I post this question here as a starting point, because I am not sure which forum this question would best be answered in. If this isn't the best place for this question, please let me know. I have been puzzling over the lifting of water using heat, and see a few different methods that it can be done. However I am not sure what the limitations or efficiencies might be, and would like to determine the most efficient lifting method. The first method I envision is a model similar to the earth and how water is lifted into the atmosphere forming clouds, the second would be a model similar to a coffee percolator and a third would use something on the order of a rankine cycle pump to elevate the water. Any method of lifting would have to exist in a closed system where the temperatures at the lower elevation would be higher than the temperatures at the higher elevation, and that the temperatures at the lower elevation would not exceed 100C. Further, there will be a small Delta T difference between the lower and upper elevations and a difference in atmospheric pressure at the higher elevation which may be regulated between normal atmospheric pressure and 0 atmospheric pressure, and a heat exchanger to remove heat to accomodate the atmospheric vapor model of lifting water. Since it will be a closed system one can simply imagine two sealed tanks connected by a pipe or pipes with a heat source at the lower elevation to power the system. I am not asking here if this will be an efficient method of lifting water, I am simply asking what may be the MOST efficient method within the constraints of the model given.