New smaller Isotherm Compressor ?

OffLeash

Hi all
We have been thinking about supplementing the standard c-dory Refrigerator/Freezer with a separate small portable unit to make ice and keep some frozen food available on long trips. I have been concerned about adding the power needs of another compressor. It appears most portable Refrigerator/ freezers use the same compressor as the current unit in the boat so we would basically be doubling the power needs...(I think)

Yesterday a salesman at our local marine supply showed us a .64cubic foot Isotherm 18 that has a new Micro 1.4F compressor vs the standard heavy 35 compressor most companies but Engle use. It is significantly lighter and it is supposed to be much more efficient but I really cannot find or understand if this compressor is significantly more efficient.

Anyone have any experience or knowledge with this smaller compressor and its power use?
I am kind of in a hurry because Defender has a really good price on sale right now.
Thanks.
m

BrentB · Posted: Sun Sep 18, 2016 7:17 pm Post subject:

I dont have but here is the data sheet
Looks well done

http://www.secop.com/solutions/bd14f-vsd/technical-data.html

The new BD1.4F-VSD from Secop is 60% smaller than previous models and weighs in at only 2.3 kilograms. Perfect for 10-30 litre in-car/van/boat cabinets or portable boxes that need to fit into tight spaces without compromising storage space.

Specially designed for maximum efficiency and reliability this powerhouse of a compressor makes it easier than ever to provide leading class mobile fridges.
Enabling the variable speed function increases the system’s COP. Low energy consumption is beneficial for car/van/boat batteries – as well as the environment.

The optimized, low noise motor ensures outstanding performance when you want to provide that extra degree of luxury on the move.
The electronic thermostat (NTC sensor support) provides an accurate temperature while the failure detection allows a prompt fault diagnosis. The computer interface makes it easier for customization via TOOL4COOL®.

software
http://www.secop.com/fileadmin/user_data/pdfs/tool4cool/tool4cool_operating_instructions_01-2012_dess300e102.pdf

journey on · Posted: Sun Sep 18, 2016 8:33 pm Post subject:

From the spec sheet they're lighter, fewer parts and smaller. All good things, but no electrical consumption that i could find. If you're running off batteries that's the most important number, as you know.

The refrigerator we have in Journey On takes 6 amps and a 50% duty cycle. That's 3 amp-hrs/hr or an average of ~40 watts/hr. That's both the heat loss from the refrig as well as the compressor efficiency. If the ambient temp is high, one uses more energy.

I would hope that new designs are more efficient. That includes the overall unit and the compressor. I would want to see the power usage before I would buy it.

Boris

thataway · Posted: Mon Sep 19, 2016 12:00 am Post subject:

I have no experience with this unit, but the Data sheet, shows watts and amps for various conditions.

A lot depends on insulation. Does this small unit switch over automatically to AC?The specs only show 12 volts. As a freezer, the Defender ad, says 600 watts per 24 hours as a freezer. That means 50 amps per 24 hours-(assuming 12 volts--and many of these are really rated at 13.7 volts, or the car alternator/battery voltage when running)-not much better than my Dometic which uses the standard Danfoss compressor, and is over a cubic foot... (Danfoss is the compressor that most use). Part of the equation is insulation, or heat loss/gain thru the surface of the compartment. For a freezer, you want a lot of insulation. How is the heat generated by the compressor dissipated?

Sunbeam · Posted: Mon Sep 19, 2016 1:44 am Post subject:

This could be interesting. Thanks for posting about it.

Both of my small compressor refrigerators (one is 1.7 cu. feet and the other is 4.7 cu. feet) use the Danfoss BD35 compressor. A friend has a 1.4 cu. foot version and his also uses the BD35. (My) logic then says that a smaller compressor might make sense for the smaller refrigerators (say 2 cu. feet or less). 30 liters is about 1 cu. foot.

No complaints on my units with the BD35, but I sure wouldn't mind if the 1.7 cu. foot one (50 liters) was lighter. And I'm not sure they "need" the BD35. So I'm interested in this new possibility for future reference.

I don't know the exact ins and outs, but I think Danfoss and Secop are now basically the same company.

journey on · Posted: Mon Sep 19, 2016 11:20 am Post subject:

Well, Bob, I can't make sense of their charts on the spec sheet. Maybe another C-Brat can make it clear. However, for the number you quote, 900 watt-hrs, the average amperage @ 12.5 volts is 3 amps. Not an improvement over the refrigerator the factory installs.

Note that your figure of 900 must be in watt-hrs (energy) as opposed to watts (power).

Boris

OffLeash · Posted: Mon Sep 19, 2016 5:07 pm Post subject:

Interesting stuff on this...

Lighter
I can tell you it is significantly lighter than the dometic 18liter unit. I lifted both and the total weight of 20lbs on it is really nice...off course it was not filled with my favorite beverages. One other thing that looked good to me was that it had a lot of molded non rusting parts. I have a feeling that a little better insulation would help reduce the power needs.

Power consumption seems similar

The listing of 600watts for 24 hrs in freezer mode bothered me as well since it appears to be 50ah per day which seems about the same as the larger units and compressor. From the little I learned about these kind of technologies over the past few days, the computerized controller sounds like it would be more efficient on the surface of things but the numbers don't seem to make a big difference. It seems hard to compare apples to apples

Aurelia · Posted: Mon Sep 19, 2016 6:49 pm Post subject:

We have no experience with the Isotherm although it looks nice, but if you need any related info on the similarly sized and priced Engle MD-14, we have a season of use on that.

I have posted many of our experiences here.

http://www.c-brats.com/viewtopic.php?t=22215&postdays=0&postorder=asc&start=45

Pics here

http://www.c-brats.com/modules.php?set_albumName=album2425&op=modload&name=gallery&file=index&include=view_album.php

Based on wattage use specs, the Engle is 27w and the Isotherm is 35w of consumption. We went as small as possible for ice making only.

Greg