On Apr 5, 8:31*pm, DaleW > wrote:
> On Apr 5, 8:20*pm, DaleW > wrote:
>
>
>
> > On Apr 5, 6:04*pm, "Anders Tørneskog" >
> > wrote:
>
> > > "DaleW" > skrev i ...
> > > Interesting. I don't think the noise is a reason for concern, but 15
> > > years is a long time for those kind of compressors.
>
> > > Hmm, my fridge is 30years old, still working impeccably. *A different sort
> > > of compressor?
>
> > > Anders
>
> > Well, I'd assume a fridge (do you mean a regular fridge,or wine
> > fridge?) built in 1980 would have had Freon or other CFC. *But they
> > started phasing out CFCs about 20=25 years ago I believe so different
> > at least as far as coolant,
> > In any case 30 years for a fridge is certainly possible (my parents
> > had one as their extra fridge in their basement that was probably that
> > old) but not common. A lot depends on luck and load. A cooling unit in
> > Florida and las Vegas might well see more of a load that one in more
> > northerly climates (even if one has AC, it probably works harder than
> > a place where temps are colder)
> > The question is what happens if unit fails. If it's in a AC controlled
> > area and one doesn't travel, failure might not be a big deal. But if
> > one travels, and turns AC to 80 F when you're away, a 15 year old unit
> > failing could be *a real problems
> > I've heard of lots of wine units failing after only a few years.
> > Breezaire offers a full one year warranty, with 5 years parts.
>
> That was my offhand reply. But since posting I've pondered this
> slightly, and confused myself. Can one of the more tech/science types
> out there explain the differences between how a regular refrigerator,
> a wine cooler, and an air conditioner work? I know principles are the
> same, but there are obivious differences. *Thinking about it, I've
> never seen water collection for a refrigerator, though certainly I
> have for ACs. I've heard of ACs and wine coolers freezing up, but
> never a refrigerator. But on other hand ACs aim for low humidity,
> while wine cooling units want higher humidity. Doesn't directly answer
> Fred's question, but I'd love it if someone knowledgeable. could
> comment.

Most modern, popular, larger sized US brand kitchen refrigerators have
both a freezing compartment kept at 0 F or lower and a refrigerator
compartment kept just a few degrees above the freezing point of water.
The refrigeration coils are associated with the freezing compartment,
but usually hidden from view in modern design. Fans circulate air from
the freezing compartment and cooling coils(evaporator) into the
refrigerator compartment and back. Of course the cooling coils must
freeze over with ice, since they have to keep the freezer compartment
well below the freezing point of water. Nearly all of the larger
kitchen refrigerators are now self-defrosting. On a fixed schedule,
often 2-3 times a day, rather powerful heating elements are turned on
to melt ice build up around the cooling coils and elsewhere. Since the
fans are turned off for defrosting, hot air does not get circulated
very much. The water typically is routed to a large, shallow,
collection tray under the refrigerator. A fan blows on this collected
water to evaporate it into the room.

Large cold rooms work in much the same way as the self-defrosting
refrigerator. The cooling coils usually are mounted in an evaporator
unit with fans to circulate the cool air through the room. The
compressor unit is located elsewhere, outdoors, in an attic, etc.
Every so often heating elements come on to defrost the cooling coils
in the evaporator, and the water is drained away through a pipe.

Self-contained wine coolers sometimes also have heating elements to
melt ice. The heating elements are not needed in some designs since
the operating temperature of the room is much above the freezing point
of water. In any event, fans blow air over collected water and into
the room to re-introduce water that is condensed out by the cooling
coils. This allows somewhat imperfect humidity control.

In central home air conditioning, the evaporator is at some remote
location, and fans blow chilled air from the evaporator into ducts to
rooms in the house, and air is then returned to the evaporator. Here
the best way to control humidity is to use humidifier units that spray
fine jets of water into the air and can be set over a very wide range.

Finally, there is the room air conditioner that often is installed in
a window. The compressor part is outdoors, and a fan blows outside air
over the condenser coils of it to get rid of heat generated in
compression. The evaporator is indoors, and a fan circulates room air
over the cooling coils of it into the room. Water is collected at the
bottom of the room AC and goes into the part located outdoors There
the fan splashes much of the water over the compressor coils to help
cool them. Any excess water drips outside.

Evaporator coil ice buildup depends on several factors, some of which
are the type of refrigerant used, the charge pressure of the
refrigerant, the air flow rate over the evaporator coil, the humidity
of the air, etc. If the thermostat is set too low, the compressor is
running long, and the humidity is very high, then ice buildup is most
likely to become a problem. Most cooling units, regardless of type,
will specify a minimum and maximum temperature for which they are
designed. A typical window room air conditioner is not designed to
cool down to 55 to 60 F without freezing up in very humid weather when
the unit is running most of the time. This often can be overcome by
using a greatly over-sized window AC - I use one of about 18000 BTU
capacity for a small well insulated room. This AC normally would cool
several rooms in a house. Special thermostats designed for use in
liquids prevent very short on cycles that can damage an AC. An added
large fan greatly increases the airflow into the AC from the room.
Thus the AC may freeze some ice the short time it is on, but the high
velocity of the air from the added fan melts the ice during the off
cycle and blows much of the moisture back into the room. A small room
humidifier increases the humidity when needed, but it is not on very
often. In case of failure, I have a spare new AC that just slides into
the case mounted in the window. In case of extended power failure, I
have a generator capable of running the wine room AC and a wew other
essentials.

Modern kitchen refrigerators are different from in older ones in many
ways. Many different refrigerants have been used over the years
including sulfur dioxide, several types of freon, etc. Compressors
have largely been changed from a piston design to a rotary design. The
energy efficiency has been greatly increased. In some of these newer
designs, the compressor runs much of the time, and this might
contribute somewhat to a lower lifespan for the compressor than for
some past designs. There is also concern to reduce noise as much as
possible. Refrigerators differ considerably in failure rates for
different brands. However the inclusion of automatic ice makers and
running ice water can greatly increase the failure rate. After the
refrigerator is several years old, it often is cheaper to buy a new
refrigerator than to have the old one repaired, especially if the old
one is of low energy efficiency. One of the most reliable
refrigerators I have heard of was owned by a great uncle of mine. It
was a refrigerator that ran on natural gas. I do not know how long he
had it - at least 25 years, but that refrigerator outlasted him.