Date: Thu, 13 Sep 2012 11:26:10 -0700
Reply-To: neil n <musomuso@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: neil n <musomuso@GMAIL.COM>
Subject: Re: Danfoss VS Sawafuji Compressor. Which is Electrically More
Efficient?
In-Reply-To: <1347552683.78495.YahooMailNeo@web163405.mail.gq1.yahoo.com>
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On Thu, Sep 13, 2012 at 9:11 AM, Poppie Jagersand
<poppie.jagersand@yahoo.ca> wrote:
>
>
> ________________________________
> From: neil n <musomuso@GMAIL.COM>
> To: vanagon@GERRY.VANAGON.COM
> Sent: Wednesday, September 12, 2012 10:01:22 PM
> Subject: Danfoss VS Sawafuji Compressor. Which is Electrically More
> Efficient?
>> If a Sawafuji and Danfoss powered fridge were wired to be manually
>> switched on/off at 15 minute intervals, (bypass thermostat) and each
>> had the same test conditions, which fridge would consume less amps in
>> an hour?
>
> MJ: I think you forget that the temp in each fridge will not be the same
> just because the compressor is run the same amount.
My thought was to "bypass" comparing cooling capacity of each same or
similar sized fridge.
My highly unscientific attempt at a simplified test method was to look
only at each motor + compressor parts and what they drew when operated
manually under the same conditions.
I've read some of the tests done in the manner you speak of. There's
conflicting reports. I'd really like to find test results from a
controlled, unbiased tester. Maybe I need to renew my Consumer Reports
membership. ;^)
> The relevant comparison would be to put similar size chest models next to
> each other. Set thermostat and verify that they keep a particular inside
> temp (e.g. 4C). Then measure AH consumed by each over a typical day (or week
> for better accuracy). Put some jugs of water inside each for a realistic
> thermal mass.
I agree totally. And maybe that's what makes my simpler test moot.
Real life use would dictate the efficiency of the total package. Even
IF the Sawafuji + its' compressor parts were more efficient by
themselves, how well does the fridge in its' entirety do?
>> It seems that in terms of current draw to "power up" either of these
>> compressors, the Sawafuji may have the advantage.
> I think not. Startup current spike is so brief that it does not affect
> average Ah consumed. There's also no compelling scientific reason one
> compressor type would be inherently more efficient than the other.
Ok, interesting. Some say that at start up, the Sawafuji draws less
current. IF true, I thought that in high ambient heat, fridge cycling
on/off a lot, the Danfoss current spikes would significantly increase
total amps used. OTOH, the Danfoss motor and compressor parts do look
small. Based on that, I can "see" that the current spike might not be
that much.
I'm hair splitting. Which fridge type I choose may simply come down to
which type is quieter.
Neil.
--
Neil n
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