Freezer Efficiency

[Paul Bailey]

Yes its a small and Ugly chest style freezer with an added 1 1/2 " rigid insulation. Hit a million times by the kids hockey pucks. Yet still saving me 1/3 the Kw > about $15 a year for the last 12 years for $15 bucks worth of foam, and a couple hours to install the foam as a test. Paul:)

[Ralph Day]

Hi Paul

I've often wondered about over insulating my freezer (new in '04) but the sides get quite warm. wouldn't holding that heat in be a problem? Anyone know how the modern freezer appliances dump the heat removed from contents with no free coils on the outside? I think it's through the exterior surfaces sheet metal, please correct me if i'm wrong. Somehow the latent heat from the contents, and the heat absorbed from the room must be extracted and exhausted.

For argument's sake, could a small fan blowing air accross the outside surfaces (removing that extracted heat) help reduce power consumption? You never know until you ask, or try!

ralph

[Paul Bailey]

Yes Ralph you are correct , you need to insulate the Cold sides and leave the Hot sides exposed to disipate the heat. This is why insulation Is always a Win-Win situation. You now have more R-value and the compressor runs less and therefore less heat to disipate as well...Paul:) Believe it or not i'm thinking of adding more for another Test!!

[Joe Blake]

Not sure if I've posted this previously, but it's a very interesting concept. Turning a chest freezer into a very effective fridge.

http://i82.photobucket.com/albums/j245/saxeharp/fridge01.jpg

http://i82.photobucket.com/albums/j245/saxeharp/fridge02.jpg

http://i82.photobucket.com/albums/j245/saxeharp/fridge03.jpg

I've tried to keep the image small enough for quick downloading, but you should still be able to read it. If you have trouble, let me know and I'll re-scan it at a higher quality.

My own approach is to use my solar powered 40 litre freezer (which draws a max of 30 watts) to freeze water and put into my "normal" 'fridge to help keep it cool, and lower the running costs.

Also using my water condenser's fan-driven exhaust, I have the outlet pointed at an angle behind my 'fridge, so that instead of just relying on thermal syphoning effect to take the heat away from the cooling coils, the exhaust generates turbulence over the coils, removing the heat more quickly. (Also remember the advice in the handbook and keep the cooling coils free of dust.)

Joe

[Stewart Corman]

Paul,
Can you relate to that article Joe posted that claims a chest freezer only used 0.1KW /day?? I don't believe it, not even if temp was raised to frig levels.

Yet still saving me 1/3 the Kw > about $15 a year for the last 12 years for $15 bucks worth of foam, you are implying that your total useage is only $30/yr?? or is your electric rate $0.02/KW ??? ;)

I just got a Kill-a-Watt in the mail and plugged in the freezer, because the frig is too hard to get to the plug (for now).

hmmm..... for 24 hr, it used 4KW ..that is far more than I was expecting!
if I do simple math and multiply by 30 days for a month ...that is 1/7 of my total useage ...I got the meter to see if I could justify a newer frig ..never thought the old freezer was that much of a hog. It runs at a bit below 300 watts, so it must be on around 50% of the time?? That's $15 /mo, so would need 3x improvement to justify cash outlay for new freezer.

So Paul, how many KW/day did your freezer originally use and then how much after the upgrade?


OT -- been interesting to plug in diff appliances around the house:

Found out that the satellite receiver only uses 20 watts, whether or not it is "on" ( hard disk inside always spins).

The DD receiver uses 1/3 less wattage if speakers are on A+B, rather than A or B alone ??...volume control does NOT effect wattage ie so OK to blast out the windows from a green perspective

The subwoofer amp which I thought was a 160 watt class A DC amp, in fact only draws about 20 watts typical but is a function of audio material ie louder means more .

