Glort,
Using the Lister to run an auto compressor is out- it's 400 far away, over a hill. Running the Lister as generator for a compressor is fine, since this is so rarely used. But it would be neat if I could use my inverter to handle it during the day...I could use it more often which seems to be the trend for the SW US.
Window AC units direct would be the obvious solution but I can't use them, for ELF magnetic fields, sound, air quality and wrecking the shielding that my home provides with it's fine stainless mesh screens over all the windows.
Bronco,
Your comments were thoughtful and right on the mark for a typical home in a typical setting.
Most conventional in floor heat systems in a concrete slab home are so badly designed that yes, for heating or cooling mostly you are trying to change the temperature of the earth and outdoors. My home is only 1100SF and is superinsulated, including the 5.5" thick slab. On a 100F day it gains 3-4 degrees. The house air temperature is 2-3 degrees above the slab temperature.
In floor cooling has been well tested in concrete in floor heat systems in a study paid for by New Mexico state. They were using night sky radiation via unglazed solar water panels on flat roofs to chill the water. Their goal was to just remove heat load from the building overnight...and this it did quite well and for very low cost.
After reading the reports from NM, at elevations similar to my own, I did some testing on night sky radiation/evaporation cooling via water trickled down steel roofing measuring delta temperature, temperature, humidity, wind and flow rate. It is viable but if there is no wind, and no clouds it requires a minimum collector area of 1000 SF for my 1100 SF home. That's a lot of corrogated steel roofing. If there are clouds, there is no night sky cooling so it is not a certain thing. Using the shop roof for night sky cooling would be possible but is hell on the roof since the well water is pretty high mineral content. I'd rather put the steel on racks just above the ground, which also removes head so a 20 watt DC pump would easily manage the water flow at the minimal lift needed.
My neighbor and I did some experimenting with running his 65F well water through his 900SF shop floor a few years ago. It worked so well when the slab temperature was 10 degrees and more above water temperature that when he was living in the shop during home construction he ran it every afternoon to cool off the shop. His shop and slab is also insulated but not nearly as good as his and my homes. Based on the flow rate and temperature rise, I did calculate that the typical BTU capacity of a 1.5 HP compressor was just adequate for my house. 65F water isn't really cold enough for a desired 72F...not enough delta T; you really want 55F water. Running it for 4 hrs during the middle of the (summer) day when I have excess PV capacity should suffice to lower my house temperature the necessary 3-4 degrees. My need would mostly be for June wildfires, where there is no shortage of PV power in the day. My battery system isn't designed for carrying 1200 watt loads at night.
I did monitor indoor temperature and humidity here during the intended cooling period of June through July and there is plenty of margin so no chance of sweating floors in my climate here. The floor mass is being cooled only a few degrees in a day... it will well above the dew point. As you noted, it is not possible to use in floor cooling in a more humid climate because of the floor condensation, and besides, dehumidification is much desired.
My concerns about window AC units converted to propane are- can they be used on fuel grade propane, and how do I insure the right type and amount of oil...and concerns about purging the original oil. I have 10 gallons of white mineral oil so of course that is an appealing lubricant.