nick pine wrote:
Do you ever run out? Does everyone pay the same?
I've never run out of hot water in this place. It's split equally.
No, not at all. Since everything is under pressure, the pump only
needs
to overcome the small friction loss in the pipe. You might use
Grainger's $102 5P428 1/35 HP pump, which draws less than 60 watts.
So the water comes in from the cold pipe under pressure, and hopefully
doesn't lose much pressure throughout the circuit. Then it goes through
this small pump and gets forced into the hot water pipe, which is at an
almost equal pressure?
The one problem with this is that if the hot water tank *does* fill up,
I don't have access to it. I will just have to dump the hot water
directly down the drain and take more cold water. What was the gallon
per minute flow rate you quoted early (ballpark figure is fine)? Take
that flow rate and compare it to the average hot water usage for a few
apartment residences. During showers or dishwashing, the two flow rates
might be comparable. But otherwise I think the hot water tank would
fill up very fast. Filling the hot water tank quickly is good, in one
sense, but afterwards I will probably be back to dumping nearly a
thousand pounds of water per hour down the drain pipe.
I could COMBINE that idea with the outdoor cooling circuit idea. But it
wouldn't be as simple as just redirecting the heated water outdoors. I
would also have to stop taking in cold water, and take in the water
which is returning from the outdoor cooling circuit. It would require
four solenoid valves, or two 3-way solenoid junctions. Now that's fine.
But the REAL disadvantage for me is that there are now two constraints:
- Must have piping going to the hot and cold water pipes
- Must have piping going outdoors
So now the AC is somewhere near a power outlet, and there are 4 rather
long tubes coming out of it. At any given time, water is moving through
only two of the tubes - one hot and one cold. It would work fine in a
basement, but it's a little much for an apartment (at least mine). In
my apartment, one side faces the outdoors (porch & windows on this
side) and the plumbing runs on the opposite side (kitchen & bathroom on
this side).
I'd be fine with putting the AC on either side. Meaning I'd use either
the outdoor cooling circuit idea or the hot water pipe idea. But I'd
rather not do both. For me, I think I'd prefer the outdoor cooling
circuit, just so that I didn't have to dump all that water down the
drain. I know, it's free for me, and I was considering it before. But
I've recently come to think that it is rather wasteful of resources.
Also, they might notice around 2 gpm * 1440 minutes per day = 2880
gallons per day of additional cold water usage.
Evaporation happens when water meets air. Underwater fins won't
"evaporate" water unless it boils, which would kill AC efficiency. To
evaporate quickly, the fins must be wet and exposed to lots of
airflow,
which sounds like a recipe for corrosion.
Well, here's what I was planning. The water would start off as steam,
then pass through the compressor, raising its boiling point (turns
liquid at a lower temperature). It would go through a condenser
(basically a radiator), where it would cool and turn liquid. It would
then head towards the hot fins of the indoor AC. When it got there, the
water tubing would enter a chamber which is hot (from the AC fins) and
is at a lower pressure (because the water would be expanding into a
larger volume). You're right that it would require a vacuum-tight seal.
But the fins wouldn't be underwater, and no outside air would pass
through them.
BTW: To avoid corrosion, maybe use glycol mixed with an anti-corrosive
agent instead of water.
How would you make a vacuum-tight seal around the hot fins?
I'm not sure. Some tight rubber gaskets around the refrigerant tubing
might work. Without a vacuum-tight seal, this evaporative water circuit
couldn't be used (at least not *directly*).
Awhile ago, I described an *indirect* approach for transferring heat
between two closed circuits (the liquid-liquid heat exchanger). But
I've since decided that is probably a poor method (performance
degredation).
Maybe instead of rubber gaskets, the chamber could be built around the
fins with a small clearance wherever the refrigerant tubing got in the
way. Then I could weld around all the clearances.
How would the heat get into the air?
The heat would dissapate from the tube into the air naturally; the
water (vapor) is hotter than the air. A standard radiator/condenser
would do the trick. A fan would help.
Can you explain further about the plastic films?
That wastes energy. Pushing hot water into the pipe is better.
Nick
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