Here is the fooler: the 55inch Plasma is rated at 500watts, which is supposed to be 2x the equivalent LCD set, but in fact only runs at shy of 300watts and depends upon scene brightness ...I am led to believe that LCD run full power all the time ( will check at a future date). For those hockey nuts in the crowd, the plasma is still the way to go vs LCD!
BTW, the newest sets are going to be laser:
http://www.hdtvmagazine.com/news/2008/01/mitsubishi_introduces_new_category_of_large-format_televisions_with_groundbreaking_laser_techn ology.php

MY biggest energy hog in winter is the oil furnace injector ...solved that by turning it off completely ...no fossil fuel to heat the house at all so far this winter. Hope the wood holds out

Still require the big air duct circulator running 12hrs/day, which is 1/6HP but says 5 amps on label ..thats close to 600watts ...don't believe it at this load tho (because summer bills and winter haven't changed much), but that will require some playing around to get the meter hooked up....if so, need to find a suitable replacement motor

Stew Corman from sunny Endicott

[Ralph Day]

Stew
What size is your freezer, and what age? OUr freezer is 12cuft and i've Kill a watted it at .8kw per day. It's in the heated basement and the power is the same year around. Our previous one was 20cuft at least, so we downsized and updated before we off-gridded...never chedked the old one's power consumption. Our fridge uses between .8 .9 or so kw per day, and it's energuide rating is 1.2kw per day. That must be with teens in the house openeing and closing a lot (Paul, n'est ce pas?).

ralph

[Paul Bailey]

Hi Guys Your Can follow the BLOG on this 0.1 Kwh/day fridge here and decipher the info... at

http://peakoildebunked.blogspot.com/2005/12/182-super-efficient-chest-fridge.html

[Stewart Corman]

Sorry guys, I was remiss in not stating the specs on that old freezer. It is a 21cuft Sears top of the line chest unit from probably 40 years ago ..still keeps tick'n.

I went to Sears.com and checked out the energy ratings of the larger chest type freezers and in fact , the new ones are about 1/3 the energy requirements of mine.

So the economics are that if instead of $15/mo, I cut it down by $10 ..that's a savings of $120/yr and the units cost about $600 or about a 5 year payback.
Since we have been putting up with it so long, a few more weeks for shopping might be prudent. Talking about "pru-dent" ..since it resides in the unfinished shop/basement, a "scratch and dent" unit would suffice if the discount is significant or "January white sale days", etc. Will wait until frig gets measured as well, but that is 18 cuft and 14 years ...still a teenager! Don't think the savings will be as spectacular, but who knows?? been wrong before.

Paul, you numbers are probably correct, so you don't have to respond unless the numbers are right at hand.


Stew

[Paul Bailey]

Hi Guys : As quoted on most Government energy sites ..The cut off point on most appliances is the 8-10 year mark and the NEW one will pay for itself in energy savings. It's tough getting rid of something that still works ( the old freezer in the basement or Garage for that matter) The problem lies here with inefficiency X the millions out there and we got a problem., And we wonder why our grid is near capacity. More later....Paul:)

[Stellar Gellar]

hmm this is interesting. unfortunately we don't have enough space for a large chest freezer. darn.

[Stewart Corman]

I had thought I posted it somewhere,but this thread is the most relevant.

I purchased a 20cuft chest freezer from Lowes on sale with a coupon for $405 delivered.
The sticker rating was NOT the best in it's category and isn't "energy star compliant", but the price was right. They claimed 480KWhr/yr ...measurement shows only 330

Didn't realize that it had a control knob for temp setting on the side ...set it to minimum cooling, since it gets opened less than once a day.

The old clunker was running at 4KW/day, while the new one runs at 130watts when on and only 0.9KW/day @ $0.12/KW = $3/mo = $39/yr vs $175 ...YES, I am very pleased, since my expectation was >1KW per day

Those were summer measurements and the basement might be 10 degrees cooler thru the winter, but I doubt it will make any sig diff

OT thought... never considered running a 400watt el cheapo 12v inverter from the car to frig or freezer if we had a prolonged power outage...always hear of people claiming they lost food ... at 130watt running, this shouldn't be a problem even with higher startup juice.

Now if I can only get my WVO burner project up and running, I can heat for free, but more importantly don't have to contend with firewood hassle.
I promised Rob that I will post a new thread when I have hardware to show, although it doesn't appear that there is much activity on this subject on this forum..

