Mixing alcohol with water as the working fluid of a boiler would reduce the amount of heat needed to get the same pressures from the boiler. A Organic Rankine Cycle is when they use a condenser to convert the steam from a boiler back into liquid and pump it back into the boiler. Obviously if you were to use 100% alcohol as working fluid you would want to use the Rankine cycle so you aren't allowing flammable gas everywhere. I found some information on experiments with differrent working fluids in boilers most around the turn of the century and no word the amount of energy burned to create pressures, just that they were generally low pressure systems. Here's a Rankine cycle that I invented: Please Register or Log in to view the hidden image!