EcoRenovator - View Single Post - How cold should a refrigerator/freezer be?

AC_Hacker · 09-04-12, 02:45 PM

I think that refrigerator design should be seriously reconsidered.

Start with size... If your refrigerator regularly contains spoiled food, it's not because you are running it at too low a temperature, it's because your refrigerator is just too big.

Then there is the Saga of the Decline of Good Refrigerator Design. Things began to go downhill when the compressor was moved from the most energy efficient location (Top, where heat could move away from the food) to the least energy efficient location (Bottom, where heat flowed around the food), and things have continued their decline ever since.

Insulation was made as thin as possible to allow for more room inside.

Then the condenser coils that were first on the top, were moved to the back where they were in closer proximity to the food, and the final brain storm was to put the condenser coils inside the sheet metal body where they are in contact with the insulation, and surround the food. Each 'improvement' has led to lower efficiency. Why, you'd think that the power companies were paying the refrigerator companies to be stupid.

Then, the act of monthly defrosting was determined to be too burdensome, so heaters were put inside the refrigerator to periodically melt the frost, so not only do we have resistance heaters with their notoriously high current draw, we also have the extra refrigerator run time required to eliminate the heat that was generated by the defroster feature.

* * *

Some wonderful work has been done in converting chest type freezers into ultra high-efficiency refrigerators, by simply adding a separate thermostat that will accurately hold temperatures in the 35 to 40 degree F range.

Quite a few people have done this conversions, HERE is the most recent conversion I know of.

Mr. Dirty Boots reports that his yearly cost to run the converted freezer is $6.63 (calculated at a power cost of 0.11 $/kw-hr)... that's some serious EcoRenovating!

And all of this with a freezer that most likely has all of the design sins cited above. So Mr. Dirty Boots extremely good low energy mark could be improved still further...

It's well to note however, that this conversion will not need defrosting, because it will not frost, because there is sufficient chill plate area inside to supply cooling, that the temp does not need to go as low as 32F, so no defrosting and also longer vegetable life.

* * *

And then there is Sun Frost...

These admittedly expensive refrigerators & freezers are designed for folks who live off-grid and must bear the price of site generated electricity, which is usually much higher that grid power... so

Here is a photo of one that is currently on ebay:

Note that the compressor & condenser coils are on top, note the very thick insulation that is used. Also, not so obvious is that the large cooler plate for the refrig area does not get to the point where water vapor will freeze, which means no defrosting and it also means longer vegetable life.

We can do this!

Best,

-AC

09-04-12, 02:45 PM	#7
AC_Hacker Supreme EcoRenovator Join Date: Mar 2009 Location: Portland, OR Posts: 4,004 Thanks: 303 Thanked 723 Times in 534 Posts	The Road to Hell is Paved with Convenience Features... I think that refrigerator design should be seriously reconsidered. Start with size... If your refrigerator regularly contains spoiled food, it's not because you are running it at too low a temperature, it's because your refrigerator is just too big. Then there is the Saga of the Decline of Good Refrigerator Design. Things began to go downhill when the compressor was moved from the most energy efficient location (Top, where heat could move away from the food) to the least energy efficient location (Bottom, where heat flowed around the food), and things have continued their decline ever since. Insulation was made as thin as possible to allow for more room inside. Then the condenser coils that were first on the top, were moved to the back where they were in closer proximity to the food, and the final brain storm was to put the condenser coils inside the sheet metal body where they are in contact with the insulation, and surround the food. Each 'improvement' has led to lower efficiency. Why, you'd think that the power companies were paying the refrigerator companies to be stupid. Then, the act of monthly defrosting was determined to be too burdensome, so heaters were put inside the refrigerator to periodically melt the frost, so not only do we have resistance heaters with their notoriously high current draw, we also have the extra refrigerator run time required to eliminate the heat that was generated by the defroster feature. * * * Some wonderful work has been done in converting chest type freezers into ultra high-efficiency refrigerators, by simply adding a separate thermostat that will accurately hold temperatures in the 35 to 40 degree F range. Quite a few people have done this conversions, HERE is the most recent conversion I know of. Mr. Dirty Boots reports that his *yearly cost* to run the converted freezer is $6.63 (calculated at a power cost of 0.11 $/kw-hr)... that's some serious EcoRenovating! And all of this with a freezer that most likely has all of the design sins cited above. So Mr. Dirty Boots extremely good low energy mark could be improved still further... It's well to note however, that this conversion will not need defrosting, because it will not frost, because there is sufficient chill plate area inside to supply cooling, that the temp does not need to go as low as 32F, so no defrosting and also longer vegetable life. * * * And then there is Sun Frost... These admittedly expensive refrigerators & freezers are designed for folks who live off-grid and must bear the price of site generated electricity, which is usually much higher that grid power... so Here is a photo of one that is currently on ebay: Note that the compressor & condenser coils are on top, note the very thick insulation that is used. Also, not so obvious is that the large cooler plate for the refrig area does not get to the point where water vapor will freeze, which means no defrosting and it also means longer vegetable life. We can do this! Best, -AC Attached Images __________________ I'm not an HVAC technician. In fact, I'm barely even a hacker... Last edited by AC_Hacker; 09-04-12 at 02:47 PM..