this post was submitted on 19 Oct 2024
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[–] sxan@midwest.social 44 points 2 weeks ago (3 children)

So, I learned something interesting about the technology underpinning refrigerators once. In my case, it was an old HVAC AC unit.

We had it checked once, and the tech said the until was really old, but seemed fine. It turns out the old units lasted forever, because they were made with heavy duty materials - thick steel, etc. The downside was that the efficiencies were really low. He said it was a trade-off: you get higher efficiencies by using thinner metal with better thermal conductivity, but you sacrifice durability. Basically, it's a trade-off between durability and efficiency. Whatever built-in obsolescence you get is on top of an essential limitation in physics: it takes more energy to transfer heat between thick metal and thin, and thin just doesn't last as long.

I'm not a materials scientist, so I'm probably paraphrasing him wrong and misinterpreting it, but since his advice was to not replace it until it died, which could be another decade, unless I had an urgent desire to get a higher efficiency unit, I figured he wasn't BSing me and took him at his word.

I absolutely believe in planned obsolescence, but I also believe that there are some fundamental laws of physics contributing to lifespan of appliances. If you want high efficiency (in some types of appliances, such as refrigerators), you're generally going to be working with more flimsy materials which are more prone to breaking down.

I suspect that the higher efficiency don't make up for the irreparability and subsequent waste of replacing appliances more often, but Energy Star contributed to requiring some of that, so not all of the blame can be laid on manufacturers.

[–] Vodulas@beehaw.org 29 points 2 weeks ago (1 children)

I dunno if that is true of refrigerators. Newer fridges have more electronic components, vs just a compressor and some simple mechanics on older fridges. The cooling tech on fridges hasn't changed much, but the extra amenities sure have.

[–] BearOfaTime@lemm.ee 17 points 2 weeks ago (1 children)

Yea, for appliance components like compressors, thinner materials has practically no impact on performance (but probably saves a little money on manufacturing, and probably reduces life span).

For the condenser and evaporator, it could make a difference, but those have been largely optimized probably since the 60's - they're not complex things. Even there, a thinner wall on the tubing isn't really going to make a major improvement, since it's fin density that really matters.

It's controls that break 98%+ of the time. A refrigeration circuit is pretty simple, so long as you don't poke a hole in the system, generally it will continue to work.

Of all the systems I've worked on, I've rarely replaced even a compressor (it does happen). Condensers and evaporators practically never wear out - almost all that I've replaced have failed from being hit by something, or being cleaned with an unfriendly chemical (some newer ones are really fragile, and even conventional ones don't like dog urine on them constantly). A family friend has been an HVAC guy since I was little (he taught me), and this squares with his experience.

Controls are #1, seals are second (especially on automotive systems, since they get shaken around constantly and deal with much greater temp swings).

"New" stuff (starting in the 80's) has shit electronic controls - they're manufactured as cheaply as possible (unlike say electronic controls for a car engine or safety systems, which have to meet regulatory requirements). Old school controls are so simple there's little to go wrong.

The "new" DC/inverter compressors are probably the biggest improvement in recent years, since they can run at varying loads instead of just off/on - this should make them noticeably more energy efficient.

[–] Vodulas@beehaw.org 7 points 2 weeks ago

I know some recent Samsung fridges had issues with compressors getting frost build up on the outside causing damage. Wonder if that is a result of thinner/cheaper materials.

[–] colournoun@beehaw.org 10 points 2 weeks ago (1 children)

The pieces of refrigerators that have failed me in the last 15 years have been the plastic parts. A small improvement in plastic quality or engineering seems like it could double the life of the refrigerator. And of course a small plastic replacement part costs $50 or more.

[–] sxan@midwest.social 2 points 2 weeks ago

My last fridge, something in the compressor failed; it would have cost almost as to fix as replace.

But maybe fridges aren't the same as AC units and heat exchangers. If I knew that, I could probably have fixed my fridge myself :-/

[–] ProdigalFrog@slrpnk.net 7 points 2 weeks ago

In the case of refrigerators, there doesn't need to be any trade-off between efficiency and heavy duty. The main thing determining efficiency is primarily where the heat exchanger is positioned (top mounted is the most efficient, but uncommon), and the thickness and quality (R value) of the insulation.

If you add extra insulation to an old heavy duty fridge, it increases its efficiency by 50% or more (depending on the thickness of insulation).

The extra insulation, as a side effect of better efficiency through better temperature retention, will also extend the lifespan of the compressor, which will need to run half as much as normal.

The main reason this isn't done from the factory is cost, and to reduce the physical dimensions of the fridge.

[–] johny@feddit.org 22 points 2 weeks ago (1 children)
[–] ProdigalFrog@slrpnk.net 9 points 2 weeks ago (1 children)

Yes, but can be reduced by half with extra insulation :D

[–] ninjaphysics@beehaw.org 2 points 2 weeks ago

Excellent rabbit hole of posts! Thank you, friend!

[–] elucubra@sopuli.xyz 8 points 2 weeks ago (1 children)

Modern heat pumps, which use the same principle as A/C, can achieve 4 to 1 efficiency. Old fridges can be tanks, but are horribly inefficient. A new high efficiency unit could probably pay itself off in 2 3 years.

[–] Vivendi@lemmy.zip 2 points 2 weeks ago (1 children)

If you're extra brave and handy with hardware hacking you can replace the internals with new tech

[–] elucubra@sopuli.xyz 1 points 2 weeks ago

True, but with the insulation upgrade you'd basically end up with a DIY fridge that will probaby cost more, work less well and fail sooner.

[–] No_Eponym@lemmy.ca 4 points 2 weeks ago

Don't look away. RIP Phillip.