Subject: refrigerator ideas

From: [email-masked] (Tom Leone)
Date: 16 Jun 1994 14:48:10 GMT

Here is a summary of the 15 or so replies I have received on the topic of
improving refrigerator efficiency by taking advantage of cold winter
weather (many thanks to all who replied).

1) Refrigerators designed for residential use will not operate properly at
very low temperatures, so my idea of putting the coil outside won't work:

> Your refrigerator would not work in the cold weather. This is because 
> the condenser temperature is so low that there is insufficient pressure 
> in the liquid refrigerant to drive it across the expanison valve. The term 
> is "low head pressure." However, you can design around this.
(thanks to Kevin Chisholm, [email-masked])

2) Many people suggested using the waste heat to pre-heat water for the
water heater.  Another variation suggested was running all the house's
water past the coils, so they would effectively be rejecting heat to a
lower temperature.

3) The refrigeratore is not a major electricity user (thanks to
[email-masked]):

  From Mother Earth News, April/May 94 issure:
        heating of space        57.5%
        water heating           14.9%
        refrigeration            6.0%
        cooking                  5.5%
        air conditioning         3.7%
        lighting                 3.7%
        television               3.0%
        food freezer             1.9%
        clothes dryer            1.7%
        others                   2.3%

4) A couple of people suggested a variation on the "icebox" idea, where
ice would be stored year-round in an insulated pit, and a circulating
fluid would keep the frig cold.

In summary, it looks like the frig is not a major electricity user, plus
taking advantage of cold weather would be difficult.  So the best route to
conservation is sensible usage and maintenance (thanks to John
MacConnachie): minimize the number of times you open the door to the frig,
keep the coils clean, and check that the door seals are airtight.

Also, the newer refrigerators are much more efficient than older ones, so
it may be worthwhile to investigate payback times for a new purchase.  One
reply quoted 700 kWh/year for a new frig vs 1200-1300 kWh/year for current
in-use average; another quoted 324 kWh/year for a miniature Sears frig.

Tom Leone <[email-masked]>