Heating pellet

A heating pellet comprising:

• a circular bottom area comprising a circular central area, an outer ring and a concentric annular transitional ring between said central area and said outer ring;
• a concentric sidewall extending outwardly and upwardly from said outer ring;
• a concentric rim extending upwardly from said sidewall;
• said concentric rim being of sufficient vertical dimension so as to permit an upper similarly dimensioned heating pellet to nest and stack over a similarly dimensioned lower heating pellet so that the top of the concentric rim of the lower pellet is in contact with and nestingly supports the upper pellet only at a substantially annular contact area on the underside of the concentric sidewall of the upper pellet near its concentric rim whereby said upper pellet is nested within said lower pellet with a space between the upper and lower pellets inwardly from said annular contact area;
• said rim having at least one notch permitting the passage of air from outside said rim into the space between said upper and lower pellets when a plurality of similarly dimensioned pellets are in a nested and stacked relationship;
• and
• an access hole through said circular central area of sufficient transverse dimension so as to permit the passage of air through adjacent access holes of a plurality of similarly dimensioned pellets in a nested and stacked relationship,
• whereby a plurality of similarly dimensioned nested and stacked pellets may be heated or chilled by convection by circulating warmed or chilled air over and through the space between nested and stacked pellets through said notch and access hole.