Okay, so the author proposes that the thermal losses from the cold air being replaced with ambient air make up for the hundreds of extra kWh/year consumed by a vertical fridge.
While chest freezers typically have better thermal insulation and larger evaporators than fridges...
So shouldn't we be comparing a chest fridge to a vertical fridge with a comparable insulation system and condenser/evaporator capacity before declaring that lower air losses are the reason chest fridges work better?
Air has a heat capacity of approximately 1 kJ/(kg K). Its density is 1.2 kg/m^3.
I don't know how big the fridge is, but someone elsethread said 600 litres, so I'll use that. (And assume that it's empty.) That's 0.6 m^3, and so has a mass of ~700 grams. Assuming ambient air temperature of 20°C and a fridge temperature of 4°C, that's a temperature delta of 16 K. Therefore the energy required to chill that air is 0.6 * 16 = ~10 kJ.
10 kJ is 0.003 kWh. Electricity costs about 20 US cents per kWh. Assuming a factor of ten fudge factor for cooling efficiency, then we can be reasonably confident that opening and closing the fridge would cost less than 0.03 * 0.20 = 0.006 dollars = 0.6 cents.
That's not a lot.
Does anyone have any figures on how good fridge insulation is, for comparison?
The two important variables are thermal mass and insulation.
The relevant comparison is how much heat escapes through the walls of the fridge relative to the heat loss via escaping air. Since fridge insulation has improved massively in the last decade that might actually be a significant share. The paper also mentions that an imperfect seal (due to imperfect closing or plain wear) on a vertical door leads to a constant trickle loss, while it does have much less of an effect on a chest freezer.
It's really not. I'd wager that the vast majority of the efficiency is due to the lack of condensation control rather than the fact it's in a chest orientation.
Pretty sure you couldn't easily get a chest fridge back then. I know, I looked for one a few years later.
The reason no one wants a "chest freezer" style fridge (which the author of the article advocates) is because it's a pain the back to get stuff in and out, not to mention organizing your food.
Yes, this is great for home-brewing. But nobody should kid themselves that regular people would want this to replace their "normal" upright fridges.
My guess for why traditional upright fridges could be seen as more convenient is because they take up less floor space for the amount of volume they provide. Also, upright fridges would be easier for small/short children to access. If floor space is less of a concern, and there is no need for small children to access the fridge, a chest-freezer-style fridge sounds like a brilliant idea. Next time I need a new fridge, I will seriously consider this as an option. Perhaps by then some contrarian manufacturers will realize how much sense this makes and I won't even need to convert a freezer myself.
Most of the stuff people use frequently ends up on the top shelves or in the doors of fridges. Lots of fridges have really deep door shelves to maximize this utility. Similarly, nicer fridge/freezer combos have mostly moved the freezer to the bottom to increase the convenience of the fridge.
Most fridges also have quite a few shelves so that you can get out the thing you want without moving everything. In a chest freezer, the baskets don't hold most of the food. Most of it is stacked on the bottom. So to get the thing you want, you inevitably have to move other things off of it. Refrigerators minimize this hassle.
Plus the condensation is gross and extremely inconvenient to clean when the fridge is full. I can't imagine leaving the walls of my fridge wet for 2-3 months at a time. You can address that with a chest fridge that operates like a normal fridge (cooling and therefore dehumidifying the air directly), but I bet you lose most of the efficiency gains as soon as you do.
[1] http://www.homebrewtalk.com/showthread.php?t=249612 [2] https://www.amazon.com/Johnson-Controls-A19AAT-2C-Temperatur...
as seen in the authors head shot at the end of the pdf.
that's no mere dead head tie dye you're seeing folks
"This article describes a household refrigerator that requires about 0.1 kWh per day to operate. The refrigerator offers excellent food-preserving performance, because temperature fluctuations in its interior are naturally minimized during everyday use. This fridge is 10 to 20 times more energy efficient than typical household fridges on the market today. It seems that the biggest obstacles in increasing the energy efficiency and food- preserving performance of household refrigerators are strange human habits and lack of understanding of Nature, not technology or cost."
http://webcache.googleusercontent.com/search?q=cache:_wPrLjU...
Missing the diagrams of the circuits but totally readable.
TL;DR; How
Have zero knowledge about anything.
Buy part on eBay.
Spend 5 mins double checking what to do. Spend 30 seconds replacing part.
Because this is done by a lot of homebrewers, easy and lots of info out there.
TL;DR; Why, if not for homebrew.
Because a fridge will lose a lot of air when opening. 600 liters of air weights 600 grams. This ~ needs to be re-chilled on each opening.
