NOVELTY - The operating method involves transferring heat produced by a fuel cell module (202) towards a thermal energy storage module (218) including a phase-change material, storing the heat produced by the fuel cell module in the thermal energy storage module, and channeling water produced by the fuel cell module through the thermal energy storage module to facilitate controlling a temperature of the thermal energy storage module. The water produced by the fuel cell module is channeled through a conduit (216) using a water pump (210) that operates using electricity (208) produced by fuel cell module.    USE - Operating method for heat transfer system (claimed) used to utilize heat produced by fuel cell module on and/or within aircraft.    ADVANTAGE - Enables utilization of thermal energy inn the form of heat produced by fuel cell module and/or heat stored in thermal energy storage module that includes phase-change material. Water cools thermal energy storage module to enable thermal energy storage module to absorb heat from the fuel cell module, and thermal energy storage module heats water for use in e.g. sink and/or coffee machine. Water discharged by the fuel cell module is converted into potable water by filter to facilitate increasing drinking quality of water channeled through the filter. An insulating layer circumscribes fuel cell module and/or thermal energy storage module to facilitate reducing heat loss to the ambient environment. Increases fuel cell efficiency for use in an airplane galley and/or reduces quantity of airplane generated power required to operate the airplane during flight. Facilitates decreasing an amount of power used by galleys through energy storage, use of combined heat and power from fuel cells, and efficient transfer of heat from fuel cell to galley insert loads.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a heat transfer system used to utilize heat produced by fuel cell module on and/or within aircraft.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic block diagram of a heat transfer system that utilizes heat stored in thermal energy storage module.    Fuel cell module (202)    Electricity (208)    Water pump (210)    Conduit (216)    Thermal energy storage module (218)