Cool City

Urban design from an engineering perspective
Against the background of aging society and the globalization, there is a rising need for urbanization that aggregates scarce resources and performs efficient economic activity. On the other hand, the creation of pleasant and comfortable public spaces suitable for mature cities has become the new task, alongside the environmental problems caused by urbanization. As a solution for these issues, creating a “Cool City” that designs air, water, light, and heat from an engineering perspective would contribute to a sustainable society.

Using Engineering Ability to Address the Environmental Problems of Urbanization

Simulation of wind countermeasures for a large-scale development
Optimizing the vegetation layout mitigates the incidence of strong winds

Mitigating winds with building shape and vegetation

Environmental problems caused by urbanization include the heat island effect and building winds. The impacts of these phenomena can now be forecast in detail using simulation of CFD etc. Impact on the environment can be predicted, and effective countermeasures can be implemented by applying engineering theory.
For example, in a district development that includes multiple tall buildings, wind tunnel testing and simulation that includes the surrounding area can provide a grasp of the wind environment in that areas. Solutions for resulting areas of strong wind, such as changing the shapes and placement of buildings, can then be studied. The effects of measures can be validated through more detailed simulations before they are implemented, in order to apply more effective measures with greater accuracy than was possible before.

Use Wind, Air, Water, and Light to Design for Amenity in Public Spaces

A proposal for the “Metropolitan Compost” international competition (site landscaping with scenic water and abundant greenery)

“Green Legacy” cool spot proposal

The creation of public spaces with diverse values is needed as one of the elements of a mature city. Such public spaces are usually built in outdoor or semi-outdoor spaces, so the adjustment of the light and heat environment needs to be done with natural energy, rather than using the artificial lighting and air conditioning that would be used for indoor spaces. Complex combinations of wind, air, water, and light should be designed totally to suit high-quality public spaces.

Microclimate Design in Cool City

This project proposes an outdoor public space design with methods to keep occupants cool such as insolation control by shading, equipment that directs breeze, dry water mist and other technologies suitable for outdoor environments.

Visualization of water absorbing performance of the non-woven cloth. Red indicated high water content. The water-raising performance of non-woven cloth depends on the structure of the fabric.

Example of use of non-woven cloth

Illustration of application in an outdoor environment. Radiant effects due to surface temperature reduction and evaporative cooling enables the supply of cool air movement.

Smart dry water mist
This system uses dry water mist to cool air or ground surface according to occupancy.

Outdoor space design chart

Examining quantitative performance of each strategy for design of outdoor space.

Conditions of COOL TREE CFD analysis

CFD analysis was used to calculate physiological quantities of human body models and cooling effects under the COOL TREE.

Result of CFD analysis

The skin surface temperature of the body models in proximity to the COOL TREE for two minutes dropped and the WBGT of surrounding air dropped to 28°C or lower.

Heat balance between the surface (skin) of the human body and its environment

A heat dissipation effect of 110W to 120W was observed due to the dry water mist system.

From Buildings to a “Cool City”

An architecture oriented for a “Cool City”.
This project proposes facades and roofs that contributes to urban heat island reduction i.e. realization of a “Cool City”.

Potato foliage system
Potatoes are grown in between the outdoor units. The transpiration effect of leaves lowers the surrounding air temperature, reducing the intake temperature of outdoor units and contributing to increasing efficiency of air conditioning heat sources.
>So Suzuki
>Taro Hongo

Conceptual diagram of a potato foliage system

Cool Facade
Bio-skin Facade is a cooling facade system, which helps heat island reduction. When water evaporates from the surfaces of porous ceramic tubes, vaporization heat lowers the surface temperature to cool the surrounding air. A large reduction of surface temperature can be expected compared to no water flow inside the tubes.

Bio-skin facade (NBF Osaki Building)

Cool City - Urban Design

This project proposes district and city-scale measures for realizing the “Cool City”. The measures include not disposing heat to district for heat island reduction and designing total heat supply network in the district.

The feasibility of using canal water as the heat source was simulated.

Two-dimensional simulation of heat discharge to canal

Heat sharing, joining the energy and district
This project examines the grid connection between district heat suppliers and buildings with central heat source system to efficiently share heat among districts.

Image of heat sharing (in Nagoya City)

These ideas originated with "ID200", an activity where about our 200 engineers from the Building Services Design Division propose suggestions each year.

ID200

CATEGORY

RELATED EXPERTISE

Using Engineering Ability to Address the Environmental Problems of Urbanization

Use Wind, Air, Water, and Light to Design for Amenity in Public Spaces

Microclimate Design in Cool City

From Buildings to a “Cool City”

Cool City - Urban Design

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