Previous in Forum: Effect of belt driven pulley on motor   Next in Forum: About the alternator
Close
Close
Close
14 comments
Rate Comments: Nested
Member

Join Date: Jul 2007
Posts: 8

Heat Energy to Electrical energy

08/01/2007 6:16 AM

Dear Friends,

Is there any device to convert heat energy to electrical energy directly,without any intermediate conversion.(Similar to Photovoltaic cells which convert light energy to elctrical energy directly).

If yes what is the device?

Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Guru

Join Date: Jul 2007
Location: Commissariat de Police, Nouvions, occupied France, 1942.
Posts: 2599
Good Answers: 77
#1

Re: Heat Energy to Electrical energy

08/01/2007 6:37 AM

Something that will produce rotation, followed by a generator. A working fluid is usually involved, as are the Laws of Thermodynamics. Let's see:

  • Thermal power station?
  • Stirling engine + generator?
  • Gas turbine +generator?
  • Cyclist with a dynamo on his bike?

Without an intermediate conversion. What does this mean? Ah! Let's try: no fluid.

  • a photovoltaic cell that will work with infra-red?
  • a thermocouple?

Wow! This is a broad subject!

__________________
Good moaning!
Register to Reply
Power-User
United States - Member - New Member Fans of Old Computers - PDP 11 - New Member Hobbies - HAM Radio - New Member

Join Date: Jan 2005
Posts: 381
Good Answers: 8
#2

Re: Heat Energy to Electrical energy

08/01/2007 9:21 AM

Thermoelectric devices convert heat energy directly to electrical energy using the Peltier-Seebeck effect. Such devices (the thermocouple mentioned above by Crabtree is one example, though there are others) need a hot side and a cold side in order to operate. The power generated is related to the temperature difference between the hot and cold sides. Efficiency of these devices tends to be very low (less than 10%). Since the effect is reversible (applying a voltage difference will cause one side of the device to get cold and the other side to get hot) they are most often used as coolers, where they have the advantage of being very small, having no-moving-parts, and being silent. There are a few consumer products that use thermoelectric coolers (TECs) - such as camping coolers and office desktop coolers.

The major manufacturers of general purpose TECs in the US are probably Marlow and Melcor, although you can find other manufacturers here on GlobalSpec. Many manufacturers specialize in TECs for the optical industry, where sensors must be kept cool. Since, as I said, the effect is reversible, these devices can also be used as generators.

Register to Reply
Member

Join Date: Jul 2007
Posts: 8
#3
In reply to #2

Re: Heat Energy to Electrical energy

08/01/2007 11:08 PM

Thanks for the Reply.

Worth Information.

Register to Reply
Guru
Belgium - Member - New Member APIX Pilot Plant Design Project - Member - New Member

Join Date: Aug 2006
Location: Glabbeek, Belgium
Posts: 1480
Good Answers: 28
#5
In reply to #3

Re: Heat Energy to Electrical energy

08/02/2007 3:01 AM

We discussed this before and indeed there are some processes known that do this:

- Peltier-Seebeck elements as described before. They need a direct delta T.

- Thermocouples (TC): don't need a direct dT but only deliver small voltages but high currents, to be able to push the voltage up the are put in series, for this you need a dT. There is quite a dicussion on the dT effect of thermocouples: some try to explain the dT in the difference between where you have your TC and your measurement device. Typical TC's have a zero passage in the temperature spectrum of our normal living conditions (between 0°C and 25°C) and are useless to cool to this level.

TC's are used in radioactive decay electric batteries: the decay heats up a source and the heat is converted through a series of TC's interior of the device and outside. The USSR used them in space and remote power supply. Russia tended to remove them and recover the decay products but that did not really work out.

A third system is to use the long wave radiation of a flame/hot surface and convert it directly to energy is special PV cells. Normal PV cells need UV or blue light (short wavelengts, high energy photons) but some variants can work with wavelengths from the high IR zone. efficacy goes up to 25%, which is pretty OK for a simple system without moving parts.

It all depends on the temperature levels you have and the dT you can offer.

__________________
"Here we are now, entertain us"
Register to Reply
Associate

Join Date: Jan 2007
Posts: 46
#4

Re: Heat Energy to Electrical energy

08/02/2007 12:23 AM

I think what you need is athermocouple made of semiconductor material then heat up the hot junction and cool down the cold junction and get electric energy.

Register to Reply
Anonymous Poster
#6

Re: Heat Energy to Electrical energy

08/02/2007 8:34 AM

When my wife gets hot it can get pretty electric.

