Thanks Johnmath
For the $40 freezer2fridge kit, would the standby power be zero ?
Would spending the extra for the My Best "plug and play" unit ($150) be a good investment ?
Low energy fridge and or freezer
(71 posts) (19 voices)-
Greg
MemberHere is an article where a conversion was done with a std controller off eBay with interesting results.
http://abdallahhouse.blogspot.com.au/2013/04/the-super-fridge-upright-freezer.htmlI think the mt best model is superior and of definite benefit to those off grid but hey any improvement ...
Edit: quick eBay search shows the digital temp controllers consume about 3W
Posted Monday 27 May 2013 @ 12:08:27 pm from IP # -
johnmath
MemberGreg said:
Edit: quick eBay search shows the digital temp controllers consume about 3WHmmm - 3 watts standby power means 3 x 24 = 72 wh/day, increasing the fridge's energy use by ~25% in Greg's linked example. I suspect that's why mechanical thermostats are offered by freidge2freezer - no standby power at all.
Posted Monday 27 May 2013 @ 12:50:02 pm from IP # -
According to my powermate lite my electronic controller with 3 digit LED temp display uses 0.9W standby and 1.9W relay operated. With a fridge freezer conversion the low duty cycle is likely to produce an average load of around 1.25W/hour.
The inbuilt temp display and alarm capability make it worth the losses.
Posted Monday 27 May 2013 @ 10:15:37 pm from IP # -
johnmath
MemberPhil A said:
Found this from NZ
As the testing was done by the one authority, at least it should be consistent?As far as I can see, the numbers are submitted by manufacturers and there is no requirement to provide supporting documentation, so it is an honour system...
(See example here: http://www.energywise.govt.nz/resource/energy-star®-fridges-registration-form )
Posted Thursday 30 May 2013 @ 4:22:03 am from IP # -
John Sheridan
MemberBeen looking at getting a 12 and or 24 volt fridge freezer combo, seems to be plenty to choose from, anyone have any recommendations.
Ones that use the least power would be a place, I have heard 24volt versions are more energy efficient in the long run.
Cheers.
Posted Saturday 24 Aug 2013 @ 9:44:55 pm from IP # -
MoreBikesPlease
MemberJohn, are you looking for a camping type fridge, or something bigger?
For a weekender I'm happy with the Waeco CF50:
http://www.waeco.com.au/products5.asp?id=334&catIdPosted Sunday 25 Aug 2013 @ 10:56:31 am from IP # -
John Sheridan
MemberI am looking for a fridge for my off grid place, all in one unit fridge freezer 50 to 150 liter fridge.
Like this.
http://caravansplus.com.au/catalog/product_info.php?products_id=13107
I really need a freezer I like my ice and is nice to store a little meat in there as well
Not sure the size at the moment, only need a small one, maybe like 90 liters, just going to be me, going to can and dehydrate most of my vegies and stuff.
No idea what brand and or tech would be best, but I know I want it to be at least 12 volts or 24 volts and be energy efficient so not to *@&*@&@ my batteries too much.
Thanks.
Posted Sunday 25 Aug 2013 @ 1:04:15 pm from IP # -
MoreBikesPlease
MemberJohn Sheridan said:
http://caravansplus.com.au/catalog/product_info.php?products_id=13107From the info on that page it looks good, with a Danfoss compressor. The insulation may be thin though. Claiming 40 Watt nominal consumption, that's 3.3 amps on 12V, or 79 amp-hours per day. I'm sceptical - I reckon it would use more than that.
Have you started working out how big your off-grid electrical system will be? Your main decision is whether to run appliances on 12V / 24V DC, or run them off 240V AC via an inverter. For a permanently-occupied house, the normal advice is to go 240V AC, unless your consumption is super-frugal, like at a caravan/cabin level.
