Rex Lehmann: Saving air conditioning power costs. Large airport terminal roofs present a huge solar-heat-absorbing surface in the warmer climates, resulting in the air conditioning being the largest demand for electricity within the terminal.
A metal roof - galvanised or painted - will typically absorb the bulk of the sun's heat, such that on a 30°C day, the outer roof surface will typically reach more than 60ºC. We have actually measured roofs at 87ºC.
Much of that heat will be radiated to the interior of the building. Roofing insulation can only slow the ingress of the heat - it can never prevent it. Once the interior has been heated, the insulation traps it in.
No. Normal white metal roofing will reach temperatures nearly as high as galvanised surfaces.
Client feedback has been enthusiastic, with many pointing out other benefits beyond direct power saving. Melbourne Airport, for instance, advised us that the SkyCool restoration and coating of a 40-year-old roof saved capital works in excess of $1.5 million. The same concourse was able to shut down 16 auxiliary air-con units made redundant by SkyCool.
After the completion of the 47,000m2 of SkyCool coating at Melbourne Airport, they announced on national television and at ACI the high degree of energy savings they obtained from this cool-roof coating (CRC).
Quite a number of the clients, including Perth International Airport and Darwin International Airport, have also commented on the outstanding results from their installations.
The science behind CRC is quite complex, so I'll just highlight the two vital elements.
The first is that a CRC must exhibit a very high reflectance of visible light and near-infrared radiation. And it must maintain that level of reflectance throughout its life. Almost all CRCs fail in this factor, many (not SkyCool) lose as much as a 30% reflectance within the first two or three years of installation, resulting in little energy savings over the longer term.
The second factor, often missed in CRCs, is its thermal-radiation capabilities. SkyCool, for instance, has a highly tuned radiation capability such that it will emit around 96% of any absorbed heat into space. This radiation helps cool the building's interior 24 hours a day, even when the air conditioning is not running.
Professor Geoff Smith of the University of Technology, Sydney, who was the 2011 scientist of the year, has been an adviser to SkyCool from the beginning and maintains a scientific advisory role at SkyCool.
Queensland University of Technology Professor John Bell made the following observations about the technology, "The benefits of this type of cooling on building energy use, and internal comfort, which results from reduced air conditioning and lower roof temperatures, can be substantial. Under these circumstances, significant savings in operating energy costs, and also potential reductions in plant size and peak energy demand, are added benefits."
Another key benefit of SkyCool is that it is an 'install and forget' coating with no maintenance required. It has been tested to world standard UV resistance and found that there is no degradation after 25 years of tropical-strength exposure.
SkyCool is installed on data centres in the banking, university, security and government sectors. And warehouses, shopping malls and supply chain facilities continue to be well represented among the users of this technology. In summary, at Skycool we believe that the cheapest energy is the energy you no longer have to use to achieve the same outcome.