ENERGY EFFICIENCY OF BIOMASS GAS GENERATOR STOVES WITH PERIPHERICAL AND CENTRAL GASES BURNING

This paper is devoted to research and improvement of biomass gas generator stoves. Experience in outdoors application of the gas generator stoves showed a need to stabilize the burning of the generator gas. In previous works, investigations in operation of the gas generator stoves were carried out analogically to that of gas-fired household stoves in the mode of water heating in pot. Stoves operation in the mode of food cooking, which characterized byy other conditions of heat exchange, was not examined. The purpose of work is to investigate the influence of the organization of generator gas and air reaction with protection against atmospheric impacts on the energy efficiency of the gas generator stove in modes, which consistent with the stove usage for water heating for household needs and food boiling. To stabilize the gas generator stove operation, it was proposed to perform the mixing of generator gas with air and their reaction in the combustion chamber with the release of combustion products through the narrowed central opening. Comparison of two stove modifications was made — the first without combustion chamber, named as stove with peripheral burning, in which burning of combustible gas occurs near the air nozzles evenly spaced on the top of reactor; the second stove modification — with a combustion chamber, named as a stove with central burning, in which the combustible gas is more uniformly blended with the air, and burning occurs at center of the combustion chamber. Such an approach protects the combustion zone from atmospheric influences. The methodology of the research consisted in determining the energy efficiency coefficient of the gas generator stove with wood pellets burning at different approaches to the organization of generator gas and air mixing and reacting, as well as clarification of influence of stove application for water heating and water heating with prolonged boiling on stove’s energy efficiency. Experimentally find out, what stove with combustion chamber having central combustion and protection of flame from atmospheric influences in water heating mode had increased efficiency up to 29.6 % compared to 25.1 % for the stove with peripheral burning. The average useful heat productivity of stoves both with the peripheral and central combustion was near the same 1.2 kW. Application of gas generator stove for water heating with its prolonged boiling (cooking mode) led to a decrease in efficiency, for the stove with central burning efficiency decreased from 29.6 % to 21.9 %. Ref. 9, Fig. 1, Tab. 3.