Discussing the evolution of self-powered appliances, David Brown-ell of Yankee Scientific, Inc. (Medfield, MA) talked about heaters that produce their own power, generators that also produce heat, and battery-powered appliances.
Self-powered systems are attractive because deregulation has made the grid less reliable while dependence on electricity has been increasing, said Brownell.
Developments in process include low-pressure steam-powered room heaters that require no electric power and a low-pressure steam air handler that connects to a standard steam boiler. Small thermoelectric generators (TEG) have led to a TEG-powered, pressurized hot water heater.
A liquid-injected cogeneration warm air furnace and a battery backup system for boilers are also on the horizon.
New technology, he said, will bring mid- to high-power applications to market.
Richard Oman of Insight Technologies, Inc. (Bohemia, NY) talked about creating a practical oil-fired heating system with reduced electric power consumption and battery backup.
The 12-vdc permanent magnet motor doubles efficiency, while the fan is an improved design. The prototype burner developed cuts electrical power tenfold, Oman stated. Using 12- vdc components allows standalone operation with survival heating levels of about 24 hrs.
Brownell also provided a presentation on the development of liquid-injected cogeneration for the home. Micro-cogeneration provides residential-scale heat and power. Power is extracted from combustion products before heat is supplied for end use. The system uses a mono-tube instantaneous liquid heater with 3 oz. of totally contained hot water.
Such a system, he asserted, will be able to provide 100% of the required heat in a home, and nearly eliminate the homeowner’s electric bill in wintertime. It produces electric power with less than half the fuel and CO2 emissions of central power plants.
Finally, Thomas Butcher of Brookhaven National Laboratory (Upton, NY) spoke on thermophotovoltaics. When you generate electric power in this way, you have to control the light spectrum that hits the photovoltaic cells. Light goes from the emitter to a filter, with a narrow band going to the cells.
A lot of work is being put into optimizing the filter, Butcher said. In testing to date, the system is producing a few watts per square centimeter. Researchers expect to greatly increase that. Improvements being developed include a 4 to 1 concentrating prism.
Publication date: 03/26/2001