240V appliances are so much cheaper and easier to get than 12/24V ones.For a "cabin" setup there's some info in this recent thread:
http://www.ata.org.au/forums/topic/10374Posted Sunday 25 Aug 2013 @ 10:42:37 pm from IP # -
John Sheridan
MemberI know the 240 ac appliances cost less, just walked past a shop with a fridge out front 150 liters or so for about 400 bucks, I want to pay 1000 for a 90 liter 12/24 volt one :0
I will be cabin level on electricity use I think, just me all alone, the only thing that will be on 24 7 would be the Fridge, maybe the Compost toilet fan
I have to figure out from that how many batterys and solar cells I need, no idea my self will need some experts to tell me, but I do know a little not to be ripped off, I want like 5 days of autonomy, no sun backup in the batteries, I think if the Fridge is the only 24/7 appliance, I think that would be easy, everything else will be 12/24 volts.
I have a year or so to choose my stuff, when I move in I wont have anything, just my portable solar kit to charge my phone and laptop and all food will be canned or packaged, wont get the appliances till my place is built, need a roof even 12/24 volt stuff don't like to get rained on
Thanks for the chat.
Posted Monday 26 Aug 2013 @ 2:09:22 am from IP # -
Johnnojack
MemberFridges which fit you requirements are available in Caravan accessories places. You can get both Engel and Waco in 90 litre size (front opening), check them out. To reduce the moderate power use build the fridge in, with extra polystyrene insulation on the sides and top and provide ventilation below the rear from outside the building. You should be able to find out the expected power use from the specs.
Posted Tuesday 27 Aug 2013 @ 12:40:49 pm from IP # -
Greg
MemberSome 12V applicances (not fridges) at this US site just for interest http://www.power-hunt.com/12-volt-products.php
Posted Wednesday 28 Aug 2013 @ 6:28:24 am from IP # -
John Sheridan
MemberYou mean like a vent on the bottom of the wall and a vent above the fridge on the wall and inclose it like a chimney, so the hot air would draw the cold air from the outside and circulate the air pass the back of the fridge.
Just place the compressor in that space and should be golden right.
Posted Sunday 1 Sep 2013 @ 4:59:31 pm from IP # -
ambishop
MemberI am working out the better of the three most efficient refrigeration methods and would like some input on my math skills. I think I have most of it covered but would really like feedback on this.
http://s23.postimg.org/hklw71g4r/chestcompare.png
It is a bit complicated but here is what I came up with
Most efficient uprights run 800W a day at 240V. 240V Fridge with inverter and a 25% factor for efficiency and cooling factor loss on opening and closing the thing. 4 Amps per hour @12v12v DC uprights run 6.25 Amps per hour no inverter needed. Here are some lower power smaller examples. http://www.kansaswindpower.net/refrigerators.htm at 32c ambient larger model running 82AH per day
Chest Freezer as Fridge with inverter temp controller and a 25% factor for efficiency and cooling factor loss on opening and closing the thing. .35 Amps per hour!
http://s23.postimg.org/hklw71g4r/chestcompare.png
What I am figuring is a Chest freezer AS Fridge on an inverter runs 200 hours on a 200AH battery till flat, the upright, 50 hours and the dc fridge runs 32. With DOD calculated your mileage may vary.
To charge 200AH I am looking at 6.5 hours on 2x200W panels using a 30amp Charge controller FROM FLAT. Plus since it should rarely go flat a small part of those 6.5 hours can power fridge.
Please let me know if you agree/disagree with my Math.
The best method by far would be using a Trompe (0.00 Amps power required as it generates cold compressed air with just running water), and releasing the isothermal compressed air out slowly into the coils of a fridge or freezer with the compressor removed. However I am not at the stage to be setting up a trompe as I do not have the running water for it. http://en.wikipedia.org/wiki/Trompe
Posted Sunday 8 Sep 2013 @ 11:26:30 pm from IP # -
Johnnojack
MemberJohn Sheridan said:
You mean like a vent on the bottom of the wall and a vent above the fridge on the wall and inclose it like a chimney, so the hot air would draw the cold air from the outside and circulate the air pass the back of the fridge.Just place the compressor in that space and should be golden right.
You got it.
