Ecomodding my fridge

[ecomodded]

Back from the used/unused Building supply store.
The foam i wanted was gone. I had seen a large amount of thick foam there last time i was in. Found nothing there that was priced right, they had new 2x8 blue rigid foam insulation for $22. Not what i was hoping for so i continued down the road.
Stopped in the Habitat for Humanity Re store, a store where they sell unused and used building supplies. Mostly left overs from builds. Found some insulation but i need more, I am going to keep looking and keeping an eye out for the 2" blue rigid insulation.

[ecomodded]

Cork works well for insulation, more so if have not a lot of space to apply it to.
Sailboat owners retrofit cork onto the inside hull walls for insulation, it comes thin on 3 to 4 ft wide rolls.
Cork flooring would work excellent, its about a inch think and can be found used/ previously installed.

[AllenK]

[QUOTE=Piwoslaw;324226]You mean like this?


Hehe, my self-insulated fridge does not look that wild and hairy. After glueing the styrofoam which did reduce power consumption down to a half of the original baseline i added some decorative foil (details and more pics here: Make your old fridge green by insulating it)

The result looks quite like a normal fridge i would say. But judge yourself. If you look closely you can see that the door and the side are insulated.

[jonr]

You got me motivated to check mine. The coils were thoroughly covered with dust - it took a vacuum and then compressed air to get them clean.

[Randy]

I used a chest freezer/thermostat as a refrigerator for a few years. It used about 15 watts in the summer and 11 in the winter on a continuous basis (about 100 watts when running). I think the main savings was condensation, as it quickly gets to 100% humidity. Another is that the expansion coils are at the fridge temp instead of freezer temp, which should lead to a higher coefficient of performance. The top-opening door doesn't hurt, obviously. For freezing I had a fairly big chest freezer running at around 40 watts average.

I switched to a normal fridge partly due to the disadvantages (space efficiency and condensation), and partly because fridges are quite efficient these days. My old fridge of early 80's vintage used a lot of power... about 200 watts continuous, and around 700 watts when on. The chest fridge paid for itself very quickly. The new one, which is a normal no-frost top-freezer from Lowe's (not a super-efficient Sunfrost) uses 101 watts when on, and 35 watts average. I don't know why they're so dramatically different, as it's very similar other than thick doors. Thermodynamics hasn't changed in the last 30 years, but fridges sure have!

I think the best plan is to start with a modern (post-2000) fridge. A chest fridge is extremely efficient, but adding another freezer cancels it out. Robert's 680 watt draw means an older fridge and likely huge savings just for buying a newer one. The run wattage is a big deal, even if run time is up. Note that chest freezers can't be further insulated because the condensation coils are on the outside, but fan-cooled fridges don't have that limit.

[Piwoslaw]

Originally Posted by Randy

I don't know why they're so dramatically different, as it's very similar other than thick doors. Thermodynamics hasn't changed in the last 30 years, but fridges sure have!

Around 2000 vacuum-packed insulation (or whatever it is called) went mainstream, resulting in a much better R-value from the same thickness. Add to that more efficient (and quieter) scroll-type compressors.

Originally Posted by Randy

Note that chest freezers can't be further insulated because the condensation coils are on the outside, but fan-cooled fridges don't have that limit.

They can - the coils are on 1 or 2 sides, which leaves 4-5 sides free to be insulated. Each side counts.

[ecomodded]

I have finished insulating my fridge, it was a success giving a 38% improvement in efficiency/energy consumption.
I also added a rear exhaust vent for the insulated compressor / condenser area to exhaust into a hall closet, instead of the kick panel.


I used 4 layers of 'SolidBlack' wood flooring insulation and one layer of blue vapor barrier over top along with 2 cans of 3M spray adhesive .
The under fridge is completely covered from kick panel and lower sides to the back of the fridge with a 4 layer sheet of SolidBlack. You can see it sticking out at the bottom of the fridge, that will be bent upwards and put in the top of the vent.

I am currently testing 10 gallons of water in 2 liter jugs in the bottom of the fridge.
I'll post back with the gains or losses from the PCM's (water jugs) when i collect more data.

[Frank Lee]

I just retired my 1968 model General Electric fridge- sad to see it go. They don't sell the new ones in Avocado Green. Ha- the old fridge was green after all!

