i have been kicking around a system such as this
take a compressor driving r22 or even propane in an outbuilding that is well ventilated if
propane is used (i have a sanden rotary mounted and belted on my trigernator waiting for connection
when it is placed in service)
because the compressor is engine drive, i would put my air intake down to floor level, let it vacuum up
any leaks should there be any. (if propane is used as a refrigerant)
use the cooling to make perhaps 500 gallons of cold (if not slushy water or brine, perhaps even ice if possible)
then pump the cold water into the air handlers inside the living space.
i figure a couple things are in the plus column
1. safety from leaks
2. ease of splitting cooling for zones without ducts
3. storage of cold for use when the engine is not running, which allows the engine to run under a higher
and more efficient loading when it is running, and be able to provide for other AC and DC loads while running
so the water tank becomes a BTU battery bank of sorts, and
4. the system could be reversed and store hot water for space heating in winter
i ran the calcs a couple years back and it appears in a superinsulated home i need 1 gallon of slushy water for each square foot of
living space i am trying to cool. so maybe i make my tank big enough to provide for 2 gallons per sq/ft and then start the process of
testing to find the exact volume to space ratio vs engine run time. and maybe on really hot days i shutdown other areas that don't need cooling so as to maximize the efficiency of the system.
years ago this was a very popular method of cooling churches, where a very small (relatively) compressor drive made ice all week to
provide cooling for the church on sundays for a few hours.. as we know churches have lots of windows, lots of folks coming in
horrendously high volumes of heat to remove, no insulation to speak of, generally insufficient shading, etc.
fwiw, the beauty of an engine driven system is not only the ability to drive a compressor system, but the ability to drive an absorption
system off the exhaust heat in the summertime as well, a time when the exhaust heat would generally be of no use for space heating.
so coupling an engine driven compressor with an exhaust heat absorption system overall efficiency would be very good, especially if one could also make use of and/or store the waste products (electricity and hot water from the coolant)
other technologies are useful when scaled down as well, for instance the cooling tower
a decent cooling tower will cool water ~10 degree's below ambient, so you wait to recool your btu battery return water
till after midnite when the ambient outdoor temps are generally at their lowest, drop as much temp as possible within
the time available and then start the engine drive up perhaps an hour before breakfast so you have electrical power, hot water for
a shower and time for the chilling to get a head start on things.
i also have and have considered using a thermoking refer unit for bulk cooling, such that if i come home at the end of the day
and it is hotter than hell in the house, i can simply start the Tking and drop the internal temp in a hurry. allowing the Tking to do
what it does best would take a huge load off the basic chiller system which could them be turned on to maintain temps.
i think there is a lot of very interesting things that can be done successfully if one can get his mind around a smaller superinsulated house
that are much more difficult to do in a McMansion that is poorly sited, no shade, millions of windows and little to no insulation.
i know i have lived in houses that would tax a 25/2 just to cool in the middle of july or august, just as i have lived in one that
a 3/1 would probably been adequate.
certainly a small highly efficient superinsulated home has some interesting possibilities.
btw, there is no reason why one could not use the first chill for driving a holdover plate for a freezer/refrigerator
r22 gets so cold that the return pressure drops very low causing seals to leak on the compressor in such systems anyway
so drive the holdover plate first and then expand the r22 in the thermal btu battery, this would take away all the available cooling
and in the process the return pressure would be above ambient so the seals would do as they were designed in the compressor.
personally i think airconditioning is a noble use for a listeroid/chanfa/X engine, as a heat pump the COP can be very high
compared to just producing electrical power
bob g