Refrigerator monitor ideas?

Do you know how much electricity it consumes?

Excellent information. I'm assuming you've measured the temperature changes or power usage to determine the defrost time. I seem to recall it was more variable in my unit than I expected. You've confirmed, however, what I am looking for is a way to detect a "warm up" that's not followed by a cold enough "cool down" within a specific time frame. Why did I think you were using ADI and/or HAI gear?

Great! Exceptionally useful. Thanks. On a practical note, how did you run the wires to the probe and where did you locate it in the unit?

-- Bobby G.

Yes, if you've read down to the bitter end I reached that same conclusion. Inspect it when I inspect the furnace filter *or* when the furnace filter whistle sounds. But where's the home automation fun in manual inspections? (-:

In defense of John, his method is very useful for detecting far more than problems than the ice dams I experience due to dog hair build-up. One of the very smart rat terriers has already learned that's where her food lives and how to open the door. Although it's hung to automatically close, if she drags something out of it, the door sometimes remains ajar. John's methodology would be very useful for detecting those sorts of bad events and I intend to implent his suggestion as well as a cheap LCD battery thermometer with a remote probe and a high temperature alarm.

Now, does anyone know of a dog-proof aftermarket refrigerator lock!

-- Bobby G.

(-: Float on what? Water? Nanogoo? Lava?

One hundred years from now there will still be a PC running Windows 98 and a light being turned on and off by X-10 *somewhere* in the world. How much of that world will be underwater is anybody's guess but some of the estimates I've seen look *very* bad indeed.

-- Bobby G.

There's an audible warning device in the cockpit of almost every airplane called a "stall warning." Of course, by the time that one goes off the icing problem is pretty bad. :^)

There are two methods I'm aware of. Some use engine heat to warm the leading edge of the wing. Others use pneumatic boots to break it off. There are three main types of sensors to detect wing ice -- magnetostrictive, electromagnetic, and ultrasonic.

Magnetostrictive sensors use a vibrating coil. As ice accumulates the frequency of the vibration decreases, signaling the pilot and (in some systems) automatically inflating the deicing boots.

The space shuttle uses an electromagnetic device called a resonant microstrip patch antenna. There's an article on it at

Wing ice is a major problem. It can build up very fast when conditions are right for it.

That is not what happened. It was a 737. The pilot made several mistakes. First, he used reverse thrusters to try to push back because the airplane's wheels were bogged in heavy snow at the ramp. Then he tried using the hot exhaust of the airliner ahead of him to melt ice on his own wings. Instead of removing the ice, it allowed the water to refreeze on the trailing edges of his wings. The deice boots on a 737 don't help with ice on the trailing edges but that would not have mattered anyway. The pilot didn't even use his deicing system on or before takeoff. The first officer repeatedly told the pilot they were in trouble (or words to that effect) but he refused to listen.

Using reverse thrusters inappropriately may have been a contributing factor. The engines sucked in a lot of storm debris (ice, snow, etc.) at the gate. That reduced the available power. Low power combined with ice-laiden wings caused a stall on take-off. BTW, for those who don't already know it, when an airplane is said to have "stalled" it does not mean the engine stopped. It means that the wing has stopped generating sufficient lift to maintain flight.

Someone I know claims to have snap-rolled a brand new 737 at low altitude after having borrowed same from Boeing. :^)

Hmm. Dog outside freezer... problem. Dog inside freezer... no problem.

Yep. Securitron makes magnetic locks in 600, 1,200 and 3,000 lb ratings. The lightest would keep most any dog out. The largest would keep anyone but Mama Cass at bay.

You could also mount a bent gate hasp, purchased at HD for $2, on top of the fridge. The door won't open unless you first lift the hasp. That's cheaper and simpler than a Maglock but nowhere near as much fun. :^)

Yes, I was an ADI user, until the tornado ;-( Let me know if you're in the market for any ADI stuff.

I currently use an Elk M1G and HomevisionPro. The TS300 is connected to a zone on the Elk and the Elk sends a message to the HV unit when the TS300 high limit is exceeded, and another message when the temperature is back below the high limit.

On average I get one set of entries per day in my log. My log is a POS printer - haven't gotten around to starting up Homeseer again. The time the freezer is above minimum temperature varies from 5-20 minutes. I'm guessing this has to do with how many times the freezer has been opened during the day. Normally the temp is 0 degrees and I have the TS300 set to a high limit of 15 degrees F.

