Reducing Urban Heat

When was the last time you cycled away from the town after dark? As you left the buildings in the area behind did you notice just how the temperature range lowered? Particularly detectable at night, when there's little or no breeze, you immediately observe the particular way our created surroundings builds as well as stores warmth that is then released.

This is known as the Urban Heat Island Effect.

An urban heat island is created when the concrete and bricks of houses in the area and the asphalt of streets have replaced the permeable vegetation layers of the natural landscape.

The actual talent of a town to accumulate and collect heat in this fashion was first identified by a British meteorologist, Luke Howard, in the early 1800's. Since the 1800, buildings have become bigger and towns have spread out claiming more green land. As well as structures multiplying in amounts and scale, we've introduced more technology, from cars to air-conditioning, which in turn pushes a lot of heat into the places where people are living.

Satellite know-how today allows us to measure a lot more properly temperatures of our urban and rural regions. The results show that we've established 'islands' throughout our natural landscape, which you'll find warmer as opposed to the surrounding natural landscape. The demand for higher cooling because of the increase in temperature results in additional energy usage and even more air pollution. Additional pollution and higher temperature ranges help to make cities less pleasant locations to reside in and may also affect the overall healthiness of people that reside and work there.

Stormwater can damage fragile ecosystems if it is warmed up as it runs off of the non-porous surfaces of buildings and pavements and then released into streams. Often the rainfall itself can cause concerns so that designers and urban planners have to produce complicated systems to channel it faraway from population centres. Rainwater can sometimes fuse with sewage and result in increased health conditions and damage to ecosystems.

Approximately 50 % the world's population lives in towns and cities and also the numbers are increasing year after year. Mainly because we can't alter exactly where people today are living, urban advisors search for means of creating the usable liveable space far healthier and increasing energy-efficient.

Roofs makes up a large proportion of almost any city's surface area. They signify a major factor in the heat island problem but maybe since they're generally out of sight, they are usually disregarded. Every object has an ‘albedo' - the speed at which it can reflect radiation from the sun's rays. Areas in a city which may have a lower albedo are usually not as effective as they do not reflect radiation away from the surface and thus assist in keeping structures warmer.

Reflecting no more than 26% of the sun's radiation, classic asphalt built-up rooftops have a very small albedo. All of the other solar radiation is absorbed and creates heat that stays in the area when there is no wind.

An eco-friendly roof however, possessing a raised albedo, reflects a lot of the sun's radiation out of the property. It additionally supplies cover from the sun and heat insulation which will keep the structure underneath it cooler. The vegetative layer keeps rainwater, as an alternative to merely heating it and moving it away. The evaporation of water from the substrate and transpiration of humidity from the plants and flowers acts to cool the rooftop and prevent it from turning into yet another source of urban heat.

Flat roofing systems which are cooler can play a crucial role in offsetting the negative effect of the urban heat island.