Comments on: Smokestack heat: Fuel of the future?

Escaped heat is an underused resource for electricity and heating. New technology and a push toward energy efficiency could make recycled energy more attractive.

[alstatr]

why is all this green tech always 10 years away?

[mlamonica]

Waste-heat recovery is already done - note the information on existing companies and the graphic. That's all today. Using thermoelectrics for waste heat recovery is farther out.

[david_hume]

If you take heat from a smokestack, the plume temperature reduces, and thus buoyancy is reduced too. This causes emitted pollutants to reach ground at shorter distances, with higher concentration values. This can be worse to the environment than some heat recovered.

[mlamonica]

in reply to david_hume. That assumes there are no air quality controls, like scrubbers, in place to reduce particulates, etc.

[d.gallea]

Reality check:

Article said: "Clary said appliance maker Bosch has shown interest in making a home-heating unit with an attachment that makes electricity from exhaust heat. At 10 percent efficiency, a home could meet its power needs with the heat on."

OK, let's posit a 200 kBTU/h (typical) thermionic (hot water) boiler rinning at 85% (typical) efficiency. During an "on" heat cycle, 30 kBTU/h (200k x 15%)go up the stack as waste heat. If we recover 10% of that, per the target efficiency of the subject device, it would be 3000 BTU/h. That's 880 watts. A typical home using about 500 kWh/month draws, on average, about 700 watts. So the claim seems to be proven, if only during an "on" heat cycle. I suspect that, averaged through a year, only about 15-20% of a household's electrical needs would be covered by waste heat conversion. It's still significant, however.

[yacahuma]

Is related to how long Bush has been president

[Electro_Fox]

Wow... Irrelevance. How refreshing, troll...

[Foggy]

Does this mean that solar panels could be made of a substance that not only converst the rays of the sun into electricity, but also also converts the absorbed heat into electricity. Likewise the asphalt shingles on a roof absorb a lot of heat and the heat in an attic is wasted during the summer months, the same for an asphalt driveway or parking lot particularly in the southern states could be converted into heat sponges.

[mlamonica]

Not sure on your first question but there are already solar electric panels that use excess heat to make hot water.

As for using hot asphalt for energy, there are people working on that: http://news.cnet.com/8301-11128_3-10019386-54.html?tag=bl

[DigitalFrog]

Not really a new idea, although one that needs to be used more widely. I know of a natural gas-chemical processing plant that pumps it's waste heat next door into a greenhouse operation. A nice touch is that you don't lose more energy as it is already in the form of what was needed - heat.

The opening paragraph though is useless: "rather than install solar panels on your roof, the lost heat from your furnace could power your home. " The newer furnaces these days have almost no waste heat. If you have enough waste heat from your furnace to generate any appreciable power, upgrading to a high efficiency furnace would save you more on your energy bills and be greener.

[k2dave]

It would not be 'greener' - exactly what that term really means is anyone's guess. If you produce electricity and use all the waste heat in the process that is 100% efficient and you are producing a high quality form of energy (electricity). This is much better then producing heat at 100% efficiency and buying electricity from a coal power plant that is 50% efficient.

[speakforthose]

Thanks for this piece. I'm associated with Recycled Energy Development, the company you mention near the bottom of the piece as the "granddaddy" of waste heat recovery. Studies done for DoE and the EPA suggest we could slash greenhouse emissions by 20% if we did more energy recycling in this country. At the same time, we'd cut costs by about $70 billion. And all this can happen NOW -- these technologies aren't years away. They're here.

So why isn't more being done? Simple: regulations protecting monopoly utilities make it really hard for competition to take root and for more efficient alternatives to emerge.

[cambeyk]

http://www.allercheap.com

[chamm3r]

Now all we need to do is capture the heat generated by our laptops to recharge the battery. As hot as my laptop gets, that ought to be an infinite power source!

[OrionCA]

Regenerative heat recovery is nothing new. However, there's a theoretical limit to the amount of work you can extract from a heat source and most power plants - even those in the US - work at the limit of what's reasonable and economical. You can pump water across a smokestack to make steam, for example, but it costs money to run the pump and maintain the heat exchange system. It's a nice gimmick for the touri groups but chances are a high-efficiency gas boiler would be just as cheap if not cheaper.

[Video Edit]

In 1932 there was a Russian radio that was worked by 'Flu' gas and had a block of thermo junctions (type un-known) in a section of flue pipe a seemed to power the HT of a radio (it still needed a lead acid Lt battery) that was supposed to be for the masses but I have only come across the one reference to it, in an old wireless world 60's that has been 'filed away' ...
Things do go in cycles

[Video Edit]

In 1932 there was a Russian radio that was worked by 'Flu' gas and had a block of thermo junctions (type un-known) in a section of flue pipe a seemed to power the HT of a radio (it still needed a lead acid Lt battery) that was supposed to be for the masses but I have only come across the one reference to it, in an old wireless world 60's that has been 'filed away' ...
Things do go in cycles

[DigitalFrog]

What we really need is a system to generate energy from all the hot air being produced at the Democractic Convention. That could power the country for a year!!

[NicoleEverson]

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