Stew Corman from sunny Endicott

[Ralph Day]

Hi Stew
Some experience with 12v inverters and freezers...not enough juice to start up. When our SW inverter died 2 years ago (repaired under warranty) and we had only a 1kw msw 12vdc inverter, all it could do was run some lights. When asked to run the freezer it made piggy squealing noises and wouldn't do it...the initial startup load was too much for it. Instead we put a propane heater in the generator house and kept the gen warm, then ran it for a couple of hours ever 6 or so until the replacement unit arrived (2 days later). This happened in December...when the power goes out and you're off-grid panic mode sets in faster than if you're on the grid!

Give your 12v inverter a try, but be prepared for lack of performance, the initial startup of compressor of a freezer is big.

Ralph

[Joe Blake]

I've now got 2 Engel 12/24/240 volt freezers, 40 litres

http://www.engelaustralia.com.au/cgi-bin/product.cgi?item_id=mt45f-s&item_string=

and 60 litres respectively.

http://www.engelaustralia.com.au/cgi-bin/product.cgi?item_id=mt60f&item_string=

Had my 40 litre one well over a year now, and it's been great.

There's no rotary compressor but a "swing motor", which doesn't need a start-up draw of current. The 40 litre draws a max of about 30 watts and the 60 litre draws about 60 watts.

http://www.engelaustralia.com.au/cgi-bin/swing_motor.cgi

I'm currently experimenting with turning off my "mains" 2 door fridge, having emptied its freezer into the 60 litre freezer, and using the 40 litre freezer to freeze 2 litre bottles of water to turn the big fridge into an "ice chest". It seems to run well, the ice keeps the fridge contents cooler than "lowest" (ie least cool) setting of the normal fridge. The only difficulty is that when it's running the main fridge condenses moisture onto its cooling plate and drains it out of the cabinet. The ice-chest is merely cool and very humid. Not good. So I've now turned the main fridge back on (to its lowest setting) but still put the ice bottles in on a daily basis. Since the freezer compartment is empty, it doesn't need much cooling, and I'm only hearing the fridge running once or twice a day (that doesn't mean however that's how often it's running.)

I'm waiting for my next power bill to see how much power consumption has dropped.

These freezers are not cheap, but at my stage of life, I'm no longer worried about money, I'm too old to care.

:cheesy:

Now it's summer and the solar panels are chugging away grandly. I've got 2x64 watts panels and 20x2.5 watt flexible panels. On a good day this gives me enough power to run

(a) 2 freezers
(b) 1 Pentium IV computer
(c) 1 LCD screen
(d) 1 tape transcriber
(e) 4 x LED light globes
(f) 1 x ADSL MODEM
(g) 1 x UPS
(h) 1 electric tricycle for occasional use.

And on this good day, the volt meter for the batteries shows they're holding close to 13 volts while still running all of the above.

I have a trickle charger on the batteries overnight, so in a sense I'm using some mains power to run the freezers. But the charger puts out less power than the freezer draw.

The big test came on Monday when the mains power was down for 6 or so hours due to upgrading of the poles, and I was able to do a full day's work and not lose any food due to defrosting.

And oh yeah, I had a hot shower because of the solar hot water system.


Joe

[Brian McGowan]

I have a small bank of Deep cycle batteries charged by 2 US-64 panels. I own another panel but it is not up yet. I have a small 750/1.5K MSW inverter that was not able to run the fridge or the washing machine but could run the dishwasher. I got a 2.5K/5K PSW inverter so I could run the fridge, heater and other things that I thought would be needed in a grid failure. I recently completed hooking a standard GM alternator to a lawn mower engine so it could provide power to run heavier items and charge the batteries as required when the grid goes down. Even if I have to run one thing at a time in round robin fasion (heater then fridge then another appliance and so forth) I should be able to keep myself alive during an extended power failure.
I think having this will provide me more flexiblilty in a grid failure. The only things in the house I won't be able to run are the water heater and the clothes dryer. I can do without the dryer but the water heater will be another story.
Brian