portable or temporary heating is provided by locating a container adjacent an area to be heated in which the container comprises a portable building including a coal storage compartment and a heating compartment therein . a heating apparatus , for example a boiler , is provided in the heating compartment which consumes coal . the coal storage compartment includes a transfer mechanism for transferring the coal stored therein to the heating apparatus responsive to fuel demands of the apparatus . ambient heat from the heating apparatus is used to maintain coal in the coat storage compartment above freezing to prevent bridging thereof .