Roger Long wrote:
Larry,
snip RV heat pump advice for sailors
I put this post quite well up on my mental list of the ten best posts
ever to the forum.

I would also add KUDOS to common sense, a commodity often absent from
gold plated boaters with unqualified aspirations to snobbery. Hint:
real snobs don't need bling.

As an unconcerned snob, far too snobbish to usually involve one's self
with stupid people, I have however been unavoidably forced to
contemplate some issues of stupidity WRT heating and cooling and
energy.

The question in this vein begs expression: why do not all air
conditioners include the obviously useful option of being reversible?
Why do people not insist on this option?

To use an air conditioner as a heating appliance seems to me to be so
basic an idea thet there must be a conspiracy of stupid marketing
people to not advertise this as an option to save energy for heating,
and of course, money.

If every a/c could be switched to a heat pump function the energy saved
in winter, spring and fall heating applications would surely be
significant on a national scale, even if all we did was to reverse the
mounting in our window units and control the heating function by
unplugging it. Pumping heat is cheaper than creating it.

Why does not every a/c unit include provision to use it as a heater?

It's a national scandal of stupidity, especially given the efficiency
placards we see on refrigerators, stoves, etc. It's a scandal because
the efficiency would figure so obviously in an energy short world, or
just in dollars spent for heat.

Possibly a reversible control panel would be cheaper than reversible
valving solenoids or manual valves, even if, as some will say, it won't
work in a cold winter because of the freon, etc, etc, it would be worth
it if you do the math, even if the freon used were a little more
expensive.

Sometimes and once again, CHEAP is BETTER. It is only stupidity that we
do not, did not start on this 50 years ago.

Terry K

"Terry K" wrote in news:1151068708.100276.227550
@m73g2000cwd.googlegroups.com:

Why does not every a/c unit include provision to use it as a heater?



Most have strip heaters in them, or have it an available option.....

A heat pump needs, well, heat to function well. Here in the South we
heat our homes with heat pumps. But, alas, they only work good down to
about 40F outside air temperature, then the evaporator (the outside unit
of the reversed cycle) starts to freeze up requiring us to temporarily
reverse it again to boil off the ice that forms on the outside coils.
They call it "Defrost Cycle". I've always called it "Freeze Your Ass
Cycle" as really COLD air comes out of my vents when it's going on.

Boats with heat pumps work great in Charleston because the water from the
Atlantic is always WARM, even in January. The water never gets below
about 50F for long, so the warm water pumping through the water-cooled
heat pump keeps it from freezing up. If a water-pumped heat pump ever
DOES freeze up, say from the creepy crawlers plugging up the seawater
strainer, for instance, or the seawater pump failing, an amazingly fast
block of ICE forms INSIDE the seawater heat exchanger, which is just
tubing, after all. This ice, of course, does what ice likes to do,
expand and rip open any "pipe" it freezes in, including the amazingly
expensive seawater heat exchanger.

Another reason I don't like it is the damned maintenance, especially
going to the boat in winter to clean the creepy crawlers out of the
strainer so often. Even in winter they colonize a strainer here as they
get sucked in. One good reason for that is the ones trapped in the
strainer are warmer than the ones outside the boat, I suspect. They seem
to relish in the warmth of the strainer.

Electric heat, heat strips, suffers from none of these problems. When's
the last time you took your electric heater apart to clean it out?
Mostly never?

Now, economics. Noone gives a rat! They're paying for dock space with
50A of 120VAC for a god-awful amount each month. If the electric bill on
the boat is $200/month or $20, who cares? Boaters with electric meters,
excepted, running strip heat in the boat simply drops marina profits.
It's cheap heat when someone else is paying for the power to run
it...especially if you factor in the boater's expense of heat pumps,
maintenance, the damned seawater pump that has a MTBF of 150 hours,
cleaning out strainers on a freezing, deserted dock on Feb 2nd in the
gale.

It's not an issue "Up Nawth", anyway. With a seawater temperature of
33F, the heat pump is nearly useless as its seawater heat exchanger
freezes below the water freezing point and it either has to do frequent
reverses of the cycle to deice it or just freeze it solid.....