To extend that idea I have read of people in Northern USA having food cupboard/coolbox with metal back built into outside wall. In winter it is colder than the fridge inside. Might take a bit of managing though, frozen milk and lettuce anyone? How cold is it where you are?Posted Monday 9 Sep 2013 @ 1:46:53 pm from IP # -
David
Memberambishop said:
Chest Freezer as Fridge with inverter temp controller and a 25% factor for efficiency and cooling factor loss on opening and closing the thing. .35 Amps per hour!I decided to build our own draw fridge, ran the design by a fridgie mate I know. He provided the compressor, heat exchanger and cooling core, all 240Vac. The little compressor and heat exchanger are outside works to treat. Don't know how many kWh it uses but its pretty good on power. The walls and bottom of the drawers are kind of thick though. It was what I was after.
Posted Monday 9 Sep 2013 @ 2:11:58 pm from IP # -
Lance
Key MasterIf you are going to build your own, you should check out this mob who have complete systems. Can't vouch for them, but looks like a good solution if you have a suitable cabinet: http://www.ozefridge.com.au
Posted Monday 9 Sep 2013 @ 11:14:43 pm from IP # -
wlb
MemberLance said:
Can't vouch for them, but ...I can.
I've had one since 2006 when our LPG Electrolux died for no apparent reason. It's a small, long-established family business that sells systems to boating people all over the world. Peter Mackay, the owner, has been in refrigeration for decades. You won't find a friendlier more helpful operator. They only use quality components and Peter is always looking at innovations.When the gas fridge died, I needed to do something quickly as we had to use a borrowed Engel, and we were heading into summer. I used a old 480L 2-door carcass that I modified for the purpose. It was to be temporary until we built a new kitchen and I could do exactly what you're planning - a drawer fridge. Alas that hasn't happen yet, but I'm still hopeful. Therefore we can't take advantage of the eutectic features because the cabinet insulation isn't what it should be so the hold-over time for the ice tank isn't good enough. If you use an Ozefridge, you really must pay careful attention to what they say about insulation. I wasn't that concerned because it was to be temporary. I just didn't know that temporary would be 7 years.
Give them a call and talk to Peter.
I'd be very interested to hear about your drawer design as it develops.
Posted Monday 9 Sep 2013 @ 11:38:05 pm from IP # -
Phil A
MemberSome feed back/follow up on the original post of this thread.
Thanks every one for the ensuing constructive discussion.
After following up the advice given above, we decided to go with the original models mentioned for the following reasons.
I found models which were more efficient as far as kw/hrs per litre of fridge space went, however for us the actual power used was also important.The 286 litre gram fridge claimed 389wh/day @25 degrees. As it is about 20 degrees here in or hydronically heated abode, the actual usage has been approx. 300-350wh/day.
It has zero standby current and the external condenser so extra insulation may well improve this figure a bit more. It has 45mm of the highest rated insulation, not 100mm as originally thought. (45 watt motor)
The elcold 130 litre chest freezer was installed in the unheated garage and also is using a lot less than the claimed 430 watt hrs/day. It has 100mm insulation. (90 watt motor) although it actually draws a lot less than this. In case of power failure it is rated to rise to minus 9 degrees in 52hrs. Not that we have had a power failure since being off grid.
Total for both is a very satisfactory less than 600 watt hrs/day.
Both units are also amazingly quiet compared to our old "kelvinator"
It will be interesting to see what some extra insulation might achieve.
Another bonus is the increased battery reserve capacity during low/no sun periods. Our old fridge/freezer used between 1.6-1.8 kwh/day. you do the maths.
Thanks again,
Phil.Posted Wednesday 11 Sep 2013 @ 11:47:15 am from IP # -
ambishop
MemberHere is what I am getting from my Freezer conversion.
