The Thermal Effects of City Living 3

Monday, July 27th, 2015
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Heat absorbing building materials, glass panel skyscrapers and glass reflective facades have damaged property and can seriously affect the quality of life for city residents. This poses a serious challenge for engineers and other building professionals in our major cities’ high-rise future.

Some 30 years ago, Tandy Electronics sold a curious convex polished steel dish with a centrally located stand for holding a cigarette.  One pointed the dish toward the sun and presto! Within a few seconds, the cigarette was alight and smoking away. Fascinating as it may be, such is the power of the sun when its rays are focused on a particular point.

In a similar way, glass panel skyscrapers and reflective facades have potentially undesirable consequences for surrounding buildings and amenities. In London, there has been a reported incident of a Jaguar motor vehicle ‘melting’ due to reflective heat from a glass panel building. It has been noted in some cities that the temperature can be five degrees Celsius greater in hig- rise areas than in surrounding low-rise suburban areas.

The federal government’s 2013 State of Australian Cities report identified that people living in high-rise cities are more susceptible to heat waves stress than those in low rise suburbs.

On the one hand, heat absorbing materials such as dark coloured roofs and buildings absorb heat, whilst at the same time reflective heat from buildings can also raise the temperature.

The answers to this include building structures using low heat materials and colours, ensuring facades will have minimal reflective impact on surrounding areas, and planning for greater shade and green space.

Of the nation’s capital cities, Melbourne has the highest annual number of heat-related deaths. In 2013, the figure was around 200, which is significant when it is compared to the road toll of 213 in the same year.

In building for the future, we need to plan and engineer outcomes to relieve the significant and apparently ever increasing adverse effects of dense high rise city buildings.

Heat-related deaths are predicted to increase by 100 per cent by 2030, and the frightening reality is that 2030 is only 15 years away.

One noted expert has suggested that “we need to have green roof gardens, green walls and use materials that reflect the heat.”

However, we must also ensure that the reflected heat is reflected away from neighbors and surrounding amenities such streets and roads, as otherwise it is not solving the problem but adding to the existing heat, albeit in another local area.

The challenge is there and thermal engineering in buildings will play a significant role in the construction of ever increasing high rise cities. The utilisation of the sun’s rays and the evolution of high-rise cooling systems are challenges faced by engineers in the construction of our cities of the future.

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  1. Stephen L.

    The problem with green cover in cities is that it makes them look abandoned and unkempt.

  2. Roger Jones, P.Eng, SMIEEE

    I understand that one of the problems is accidental (or design!) concave mirror shapes of some glass facades focusing heat onto sidewalks and other buildings at certain times of the day.

  3. Balajee .K.Vaidhyanathan

    It's predictably alarming,that "Heat Absorbing" buildings & Roof-tops….are potential Heat Radiators & Reflect Heat thus absorbed. Sustained Heat ,will emit at regular intervals…on every day basis. Glazings & Glass panels are no doubt ,attractive but carries high risk for the living beings. Thermal engineering & alternative building materials….like in the case of Sand now " M-Sand " (manufactured Sand )is the prerogative & should be identifies for testing & implementing.Sooner the better.