Re: Is there a way to convert heat to electricity?

The answer is yes.  The device is called a "thermoelectric module."  It uses 
something called the "Peltier effect."  See this website:
 http://www.aoc-
cooler.com/PELTIER-EFFECT.htm

Now the Peltier effect takes electric current and makes a temperature 
difference.  What you want is a temperature difference to make an electric 
current.   Guess what:  The thermoelectric module works both ways.  When the 
temperature difference makes a current, the new name for the phenomenon is 
called the "Seebeck effect."  The thermoelectric module uses doped 
semiconductors to perform its energy transformation.

Both effects were discovered before semiconductors became common.  At the small 
temperature differences available for everyday use, semiconductors do it better 
than thermocouples, on which these effects were discovered.    A thermocouple 
is an electrical connection of two dissimilar metals.  Heat the junction, it 
produces a voltage difference.  Pass a current through it, it creates a 
temperature difference.

Use of metallic thermocouples to produce electricity for power is not common, 
although it is for temperature measurement.  But you do it where you have no 
choice.  Space missions far from the sun use a "thermopile"  -- series-
connected thermocouples, half exposed to the near absolute zero of space, and 
half exposed to radioactively-decaying (hot!) plutonium.  This great 
temperature difference generates considerable, long-lasting power (can't use 
batteries or solar cells) on 20-year missions, and is what powered the 
apparatus that gave us all those magnificent images from the Voyager missions.

Thermoelectricity is a study all in itself.  I hope I've given you a start in 
learning about it.

Larry Skarin