NOVELTY - Processing a biomass for using in a heating device, comprises supplying the biomass into a fuel dryer, drying the biomass by circulating processing air, and supplying the processing air moistened in the fuel dryer into an air dryer, where the processing air is first cooled in the air dryer via a heat exchange with a refrigerant , and the moisture is removed via condensation, and then the processing air is supplied into a first heat exchanger for heating, and is promoted through a blower between the fuel dryer and the air dryer.    USE - The apparatus or the device is useful for a heating device (claimed). The biomass is useful for a heating device.    ADVANTAGE - The method allows processing of the biomass in a simple manner and at low energy consumption.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) an apparatus for processing the biomass for its combustion by the above method, comprising a fuel- and an air dryer connected with each other via a process air circulation, where the air dryer exhibits a refrigerating machine for drying the processing air;    (2) a device for compressing the biomass in the form of pieces comprising a cylinder, whose inner operating chamber conducts a piston in an axially displaceable manner in an open-, closed- and an ejection position, two valves arranged laterally with respect to the cylinder, where the valves are conducted in a radially displaceable manner between the open- and the closed positions of the cylinder, two window openings formed in the cylinder wall, through which the valves in the operating chamber are pushed to receive the closed position, an ejection shaft for ejecting the compressed form of pieces, where the ejection shaft is designed at an end of the cylinder opposite to the piston, and a control, which controls the operation of the piston and the valves in their positions, where the piston and the valves respectively exhibit a deformation at the head side, and the deformation in the closed position of the piston and the valves forms a closed mold for designing a molded piece;    (3) compressing the biomass in the form of pieces by the above device, comprising filling the operating chamber with the biomass, moving the valves from the open position to the closed position, compacting the biomass in the operating chamber by moving the piston from the open position to the closed position, moving the valves from the closed- to the open position, ejecting the compacted form of pieces in the ejection shaft by moving the piston from the closed- to the ejection position, and moving the piston from the ejection- to the open position via the closed position; and    (4) operating the heating device with the above apparatus or the device, comprising crushing and drying the biomass, preferably domestic animal dung as a fuel in the fuel dryer using warmed processing air, then supplying the biomass via a conveying device to a boiler for combustion after the compression in a molded body, supplying the molded body at least partially to a temporary storage after the compression, and providing an exhaust gas heat of the boiler for heating the processing air.