Date: Thu, 13 Sep 2012 20:47:00 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: Danfoss VS Sawafuji Compressor. Which is Electrically More
Efficient?
In-Reply-To: <CAB2RwfiJ3S-UAiGLEriobK5iR2OZEawKyALq2XaDGoL+Q2_NOg@mail.gmail.com>
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Both of these fridges use a similar technology. If there is an overall
difference I doubt it is much greater than a few up to 10%. So does 48 hours
or 50 hours difference really an issue? Your usage requirements (how long is
it needed before driving), and how much battery or other power you are
willing to carry will dictate if this is a reasonable solution. Both units
will do a great job.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
neil n
Sent: Thursday, September 13, 2012 2:26 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Danfoss VS Sawafuji Compressor. Which is Electrically More
Efficient?
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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