As we know, at present, power generation is a production process of converting, using a power generation device, thermal energy and nuclear energy of petrochemical fuel (such as coal, oil and natural gas) into electrical energy supplied for needs of various departments of national economy and people's life. However, petrochemical fuel can produce large amounts of carbon dioxide, which exacerbates the global greenhouse effect. Besides, nuclear energy faces great challenges of source of raw materials and environmental protection.
Those skilled in the art have begun to use solar energy, wind energy, geothermal energy, water energy (including marine energy) and other clean energies for power generation. However, solar energy and wind energy are seriously affected by climatic conditions, and geothermal energy and water energy (including ocean energy) are subject to harsh geographical conditions as well. Therefore, these energies cannot be popularized on a large scale. Furthermore, long-term development of the ocean energy is prone to result in ecological disasters.
Therefore, a kind of energy which is cheap and can be widely collected is needed. As a result, ubiquitous air, oceans, lakes and rivers come into people's sight. As all the energies on the surface of the earth substantially come from the sun (energy caused by volcanic eruption is relatively weak and can be negligible), the energy of the sun's rays is heating air, oceans, lakes and rivers all the time. If the energy can be extracted for human use, it will no longer have the problem of emissions of carbon dioxide, ecological disasters and the problem of scarcity of resources. Besides, the energy will no longer be subject to climatic conditions and geographical conditions.
For the above reasons, a variety of power generation devices making use of air or liquid have been developed, where air or liquid thermal energy is used to make working fluids having a low boiling point in a vessel be gasified, and then high pressure steam generated is used to drive a generator to generate power through a turbine. However, at present, such devices are basically required to realize liquefaction recycling of the working fluids by means of a refrigeration compressor and a booster pump. The problems lie in that, on one hand, as the refrigeration needs to face enormous liquefaction potential, it is infeasible to use the refrigeration compressor to liquefy the working fluids, and on the other hand, even if there is a ready-made cold source, using the booster pump to make the working fluids back into a high pressure area costs highly. Therefore, the devices have too low overall efficiency and cannot be applied in practice. In addition, such devices have special requirements on working conditions, that is, they require a temperature difference, and the greater temperature difference the better. The devices cannot work in the case of no temperature difference. In view of the above situations, it is necessary to improve the power generation devices, to improve the efficiency of power generation and finally realize all-weather, all-earth and full-time power generation and even provide power under no temperature difference conditions.