Got a brand new FridgidAire of about the same size- 18 cu. ft. I happened to have a scrap piece of foil-faced foam (out of the same chunk I used to make the engine blanket for the F150) that was pretty much exactly the same width and depth as the top of the fridge, so up there it went. Perhaps someday the rest of it will get more insulation too- at least along the sides and back. Unfortunately the doors have a pronounced curve to them which although not impossible, complicates adding sheet insulation to the front.

Should see a nice power savings just from having the newer tech though.

[Christ]

I use a dorm fridge. Because I don't keep things in the fridge that don't need to be there, such as 2 week old left-overs and ketchup.

[darrylrobida]

Originally Posted by RobertSmalls

Ever since I read this article:

DIY, Super-Efficient Fridge Uses .1 kWh a Day | EcoRenovator.org

I've realised my 1KWh/day fridge is much less efficient than it should be. Unfortunately, the above super-efficient setup wouldn't work for me. I would need to find room for a second chest freezer for frozen foods.

The converted chest fridge is set to ~5°C, while I set mine to 1°C to keep wasted food to a minimum. His fridge in my house in the summer would use 0.2KWh/day due to the difference between our ambient and set temperatures. Add in a standalone freezer, and I'd be looking at around 0.6KWh/day. So my fridge/freezer isn't as hopeless as it appears. I need to find a 40% reduction in energy consumption to match his performance, not the 90% reduction that it looks like at first glance.

Door opening losses supposedly account for 7% of heat loss from a typical fridge, so switching from an upright to a chest fridge seems like a poor compromise between efficiency and convenience. I tried some window shrink wrap as a curtain to keep cold air in on the lowest shelf, but it's far too lightweight, crinkly, and annoying. It blows around every time you open the door. I bought a clear vinyl shower curtain at the dollar store, and I've hung it up to outgas and unwrinkle itself. Hopefully, it'll be ready to install next week.

The greatest room for improvement is insulation. Some folks say you can't insulate a fridge. But you can insulate the sides and top of any upright fridge, which accounts for half of its surface area. I currently have a sheet of 2" thick polystyrene insulation on top of my freezer. A thermal probe between the insulation and freezer confirms that it's holding heat in better now.

The back of my fridge has no vents or coils, and is cool to the touch. It sounds like insulating that is fair game, too.

I can't have bare insulation in the kitchen. Fiberglass presents a health concern, exposed polystyrene is a fire hazard in a room with so many ignition sources, and cotton would get filthy. I'd have to build a cabinet to mostly enclose the fridge, probably out of thin plywood. It would have to be built very precisely to keep air from infiltrating between the insulation and the fridge.

I suspected that since the compressor and condenser are on the bottom, heat enters through the bottom of the fridge compartment. A probe below the vegetables drawer under a kitchen towel reads 17°C (versus 10°C elsewhere in the fridge), and confirms that I need more insulation there.

I'd like to replace the fruit and vegetables drawers with fiberglass batting, but I'm not sure if it's okay to keep fiberglass in the fridge. Cotton batting (or corrugated kitchen towels) would be ideal, if only it was locally available and affordable. I've got an old wool blanket in there for now (the same one as my A/C seat cover is made from), but what if I spill some milk or beef juice in the fridge?

I'm open to suggestions. How can I keep insulation in the fridge clean? Does the insulation cabinet sound easy enough to build? Any thoughts on what to do with the door of the fridge?

I have tried several mods on my fridge. I wrapped the compressor with water cooling coils to carry the heat outside. I put a 1.5" layer of polystyrene
on the inside floor of both the fridge and freezer. Neither of these mods showed any improvement on my "Watts up" watt meter/data logger. The one thing that works for me is to clean the dust off of the condenser coils EVERY month. I have read that even a fine layer of dust reduces the efficiency of the condenser. My fridge is energy star, but I believe it is only energy star when it leaves the factory, And that energy star does not cover real world dust removal considerations. I hope this helps. My electrical bill is $14/mo.
While my fridge is a double wide/ice maker, chilled water in the door, and I have computers, a big screen tv, outside lighting. I'm grateful to have all the modern conveniences and a reasonable electrical bill. I have converted about half of my lighting to LED and eliminated all the vampire loads. My best electricity wasting finds are: My furnace standby ignitor was sucking 15W 24/7 for the 9 months that I never used it and my internet modem was using 17 Watts 24/7. It gets turned off automatically now when I shut down my computer.