As far as I know, thermopiles are not sold as a separate unit. All of the thermopiles I encountered were installed by the manufacturers of various water heaters and heating units as standard equipment. They were all intended for indoor use. What you are calling a thermocouple may very well be a thermopile.
They were very widely used back in the 1950s and 1960s in wall furnaces, and the now illegal floor furnaces., they are still used in most water heaters. Since the voltage is measured in milli-volts, it is far less than one volt. We used to run a wire to a wall mounted thermostat for floor furnaces. It used to drive the electricians nuts, since no electrical license was required to work on voltage that low.
They all seemed to be a single unit device. The main advantage to them is that no external power is required for them to work. Today, there is probably not one uneducated plumber in 100 that has even heard of a thermopile, even though they may have installed hundreds of units with them pre-installed.
Many sheet metal workers installed those units too, since it depended on which sub-contractor had the contract to provide the heating in a project to determine who would install the heating units.
Rex "The supreme happiness of life is the conviction that we are loved" - Victor Hugo
(This post was edited by Papirex on Feb 10, 2012, 10:05 AM)
Post edited by Papirex
(Veteran) on Feb 10, 2012, 10:05 AM