Further development of "self-powered boilers"

The concept of "self-powered" appliances is one where a normally flame-heated appliance generates enough electricity also to operate its electrical components, and therefore the unit operates free from the electric grid. This would be in contrast to cogeneration, in which surplus electric power is generated to be used for other functions beyond the principal purpose of the appliance. Thermoelectric generating technology is very well suited for "self-powering". A series of "self-powered" residential-scale hydronic central heating units, often referred to as "boilers" although the circulating water does not boil, have been built with thermoelectric generating modules incorporated. These are modifications of compact, wall-mounted, highly efficient units that are a standard in the Netherlands and also popular in Great Britain and northern Germany. As well as adding the thermoelectrics, these modifications have involved conversion of the existing AC power consumers to DC wherever possible within the unit and in other ways reducing electric power demand. Each of the units built in the development phase has been more prototypic and more spartan in its electricity need. The present objective is a 22 kW/sub th/ (75,000 BTU/hr) heating unit that runs on 55 to 60 W/sub el/. Twenty of these units are being built and will be field tested in 1999-2000. It appears that the case can be made that the "self-powered boiler" is marketable now in economies such as the Netherlands, where the price gap between natural gas and electricity is wide, the prices of both are high and where comfort heating is utilized a large fraction of the year.