High-efficiency gas furnace modification in low-income housing

Abstract

Heat Extractors (a direct-contact type of secondary condensing heat exchanger) were installed on the conventional gas hot-air furnaces in 100 ''scattered site'' rental housing units owned by the Philadelphia Housing Authority. The Heat Extractor is designed to draw off the flue gases which normally would go up the chimney, and condense them on a water spray; the latent heat thus reclaimed is used to raise the temperature of the return air, and the cooled flue gases are vented horizontally. The installed cost was $695 per unit. With funds provided by an Energy Task Force grant, the Energy Unit in the city's Office of Housing analyzed the energy savings achieved in these installations; it evaluated the applicability and cost-effectiveness of the Heat Extractor technology. On the basis of published laboratory studies, project planners expected that gas use for space heating would be reduced by 15 to 30 percent. This would correspond to a total gas savings in the 12- to 24-percent range. The project had three related purposes. The first was to develop a series of routine procedures for analyzing residential energy consumption accurately. The second purpose of the project was to verify the effectiveness of the Heat Extractor, which, if more » it performed as claimed, could be a treatment of choice in several low-income energy conservation programs. Again assuming that the technology proved cost-effective, the third purpose was to develop suitable plans and guidelines for its use by the city's public housing authority and housing development agency. 12 refs., 6 figs., 4 tabs. « less