April 16, 2013

...AND CHEAPER...:

Smart heat nets fire the next energy revolution (Chelsea Wald, 4/15/13, New Scientist)

The good news is that several cities have found a way to hunt down their waste heat in some unexpected places. These cities are building systems that deliver heat in much the same way that networks handle electricity and water. Could they point the way to the next energy revolution?

Waste heat is an enormous problem. A report in 2008 by the US Department of Energy found that the energy lost as heat each year by US industry is equal to the annual energy use of 5 million Americans. Power generation is a major culprit; the heat lost from that sector alone dwarfs the total energy use of Japan. The situation in other industrialised countries isn't much better.

The report also estimated that given the right technologies, we could reclaim nearly half of that energy, but that's easier said than done. "We often talk about the quantity of waste heat," says David MacKay, chief scientific adviser to the UK Department of Energy and Climate Change, "but not the quality." Most of what we think of as "waste heat" isn't actually all that hot; about 60 per cent is below 230 °C While that may sound pretty hot, it is too cold to turn a turbine to generate electricity.

The alternative is to just move the heat directly to where it is needed. That is what "cogeneration plants" do. These are power plants that capture some or all of their waste heat and send it - as steam or hot water - through a network of pipes to nearby cities. There, buildings tap into the network to warm their water supplies or air for central heating.

Posted by at April 16, 2013 7:41 PM
  

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