characteristics of the urban context, a taxonomy of urban forms, the internal layout of the building can be included in future work.
Conclusion
Paper presented at the 2nd International Conference on ‘Sustainable Architecture and Urban Development 2010’ (SAUD 2010), organized by the Center for the Study of Architecture in the Arab Region (CSAAR), Amman, Jordan. Paper presented at the European Council for an Energy Efficient Economy (eceee) Summer 2005 Study report: What works & who delivers.
Details of the selected samples
Road side large plants on the east side and small plants on the south side. Road side large plants on the south side and small plants on the east side.
Questionnaire Survey Form
Letter to the Director Operation, DPDC
Sample calculation process of electricity consumption
Here the electricity consumption of the month in question is calculated based on the total electricity consumption/the total square meters covered by the electricity. For some units a '0' or very minimal electricity consumption (0-50) has been determined in the month in question. These were not taken into account in the calculation for that month.
Electricity consumption data of all smaples
