[Greenbuilding] [BULK] Re: Refrigerators

[Reuben Deumling]

Very effective.
Yes. Before in an unheated kitchen the fridge consumed 182 kWh/yr (2000)
In 2001, in same kitchen the fridge consumed 122 kWh/yr. Then after some
more tinkering (2002) I got it down to 98 kWh/yr. The label suggested it
would consume 413 kWh/yr in the standardized test: 90F with no door
openings. The fact that this was in a North facing kitchen in Berkeley, CA
helped considerably. We moved the same setup to Portland, OR and the fridge
which had used 98 kWh/yr now consumes 135 KWh/yr. The difference is due to
an increase in average interior (kitchen) temperature and perhaps a small
amount to aging of the compressor and refrigerant loop.

As for the insulation, we added 3-1/2" of rigid foam, gently prying the
coils away from the rear enough to fit the insulation sheet between them and
the back wall. I taped up the open faces with aluminum tape so the whole
exterior surface now has the dull sheen of aluminum foil that isn't
stretched taught. I didn't insulate the door or the floor at the time, but I
did insert a sheet of styrofoam in between the freezer compartment and the
fridge (this is a single door, remember). This amazingly made almost as much
difference in the energy performance as the whole exterior business.  Older
single door manual defrost fridges, such as we all had once upon a time,
were designed with much more intelligent baffles and some insulation between
freezer and fridge compartments, but these days, regrettably, these smaller
fridges are not something manufacturers spend much R&D on.

I would not maintain that the fridge is beautiful, and it certainly is
larger than before, but in practice one only really sees one side that is
insulated. To insulate the doors I will need to machine some new door hinges
and I'll probably have to glue or screw the insulation to the box, something
I have so far avoided since when I began I was not sure it would 'work.'

The whole insulation project took about a day. I'd like to figure out a way
to gently move the compressor from its location beneath the fridge to a spot
some inches further back, in anticipation of putting the fridge's coils
through the wall of my North-facing kitchen), and the next round of
improvements. The other alternative would involve paying someone a bunch of
money to suck the refrigerant out, swap out the existing compressor for a
slightly more efficient one (Sanyo's 2001 compliant model), and resolder the
new one in place with a bit of extra tubing. I'm reluctant to do this
because I have no way to ensure that the charge will be as well matched to
the loop length as it is now... Any thoughts?

Reuben Deumling


On Nov 12, 2007 3:24 PM, Lawrence Lile <LLile at projsolco.com> wrote:

> I'm curious about this tinkering business.  How effective did you think
> it was, Reuben?  Did you get a before and after metering snapshot of it?
> At some point, does opening the door use more energy than exits through
> the insulation at idle? What did you cover the foam with?
>
> Lawrence Lile, PE, LEED AP
> Project Solutions Engineering
>
> -----Original Message-----
> From: greenbuilding-bounces at listserv.repp.org
> [mailto:greenbuilding-bounces at listserv.repp.org] On Behalf Of Reuben
> Deumling
> Sent: Saturday, November 10, 2007 1:56 PM
> To: Bob Korves
> Cc: greenbuilding at listserv.repp.org
> Subject: [BULK] Re: [Greenbuilding] Refrigerators
> Importance: Low
>
> I think the idea behind SunFrost fridges is really good. But you can
> find
> fridges by Avanti, Sanyo, Danby, GE, Kenmore, etc. in the 8-12 cf range
> which don't use much electricity, and they cost about 1/5 of the
> Sunfrosts.
> By not much electricity I mean between, say, 200 and 320 kWh/yr. Then,
> if
> you tinker a bit with these, you can probably get one of these to use
> even
> less. The 9.5 cf Sanyo fridge, which I bought ten years ago and have in
> my
> kitchen, consumes about 135 kWh/yr these days. It cost $350 and the
> rigid
> foam insulation I added to it about 7 yrs ago cost about $40.
>