ECOTEN – Identify and Mitigate Urban Heat Island

IDENTIFY AND MITIGATE URBAN HEAT ISLAND

Due to the increase in the number of inhabitants and global temperature in cities and the rapid spread of urban pollution due to transport, it has become necessary to take into account the bioclimatic aspect of managing cities.

ABOUT US

Company Profile

ECOTEN Smart Energy Solutions is an engineering firm based in Prague, Czech Republic. Our objective is to identify and mitigate the problem of urban heat islands and provide innovative solutions for energy efficiency in building and cities. For the past few years, we have dedicated ourselves to research and development activity related to the simulation of urban micro-climate.
  • We create thermal maps using satellite imagery and geographic informatics data, to locate the hottest neighborhoods.
  • We model urban neighborhoods with taking into account the materials used, the presences of vegetation and water and the weather conditions of the site.
  • We evaluate the comfort of spaces (air temperature, duration of sunshine, etc.) and the energy consumption of buildings.
  • We compare different urban scenarios and propose energy efficient solutions.

BACKGROUND

Urban Heat Island

Temperature Profile of an Urban Area subjected to Urban Heat Island

Urban heat island is characterized by higher temperature observed in cities as compared to the surrounding areas. There are several physical phenomena involved in its formation; including mineral constitution of cities and human activities such as automobile traffic and air conditioning. During the summer, this difference in temperature between cities and it’s surrounding can range up to several degrees. This can generate discomfort, even health risks, and high electricity consumption. As the temperature increases along with the number of people living in the cities, we need to find effective solutions to combat the harmful effects of urban heat islands.

IDENTIFICATION

Thermal Mapping

By processing data obtained from satellites placed in orbit around Earth by international space agencies, we can create a geographic map and extract the temperature distribution across an area. This way, it is possible to identify the hot and cold regions of a city and the areas where the phenomena of Urban Heat Island is prevalent. It is in this area that a bioclimatic treatment for urban design is required.

Thermal map of Paris the 19th of July 2016 (Temperature displayed are for information purpose. Factors not considered can give different values compared to real values)

MITIGATION

Micro-Climate Simulations in Urban Areas

With the help of specific technical tools, we can evaluate the impact of an urban design on the thermo-aeraulic comfort on that area or region, it's capacity to reduce urban heat island and the energy consumption of the buildings. For this we model the urban design in 3-D by taking into account parameters such as materials used, presence of vegetation, presence of water bodies, weather conditions of the site. There are several quantitative results which can be obtained from this model that are useful to address numerous urban issues.

Buildings Energy Consumption

A closed urban environment and the building design have a significant role to play in energy consumption of a building. In summer, depending on the uses of building, the electricity consumption due to air conditioning is a serious issue. By modeling the urban site, we can calculate the cooling needs of buildings and propose energy efficient building design.

Building in its Environment

Building in its Environment

Outdoor Comfort

A good design requires the reduction of urban heat islands and improvement of comfort level in public areas. With our simulations, we can evaluate several criterion such as air temperature, wind speed, humidity, solar radiation period used to study comfort of the urban environment. We can also calculate the universal thermal comfort index.

Surface Temperatures in Urban Area

Surface Temperatures in Urban Area

Wind Speeds Control

Newly constructed buildings in urban areas may result in the development of excess wind velocities. With our wind-analysis studies which we obtain from our model of a given urban neighborhood, we can evaluate the wind flow between buildings in that area. We can also calculate and obtain the average and maximum wind velocities flowing in that area.

Wind-Speed Analysis in Urban Area

Wind-Speed Analysis in Urban Area

Comparing Urban Design Scenarios

Air temperature at one point of the district, two scenarios

Air temperature at one point of the district, two scenarios

For developing an urban area, there are several designs which can be used. For each design, we can model and quantify the contribution of comfort and energy consumption. We can determine which designs or scenarios are more effective in terms of energy and comfort and also for the mitigation of urban heat islands. There are several strategies that we can employ in order to do this: White (Clear surface) Green (presence of vegetation) and blue (presence of water bodies). In the graph below , we can see that the temperature of the street is 2.5 °C more in the case with the presence of trees than the case with it’s absence.

Effects of Climate Change

Temperature evolution curves, low and high

Temperature evolution curves, low (RCP2,6) and high (RCP8,5)

The Intergovernmental Panel for Climate Change (IPCC) published a report on global warming. The report contains many scenarios for the evolution of global temperature during the 21th century. With the information provided in this report, we can estimate the consequent impact of climate change on a given area.

The Edge of Scientific Research

For operating the simulations of urban micro-climate, we use the calculation engine of Solene-Microclimat. It has been developed  by the research laboratory for urbanism in Nantes, France called "Centre de Recherche Nantais Architectures Urbanités" for over 10 years. It's most important characteristic is that it combines thermo-radiative model, computational fluid dynamics modes and thermal model of buildings and hence it is a powerful tool for analysis of urban micro-climate.

CLIENTS

Our service is configured and applicable for many types of clients.

  • City Officials and Urban Planners – Allows to create better living conditions for citizens through improved zoning, urban planning, and building design regulations. It is a tool for mitigating the urban heat island effect.
  • Electricity Producers – Allows better load forecasting, peak reduction and costs savings. Decreases costs for smart grid development.
  • Architect and Urbanist Agencies – Adds values to your project. Highlight their impact on the outdoor areas comfort and energy conservation.
  • Engineering Offices – Takes into account the urban environment for energy dynamic simulations. Perform CFD calculation in urban area.