
h a l f b a k e r y
Like a magnifying lens, only with rocks.



account: browse anonymously, or get an account and write.



Constant-Noise Refrigerator

No spooky "on" and "off" noises
  [vote for,

This is a standard refrigerator combined with a noisemaker. Whenever the refrigerator compressor turns off, the noisemaker turns on, preventing you from noticing a change in sound. When the compressor turns back on, the noisemaker shuts itself off, and you never become aware that your refrigerator has turned back on.

This technology would be especially useful for basement oil burners. There is sometimes nothing scarier than the low, gaseous bellows of the oil burner turning itself on at night. A noisemaker built into the burner would ensure that you always hear a constant hum, and hence are not subject to spooky changes which convince you monsters are downstairs.

In both cases, the noisemaker would want to "calibrate" itself by recording the standard sounds of the appliance in operating state. When the appliance turns off, the noisemaker will gradually implement this recording, increasing the volume so as to maintain a constant decibel and frequency-spectrum output.

[Thanks to my friend Caroline for this idea]

phundug, Nov 26 2003


       Bun for you and your friend Caroline to share. Excellent idea. I want one for my boiler.
dobtabulous, Nov 26 2003

       Seems silly to add noise. I say you reduce the current noise and make it constant. Add a variable speed drive to your refrigerator and a proportional control system. You'll get the thing to run all of the time at a lower level, and just run faster when the door's been open for a while (yet not up to it's current level). Even then it won't "kick on", but slowly ramp up to a louder state, then slowly ramp back down.
Worldgineer, Nov 26 2003

       [Worldgineer] Can you do that to a standard compressor, or would you need something slighlty more complicated. What would a VSD control in a small 'fridge system?. Just asking.
I bun the premise as I personally can sleep in any amount of background noise but hate the on/off sequencing (even the ticking of a clock!).
gnomethang, Nov 26 2003

       Useful for me. I am very sensitive to any sort of changes in background droning noise.
waugsqueke, Nov 26 2003

       [gt] The refrigeration system wouldn't need to change, just the speed of the compressor - the system should work just fine at differing speeds. Really the only thing to controll in a refrigerator is the compressor motor - this would be run by VSD. If you meant to ask what the controll would be based on, then the answer is it would be run proportionally to the temperature difference between the thermostat setpoint (the knob that says <-colder warmer->) and the temperature in the refrigerator. The larger the difference, the faster the motor.   

       Oh, and I've even had to remove the batteries of a clock downstairs and across the house from me so I also appreciate this idea.
Worldgineer, Nov 26 2003

       You will need something to mask the switching noise when the compressor comes on. That's what really drives me nuts in window AC units, even if the fan is on at all times. Perhaps something that simulates an on-off cycle every few seconds.
kbecker, Nov 26 2003

       You could turn the telly up so it drowns out the rest of the noise and doze off blissfully unaware of the switching-on-and-off noises. I find the snooker programmes particularly good for this. But be careful not to stack old newspapers over the heat-exhaust vents if you live downstairs from [DrCurry]!
dobtabulous, Nov 27 2003

       Rods Tiger, Air Conditioner Salesman: "...and this, sir is the latest 'Brian Eno' model..."
hippo, Nov 27 2003

       Simple solution, phase cancelling generator. This was baked by several companies (Sennheiser, JBL) for aircraft pilot headphones and such.
Just apply a speaker and small amp to the bottom of the refrigerator with a pre-amp that simply gets its input from a microphone placed near the offending compressor and simply inverts the wave form.Two waves 180 degrees out of phase cancel each other and no sound is heard.
Slightly more complex than this but the basic idea is here and well known.
soundman, Nov 27 2003

       Thanks [Worldgineer}. I only ever control condensor fans on chillers to regulate head pressure and occasional solenoids (e.g. hot gas bypass under low ambient). I am basically a BMS/Controls engineer and NOT a fridge bloke so I have never regulated a compressor motor (usually left to others). The concept of PI(D) control is not unknown to me though.
gnomethang, Nov 27 2003

       Good, [phundug]. +
k_sra, Nov 27 2003

       No need for a continuous noise source. Just a noise source that fades in gradually before the compressor comes on and fades out slowly after the compressor turns off. This will minimize the annoying, sudden transition of sound.
lewando, Nov 27 2003

       I have a weird ability to tell when a compressor motor is about to cycle off. I'll be doing normal things and ignoring the sound of the refrigeration, then my attention will be drawn to the sound of the compressor, then 5 seconds later it will shut off. I've had this since I worked at a pizza place in 2001. Does a refrigerator motor change the sound before it shuts off? Certainly science has an explanation as to why I can predict when it will shut off.
Amishman35, Jul 29 2006

       Hey look! It's a plane! It's a bird! No, it's Precognitive Refrigerator Compressor On/Off Person!   

       My hero!
NotTheSharpestSpoon, Jul 29 2006


back: main index
