The hollow shaft auger does not allow the other half of the recovered btu to be used, namely the air through the radiator. Again that 1600+ cfm has doubled in temp from say 80 F ambient to about 160 F and will blow through the dryer (it's a big blow dryer, but not quite hot enough for shorter...
You guys are teaching me a lot. Way to go! But here is the unanswered question: What length of a tube is equal to the lenght of the more efficient finned tube. heat transfer question?
Thanks Mike, at least now i know where the costs are weighted. maybe I can find other quotes. Welding the finned tubes would likely be real tricky, but I might could do the housing and insulation myself and save some. CS might corrode quickly too, so I guess my choices are now pretty limited.
At 12#/hr that would ADD 1/4 # H2O per min to the 150 cfm.
So yes, I believe that an HX must be used because the evap of 6% H2O gfrom the sand down to a 1% level is a cooling effect and I do not want to increase the humidity of the drying air or condense water back into the sand as the temp...
Since the exhaust gas will contain lots of water from the combustion, i was reluctant to do that. If the temp is too low will the water then re-wet the sand? Will soot or unburnt hydrocarbons make the sand sticky? Fine screening is the next step and the whole point of drying is to assist...
I am new to the forum and not an engineer, just a science guy, but did see several threads on HXs so thought this might be considered.
Scenario: Hot air (<150F & 1600-2000 cfm) various engines/brands from the radiator of ~20 KW genset flows through the HX, which then uses exhaust heat 150 cfm...
