Abstract:Several issues existing in the biomass stoves, such as low thermal efficiency, substandard fire intensity, insufficient air supply, uncomplete combustion, substandard emission and unitary function. According to the requirement about the environmental cooking stoves with biomass pellet fuel for centralized food catering, a novel direct-fired cooking stove with biomass pellet fuel was designed to solve the mentioned shortcomings. An annular evaporator was installed above the furnace, the water inside the evaporator was heated by the peripheral flame and flue gas, and high temperature steam produced from evaporator was assigned to different routes to achieve the direct-fired cooking stove combined functions of stir-fry, steamed rice, boil water and thermaling. Meanwhile, in order to ensure the uniformity of air intake,a grid shaped air inlet sleeve was designed, the wind was blown into the furnace in a rotating form. Moreover, all the integrated functions can run simultaneously. According to the national standard NB/T 34015—2013, the direct-fired stove was tested. The performance test results of the redesigned cooking stove showed that the thermal efficiency for cooking reached 42.9%, and the integrated thermal efficiency was 70.7% combined with the thermal used for heating water. The fire intensity for cooking was 14.1kW, and emission indexes of flue gas was lower than the national standard. The novel design of the cooking stoves with biomass pellet fuel realized the complete combustion of biomass particles, which can provide reference for the design and application of direct-fired pellet stove.