http://s11.postimg.org/hk0jbkjg3/2013_09_23_07_26_49.jpg $50 Freezer, $30 external temp controller
8 c setting --Weather Today 26°C Tonight 12°C
Fridge Fullhttp://s12.postimg.org/cg1gijqjx/2013_09_23_07_28_34.jpg Idle power consumption
http://s15.postimg.org/yw2tdzxtn/2013_09_23_07_28_39.jpg Compressor On
http://s10.postimg.org/jo1gsk53t/2013_09_23_07_26_14.jpg Total Power Used in 3 days, 3 hours = 0.995KWH 75Hours 0.013266667 KW Per Hour
Posted Monday 23 Sep 2013 @ 7:39:57 am from IP # -
franks
MemberPVs being so cheap 80cents per watt, get an AC 4 star fridge freezer for $1200 (Eletrolux ETM4200 800WHr per day) and spend extra $400 on PVs
Still will be cheaper than a Waico CF110 fridge/freezer and you get 3 times the capacity with the Electrolux.Posted Monday 23 Sep 2013 @ 8:23:57 am from IP # -
dlvb19
MemberAgree with Franks,
I have the Electrolux ETM4200 and it uses less than the rated amount.
Our kitchen must average about 21 degrees over a 24 hour period and the average daily consumption of the unit is 0.58kWh. Coolness settings all left at medium where they started. Standby is less than a watt I think.
If you wanted to further reduce consumption you could dial down the temperature setting or use some sort of thermal mass (assuming solar panels).
Posted Monday 23 Sep 2013 @ 11:10:58 am from IP # -
Phil A
Memberambishop, 700 watts seems high when running? How long does the compressor run? is the 5 w stand by continuous current?
dlvb19, does the Electrolux include a 130 litre freezer?
Update
As the freezer is being filled it is using less than the above quoted figures. When I get time I will change the monitor over and post an update.Posted Monday 23 Sep 2013 @ 10:09:21 pm from IP # -
dlvb19
Memberhttp://www.electrolux.com.au/Products/Refrigeration/Fridges/Top_mount/ETM4200SC
Actually a 105 litre freezer.
Posted Monday 23 Sep 2013 @ 10:51:41 pm from IP # -
ambishop
MemberPhil A said:
ambishop, 700 watts seems high when running? How long does the compressor run? is the 5 w stand by continuous current?Freezer runs for no more than about 1-2 minutes per cycle. Yes I thought it was a little high as well, but it was $50. Plus according to the 800Whr/day of the Eletrolux ETM4200 mentioned I am getting 995/75hr*24 I am running 318.4WHr Per day. Or 2.5 times the efficiency. Not bad for $80 total! Given this I can run 2 of these and still be under the power of the Eletrolux ETM4200
5W is the lowest measured draw of the Power Meter. the power meter is not smart enough to give more details or go under 5W it seems. This is going to be the thermostat draw to keep the electronics alive. I think the specs are 3W per hour
13W PER HOUR Average. If I do some quick and likely wrong math... lets say 1 minute 700 Watt = 11.6666 For one minute. Then 59 minutes hardly anything but the draw from the thermostat. that is about right if you look at the math.
Kelvinator H211T $50.00 200 Liter Capacity - gumtree
Digital Temperature Controller Beer Fermentation Wired Fridge - ebay $19.95 plus 10 postage
Both running 116Kw annuallyPosted Monday 23 Sep 2013 @ 11:06:21 pm from IP # -
franks
MemberI have built a thermostat controller for my old 150 ltr upright freezer to use as beer & white wine fridge.
Using solid state relay and couple of op-amp chips..current draw on idle 3mA, when operating relay aprox 20mA..powered off 24 volt battery system.uses bugger all power on idle (0.1 watts) and only 150 watts from inverter when compressor is running.
Posted Tuesday 24 Sep 2013 @ 5:00:31 am from IP # -
ambishop
MemberI am wondering how this one runs at 5C
http://www.qdbeier.com/ArticleShow.asp?ArticleID=576
It is rated at 80W, which I assume is at Cooling performance: -18 at 30 ambient temperature
It has a thermostat that runs from 5c to -18c
Update from mfg
Q: please let me know the power consumption at this unit 5C in refrigerator mode at 12V
A: Appr.870wh /24hrs while the ambient temp at 32CHere is the interesting part. The company Beier will sell Spares of the compressor and compressor controller. You could in theory build your own using less than $200 in parts!
Posted Tuesday 24 Sep 2013 @ 9:47:39 am from IP #