The remote temperature sensor for the TS300 is on a long cable - probably around 7' IIRC. I just stick it in the door on the hinge side and try to bury it near the back so it doesn't trip every time the door is open for a few minutes. The TS300 is mounted on the wall near the freezer and shows ambient temperature, and freezer temp if you press a button on the unit. You can set high and low llimits for the TS300 sensor and the remote sensor. It even has an internal sounder that can be enabled.

would not have mattered anyway.

A 737 doesn't have "deice boots", ninny. It uses bleed air from the engine compressors which is piped through ducts that exit along the leading edges of the wings and horizontal stabilizer. In flight the system is very efficient (and prevents ice buildup on the wings and trailing edge surfaces). On the ground the airflow from the ducts doesn't go very far and further reduces the power available for takeoff. The engine intakes are also heated with bleed air as well as re-circulated engine oil (but to a very limited extent). The fuel is also heated before it enters the engine nacelle. It makes it much easier to vapourize in the combustion cans. The same goes for the hydraulic fluid which powers flight controls (it's also recirculated to keep it warm).

after having borrowed same from Boeing. :^)

The "someone you know" never claimed any such thing, but the someone I know claims not to have pirated software on his website (more specifically "his" server) and yet, it's there. Tsk!

Hey, I didn't bring it up. I worry when *you* worry about how *I* spend

I'll deal with those comments separately. For now, I can assure you it ain't happening.

I don't. I was *very* suspicious of that reading being a "full swing" operational wattage. But I didn't say that represented anything but a single reading of an unknown state. I've also seen readings of 62 watts and

What I don't know is how much of that energy is not purely waste but is contributing to warming the house. Nor do I have any way of knowing what the total cost of ownership and operation for a new box will be. But I've heard enough stories like Dan's to know that total cost of ownership is likely to be a lot higher than most people would expect based solely on energy efficiency cost benefit tables. Especially those prepared by entities with vested interests.

I also know that this humble old Westie reefer tolerates a very wide swing of temperatures and humidities in the basement while maintaining a remarkably stable internal temperature. If I wasn't such a lazy SOB, I would just inspect and clean more it often now that I know there's a dog hair issue. Since the dogs have increased the airborne debris load for everything that "aspirates" I've had to bump the inspection schedules of all items that have fans or passive cooling ports. If I had a sensor, I wouldn't have been caught by surprise this last time.

Bill, you need to read more carefully before you fire off a comment. I clearly said "lots of metal in the MECHANICALS." Plastic shelves that cracked can be glued. Plastic cams or gears that crack bring down the entire system. A 17' unit made out of stainless steel would weight about ton and cost $5000. (-: I often find myself breaking down modern appliances and thinking "I wouldn't have made *that* part out of plastic." I understand why the refrigerator shell has to be plastic, but when I see plastic parts near heat sources I know there's going to be trouble. It seems as if designers 30 or 40 years ago built things to last as long as they could. Now, they seem to build things to last at least one year, but no more than ten. That experience contributes to my reluctance to replace new for old.

That might work, but it would require careful analysis and sensor placement to make sure that the low flow trickling didn't cause bad readings.

Yes, I agree with the problems you've noted with detecting flow in a small gravity fed system. The big problem with many of the suggestions is that I'd have to simulate the freeze-up events to make sure I was reading the probes and their meaning correctly. As Bill F. noted, periodic inspection would consume far less time and effort since once every 9 months should do it. I do like the idea of monitoring the temperature of "reference" items in both the freezer and the refrigerator and will be implementing that as soon as I figure out the best way to run the wires and place the sensors.

It's a very hard equation to solve because you can keep finding factors that need optimizing, even if it's the well-being of appliance store employees and junkyard owners. (-:

-- Bobby G.

It would be interesting to see what your Kill A Watt meter shows for 24 hours in kWh mode. You could then calculate annual kWh and compare it to the hypothetical figures bandied about by bureaucrats and ivory tower academics.

Icing on the ground has the problem of being over larger areas than can be handled by airplanes equipment. Airports in areas prone to this have deicing areas where they can wash down the plane with ice removing materials. The problem is then the time between the deicing and taking off so they can get above the problem.

When they added a new runway to Minneapolis St Paul International (MSP), they also built new deicing pads at the taxiway ends by each runway. That way, they can do the deicing after planes do any waiting on a backed up taxiway and shortly before they get in the air.

Public TV had a special on about a crash of a British jet that ran into another while taking off because the pilot (who happened to be the chief training officer) was really intent on getting home after the airport had been shut down due to weather. He ended up getting onto the runway without proper clearance (ignoring the copilots complaints about the flagrant rule violation) and hitting a plane that was landing. They discussed the change in the hierarchy policies that came after that so that the removed the "chain of command" attitude between the two pilots and made the copilot into additional eyes and brain power for the pilot instead of just a back up flunky.

but first she would have to get out of the box she is in....

magnetostrictive,

are right for it.

