Question:
The A/C system in an `89 old Honda is completely dead. They
quoted a price of about $1500 to fix but the car's worth as much as
that. I like to put in a 700 watt 117V portable or standard home air
conditioner in the trunk but worry it may drain the battery. Is it
possible to make a difference by continuously pumping chilled
waters (filled with icicles) into the entire liquid line (tube) that runs
thru the evaporator?
Answer:
On the input side, we can do another finite-napkin model and figure
that after accounting for inefficiencies, you're using 1400 W, at 14
V, which comes out to 100 A. That's a lot of current; you'd want to
run a husky wire, fused at the battery end, like the kids with the
enormous stereos have to do. It also represents a very large
fraction of a typical car's alternator output. These arguments still
apply even if you look at things more closely and decide that my
safety margins are too large.
Finally, you have to expose the home air conditioner's coils to the
outside world or else you're defeating your own purpose by dumping
that excess heat into the cabin. And don't forget to support it very
solidly.
You might be better off getting an ice chest and some of those quilted
blankets of "blue ice" and making cold packs for your body. This
would at least be tidier than what I had to do on a trip across the
Mojave when my air conditioner went on the blink -- an ice chest full
of ice water, into which I could dip a towel for my head and neck and
shoulders.
