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Kopites_Roar t1_j28b61j wrote

It's such a good improvement and so obvious in hindsight - that's what makes you wonder why it's not always been done this way.

The only question is whether the vacuum will leak through the plastic over the years and if it can be "revacuumed" to maintain it. If that's an expensive process (I'd prefer some sort of schrader valve to DIY it).

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Warpzit t1_j28dzdu wrote

You don't need complete vacuum so it should be possible to reapply after repairs but I suspect we will see repeat of current solution which is replace...

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Riegel_Haribo t1_j28i2c1 wrote

The first refrigerators are only getting this in the door.

What typically degrades vacuum is outgassing. They've ground up some rocks (and claim that prior insulation is petroleum foam instead of fiberglass which is also environmental), but if not an engineered material, it may have volatiles that continue to be released.

Vacuum can be renewed, but pulling quality vacuum takes time (after a certain point, you are waiting for molecules to wander out of the vacuum port) and dewar-quality needs multi-stage pumping with consumables like pure oil and liquid nitrogen.

The rock/pumice, etc is likely a material to prevent the layers from collapsing onto themselves from pressure. However, that is also what is called a thermal short.

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Thercon_Jair t1_j2aaptf wrote

Probably because foam is cheap and was good enough with cheap electricity and no pressure to reduce electricity use.

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dillrepair t1_j2a5he5 wrote

Because manufacturing cost is probably a bit higher, and mfrs mostly don’t really care whether we use a bunch of energy or whatever they want to sell lots of appliances at a higher profit margin

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tropic420 t1_j2bojdy wrote

It's literally cheaper to pull a partial vacuum on the fridge every time you open the door. Which my 10 year old side by side unit does.

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GryphonHall t1_j2bsryk wrote

It’s obvious, which means the obvious reason is cost. Vacuum panels have been used in refrigerators before, but it’s been cheaper to make refrigerators thicker than add vacuums inside the structure to meet governmental energy requirements. Compressor improvements and foam are going to start struggling to meet ever tightening requirements, so vacuum panels and structures could be a new measure to meet guidelines.

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