While I agree it's not listed as the main cause of the accident, there's a copy of the report at:

"The relief operator proceeded to deice the right side of the aircraft with heated water followed by a finish anti-ice coat of 20 to 30 percent glycol and 70 to 80 percent water, also heated. He based these proportions on information that the ambient temperature was 28F. (The actual temperature was 24 F.)"

I interpret that statement to mean the deicer the relief man applied was too dilute for the actual air temperature. I recall vividly the Potomac being nearly frozen over, which means the plane had probably was even colder than ambient, having cold soaked all night. IIRC, it was a brutally cold snap with temperatures in the single digits, which was very unusual for Washington, DC. There's page after page of detailed information about the deicer composition, application and testing but I think if you miss the freezing point you're screwed.

Anyone who's used standard windshield deicer in New England knows at a certain temperature, you're just adding more slush to the windshield if there's not enough alcohol in the mix.

after having borrowed same from Boeing. :^)

You just *know* that's going to generate flames. Don't we have enough of that crap?

)-:

-- Bobby G.

Nothign about the stall indicator allows it to detect airframe icing. In fact, when picking up ice, a mechanical stall vane is likely to have ice in it and no longer work as intended. A pressure-based stall indicator is likely to be clogged by ice and be unable to detect the drop in pressure that makes it function.

Loss of function of the stall vane (as well as your pitot-statics, of course) is one of the concerns.

:-P

I don't know about snap rolling a 737, but I do know you can trim them up for inverted flight. Doesn't even require full thrust! This is, of course, assuming a certain level of accuracy in MS Flightsim.

I'm past "flaming" him for lying. I never "claimed" to have snap-rolled a 737 (or borrowed one from Boeing). I was merely an observer.

Of course he knows, why do you think he does it?

Doug

RTOFL Hypothetical? One article I mentioned presents data from detailed, time-averaged field measurement of the actual in-home power usage of 5000 refrigerators in daily use in the metro area in which Dave lives. With an emphasis on older units and low-income housing, it might even include actual measurements of a certain curmudgeon's fridge ;-)

...Marc Marc_F_Hult

That's true, and by the time you hear it it's usually too late anyway (as Bass pointed out)

The "stall warning" in a Boeing 737 is also linked to the control yoke. It's called the "stick shaker". I seem to recall listening to the cockpit voice recorder for the Potomac Crash and you could hear the shaker in the background so the "stall warning" was definitely functioning.

The pitot tubes are heated electrically. That's actually on the pre-take-off checklist (along with turning on the windshield heat).

Flightsim's are fun. What's really cool is getting the chance to "play" in the actual full motion simulators. :-)

Sure. Whatcha got that isn't storm damaged?! (-:

Unfortunately I don't know enough about Elk programming to determine how easy it would be implement. As you may recall, C-Max and I are not best friends and I am loathe to make any changes to it because it's made me pay dearly for the most minute of code changes. The power and peril of ladder logic.

Interesting. Why? Not needed? Not enough time? More important projects?

I've been monitoring the freezer temp at dead center of a full freezer and it swings quite a bit. It "damps out" fairly quickly, but I'm worried that a door left open for a minute will trip it. Around here, a door can easily be accidentally open for that long, because these rescued pups are smart and know *precisely* when to make their "max mischief" move. Just today I made the mistake of taking a phone call during morning roundup and the one I call "Hot Spot" (but my wife calls Matilda) scooted off into the closet to make a deposit. I wasn't watching her for all of ten seconds and she knew it and ran. I'd pay $150 for a collar that could give me 30 seconds of warning that the dog's bomb bay doors or ballast tanks are about to open.

I was thinking of drilling through the back of the freezer compartment to eliminate wires inside the box. My wife uses the Westie to store dog food and meds and she's already made it clear how she feels about wires in the bathroom, near the sink or in the refrigerator!

Very nice features. Now that you've described how nice it is, I'll bet I'll be bidding against some fellow CHA'ers when the next one comes up on Ebay. (-: In the meantime, I think I can hack into a cheapo remote sensor LCD alarm thermometer I have and provide contact closure when the internal buzzer sounds. Wall mounted near the fridge, it will provide very similar functionality (I hope). It's probably a project worth documenting since everyone's had a fridge foul up on them at one time or another.

-- Bobby G.