• Categories

  • Most Popular Questions

  • Recently Viewed Questions

  • Recent Answers

    How To Make a Digita… on What does a frequency of 100 H…
    Daigrepont on Can an earthquake cause air tu…
    Benedict on How did God come into exi…
    joshua on How does the human body g…
    Ian on How did God come into exi…
  • Recent Questions

  • Blog Stats

    • 2,214,946 hits
  • Visitors since 11-3-08

    counter create hit
  • Terms and Conditions

  • Warning

    We are doing maintenance on this site, so some posts may disappear for a short time. Sorry. Normal service will soon be resumed...
  • Pages

  • March 2008
    M T W T F S S
    « Feb   Apr »
     12
    3456789
    10111213141516
    17181920212223
    24252627282930
    31  
  • Archives

  • Meta

As energy can neither be created nor destroyed, why can’t we conserve energy by converting low grade heat directly into electricity?

As energy can neither be created nor destroyed, isn’t there is a real opportunity to conserve energy and make efficient use of power by converting low grade heat directly into electricity. This concept has wide applications from data centres to factories and ultimately even in the home with domestic appliances, assuming the processes involved could be made efficient enough to be economic on such a small scale. Is there any research being carried out into the development of this concept?
John Woolley from Oxfordshire (Age 55+)

Advertisements

One Response

  1. There is, in two instances that I am aware of. On a domestic scale, Combined Heat and Power systems are used – as the name suggests – to generate heat and electricity from the same source. The hot water or air in a boiler drives turbines when it is circulated to the rest of the heating system, generating power. A CHP system can be 70% efficient in its production of useful heat and electricity, comapred to about 40% for standard powerstation. CHP systems can also be scaled down for use in normal family homes or in larger factories.

    There are other techs which reclaim heat, rather than making more use of it in the first place. When a conductor has different temperatures at each end, a voltage is generated across it as the electrons in the hot end gain more energy and spread out, pushing the others along. To use this voltage, a second conductor has to be connected, which will generate its own voltage in the opposite direction. If these are the same type of conductor, the effect cancels out, but since the voltage generated for a given temperature depends on the material, you can combine different conductors to create a device that gives out voltage when exposed to temperature differences. These are called thermocouples, and are commonly used as measuring devices, but they can be used to generate power. The pilot light on most boilers is powered thermoelectrically. Also, the Cassini and Huygens probes use thermocouples to convert the heat generates by the radioisotopes inside them to power for their interplanetary journeys. But thermocouples aren’t commonly used as power sources on Earth because they have a low efficiency when the temperature difference is small. People are working on this though: check out this page at Caltech if you’re interested. http://www.thermoelectrics.caltech.edu/

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: