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Aug 09, 2022
In Thermodynamics Forum
Could we build a four-stroke engine that runs on the exhaust heat of another engine? My idea is to have a four stroke engine suck in the exhaust from another running engine, instead of fresh air. Compress that hot exhaust on it’s compression stroke, then at TDC inject a burst of steam, through some kind of injector. The boiler water could be preheated by the cooling system of the first running engine. Does this sound at all feasible?
Apr 05, 2022
In Thermodynamics Forum
A while back a was messing around in the shop, and ended up making this water pump that uses only heat to pump. The two check valves are the only moving parts. Here is a video of it working... Here is a drawing of what it looks like inside... Here is another drawing of what I believe it is doing in its cycle.... The system is primed with water a bled of any air that may get trapped in the system. It’s starts to pump within 30 seconds of applying heat to the bottom of the pipe. I believe what’s going on is that a pocket of steam is formed at the bottom of the pipe. Being that there is no air or space for the steam to expand to, instead it pushes up on the water column and forces it through the outlet check valve, achieving its expansion that way. Once the steam no longer has the energy required to continue pushing the water column, the outlet valve closes, and the pocket of steam begins to cool, having lost a good portion of its energy. Asthe steam cools in begins to contract a form a partial vacuum in the bottom of the tube. This vacuum in turn opens the inlet check valve which supplies more water to fill the voided space in the unit. The cycle then continues. I believe it has to be using the Rankine cycle, but when I try to draw out a rough and dirty PV diagram I kind of run into a bit of a wall and get nowhere. Can anyone explain what’s going on here a little better to me? Perhaps what I think is going on is completely wrong and somebody else has a better idea that would help me understand more. Thanks for any replies!
Does this water pumping device use the Rankine cycle? content media
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