Gnedash G. Energy-efficient combined heat recovery water-air heating systems for municipal boilers

The thesis is devoted to the researches directed at thermophysic justification of technologies of using of exhaust gases heat of municipal boilers with use of combined heat recovery systems. A complex of experimental and computational studies of heat characteristics for such systems with combined application of recycled heat for: a) heating the backward heating system water and blast air; b) heating and humidifying the blast air was implemented. The regularities of heat exchange in the hot-water surface heat-recovery units of combined heat-recovery systems for heating and humidifying the blast air under conditions of advanced moisture content in the flue gases, were determined оn the basis of experimental studies. For combined heat recovery systems, oriented for heating the backward heating system water and blast air, the peculiarities of influence of heat and design parameters of heat-recovery equipment on the heat characteristics were revealed. The exergic efficiency analysis and the optimization for proposed heat-recovery systems were done. By results of implemented research the concepts and technical solutions for combined heat recovery systems were developed. It is shown that the use of these systems provides increasing the utilization of fuel heat on 5 - 12% with a payback period of their implementation costs, not exceeding for the municipal power system boiler 3 years and for public sector - 0.7 years.