Register to Reply
Guru
Belgium - Member - New Member APIX Pilot Plant Design Project - Member - New Member

Join Date: Aug 2006
Location: Glabbeek, Belgium
Posts: 1480
Good Answers: 28
#7
In reply to #6

Re: Heat Energy to Electrical energy

08/02/2007 9:01 AM

You're correct: when your wife get's hot ..

__________________
"Here we are now, entertain us"
Register to Reply
Power-User

Join Date: Dec 2006
Location: Bolingbrook Illinois, a southwest suburb of Chicago.
Posts: 367
Good Answers: 3
#8
In reply to #7

Re: Heat Energy to Electrical energy

08/02/2007 9:12 AM

he asked us not to tell..

__________________
"People find it easier to forgive you for being wrong than for being right" J K Rawlings
Register to Reply
Guru
Belgium - Member - New Member APIX Pilot Plant Design Project - Member - New Member

Join Date: Aug 2006
Location: Glabbeek, Belgium
Posts: 1480
Good Answers: 28
#9
In reply to #8

Re: Heat Energy to Electrical energy

08/02/2007 9:23 AM

She asked me other things

__________________
"Here we are now, entertain us"
Register to Reply
Power-User

Join Date: Oct 2006
Location: Indonesia
Posts: 102
#10

Re: Heat Energy to Electrical energy

08/02/2007 9:57 PM

mvel sky,

I have ever heard this question before then brought me to TPV (ThermoPhotoVoltaics). Some observers in some well-known-universities have been trying to develop another alternative energy source. Just use the TPV or ThermoPhotoVoltaics to start searching (e.g by google).

Register to Reply
Active Contributor

Join Date: Nov 2006
Posts: 19
#11

Re: Heat Energy to Electrical energy

08/03/2007 5:53 PM

"You Tube" shows a revolucionary motor running only under permanent magnetics. It is not possible identify which country this motor is made. If this device realy comes true i thing we are as yet in a new age about electric power generation. Please, i ask for all CR4 members to tell me anything about this kind of "future"motor. Where can I see this motor working as a matter of fact ? Fernando: acquaway@acquaway.ind.br

Register to Reply
Power-User
United States - Member - New Member Fans of Old Computers - PDP 11 - New Member Hobbies - HAM Radio - New Member

Join Date: Jan 2005
Posts: 381
Good Answers: 8
#12
In reply to #11

Re: Heat Energy to Electrical energy

08/03/2007 7:22 PM

If it runs on "only permanent magnets, then its a perpetual motion machine - and its crap. It won't work, period. I've seen MANY of these over the years (I used to manage the motors and drives group at GE Corporate Research and Development). The law of conservation of energy stands undimmed - they don't work.

Register to Reply
Active Contributor

Join Date: Nov 2006
Posts: 19
#13
In reply to #12

Re: Heat Energy to Electrical energy

08/06/2007 5:24 PM

Thanks very much for your reply! All people must agree with base science laws. Sure, my comment about "only permanents magnets motor" sounds like a non sense matter. Ok! Realy, it´s not possible a perpetual motion machine! However, the video in WEB ( You Tube ) shows this motor device and a motorcycle well running in Japan ( ??? ) perhaps in Austria ( ??? ). In the other hand, i don´t think this motor could be similar to Perendev Magnets Motor. I can send this video to you as an e-mail file attached, if you want so. Then, we will be able to talk about science and real machines! Just because the law of conservation of energy i am asking any one CR4 member: Please, tell me where can i can keep watch this kind of "motor", working three months at least, in a continuos way? Sure, assuming it is a true machine and so, with mechanical and electrical engeneering specifications.

Register to Reply
Power-User
United States - Member - New Member Fans of Old Computers - PDP 11 - New Member Hobbies - HAM Radio - New Member

Join Date: Jan 2005
Posts: 381
Good Answers: 8
#14
In reply to #13

Re: Heat Energy to Electrical energy

09/11/2007 1:45 PM

"Please, tell me where can i can keep watch this kind of "motor", working three months at least, in a continuos way?"

You can't. A machine that can do this doesn't exist. The "Perendev Magnets Motor" has never been satisfactorily demonstrated, and will never be, because it can't work!

The law of conservation of energy is time-tested. When someone shows you a new device you first step should be to see where all the energy flows are. If energy is coming out without any energy flowing into, or stored in, the device, then it will not work.

Register to Reply
Register to Reply 14 comments
Copy to Clipboard

Users who posted comments:

Abu Khansa (1); ACQUAWAY (2); Anonymous Poster (1); Crabtree (1); Gwen.Stouthuysen (3); jfbenam (1); mvel_sky (1); NoSciFi (1); Steve (3)

Previous in Forum: Effect of belt driven pulley on motor   Next in Forum: About the alternator

Advertisement