Hey Folks-
My first opportunity to post here and after much searching I just can't find the answer I am looking for.
We are trying to develop a waste heat recovery system for low quality (under 300F) sources. As temps are low we can not use steam effectively.
Alternative working mediums such as propane, R410, ammonia, and silicone oils have been suggested and have been used successfully in larger system applications.
My question has to do with determining the force that the vaporized liquid will provide. Steam is pretty easy to find information about but these other fluids do not seem to have much info I can find, or maybe I just don't understand what I am seeing... Water expands by 1600 times at 1 bar providing a lot of force but the expansion of these other mediums eludes me.
Additional parameters, we are working in an area with an average ambient temp of about 82F for the cooling coil to reject heat into the air. Operational source temp will most likely be between 180F and 275F. Thus providing the 60C differential necessary for a rankine cycle system.
The gas will then be expanded through an expander, hopefully a scroll type or variant which will drive a small generator.
If I had my preference it would be the silicone oil material as the high initial cost is offset by the long life, inherent lubricating properties, low operating pressures, and non-corrosive nature of the medium.
My apologies that this is long, after reading here for a bit the first five posts always seem to be asking for more information. Thank you in advance for your thought and suggestions.
Paul
My first opportunity to post here and after much searching I just can't find the answer I am looking for.
We are trying to develop a waste heat recovery system for low quality (under 300F) sources. As temps are low we can not use steam effectively.
Alternative working mediums such as propane, R410, ammonia, and silicone oils have been suggested and have been used successfully in larger system applications.
My question has to do with determining the force that the vaporized liquid will provide. Steam is pretty easy to find information about but these other fluids do not seem to have much info I can find, or maybe I just don't understand what I am seeing... Water expands by 1600 times at 1 bar providing a lot of force but the expansion of these other mediums eludes me.
Additional parameters, we are working in an area with an average ambient temp of about 82F for the cooling coil to reject heat into the air. Operational source temp will most likely be between 180F and 275F. Thus providing the 60C differential necessary for a rankine cycle system.
The gas will then be expanded through an expander, hopefully a scroll type or variant which will drive a small generator.
If I had my preference it would be the silicone oil material as the high initial cost is offset by the long life, inherent lubricating properties, low operating pressures, and non-corrosive nature of the medium.
My apologies that this is long, after reading here for a bit the first five posts always seem to be asking for more information. Thank you in advance for your thought and suggestions.
Paul