Question:
I am sure most people are familiar with gas powered refrigerators. I
was wondering if instead of heat from a flame, you used the heat from the
exaust mainifold of an engine. You could create an air conditioner that used
no mechanical parts and no additional fuel when in use.
I am aware that gas refrigerators use a combination of ammonia and
hydrogen and could create a hazard in an accident. I do not think a gas
refrigerator works too well when it is jostled around either. However, I would
think there would be some combination of materials that could be used.
May someone with a little more knowledge in this area might have some
thoughts.
Answer:
That's a possibility. A few thoughts though:
1) Ammonia isn't too bad of a chemical, but Hydrogen is. It's pretty explosive.
In a gas powered refrigerator, they can make the entire system very sealed. This
would be harder in an automobile. Compare this with refrigerators vs. car air
conditioners. Most of the refrigerators in the world are R12 units. But, they
hold their charge of refrigerant for decades. This is because the unit is a
completely sealed unit -- no rubber hoses, only copper. The compressor is a
sealed unit - there aren't shaft seals to leak. I suspect that it would be quite
difficult to make an automotive unit sufficiently sealed so that the hydrogen
doesn't leak out.
2) Gas powered refrigerators use the Servel cycle. There are three parts of this
cycle that rely on the unit being relatively stationary:
a) The water seal between the absorber and the separator.
b) The water seal between the evaporator and the condenser.
c) The "percolator" that lifts the ammonia and the water from the generator to
the separator.
