A fixing device comprises a rotatable fixing member to apply heat to a recording medium bearing an unfixed image thereon, a heat source to heat the fixing member, and a rotatable pressing member pressing against the fixing member forming a nip therebetween. The dispensing device is partly submerged in the water, with its upper part projecting out of the water, with the food being deposited on the shelf in the upper part and, by means of impulsion of water using a pump, said food will be moved from one shelf to the next, alternately, towards an outlet in the zone underneath the lower shelf. The polymer gel releases thermal energy to the cooling chamber as the chamber is cooled to attain essentially the same temperature as the cooling chamber and absorbs thermal energy from the cooling chamber when the heat transfer module is deenergized and the cooling chamber begins to warm. The convex-shaped feature is stepped-shaped, stair-shaped, or ladder-shaped.