A gas turbine engine comprising a fan case, an inner fan casing and a cooling assembly comprising: a first heat source, at a first temperature; a first heat sink, at a second temperature; and a heat pump (118, 202) coupled to the first heat source and the first heat sink, wherein the heat pump (118, 202) is configured to convey a quantity of heat from the heat source through the heat pump (118, 202) and to the first heat sink characterized in that: the first heat sink, is coupled to the fan case or the inner fan casing of the gas turbine engine; and the gas turbine engine further comprises a thermoelectric generator electrically coupled to the heat pump, wherein the thermoelectric generator is configured to power the heat pump; wherein the thermoelectric generator is configured to have a first side coupled with a first fluid stream and a second side coupled with a second fluid stream, and wherein a temperature difference between the fluid streams enables the thermoelectric generator to power the heat pump; and wherein the thermoelectric generator is located within the inner fan casing, with the inner fan casing serving as a mounting surface for the generator, wherein a surface cooler heat exchanger is thermally coupled to the thermoelectric generator and mounted to an outer surface of the inner fan casing, and the first fluid stream is a bypass air stream passing over the inner fan casing, and wherein the first fluid stream passes through or past the surface cooler heat exchanger such that heat is conveyed to the first fluid stream. a first heat source, at a first temperature; a first heat sink, at a second temperature; and a heat pump (118, 202) coupled to the first heat source and the first heat sink, wherein the heat pump (118, 202) is configured to convey a quantity of heat from the heat source through the heat pump (118, 202) and to the first heat sink characterized in that: the first heat sink, is coupled to the fan case or the inner fan casing of the gas turbine engine; and the gas turbine engine further comprises a thermoelectric generator electrically coupled to the heat pump, wherein the thermoelectric generator is configured to power the heat pump; wherein the thermoelectric generator is configured to have a first side coupled with a first fluid stream and a second side coupled with a second fluid stream, and wherein a temperature difference between the fluid streams enables the thermoelectric generator to power the heat pump; and wherein the thermoelectric generator is located within the inner fan casing, with the inner fan casing serving as a mounting surface for the generator, wherein a surface cooler heat exchanger is thermally coupled to the thermoelectric generator and mounted to an outer surface of the inner fan casing, and the first fluid stream is a bypass air stream passing over the inner fan casing, and wherein the first fluid stream passes through or past the surface cooler heat exchanger such that heat is conveyed to the first fluid stream. the first heat sink, is coupled to the fan case or the inner fan casing of the gas turbine engine; and the gas turbine engine further comprises a thermoelectric generator electrically coupled to the heat pump, wherein the thermoelectric generator is configured to power the heat pump; wherein the thermoelectric generator is configured to have a first side coupled with a first fluid stream and a second side coupled with a second fluid stream, and wherein a temperature difference between the fluid streams enables the thermoelectric generator to power the heat pump; and wherein the thermoelectric generator is located within the inner fan casing, with the inner fan casing serving as a mounting surface for the generator, wherein a surface cooler heat exchanger is thermally coupled to the thermoelectric generator and mounted to an outer surface of the inner fan casing, and the first fluid stream is a bypass air stream passing over the inner fan casing, and wherein the first fluid stream passes through or past the surface cooler heat exchanger such that heat is conveyed to the first fluid stream.