L.G. Refrigerator

54d18 said:

I've posted before asking about fridges, I ran into this as a possibility,
just looking for any opinions or comments about it, says it's Inverter?

https://www.costco.ca/lg-24-in.-11-cu.ft--platinum-silver-counter-depth-top-mount-refrigerator-with-smart-diagnosis.product.100462755.html

Thanks,

T

I understand this. We are off grid as I suppose your cabin is as well. But what is your power? Solar? System voltage and inverter size? Or is it generator with the fridge on when the generator is running ?

This year we had to replace a 12 year old Maytag 21' Energy Star. It had been a great fridge but when it went warm we couldn't mess around so we bought a Samsung 21', also EnergyStar rated. Your reference to an inverter fridge intrigued me. I can understand the ramping up and down, surge draw, etc. But both our old Maytag w/ice and the new Samsung w/ice (not that the ice matters except for overall draw) are minimal for inrush. With the Kill-a-watt, the new Samsung is 37.7 watts per hour after stabilized. The old Maytag was a bit higher draw per hour on average but not so much.

A biggie to me is service. We couldn't get anyone to show up fix the Maytag. In turned out to just be the freezer to fridge circulating fan which is common. There is still a problem with the thermostat. And I had to add a squirt of coolant. I just don't want to spend another $150 part on it as its now a backup deck fridge. This is a different conversation.

So I guess I need some education. Yes, power factor is an issue but on a newer Energy Star appliances in good working order? The draws are so very low? We have the two fridges, two Maytag Energy Star chest freezers, LG DC direct drive washer (granted, once/week for multiple cycles) and many of the things that city dwellers hold important with the obvious exceptions. And the inrush is almost not worth noting on any of these on the ES stuff.

Please explain.

I woke up last night thinking of this PF conversation. Duh, yeah, this stuff stays with me. I had to look it up again. My memory fades faster than it used to and I needed a refresher: Here is a good layman's description and go to the example:

https://laurenselectric.com/home/business/understanding-power-factor/

This one of the best layman term descriptions I have read. And this is key: "A steel stamping operation runs at 100 kW (Working Power) and the Apparent Power meter records 125 kVA. To find the PF, divide 100 kW by 125 kVA to yield a PF of 80%. This means that only 80% of the incoming current does useful work and 20% is wasted through heating up the conductors."

What does this mean to an off grid user? Yeah, a lot of AC motors suck for efficiency. The water well, the shop equipment, the vacuum cleaner (with other loads), etc.. We already know those precautions. But still, if the system is sized correctly and you are using loads when and where best, who gives a flip? It matters not to your inverter as long as it was sized correctly. The bottom line to me is to minimize inrush. We have a 3600 watt inverter. Almost never has it kicked out unless on generator power and then to bypass, falling back to the inverter solely. And that was the lack of the generator and the surge load. Once that surge is done it does back to the generator feed through. A fraction of a minute.

Of course we want to get the best "bang-for-the-buck" and minimize hitting electrical stuff with a sledgehammer, but to what end? To me it is heat. If an electric motor heats it is waste. If the batteries heat it is waste. As components heat it is waste. If wires heat it is not only designed poorly but dangerous.

So getting wound up about the PF of a refrigerator/freezer is silly, but always use an Energy Star evice. Water well, ah, that's a biggy.** Of course the better PF the better. But paying bazzillions of $ for the absolutely lowest PF device is a return you might not realize - unless you are running your system right up against its top capabilities.

**As for a water well pump, I was fortunate to go with a Grundfos SQF AC/DC. It slow starts with whatever it gets but it was pricey then. But 15 years later it hasn't missed a beat and doesn't care the source, AC or DC. Considering what I saved not building a bigger system to handle inrush from just the well, our biggest potential load, it has paid back multiples. And since the original plan I don't have a separate solar input for just the well cause the 48v batteries expired. I plug it into the house 120vac system with a 16ga cord. 800 watts. The difference is minimal unless a hose bursts.

"20% is wasted through heating up the conductors."

That should read 20% more actual losses if the power factor was perfect.  So, if resistance loss was 5W, it will be 6W with 80%. Nothing to lose sleep over. With inverter fridges all the current is at the peak making it look more like a MSW inverter. Inverter doesn't care it just draws more power at the peaks.