Salutations:
I been looking into this, the patent still exists and as near as I can figure the inventor is alive and well in FLA somewhere.. Butnow web-pages I can find..
The Pop Sci report says that Bendix was close to working out a filter for ice output and that it was envisioned as a good heater too by redirecting air-out ports to draw air off the heat exchanger while cooling the great outdoors.. (It kinda sounds like a two way heat pump) .. Chrysler was courting it in '73, as was the US airforce for Tomcat program.. It was also thought it would be good food reefer as it didn't dry out the air as part of it's function - hence ice on the output..
As near as I can figure, the '73 device was using a vanes rotary compressor (kinda like a super charger) which on one side pressed 30 psi directly into a small port and copper pipe to heat-exchanger (an expensive rad), which absorbed the heat as the air expanded - then passed it back to the other side of the compressor through a much larger port to cool the vanes a bit and then out a pipe to cool you and me..
I'm guessing that they did it this way to increase out bound air pressure and to cool the vanes compressor in one cycle.. The device would not seem to include a dash blower fan, so any cool breeze out of the dash would be limited to what the second stage could push out.. Of course, for heater function this wouldn't be problem..
If Bendix people didn't work out Ice filter, it must have had some reliability problems if ice started to form on the compressor walls and the vanes.. He was gapping the vanes so they didn't completely touch the walls of the compressor..
So it must have needed a very specific rate of flow at 30psi so as not to ice the walls and vanes at a greater rate than the heat stored in the vanes as part of the original half of the compression cycle could melt it. It could then convert any ice in the compressor back to liquid on the fly, but it had to be balanced flow so that it didn't re-heat the air too much..
It is the only thing I can figure as to why it passes through compressor twice.. Also, they must have had to engineer some sort of humidity control process at the intake of the unit to allow for consistant inbound air qualities despite changes in air-density and damp weather..
I have been considering it and I think that they bailed because they couldn't manage a real high CFM rate without big (high amperage) compressor (like when you turn on your dash air on 'MAX').. To get even a basic CFM rate, you'd still need to be pushing a lot of air in at 30 psi to get cool breeze out.. which would still make the unit large an kinda bulky compared to distributed traditional sealed air-conditioner unit and dash fan..
So, So, So..
PO put in a older and smaller Propane/Electric fridge some time back and left big enough space over the fridge to put in a good sized micro-wave.. I was looking at now empty space and wondering about about a dropping a small basement air conditioner up there.. Then I looked at cool-cat heat pump and had a brain fart that went.. 'Hey, I don't need big CFM if I can run this stationary on DC.. It just has to work evenly through the day'.. took another drag on the funny cigarette..
So.. What I'm looking for is a silent 40psi compressor - a way to dehumidify the inbound air, a really efficient DC motor capable of spinning fairly fast at set rate and a box that is shaped so that the ice is formed on a ductwork that shares waste heat-exchanger chimney.. and a couple of lengths of hose to drop water from dehumidifier and duct.. And space to put it all in and vent it..
When I upgraded the Onan, I dropped in 3 big 30 amp deep cycle 12v camper batteries.. so Lots of DC and a honking great generator to keep them topped up..
What should I find above the fridge? A huge chimney for the propane fridge that could be ducted into to move a lot more hot air from a heat exchanger.. and enough room on the roof to put mini chimney in for propane fridge.. Indeed, as I have dumped DOA roof-air/goiter - I still have all the basic Duo-Therm plumbing to do exchanger and maybe dehumidifier.. (compressor and seals and control board seemed cooked - but fan works like a top).. I even have free AC wiring if I can't work out DC..
I'll report in if I start working up drawing and bugging people for details.. Any thoughts or sources would be appreciated as always.. The Electrolux is cowering in the basement even as I drop this note to listserver..
your pal
J Dexter
