Development of a coal fired pulse combustor for residential space heating. Technical progress report, July--September 1987

The systematic development of the residential combustion system is divided into three phases. Only Phase I is detailed here. Phase I constitutes the design, fabrication, testing, and evaluation of a pulse combustor sized for residential space heating. Phase II is an optional phase to develop an integrated system including a heat exchanger. Phase III is projected as a field test of the integrated coal-fired residential space heater. The Phase I effort was nearing completion during this reporting period and a final report is in preparation. The configuration testing was completed early in the period and based upon results of the configuration tests, an optimized configuration for the experimental development testing was chosen. The refractory-lined chambers were fabricated and tested from mid-September through early October. The tandem unit was operated on dry micromized coal without support gas or excitation air for periods lasting from one to three hours. Performance was stable and turndown ratios of 3:1 were achieved during the first three-hour test. A early commercial residential heating system configuration has been identified on the basis of the development testing conducted throughout the first phase of this effort. The development effort indicates that the residential unit goals are achievable with some additional product improvement effort to increase carbon burn-out efficiency, reduce CO emissions and develop a reliable and compact dry, ultrafine coal feed system (not included in the present effort)