Abstract: The invention relates to the using of low temperature heat for the production of electrical energy by using of supercritical carbon dioxide as working fluid. It included a process and a device for process realizing with higher efficiency in relation to other known processes and with a wide temperature working range. This is related to a wider adjustability which allows an optimal operation both in summer and in winter operation without technical or constructional changes. The process is realizable without damages to the environment and is realizable with low effort. The relative emission of carbon dioxide is reduced in relation to other processes. Low temperature heat from a given heat source (1) is taken off by carbon dioxide at high supercritical pressure as heat transfer and working fluid in the process. Then the heated fluid is expanding in an expansion machine (2), which is connected with a generator (3) for the production of electric power.