Fighting Nature's Refrigerator

[VisualMonster]

A related article was just posted on www.treehugger.com

See here:  http://www.treehugger.com/files/2007/03/freeaire_refrig.php

[CmeBREW]

All very interesting ideas. I often have thought about placing a plastic 50 gal. drum outside one of my windows, and putting a bunch of pvc pipes vertically inside to let them all completely freeze with water inside---so that it is like one GIANT ICE CUBE. Then simply place an insulated box on top of it with open ports or holes into the 50 gal drum. --Then take my window out and make a simple air tight insulated door on hinges where the window use to be. That big of an ice cube might keep things cold until the middle of june! Hate to miss out on the light from the window though.   --good stuff!

[spinningmagnets]

Here's a thought. My wife wouldn't want to go outside to ponder what to defrost next, and neither would I. But you can easily convert a free discarded fridge into a freezer that is placed indoors, but out of site (garage, basement, etc) Take the compressor out and set aside, you'll just be using the free fridge as an insulated box. Set the fridge on its back with the long side against the wall, so the door lifts up like a laptop computer opening (with a pulley, cable and counterweight to make opening easier?)

When your outside night temperatures are consistently below freezing, clear out your kitchen freezer (if you don't open it, it shouldn't cycle very much) and put the food in the garage fridge. Put several jugs of water in with the food. Cut holes in the old top and bottom of the fridge (which are now its left and right sides) and run insulated dryer ducting from the fridge through the wall.

You can make a small "toy" VAWT to spin a shaft that turns a fan blade to pull in the night air through a screen. Salvage two bi-metallic springs from the intake air filters of a 60's/70's truck engine. During the 5 minutes it takes for an engine to warm up, the carb air is pulled from a duct that gets air from a sheetmetal shroud over the cast iron exhaust manifold, this warm air prevents the carb throat from icing up. After the engine is warm, the bi-metallic spring uncoils from the warmth, turning a shaft that rotates a butterfly and makes the carb suck cold air which is denser (more power).

It should be easy to "clock" the mounting so the coil shuts a disc in the duct opening when the temp rises to +32 degs. A "stop" can prevent the disc from rotating beyond shut no matter how warm it gets, and another stop can prevent it from rotating past 90 degs open no matter how cold it gets.

When you open a "top-opening" fridge, the cold stays inside instead of flowing out to cool your feet like in a common stand up model. During the day, the frozen water jugs should be adequate to keep the food very cold.

Fridges are real "Watt-hogs", and half the juice is used for the constantly cycling "auto-defrost" heater (the melted ice water runs down a tube drain to a floor pan to evaporate). There's gotta be a way to bypass this function until the kitchen freezer is heavily frosted, and then use it "just enough" to clear the frost once a week?

If you don't want forest air in the fridge (skunks, insects smaller than inlet screen holes, etc) you can cycle the outside air through a salvaged 18-wheeler turbo intercooler thats placed in the cold box, its an aluminum air-to-air heat exchanger.

The old fridge compressor doesn't put out much pressure but a useable amount of Hydrogen can be put into an old 100 gal propane tank, H2 acts like natural gas (C1H4) when burned (bar-b-que, room heater, water heater, etc) You can get H2 by putting excess amps into water.

BTW this is my first post here, this site is truly wonderful. I'm just an old truck driver, so please be kind when I occasionally pop my mouth clutch before I've engaged my brain gear. -Ron

[jeffbirkle]

I have done similar at my cabin.First get a fridge with  feon cooling tubes outside(on the back) and move the tubes and the compressor 6 more inchs away from fridge, (there should be enough room). Then put 4 inchs of pink styrofoam around entire fridge, including door, making sure door still opens.This alone will give extra efficiency.Then i cut a hole in the wall and mounted it so that just the door was inside (freed up some space too) Then i drilled and installed two holes 1.5" pvc tube with screens (one on the side at the bottom the other right at the top) and made two styrofoam plugs to fit the pvc snugly.So what i do is above zero run fridge and below zero turn fridge off and open plugs.works great and no fans required because warm air rises and draws cold air in the bottom.hope this helps.

Jeff

[zeusmorg]

 Years ago, i saw a design for a "super efficient" refrigerator. First, the refrigerator itself was super insulated, then the second major modification that was made was putting the condenser (those tubes normally located on the back) outside. Similar to an electric heat pump. The major advantage was keeping the hot air outside during the summer, and in the winter the system ran much less. My thought was if you had a refrigerator with back mounted coils, you could do a simpler modification by placing insulated panels top sides and bottom sealing between the refrigerator and the outside wall. Then have vents top and bottom with small 120v fans (computer fans are normally 12v)wired into your refrigerator circuit to turn on when the compressor was running.(Most refrigerators have a schematic on them) This would increase your efficiency dramatically over some of the schemes I've seen listed here, and be much cheaper to implement. Of course, you do have those holes through your walls. It could also be routed to a cold area, like an unfinished basement.

[martin1]

I've tried your idea with a vent in the refrigerator. I use two 2" plastic pipes with a small DC fan in one of them. The other pipe is just for circulation.

It works fine but I need to make one pipe longer for better circulation and it means that I have to cut holes in the glass shelfs. Maybe you guys know how to cut a 2" hole in safety glass?

[spinningmagnets]

It may be possible to grind a hole with a dremel tool and a stone bit.

[TheCasualTraveler]

     First of all I would like to say I admire anyone willing to cut holes in their fridge. Their confidence in their skills surpasses mine.

     Secondly I would like to make a few simple suggestions. If you live in a climate where freezing temps in the winter are the norm I would take several gallon or 2 liter plastic bottles, fill with water and set them outside the door to freeze. When they are solid bring them in and stick them in the fridge. Use as many as you have room for and rotate them as you come home and head right to the  fridge for a beer. With several solid lumps of ice in it your fridge it will act like a cooler and will run less. No construction, no expense, just savings. It does take a simple commitment to routine but what in conservation doesn't? And how much time might you spend on a more complicated solution? In Florida this wouldn't work but here if there is a Hurricane approaching we fill the freezer with water bottles to freeze and then spread them thru the fridge. We can keep food cold for days after an outage.

     If you have central heat I would try closing off the vent in the kitchen since the fridge already puts out heat your kitchen may be hotter than it needs to be. This may save on heat and help the fridge stay cool.

     The idea Countryboy mentioned is a good one. An outside box with a door to the inside. Maybe a box hung outside covering a kitchen window with an insulated door leading in?

     Isolating the coils in the back of the fridge and venting them outside in summer months is something I've been meaning to do and am ashamed I haven't since it would be so easy in my case. I promise I will do it before I turn on the AC next summer.

     And last, good old maintenance. Keep those door seals clean and fitting tight. Don't stand with the door open wondering what you want, (basically what Mom told you). And they say an empty fridge works harder than a full one. If you have lots of empty space, fill it with water bottles and such.

[domwild]

What is being sold here in Oz is conversion kit to use a freezer as a fridge. The electronic kit switches the compressor on/off. As a freezer is better insulated you save a few bucks. Disadvantage is the lack of horizontal shelfs. Advantage is that cold air does not fall out of a freezer when door is opened.