Non Marine Fridge - 11 Watt

[Tellie]

Bingo!

[carstenb]

Anybody got a link on this "Engle" freezer/fridge? I'm trying to find a reasonable sized freezer to mount in my boat, but keep coming up against the very high power demands.

[Rivalman]

Here for example:

MPS for best prices on Engel fridges and Engel fridge accessories

[Fuss]

Originally Posted by Tellie

Even Engels top loading 84 quart or 2.8 cubic feet uses .7-3.6 amps at 12Volts or 8.4 to 43.2 Watts and the OP is talking practically twice the size at 4.6 cubic foot fridge or 137.6 quarts and it's probably a front loader he's looking at and my guess is on a 50 Cat that door will open a lot. Maybe myOcean will chime back in with the make and model of this fridge.

Here is an example of a front opening very large A+++ combined fridge freezer around 300 liters consuming 149000 watt hours per year.
35 hour storage period with the power off.

Fridge freezer Low frost

Of course its not really suitable for most boats but this example shows where the domestic technology is at the moment. Its all made possible with the use of vacuum panels.

149000 / 8760 = 17 watts on a continuous basis (just to be clear.. we are talking averages, not that it takes 17w all the time)
At 12 volts thats 34 ah per day
At 24 volts thats 17ah per day

Im not sure I have ever seen an off the shelf marine fridge with figures close to this.

The Engels dont seem to have 24 hour consumption figures.

The Waeco CR136 has an average of 65 watts... 1560w average for 24 hours.
The Waeco CR80 80 liter has an average of 48 watts... 1152w average for 24 hours.

At 12 volts thats 96 ah per day
At 24 volts thats 48 ah per day

[Dsanduril]

The Engels dont seem to have 24 hour consumption figures.

Partly that's because there are no standard test conditions. Anyone know what the standard test conditions are in the EU for that full-year energy rating? Has to be something that describes external and internal temperatures, air flows, etc. A fridge that uses 149kWh in freezing ambient conditions is not impressive, one that does when it is 35C on the outside of the fridge is impressive.

[Dsanduril]

Answered my own question, here are the basic test conditions for EU refrigeration:

Refrigerators’ energy consumption depends on a large number of factors. Besides of technical components like the cooling volume, the insulation, the compressor, the condenser and the evaporator, the way of handling it and the ambient conditions have a decisive influence. Especially the factors ambient temperature, internal temperature, frequency of door openings, degree of filling and placement of warm products are of particular importance.

Currently, the last mentioned factors are widely disregarded in European Energy Label test for domestic refrigerators. During this test, the fresh food compartment is empty, the doors remain closed and the ambient temperature is set at 25 °C. These conditions are artificial and seldom reflect the consumers’ real life behaviour and conditions. Accordingly, this is a frequent point of criticism.

Which means just as with cars and solar panels, YMMV.

[noelex 77]

The Australian test standards are at 35C, still with no door opening, but these are likely to be a bit more realistic if the model you are interested in is sold there.

Don't forget with these consumption figures you need to add the inverter consumption and inefficiency.Most inverters of a suitable size will have a self consumption of 0.5-1.0A and will loose another 5-10% in conversion.The inverter will need to be on 24hours a day. There are some inverters that will go into a sleep function if the off cycle is long enough, but you will need to choose carefully.

[motion30]

That is 11w ac? yes X 10 for dc

[noelex 77]

Watts are the same no matter what the voltage.

[s/v 'Faith']

Originally Posted by noelex 77

Watts are the same no matter what the voltage.

Yup... simple as PIE.

[Dsanduril]

Here are a couple of tables related to refrigerator testing. Oz is not included (sorry mates), but, as mentioned above, uses an ambient temperature of 35C. So, surprisingly does the US (actually 90F = 32.3C). In the US rationale this reflects that fridges are frequently installed in such a way that heat cannot get away from the compressor easily (cabinet installations, tight quarters, etc.). The exact same make/model fridge tested in the US or Australia will show double the annual energy usage to testing of the same fridge in Europe.

The other interesting thing to note is that for A++ (sorry, couldn't find results for A+++ so that we could do apples/apples) units the estimate of increased energy usage is about 40Wh/day/C ambient temperature change. That adds up pretty quickly.

[sailorchic34]

Originally Posted by noelex 77

Don't forget with these consumption figures you need to add the inverter consumption and inefficiency.Most inverters of a suitable size will have a self consumption of 0.5-1.0A and will loose another 5-10% in conversion.The inverter will need to be on 24hours a day. There are some inverters that will go into a sleep function if the off cycle is long enough, but you will need to choose carefully.

Exactly!!

I figured an extra amp due to inverter loss. So my usage at ~14.5 amps includes 1 amp for the inverter. Divide the 14.5 by duty cycle of 0.166 and its 2.41 amps per hour. Which works out to about 60 amps per 24 hours.

[Sumner]

Originally Posted by sailorchic34

Well its not quite 11 watts when it running. I've been using a 3.5 CF 120V fridge with a cheap modified sine wave inverter for over 5 years now here in the US.

Running it pulls 14-15 amps on 12V (1.3 amps at 110V). What makes it feasible is duty factor. It only runs for about 2.5 minutes every 14 minutes so about 2.5 amps used on average per hour (in the 90+ degree Cali Delta heat). So figure 60 to 70 amps a day. Which is in the ballpark of 12V systems....

If it is working for you and meeting your needs then there is nothing wrong with your fridge, but only poorly insulated 12 volt systems should be using that much a day.

Our EdgeStar 63 quart....



...portable uses about 30-40 a day in 80-90 degree cabin temps...

Macgregor 26S Inside Mods page 22

.... and the larger...



....4 cu. ft. with small freezer section fridge we made for the Endeavour is using...

Endeavour 37 Interion Mods Index

...about 1/2 of that (15-20 amp/hr a day).

Since the dorm type fridges are meant to be used with available AC they probably don't do much to them to make them super efficient.

The Endeavour came with a 12v/110v fridge that was a front opener, much like a dorm type fridge. It wasn't very well insulated at all. The previous owner day sailed and the boat was plugged into shore power most of the time so the fridge didn't have to run on 12 volts very much. The fridge worked well for him. We won't be plugged into shore power when we have the boat in the water so an efficient fridge was high on our priorities so we took the old one out and replace it with ...



..the new one.

If one doesn't want to make a fridge and feels that most of the portables are too expensive you might look at the EdgeStars. They are a true compressor type and we have been very happy with ours.

One just has to evaluate their needs and the dorm type fridges certainly have the edge when it comes to cost if you can handle the power side of the equation,

Sum

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[Thumbs Up]

You can buy a small a/c chest freezer (look for ones that say energy star). Wire a refrigerator thermostat into the power supply, and use it as a refrigerator. I am not sure what the numbers are and you won't have a freezer. Also some freezers don't like modified sine wave inverters.

[sailorchic34]

The edgestar is a 2 CF refrigerator or freezer that costs oh $560 ish. Really my fridge is 3.5 cf and includes a small freezer. The 3.5 CF fridge is 1.75 times the edgestar volume. Oddly enough factor in the increased volume and the energy usage is about the same per CF as the edgestar.

Agreed that a better insulated system would be more energy efficient. Alas I don't have the $1000-$1400 to insulate my icebox better and install a 12V compressor.

With solar panels being so much less expensive nowadays. It may sometimes be easier just adding another panel then to add 2-3 more inches of insulation to an already small icebox. I tend to be at anchor most of the time also.


Just offering a slightly different look at the issues.