a method and apparatus for creating temperature differences in columns of gases , liquids or solids in a closed system under the influence of gravity is used to provide energy in the form of electricity or heat . a temperature differential element , optionally a solid , liquid or gas , is suspended vertically in a chamber inside an enclosure . the chamber optionally is either evacuated , filled with fibers , powder or small spheres , or otherwise arranged to minimize the effects of convection currents and radiation . under the effect of gravity , the upper end of the temperature differential element becomes cooler than the lower end . a thermocouple can be used to generate electrical energy from the temperature difference between a vertical segment , for example the upper and lower ends , of the temperature differential element , or heat exchangers used to extract heat .