Tuesday, August 22, 2017

Cool Air: $2600

     The A-coil in the air-conditioning system here at Roseholme Cottage has had a slow leak for at least three years now.  Each spring, that has caused it to super-cool, freeze up and it has taken an expensive topping-up to get it running again.

     It happened this Spring.  It also happened yesterday.  This morning, we had the HVAC tech out and he say's it's the A-coil, the one that lives in the ductwork above the furnace and chills the air.  Good news and not: you can still get them.  You can still get the R22 refrigerant this 20-year-old system uses, too -- for another couple of years.  But this whole thing is going to be an unloved orphan in a few years, if the phase-out proceeds as planned.     I could roll the dice, the current Administration isn't friendly to this kind of EPA meddling; but they're unlikely to be in place forever and the companies that make this stuff are mostly giant multi-nationals: R22 -- Freon plus a little of this and a dash of that -- is going away.  It's time to get away from it before everybody is having to and the price goes up.

     Which means Roseholme Cottage needs a new A-coil, a new outdoor unit and some fancy copper line.  And I'll be out $2600.00, American.

     Not fun -- I'm still feeling the pinch from the price of the car I bought a few years ago -- but it was not great sleeping last night and miserable trying to get ready this morning in the heat and humidity, despite open windows and electric fans.  It's got to be done.  What if Tam melted and I had to buy the Internet a replacement?  Way more expensive!  Besides, I've read the H. P. Lovecraft story and I'm not goin' out like that.

     This is actually a pretty good deal compared to the going rate in Indianapolis at this time of year.  They start work tomorrow morning.  Should take about half a day.

11 comments:

pigpen51 said...

Sorry for the huge bite in the wallet, but glad that you will have a more efficient and reliable system for the long run. I live in Michigan, and with our clouds, I forgot the major solar event until I drove past a group of people looking skyward with funny looking glasses on.
Back in 1979, I had been out of high school for a year, and so was a year into my 35 years of foundry work. I remember taking a quick break from pouring steel and stepping outside with a welders helmet to watch the eclipse back then. I don't remember the hype on television and radio for months ahead like this time. My daughter and her husband, her inlaws and my 3 year old grandson all drove from MI out to Nebraska to be there to watch the eclipse. Seems a little odd for a vacation, but my grandson is a John Deere nut, so they stopped at some museum for him, so I guess it was ok for him.

Stay cool, and best wishes for you mom.

Blackwing1 said...

I'll add my condolences on the occasion of the death of your A/C. The phase-out of R-12 and R-22 was a scam from the get-go, much like the current one on global "warming". The "ozone hole" was going to kill us all, and URGENT action was needed immediately since anything we did wasn't going to reverse the damage for 50 years. The last time I read anything about the polar vortex over Antarctica was about 5 years ago, mentioning that it was the smallest ever, had been barely measurable, and had closed up in "record" time. Well, since they'd only had the satellite up there monitoring it since 1979 they hadn't had much of a baseline on which to predict they imminent environmental disaster. Seems that everyone has forgotten the misplaced predictions of disaster.

But the government got to subsidize the heck out of DuPont's new refrigerant-manufacturing plant. Sigh.

I designed A/C's and heat exchangers (for cooling electronic enclosures) for 7 years in my first engineering job out of school. I'll give you one piece of advice if it's not already too late: Over-size the condenser side as compared to the indoor (evaporator) load size.

You want to just barely, slightly over-size the evaporator coil (the "A" coil) but not by much, because the system will then "short-cycle" and over-cool without reducing the humidity much. Right-sizing it means that it runs a fair amount of the time that you're calling for cooling on the thermostat, and keeping the coil nicely cool will condense out a lot of the humidity in the house.

In order to meet government efficiency standards another trick that A/C manufacturers use is to run very high evaporator coil temperatures in order to keep the evaporator pressure very high. Higher pressure means denser refrigerant vapor, and thus they can pump more massflow for a given volume flow. Lots of stuff the government has screwed up in home A/C, but that's the worst sin. They can no longer keep the indoor coil cold enough to remove anywhere near the same amount of water vapor as they used to.

But oversizing the compressor/condensing side won't have any adverse effect (except the incremental one on your already-thin pocketbook). What it DOES do is allow the condensing coil to run at much lower condensing pressures. Take a look at the P-h curve on the refrigerant they'll be using, and figure out what a 20F drop in condensing temperature does to the pressure. Remembering that the pumping power that the compressor is putting out is strongly dependent on the condensing pressure (and with a refrigerant at saturation those two go hand-in-hand) and a lower condensing temperature leads directly to long-term lower operating costs, by a lot. The small change in cost from (at a guess) a 2-ton unit to a 2-1/2 ton will be quickly re-paid over time.

Do this ONLY if the up-sized condensing unit has a bigger coil and/or a more powerful condensing-side fan (the outdoor unit). If not, all you'd be getting would be a bigger compressor (just by itself inside the unit) and that doesn't help lower the condensing pressure.

A nickel's worth of free advice, worth what you've paid for it.

Just as a side note, when we retrofitted our 1901 farmhouse with A/C I went with a Fujitsu mini-split system with D/C inverter variable-speed motors on everything (compressor, condensing fans, evaporator fans). So incredibly efficient they don't even qualify for the fed-dot-gov rebate money (that and the fact that they're all made in Japan). We can run one, two or all three indoor heads at different temperature set-points, and the condensing unit just puts out whatever is needed. Without any ducting in the house (hot-water radiators) it seemed to make the most sense.

New Jovian Thunderbolt said...

Tip jar, Ms. X? You know I'd hit that like a called fast ball in the middle of the strike zone.

Antibubba said...

A few window units and a dehumidifier aren't an option?

B said...

That is, actually a pretty (really a VERY) good price for a 3 ton unit, which is what I assume you have.

JayNola said...

I'm not sure anyone could afford the replacement cost on Tam. The cost in raw snarkium ore alone would be scandalous. And where would you get it refined to the requisite purity these days? The EPA shut down all the domestic lead smelters and that waste stream is nothing compared to the by-product from Tam grade snarkium pour.

Roberta X said...

NJT -- and anyone else with a yen to contribute -- Tam has a tip jar, and she lives here, will benefit from the air-conditioning, and will chip in...

Antibubba: window units are a serious security problem. The half-updated 1920s electrical wiring is another issue. I was just about to do some stuff with that when the A/C failed.

homebru said...


OK. Tamtip just hit. vy73.

Jeff in Indy said...

May I ask who's doing the work?
My old Sears unit is still kicking, but always looking for a good contractor.

Roberta X, remotely said...

Butler M-K. I have used them for years. Competent, friendly and unpretentious.

Will said...

Back in '05, I tried to dispose of a couple large cylinders (about 5' tall) of R-22 that my father had stored at his autobody shop. No idea why he had it. Only one place, a couple states away, was dealing in it, but the price offered might not have covered the shipping cost, so they stayed. Property sold a couple years later after he died. Wouldn't surprise me if they were still there, since there was such a limited market. IIRC, they would have broken it down to the separate gases, the largest which was R-12, I think.

IIRC, that ozone hole situation was a complete scam by Dupont, to sell their new R-134a gas, since the R-12 patent had expired. That new gas is hazardous, as it has killed people who breathe leaking fumes. R-12 was dangerous only when burned.